mirror of https://go.googlesource.com/go
4018 lines
120 KiB
Go
4018 lines
120 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package reflect
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import (
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"errors"
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"internal/abi"
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"internal/goarch"
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"internal/itoa"
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"internal/unsafeheader"
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"math"
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"runtime"
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"unsafe"
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)
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// Value is the reflection interface to a Go value.
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//
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// Not all methods apply to all kinds of values. Restrictions,
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// if any, are noted in the documentation for each method.
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// Use the Kind method to find out the kind of value before
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// calling kind-specific methods. Calling a method
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// inappropriate to the kind of type causes a run time panic.
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//
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// The zero Value represents no value.
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// Its [Value.IsValid] method returns false, its Kind method returns [Invalid],
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// its String method returns "<invalid Value>", and all other methods panic.
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// Most functions and methods never return an invalid value.
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// If one does, its documentation states the conditions explicitly.
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//
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// A Value can be used concurrently by multiple goroutines provided that
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// the underlying Go value can be used concurrently for the equivalent
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// direct operations.
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//
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// To compare two Values, compare the results of the Interface method.
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// Using == on two Values does not compare the underlying values
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// they represent.
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type Value struct {
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// typ_ holds the type of the value represented by a Value.
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// Access using the typ method to avoid escape of v.
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typ_ *abi.Type
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// Pointer-valued data or, if flagIndir is set, pointer to data.
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// Valid when either flagIndir is set or typ.pointers() is true.
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ptr unsafe.Pointer
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// flag holds metadata about the value.
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//
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// The lowest five bits give the Kind of the value, mirroring typ.Kind().
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//
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// The next set of bits are flag bits:
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// - flagStickyRO: obtained via unexported not embedded field, so read-only
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// - flagEmbedRO: obtained via unexported embedded field, so read-only
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// - flagIndir: val holds a pointer to the data
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// - flagAddr: v.CanAddr is true (implies flagIndir and ptr is non-nil)
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// - flagMethod: v is a method value.
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// If ifaceIndir(typ), code can assume that flagIndir is set.
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//
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// The remaining 22+ bits give a method number for method values.
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// If flag.kind() != Func, code can assume that flagMethod is unset.
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flag
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// A method value represents a curried method invocation
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// like r.Read for some receiver r. The typ+val+flag bits describe
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// the receiver r, but the flag's Kind bits say Func (methods are
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// functions), and the top bits of the flag give the method number
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// in r's type's method table.
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}
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type flag uintptr
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const (
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flagKindWidth = 5 // there are 27 kinds
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flagKindMask flag = 1<<flagKindWidth - 1
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flagStickyRO flag = 1 << 5
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flagEmbedRO flag = 1 << 6
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flagIndir flag = 1 << 7
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flagAddr flag = 1 << 8
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flagMethod flag = 1 << 9
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flagMethodShift = 10
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flagRO flag = flagStickyRO | flagEmbedRO
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)
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func (f flag) kind() Kind {
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return Kind(f & flagKindMask)
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}
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func (f flag) ro() flag {
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if f&flagRO != 0 {
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return flagStickyRO
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}
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return 0
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}
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func (v Value) typ() *abi.Type {
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// Types are either static (for compiler-created types) or
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// heap-allocated but always reachable (for reflection-created
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// types, held in the central map). So there is no need to
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// escape types. noescape here help avoid unnecessary escape
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// of v.
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return (*abi.Type)(abi.NoEscape(unsafe.Pointer(v.typ_)))
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}
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// pointer returns the underlying pointer represented by v.
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// v.Kind() must be Pointer, Map, Chan, Func, or UnsafePointer
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// if v.Kind() == Pointer, the base type must not be not-in-heap.
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func (v Value) pointer() unsafe.Pointer {
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if v.typ().Size() != goarch.PtrSize || !v.typ().Pointers() {
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panic("can't call pointer on a non-pointer Value")
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}
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if v.flag&flagIndir != 0 {
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return *(*unsafe.Pointer)(v.ptr)
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}
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return v.ptr
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}
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// packEface converts v to the empty interface.
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func packEface(v Value) any {
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t := v.typ()
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var i any
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e := (*abi.EmptyInterface)(unsafe.Pointer(&i))
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// First, fill in the data portion of the interface.
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switch {
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case t.IfaceIndir():
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if v.flag&flagIndir == 0 {
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panic("bad indir")
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}
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// Value is indirect, and so is the interface we're making.
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ptr := v.ptr
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if v.flag&flagAddr != 0 {
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c := unsafe_New(t)
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typedmemmove(t, c, ptr)
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ptr = c
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}
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e.Data = ptr
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case v.flag&flagIndir != 0:
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// Value is indirect, but interface is direct. We need
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// to load the data at v.ptr into the interface data word.
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e.Data = *(*unsafe.Pointer)(v.ptr)
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default:
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// Value is direct, and so is the interface.
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e.Data = v.ptr
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}
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// Now, fill in the type portion. We're very careful here not
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// to have any operation between the e.word and e.typ assignments
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// that would let the garbage collector observe the partially-built
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// interface value.
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e.Type = t
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return i
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}
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// unpackEface converts the empty interface i to a Value.
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func unpackEface(i any) Value {
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e := (*abi.EmptyInterface)(unsafe.Pointer(&i))
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// NOTE: don't read e.word until we know whether it is really a pointer or not.
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t := e.Type
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if t == nil {
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return Value{}
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}
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f := flag(t.Kind())
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if t.IfaceIndir() {
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f |= flagIndir
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}
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return Value{t, e.Data, f}
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}
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// A ValueError occurs when a Value method is invoked on
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// a [Value] that does not support it. Such cases are documented
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// in the description of each method.
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type ValueError struct {
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Method string
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Kind Kind
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}
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func (e *ValueError) Error() string {
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if e.Kind == 0 {
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return "reflect: call of " + e.Method + " on zero Value"
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}
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return "reflect: call of " + e.Method + " on " + e.Kind.String() + " Value"
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}
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// valueMethodName returns the name of the exported calling method on Value.
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func valueMethodName() string {
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var pc [5]uintptr
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n := runtime.Callers(1, pc[:])
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frames := runtime.CallersFrames(pc[:n])
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var frame runtime.Frame
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for more := true; more; {
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const prefix = "reflect.Value."
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frame, more = frames.Next()
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name := frame.Function
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if len(name) > len(prefix) && name[:len(prefix)] == prefix {
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methodName := name[len(prefix):]
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if len(methodName) > 0 && 'A' <= methodName[0] && methodName[0] <= 'Z' {
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return name
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}
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}
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}
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return "unknown method"
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}
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// nonEmptyInterface is the header for an interface value with methods.
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type nonEmptyInterface struct {
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itab *abi.ITab
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word unsafe.Pointer
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}
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// mustBe panics if f's kind is not expected.
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// Making this a method on flag instead of on Value
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// (and embedding flag in Value) means that we can write
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// the very clear v.mustBe(Bool) and have it compile into
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// v.flag.mustBe(Bool), which will only bother to copy the
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// single important word for the receiver.
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func (f flag) mustBe(expected Kind) {
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// TODO(mvdan): use f.kind() again once mid-stack inlining gets better
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if Kind(f&flagKindMask) != expected {
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panic(&ValueError{valueMethodName(), f.kind()})
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}
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}
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// mustBeExported panics if f records that the value was obtained using
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// an unexported field.
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func (f flag) mustBeExported() {
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if f == 0 || f&flagRO != 0 {
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f.mustBeExportedSlow()
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}
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}
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func (f flag) mustBeExportedSlow() {
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if f == 0 {
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panic(&ValueError{valueMethodName(), Invalid})
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}
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if f&flagRO != 0 {
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panic("reflect: " + valueMethodName() + " using value obtained using unexported field")
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}
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}
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// mustBeAssignable panics if f records that the value is not assignable,
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// which is to say that either it was obtained using an unexported field
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// or it is not addressable.
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func (f flag) mustBeAssignable() {
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if f&flagRO != 0 || f&flagAddr == 0 {
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f.mustBeAssignableSlow()
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}
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}
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func (f flag) mustBeAssignableSlow() {
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if f == 0 {
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panic(&ValueError{valueMethodName(), Invalid})
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}
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// Assignable if addressable and not read-only.
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if f&flagRO != 0 {
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panic("reflect: " + valueMethodName() + " using value obtained using unexported field")
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}
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if f&flagAddr == 0 {
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panic("reflect: " + valueMethodName() + " using unaddressable value")
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}
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}
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// Addr returns a pointer value representing the address of v.
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// It panics if [Value.CanAddr] returns false.
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// Addr is typically used to obtain a pointer to a struct field
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// or slice element in order to call a method that requires a
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// pointer receiver.
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func (v Value) Addr() Value {
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if v.flag&flagAddr == 0 {
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panic("reflect.Value.Addr of unaddressable value")
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}
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// Preserve flagRO instead of using v.flag.ro() so that
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// v.Addr().Elem() is equivalent to v (#32772)
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fl := v.flag & flagRO
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return Value{ptrTo(v.typ()), v.ptr, fl | flag(Pointer)}
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}
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// Bool returns v's underlying value.
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// It panics if v's kind is not [Bool].
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func (v Value) Bool() bool {
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// panicNotBool is split out to keep Bool inlineable.
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if v.kind() != Bool {
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v.panicNotBool()
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}
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return *(*bool)(v.ptr)
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}
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func (v Value) panicNotBool() {
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v.mustBe(Bool)
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}
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var bytesType = rtypeOf(([]byte)(nil))
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// Bytes returns v's underlying value.
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// It panics if v's underlying value is not a slice of bytes or
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// an addressable array of bytes.
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func (v Value) Bytes() []byte {
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// bytesSlow is split out to keep Bytes inlineable for unnamed []byte.
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if v.typ_ == bytesType { // ok to use v.typ_ directly as comparison doesn't cause escape
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return *(*[]byte)(v.ptr)
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}
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return v.bytesSlow()
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}
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func (v Value) bytesSlow() []byte {
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switch v.kind() {
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case Slice:
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if v.typ().Elem().Kind() != abi.Uint8 {
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panic("reflect.Value.Bytes of non-byte slice")
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}
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// Slice is always bigger than a word; assume flagIndir.
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return *(*[]byte)(v.ptr)
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case Array:
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if v.typ().Elem().Kind() != abi.Uint8 {
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panic("reflect.Value.Bytes of non-byte array")
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}
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if !v.CanAddr() {
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panic("reflect.Value.Bytes of unaddressable byte array")
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}
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p := (*byte)(v.ptr)
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n := int((*arrayType)(unsafe.Pointer(v.typ())).Len)
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return unsafe.Slice(p, n)
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}
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panic(&ValueError{"reflect.Value.Bytes", v.kind()})
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}
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// runes returns v's underlying value.
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// It panics if v's underlying value is not a slice of runes (int32s).
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func (v Value) runes() []rune {
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v.mustBe(Slice)
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if v.typ().Elem().Kind() != abi.Int32 {
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panic("reflect.Value.Bytes of non-rune slice")
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}
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// Slice is always bigger than a word; assume flagIndir.
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return *(*[]rune)(v.ptr)
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}
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// CanAddr reports whether the value's address can be obtained with [Value.Addr].
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// Such values are called addressable. A value is addressable if it is
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// an element of a slice, an element of an addressable array,
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// a field of an addressable struct, or the result of dereferencing a pointer.
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// If CanAddr returns false, calling [Value.Addr] will panic.
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func (v Value) CanAddr() bool {
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return v.flag&flagAddr != 0
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}
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// CanSet reports whether the value of v can be changed.
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// A [Value] can be changed only if it is addressable and was not
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// obtained by the use of unexported struct fields.
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// If CanSet returns false, calling [Value.Set] or any type-specific
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// setter (e.g., [Value.SetBool], [Value.SetInt]) will panic.
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func (v Value) CanSet() bool {
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return v.flag&(flagAddr|flagRO) == flagAddr
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}
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// Call calls the function v with the input arguments in.
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// For example, if len(in) == 3, v.Call(in) represents the Go call v(in[0], in[1], in[2]).
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// Call panics if v's Kind is not [Func].
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// It returns the output results as Values.
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// As in Go, each input argument must be assignable to the
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// type of the function's corresponding input parameter.
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// If v is a variadic function, Call creates the variadic slice parameter
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// itself, copying in the corresponding values.
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func (v Value) Call(in []Value) []Value {
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v.mustBe(Func)
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v.mustBeExported()
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return v.call("Call", in)
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}
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// CallSlice calls the variadic function v with the input arguments in,
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// assigning the slice in[len(in)-1] to v's final variadic argument.
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// For example, if len(in) == 3, v.CallSlice(in) represents the Go call v(in[0], in[1], in[2]...).
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// CallSlice panics if v's Kind is not [Func] or if v is not variadic.
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// It returns the output results as Values.
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// As in Go, each input argument must be assignable to the
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// type of the function's corresponding input parameter.
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func (v Value) CallSlice(in []Value) []Value {
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v.mustBe(Func)
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v.mustBeExported()
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return v.call("CallSlice", in)
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}
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var callGC bool // for testing; see TestCallMethodJump and TestCallArgLive
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const debugReflectCall = false
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func (v Value) call(op string, in []Value) []Value {
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// Get function pointer, type.
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t := (*funcType)(unsafe.Pointer(v.typ()))
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var (
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fn unsafe.Pointer
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rcvr Value
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rcvrtype *abi.Type
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)
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if v.flag&flagMethod != 0 {
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rcvr = v
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rcvrtype, t, fn = methodReceiver(op, v, int(v.flag)>>flagMethodShift)
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} else if v.flag&flagIndir != 0 {
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fn = *(*unsafe.Pointer)(v.ptr)
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} else {
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fn = v.ptr
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}
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if fn == nil {
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panic("reflect.Value.Call: call of nil function")
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}
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isSlice := op == "CallSlice"
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n := t.NumIn()
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isVariadic := t.IsVariadic()
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if isSlice {
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if !isVariadic {
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panic("reflect: CallSlice of non-variadic function")
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}
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if len(in) < n {
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panic("reflect: CallSlice with too few input arguments")
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}
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if len(in) > n {
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panic("reflect: CallSlice with too many input arguments")
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}
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} else {
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if isVariadic {
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n--
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}
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if len(in) < n {
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panic("reflect: Call with too few input arguments")
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}
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if !isVariadic && len(in) > n {
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panic("reflect: Call with too many input arguments")
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}
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}
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for _, x := range in {
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if x.Kind() == Invalid {
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panic("reflect: " + op + " using zero Value argument")
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}
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}
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for i := 0; i < n; i++ {
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if xt, targ := in[i].Type(), t.In(i); !xt.AssignableTo(toRType(targ)) {
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panic("reflect: " + op + " using " + xt.String() + " as type " + stringFor(targ))
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}
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}
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if !isSlice && isVariadic {
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// prepare slice for remaining values
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m := len(in) - n
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slice := MakeSlice(toRType(t.In(n)), m, m)
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elem := toRType(t.In(n)).Elem() // FIXME cast to slice type and Elem()
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for i := 0; i < m; i++ {
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x := in[n+i]
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if xt := x.Type(); !xt.AssignableTo(elem) {
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panic("reflect: cannot use " + xt.String() + " as type " + elem.String() + " in " + op)
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}
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slice.Index(i).Set(x)
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}
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origIn := in
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in = make([]Value, n+1)
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copy(in[:n], origIn)
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in[n] = slice
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}
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nin := len(in)
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if nin != t.NumIn() {
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panic("reflect.Value.Call: wrong argument count")
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}
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nout := t.NumOut()
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// Register argument space.
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var regArgs abi.RegArgs
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// Compute frame type.
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frametype, framePool, abid := funcLayout(t, rcvrtype)
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// Allocate a chunk of memory for frame if needed.
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var stackArgs unsafe.Pointer
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if frametype.Size() != 0 {
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if nout == 0 {
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stackArgs = framePool.Get().(unsafe.Pointer)
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} else {
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// Can't use pool if the function has return values.
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// We will leak pointer to args in ret, so its lifetime is not scoped.
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stackArgs = unsafe_New(frametype)
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}
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}
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frameSize := frametype.Size()
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if debugReflectCall {
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println("reflect.call", stringFor(&t.Type))
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abid.dump()
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}
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// Copy inputs into args.
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// Handle receiver.
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inStart := 0
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if rcvrtype != nil {
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// Guaranteed to only be one word in size,
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// so it will only take up exactly 1 abiStep (either
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// in a register or on the stack).
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switch st := abid.call.steps[0]; st.kind {
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case abiStepStack:
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storeRcvr(rcvr, stackArgs)
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case abiStepPointer:
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storeRcvr(rcvr, unsafe.Pointer(®Args.Ptrs[st.ireg]))
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fallthrough
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case abiStepIntReg:
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storeRcvr(rcvr, unsafe.Pointer(®Args.Ints[st.ireg]))
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case abiStepFloatReg:
|
|
storeRcvr(rcvr, unsafe.Pointer(®Args.Floats[st.freg]))
|
|
default:
|
|
panic("unknown ABI parameter kind")
|
|
}
|
|
inStart = 1
|
|
}
|
|
|
|
// Handle arguments.
|
|
for i, v := range in {
|
|
v.mustBeExported()
|
|
targ := toRType(t.In(i))
|
|
// TODO(mknyszek): Figure out if it's possible to get some
|
|
// scratch space for this assignment check. Previously, it
|
|
// was possible to use space in the argument frame.
|
|
v = v.assignTo("reflect.Value.Call", &targ.t, nil)
|
|
stepsLoop:
|
|
for _, st := range abid.call.stepsForValue(i + inStart) {
|
|
switch st.kind {
|
|
case abiStepStack:
|
|
// Copy values to the "stack."
|
|
addr := add(stackArgs, st.stkOff, "precomputed stack arg offset")
|
|
if v.flag&flagIndir != 0 {
|
|
typedmemmove(&targ.t, addr, v.ptr)
|
|
} else {
|
|
*(*unsafe.Pointer)(addr) = v.ptr
|
|
}
|
|
// There's only one step for a stack-allocated value.
|
|
break stepsLoop
|
|
case abiStepIntReg, abiStepPointer:
|
|
// Copy values to "integer registers."
|
|
if v.flag&flagIndir != 0 {
|
|
offset := add(v.ptr, st.offset, "precomputed value offset")
|
|
if st.kind == abiStepPointer {
|
|
// Duplicate this pointer in the pointer area of the
|
|
// register space. Otherwise, there's the potential for
|
|
// this to be the last reference to v.ptr.
|
|
regArgs.Ptrs[st.ireg] = *(*unsafe.Pointer)(offset)
|
|
}
|
|
intToReg(®Args, st.ireg, st.size, offset)
|
|
} else {
|
|
if st.kind == abiStepPointer {
|
|
// See the comment in abiStepPointer case above.
|
|
regArgs.Ptrs[st.ireg] = v.ptr
|
|
}
|
|
regArgs.Ints[st.ireg] = uintptr(v.ptr)
|
|
}
|
|
case abiStepFloatReg:
|
|
// Copy values to "float registers."
|
|
if v.flag&flagIndir == 0 {
|
|
panic("attempted to copy pointer to FP register")
|
|
}
|
|
offset := add(v.ptr, st.offset, "precomputed value offset")
|
|
floatToReg(®Args, st.freg, st.size, offset)
|
|
default:
|
|
panic("unknown ABI part kind")
|
|
}
|
|
}
|
|
}
|
|
// TODO(mknyszek): Remove this when we no longer have
|
|
// caller reserved spill space.
|
|
frameSize = align(frameSize, goarch.PtrSize)
|
|
frameSize += abid.spill
|
|
|
|
// Mark pointers in registers for the return path.
|
|
regArgs.ReturnIsPtr = abid.outRegPtrs
|
|
|
|
if debugReflectCall {
|
|
regArgs.Dump()
|
|
}
|
|
|
|
// For testing; see TestCallArgLive.
|
|
if callGC {
|
|
runtime.GC()
|
|
}
|
|
|
|
// Call.
|
|
call(frametype, fn, stackArgs, uint32(frametype.Size()), uint32(abid.retOffset), uint32(frameSize), ®Args)
|
|
|
|
// For testing; see TestCallMethodJump.
|
|
if callGC {
|
|
runtime.GC()
|
|
}
|
|
|
|
var ret []Value
|
|
if nout == 0 {
|
|
if stackArgs != nil {
|
|
typedmemclr(frametype, stackArgs)
|
|
framePool.Put(stackArgs)
|
|
}
|
|
} else {
|
|
if stackArgs != nil {
|
|
// Zero the now unused input area of args,
|
|
// because the Values returned by this function contain pointers to the args object,
|
|
// and will thus keep the args object alive indefinitely.
|
|
typedmemclrpartial(frametype, stackArgs, 0, abid.retOffset)
|
|
}
|
|
|
|
// Wrap Values around return values in args.
|
|
ret = make([]Value, nout)
|
|
for i := 0; i < nout; i++ {
|
|
tv := t.Out(i)
|
|
if tv.Size() == 0 {
|
|
// For zero-sized return value, args+off may point to the next object.
|
|
// In this case, return the zero value instead.
|
|
ret[i] = Zero(toRType(tv))
|
|
continue
|
|
}
|
|
steps := abid.ret.stepsForValue(i)
|
|
if st := steps[0]; st.kind == abiStepStack {
|
|
// This value is on the stack. If part of a value is stack
|
|
// allocated, the entire value is according to the ABI. So
|
|
// just make an indirection into the allocated frame.
|
|
fl := flagIndir | flag(tv.Kind())
|
|
ret[i] = Value{tv, add(stackArgs, st.stkOff, "tv.Size() != 0"), fl}
|
|
// Note: this does introduce false sharing between results -
|
|
// if any result is live, they are all live.
|
|
// (And the space for the args is live as well, but as we've
|
|
// cleared that space it isn't as big a deal.)
|
|
continue
|
|
}
|
|
|
|
// Handle pointers passed in registers.
|
|
if !tv.IfaceIndir() {
|
|
// Pointer-valued data gets put directly
|
|
// into v.ptr.
|
|
if steps[0].kind != abiStepPointer {
|
|
print("kind=", steps[0].kind, ", type=", stringFor(tv), "\n")
|
|
panic("mismatch between ABI description and types")
|
|
}
|
|
ret[i] = Value{tv, regArgs.Ptrs[steps[0].ireg], flag(tv.Kind())}
|
|
continue
|
|
}
|
|
|
|
// All that's left is values passed in registers that we need to
|
|
// create space for and copy values back into.
|
|
//
|
|
// TODO(mknyszek): We make a new allocation for each register-allocated
|
|
// value, but previously we could always point into the heap-allocated
|
|
// stack frame. This is a regression that could be fixed by adding
|
|
// additional space to the allocated stack frame and storing the
|
|
// register-allocated return values into the allocated stack frame and
|
|
// referring there in the resulting Value.
|
|
s := unsafe_New(tv)
|
|
for _, st := range steps {
|
|
switch st.kind {
|
|
case abiStepIntReg:
|
|
offset := add(s, st.offset, "precomputed value offset")
|
|
intFromReg(®Args, st.ireg, st.size, offset)
|
|
case abiStepPointer:
|
|
s := add(s, st.offset, "precomputed value offset")
|
|
*((*unsafe.Pointer)(s)) = regArgs.Ptrs[st.ireg]
|
|
case abiStepFloatReg:
|
|
offset := add(s, st.offset, "precomputed value offset")
|
|
floatFromReg(®Args, st.freg, st.size, offset)
|
|
case abiStepStack:
|
|
panic("register-based return value has stack component")
|
|
default:
|
|
panic("unknown ABI part kind")
|
|
}
|
|
}
|
|
ret[i] = Value{tv, s, flagIndir | flag(tv.Kind())}
|
|
}
|
|
}
|
|
|
|
return ret
|
|
}
|
|
|
|
// callReflect is the call implementation used by a function
|
|
// returned by MakeFunc. In many ways it is the opposite of the
|
|
// method Value.call above. The method above converts a call using Values
|
|
// into a call of a function with a concrete argument frame, while
|
|
// callReflect converts a call of a function with a concrete argument
|
|
// frame into a call using Values.
|
|
// It is in this file so that it can be next to the call method above.
|
|
// The remainder of the MakeFunc implementation is in makefunc.go.
|
|
//
|
|
// NOTE: This function must be marked as a "wrapper" in the generated code,
|
|
// so that the linker can make it work correctly for panic and recover.
|
|
// The gc compilers know to do that for the name "reflect.callReflect".
|
|
//
|
|
// ctxt is the "closure" generated by MakeFunc.
|
|
// frame is a pointer to the arguments to that closure on the stack.
|
|
// retValid points to a boolean which should be set when the results
|
|
// section of frame is set.
|
|
//
|
|
// regs contains the argument values passed in registers and will contain
|
|
// the values returned from ctxt.fn in registers.
|
|
func callReflect(ctxt *makeFuncImpl, frame unsafe.Pointer, retValid *bool, regs *abi.RegArgs) {
|
|
if callGC {
|
|
// Call GC upon entry during testing.
|
|
// Getting our stack scanned here is the biggest hazard, because
|
|
// our caller (makeFuncStub) could have failed to place the last
|
|
// pointer to a value in regs' pointer space, in which case it
|
|
// won't be visible to the GC.
|
|
runtime.GC()
|
|
}
|
|
ftyp := ctxt.ftyp
|
|
f := ctxt.fn
|
|
|
|
_, _, abid := funcLayout(ftyp, nil)
|
|
|
|
// Copy arguments into Values.
|
|
ptr := frame
|
|
in := make([]Value, 0, int(ftyp.InCount))
|
|
for i, typ := range ftyp.InSlice() {
|
|
if typ.Size() == 0 {
|
|
in = append(in, Zero(toRType(typ)))
|
|
continue
|
|
}
|
|
v := Value{typ, nil, flag(typ.Kind())}
|
|
steps := abid.call.stepsForValue(i)
|
|
if st := steps[0]; st.kind == abiStepStack {
|
|
if typ.IfaceIndir() {
|
|
// value cannot be inlined in interface data.
|
|
// Must make a copy, because f might keep a reference to it,
|
|
// and we cannot let f keep a reference to the stack frame
|
|
// after this function returns, not even a read-only reference.
|
|
v.ptr = unsafe_New(typ)
|
|
if typ.Size() > 0 {
|
|
typedmemmove(typ, v.ptr, add(ptr, st.stkOff, "typ.size > 0"))
|
|
}
|
|
v.flag |= flagIndir
|
|
} else {
|
|
v.ptr = *(*unsafe.Pointer)(add(ptr, st.stkOff, "1-ptr"))
|
|
}
|
|
} else {
|
|
if typ.IfaceIndir() {
|
|
// All that's left is values passed in registers that we need to
|
|
// create space for the values.
|
|
v.flag |= flagIndir
|
|
v.ptr = unsafe_New(typ)
|
|
for _, st := range steps {
|
|
switch st.kind {
|
|
case abiStepIntReg:
|
|
offset := add(v.ptr, st.offset, "precomputed value offset")
|
|
intFromReg(regs, st.ireg, st.size, offset)
|
|
case abiStepPointer:
|
|
s := add(v.ptr, st.offset, "precomputed value offset")
|
|
*((*unsafe.Pointer)(s)) = regs.Ptrs[st.ireg]
|
|
case abiStepFloatReg:
|
|
offset := add(v.ptr, st.offset, "precomputed value offset")
|
|
floatFromReg(regs, st.freg, st.size, offset)
|
|
case abiStepStack:
|
|
panic("register-based return value has stack component")
|
|
default:
|
|
panic("unknown ABI part kind")
|
|
}
|
|
}
|
|
} else {
|
|
// Pointer-valued data gets put directly
|
|
// into v.ptr.
|
|
if steps[0].kind != abiStepPointer {
|
|
print("kind=", steps[0].kind, ", type=", stringFor(typ), "\n")
|
|
panic("mismatch between ABI description and types")
|
|
}
|
|
v.ptr = regs.Ptrs[steps[0].ireg]
|
|
}
|
|
}
|
|
in = append(in, v)
|
|
}
|
|
|
|
// Call underlying function.
|
|
out := f(in)
|
|
numOut := ftyp.NumOut()
|
|
if len(out) != numOut {
|
|
panic("reflect: wrong return count from function created by MakeFunc")
|
|
}
|
|
|
|
// Copy results back into argument frame and register space.
|
|
if numOut > 0 {
|
|
for i, typ := range ftyp.OutSlice() {
|
|
v := out[i]
|
|
if v.typ() == nil {
|
|
panic("reflect: function created by MakeFunc using " + funcName(f) +
|
|
" returned zero Value")
|
|
}
|
|
if v.flag&flagRO != 0 {
|
|
panic("reflect: function created by MakeFunc using " + funcName(f) +
|
|
" returned value obtained from unexported field")
|
|
}
|
|
if typ.Size() == 0 {
|
|
continue
|
|
}
|
|
|
|
// Convert v to type typ if v is assignable to a variable
|
|
// of type t in the language spec.
|
|
// See issue 28761.
|
|
//
|
|
//
|
|
// TODO(mknyszek): In the switch to the register ABI we lost
|
|
// the scratch space here for the register cases (and
|
|
// temporarily for all the cases).
|
|
//
|
|
// If/when this happens, take note of the following:
|
|
//
|
|
// We must clear the destination before calling assignTo,
|
|
// in case assignTo writes (with memory barriers) to the
|
|
// target location used as scratch space. See issue 39541.
|
|
v = v.assignTo("reflect.MakeFunc", typ, nil)
|
|
stepsLoop:
|
|
for _, st := range abid.ret.stepsForValue(i) {
|
|
switch st.kind {
|
|
case abiStepStack:
|
|
// Copy values to the "stack."
|
|
addr := add(ptr, st.stkOff, "precomputed stack arg offset")
|
|
// Do not use write barriers. The stack space used
|
|
// for this call is not adequately zeroed, and we
|
|
// are careful to keep the arguments alive until we
|
|
// return to makeFuncStub's caller.
|
|
if v.flag&flagIndir != 0 {
|
|
memmove(addr, v.ptr, st.size)
|
|
} else {
|
|
// This case must be a pointer type.
|
|
*(*uintptr)(addr) = uintptr(v.ptr)
|
|
}
|
|
// There's only one step for a stack-allocated value.
|
|
break stepsLoop
|
|
case abiStepIntReg, abiStepPointer:
|
|
// Copy values to "integer registers."
|
|
if v.flag&flagIndir != 0 {
|
|
offset := add(v.ptr, st.offset, "precomputed value offset")
|
|
intToReg(regs, st.ireg, st.size, offset)
|
|
} else {
|
|
// Only populate the Ints space on the return path.
|
|
// This is safe because out is kept alive until the
|
|
// end of this function, and the return path through
|
|
// makeFuncStub has no preemption, so these pointers
|
|
// are always visible to the GC.
|
|
regs.Ints[st.ireg] = uintptr(v.ptr)
|
|
}
|
|
case abiStepFloatReg:
|
|
// Copy values to "float registers."
|
|
if v.flag&flagIndir == 0 {
|
|
panic("attempted to copy pointer to FP register")
|
|
}
|
|
offset := add(v.ptr, st.offset, "precomputed value offset")
|
|
floatToReg(regs, st.freg, st.size, offset)
|
|
default:
|
|
panic("unknown ABI part kind")
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Announce that the return values are valid.
|
|
// After this point the runtime can depend on the return values being valid.
|
|
*retValid = true
|
|
|
|
// We have to make sure that the out slice lives at least until
|
|
// the runtime knows the return values are valid. Otherwise, the
|
|
// return values might not be scanned by anyone during a GC.
|
|
// (out would be dead, and the return slots not yet alive.)
|
|
runtime.KeepAlive(out)
|
|
|
|
// runtime.getArgInfo expects to be able to find ctxt on the
|
|
// stack when it finds our caller, makeFuncStub. Make sure it
|
|
// doesn't get garbage collected.
|
|
runtime.KeepAlive(ctxt)
|
|
}
|
|
|
|
// methodReceiver returns information about the receiver
|
|
// described by v. The Value v may or may not have the
|
|
// flagMethod bit set, so the kind cached in v.flag should
|
|
// not be used.
|
|
// The return value rcvrtype gives the method's actual receiver type.
|
|
// The return value t gives the method type signature (without the receiver).
|
|
// The return value fn is a pointer to the method code.
|
|
func methodReceiver(op string, v Value, methodIndex int) (rcvrtype *abi.Type, t *funcType, fn unsafe.Pointer) {
|
|
i := methodIndex
|
|
if v.typ().Kind() == abi.Interface {
|
|
tt := (*interfaceType)(unsafe.Pointer(v.typ()))
|
|
if uint(i) >= uint(len(tt.Methods)) {
|
|
panic("reflect: internal error: invalid method index")
|
|
}
|
|
m := &tt.Methods[i]
|
|
if !tt.nameOff(m.Name).IsExported() {
|
|
panic("reflect: " + op + " of unexported method")
|
|
}
|
|
iface := (*nonEmptyInterface)(v.ptr)
|
|
if iface.itab == nil {
|
|
panic("reflect: " + op + " of method on nil interface value")
|
|
}
|
|
rcvrtype = iface.itab.Type
|
|
fn = unsafe.Pointer(&unsafe.Slice(&iface.itab.Fun[0], i+1)[i])
|
|
t = (*funcType)(unsafe.Pointer(tt.typeOff(m.Typ)))
|
|
} else {
|
|
rcvrtype = v.typ()
|
|
ms := v.typ().ExportedMethods()
|
|
if uint(i) >= uint(len(ms)) {
|
|
panic("reflect: internal error: invalid method index")
|
|
}
|
|
m := ms[i]
|
|
if !nameOffFor(v.typ(), m.Name).IsExported() {
|
|
panic("reflect: " + op + " of unexported method")
|
|
}
|
|
ifn := textOffFor(v.typ(), m.Ifn)
|
|
fn = unsafe.Pointer(&ifn)
|
|
t = (*funcType)(unsafe.Pointer(typeOffFor(v.typ(), m.Mtyp)))
|
|
}
|
|
return
|
|
}
|
|
|
|
// v is a method receiver. Store at p the word which is used to
|
|
// encode that receiver at the start of the argument list.
|
|
// Reflect uses the "interface" calling convention for
|
|
// methods, which always uses one word to record the receiver.
|
|
func storeRcvr(v Value, p unsafe.Pointer) {
|
|
t := v.typ()
|
|
if t.Kind() == abi.Interface {
|
|
// the interface data word becomes the receiver word
|
|
iface := (*nonEmptyInterface)(v.ptr)
|
|
*(*unsafe.Pointer)(p) = iface.word
|
|
} else if v.flag&flagIndir != 0 && !t.IfaceIndir() {
|
|
*(*unsafe.Pointer)(p) = *(*unsafe.Pointer)(v.ptr)
|
|
} else {
|
|
*(*unsafe.Pointer)(p) = v.ptr
|
|
}
|
|
}
|
|
|
|
// align returns the result of rounding x up to a multiple of n.
|
|
// n must be a power of two.
|
|
func align(x, n uintptr) uintptr {
|
|
return (x + n - 1) &^ (n - 1)
|
|
}
|
|
|
|
// callMethod is the call implementation used by a function returned
|
|
// by makeMethodValue (used by v.Method(i).Interface()).
|
|
// It is a streamlined version of the usual reflect call: the caller has
|
|
// already laid out the argument frame for us, so we don't have
|
|
// to deal with individual Values for each argument.
|
|
// It is in this file so that it can be next to the two similar functions above.
|
|
// The remainder of the makeMethodValue implementation is in makefunc.go.
|
|
//
|
|
// NOTE: This function must be marked as a "wrapper" in the generated code,
|
|
// so that the linker can make it work correctly for panic and recover.
|
|
// The gc compilers know to do that for the name "reflect.callMethod".
|
|
//
|
|
// ctxt is the "closure" generated by makeMethodValue.
|
|
// frame is a pointer to the arguments to that closure on the stack.
|
|
// retValid points to a boolean which should be set when the results
|
|
// section of frame is set.
|
|
//
|
|
// regs contains the argument values passed in registers and will contain
|
|
// the values returned from ctxt.fn in registers.
|
|
func callMethod(ctxt *methodValue, frame unsafe.Pointer, retValid *bool, regs *abi.RegArgs) {
|
|
rcvr := ctxt.rcvr
|
|
rcvrType, valueFuncType, methodFn := methodReceiver("call", rcvr, ctxt.method)
|
|
|
|
// There are two ABIs at play here.
|
|
//
|
|
// methodValueCall was invoked with the ABI assuming there was no
|
|
// receiver ("value ABI") and that's what frame and regs are holding.
|
|
//
|
|
// Meanwhile, we need to actually call the method with a receiver, which
|
|
// has its own ABI ("method ABI"). Everything that follows is a translation
|
|
// between the two.
|
|
_, _, valueABI := funcLayout(valueFuncType, nil)
|
|
valueFrame, valueRegs := frame, regs
|
|
methodFrameType, methodFramePool, methodABI := funcLayout(valueFuncType, rcvrType)
|
|
|
|
// Make a new frame that is one word bigger so we can store the receiver.
|
|
// This space is used for both arguments and return values.
|
|
methodFrame := methodFramePool.Get().(unsafe.Pointer)
|
|
var methodRegs abi.RegArgs
|
|
|
|
// Deal with the receiver. It's guaranteed to only be one word in size.
|
|
switch st := methodABI.call.steps[0]; st.kind {
|
|
case abiStepStack:
|
|
// Only copy the receiver to the stack if the ABI says so.
|
|
// Otherwise, it'll be in a register already.
|
|
storeRcvr(rcvr, methodFrame)
|
|
case abiStepPointer:
|
|
// Put the receiver in a register.
|
|
storeRcvr(rcvr, unsafe.Pointer(&methodRegs.Ptrs[st.ireg]))
|
|
fallthrough
|
|
case abiStepIntReg:
|
|
storeRcvr(rcvr, unsafe.Pointer(&methodRegs.Ints[st.ireg]))
|
|
case abiStepFloatReg:
|
|
storeRcvr(rcvr, unsafe.Pointer(&methodRegs.Floats[st.freg]))
|
|
default:
|
|
panic("unknown ABI parameter kind")
|
|
}
|
|
|
|
// Translate the rest of the arguments.
|
|
for i, t := range valueFuncType.InSlice() {
|
|
valueSteps := valueABI.call.stepsForValue(i)
|
|
methodSteps := methodABI.call.stepsForValue(i + 1)
|
|
|
|
// Zero-sized types are trivial: nothing to do.
|
|
if len(valueSteps) == 0 {
|
|
if len(methodSteps) != 0 {
|
|
panic("method ABI and value ABI do not align")
|
|
}
|
|
continue
|
|
}
|
|
|
|
// There are four cases to handle in translating each
|
|
// argument:
|
|
// 1. Stack -> stack translation.
|
|
// 2. Stack -> registers translation.
|
|
// 3. Registers -> stack translation.
|
|
// 4. Registers -> registers translation.
|
|
|
|
// If the value ABI passes the value on the stack,
|
|
// then the method ABI does too, because it has strictly
|
|
// fewer arguments. Simply copy between the two.
|
|
if vStep := valueSteps[0]; vStep.kind == abiStepStack {
|
|
mStep := methodSteps[0]
|
|
// Handle stack -> stack translation.
|
|
if mStep.kind == abiStepStack {
|
|
if vStep.size != mStep.size {
|
|
panic("method ABI and value ABI do not align")
|
|
}
|
|
typedmemmove(t,
|
|
add(methodFrame, mStep.stkOff, "precomputed stack offset"),
|
|
add(valueFrame, vStep.stkOff, "precomputed stack offset"))
|
|
continue
|
|
}
|
|
// Handle stack -> register translation.
|
|
for _, mStep := range methodSteps {
|
|
from := add(valueFrame, vStep.stkOff+mStep.offset, "precomputed stack offset")
|
|
switch mStep.kind {
|
|
case abiStepPointer:
|
|
// Do the pointer copy directly so we get a write barrier.
|
|
methodRegs.Ptrs[mStep.ireg] = *(*unsafe.Pointer)(from)
|
|
fallthrough // We need to make sure this ends up in Ints, too.
|
|
case abiStepIntReg:
|
|
intToReg(&methodRegs, mStep.ireg, mStep.size, from)
|
|
case abiStepFloatReg:
|
|
floatToReg(&methodRegs, mStep.freg, mStep.size, from)
|
|
default:
|
|
panic("unexpected method step")
|
|
}
|
|
}
|
|
continue
|
|
}
|
|
// Handle register -> stack translation.
|
|
if mStep := methodSteps[0]; mStep.kind == abiStepStack {
|
|
for _, vStep := range valueSteps {
|
|
to := add(methodFrame, mStep.stkOff+vStep.offset, "precomputed stack offset")
|
|
switch vStep.kind {
|
|
case abiStepPointer:
|
|
// Do the pointer copy directly so we get a write barrier.
|
|
*(*unsafe.Pointer)(to) = valueRegs.Ptrs[vStep.ireg]
|
|
case abiStepIntReg:
|
|
intFromReg(valueRegs, vStep.ireg, vStep.size, to)
|
|
case abiStepFloatReg:
|
|
floatFromReg(valueRegs, vStep.freg, vStep.size, to)
|
|
default:
|
|
panic("unexpected value step")
|
|
}
|
|
}
|
|
continue
|
|
}
|
|
// Handle register -> register translation.
|
|
if len(valueSteps) != len(methodSteps) {
|
|
// Because it's the same type for the value, and it's assigned
|
|
// to registers both times, it should always take up the same
|
|
// number of registers for each ABI.
|
|
panic("method ABI and value ABI don't align")
|
|
}
|
|
for i, vStep := range valueSteps {
|
|
mStep := methodSteps[i]
|
|
if mStep.kind != vStep.kind {
|
|
panic("method ABI and value ABI don't align")
|
|
}
|
|
switch vStep.kind {
|
|
case abiStepPointer:
|
|
// Copy this too, so we get a write barrier.
|
|
methodRegs.Ptrs[mStep.ireg] = valueRegs.Ptrs[vStep.ireg]
|
|
fallthrough
|
|
case abiStepIntReg:
|
|
methodRegs.Ints[mStep.ireg] = valueRegs.Ints[vStep.ireg]
|
|
case abiStepFloatReg:
|
|
methodRegs.Floats[mStep.freg] = valueRegs.Floats[vStep.freg]
|
|
default:
|
|
panic("unexpected value step")
|
|
}
|
|
}
|
|
}
|
|
|
|
methodFrameSize := methodFrameType.Size()
|
|
// TODO(mknyszek): Remove this when we no longer have
|
|
// caller reserved spill space.
|
|
methodFrameSize = align(methodFrameSize, goarch.PtrSize)
|
|
methodFrameSize += methodABI.spill
|
|
|
|
// Mark pointers in registers for the return path.
|
|
methodRegs.ReturnIsPtr = methodABI.outRegPtrs
|
|
|
|
// Call.
|
|
// Call copies the arguments from scratch to the stack, calls fn,
|
|
// and then copies the results back into scratch.
|
|
call(methodFrameType, methodFn, methodFrame, uint32(methodFrameType.Size()), uint32(methodABI.retOffset), uint32(methodFrameSize), &methodRegs)
|
|
|
|
// Copy return values.
|
|
//
|
|
// This is somewhat simpler because both ABIs have an identical
|
|
// return value ABI (the types are identical). As a result, register
|
|
// results can simply be copied over. Stack-allocated values are laid
|
|
// out the same, but are at different offsets from the start of the frame
|
|
// Ignore any changes to args.
|
|
// Avoid constructing out-of-bounds pointers if there are no return values.
|
|
// because the arguments may be laid out differently.
|
|
if valueRegs != nil {
|
|
*valueRegs = methodRegs
|
|
}
|
|
if retSize := methodFrameType.Size() - methodABI.retOffset; retSize > 0 {
|
|
valueRet := add(valueFrame, valueABI.retOffset, "valueFrame's size > retOffset")
|
|
methodRet := add(methodFrame, methodABI.retOffset, "methodFrame's size > retOffset")
|
|
// This copies to the stack. Write barriers are not needed.
|
|
memmove(valueRet, methodRet, retSize)
|
|
}
|
|
|
|
// Tell the runtime it can now depend on the return values
|
|
// being properly initialized.
|
|
*retValid = true
|
|
|
|
// Clear the scratch space and put it back in the pool.
|
|
// This must happen after the statement above, so that the return
|
|
// values will always be scanned by someone.
|
|
typedmemclr(methodFrameType, methodFrame)
|
|
methodFramePool.Put(methodFrame)
|
|
|
|
// See the comment in callReflect.
|
|
runtime.KeepAlive(ctxt)
|
|
|
|
// Keep valueRegs alive because it may hold live pointer results.
|
|
// The caller (methodValueCall) has it as a stack object, which is only
|
|
// scanned when there is a reference to it.
|
|
runtime.KeepAlive(valueRegs)
|
|
}
|
|
|
|
// funcName returns the name of f, for use in error messages.
|
|
func funcName(f func([]Value) []Value) string {
|
|
pc := *(*uintptr)(unsafe.Pointer(&f))
|
|
rf := runtime.FuncForPC(pc)
|
|
if rf != nil {
|
|
return rf.Name()
|
|
}
|
|
return "closure"
|
|
}
|
|
|
|
// Cap returns v's capacity.
|
|
// It panics if v's Kind is not [Array], [Chan], [Slice] or pointer to [Array].
|
|
func (v Value) Cap() int {
|
|
// capNonSlice is split out to keep Cap inlineable for slice kinds.
|
|
if v.kind() == Slice {
|
|
return (*unsafeheader.Slice)(v.ptr).Cap
|
|
}
|
|
return v.capNonSlice()
|
|
}
|
|
|
|
func (v Value) capNonSlice() int {
|
|
k := v.kind()
|
|
switch k {
|
|
case Array:
|
|
return v.typ().Len()
|
|
case Chan:
|
|
return chancap(v.pointer())
|
|
case Ptr:
|
|
if v.typ().Elem().Kind() == abi.Array {
|
|
return v.typ().Elem().Len()
|
|
}
|
|
panic("reflect: call of reflect.Value.Cap on ptr to non-array Value")
|
|
}
|
|
panic(&ValueError{"reflect.Value.Cap", v.kind()})
|
|
}
|
|
|
|
// Close closes the channel v.
|
|
// It panics if v's Kind is not [Chan] or
|
|
// v is a receive-only channel.
|
|
func (v Value) Close() {
|
|
v.mustBe(Chan)
|
|
v.mustBeExported()
|
|
tt := (*chanType)(unsafe.Pointer(v.typ()))
|
|
if ChanDir(tt.Dir)&SendDir == 0 {
|
|
panic("reflect: close of receive-only channel")
|
|
}
|
|
|
|
chanclose(v.pointer())
|
|
}
|
|
|
|
// CanComplex reports whether [Value.Complex] can be used without panicking.
|
|
func (v Value) CanComplex() bool {
|
|
switch v.kind() {
|
|
case Complex64, Complex128:
|
|
return true
|
|
default:
|
|
return false
|
|
}
|
|
}
|
|
|
|
// Complex returns v's underlying value, as a complex128.
|
|
// It panics if v's Kind is not [Complex64] or [Complex128]
|
|
func (v Value) Complex() complex128 {
|
|
k := v.kind()
|
|
switch k {
|
|
case Complex64:
|
|
return complex128(*(*complex64)(v.ptr))
|
|
case Complex128:
|
|
return *(*complex128)(v.ptr)
|
|
}
|
|
panic(&ValueError{"reflect.Value.Complex", v.kind()})
|
|
}
|
|
|
|
// Elem returns the value that the interface v contains
|
|
// or that the pointer v points to.
|
|
// It panics if v's Kind is not [Interface] or [Pointer].
|
|
// It returns the zero Value if v is nil.
|
|
func (v Value) Elem() Value {
|
|
k := v.kind()
|
|
switch k {
|
|
case Interface:
|
|
var eface any
|
|
if v.typ().NumMethod() == 0 {
|
|
eface = *(*any)(v.ptr)
|
|
} else {
|
|
eface = (any)(*(*interface {
|
|
M()
|
|
})(v.ptr))
|
|
}
|
|
x := unpackEface(eface)
|
|
if x.flag != 0 {
|
|
x.flag |= v.flag.ro()
|
|
}
|
|
return x
|
|
case Pointer:
|
|
ptr := v.ptr
|
|
if v.flag&flagIndir != 0 {
|
|
if v.typ().IfaceIndir() {
|
|
// This is a pointer to a not-in-heap object. ptr points to a uintptr
|
|
// in the heap. That uintptr is the address of a not-in-heap object.
|
|
// In general, pointers to not-in-heap objects can be total junk.
|
|
// But Elem() is asking to dereference it, so the user has asserted
|
|
// that at least it is a valid pointer (not just an integer stored in
|
|
// a pointer slot). So let's check, to make sure that it isn't a pointer
|
|
// that the runtime will crash on if it sees it during GC or write barriers.
|
|
// Since it is a not-in-heap pointer, all pointers to the heap are
|
|
// forbidden! That makes the test pretty easy.
|
|
// See issue 48399.
|
|
if !verifyNotInHeapPtr(*(*uintptr)(ptr)) {
|
|
panic("reflect: reflect.Value.Elem on an invalid notinheap pointer")
|
|
}
|
|
}
|
|
ptr = *(*unsafe.Pointer)(ptr)
|
|
}
|
|
// The returned value's address is v's value.
|
|
if ptr == nil {
|
|
return Value{}
|
|
}
|
|
tt := (*ptrType)(unsafe.Pointer(v.typ()))
|
|
typ := tt.Elem
|
|
fl := v.flag&flagRO | flagIndir | flagAddr
|
|
fl |= flag(typ.Kind())
|
|
return Value{typ, ptr, fl}
|
|
}
|
|
panic(&ValueError{"reflect.Value.Elem", v.kind()})
|
|
}
|
|
|
|
// Field returns the i'th field of the struct v.
|
|
// It panics if v's Kind is not [Struct] or i is out of range.
|
|
func (v Value) Field(i int) Value {
|
|
if v.kind() != Struct {
|
|
panic(&ValueError{"reflect.Value.Field", v.kind()})
|
|
}
|
|
tt := (*structType)(unsafe.Pointer(v.typ()))
|
|
if uint(i) >= uint(len(tt.Fields)) {
|
|
panic("reflect: Field index out of range")
|
|
}
|
|
field := &tt.Fields[i]
|
|
typ := field.Typ
|
|
|
|
// Inherit permission bits from v, but clear flagEmbedRO.
|
|
fl := v.flag&(flagStickyRO|flagIndir|flagAddr) | flag(typ.Kind())
|
|
// Using an unexported field forces flagRO.
|
|
if !field.Name.IsExported() {
|
|
if field.Embedded() {
|
|
fl |= flagEmbedRO
|
|
} else {
|
|
fl |= flagStickyRO
|
|
}
|
|
}
|
|
// Either flagIndir is set and v.ptr points at struct,
|
|
// or flagIndir is not set and v.ptr is the actual struct data.
|
|
// In the former case, we want v.ptr + offset.
|
|
// In the latter case, we must have field.offset = 0,
|
|
// so v.ptr + field.offset is still the correct address.
|
|
ptr := add(v.ptr, field.Offset, "same as non-reflect &v.field")
|
|
return Value{typ, ptr, fl}
|
|
}
|
|
|
|
// FieldByIndex returns the nested field corresponding to index.
|
|
// It panics if evaluation requires stepping through a nil
|
|
// pointer or a field that is not a struct.
|
|
func (v Value) FieldByIndex(index []int) Value {
|
|
if len(index) == 1 {
|
|
return v.Field(index[0])
|
|
}
|
|
v.mustBe(Struct)
|
|
for i, x := range index {
|
|
if i > 0 {
|
|
if v.Kind() == Pointer && v.typ().Elem().Kind() == abi.Struct {
|
|
if v.IsNil() {
|
|
panic("reflect: indirection through nil pointer to embedded struct")
|
|
}
|
|
v = v.Elem()
|
|
}
|
|
}
|
|
v = v.Field(x)
|
|
}
|
|
return v
|
|
}
|
|
|
|
// FieldByIndexErr returns the nested field corresponding to index.
|
|
// It returns an error if evaluation requires stepping through a nil
|
|
// pointer, but panics if it must step through a field that
|
|
// is not a struct.
|
|
func (v Value) FieldByIndexErr(index []int) (Value, error) {
|
|
if len(index) == 1 {
|
|
return v.Field(index[0]), nil
|
|
}
|
|
v.mustBe(Struct)
|
|
for i, x := range index {
|
|
if i > 0 {
|
|
if v.Kind() == Ptr && v.typ().Elem().Kind() == abi.Struct {
|
|
if v.IsNil() {
|
|
return Value{}, errors.New("reflect: indirection through nil pointer to embedded struct field " + nameFor(v.typ().Elem()))
|
|
}
|
|
v = v.Elem()
|
|
}
|
|
}
|
|
v = v.Field(x)
|
|
}
|
|
return v, nil
|
|
}
|
|
|
|
// FieldByName returns the struct field with the given name.
|
|
// It returns the zero Value if no field was found.
|
|
// It panics if v's Kind is not [Struct].
|
|
func (v Value) FieldByName(name string) Value {
|
|
v.mustBe(Struct)
|
|
if f, ok := toRType(v.typ()).FieldByName(name); ok {
|
|
return v.FieldByIndex(f.Index)
|
|
}
|
|
return Value{}
|
|
}
|
|
|
|
// FieldByNameFunc returns the struct field with a name
|
|
// that satisfies the match function.
|
|
// It panics if v's Kind is not [Struct].
|
|
// It returns the zero Value if no field was found.
|
|
func (v Value) FieldByNameFunc(match func(string) bool) Value {
|
|
if f, ok := toRType(v.typ()).FieldByNameFunc(match); ok {
|
|
return v.FieldByIndex(f.Index)
|
|
}
|
|
return Value{}
|
|
}
|
|
|
|
// CanFloat reports whether [Value.Float] can be used without panicking.
|
|
func (v Value) CanFloat() bool {
|
|
switch v.kind() {
|
|
case Float32, Float64:
|
|
return true
|
|
default:
|
|
return false
|
|
}
|
|
}
|
|
|
|
// Float returns v's underlying value, as a float64.
|
|
// It panics if v's Kind is not [Float32] or [Float64]
|
|
func (v Value) Float() float64 {
|
|
k := v.kind()
|
|
switch k {
|
|
case Float32:
|
|
return float64(*(*float32)(v.ptr))
|
|
case Float64:
|
|
return *(*float64)(v.ptr)
|
|
}
|
|
panic(&ValueError{"reflect.Value.Float", v.kind()})
|
|
}
|
|
|
|
var uint8Type = rtypeOf(uint8(0))
|
|
|
|
// Index returns v's i'th element.
|
|
// It panics if v's Kind is not [Array], [Slice], or [String] or i is out of range.
|
|
func (v Value) Index(i int) Value {
|
|
switch v.kind() {
|
|
case Array:
|
|
tt := (*arrayType)(unsafe.Pointer(v.typ()))
|
|
if uint(i) >= uint(tt.Len) {
|
|
panic("reflect: array index out of range")
|
|
}
|
|
typ := tt.Elem
|
|
offset := uintptr(i) * typ.Size()
|
|
|
|
// Either flagIndir is set and v.ptr points at array,
|
|
// or flagIndir is not set and v.ptr is the actual array data.
|
|
// In the former case, we want v.ptr + offset.
|
|
// In the latter case, we must be doing Index(0), so offset = 0,
|
|
// so v.ptr + offset is still the correct address.
|
|
val := add(v.ptr, offset, "same as &v[i], i < tt.len")
|
|
fl := v.flag&(flagIndir|flagAddr) | v.flag.ro() | flag(typ.Kind()) // bits same as overall array
|
|
return Value{typ, val, fl}
|
|
|
|
case Slice:
|
|
// Element flag same as Elem of Pointer.
|
|
// Addressable, indirect, possibly read-only.
|
|
s := (*unsafeheader.Slice)(v.ptr)
|
|
if uint(i) >= uint(s.Len) {
|
|
panic("reflect: slice index out of range")
|
|
}
|
|
tt := (*sliceType)(unsafe.Pointer(v.typ()))
|
|
typ := tt.Elem
|
|
val := arrayAt(s.Data, i, typ.Size(), "i < s.Len")
|
|
fl := flagAddr | flagIndir | v.flag.ro() | flag(typ.Kind())
|
|
return Value{typ, val, fl}
|
|
|
|
case String:
|
|
s := (*unsafeheader.String)(v.ptr)
|
|
if uint(i) >= uint(s.Len) {
|
|
panic("reflect: string index out of range")
|
|
}
|
|
p := arrayAt(s.Data, i, 1, "i < s.Len")
|
|
fl := v.flag.ro() | flag(Uint8) | flagIndir
|
|
return Value{uint8Type, p, fl}
|
|
}
|
|
panic(&ValueError{"reflect.Value.Index", v.kind()})
|
|
}
|
|
|
|
// CanInt reports whether Int can be used without panicking.
|
|
func (v Value) CanInt() bool {
|
|
switch v.kind() {
|
|
case Int, Int8, Int16, Int32, Int64:
|
|
return true
|
|
default:
|
|
return false
|
|
}
|
|
}
|
|
|
|
// Int returns v's underlying value, as an int64.
|
|
// It panics if v's Kind is not [Int], [Int8], [Int16], [Int32], or [Int64].
|
|
func (v Value) Int() int64 {
|
|
k := v.kind()
|
|
p := v.ptr
|
|
switch k {
|
|
case Int:
|
|
return int64(*(*int)(p))
|
|
case Int8:
|
|
return int64(*(*int8)(p))
|
|
case Int16:
|
|
return int64(*(*int16)(p))
|
|
case Int32:
|
|
return int64(*(*int32)(p))
|
|
case Int64:
|
|
return *(*int64)(p)
|
|
}
|
|
panic(&ValueError{"reflect.Value.Int", v.kind()})
|
|
}
|
|
|
|
// CanInterface reports whether [Value.Interface] can be used without panicking.
|
|
func (v Value) CanInterface() bool {
|
|
if v.flag == 0 {
|
|
panic(&ValueError{"reflect.Value.CanInterface", Invalid})
|
|
}
|
|
return v.flag&flagRO == 0
|
|
}
|
|
|
|
// Interface returns v's current value as an interface{}.
|
|
// It is equivalent to:
|
|
//
|
|
// var i interface{} = (v's underlying value)
|
|
//
|
|
// It panics if the Value was obtained by accessing
|
|
// unexported struct fields.
|
|
func (v Value) Interface() (i any) {
|
|
return valueInterface(v, true)
|
|
}
|
|
|
|
func valueInterface(v Value, safe bool) any {
|
|
if v.flag == 0 {
|
|
panic(&ValueError{"reflect.Value.Interface", Invalid})
|
|
}
|
|
if safe && v.flag&flagRO != 0 {
|
|
// Do not allow access to unexported values via Interface,
|
|
// because they might be pointers that should not be
|
|
// writable or methods or function that should not be callable.
|
|
panic("reflect.Value.Interface: cannot return value obtained from unexported field or method")
|
|
}
|
|
if v.flag&flagMethod != 0 {
|
|
v = makeMethodValue("Interface", v)
|
|
}
|
|
|
|
if v.kind() == Interface {
|
|
// Special case: return the element inside the interface.
|
|
// Empty interface has one layout, all interfaces with
|
|
// methods have a second layout.
|
|
if v.NumMethod() == 0 {
|
|
return *(*any)(v.ptr)
|
|
}
|
|
return *(*interface {
|
|
M()
|
|
})(v.ptr)
|
|
}
|
|
|
|
return packEface(v)
|
|
}
|
|
|
|
// InterfaceData returns a pair of unspecified uintptr values.
|
|
// It panics if v's Kind is not Interface.
|
|
//
|
|
// In earlier versions of Go, this function returned the interface's
|
|
// value as a uintptr pair. As of Go 1.4, the implementation of
|
|
// interface values precludes any defined use of InterfaceData.
|
|
//
|
|
// Deprecated: The memory representation of interface values is not
|
|
// compatible with InterfaceData.
|
|
func (v Value) InterfaceData() [2]uintptr {
|
|
v.mustBe(Interface)
|
|
// The compiler loses track as it converts to uintptr. Force escape.
|
|
escapes(v.ptr)
|
|
// We treat this as a read operation, so we allow
|
|
// it even for unexported data, because the caller
|
|
// has to import "unsafe" to turn it into something
|
|
// that can be abused.
|
|
// Interface value is always bigger than a word; assume flagIndir.
|
|
return *(*[2]uintptr)(v.ptr)
|
|
}
|
|
|
|
// IsNil reports whether its argument v is nil. The argument must be
|
|
// a chan, func, interface, map, pointer, or slice value; if it is
|
|
// not, IsNil panics. Note that IsNil is not always equivalent to a
|
|
// regular comparison with nil in Go. For example, if v was created
|
|
// by calling [ValueOf] with an uninitialized interface variable i,
|
|
// i==nil will be true but v.IsNil will panic as v will be the zero
|
|
// Value.
|
|
func (v Value) IsNil() bool {
|
|
k := v.kind()
|
|
switch k {
|
|
case Chan, Func, Map, Pointer, UnsafePointer:
|
|
if v.flag&flagMethod != 0 {
|
|
return false
|
|
}
|
|
ptr := v.ptr
|
|
if v.flag&flagIndir != 0 {
|
|
ptr = *(*unsafe.Pointer)(ptr)
|
|
}
|
|
return ptr == nil
|
|
case Interface, Slice:
|
|
// Both interface and slice are nil if first word is 0.
|
|
// Both are always bigger than a word; assume flagIndir.
|
|
return *(*unsafe.Pointer)(v.ptr) == nil
|
|
}
|
|
panic(&ValueError{"reflect.Value.IsNil", v.kind()})
|
|
}
|
|
|
|
// IsValid reports whether v represents a value.
|
|
// It returns false if v is the zero Value.
|
|
// If [Value.IsValid] returns false, all other methods except String panic.
|
|
// Most functions and methods never return an invalid Value.
|
|
// If one does, its documentation states the conditions explicitly.
|
|
func (v Value) IsValid() bool {
|
|
return v.flag != 0
|
|
}
|
|
|
|
// IsZero reports whether v is the zero value for its type.
|
|
// It panics if the argument is invalid.
|
|
func (v Value) IsZero() bool {
|
|
switch v.kind() {
|
|
case Bool:
|
|
return !v.Bool()
|
|
case Int, Int8, Int16, Int32, Int64:
|
|
return v.Int() == 0
|
|
case Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
|
|
return v.Uint() == 0
|
|
case Float32, Float64:
|
|
return v.Float() == 0
|
|
case Complex64, Complex128:
|
|
return v.Complex() == 0
|
|
case Array:
|
|
if v.flag&flagIndir == 0 {
|
|
return v.ptr == nil
|
|
}
|
|
typ := (*abi.ArrayType)(unsafe.Pointer(v.typ()))
|
|
// If the type is comparable, then compare directly with zero.
|
|
if typ.Equal != nil && typ.Size() <= abi.ZeroValSize {
|
|
// v.ptr doesn't escape, as Equal functions are compiler generated
|
|
// and never escape. The escape analysis doesn't know, as it is a
|
|
// function pointer call.
|
|
return typ.Equal(abi.NoEscape(v.ptr), unsafe.Pointer(&abi.ZeroVal[0]))
|
|
}
|
|
if typ.TFlag&abi.TFlagRegularMemory != 0 {
|
|
// For some types where the zero value is a value where all bits of this type are 0
|
|
// optimize it.
|
|
return isZero(unsafe.Slice(((*byte)(v.ptr)), typ.Size()))
|
|
}
|
|
n := int(typ.Len)
|
|
for i := 0; i < n; i++ {
|
|
if !v.Index(i).IsZero() {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
case Chan, Func, Interface, Map, Pointer, Slice, UnsafePointer:
|
|
return v.IsNil()
|
|
case String:
|
|
return v.Len() == 0
|
|
case Struct:
|
|
if v.flag&flagIndir == 0 {
|
|
return v.ptr == nil
|
|
}
|
|
typ := (*abi.StructType)(unsafe.Pointer(v.typ()))
|
|
// If the type is comparable, then compare directly with zero.
|
|
if typ.Equal != nil && typ.Size() <= abi.ZeroValSize {
|
|
// See noescape justification above.
|
|
return typ.Equal(abi.NoEscape(v.ptr), unsafe.Pointer(&abi.ZeroVal[0]))
|
|
}
|
|
if typ.TFlag&abi.TFlagRegularMemory != 0 {
|
|
// For some types where the zero value is a value where all bits of this type are 0
|
|
// optimize it.
|
|
return isZero(unsafe.Slice(((*byte)(v.ptr)), typ.Size()))
|
|
}
|
|
|
|
n := v.NumField()
|
|
for i := 0; i < n; i++ {
|
|
if !v.Field(i).IsZero() && v.Type().Field(i).Name != "_" {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
default:
|
|
// This should never happen, but will act as a safeguard for later,
|
|
// as a default value doesn't makes sense here.
|
|
panic(&ValueError{"reflect.Value.IsZero", v.Kind()})
|
|
}
|
|
}
|
|
|
|
// isZero For all zeros, performance is not as good as
|
|
// return bytealg.Count(b, byte(0)) == len(b)
|
|
func isZero(b []byte) bool {
|
|
if len(b) == 0 {
|
|
return true
|
|
}
|
|
const n = 32
|
|
// Align memory addresses to 8 bytes.
|
|
for uintptr(unsafe.Pointer(&b[0]))%8 != 0 {
|
|
if b[0] != 0 {
|
|
return false
|
|
}
|
|
b = b[1:]
|
|
if len(b) == 0 {
|
|
return true
|
|
}
|
|
}
|
|
for len(b)%8 != 0 {
|
|
if b[len(b)-1] != 0 {
|
|
return false
|
|
}
|
|
b = b[:len(b)-1]
|
|
}
|
|
if len(b) == 0 {
|
|
return true
|
|
}
|
|
w := unsafe.Slice((*uint64)(unsafe.Pointer(&b[0])), len(b)/8)
|
|
for len(w)%n != 0 {
|
|
if w[0] != 0 {
|
|
return false
|
|
}
|
|
w = w[1:]
|
|
}
|
|
for len(w) >= n {
|
|
if w[0] != 0 || w[1] != 0 || w[2] != 0 || w[3] != 0 ||
|
|
w[4] != 0 || w[5] != 0 || w[6] != 0 || w[7] != 0 ||
|
|
w[8] != 0 || w[9] != 0 || w[10] != 0 || w[11] != 0 ||
|
|
w[12] != 0 || w[13] != 0 || w[14] != 0 || w[15] != 0 ||
|
|
w[16] != 0 || w[17] != 0 || w[18] != 0 || w[19] != 0 ||
|
|
w[20] != 0 || w[21] != 0 || w[22] != 0 || w[23] != 0 ||
|
|
w[24] != 0 || w[25] != 0 || w[26] != 0 || w[27] != 0 ||
|
|
w[28] != 0 || w[29] != 0 || w[30] != 0 || w[31] != 0 {
|
|
return false
|
|
}
|
|
w = w[n:]
|
|
}
|
|
return true
|
|
}
|
|
|
|
// SetZero sets v to be the zero value of v's type.
|
|
// It panics if [Value.CanSet] returns false.
|
|
func (v Value) SetZero() {
|
|
v.mustBeAssignable()
|
|
switch v.kind() {
|
|
case Bool:
|
|
*(*bool)(v.ptr) = false
|
|
case Int:
|
|
*(*int)(v.ptr) = 0
|
|
case Int8:
|
|
*(*int8)(v.ptr) = 0
|
|
case Int16:
|
|
*(*int16)(v.ptr) = 0
|
|
case Int32:
|
|
*(*int32)(v.ptr) = 0
|
|
case Int64:
|
|
*(*int64)(v.ptr) = 0
|
|
case Uint:
|
|
*(*uint)(v.ptr) = 0
|
|
case Uint8:
|
|
*(*uint8)(v.ptr) = 0
|
|
case Uint16:
|
|
*(*uint16)(v.ptr) = 0
|
|
case Uint32:
|
|
*(*uint32)(v.ptr) = 0
|
|
case Uint64:
|
|
*(*uint64)(v.ptr) = 0
|
|
case Uintptr:
|
|
*(*uintptr)(v.ptr) = 0
|
|
case Float32:
|
|
*(*float32)(v.ptr) = 0
|
|
case Float64:
|
|
*(*float64)(v.ptr) = 0
|
|
case Complex64:
|
|
*(*complex64)(v.ptr) = 0
|
|
case Complex128:
|
|
*(*complex128)(v.ptr) = 0
|
|
case String:
|
|
*(*string)(v.ptr) = ""
|
|
case Slice:
|
|
*(*unsafeheader.Slice)(v.ptr) = unsafeheader.Slice{}
|
|
case Interface:
|
|
*(*abi.EmptyInterface)(v.ptr) = abi.EmptyInterface{}
|
|
case Chan, Func, Map, Pointer, UnsafePointer:
|
|
*(*unsafe.Pointer)(v.ptr) = nil
|
|
case Array, Struct:
|
|
typedmemclr(v.typ(), v.ptr)
|
|
default:
|
|
// This should never happen, but will act as a safeguard for later,
|
|
// as a default value doesn't makes sense here.
|
|
panic(&ValueError{"reflect.Value.SetZero", v.Kind()})
|
|
}
|
|
}
|
|
|
|
// Kind returns v's Kind.
|
|
// If v is the zero Value ([Value.IsValid] returns false), Kind returns Invalid.
|
|
func (v Value) Kind() Kind {
|
|
return v.kind()
|
|
}
|
|
|
|
// Len returns v's length.
|
|
// It panics if v's Kind is not [Array], [Chan], [Map], [Slice], [String], or pointer to [Array].
|
|
func (v Value) Len() int {
|
|
// lenNonSlice is split out to keep Len inlineable for slice kinds.
|
|
if v.kind() == Slice {
|
|
return (*unsafeheader.Slice)(v.ptr).Len
|
|
}
|
|
return v.lenNonSlice()
|
|
}
|
|
|
|
func (v Value) lenNonSlice() int {
|
|
switch k := v.kind(); k {
|
|
case Array:
|
|
tt := (*arrayType)(unsafe.Pointer(v.typ()))
|
|
return int(tt.Len)
|
|
case Chan:
|
|
return chanlen(v.pointer())
|
|
case Map:
|
|
return maplen(v.pointer())
|
|
case String:
|
|
// String is bigger than a word; assume flagIndir.
|
|
return (*unsafeheader.String)(v.ptr).Len
|
|
case Ptr:
|
|
if v.typ().Elem().Kind() == abi.Array {
|
|
return v.typ().Elem().Len()
|
|
}
|
|
panic("reflect: call of reflect.Value.Len on ptr to non-array Value")
|
|
}
|
|
panic(&ValueError{"reflect.Value.Len", v.kind()})
|
|
}
|
|
|
|
var stringType = rtypeOf("")
|
|
|
|
// MapIndex returns the value associated with key in the map v.
|
|
// It panics if v's Kind is not [Map].
|
|
// It returns the zero Value if key is not found in the map or if v represents a nil map.
|
|
// As in Go, the key's value must be assignable to the map's key type.
|
|
func (v Value) MapIndex(key Value) Value {
|
|
v.mustBe(Map)
|
|
tt := (*mapType)(unsafe.Pointer(v.typ()))
|
|
|
|
// Do not require key to be exported, so that DeepEqual
|
|
// and other programs can use all the keys returned by
|
|
// MapKeys as arguments to MapIndex. If either the map
|
|
// or the key is unexported, though, the result will be
|
|
// considered unexported. This is consistent with the
|
|
// behavior for structs, which allow read but not write
|
|
// of unexported fields.
|
|
|
|
var e unsafe.Pointer
|
|
if (tt.Key == stringType || key.kind() == String) && tt.Key == key.typ() && tt.Elem.Size() <= abi.MapMaxElemBytes {
|
|
k := *(*string)(key.ptr)
|
|
e = mapaccess_faststr(v.typ(), v.pointer(), k)
|
|
} else {
|
|
key = key.assignTo("reflect.Value.MapIndex", tt.Key, nil)
|
|
var k unsafe.Pointer
|
|
if key.flag&flagIndir != 0 {
|
|
k = key.ptr
|
|
} else {
|
|
k = unsafe.Pointer(&key.ptr)
|
|
}
|
|
e = mapaccess(v.typ(), v.pointer(), k)
|
|
}
|
|
if e == nil {
|
|
return Value{}
|
|
}
|
|
typ := tt.Elem
|
|
fl := (v.flag | key.flag).ro()
|
|
fl |= flag(typ.Kind())
|
|
return copyVal(typ, fl, e)
|
|
}
|
|
|
|
// MapKeys returns a slice containing all the keys present in the map,
|
|
// in unspecified order.
|
|
// It panics if v's Kind is not [Map].
|
|
// It returns an empty slice if v represents a nil map.
|
|
func (v Value) MapKeys() []Value {
|
|
v.mustBe(Map)
|
|
tt := (*mapType)(unsafe.Pointer(v.typ()))
|
|
keyType := tt.Key
|
|
|
|
fl := v.flag.ro() | flag(keyType.Kind())
|
|
|
|
m := v.pointer()
|
|
mlen := int(0)
|
|
if m != nil {
|
|
mlen = maplen(m)
|
|
}
|
|
var it hiter
|
|
mapiterinit(v.typ(), m, &it)
|
|
a := make([]Value, mlen)
|
|
var i int
|
|
for i = 0; i < len(a); i++ {
|
|
key := mapiterkey(&it)
|
|
if key == nil {
|
|
// Someone deleted an entry from the map since we
|
|
// called maplen above. It's a data race, but nothing
|
|
// we can do about it.
|
|
break
|
|
}
|
|
a[i] = copyVal(keyType, fl, key)
|
|
mapiternext(&it)
|
|
}
|
|
return a[:i]
|
|
}
|
|
|
|
// hiter's structure matches runtime.hiter's structure.
|
|
// Having a clone here allows us to embed a map iterator
|
|
// inside type MapIter so that MapIters can be re-used
|
|
// without doing any allocations.
|
|
type hiter struct {
|
|
key unsafe.Pointer
|
|
elem unsafe.Pointer
|
|
t unsafe.Pointer
|
|
h unsafe.Pointer
|
|
buckets unsafe.Pointer
|
|
bptr unsafe.Pointer
|
|
overflow *[]unsafe.Pointer
|
|
oldoverflow *[]unsafe.Pointer
|
|
startBucket uintptr
|
|
offset uint8
|
|
wrapped bool
|
|
B uint8
|
|
i uint8
|
|
bucket uintptr
|
|
checkBucket uintptr
|
|
}
|
|
|
|
func (h *hiter) initialized() bool {
|
|
return h.t != nil
|
|
}
|
|
|
|
// A MapIter is an iterator for ranging over a map.
|
|
// See [Value.MapRange].
|
|
type MapIter struct {
|
|
m Value
|
|
hiter hiter
|
|
}
|
|
|
|
// Key returns the key of iter's current map entry.
|
|
func (iter *MapIter) Key() Value {
|
|
if !iter.hiter.initialized() {
|
|
panic("MapIter.Key called before Next")
|
|
}
|
|
iterkey := mapiterkey(&iter.hiter)
|
|
if iterkey == nil {
|
|
panic("MapIter.Key called on exhausted iterator")
|
|
}
|
|
|
|
t := (*mapType)(unsafe.Pointer(iter.m.typ()))
|
|
ktype := t.Key
|
|
return copyVal(ktype, iter.m.flag.ro()|flag(ktype.Kind()), iterkey)
|
|
}
|
|
|
|
// SetIterKey assigns to v the key of iter's current map entry.
|
|
// It is equivalent to v.Set(iter.Key()), but it avoids allocating a new Value.
|
|
// As in Go, the key must be assignable to v's type and
|
|
// must not be derived from an unexported field.
|
|
func (v Value) SetIterKey(iter *MapIter) {
|
|
if !iter.hiter.initialized() {
|
|
panic("reflect: Value.SetIterKey called before Next")
|
|
}
|
|
iterkey := mapiterkey(&iter.hiter)
|
|
if iterkey == nil {
|
|
panic("reflect: Value.SetIterKey called on exhausted iterator")
|
|
}
|
|
|
|
v.mustBeAssignable()
|
|
var target unsafe.Pointer
|
|
if v.kind() == Interface {
|
|
target = v.ptr
|
|
}
|
|
|
|
t := (*mapType)(unsafe.Pointer(iter.m.typ()))
|
|
ktype := t.Key
|
|
|
|
iter.m.mustBeExported() // do not let unexported m leak
|
|
key := Value{ktype, iterkey, iter.m.flag | flag(ktype.Kind()) | flagIndir}
|
|
key = key.assignTo("reflect.MapIter.SetKey", v.typ(), target)
|
|
typedmemmove(v.typ(), v.ptr, key.ptr)
|
|
}
|
|
|
|
// Value returns the value of iter's current map entry.
|
|
func (iter *MapIter) Value() Value {
|
|
if !iter.hiter.initialized() {
|
|
panic("MapIter.Value called before Next")
|
|
}
|
|
iterelem := mapiterelem(&iter.hiter)
|
|
if iterelem == nil {
|
|
panic("MapIter.Value called on exhausted iterator")
|
|
}
|
|
|
|
t := (*mapType)(unsafe.Pointer(iter.m.typ()))
|
|
vtype := t.Elem
|
|
return copyVal(vtype, iter.m.flag.ro()|flag(vtype.Kind()), iterelem)
|
|
}
|
|
|
|
// SetIterValue assigns to v the value of iter's current map entry.
|
|
// It is equivalent to v.Set(iter.Value()), but it avoids allocating a new Value.
|
|
// As in Go, the value must be assignable to v's type and
|
|
// must not be derived from an unexported field.
|
|
func (v Value) SetIterValue(iter *MapIter) {
|
|
if !iter.hiter.initialized() {
|
|
panic("reflect: Value.SetIterValue called before Next")
|
|
}
|
|
iterelem := mapiterelem(&iter.hiter)
|
|
if iterelem == nil {
|
|
panic("reflect: Value.SetIterValue called on exhausted iterator")
|
|
}
|
|
|
|
v.mustBeAssignable()
|
|
var target unsafe.Pointer
|
|
if v.kind() == Interface {
|
|
target = v.ptr
|
|
}
|
|
|
|
t := (*mapType)(unsafe.Pointer(iter.m.typ()))
|
|
vtype := t.Elem
|
|
|
|
iter.m.mustBeExported() // do not let unexported m leak
|
|
elem := Value{vtype, iterelem, iter.m.flag | flag(vtype.Kind()) | flagIndir}
|
|
elem = elem.assignTo("reflect.MapIter.SetValue", v.typ(), target)
|
|
typedmemmove(v.typ(), v.ptr, elem.ptr)
|
|
}
|
|
|
|
// Next advances the map iterator and reports whether there is another
|
|
// entry. It returns false when iter is exhausted; subsequent
|
|
// calls to [MapIter.Key], [MapIter.Value], or [MapIter.Next] will panic.
|
|
func (iter *MapIter) Next() bool {
|
|
if !iter.m.IsValid() {
|
|
panic("MapIter.Next called on an iterator that does not have an associated map Value")
|
|
}
|
|
if !iter.hiter.initialized() {
|
|
mapiterinit(iter.m.typ(), iter.m.pointer(), &iter.hiter)
|
|
} else {
|
|
if mapiterkey(&iter.hiter) == nil {
|
|
panic("MapIter.Next called on exhausted iterator")
|
|
}
|
|
mapiternext(&iter.hiter)
|
|
}
|
|
return mapiterkey(&iter.hiter) != nil
|
|
}
|
|
|
|
// Reset modifies iter to iterate over v.
|
|
// It panics if v's Kind is not [Map] and v is not the zero Value.
|
|
// Reset(Value{}) causes iter to not to refer to any map,
|
|
// which may allow the previously iterated-over map to be garbage collected.
|
|
func (iter *MapIter) Reset(v Value) {
|
|
if v.IsValid() {
|
|
v.mustBe(Map)
|
|
}
|
|
iter.m = v
|
|
iter.hiter = hiter{}
|
|
}
|
|
|
|
// MapRange returns a range iterator for a map.
|
|
// It panics if v's Kind is not [Map].
|
|
//
|
|
// Call [MapIter.Next] to advance the iterator, and [MapIter.Key]/[MapIter.Value] to access each entry.
|
|
// [MapIter.Next] returns false when the iterator is exhausted.
|
|
// MapRange follows the same iteration semantics as a range statement.
|
|
//
|
|
// Example:
|
|
//
|
|
// iter := reflect.ValueOf(m).MapRange()
|
|
// for iter.Next() {
|
|
// k := iter.Key()
|
|
// v := iter.Value()
|
|
// ...
|
|
// }
|
|
func (v Value) MapRange() *MapIter {
|
|
// This is inlinable to take advantage of "function outlining".
|
|
// The allocation of MapIter can be stack allocated if the caller
|
|
// does not allow it to escape.
|
|
// See https://blog.filippo.io/efficient-go-apis-with-the-inliner/
|
|
if v.kind() != Map {
|
|
v.panicNotMap()
|
|
}
|
|
return &MapIter{m: v}
|
|
}
|
|
|
|
// Force slow panicking path not inlined, so it won't add to the
|
|
// inlining budget of the caller.
|
|
// TODO: undo when the inliner is no longer bottom-up only.
|
|
//
|
|
//go:noinline
|
|
func (f flag) panicNotMap() {
|
|
f.mustBe(Map)
|
|
}
|
|
|
|
// copyVal returns a Value containing the map key or value at ptr,
|
|
// allocating a new variable as needed.
|
|
func copyVal(typ *abi.Type, fl flag, ptr unsafe.Pointer) Value {
|
|
if typ.IfaceIndir() {
|
|
// Copy result so future changes to the map
|
|
// won't change the underlying value.
|
|
c := unsafe_New(typ)
|
|
typedmemmove(typ, c, ptr)
|
|
return Value{typ, c, fl | flagIndir}
|
|
}
|
|
return Value{typ, *(*unsafe.Pointer)(ptr), fl}
|
|
}
|
|
|
|
// Method returns a function value corresponding to v's i'th method.
|
|
// The arguments to a Call on the returned function should not include
|
|
// a receiver; the returned function will always use v as the receiver.
|
|
// Method panics if i is out of range or if v is a nil interface value.
|
|
func (v Value) Method(i int) Value {
|
|
if v.typ() == nil {
|
|
panic(&ValueError{"reflect.Value.Method", Invalid})
|
|
}
|
|
if v.flag&flagMethod != 0 || uint(i) >= uint(toRType(v.typ()).NumMethod()) {
|
|
panic("reflect: Method index out of range")
|
|
}
|
|
if v.typ().Kind() == abi.Interface && v.IsNil() {
|
|
panic("reflect: Method on nil interface value")
|
|
}
|
|
fl := v.flag.ro() | (v.flag & flagIndir)
|
|
fl |= flag(Func)
|
|
fl |= flag(i)<<flagMethodShift | flagMethod
|
|
return Value{v.typ(), v.ptr, fl}
|
|
}
|
|
|
|
// NumMethod returns the number of methods in the value's method set.
|
|
//
|
|
// For a non-interface type, it returns the number of exported methods.
|
|
//
|
|
// For an interface type, it returns the number of exported and unexported methods.
|
|
func (v Value) NumMethod() int {
|
|
if v.typ() == nil {
|
|
panic(&ValueError{"reflect.Value.NumMethod", Invalid})
|
|
}
|
|
if v.flag&flagMethod != 0 {
|
|
return 0
|
|
}
|
|
return toRType(v.typ()).NumMethod()
|
|
}
|
|
|
|
// MethodByName returns a function value corresponding to the method
|
|
// of v with the given name.
|
|
// The arguments to a Call on the returned function should not include
|
|
// a receiver; the returned function will always use v as the receiver.
|
|
// It returns the zero Value if no method was found.
|
|
func (v Value) MethodByName(name string) Value {
|
|
if v.typ() == nil {
|
|
panic(&ValueError{"reflect.Value.MethodByName", Invalid})
|
|
}
|
|
if v.flag&flagMethod != 0 {
|
|
return Value{}
|
|
}
|
|
m, ok := toRType(v.typ()).MethodByName(name)
|
|
if !ok {
|
|
return Value{}
|
|
}
|
|
return v.Method(m.Index)
|
|
}
|
|
|
|
// NumField returns the number of fields in the struct v.
|
|
// It panics if v's Kind is not [Struct].
|
|
func (v Value) NumField() int {
|
|
v.mustBe(Struct)
|
|
tt := (*structType)(unsafe.Pointer(v.typ()))
|
|
return len(tt.Fields)
|
|
}
|
|
|
|
// OverflowComplex reports whether the complex128 x cannot be represented by v's type.
|
|
// It panics if v's Kind is not [Complex64] or [Complex128].
|
|
func (v Value) OverflowComplex(x complex128) bool {
|
|
k := v.kind()
|
|
switch k {
|
|
case Complex64:
|
|
return overflowFloat32(real(x)) || overflowFloat32(imag(x))
|
|
case Complex128:
|
|
return false
|
|
}
|
|
panic(&ValueError{"reflect.Value.OverflowComplex", v.kind()})
|
|
}
|
|
|
|
// OverflowFloat reports whether the float64 x cannot be represented by v's type.
|
|
// It panics if v's Kind is not [Float32] or [Float64].
|
|
func (v Value) OverflowFloat(x float64) bool {
|
|
k := v.kind()
|
|
switch k {
|
|
case Float32:
|
|
return overflowFloat32(x)
|
|
case Float64:
|
|
return false
|
|
}
|
|
panic(&ValueError{"reflect.Value.OverflowFloat", v.kind()})
|
|
}
|
|
|
|
func overflowFloat32(x float64) bool {
|
|
if x < 0 {
|
|
x = -x
|
|
}
|
|
return math.MaxFloat32 < x && x <= math.MaxFloat64
|
|
}
|
|
|
|
// OverflowInt reports whether the int64 x cannot be represented by v's type.
|
|
// It panics if v's Kind is not [Int], [Int8], [Int16], [Int32], or [Int64].
|
|
func (v Value) OverflowInt(x int64) bool {
|
|
k := v.kind()
|
|
switch k {
|
|
case Int, Int8, Int16, Int32, Int64:
|
|
bitSize := v.typ().Size() * 8
|
|
trunc := (x << (64 - bitSize)) >> (64 - bitSize)
|
|
return x != trunc
|
|
}
|
|
panic(&ValueError{"reflect.Value.OverflowInt", v.kind()})
|
|
}
|
|
|
|
// OverflowUint reports whether the uint64 x cannot be represented by v's type.
|
|
// It panics if v's Kind is not [Uint], [Uintptr], [Uint8], [Uint16], [Uint32], or [Uint64].
|
|
func (v Value) OverflowUint(x uint64) bool {
|
|
k := v.kind()
|
|
switch k {
|
|
case Uint, Uintptr, Uint8, Uint16, Uint32, Uint64:
|
|
bitSize := v.typ_.Size() * 8 // ok to use v.typ_ directly as Size doesn't escape
|
|
trunc := (x << (64 - bitSize)) >> (64 - bitSize)
|
|
return x != trunc
|
|
}
|
|
panic(&ValueError{"reflect.Value.OverflowUint", v.kind()})
|
|
}
|
|
|
|
//go:nocheckptr
|
|
// This prevents inlining Value.Pointer when -d=checkptr is enabled,
|
|
// which ensures cmd/compile can recognize unsafe.Pointer(v.Pointer())
|
|
// and make an exception.
|
|
|
|
// Pointer returns v's value as a uintptr.
|
|
// It panics if v's Kind is not [Chan], [Func], [Map], [Pointer], [Slice], [String], or [UnsafePointer].
|
|
//
|
|
// If v's Kind is [Func], the returned pointer is an underlying
|
|
// code pointer, but not necessarily enough to identify a
|
|
// single function uniquely. The only guarantee is that the
|
|
// result is zero if and only if v is a nil func Value.
|
|
//
|
|
// If v's Kind is [Slice], the returned pointer is to the first
|
|
// element of the slice. If the slice is nil the returned value
|
|
// is 0. If the slice is empty but non-nil the return value is non-zero.
|
|
//
|
|
// If v's Kind is [String], the returned pointer is to the first
|
|
// element of the underlying bytes of string.
|
|
//
|
|
// It's preferred to use uintptr(Value.UnsafePointer()) to get the equivalent result.
|
|
func (v Value) Pointer() uintptr {
|
|
// The compiler loses track as it converts to uintptr. Force escape.
|
|
escapes(v.ptr)
|
|
|
|
k := v.kind()
|
|
switch k {
|
|
case Pointer:
|
|
if !v.typ().Pointers() {
|
|
val := *(*uintptr)(v.ptr)
|
|
// Since it is a not-in-heap pointer, all pointers to the heap are
|
|
// forbidden! See comment in Value.Elem and issue #48399.
|
|
if !verifyNotInHeapPtr(val) {
|
|
panic("reflect: reflect.Value.Pointer on an invalid notinheap pointer")
|
|
}
|
|
return val
|
|
}
|
|
fallthrough
|
|
case Chan, Map, UnsafePointer:
|
|
return uintptr(v.pointer())
|
|
case Func:
|
|
if v.flag&flagMethod != 0 {
|
|
// As the doc comment says, the returned pointer is an
|
|
// underlying code pointer but not necessarily enough to
|
|
// identify a single function uniquely. All method expressions
|
|
// created via reflect have the same underlying code pointer,
|
|
// so their Pointers are equal. The function used here must
|
|
// match the one used in makeMethodValue.
|
|
return methodValueCallCodePtr()
|
|
}
|
|
p := v.pointer()
|
|
// Non-nil func value points at data block.
|
|
// First word of data block is actual code.
|
|
if p != nil {
|
|
p = *(*unsafe.Pointer)(p)
|
|
}
|
|
return uintptr(p)
|
|
case Slice:
|
|
return uintptr((*unsafeheader.Slice)(v.ptr).Data)
|
|
case String:
|
|
return uintptr((*unsafeheader.String)(v.ptr).Data)
|
|
}
|
|
panic(&ValueError{"reflect.Value.Pointer", v.kind()})
|
|
}
|
|
|
|
// Recv receives and returns a value from the channel v.
|
|
// It panics if v's Kind is not [Chan].
|
|
// The receive blocks until a value is ready.
|
|
// The boolean value ok is true if the value x corresponds to a send
|
|
// on the channel, false if it is a zero value received because the channel is closed.
|
|
func (v Value) Recv() (x Value, ok bool) {
|
|
v.mustBe(Chan)
|
|
v.mustBeExported()
|
|
return v.recv(false)
|
|
}
|
|
|
|
// internal recv, possibly non-blocking (nb).
|
|
// v is known to be a channel.
|
|
func (v Value) recv(nb bool) (val Value, ok bool) {
|
|
tt := (*chanType)(unsafe.Pointer(v.typ()))
|
|
if ChanDir(tt.Dir)&RecvDir == 0 {
|
|
panic("reflect: recv on send-only channel")
|
|
}
|
|
t := tt.Elem
|
|
val = Value{t, nil, flag(t.Kind())}
|
|
var p unsafe.Pointer
|
|
if t.IfaceIndir() {
|
|
p = unsafe_New(t)
|
|
val.ptr = p
|
|
val.flag |= flagIndir
|
|
} else {
|
|
p = unsafe.Pointer(&val.ptr)
|
|
}
|
|
selected, ok := chanrecv(v.pointer(), nb, p)
|
|
if !selected {
|
|
val = Value{}
|
|
}
|
|
return
|
|
}
|
|
|
|
// Send sends x on the channel v.
|
|
// It panics if v's kind is not [Chan] or if x's type is not the same type as v's element type.
|
|
// As in Go, x's value must be assignable to the channel's element type.
|
|
func (v Value) Send(x Value) {
|
|
v.mustBe(Chan)
|
|
v.mustBeExported()
|
|
v.send(x, false)
|
|
}
|
|
|
|
// internal send, possibly non-blocking.
|
|
// v is known to be a channel.
|
|
func (v Value) send(x Value, nb bool) (selected bool) {
|
|
tt := (*chanType)(unsafe.Pointer(v.typ()))
|
|
if ChanDir(tt.Dir)&SendDir == 0 {
|
|
panic("reflect: send on recv-only channel")
|
|
}
|
|
x.mustBeExported()
|
|
x = x.assignTo("reflect.Value.Send", tt.Elem, nil)
|
|
var p unsafe.Pointer
|
|
if x.flag&flagIndir != 0 {
|
|
p = x.ptr
|
|
} else {
|
|
p = unsafe.Pointer(&x.ptr)
|
|
}
|
|
return chansend(v.pointer(), p, nb)
|
|
}
|
|
|
|
// Set assigns x to the value v.
|
|
// It panics if [Value.CanSet] returns false.
|
|
// As in Go, x's value must be assignable to v's type and
|
|
// must not be derived from an unexported field.
|
|
func (v Value) Set(x Value) {
|
|
v.mustBeAssignable()
|
|
x.mustBeExported() // do not let unexported x leak
|
|
var target unsafe.Pointer
|
|
if v.kind() == Interface {
|
|
target = v.ptr
|
|
}
|
|
x = x.assignTo("reflect.Set", v.typ(), target)
|
|
if x.flag&flagIndir != 0 {
|
|
if x.ptr == unsafe.Pointer(&abi.ZeroVal[0]) {
|
|
typedmemclr(v.typ(), v.ptr)
|
|
} else {
|
|
typedmemmove(v.typ(), v.ptr, x.ptr)
|
|
}
|
|
} else {
|
|
*(*unsafe.Pointer)(v.ptr) = x.ptr
|
|
}
|
|
}
|
|
|
|
// SetBool sets v's underlying value.
|
|
// It panics if v's Kind is not [Bool] or if [Value.CanSet] returns false.
|
|
func (v Value) SetBool(x bool) {
|
|
v.mustBeAssignable()
|
|
v.mustBe(Bool)
|
|
*(*bool)(v.ptr) = x
|
|
}
|
|
|
|
// SetBytes sets v's underlying value.
|
|
// It panics if v's underlying value is not a slice of bytes.
|
|
func (v Value) SetBytes(x []byte) {
|
|
v.mustBeAssignable()
|
|
v.mustBe(Slice)
|
|
if toRType(v.typ()).Elem().Kind() != Uint8 { // TODO add Elem method, fix mustBe(Slice) to return slice.
|
|
panic("reflect.Value.SetBytes of non-byte slice")
|
|
}
|
|
*(*[]byte)(v.ptr) = x
|
|
}
|
|
|
|
// setRunes sets v's underlying value.
|
|
// It panics if v's underlying value is not a slice of runes (int32s).
|
|
func (v Value) setRunes(x []rune) {
|
|
v.mustBeAssignable()
|
|
v.mustBe(Slice)
|
|
if v.typ().Elem().Kind() != abi.Int32 {
|
|
panic("reflect.Value.setRunes of non-rune slice")
|
|
}
|
|
*(*[]rune)(v.ptr) = x
|
|
}
|
|
|
|
// SetComplex sets v's underlying value to x.
|
|
// It panics if v's Kind is not [Complex64] or [Complex128], or if [Value.CanSet] returns false.
|
|
func (v Value) SetComplex(x complex128) {
|
|
v.mustBeAssignable()
|
|
switch k := v.kind(); k {
|
|
default:
|
|
panic(&ValueError{"reflect.Value.SetComplex", v.kind()})
|
|
case Complex64:
|
|
*(*complex64)(v.ptr) = complex64(x)
|
|
case Complex128:
|
|
*(*complex128)(v.ptr) = x
|
|
}
|
|
}
|
|
|
|
// SetFloat sets v's underlying value to x.
|
|
// It panics if v's Kind is not [Float32] or [Float64], or if [Value.CanSet] returns false.
|
|
func (v Value) SetFloat(x float64) {
|
|
v.mustBeAssignable()
|
|
switch k := v.kind(); k {
|
|
default:
|
|
panic(&ValueError{"reflect.Value.SetFloat", v.kind()})
|
|
case Float32:
|
|
*(*float32)(v.ptr) = float32(x)
|
|
case Float64:
|
|
*(*float64)(v.ptr) = x
|
|
}
|
|
}
|
|
|
|
// SetInt sets v's underlying value to x.
|
|
// It panics if v's Kind is not [Int], [Int8], [Int16], [Int32], or [Int64], or if [Value.CanSet] returns false.
|
|
func (v Value) SetInt(x int64) {
|
|
v.mustBeAssignable()
|
|
switch k := v.kind(); k {
|
|
default:
|
|
panic(&ValueError{"reflect.Value.SetInt", v.kind()})
|
|
case Int:
|
|
*(*int)(v.ptr) = int(x)
|
|
case Int8:
|
|
*(*int8)(v.ptr) = int8(x)
|
|
case Int16:
|
|
*(*int16)(v.ptr) = int16(x)
|
|
case Int32:
|
|
*(*int32)(v.ptr) = int32(x)
|
|
case Int64:
|
|
*(*int64)(v.ptr) = x
|
|
}
|
|
}
|
|
|
|
// SetLen sets v's length to n.
|
|
// It panics if v's Kind is not [Slice] or if n is negative or
|
|
// greater than the capacity of the slice.
|
|
func (v Value) SetLen(n int) {
|
|
v.mustBeAssignable()
|
|
v.mustBe(Slice)
|
|
s := (*unsafeheader.Slice)(v.ptr)
|
|
if uint(n) > uint(s.Cap) {
|
|
panic("reflect: slice length out of range in SetLen")
|
|
}
|
|
s.Len = n
|
|
}
|
|
|
|
// SetCap sets v's capacity to n.
|
|
// It panics if v's Kind is not [Slice] or if n is smaller than the length or
|
|
// greater than the capacity of the slice.
|
|
func (v Value) SetCap(n int) {
|
|
v.mustBeAssignable()
|
|
v.mustBe(Slice)
|
|
s := (*unsafeheader.Slice)(v.ptr)
|
|
if n < s.Len || n > s.Cap {
|
|
panic("reflect: slice capacity out of range in SetCap")
|
|
}
|
|
s.Cap = n
|
|
}
|
|
|
|
// SetMapIndex sets the element associated with key in the map v to elem.
|
|
// It panics if v's Kind is not [Map].
|
|
// If elem is the zero Value, SetMapIndex deletes the key from the map.
|
|
// Otherwise if v holds a nil map, SetMapIndex will panic.
|
|
// As in Go, key's elem must be assignable to the map's key type,
|
|
// and elem's value must be assignable to the map's elem type.
|
|
func (v Value) SetMapIndex(key, elem Value) {
|
|
v.mustBe(Map)
|
|
v.mustBeExported()
|
|
key.mustBeExported()
|
|
tt := (*mapType)(unsafe.Pointer(v.typ()))
|
|
|
|
if (tt.Key == stringType || key.kind() == String) && tt.Key == key.typ() && tt.Elem.Size() <= abi.MapMaxElemBytes {
|
|
k := *(*string)(key.ptr)
|
|
if elem.typ() == nil {
|
|
mapdelete_faststr(v.typ(), v.pointer(), k)
|
|
return
|
|
}
|
|
elem.mustBeExported()
|
|
elem = elem.assignTo("reflect.Value.SetMapIndex", tt.Elem, nil)
|
|
var e unsafe.Pointer
|
|
if elem.flag&flagIndir != 0 {
|
|
e = elem.ptr
|
|
} else {
|
|
e = unsafe.Pointer(&elem.ptr)
|
|
}
|
|
mapassign_faststr(v.typ(), v.pointer(), k, e)
|
|
return
|
|
}
|
|
|
|
key = key.assignTo("reflect.Value.SetMapIndex", tt.Key, nil)
|
|
var k unsafe.Pointer
|
|
if key.flag&flagIndir != 0 {
|
|
k = key.ptr
|
|
} else {
|
|
k = unsafe.Pointer(&key.ptr)
|
|
}
|
|
if elem.typ() == nil {
|
|
mapdelete(v.typ(), v.pointer(), k)
|
|
return
|
|
}
|
|
elem.mustBeExported()
|
|
elem = elem.assignTo("reflect.Value.SetMapIndex", tt.Elem, nil)
|
|
var e unsafe.Pointer
|
|
if elem.flag&flagIndir != 0 {
|
|
e = elem.ptr
|
|
} else {
|
|
e = unsafe.Pointer(&elem.ptr)
|
|
}
|
|
mapassign(v.typ(), v.pointer(), k, e)
|
|
}
|
|
|
|
// SetUint sets v's underlying value to x.
|
|
// It panics if v's Kind is not [Uint], [Uintptr], [Uint8], [Uint16], [Uint32], or [Uint64], or if [Value.CanSet] returns false.
|
|
func (v Value) SetUint(x uint64) {
|
|
v.mustBeAssignable()
|
|
switch k := v.kind(); k {
|
|
default:
|
|
panic(&ValueError{"reflect.Value.SetUint", v.kind()})
|
|
case Uint:
|
|
*(*uint)(v.ptr) = uint(x)
|
|
case Uint8:
|
|
*(*uint8)(v.ptr) = uint8(x)
|
|
case Uint16:
|
|
*(*uint16)(v.ptr) = uint16(x)
|
|
case Uint32:
|
|
*(*uint32)(v.ptr) = uint32(x)
|
|
case Uint64:
|
|
*(*uint64)(v.ptr) = x
|
|
case Uintptr:
|
|
*(*uintptr)(v.ptr) = uintptr(x)
|
|
}
|
|
}
|
|
|
|
// SetPointer sets the [unsafe.Pointer] value v to x.
|
|
// It panics if v's Kind is not [UnsafePointer].
|
|
func (v Value) SetPointer(x unsafe.Pointer) {
|
|
v.mustBeAssignable()
|
|
v.mustBe(UnsafePointer)
|
|
*(*unsafe.Pointer)(v.ptr) = x
|
|
}
|
|
|
|
// SetString sets v's underlying value to x.
|
|
// It panics if v's Kind is not [String] or if [Value.CanSet] returns false.
|
|
func (v Value) SetString(x string) {
|
|
v.mustBeAssignable()
|
|
v.mustBe(String)
|
|
*(*string)(v.ptr) = x
|
|
}
|
|
|
|
// Slice returns v[i:j].
|
|
// It panics if v's Kind is not [Array], [Slice] or [String], or if v is an unaddressable array,
|
|
// or if the indexes are out of bounds.
|
|
func (v Value) Slice(i, j int) Value {
|
|
var (
|
|
cap int
|
|
typ *sliceType
|
|
base unsafe.Pointer
|
|
)
|
|
switch kind := v.kind(); kind {
|
|
default:
|
|
panic(&ValueError{"reflect.Value.Slice", v.kind()})
|
|
|
|
case Array:
|
|
if v.flag&flagAddr == 0 {
|
|
panic("reflect.Value.Slice: slice of unaddressable array")
|
|
}
|
|
tt := (*arrayType)(unsafe.Pointer(v.typ()))
|
|
cap = int(tt.Len)
|
|
typ = (*sliceType)(unsafe.Pointer(tt.Slice))
|
|
base = v.ptr
|
|
|
|
case Slice:
|
|
typ = (*sliceType)(unsafe.Pointer(v.typ()))
|
|
s := (*unsafeheader.Slice)(v.ptr)
|
|
base = s.Data
|
|
cap = s.Cap
|
|
|
|
case String:
|
|
s := (*unsafeheader.String)(v.ptr)
|
|
if i < 0 || j < i || j > s.Len {
|
|
panic("reflect.Value.Slice: string slice index out of bounds")
|
|
}
|
|
var t unsafeheader.String
|
|
if i < s.Len {
|
|
t = unsafeheader.String{Data: arrayAt(s.Data, i, 1, "i < s.Len"), Len: j - i}
|
|
}
|
|
return Value{v.typ(), unsafe.Pointer(&t), v.flag}
|
|
}
|
|
|
|
if i < 0 || j < i || j > cap {
|
|
panic("reflect.Value.Slice: slice index out of bounds")
|
|
}
|
|
|
|
// Declare slice so that gc can see the base pointer in it.
|
|
var x []unsafe.Pointer
|
|
|
|
// Reinterpret as *unsafeheader.Slice to edit.
|
|
s := (*unsafeheader.Slice)(unsafe.Pointer(&x))
|
|
s.Len = j - i
|
|
s.Cap = cap - i
|
|
if cap-i > 0 {
|
|
s.Data = arrayAt(base, i, typ.Elem.Size(), "i < cap")
|
|
} else {
|
|
// do not advance pointer, to avoid pointing beyond end of slice
|
|
s.Data = base
|
|
}
|
|
|
|
fl := v.flag.ro() | flagIndir | flag(Slice)
|
|
return Value{typ.Common(), unsafe.Pointer(&x), fl}
|
|
}
|
|
|
|
// Slice3 is the 3-index form of the slice operation: it returns v[i:j:k].
|
|
// It panics if v's Kind is not [Array] or [Slice], or if v is an unaddressable array,
|
|
// or if the indexes are out of bounds.
|
|
func (v Value) Slice3(i, j, k int) Value {
|
|
var (
|
|
cap int
|
|
typ *sliceType
|
|
base unsafe.Pointer
|
|
)
|
|
switch kind := v.kind(); kind {
|
|
default:
|
|
panic(&ValueError{"reflect.Value.Slice3", v.kind()})
|
|
|
|
case Array:
|
|
if v.flag&flagAddr == 0 {
|
|
panic("reflect.Value.Slice3: slice of unaddressable array")
|
|
}
|
|
tt := (*arrayType)(unsafe.Pointer(v.typ()))
|
|
cap = int(tt.Len)
|
|
typ = (*sliceType)(unsafe.Pointer(tt.Slice))
|
|
base = v.ptr
|
|
|
|
case Slice:
|
|
typ = (*sliceType)(unsafe.Pointer(v.typ()))
|
|
s := (*unsafeheader.Slice)(v.ptr)
|
|
base = s.Data
|
|
cap = s.Cap
|
|
}
|
|
|
|
if i < 0 || j < i || k < j || k > cap {
|
|
panic("reflect.Value.Slice3: slice index out of bounds")
|
|
}
|
|
|
|
// Declare slice so that the garbage collector
|
|
// can see the base pointer in it.
|
|
var x []unsafe.Pointer
|
|
|
|
// Reinterpret as *unsafeheader.Slice to edit.
|
|
s := (*unsafeheader.Slice)(unsafe.Pointer(&x))
|
|
s.Len = j - i
|
|
s.Cap = k - i
|
|
if k-i > 0 {
|
|
s.Data = arrayAt(base, i, typ.Elem.Size(), "i < k <= cap")
|
|
} else {
|
|
// do not advance pointer, to avoid pointing beyond end of slice
|
|
s.Data = base
|
|
}
|
|
|
|
fl := v.flag.ro() | flagIndir | flag(Slice)
|
|
return Value{typ.Common(), unsafe.Pointer(&x), fl}
|
|
}
|
|
|
|
// String returns the string v's underlying value, as a string.
|
|
// String is a special case because of Go's String method convention.
|
|
// Unlike the other getters, it does not panic if v's Kind is not [String].
|
|
// Instead, it returns a string of the form "<T value>" where T is v's type.
|
|
// The fmt package treats Values specially. It does not call their String
|
|
// method implicitly but instead prints the concrete values they hold.
|
|
func (v Value) String() string {
|
|
// stringNonString is split out to keep String inlineable for string kinds.
|
|
if v.kind() == String {
|
|
return *(*string)(v.ptr)
|
|
}
|
|
return v.stringNonString()
|
|
}
|
|
|
|
func (v Value) stringNonString() string {
|
|
if v.kind() == Invalid {
|
|
return "<invalid Value>"
|
|
}
|
|
// If you call String on a reflect.Value of other type, it's better to
|
|
// print something than to panic. Useful in debugging.
|
|
return "<" + v.Type().String() + " Value>"
|
|
}
|
|
|
|
// TryRecv attempts to receive a value from the channel v but will not block.
|
|
// It panics if v's Kind is not [Chan].
|
|
// If the receive delivers a value, x is the transferred value and ok is true.
|
|
// If the receive cannot finish without blocking, x is the zero Value and ok is false.
|
|
// If the channel is closed, x is the zero value for the channel's element type and ok is false.
|
|
func (v Value) TryRecv() (x Value, ok bool) {
|
|
v.mustBe(Chan)
|
|
v.mustBeExported()
|
|
return v.recv(true)
|
|
}
|
|
|
|
// TrySend attempts to send x on the channel v but will not block.
|
|
// It panics if v's Kind is not [Chan].
|
|
// It reports whether the value was sent.
|
|
// As in Go, x's value must be assignable to the channel's element type.
|
|
func (v Value) TrySend(x Value) bool {
|
|
v.mustBe(Chan)
|
|
v.mustBeExported()
|
|
return v.send(x, true)
|
|
}
|
|
|
|
// Type returns v's type.
|
|
func (v Value) Type() Type {
|
|
if v.flag != 0 && v.flag&flagMethod == 0 {
|
|
return (*rtype)(noescape(unsafe.Pointer(v.typ_))) // inline of toRType(v.typ()), for own inlining in inline test
|
|
}
|
|
return v.typeSlow()
|
|
}
|
|
|
|
func (v Value) typeSlow() Type {
|
|
if v.flag == 0 {
|
|
panic(&ValueError{"reflect.Value.Type", Invalid})
|
|
}
|
|
|
|
typ := v.typ()
|
|
if v.flag&flagMethod == 0 {
|
|
return toRType(v.typ())
|
|
}
|
|
|
|
// Method value.
|
|
// v.typ describes the receiver, not the method type.
|
|
i := int(v.flag) >> flagMethodShift
|
|
if v.typ().Kind() == abi.Interface {
|
|
// Method on interface.
|
|
tt := (*interfaceType)(unsafe.Pointer(typ))
|
|
if uint(i) >= uint(len(tt.Methods)) {
|
|
panic("reflect: internal error: invalid method index")
|
|
}
|
|
m := &tt.Methods[i]
|
|
return toRType(typeOffFor(typ, m.Typ))
|
|
}
|
|
// Method on concrete type.
|
|
ms := typ.ExportedMethods()
|
|
if uint(i) >= uint(len(ms)) {
|
|
panic("reflect: internal error: invalid method index")
|
|
}
|
|
m := ms[i]
|
|
return toRType(typeOffFor(typ, m.Mtyp))
|
|
}
|
|
|
|
// CanUint reports whether [Value.Uint] can be used without panicking.
|
|
func (v Value) CanUint() bool {
|
|
switch v.kind() {
|
|
case Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
|
|
return true
|
|
default:
|
|
return false
|
|
}
|
|
}
|
|
|
|
// Uint returns v's underlying value, as a uint64.
|
|
// It panics if v's Kind is not [Uint], [Uintptr], [Uint8], [Uint16], [Uint32], or [Uint64].
|
|
func (v Value) Uint() uint64 {
|
|
k := v.kind()
|
|
p := v.ptr
|
|
switch k {
|
|
case Uint:
|
|
return uint64(*(*uint)(p))
|
|
case Uint8:
|
|
return uint64(*(*uint8)(p))
|
|
case Uint16:
|
|
return uint64(*(*uint16)(p))
|
|
case Uint32:
|
|
return uint64(*(*uint32)(p))
|
|
case Uint64:
|
|
return *(*uint64)(p)
|
|
case Uintptr:
|
|
return uint64(*(*uintptr)(p))
|
|
}
|
|
panic(&ValueError{"reflect.Value.Uint", v.kind()})
|
|
}
|
|
|
|
//go:nocheckptr
|
|
// This prevents inlining Value.UnsafeAddr when -d=checkptr is enabled,
|
|
// which ensures cmd/compile can recognize unsafe.Pointer(v.UnsafeAddr())
|
|
// and make an exception.
|
|
|
|
// UnsafeAddr returns a pointer to v's data, as a uintptr.
|
|
// It panics if v is not addressable.
|
|
//
|
|
// It's preferred to use uintptr(Value.Addr().UnsafePointer()) to get the equivalent result.
|
|
func (v Value) UnsafeAddr() uintptr {
|
|
if v.typ() == nil {
|
|
panic(&ValueError{"reflect.Value.UnsafeAddr", Invalid})
|
|
}
|
|
if v.flag&flagAddr == 0 {
|
|
panic("reflect.Value.UnsafeAddr of unaddressable value")
|
|
}
|
|
// The compiler loses track as it converts to uintptr. Force escape.
|
|
escapes(v.ptr)
|
|
return uintptr(v.ptr)
|
|
}
|
|
|
|
// UnsafePointer returns v's value as a [unsafe.Pointer].
|
|
// It panics if v's Kind is not [Chan], [Func], [Map], [Pointer], [Slice], [String] or [UnsafePointer].
|
|
//
|
|
// If v's Kind is [Func], the returned pointer is an underlying
|
|
// code pointer, but not necessarily enough to identify a
|
|
// single function uniquely. The only guarantee is that the
|
|
// result is zero if and only if v is a nil func Value.
|
|
//
|
|
// If v's Kind is [Slice], the returned pointer is to the first
|
|
// element of the slice. If the slice is nil the returned value
|
|
// is nil. If the slice is empty but non-nil the return value is non-nil.
|
|
//
|
|
// If v's Kind is [String], the returned pointer is to the first
|
|
// element of the underlying bytes of string.
|
|
func (v Value) UnsafePointer() unsafe.Pointer {
|
|
k := v.kind()
|
|
switch k {
|
|
case Pointer:
|
|
if !v.typ().Pointers() {
|
|
// Since it is a not-in-heap pointer, all pointers to the heap are
|
|
// forbidden! See comment in Value.Elem and issue #48399.
|
|
if !verifyNotInHeapPtr(*(*uintptr)(v.ptr)) {
|
|
panic("reflect: reflect.Value.UnsafePointer on an invalid notinheap pointer")
|
|
}
|
|
return *(*unsafe.Pointer)(v.ptr)
|
|
}
|
|
fallthrough
|
|
case Chan, Map, UnsafePointer:
|
|
return v.pointer()
|
|
case Func:
|
|
if v.flag&flagMethod != 0 {
|
|
// As the doc comment says, the returned pointer is an
|
|
// underlying code pointer but not necessarily enough to
|
|
// identify a single function uniquely. All method expressions
|
|
// created via reflect have the same underlying code pointer,
|
|
// so their Pointers are equal. The function used here must
|
|
// match the one used in makeMethodValue.
|
|
code := methodValueCallCodePtr()
|
|
return *(*unsafe.Pointer)(unsafe.Pointer(&code))
|
|
}
|
|
p := v.pointer()
|
|
// Non-nil func value points at data block.
|
|
// First word of data block is actual code.
|
|
if p != nil {
|
|
p = *(*unsafe.Pointer)(p)
|
|
}
|
|
return p
|
|
case Slice:
|
|
return (*unsafeheader.Slice)(v.ptr).Data
|
|
case String:
|
|
return (*unsafeheader.String)(v.ptr).Data
|
|
}
|
|
panic(&ValueError{"reflect.Value.UnsafePointer", v.kind()})
|
|
}
|
|
|
|
// StringHeader is the runtime representation of a string.
|
|
// It cannot be used safely or portably and its representation may
|
|
// change in a later release.
|
|
// Moreover, the Data field is not sufficient to guarantee the data
|
|
// it references will not be garbage collected, so programs must keep
|
|
// a separate, correctly typed pointer to the underlying data.
|
|
//
|
|
// Deprecated: Use unsafe.String or unsafe.StringData instead.
|
|
type StringHeader struct {
|
|
Data uintptr
|
|
Len int
|
|
}
|
|
|
|
// SliceHeader is the runtime representation of a slice.
|
|
// It cannot be used safely or portably and its representation may
|
|
// change in a later release.
|
|
// Moreover, the Data field is not sufficient to guarantee the data
|
|
// it references will not be garbage collected, so programs must keep
|
|
// a separate, correctly typed pointer to the underlying data.
|
|
//
|
|
// Deprecated: Use unsafe.Slice or unsafe.SliceData instead.
|
|
type SliceHeader struct {
|
|
Data uintptr
|
|
Len int
|
|
Cap int
|
|
}
|
|
|
|
func typesMustMatch(what string, t1, t2 Type) {
|
|
if t1 != t2 {
|
|
panic(what + ": " + t1.String() + " != " + t2.String())
|
|
}
|
|
}
|
|
|
|
// arrayAt returns the i-th element of p,
|
|
// an array whose elements are eltSize bytes wide.
|
|
// The array pointed at by p must have at least i+1 elements:
|
|
// it is invalid (but impossible to check here) to pass i >= len,
|
|
// because then the result will point outside the array.
|
|
// whySafe must explain why i < len. (Passing "i < len" is fine;
|
|
// the benefit is to surface this assumption at the call site.)
|
|
func arrayAt(p unsafe.Pointer, i int, eltSize uintptr, whySafe string) unsafe.Pointer {
|
|
return add(p, uintptr(i)*eltSize, "i < len")
|
|
}
|
|
|
|
// Grow increases the slice's capacity, if necessary, to guarantee space for
|
|
// another n elements. After Grow(n), at least n elements can be appended
|
|
// to the slice without another allocation.
|
|
//
|
|
// It panics if v's Kind is not a [Slice] or if n is negative or too large to
|
|
// allocate the memory.
|
|
func (v Value) Grow(n int) {
|
|
v.mustBeAssignable()
|
|
v.mustBe(Slice)
|
|
v.grow(n)
|
|
}
|
|
|
|
// grow is identical to Grow but does not check for assignability.
|
|
func (v Value) grow(n int) {
|
|
p := (*unsafeheader.Slice)(v.ptr)
|
|
switch {
|
|
case n < 0:
|
|
panic("reflect.Value.Grow: negative len")
|
|
case p.Len+n < 0:
|
|
panic("reflect.Value.Grow: slice overflow")
|
|
case p.Len+n > p.Cap:
|
|
t := v.typ().Elem()
|
|
*p = growslice(t, *p, n)
|
|
}
|
|
}
|
|
|
|
// extendSlice extends a slice by n elements.
|
|
//
|
|
// Unlike Value.grow, which modifies the slice in place and
|
|
// does not change the length of the slice in place,
|
|
// extendSlice returns a new slice value with the length
|
|
// incremented by the number of specified elements.
|
|
func (v Value) extendSlice(n int) Value {
|
|
v.mustBeExported()
|
|
v.mustBe(Slice)
|
|
|
|
// Shallow copy the slice header to avoid mutating the source slice.
|
|
sh := *(*unsafeheader.Slice)(v.ptr)
|
|
s := &sh
|
|
v.ptr = unsafe.Pointer(s)
|
|
v.flag = flagIndir | flag(Slice) // equivalent flag to MakeSlice
|
|
|
|
v.grow(n) // fine to treat as assignable since we allocate a new slice header
|
|
s.Len += n
|
|
return v
|
|
}
|
|
|
|
// Clear clears the contents of a map or zeros the contents of a slice.
|
|
//
|
|
// It panics if v's Kind is not [Map] or [Slice].
|
|
func (v Value) Clear() {
|
|
switch v.Kind() {
|
|
case Slice:
|
|
sh := *(*unsafeheader.Slice)(v.ptr)
|
|
st := (*sliceType)(unsafe.Pointer(v.typ()))
|
|
typedarrayclear(st.Elem, sh.Data, sh.Len)
|
|
case Map:
|
|
mapclear(v.typ(), v.pointer())
|
|
default:
|
|
panic(&ValueError{"reflect.Value.Clear", v.Kind()})
|
|
}
|
|
}
|
|
|
|
// Append appends the values x to a slice s and returns the resulting slice.
|
|
// As in Go, each x's value must be assignable to the slice's element type.
|
|
func Append(s Value, x ...Value) Value {
|
|
s.mustBe(Slice)
|
|
n := s.Len()
|
|
s = s.extendSlice(len(x))
|
|
for i, v := range x {
|
|
s.Index(n + i).Set(v)
|
|
}
|
|
return s
|
|
}
|
|
|
|
// AppendSlice appends a slice t to a slice s and returns the resulting slice.
|
|
// The slices s and t must have the same element type.
|
|
func AppendSlice(s, t Value) Value {
|
|
s.mustBe(Slice)
|
|
t.mustBe(Slice)
|
|
typesMustMatch("reflect.AppendSlice", s.Type().Elem(), t.Type().Elem())
|
|
ns := s.Len()
|
|
nt := t.Len()
|
|
s = s.extendSlice(nt)
|
|
Copy(s.Slice(ns, ns+nt), t)
|
|
return s
|
|
}
|
|
|
|
// Copy copies the contents of src into dst until either
|
|
// dst has been filled or src has been exhausted.
|
|
// It returns the number of elements copied.
|
|
// Dst and src each must have kind [Slice] or [Array], and
|
|
// dst and src must have the same element type.
|
|
//
|
|
// As a special case, src can have kind [String] if the element type of dst is kind [Uint8].
|
|
func Copy(dst, src Value) int {
|
|
dk := dst.kind()
|
|
if dk != Array && dk != Slice {
|
|
panic(&ValueError{"reflect.Copy", dk})
|
|
}
|
|
if dk == Array {
|
|
dst.mustBeAssignable()
|
|
}
|
|
dst.mustBeExported()
|
|
|
|
sk := src.kind()
|
|
var stringCopy bool
|
|
if sk != Array && sk != Slice {
|
|
stringCopy = sk == String && dst.typ().Elem().Kind() == abi.Uint8
|
|
if !stringCopy {
|
|
panic(&ValueError{"reflect.Copy", sk})
|
|
}
|
|
}
|
|
src.mustBeExported()
|
|
|
|
de := dst.typ().Elem()
|
|
if !stringCopy {
|
|
se := src.typ().Elem()
|
|
typesMustMatch("reflect.Copy", toType(de), toType(se))
|
|
}
|
|
|
|
var ds, ss unsafeheader.Slice
|
|
if dk == Array {
|
|
ds.Data = dst.ptr
|
|
ds.Len = dst.Len()
|
|
ds.Cap = ds.Len
|
|
} else {
|
|
ds = *(*unsafeheader.Slice)(dst.ptr)
|
|
}
|
|
if sk == Array {
|
|
ss.Data = src.ptr
|
|
ss.Len = src.Len()
|
|
ss.Cap = ss.Len
|
|
} else if sk == Slice {
|
|
ss = *(*unsafeheader.Slice)(src.ptr)
|
|
} else {
|
|
sh := *(*unsafeheader.String)(src.ptr)
|
|
ss.Data = sh.Data
|
|
ss.Len = sh.Len
|
|
ss.Cap = sh.Len
|
|
}
|
|
|
|
return typedslicecopy(de.Common(), ds, ss)
|
|
}
|
|
|
|
// A runtimeSelect is a single case passed to rselect.
|
|
// This must match ../runtime/select.go:/runtimeSelect
|
|
type runtimeSelect struct {
|
|
dir SelectDir // SelectSend, SelectRecv or SelectDefault
|
|
typ *rtype // channel type
|
|
ch unsafe.Pointer // channel
|
|
val unsafe.Pointer // ptr to data (SendDir) or ptr to receive buffer (RecvDir)
|
|
}
|
|
|
|
// rselect runs a select. It returns the index of the chosen case.
|
|
// If the case was a receive, val is filled in with the received value.
|
|
// The conventional OK bool indicates whether the receive corresponds
|
|
// to a sent value.
|
|
//
|
|
// rselect generally doesn't escape the runtimeSelect slice, except
|
|
// that for the send case the value to send needs to escape. We don't
|
|
// have a way to represent that in the function signature. So we handle
|
|
// that with a forced escape in function Select.
|
|
//
|
|
//go:noescape
|
|
func rselect([]runtimeSelect) (chosen int, recvOK bool)
|
|
|
|
// A SelectDir describes the communication direction of a select case.
|
|
type SelectDir int
|
|
|
|
// NOTE: These values must match ../runtime/select.go:/selectDir.
|
|
|
|
const (
|
|
_ SelectDir = iota
|
|
SelectSend // case Chan <- Send
|
|
SelectRecv // case <-Chan:
|
|
SelectDefault // default
|
|
)
|
|
|
|
// A SelectCase describes a single case in a select operation.
|
|
// The kind of case depends on Dir, the communication direction.
|
|
//
|
|
// If Dir is SelectDefault, the case represents a default case.
|
|
// Chan and Send must be zero Values.
|
|
//
|
|
// If Dir is SelectSend, the case represents a send operation.
|
|
// Normally Chan's underlying value must be a channel, and Send's underlying value must be
|
|
// assignable to the channel's element type. As a special case, if Chan is a zero Value,
|
|
// then the case is ignored, and the field Send will also be ignored and may be either zero
|
|
// or non-zero.
|
|
//
|
|
// If Dir is [SelectRecv], the case represents a receive operation.
|
|
// Normally Chan's underlying value must be a channel and Send must be a zero Value.
|
|
// If Chan is a zero Value, then the case is ignored, but Send must still be a zero Value.
|
|
// When a receive operation is selected, the received Value is returned by Select.
|
|
type SelectCase struct {
|
|
Dir SelectDir // direction of case
|
|
Chan Value // channel to use (for send or receive)
|
|
Send Value // value to send (for send)
|
|
}
|
|
|
|
// Select executes a select operation described by the list of cases.
|
|
// Like the Go select statement, it blocks until at least one of the cases
|
|
// can proceed, makes a uniform pseudo-random choice,
|
|
// and then executes that case. It returns the index of the chosen case
|
|
// and, if that case was a receive operation, the value received and a
|
|
// boolean indicating whether the value corresponds to a send on the channel
|
|
// (as opposed to a zero value received because the channel is closed).
|
|
// Select supports a maximum of 65536 cases.
|
|
func Select(cases []SelectCase) (chosen int, recv Value, recvOK bool) {
|
|
if len(cases) > 65536 {
|
|
panic("reflect.Select: too many cases (max 65536)")
|
|
}
|
|
// NOTE: Do not trust that caller is not modifying cases data underfoot.
|
|
// The range is safe because the caller cannot modify our copy of the len
|
|
// and each iteration makes its own copy of the value c.
|
|
var runcases []runtimeSelect
|
|
if len(cases) > 4 {
|
|
// Slice is heap allocated due to runtime dependent capacity.
|
|
runcases = make([]runtimeSelect, len(cases))
|
|
} else {
|
|
// Slice can be stack allocated due to constant capacity.
|
|
runcases = make([]runtimeSelect, len(cases), 4)
|
|
}
|
|
|
|
haveDefault := false
|
|
for i, c := range cases {
|
|
rc := &runcases[i]
|
|
rc.dir = c.Dir
|
|
switch c.Dir {
|
|
default:
|
|
panic("reflect.Select: invalid Dir")
|
|
|
|
case SelectDefault: // default
|
|
if haveDefault {
|
|
panic("reflect.Select: multiple default cases")
|
|
}
|
|
haveDefault = true
|
|
if c.Chan.IsValid() {
|
|
panic("reflect.Select: default case has Chan value")
|
|
}
|
|
if c.Send.IsValid() {
|
|
panic("reflect.Select: default case has Send value")
|
|
}
|
|
|
|
case SelectSend:
|
|
ch := c.Chan
|
|
if !ch.IsValid() {
|
|
break
|
|
}
|
|
ch.mustBe(Chan)
|
|
ch.mustBeExported()
|
|
tt := (*chanType)(unsafe.Pointer(ch.typ()))
|
|
if ChanDir(tt.Dir)&SendDir == 0 {
|
|
panic("reflect.Select: SendDir case using recv-only channel")
|
|
}
|
|
rc.ch = ch.pointer()
|
|
rc.typ = toRType(&tt.Type)
|
|
v := c.Send
|
|
if !v.IsValid() {
|
|
panic("reflect.Select: SendDir case missing Send value")
|
|
}
|
|
v.mustBeExported()
|
|
v = v.assignTo("reflect.Select", tt.Elem, nil)
|
|
if v.flag&flagIndir != 0 {
|
|
rc.val = v.ptr
|
|
} else {
|
|
rc.val = unsafe.Pointer(&v.ptr)
|
|
}
|
|
// The value to send needs to escape. See the comment at rselect for
|
|
// why we need forced escape.
|
|
escapes(rc.val)
|
|
|
|
case SelectRecv:
|
|
if c.Send.IsValid() {
|
|
panic("reflect.Select: RecvDir case has Send value")
|
|
}
|
|
ch := c.Chan
|
|
if !ch.IsValid() {
|
|
break
|
|
}
|
|
ch.mustBe(Chan)
|
|
ch.mustBeExported()
|
|
tt := (*chanType)(unsafe.Pointer(ch.typ()))
|
|
if ChanDir(tt.Dir)&RecvDir == 0 {
|
|
panic("reflect.Select: RecvDir case using send-only channel")
|
|
}
|
|
rc.ch = ch.pointer()
|
|
rc.typ = toRType(&tt.Type)
|
|
rc.val = unsafe_New(tt.Elem)
|
|
}
|
|
}
|
|
|
|
chosen, recvOK = rselect(runcases)
|
|
if runcases[chosen].dir == SelectRecv {
|
|
tt := (*chanType)(unsafe.Pointer(runcases[chosen].typ))
|
|
t := tt.Elem
|
|
p := runcases[chosen].val
|
|
fl := flag(t.Kind())
|
|
if t.IfaceIndir() {
|
|
recv = Value{t, p, fl | flagIndir}
|
|
} else {
|
|
recv = Value{t, *(*unsafe.Pointer)(p), fl}
|
|
}
|
|
}
|
|
return chosen, recv, recvOK
|
|
}
|
|
|
|
/*
|
|
* constructors
|
|
*/
|
|
|
|
// implemented in package runtime
|
|
|
|
//go:noescape
|
|
func unsafe_New(*abi.Type) unsafe.Pointer
|
|
|
|
//go:noescape
|
|
func unsafe_NewArray(*abi.Type, int) unsafe.Pointer
|
|
|
|
// MakeSlice creates a new zero-initialized slice value
|
|
// for the specified slice type, length, and capacity.
|
|
func MakeSlice(typ Type, len, cap int) Value {
|
|
if typ.Kind() != Slice {
|
|
panic("reflect.MakeSlice of non-slice type")
|
|
}
|
|
if len < 0 {
|
|
panic("reflect.MakeSlice: negative len")
|
|
}
|
|
if cap < 0 {
|
|
panic("reflect.MakeSlice: negative cap")
|
|
}
|
|
if len > cap {
|
|
panic("reflect.MakeSlice: len > cap")
|
|
}
|
|
|
|
s := unsafeheader.Slice{Data: unsafe_NewArray(&(typ.Elem().(*rtype).t), cap), Len: len, Cap: cap}
|
|
return Value{&typ.(*rtype).t, unsafe.Pointer(&s), flagIndir | flag(Slice)}
|
|
}
|
|
|
|
// SliceAt returns a [Value] representing a slice whose underlying
|
|
// data starts at p, with length and capacity equal to n.
|
|
//
|
|
// This is like [unsafe.Slice].
|
|
func SliceAt(typ Type, p unsafe.Pointer, n int) Value {
|
|
unsafeslice(typ.common(), p, n)
|
|
s := unsafeheader.Slice{Data: p, Len: n, Cap: n}
|
|
return Value{SliceOf(typ).common(), unsafe.Pointer(&s), flagIndir | flag(Slice)}
|
|
}
|
|
|
|
// MakeChan creates a new channel with the specified type and buffer size.
|
|
func MakeChan(typ Type, buffer int) Value {
|
|
if typ.Kind() != Chan {
|
|
panic("reflect.MakeChan of non-chan type")
|
|
}
|
|
if buffer < 0 {
|
|
panic("reflect.MakeChan: negative buffer size")
|
|
}
|
|
if typ.ChanDir() != BothDir {
|
|
panic("reflect.MakeChan: unidirectional channel type")
|
|
}
|
|
t := typ.common()
|
|
ch := makechan(t, buffer)
|
|
return Value{t, ch, flag(Chan)}
|
|
}
|
|
|
|
// MakeMap creates a new map with the specified type.
|
|
func MakeMap(typ Type) Value {
|
|
return MakeMapWithSize(typ, 0)
|
|
}
|
|
|
|
// MakeMapWithSize creates a new map with the specified type
|
|
// and initial space for approximately n elements.
|
|
func MakeMapWithSize(typ Type, n int) Value {
|
|
if typ.Kind() != Map {
|
|
panic("reflect.MakeMapWithSize of non-map type")
|
|
}
|
|
t := typ.common()
|
|
m := makemap(t, n)
|
|
return Value{t, m, flag(Map)}
|
|
}
|
|
|
|
// Indirect returns the value that v points to.
|
|
// If v is a nil pointer, Indirect returns a zero Value.
|
|
// If v is not a pointer, Indirect returns v.
|
|
func Indirect(v Value) Value {
|
|
if v.Kind() != Pointer {
|
|
return v
|
|
}
|
|
return v.Elem()
|
|
}
|
|
|
|
// ValueOf returns a new Value initialized to the concrete value
|
|
// stored in the interface i. ValueOf(nil) returns the zero Value.
|
|
func ValueOf(i any) Value {
|
|
if i == nil {
|
|
return Value{}
|
|
}
|
|
return unpackEface(i)
|
|
}
|
|
|
|
// Zero returns a Value representing the zero value for the specified type.
|
|
// The result is different from the zero value of the Value struct,
|
|
// which represents no value at all.
|
|
// For example, Zero(TypeOf(42)) returns a Value with Kind [Int] and value 0.
|
|
// The returned value is neither addressable nor settable.
|
|
func Zero(typ Type) Value {
|
|
if typ == nil {
|
|
panic("reflect: Zero(nil)")
|
|
}
|
|
t := &typ.(*rtype).t
|
|
fl := flag(t.Kind())
|
|
if t.IfaceIndir() {
|
|
var p unsafe.Pointer
|
|
if t.Size() <= abi.ZeroValSize {
|
|
p = unsafe.Pointer(&abi.ZeroVal[0])
|
|
} else {
|
|
p = unsafe_New(t)
|
|
}
|
|
return Value{t, p, fl | flagIndir}
|
|
}
|
|
return Value{t, nil, fl}
|
|
}
|
|
|
|
// New returns a Value representing a pointer to a new zero value
|
|
// for the specified type. That is, the returned Value's Type is [PointerTo](typ).
|
|
func New(typ Type) Value {
|
|
if typ == nil {
|
|
panic("reflect: New(nil)")
|
|
}
|
|
t := &typ.(*rtype).t
|
|
pt := ptrTo(t)
|
|
if pt.IfaceIndir() {
|
|
// This is a pointer to a not-in-heap type.
|
|
panic("reflect: New of type that may not be allocated in heap (possibly undefined cgo C type)")
|
|
}
|
|
ptr := unsafe_New(t)
|
|
fl := flag(Pointer)
|
|
return Value{pt, ptr, fl}
|
|
}
|
|
|
|
// NewAt returns a Value representing a pointer to a value of the
|
|
// specified type, using p as that pointer.
|
|
func NewAt(typ Type, p unsafe.Pointer) Value {
|
|
fl := flag(Pointer)
|
|
t := typ.(*rtype)
|
|
return Value{t.ptrTo(), p, fl}
|
|
}
|
|
|
|
// assignTo returns a value v that can be assigned directly to dst.
|
|
// It panics if v is not assignable to dst.
|
|
// For a conversion to an interface type, target, if not nil,
|
|
// is a suggested scratch space to use.
|
|
// target must be initialized memory (or nil).
|
|
func (v Value) assignTo(context string, dst *abi.Type, target unsafe.Pointer) Value {
|
|
if v.flag&flagMethod != 0 {
|
|
v = makeMethodValue(context, v)
|
|
}
|
|
|
|
switch {
|
|
case directlyAssignable(dst, v.typ()):
|
|
// Overwrite type so that they match.
|
|
// Same memory layout, so no harm done.
|
|
fl := v.flag&(flagAddr|flagIndir) | v.flag.ro()
|
|
fl |= flag(dst.Kind())
|
|
return Value{dst, v.ptr, fl}
|
|
|
|
case implements(dst, v.typ()):
|
|
if v.Kind() == Interface && v.IsNil() {
|
|
// A nil ReadWriter passed to nil Reader is OK,
|
|
// but using ifaceE2I below will panic.
|
|
// Avoid the panic by returning a nil dst (e.g., Reader) explicitly.
|
|
return Value{dst, nil, flag(Interface)}
|
|
}
|
|
x := valueInterface(v, false)
|
|
if target == nil {
|
|
target = unsafe_New(dst)
|
|
}
|
|
if dst.NumMethod() == 0 {
|
|
*(*any)(target) = x
|
|
} else {
|
|
ifaceE2I(dst, x, target)
|
|
}
|
|
return Value{dst, target, flagIndir | flag(Interface)}
|
|
}
|
|
|
|
// Failed.
|
|
panic(context + ": value of type " + stringFor(v.typ()) + " is not assignable to type " + stringFor(dst))
|
|
}
|
|
|
|
// Convert returns the value v converted to type t.
|
|
// If the usual Go conversion rules do not allow conversion
|
|
// of the value v to type t, or if converting v to type t panics, Convert panics.
|
|
func (v Value) Convert(t Type) Value {
|
|
if v.flag&flagMethod != 0 {
|
|
v = makeMethodValue("Convert", v)
|
|
}
|
|
op := convertOp(t.common(), v.typ())
|
|
if op == nil {
|
|
panic("reflect.Value.Convert: value of type " + stringFor(v.typ()) + " cannot be converted to type " + t.String())
|
|
}
|
|
return op(v, t)
|
|
}
|
|
|
|
// CanConvert reports whether the value v can be converted to type t.
|
|
// If v.CanConvert(t) returns true then v.Convert(t) will not panic.
|
|
func (v Value) CanConvert(t Type) bool {
|
|
vt := v.Type()
|
|
if !vt.ConvertibleTo(t) {
|
|
return false
|
|
}
|
|
// Converting from slice to array or to pointer-to-array can panic
|
|
// depending on the value.
|
|
switch {
|
|
case vt.Kind() == Slice && t.Kind() == Array:
|
|
if t.Len() > v.Len() {
|
|
return false
|
|
}
|
|
case vt.Kind() == Slice && t.Kind() == Pointer && t.Elem().Kind() == Array:
|
|
n := t.Elem().Len()
|
|
if n > v.Len() {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
}
|
|
|
|
// Comparable reports whether the value v is comparable.
|
|
// If the type of v is an interface, this checks the dynamic type.
|
|
// If this reports true then v.Interface() == x will not panic for any x,
|
|
// nor will v.Equal(u) for any Value u.
|
|
func (v Value) Comparable() bool {
|
|
k := v.Kind()
|
|
switch k {
|
|
case Invalid:
|
|
return false
|
|
|
|
case Array:
|
|
switch v.Type().Elem().Kind() {
|
|
case Interface, Array, Struct:
|
|
for i := 0; i < v.Type().Len(); i++ {
|
|
if !v.Index(i).Comparable() {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
}
|
|
return v.Type().Comparable()
|
|
|
|
case Interface:
|
|
return v.IsNil() || v.Elem().Comparable()
|
|
|
|
case Struct:
|
|
for i := 0; i < v.NumField(); i++ {
|
|
if !v.Field(i).Comparable() {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
|
|
default:
|
|
return v.Type().Comparable()
|
|
}
|
|
}
|
|
|
|
// Equal reports true if v is equal to u.
|
|
// For two invalid values, Equal will report true.
|
|
// For an interface value, Equal will compare the value within the interface.
|
|
// Otherwise, If the values have different types, Equal will report false.
|
|
// Otherwise, for arrays and structs Equal will compare each element in order,
|
|
// and report false if it finds non-equal elements.
|
|
// During all comparisons, if values of the same type are compared,
|
|
// and the type is not comparable, Equal will panic.
|
|
func (v Value) Equal(u Value) bool {
|
|
if v.Kind() == Interface {
|
|
v = v.Elem()
|
|
}
|
|
if u.Kind() == Interface {
|
|
u = u.Elem()
|
|
}
|
|
|
|
if !v.IsValid() || !u.IsValid() {
|
|
return v.IsValid() == u.IsValid()
|
|
}
|
|
|
|
if v.Kind() != u.Kind() || v.Type() != u.Type() {
|
|
return false
|
|
}
|
|
|
|
// Handle each Kind directly rather than calling valueInterface
|
|
// to avoid allocating.
|
|
switch v.Kind() {
|
|
default:
|
|
panic("reflect.Value.Equal: invalid Kind")
|
|
case Bool:
|
|
return v.Bool() == u.Bool()
|
|
case Int, Int8, Int16, Int32, Int64:
|
|
return v.Int() == u.Int()
|
|
case Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
|
|
return v.Uint() == u.Uint()
|
|
case Float32, Float64:
|
|
return v.Float() == u.Float()
|
|
case Complex64, Complex128:
|
|
return v.Complex() == u.Complex()
|
|
case String:
|
|
return v.String() == u.String()
|
|
case Chan, Pointer, UnsafePointer:
|
|
return v.Pointer() == u.Pointer()
|
|
case Array:
|
|
// u and v have the same type so they have the same length
|
|
vl := v.Len()
|
|
if vl == 0 {
|
|
// panic on [0]func()
|
|
if !v.Type().Elem().Comparable() {
|
|
break
|
|
}
|
|
return true
|
|
}
|
|
for i := 0; i < vl; i++ {
|
|
if !v.Index(i).Equal(u.Index(i)) {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
case Struct:
|
|
// u and v have the same type so they have the same fields
|
|
nf := v.NumField()
|
|
for i := 0; i < nf; i++ {
|
|
if !v.Field(i).Equal(u.Field(i)) {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
case Func, Map, Slice:
|
|
break
|
|
}
|
|
panic("reflect.Value.Equal: values of type " + v.Type().String() + " are not comparable")
|
|
}
|
|
|
|
// convertOp returns the function to convert a value of type src
|
|
// to a value of type dst. If the conversion is illegal, convertOp returns nil.
|
|
func convertOp(dst, src *abi.Type) func(Value, Type) Value {
|
|
switch Kind(src.Kind()) {
|
|
case Int, Int8, Int16, Int32, Int64:
|
|
switch Kind(dst.Kind()) {
|
|
case Int, Int8, Int16, Int32, Int64, Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
|
|
return cvtInt
|
|
case Float32, Float64:
|
|
return cvtIntFloat
|
|
case String:
|
|
return cvtIntString
|
|
}
|
|
|
|
case Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
|
|
switch Kind(dst.Kind()) {
|
|
case Int, Int8, Int16, Int32, Int64, Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
|
|
return cvtUint
|
|
case Float32, Float64:
|
|
return cvtUintFloat
|
|
case String:
|
|
return cvtUintString
|
|
}
|
|
|
|
case Float32, Float64:
|
|
switch Kind(dst.Kind()) {
|
|
case Int, Int8, Int16, Int32, Int64:
|
|
return cvtFloatInt
|
|
case Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
|
|
return cvtFloatUint
|
|
case Float32, Float64:
|
|
return cvtFloat
|
|
}
|
|
|
|
case Complex64, Complex128:
|
|
switch Kind(dst.Kind()) {
|
|
case Complex64, Complex128:
|
|
return cvtComplex
|
|
}
|
|
|
|
case String:
|
|
if dst.Kind() == abi.Slice && pkgPathFor(dst.Elem()) == "" {
|
|
switch Kind(dst.Elem().Kind()) {
|
|
case Uint8:
|
|
return cvtStringBytes
|
|
case Int32:
|
|
return cvtStringRunes
|
|
}
|
|
}
|
|
|
|
case Slice:
|
|
if dst.Kind() == abi.String && pkgPathFor(src.Elem()) == "" {
|
|
switch Kind(src.Elem().Kind()) {
|
|
case Uint8:
|
|
return cvtBytesString
|
|
case Int32:
|
|
return cvtRunesString
|
|
}
|
|
}
|
|
// "x is a slice, T is a pointer-to-array type,
|
|
// and the slice and array types have identical element types."
|
|
if dst.Kind() == abi.Pointer && dst.Elem().Kind() == abi.Array && src.Elem() == dst.Elem().Elem() {
|
|
return cvtSliceArrayPtr
|
|
}
|
|
// "x is a slice, T is an array type,
|
|
// and the slice and array types have identical element types."
|
|
if dst.Kind() == abi.Array && src.Elem() == dst.Elem() {
|
|
return cvtSliceArray
|
|
}
|
|
|
|
case Chan:
|
|
if dst.Kind() == abi.Chan && specialChannelAssignability(dst, src) {
|
|
return cvtDirect
|
|
}
|
|
}
|
|
|
|
// dst and src have same underlying type.
|
|
if haveIdenticalUnderlyingType(dst, src, false) {
|
|
return cvtDirect
|
|
}
|
|
|
|
// dst and src are non-defined pointer types with same underlying base type.
|
|
if dst.Kind() == abi.Pointer && nameFor(dst) == "" &&
|
|
src.Kind() == abi.Pointer && nameFor(src) == "" &&
|
|
haveIdenticalUnderlyingType(elem(dst), elem(src), false) {
|
|
return cvtDirect
|
|
}
|
|
|
|
if implements(dst, src) {
|
|
if src.Kind() == abi.Interface {
|
|
return cvtI2I
|
|
}
|
|
return cvtT2I
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// makeInt returns a Value of type t equal to bits (possibly truncated),
|
|
// where t is a signed or unsigned int type.
|
|
func makeInt(f flag, bits uint64, t Type) Value {
|
|
typ := t.common()
|
|
ptr := unsafe_New(typ)
|
|
switch typ.Size() {
|
|
case 1:
|
|
*(*uint8)(ptr) = uint8(bits)
|
|
case 2:
|
|
*(*uint16)(ptr) = uint16(bits)
|
|
case 4:
|
|
*(*uint32)(ptr) = uint32(bits)
|
|
case 8:
|
|
*(*uint64)(ptr) = bits
|
|
}
|
|
return Value{typ, ptr, f | flagIndir | flag(typ.Kind())}
|
|
}
|
|
|
|
// makeFloat returns a Value of type t equal to v (possibly truncated to float32),
|
|
// where t is a float32 or float64 type.
|
|
func makeFloat(f flag, v float64, t Type) Value {
|
|
typ := t.common()
|
|
ptr := unsafe_New(typ)
|
|
switch typ.Size() {
|
|
case 4:
|
|
*(*float32)(ptr) = float32(v)
|
|
case 8:
|
|
*(*float64)(ptr) = v
|
|
}
|
|
return Value{typ, ptr, f | flagIndir | flag(typ.Kind())}
|
|
}
|
|
|
|
// makeFloat32 returns a Value of type t equal to v, where t is a float32 type.
|
|
func makeFloat32(f flag, v float32, t Type) Value {
|
|
typ := t.common()
|
|
ptr := unsafe_New(typ)
|
|
*(*float32)(ptr) = v
|
|
return Value{typ, ptr, f | flagIndir | flag(typ.Kind())}
|
|
}
|
|
|
|
// makeComplex returns a Value of type t equal to v (possibly truncated to complex64),
|
|
// where t is a complex64 or complex128 type.
|
|
func makeComplex(f flag, v complex128, t Type) Value {
|
|
typ := t.common()
|
|
ptr := unsafe_New(typ)
|
|
switch typ.Size() {
|
|
case 8:
|
|
*(*complex64)(ptr) = complex64(v)
|
|
case 16:
|
|
*(*complex128)(ptr) = v
|
|
}
|
|
return Value{typ, ptr, f | flagIndir | flag(typ.Kind())}
|
|
}
|
|
|
|
func makeString(f flag, v string, t Type) Value {
|
|
ret := New(t).Elem()
|
|
ret.SetString(v)
|
|
ret.flag = ret.flag&^flagAddr | f
|
|
return ret
|
|
}
|
|
|
|
func makeBytes(f flag, v []byte, t Type) Value {
|
|
ret := New(t).Elem()
|
|
ret.SetBytes(v)
|
|
ret.flag = ret.flag&^flagAddr | f
|
|
return ret
|
|
}
|
|
|
|
func makeRunes(f flag, v []rune, t Type) Value {
|
|
ret := New(t).Elem()
|
|
ret.setRunes(v)
|
|
ret.flag = ret.flag&^flagAddr | f
|
|
return ret
|
|
}
|
|
|
|
// These conversion functions are returned by convertOp
|
|
// for classes of conversions. For example, the first function, cvtInt,
|
|
// takes any value v of signed int type and returns the value converted
|
|
// to type t, where t is any signed or unsigned int type.
|
|
|
|
// convertOp: intXX -> [u]intXX
|
|
func cvtInt(v Value, t Type) Value {
|
|
return makeInt(v.flag.ro(), uint64(v.Int()), t)
|
|
}
|
|
|
|
// convertOp: uintXX -> [u]intXX
|
|
func cvtUint(v Value, t Type) Value {
|
|
return makeInt(v.flag.ro(), v.Uint(), t)
|
|
}
|
|
|
|
// convertOp: floatXX -> intXX
|
|
func cvtFloatInt(v Value, t Type) Value {
|
|
return makeInt(v.flag.ro(), uint64(int64(v.Float())), t)
|
|
}
|
|
|
|
// convertOp: floatXX -> uintXX
|
|
func cvtFloatUint(v Value, t Type) Value {
|
|
return makeInt(v.flag.ro(), uint64(v.Float()), t)
|
|
}
|
|
|
|
// convertOp: intXX -> floatXX
|
|
func cvtIntFloat(v Value, t Type) Value {
|
|
return makeFloat(v.flag.ro(), float64(v.Int()), t)
|
|
}
|
|
|
|
// convertOp: uintXX -> floatXX
|
|
func cvtUintFloat(v Value, t Type) Value {
|
|
return makeFloat(v.flag.ro(), float64(v.Uint()), t)
|
|
}
|
|
|
|
// convertOp: floatXX -> floatXX
|
|
func cvtFloat(v Value, t Type) Value {
|
|
if v.Type().Kind() == Float32 && t.Kind() == Float32 {
|
|
// Don't do any conversion if both types have underlying type float32.
|
|
// This avoids converting to float64 and back, which will
|
|
// convert a signaling NaN to a quiet NaN. See issue 36400.
|
|
return makeFloat32(v.flag.ro(), *(*float32)(v.ptr), t)
|
|
}
|
|
return makeFloat(v.flag.ro(), v.Float(), t)
|
|
}
|
|
|
|
// convertOp: complexXX -> complexXX
|
|
func cvtComplex(v Value, t Type) Value {
|
|
return makeComplex(v.flag.ro(), v.Complex(), t)
|
|
}
|
|
|
|
// convertOp: intXX -> string
|
|
func cvtIntString(v Value, t Type) Value {
|
|
s := "\uFFFD"
|
|
if x := v.Int(); int64(rune(x)) == x {
|
|
s = string(rune(x))
|
|
}
|
|
return makeString(v.flag.ro(), s, t)
|
|
}
|
|
|
|
// convertOp: uintXX -> string
|
|
func cvtUintString(v Value, t Type) Value {
|
|
s := "\uFFFD"
|
|
if x := v.Uint(); uint64(rune(x)) == x {
|
|
s = string(rune(x))
|
|
}
|
|
return makeString(v.flag.ro(), s, t)
|
|
}
|
|
|
|
// convertOp: []byte -> string
|
|
func cvtBytesString(v Value, t Type) Value {
|
|
return makeString(v.flag.ro(), string(v.Bytes()), t)
|
|
}
|
|
|
|
// convertOp: string -> []byte
|
|
func cvtStringBytes(v Value, t Type) Value {
|
|
return makeBytes(v.flag.ro(), []byte(v.String()), t)
|
|
}
|
|
|
|
// convertOp: []rune -> string
|
|
func cvtRunesString(v Value, t Type) Value {
|
|
return makeString(v.flag.ro(), string(v.runes()), t)
|
|
}
|
|
|
|
// convertOp: string -> []rune
|
|
func cvtStringRunes(v Value, t Type) Value {
|
|
return makeRunes(v.flag.ro(), []rune(v.String()), t)
|
|
}
|
|
|
|
// convertOp: []T -> *[N]T
|
|
func cvtSliceArrayPtr(v Value, t Type) Value {
|
|
n := t.Elem().Len()
|
|
if n > v.Len() {
|
|
panic("reflect: cannot convert slice with length " + itoa.Itoa(v.Len()) + " to pointer to array with length " + itoa.Itoa(n))
|
|
}
|
|
h := (*unsafeheader.Slice)(v.ptr)
|
|
return Value{t.common(), h.Data, v.flag&^(flagIndir|flagAddr|flagKindMask) | flag(Pointer)}
|
|
}
|
|
|
|
// convertOp: []T -> [N]T
|
|
func cvtSliceArray(v Value, t Type) Value {
|
|
n := t.Len()
|
|
if n > v.Len() {
|
|
panic("reflect: cannot convert slice with length " + itoa.Itoa(v.Len()) + " to array with length " + itoa.Itoa(n))
|
|
}
|
|
h := (*unsafeheader.Slice)(v.ptr)
|
|
typ := t.common()
|
|
ptr := h.Data
|
|
c := unsafe_New(typ)
|
|
typedmemmove(typ, c, ptr)
|
|
ptr = c
|
|
|
|
return Value{typ, ptr, v.flag&^(flagAddr|flagKindMask) | flag(Array)}
|
|
}
|
|
|
|
// convertOp: direct copy
|
|
func cvtDirect(v Value, typ Type) Value {
|
|
f := v.flag
|
|
t := typ.common()
|
|
ptr := v.ptr
|
|
if f&flagAddr != 0 {
|
|
// indirect, mutable word - make a copy
|
|
c := unsafe_New(t)
|
|
typedmemmove(t, c, ptr)
|
|
ptr = c
|
|
f &^= flagAddr
|
|
}
|
|
return Value{t, ptr, v.flag.ro() | f} // v.flag.ro()|f == f?
|
|
}
|
|
|
|
// convertOp: concrete -> interface
|
|
func cvtT2I(v Value, typ Type) Value {
|
|
target := unsafe_New(typ.common())
|
|
x := valueInterface(v, false)
|
|
if typ.NumMethod() == 0 {
|
|
*(*any)(target) = x
|
|
} else {
|
|
ifaceE2I(typ.common(), x, target)
|
|
}
|
|
return Value{typ.common(), target, v.flag.ro() | flagIndir | flag(Interface)}
|
|
}
|
|
|
|
// convertOp: interface -> interface
|
|
func cvtI2I(v Value, typ Type) Value {
|
|
if v.IsNil() {
|
|
ret := Zero(typ)
|
|
ret.flag |= v.flag.ro()
|
|
return ret
|
|
}
|
|
return cvtT2I(v.Elem(), typ)
|
|
}
|
|
|
|
// implemented in ../runtime
|
|
//
|
|
//go:noescape
|
|
func chancap(ch unsafe.Pointer) int
|
|
|
|
//go:noescape
|
|
func chanclose(ch unsafe.Pointer)
|
|
|
|
//go:noescape
|
|
func chanlen(ch unsafe.Pointer) int
|
|
|
|
// Note: some of the noescape annotations below are technically a lie,
|
|
// but safe in the context of this package. Functions like chansend0
|
|
// and mapassign0 don't escape the referent, but may escape anything
|
|
// the referent points to (they do shallow copies of the referent).
|
|
// We add a 0 to their names and wrap them in functions with the
|
|
// proper escape behavior.
|
|
|
|
//go:noescape
|
|
func chanrecv(ch unsafe.Pointer, nb bool, val unsafe.Pointer) (selected, received bool)
|
|
|
|
//go:noescape
|
|
func chansend0(ch unsafe.Pointer, val unsafe.Pointer, nb bool) bool
|
|
|
|
func chansend(ch unsafe.Pointer, val unsafe.Pointer, nb bool) bool {
|
|
contentEscapes(val)
|
|
return chansend0(ch, val, nb)
|
|
}
|
|
|
|
func makechan(typ *abi.Type, size int) (ch unsafe.Pointer)
|
|
func makemap(t *abi.Type, cap int) (m unsafe.Pointer)
|
|
|
|
//go:noescape
|
|
func mapaccess(t *abi.Type, m unsafe.Pointer, key unsafe.Pointer) (val unsafe.Pointer)
|
|
|
|
//go:noescape
|
|
func mapaccess_faststr(t *abi.Type, m unsafe.Pointer, key string) (val unsafe.Pointer)
|
|
|
|
//go:noescape
|
|
func mapassign0(t *abi.Type, m unsafe.Pointer, key, val unsafe.Pointer)
|
|
|
|
func mapassign(t *abi.Type, m unsafe.Pointer, key, val unsafe.Pointer) {
|
|
contentEscapes(key)
|
|
contentEscapes(val)
|
|
mapassign0(t, m, key, val)
|
|
}
|
|
|
|
//go:noescape
|
|
func mapassign_faststr0(t *abi.Type, m unsafe.Pointer, key string, val unsafe.Pointer)
|
|
|
|
func mapassign_faststr(t *abi.Type, m unsafe.Pointer, key string, val unsafe.Pointer) {
|
|
contentEscapes((*unsafeheader.String)(unsafe.Pointer(&key)).Data)
|
|
contentEscapes(val)
|
|
mapassign_faststr0(t, m, key, val)
|
|
}
|
|
|
|
//go:noescape
|
|
func mapdelete(t *abi.Type, m unsafe.Pointer, key unsafe.Pointer)
|
|
|
|
//go:noescape
|
|
func mapdelete_faststr(t *abi.Type, m unsafe.Pointer, key string)
|
|
|
|
//go:noescape
|
|
func mapiterinit(t *abi.Type, m unsafe.Pointer, it *hiter)
|
|
|
|
//go:noescape
|
|
func mapiterkey(it *hiter) (key unsafe.Pointer)
|
|
|
|
//go:noescape
|
|
func mapiterelem(it *hiter) (elem unsafe.Pointer)
|
|
|
|
//go:noescape
|
|
func mapiternext(it *hiter)
|
|
|
|
//go:noescape
|
|
func maplen(m unsafe.Pointer) int
|
|
|
|
func mapclear(t *abi.Type, m unsafe.Pointer)
|
|
|
|
// call calls fn with "stackArgsSize" bytes of stack arguments laid out
|
|
// at stackArgs and register arguments laid out in regArgs. frameSize is
|
|
// the total amount of stack space that will be reserved by call, so this
|
|
// should include enough space to spill register arguments to the stack in
|
|
// case of preemption.
|
|
//
|
|
// After fn returns, call copies stackArgsSize-stackRetOffset result bytes
|
|
// back into stackArgs+stackRetOffset before returning, for any return
|
|
// values passed on the stack. Register-based return values will be found
|
|
// in the same regArgs structure.
|
|
//
|
|
// regArgs must also be prepared with an appropriate ReturnIsPtr bitmap
|
|
// indicating which registers will contain pointer-valued return values. The
|
|
// purpose of this bitmap is to keep pointers visible to the GC between
|
|
// returning from reflectcall and actually using them.
|
|
//
|
|
// If copying result bytes back from the stack, the caller must pass the
|
|
// argument frame type as stackArgsType, so that call can execute appropriate
|
|
// write barriers during the copy.
|
|
//
|
|
// Arguments passed through to call do not escape. The type is used only in a
|
|
// very limited callee of call, the stackArgs are copied, and regArgs is only
|
|
// used in the call frame.
|
|
//
|
|
//go:noescape
|
|
//go:linkname call runtime.reflectcall
|
|
func call(stackArgsType *abi.Type, f, stackArgs unsafe.Pointer, stackArgsSize, stackRetOffset, frameSize uint32, regArgs *abi.RegArgs)
|
|
|
|
func ifaceE2I(t *abi.Type, src any, dst unsafe.Pointer)
|
|
|
|
// memmove copies size bytes to dst from src. No write barriers are used.
|
|
//
|
|
//go:noescape
|
|
func memmove(dst, src unsafe.Pointer, size uintptr)
|
|
|
|
// typedmemmove copies a value of type t to dst from src.
|
|
//
|
|
//go:noescape
|
|
func typedmemmove(t *abi.Type, dst, src unsafe.Pointer)
|
|
|
|
// typedmemclr zeros the value at ptr of type t.
|
|
//
|
|
//go:noescape
|
|
func typedmemclr(t *abi.Type, ptr unsafe.Pointer)
|
|
|
|
// typedmemclrpartial is like typedmemclr but assumes that
|
|
// dst points off bytes into the value and only clears size bytes.
|
|
//
|
|
//go:noescape
|
|
func typedmemclrpartial(t *abi.Type, ptr unsafe.Pointer, off, size uintptr)
|
|
|
|
// typedslicecopy copies a slice of elemType values from src to dst,
|
|
// returning the number of elements copied.
|
|
//
|
|
//go:noescape
|
|
func typedslicecopy(t *abi.Type, dst, src unsafeheader.Slice) int
|
|
|
|
// typedarrayclear zeroes the value at ptr of an array of elemType,
|
|
// only clears len elem.
|
|
//
|
|
//go:noescape
|
|
func typedarrayclear(elemType *abi.Type, ptr unsafe.Pointer, len int)
|
|
|
|
//go:noescape
|
|
func typehash(t *abi.Type, p unsafe.Pointer, h uintptr) uintptr
|
|
|
|
func verifyNotInHeapPtr(p uintptr) bool
|
|
|
|
//go:noescape
|
|
func growslice(t *abi.Type, old unsafeheader.Slice, num int) unsafeheader.Slice
|
|
|
|
//go:noescape
|
|
func unsafeslice(t *abi.Type, ptr unsafe.Pointer, len int)
|
|
|
|
// Dummy annotation marking that the value x escapes,
|
|
// for use in cases where the reflect code is so clever that
|
|
// the compiler cannot follow.
|
|
func escapes(x any) {
|
|
if dummy.b {
|
|
dummy.x = x
|
|
}
|
|
}
|
|
|
|
var dummy struct {
|
|
b bool
|
|
x any
|
|
}
|
|
|
|
// Dummy annotation marking that the content of value x
|
|
// escapes (i.e. modeling roughly heap=*x),
|
|
// for use in cases where the reflect code is so clever that
|
|
// the compiler cannot follow.
|
|
func contentEscapes(x unsafe.Pointer) {
|
|
if dummy.b {
|
|
escapes(*(*any)(x)) // the dereference may not always be safe, but never executed
|
|
}
|
|
}
|
|
|
|
// This is just a wrapper around abi.NoEscape. The inlining heuristics are
|
|
// finnicky and for whatever reason treat the local call to noescape as much
|
|
// lower cost with respect to the inliner budget. (That is, replacing calls to
|
|
// noescape with abi.NoEscape will cause inlining tests to fail.)
|
|
//
|
|
//go:nosplit
|
|
func noescape(p unsafe.Pointer) unsafe.Pointer {
|
|
return abi.NoEscape(p)
|
|
}
|