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hugo/common/hugio/readers.go

107 lines
3.0 KiB
Go

// Copyright 2019 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package hugio
import (
"bytes"
"io"
"strings"
)
// ReadSeeker wraps io.Reader and io.Seeker.
type ReadSeeker interface {
io.Reader
io.Seeker
}
// ReadSeekCloser is implemented by afero.File. We use this as the common type for
// content in Resource objects, even for strings.
type ReadSeekCloser interface {
ReadSeeker
io.Closer
}
// ReadSeekCloserProvider provides a ReadSeekCloser.
type ReadSeekCloserProvider interface {
ReadSeekCloser() (ReadSeekCloser, error)
}
// readSeekerNopCloser implements ReadSeekCloser by doing nothing in Close.
type readSeekerNopCloser struct {
ReadSeeker
}
// Close does nothing.
func (r readSeekerNopCloser) Close() error {
return nil
}
// NewReadSeekerNoOpCloser creates a new ReadSeekerNoOpCloser with the given ReadSeeker.
func NewReadSeekerNoOpCloser(r ReadSeeker) ReadSeekCloser {
return readSeekerNopCloser{r}
}
// NewReadSeekerNoOpCloserFromString uses strings.NewReader to create a new ReadSeekerNoOpCloser
// from the given string.
func NewReadSeekerNoOpCloserFromString(content string) ReadSeekCloser {
return stringReadSeeker{s: content, readSeekerNopCloser: readSeekerNopCloser{strings.NewReader(content)}}
}
var _ StringReader = (*stringReadSeeker)(nil)
type stringReadSeeker struct {
s string
readSeekerNopCloser
}
func (s *stringReadSeeker) ReadString() string {
return s.s
}
// StringReader provides a way to read a string.
type StringReader interface {
ReadString() string
}
// NewReadSeekerNoOpCloserFromString uses strings.NewReader to create a new ReadSeekerNoOpCloser
// from the given bytes slice.
func NewReadSeekerNoOpCloserFromBytes(content []byte) readSeekerNopCloser {
return readSeekerNopCloser{bytes.NewReader(content)}
}
// NewReadSeekCloser creates a new ReadSeekCloser from the given ReadSeeker.
// The ReadSeeker will be seeked to the beginning before returned.
func NewOpenReadSeekCloser(r ReadSeekCloser) OpenReadSeekCloser {
return func() (ReadSeekCloser, error) {
r.Seek(0, io.SeekStart)
return r, nil
}
}
// OpenReadSeekCloser allows setting some other way (than reading from a filesystem)
// to open or create a ReadSeekCloser.
type OpenReadSeekCloser func() (ReadSeekCloser, error)
// ReadString reads from the given reader and returns the content as a string.
func ReadString(r io.Reader) (string, error) {
if sr, ok := r.(StringReader); ok {
return sr.ReadString(), nil
}
b, err := io.ReadAll(r)
if err != nil {
return "", err
}
return string(b), nil
}