mirror of https://github.com/gohugoio/hugo
81 lines
1.8 KiB
Go
81 lines
1.8 KiB
Go
// Copyright 2024 The Hugo Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package collections
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import "sync"
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// Stack is a simple LIFO stack that is safe for concurrent use.
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type Stack[T any] struct {
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items []T
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zero T
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mu sync.RWMutex
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}
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func NewStack[T any]() *Stack[T] {
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return &Stack[T]{}
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}
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func (s *Stack[T]) Push(item T) {
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s.mu.Lock()
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defer s.mu.Unlock()
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s.items = append(s.items, item)
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}
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func (s *Stack[T]) Pop() (T, bool) {
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s.mu.Lock()
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defer s.mu.Unlock()
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if len(s.items) == 0 {
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return s.zero, false
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}
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item := s.items[len(s.items)-1]
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s.items = s.items[:len(s.items)-1]
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return item, true
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}
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func (s *Stack[T]) Peek() (T, bool) {
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s.mu.RLock()
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defer s.mu.RUnlock()
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if len(s.items) == 0 {
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return s.zero, false
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}
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return s.items[len(s.items)-1], true
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}
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func (s *Stack[T]) Len() int {
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s.mu.RLock()
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defer s.mu.RUnlock()
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return len(s.items)
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}
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func (s *Stack[T]) Drain() []T {
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s.mu.Lock()
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defer s.mu.Unlock()
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items := s.items
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s.items = nil
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return items
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}
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func (s *Stack[T]) DrainMatching(predicate func(T) bool) []T {
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s.mu.Lock()
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defer s.mu.Unlock()
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var items []T
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for i := len(s.items) - 1; i >= 0; i-- {
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if predicate(s.items[i]) {
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items = append(items, s.items[i])
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s.items = append(s.items[:i], s.items[i+1:]...)
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}
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}
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return items
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}
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