mirror of
https://github.com/gohugoio/hugo.git
synced 2026-08-24 15:28:54 +00:00
Bjørn Erik Pedersen
608ed09a0a
Go's stdlid now has a maps package, which is very useful. We have been using imports on the form `xmaps "maps"`, but auto import tools doesn't handle this, which is annoying. I have been thinking about this for some time, but have been holding back because of all the import changes. However, now is a good time to do this, with very little unmerged code.
130 lines
3.0 KiB
Go
130 lines
3.0 KiB
Go
// Copyright 2026 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 hmaps
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import (
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"iter"
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"sync"
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)
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func NewMap[K comparable, T any]() *Map[K, T] {
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return &Map[K, T]{
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m: make(map[K]T),
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}
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}
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// Map is a thread safe map backed by a Go map.
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type Map[K comparable, T any] struct {
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m map[K]T
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mu sync.RWMutex
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}
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// Get gets the value for the given key.
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// It returns the zero value of T if the key is not found.
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func (m *Map[K, T]) Get(key K) T {
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v, _ := m.Lookup(key)
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return v
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}
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// Lookup looks up the given key in the map.
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// It returns the value and a boolean indicating whether the key was found.
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func (m *Map[K, T]) Lookup(key K) (T, bool) {
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m.mu.RLock()
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v, found := m.m[key]
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m.mu.RUnlock()
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return v, found
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}
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// GetOrCreate gets the value for the given key if it exists, or creates it if not.
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func (m *Map[K, T]) GetOrCreate(key K, create func() (T, error)) (T, error) {
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v, found := m.Lookup(key)
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if found {
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return v, nil
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}
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m.mu.Lock()
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defer m.mu.Unlock()
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v, found = m.m[key]
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if found {
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return v, nil
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}
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v, err := create()
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if err != nil {
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return v, err
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}
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m.m[key] = v
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return v, nil
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}
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// Set sets the given key to the given value.
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func (m *Map[K, T]) Set(key K, value T) {
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m.mu.Lock()
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m.m[key] = value
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m.mu.Unlock()
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}
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// Delete deletes the given key from the map.
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// It returns true if the key was found and deleted, false otherwise.
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func (m *Map[K, T]) Delete(key K) bool {
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m.mu.Lock()
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defer m.mu.Unlock()
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if _, found := m.m[key]; found {
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delete(m.m, key)
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return true
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}
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return false
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}
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// WithWriteLock executes the given function with a write lock on the map.
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func (m *Map[K, T]) WithWriteLock(f func(m map[K]T) error) error {
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m.mu.Lock()
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defer m.mu.Unlock()
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return f(m.m)
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}
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// SetIfAbsent sets the given key to the given value if the key does not already exist in the map.
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// It returns true if the value was set, false otherwise.
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func (m *Map[K, T]) SetIfAbsent(key K, value T) bool {
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m.mu.RLock()
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if _, found := m.m[key]; !found {
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m.mu.RUnlock()
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return m.doSetIfAbsent(key, value)
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}
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m.mu.RUnlock()
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return false
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}
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func (m *Map[K, T]) doSetIfAbsent(key K, value T) bool {
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m.mu.Lock()
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defer m.mu.Unlock()
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if _, found := m.m[key]; !found {
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m.m[key] = value
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return true
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}
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return false
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}
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// All returns an iterator over all key/value pairs in the map.
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// A read lock is held during the iteration.
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func (m *Map[K, T]) All() iter.Seq2[K, T] {
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return func(yield func(K, T) bool) {
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m.mu.RLock()
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defer m.mu.RUnlock()
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for k, v := range m.m {
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if !yield(k, v) {
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return
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}
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}
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}
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}
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