95 lines
2.6 KiB
Go
95 lines
2.6 KiB
Go
// Copyright (c) 2023 Tulir Asokan
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at http://mozilla.org/MPL/2.0/.
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package util
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import "sync"
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// SyncMap is a simple map with a built-in mutex.
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type SyncMap[Key comparable, Value any] struct {
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data map[Key]Value
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lock sync.RWMutex
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}
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func NewSyncMap[Key comparable, Value any]() *SyncMap[Key, Value] {
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return &SyncMap[Key, Value]{
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data: make(map[Key]Value),
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}
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}
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// Set stores a value in the map.
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func (sm *SyncMap[Key, Value]) Set(key Key, value Value) {
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sm.Swap(key, value)
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}
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// Swap sets a value in the map and returns the old value.
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//
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// The boolean return parameter is true if the value already existed, false if not.
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func (sm *SyncMap[Key, Value]) Swap(key Key, value Value) (oldValue Value, wasReplaced bool) {
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sm.lock.Lock()
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oldValue, wasReplaced = sm.data[key]
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sm.data[key] = value
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sm.lock.Unlock()
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return
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}
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// Delete removes a key from the map.
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func (sm *SyncMap[Key, Value]) Delete(key Key) {
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sm.Pop(key)
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}
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// Pop removes a key from the map and returns the old value.
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//
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// The boolean return parameter is the same as with normal Go map access (true if the key exists, false if not).
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func (sm *SyncMap[Key, Value]) Pop(key Key) (value Value, ok bool) {
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sm.lock.Lock()
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value, ok = sm.data[key]
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delete(sm.data, key)
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sm.lock.Unlock()
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return
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}
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// Get gets a value in the map.
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//
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// The boolean return parameter is the same as with normal Go map access (true if the key exists, false if not).
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func (sm *SyncMap[Key, Value]) Get(key Key) (value Value, ok bool) {
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sm.lock.RLock()
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value, ok = sm.data[key]
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sm.lock.RUnlock()
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return
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}
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// GetOrSet gets a value in the map if the key already exists, otherwise inserts the given value and returns it.
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//
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// The boolean return parameter is true if the key already exists, and false if the given value was inserted.
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func (sm *SyncMap[Key, Value]) GetOrSet(key Key, value Value) (actual Value, wasGet bool) {
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sm.lock.Lock()
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defer sm.lock.Unlock()
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actual, wasGet = sm.data[key]
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if wasGet {
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return
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}
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sm.data[key] = value
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actual = value
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return
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}
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// Clone returns a copy of the map.
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func (sm *SyncMap[Key, Value]) Clone() *SyncMap[Key, Value] {
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return &SyncMap[Key, Value]{data: sm.CopyData()}
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}
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// CopyData returns a copy of the data in the map as a normal (non-atomic) map.
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func (sm *SyncMap[Key, Value]) CopyData() map[Key]Value {
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sm.lock.RLock()
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copied := make(map[Key]Value, len(sm.data))
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for key, value := range sm.data {
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copied[key] = value
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}
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sm.lock.RUnlock()
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return copied
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}
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