Files
dolt/go/libraries/utils/concurrentmap/concurrentmap.go
Alex Giurgiu 9358062a67 method docs
2023-11-13 21:42:28 +02:00

103 lines
2.6 KiB
Go

// Copyright 2021 Dolthub, Inc.
//
// 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 concurrentmap
import (
"encoding/json"
"sync"
)
func New[K comparable, V any]() *Map[K, V] {
return &Map[K, V]{m: make(map[K]V)}
}
type Map[K comparable, V any] struct {
mu sync.RWMutex
m map[K]V
}
// Get returns the value for the given key. If the key does not exist, the zero value for the value type will be returned.
func (cm *Map[K, V]) Get(key K) (V, bool) {
cm.mu.RLock()
defer cm.mu.RUnlock()
if value, found := cm.m[key]; found {
return value, true
}
var zero V
return zero, false
}
// Set sets the value for the given key. If the key already exists, it will be overwritten.
func (cm *Map[K, V]) Set(key K, value V) {
cm.mu.Lock()
defer cm.mu.Unlock()
cm.m[key] = value
}
// Delete removes the key from the map if it exists. If the key does not exist, this is a no-op.
func (cm *Map[K, V]) Delete(key K) {
cm.mu.Lock()
defer cm.mu.Unlock()
delete(cm.m, key)
}
// Len returns the number of items in the map at the time of the call.
func (cm *Map[K, V]) Len() int {
cm.mu.RLock()
defer cm.mu.RUnlock()
return len(cm.m)
}
// DeepCopy returns a deep copy of the concurrent map.
func (cm *Map[K, V]) DeepCopy() *Map[K, V] {
cm.mu.RLock()
defer cm.mu.RUnlock()
newMap := make(map[K]V, len(cm.m))
for k, v := range cm.m {
newMap[k] = v
}
return &Map[K, V]{m: newMap}
}
// Iter iterates over the map, calling the provided function for each key/value pair. If the function returns false, the iteration stops.
func (cm *Map[K, V]) Iter(f func(key K, value V) bool) {
cm.mu.RLock()
defer cm.mu.RUnlock()
for k, v := range cm.m {
if !f(k, v) {
break
}
}
}
// Snapshot returns a copy of the internal map at the time of the call. Returns a native map, not a concurrent one.
func (cm *Map[K, V]) Snapshot() map[K]V {
cm.mu.RLock()
defer cm.mu.RUnlock()
newMap := make(map[K]V, len(cm.m))
for k, v := range cm.m {
newMap[k] = v
}
return newMap
}
func (cm *Map[K, V]) MarshalJSON() ([]byte, error) {
return json.Marshal(cm.Snapshot())
}
func (cm *Map[K, V]) UnmarshalJSON(data []byte) error {
return json.Unmarshal(data, &cm.m)
}