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39 lines
846 B
39 lines
846 B
package util
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import (
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"sync"
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)
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// A mostly for read map, which can thread-safely
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// initialize the map entries.
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type ConcurrentReadMap struct {
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rmutex sync.RWMutex
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mutex sync.Mutex
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Items map[string]interface{}
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}
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func NewConcurrentReadMap() *ConcurrentReadMap {
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return &ConcurrentReadMap{Items: make(map[string]interface{})}
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}
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func (m *ConcurrentReadMap) initMapEntry(key string, newEntry func() interface{}) (value interface{}) {
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m.mutex.Lock()
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defer m.mutex.Unlock()
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if value, ok := m.Items[key]; ok {
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return value
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}
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value = newEntry()
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m.Items[key] = value
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return value
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}
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func (m *ConcurrentReadMap) Get(key string, newEntry func() interface{}) interface{} {
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m.rmutex.RLock()
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if value, ok := m.Items[key]; ok {
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m.rmutex.RUnlock()
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return value
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} else {
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m.rmutex.RUnlock()
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return m.initMapEntry(key, newEntry)
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}
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}
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