119 lines
1.8 KiB
Go
119 lines
1.8 KiB
Go
package context
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import "sync"
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type AttributeManager interface {
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Attributes() Attributes
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}
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type Attributes interface {
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initialize()
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Set(key string, value interface{})
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Get(key string) (value interface{})
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Remove(key string)
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Contains(key string) (exist bool)
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Destroy()
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}
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func NewAttributes(parent Attributes) Attributes {
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am := &attributes{
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Parent: parent,
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}
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am.initialize()
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return am
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}
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type attributes struct {
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Parent Attributes
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values map[string]interface{}
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mtx sync.RWMutex
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}
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func (am *attributes) initialize() {
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if nil != am.Parent {
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am.Parent.initialize()
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}
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if nil == am.values {
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am.Destroy()
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}
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am.values = make(map[string]interface{})
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}
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func (am *attributes) Set(key string, value interface{}) {
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am.checkInitialized()
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am.mtx.Lock()
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defer am.mtx.Unlock()
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am.values[key] = value
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}
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func (am *attributes) Get(key string) (value interface{}) {
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am.checkInitialized()
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am.mtx.RLock()
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defer am.mtx.RUnlock()
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if _, ok := am.values[key]; ok {
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return am.values[key]
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}
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if nil == am.Parent {
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return nil
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}
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return am.Parent.Get(key)
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}
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func (am *attributes) Remove(key string) {
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am.checkInitialized()
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am.mtx.Lock()
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defer am.mtx.Unlock()
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if _, ok := am.values[key]; ok {
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delete(am.values, key)
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return
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}
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if nil == am.Parent {
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return
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}
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am.Parent.Remove(key)
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}
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func (am *attributes) Contains(key string) (exist bool) {
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am.checkInitialized()
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am.mtx.RLock()
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defer am.mtx.RUnlock()
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if _, ok := am.values[key]; ok {
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return true
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}
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if nil == am.Parent {
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return false
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}
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return am.Parent.Contains(key)
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}
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func (am *attributes) Destroy() {
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if nil != am.values {
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am.values = nil
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}
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if nil != am.Parent {
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am.Parent.Destroy()
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}
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}
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func (am *attributes) checkInitialized() {
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if nil == am.values {
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panic("Attribute Manager: must be initialized")
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}
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}
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