103 lines
1.7 KiB
Go
103 lines
1.7 KiB
Go
package context
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import "sync"
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type ContextKey string
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func (c ContextKey) String() string {
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return string(c)
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}
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func NewContext(parent Context) Context {
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c := &defaultContext{
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Context: parent,
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}
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c.attributes = make(map[string]interface{})
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return c
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}
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type Context interface {
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Parent() Context
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SetAttribute(key string, value interface{})
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GetAttribute(key string) (value interface{})
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RemoveAttribute(key string)
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ContainsAttribute(key string) (exist bool)
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}
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type defaultContext struct {
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Context
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attributes map[string]interface{}
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mtx sync.RWMutex
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}
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func (dc *defaultContext) Parent() Context {
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return dc.Context
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}
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func (dc *defaultContext) SetAttribute(key string, value interface{}) {
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dc.checkInitialized()
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dc.mtx.Lock()
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defer dc.mtx.Unlock()
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dc.attributes[key] = value
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}
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func (dc *defaultContext) GetAttribute(key string) (value interface{}) {
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dc.checkInitialized()
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dc.mtx.RLock()
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defer dc.mtx.RUnlock()
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if _, ok := dc.attributes[key]; ok {
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return dc.attributes[key]
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}
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if nil == dc.Context {
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return nil
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}
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return dc.Context.GetAttribute(key)
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}
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func (dc *defaultContext) RemoveAttribute(key string) {
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dc.checkInitialized()
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dc.mtx.Lock()
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defer dc.mtx.Unlock()
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if _, ok := dc.attributes[key]; ok {
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delete(dc.attributes, key)
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return
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}
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if nil == dc.Context {
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return
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}
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dc.Context.RemoveAttribute(key)
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}
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func (dc *defaultContext) ContainsAttribute(key string) (exist bool) {
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dc.checkInitialized()
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dc.mtx.RLock()
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defer dc.mtx.RUnlock()
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if _, ok := dc.attributes[key]; ok {
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return true
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}
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if nil == dc.Context {
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return false
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}
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return dc.Context.ContainsAttribute(key)
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}
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func (dc *defaultContext) checkInitialized() {
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if nil == dc.attributes {
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panic("Attribute Manager: must be initialized")
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}
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}
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