106 行
2.4 KiB
Go
106 行
2.4 KiB
Go
package extension
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import (
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"fmt"
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"sync"
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)
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// The global mapping of names to specific vocabularies and the plugins
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// providing their implementations.
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var (
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pluginRegistry = make(map[string]Plugin)
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pluginRegistryMu sync.RWMutex
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)
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func RegisteredPlugins() []string {
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pluginRegistryMu.RLock()
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defer pluginRegistryMu.RUnlock()
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s := make([]string, 0, len(pluginRegistry))
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for name, _ := range pluginRegistry {
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s = append(s, name)
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}
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return s
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}
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/* BEGIN TEST SPECIFIC STUFF */
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func unregisterAllExtensions() {
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pluginRegistryMu.Lock()
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defer pluginRegistryMu.Unlock()
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pluginRegistry = make(map[string]Plugin)
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}
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/* BEGIN STATIC SPECIFIC STUFF */
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func RegisterExtension(name string, plugin Plugin) {
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pluginRegistryMu.Lock()
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defer pluginRegistryMu.Unlock()
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if plugin == nil {
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panic("nil plugin passed to RegisterExtension")
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}
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if _, ok := pluginRegistry[name]; ok {
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panic("duplicate RegisterExtension name: " + name)
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}
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pluginRegistry[name] = plugin
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}
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/* BEGIN DYNAMIC SPECIFIC STUFF */
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var (
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pluginProvider PluginProvider = nil
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pluginProviderMu sync.RWMutex
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)
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type NamedPlugin struct {
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Name string
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Plugin Plugin
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}
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type PluginProvider interface {
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Add() <-chan NamedPlugin
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Remove() <-chan string
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// nil errors will be sent in response to successful calls to Add or Remove
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Err() chan<- error
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Done() <-chan struct{}
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}
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func RegisterPluginProvider(p PluginProvider) {
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pluginProviderMu.Lock()
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defer pluginProviderMu.Unlock()
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if pluginProvider != nil {
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panic("RegisterPluginProvider already called")
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}
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pluginProvider = p
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go func() {
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addCh := pluginProvider.Add()
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remCh := pluginProvider.Remove()
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errCh := pluginProvider.Err()
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doneCh := pluginProvider.Done()
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for {
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select {
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case namedPlugin := <-addCh:
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pluginRegistryMu.Lock() // LOCK
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if _, ok := pluginRegistry[namedPlugin.Name]; ok {
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errCh <- fmt.Errorf("cannot add: plugin already registered: %s", namedPlugin.Name)
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} else {
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pluginRegistry[namedPlugin.Name] = namedPlugin.Plugin
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errCh <- nil
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}
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pluginRegistryMu.Unlock() // UNLOCK
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case removeName := <-remCh:
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pluginRegistryMu.Lock() // LOCK
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if _, ok := pluginRegistry[removeName]; !ok {
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errCh <- fmt.Errorf("cannot remove: plugin not registered: %s", removeName)
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} else {
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delete(pluginRegistry, removeName)
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errCh <- nil
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}
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pluginRegistryMu.Unlock() // UNLOCK
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case <-doneCh:
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close(errCh)
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return
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}
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}
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}()
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}
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