mirror of https://github.com/k3s-io/k3s
104 lines
3.4 KiB
Go
104 lines
3.4 KiB
Go
/*
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Copyright 2015 The Kubernetes Authors All rights reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package operationmanager
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import (
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"fmt"
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"sync"
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)
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// Operation Manager is a thread-safe interface for keeping track of multiple pending async operations.
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type OperationManager interface {
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// Called when the operation with the given ID has started.
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// Creates a new channel with specified buffer size tracked with the specified ID.
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// Returns a read-only version of the newly created channel.
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// Returns an error if an entry with the specified ID already exists (previous entry must be removed by calling Close).
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Start(id string, bufferSize uint) (<-chan interface{}, error)
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// Called when the operation with the given ID has terminated.
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// Closes and removes the channel associated with ID.
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// Returns an error if no associated channel exists.
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Close(id string) error
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// Attempts to send msg to the channel associated with ID.
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// Returns an error if no associated channel exists.
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Send(id string, msg interface{}) error
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// Returns true if an entry with the specified ID already exists.
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Exists(id string) bool
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}
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// Returns a new instance of a channel manager.
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func NewOperationManager() OperationManager {
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return &operationManager{
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chanMap: make(map[string]chan interface{}),
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}
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}
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type operationManager struct {
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sync.RWMutex
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chanMap map[string]chan interface{}
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}
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// Called when the operation with the given ID has started.
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// Creates a new channel with specified buffer size tracked with the specified ID.
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// Returns a read-only version of the newly created channel.
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// Returns an error if an entry with the specified ID already exists (previous entry must be removed by calling Close).
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func (cm *operationManager) Start(id string, bufferSize uint) (<-chan interface{}, error) {
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cm.Lock()
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defer cm.Unlock()
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if _, exists := cm.chanMap[id]; exists {
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return nil, fmt.Errorf("id %q already exists", id)
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}
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cm.chanMap[id] = make(chan interface{}, bufferSize)
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return cm.chanMap[id], nil
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}
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// Called when the operation with the given ID has terminated.
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// Closes and removes the channel associated with ID.
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// Returns an error if no associated channel exists.
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func (cm *operationManager) Close(id string) error {
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cm.Lock()
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defer cm.Unlock()
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if _, exists := cm.chanMap[id]; !exists {
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return fmt.Errorf("id %q not found", id)
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}
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close(cm.chanMap[id])
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delete(cm.chanMap, id)
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return nil
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}
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// Attempts to send msg to the channel associated with ID.
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// Returns an error if no associated channel exists.
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func (cm *operationManager) Send(id string, msg interface{}) error {
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cm.RLock()
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defer cm.RUnlock()
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if _, exists := cm.chanMap[id]; !exists {
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return fmt.Errorf("id %q not found", id)
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}
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cm.chanMap[id] <- msg
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return nil
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}
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// Returns true if an entry with the specified ID already exists.
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func (cm *operationManager) Exists(id string) (exists bool) {
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cm.RLock()
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defer cm.RUnlock()
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_, exists = cm.chanMap[id]
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return
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}
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