91 lines
1.5 KiB
Go
91 lines
1.5 KiB
Go
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package webrtc
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import (
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"container/list"
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"sync"
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)
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// Operation is a function
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type operation func()
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// Operations is a task executor.
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type operations struct {
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mu sync.Mutex
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busy bool
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ops *list.List
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}
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func newOperations() *operations {
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return &operations{
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ops: list.New(),
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}
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}
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// Enqueue adds a new action to be executed. If there are no actions scheduled,
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// the execution will start immediately in a new goroutine.
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func (o *operations) Enqueue(op operation) {
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if op == nil {
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return
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}
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o.mu.Lock()
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running := o.busy
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o.ops.PushBack(op)
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o.busy = true
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o.mu.Unlock()
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if !running {
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go o.start()
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}
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}
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// IsEmpty checks if there are tasks in the queue
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func (o *operations) IsEmpty() bool {
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o.mu.Lock()
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defer o.mu.Unlock()
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return o.ops.Len() == 0
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}
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// Done blocks until all currently enqueued operations are finished executing.
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// For more complex synchronization, use Enqueue directly.
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func (o *operations) Done() {
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var wg sync.WaitGroup
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wg.Add(1)
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o.Enqueue(func() {
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wg.Done()
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})
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wg.Wait()
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}
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func (o *operations) pop() func() {
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o.mu.Lock()
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defer o.mu.Unlock()
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if o.ops.Len() == 0 {
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return nil
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}
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e := o.ops.Front()
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o.ops.Remove(e)
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return e.Value.(operation)
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}
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func (o *operations) start() {
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defer func() {
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o.mu.Lock()
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defer o.mu.Unlock()
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if o.ops.Len() == 0 {
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o.busy = false
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return
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}
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// either a new operation was enqueued while we
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// were busy, or an operation panicked
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go o.start()
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}()
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fn := o.pop()
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for fn != nil {
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fn()
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fn = o.pop()
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}
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}
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