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