140 lines
4.5 KiB
C++
140 lines
4.5 KiB
C++
/*
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* Copyright 2014 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef WEBRTC_BASE_ASYNCINVOKER_INL_H_
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#define WEBRTC_BASE_ASYNCINVOKER_INL_H_
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#include "webrtc/base/bind.h"
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#include "webrtc/base/callback.h"
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#include "webrtc/base/criticalsection.h"
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#include "webrtc/base/messagehandler.h"
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#include "webrtc/base/refcount.h"
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#include "webrtc/base/scoped_ref_ptr.h"
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#include "webrtc/base/sigslot.h"
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#include "webrtc/base/thread.h"
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namespace rtc {
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class AsyncInvoker;
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// Helper class for AsyncInvoker. Runs a task and triggers a callback
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// on the calling thread if necessary. Instances are ref-counted so their
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// lifetime can be independent of AsyncInvoker.
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class AsyncClosure : public RefCountInterface {
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public:
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// Runs the asynchronous task, and triggers a callback to the calling
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// thread if needed. Should be called from the target thread.
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virtual void Execute() = 0;
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protected:
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~AsyncClosure() override {}
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};
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// Simple closure that doesn't trigger a callback for the calling thread.
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template <class FunctorT>
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class FireAndForgetAsyncClosure : public AsyncClosure {
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public:
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explicit FireAndForgetAsyncClosure(const FunctorT& functor)
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: functor_(functor) {}
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virtual void Execute() {
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functor_();
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}
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private:
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FunctorT functor_;
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};
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// Base class for closures that may trigger a callback for the calling thread.
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// Listens for the "destroyed" signals from the calling thread and the invoker,
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// and cancels the callback to the calling thread if either is destroyed.
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class NotifyingAsyncClosureBase : public AsyncClosure,
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public sigslot::has_slots<> {
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public:
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~NotifyingAsyncClosureBase() override;
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protected:
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NotifyingAsyncClosureBase(AsyncInvoker* invoker,
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const Location& callback_posted_from,
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Thread* calling_thread);
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void TriggerCallback();
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void SetCallback(const Callback0<void>& callback) {
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CritScope cs(&crit_);
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callback_ = callback;
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}
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bool CallbackCanceled() const { return calling_thread_ == NULL; }
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private:
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AsyncInvoker* invoker_;
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Location callback_posted_from_;
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Callback0<void> callback_;
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CriticalSection crit_;
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Thread* calling_thread_;
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void CancelCallback();
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};
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// Closures that have a non-void return value and require a callback.
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template <class ReturnT, class FunctorT, class HostT>
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class NotifyingAsyncClosure : public NotifyingAsyncClosureBase {
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public:
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NotifyingAsyncClosure(AsyncInvoker* invoker,
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const Location& callback_posted_from,
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Thread* calling_thread,
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const FunctorT& functor,
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void (HostT::*callback)(ReturnT),
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HostT* callback_host)
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: NotifyingAsyncClosureBase(invoker,
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callback_posted_from,
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calling_thread),
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functor_(functor),
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callback_(callback),
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callback_host_(callback_host) {}
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virtual void Execute() {
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ReturnT result = functor_();
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if (!CallbackCanceled()) {
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SetCallback(Callback0<void>(Bind(callback_, callback_host_, result)));
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TriggerCallback();
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}
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}
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private:
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FunctorT functor_;
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void (HostT::*callback_)(ReturnT);
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HostT* callback_host_;
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};
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// Closures that have a void return value and require a callback.
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template <class FunctorT, class HostT>
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class NotifyingAsyncClosure<void, FunctorT, HostT>
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: public NotifyingAsyncClosureBase {
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public:
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NotifyingAsyncClosure(AsyncInvoker* invoker,
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const Location& callback_posted_from,
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Thread* calling_thread,
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const FunctorT& functor,
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void (HostT::*callback)(),
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HostT* callback_host)
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: NotifyingAsyncClosureBase(invoker,
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callback_posted_from,
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calling_thread),
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functor_(functor) {
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SetCallback(Callback0<void>(Bind(callback, callback_host)));
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}
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virtual void Execute() {
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functor_();
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TriggerCallback();
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}
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private:
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FunctorT functor_;
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};
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} // namespace rtc
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#endif // WEBRTC_BASE_ASYNCINVOKER_INL_H_
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