Adds a modified copy of talk/base to webrtc/base. It is the first step in
migrating talk/base to webrtc/base.
BUG=N/A
R=niklas.enbom@webrtc.org
Review URL: https://webrtc-codereview.appspot.com/17479005
git-svn-id: http://webrtc.googlecode.com/svn/trunk@6129 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/base/asyncinvoker.h b/webrtc/base/asyncinvoker.h
new file mode 100644
index 0000000..ee9a03c
--- /dev/null
+++ b/webrtc/base/asyncinvoker.h
@@ -0,0 +1,134 @@
+/*
+ * Copyright 2014 The WebRTC Project Authors. All rights reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_BASE_ASYNCINVOKER_H_
+#define WEBRTC_BASE_ASYNCINVOKER_H_
+
+#include "webrtc/base/asyncinvoker-inl.h"
+#include "webrtc/base/bind.h"
+#include "webrtc/base/sigslot.h"
+#include "webrtc/base/scopedptrcollection.h"
+#include "webrtc/base/thread.h"
+
+namespace rtc {
+
+// Invokes function objects (aka functors) asynchronously on a Thread, and
+// owns the lifetime of calls (ie, when this object is destroyed, calls in
+// flight are cancelled). AsyncInvoker can optionally execute a user-specified
+// function when the asynchronous call is complete, or operates in
+// fire-and-forget mode otherwise.
+//
+// AsyncInvoker does not own the thread it calls functors on.
+//
+// A note about async calls and object lifetimes: users should
+// be mindful of object lifetimes when calling functions asynchronously and
+// ensure objects used by the function _cannot_ be deleted between the
+// invocation and execution of the functor. AsyncInvoker is designed to
+// help: any calls in flight will be cancelled when the AsyncInvoker used to
+// make the call is destructed, and any calls executing will be allowed to
+// complete before AsyncInvoker destructs.
+//
+// The easiest way to ensure lifetimes are handled correctly is to create a
+// class that owns the Thread and AsyncInvoker objects, and then call its
+// methods asynchronously as needed.
+//
+// Example:
+// class MyClass {
+// public:
+// void FireAsyncTaskWithResult(Thread* thread, int x) {
+// // Specify a callback to get the result upon completion.
+// invoker_.AsyncInvoke<int>(
+// thread, Bind(&MyClass::AsyncTaskWithResult, this, x),
+// &MyClass::OnTaskComplete, this);
+// }
+// void FireAnotherAsyncTask(Thread* thread) {
+// // No callback specified means fire-and-forget.
+// invoker_.AsyncInvoke<void>(
+// thread, Bind(&MyClass::AnotherAsyncTask, this));
+//
+// private:
+// int AsyncTaskWithResult(int x) {
+// // Some long running process...
+// return x * x;
+// }
+// void AnotherAsyncTask() {
+// // Some other long running process...
+// }
+// void OnTaskComplete(int result) { result_ = result; }
+//
+// AsyncInvoker invoker_;
+// int result_;
+// };
+class AsyncInvoker : public MessageHandler {
+ public:
+ AsyncInvoker();
+ virtual ~AsyncInvoker();
+
+ // Call |functor| asynchronously on |thread|, with no callback upon
+ // completion. Returns immediately.
+ template <class ReturnT, class FunctorT>
+ void AsyncInvoke(Thread* thread,
+ const FunctorT& functor,
+ uint32 id = 0) {
+ AsyncClosure* closure =
+ new RefCountedObject<FireAndForgetAsyncClosure<FunctorT> >(functor);
+ DoInvoke(thread, closure, id);
+ }
+
+ // Call |functor| asynchronously on |thread|, calling |callback| when done.
+ template <class ReturnT, class FunctorT, class HostT>
+ void AsyncInvoke(Thread* thread,
+ const FunctorT& functor,
+ void (HostT::*callback)(ReturnT),
+ HostT* callback_host,
+ uint32 id = 0) {
+ AsyncClosure* closure =
+ new RefCountedObject<NotifyingAsyncClosure<ReturnT, FunctorT, HostT> >(
+ this, Thread::Current(), functor, callback, callback_host);
+ DoInvoke(thread, closure, id);
+ }
+
+ // Call |functor| asynchronously on |thread|, calling |callback| when done.
+ // Overloaded for void return.
+ template <class ReturnT, class FunctorT, class HostT>
+ void AsyncInvoke(Thread* thread,
+ const FunctorT& functor,
+ void (HostT::*callback)(),
+ HostT* callback_host,
+ uint32 id = 0) {
+ AsyncClosure* closure =
+ new RefCountedObject<NotifyingAsyncClosure<void, FunctorT, HostT> >(
+ this, Thread::Current(), functor, callback, callback_host);
+ DoInvoke(thread, closure, id);
+ }
+
+ // Synchronously execute on |thread| all outstanding calls we own
+ // that are pending on |thread|, and wait for calls to complete
+ // before returning. Optionally filter by message id.
+ // The destructor will not wait for outstanding calls, so if that
+ // behavior is desired, call Flush() before destroying this object.
+ void Flush(Thread* thread, uint32 id = MQID_ANY);
+
+ // Signaled when this object is destructed.
+ sigslot::signal0<> SignalInvokerDestroyed;
+
+ private:
+ virtual void OnMessage(Message* msg);
+ void DoInvoke(Thread* thread, AsyncClosure* closure, uint32 id);
+
+ bool destroying_;
+
+ DISALLOW_COPY_AND_ASSIGN(AsyncInvoker);
+};
+
+} // namespace rtc
+
+
+#endif // WEBRTC_BASE_ASYNCINVOKER_H_
