1 // Copyright 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef MOJO_COMMON_HANDLE_WATCHER_H_ 6 #define MOJO_COMMON_HANDLE_WATCHER_H_ 7 8 #include "base/basictypes.h" 9 #include "base/callback_forward.h" 10 #include "base/memory/scoped_ptr.h" 11 #include "base/run_loop.h" 12 #include "mojo/common/mojo_common_export.h" 13 #include "mojo/public/cpp/system/core.h" 14 15 namespace base { 16 class Thread; 17 } 18 19 namespace mojo { 20 namespace common { 21 namespace test { 22 class HandleWatcherTest; 23 } 24 25 // HandleWatcher is used to asynchronously wait on a handle and notify a Closure 26 // when the handle is ready, or the deadline has expired. 27 class MOJO_COMMON_EXPORT HandleWatcher { 28 public: 29 HandleWatcher(); 30 ~HandleWatcher(); 31 32 // Starts listening for |handle|. This implicitly invokes Stop(). In other 33 // words, Start() performs one asynchronous watch at a time. It is ok to call 34 // Start() multiple times, but it cancels any existing watches. |callback| is 35 // notified when the handle is ready, invalid or deadline has passed and is 36 // notified on the thread Start() was invoked on. If the current thread exits 37 // before the handle is ready, then |callback| is invoked with a result of 38 // MOJO_RESULT_ABORTED. 39 void Start(const Handle& handle, 40 MojoHandleSignals handle_signals, 41 MojoDeadline deadline, 42 const base::Callback<void(MojoResult)>& callback); 43 44 // Stops listening. Does nothing if not in the process of listening. 45 void Stop(); 46 47 private: 48 class State; 49 50 // If non-NULL Start() has been invoked. 51 scoped_ptr<State> state_; 52 53 DISALLOW_COPY_AND_ASSIGN(HandleWatcher); 54 }; 55 56 } // namespace common 57 } // namespace mojo 58 59 #endif // MOJO_COMMON_HANDLE_WATCHER_H_ 60
