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 "mojo/common/mojo_common_export.h" 12 #include "mojo/public/system/core_cpp.h" 13 14 namespace base { 15 class Thread; 16 class TickClock; 17 class TimeTicks; 18 } 19 20 namespace mojo { 21 namespace common { 22 namespace test { 23 class HandleWatcherTest; 24 } 25 26 // HandleWatcher is used to asynchronously wait on a handle and notify a Closure 27 // when the handle is ready, or the deadline has expired. 28 class MOJO_COMMON_EXPORT HandleWatcher { 29 public: 30 HandleWatcher(); 31 ~HandleWatcher(); 32 33 // Starts listening for |handle|. This implicitly invokes Stop(). In other 34 // words, Start() performs one asynchronous watch at a time. It is ok to call 35 // Start() multiple times, but it cancels any existing watches. |callback| is 36 // notified when the handle is ready, invalid or deadline has passed and is 37 // notified on the thread Start() was invoked on. 38 void Start(const Handle& handle, 39 MojoWaitFlags wait_flags, 40 MojoDeadline deadline, 41 const base::Callback<void(MojoResult)>& callback); 42 43 // Stops listening. Does nothing if not in the process of listening. 44 void Stop(); 45 46 // Returns now. Used internally; generally not useful. 47 static base::TimeTicks NowTicks(); 48 49 // Converts a MojoDeadline into a TimeTicks. 50 static base::TimeTicks MojoDeadlineToTimeTicks(MojoDeadline deadline); 51 52 private: 53 friend class test::HandleWatcherTest; 54 struct StartState; 55 56 // See description of |StartState::weak_factory| for details. 57 void OnHandleReady(MojoResult result); 58 59 // If non-NULL Start() has been invoked. 60 scoped_ptr<StartState> start_state_; 61 62 // Used for getting the time. Only set by tests. 63 static base::TickClock* tick_clock_; 64 65 DISALLOW_COPY_AND_ASSIGN(HandleWatcher); 66 }; 67 68 } // namespace common 69 } // namespace mojo 70 71 #endif // MOJO_COMMON_HANDLE_WATCHER_H_ 72