jbates@chromium.org | 5d5b281 | 2012-06-29 07:57:30 +0900 | [diff] [blame] | 1 | // Copyright (c) 2012 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 BASE_RUN_LOOP_H_ |
| 6 | #define BASE_RUN_LOOP_H_ |
jbates@chromium.org | 5d5b281 | 2012-06-29 07:57:30 +0900 | [diff] [blame] | 7 | |
| 8 | #include "base/base_export.h" |
| 9 | #include "base/callback.h" |
| 10 | #include "base/memory/weak_ptr.h" |
| 11 | #include "base/message_loop.h" |
| 12 | |
| 13 | namespace base { |
| 14 | #if defined(OS_ANDROID) |
| 15 | class MessagePumpForUI; |
| 16 | #endif |
| 17 | |
rohitrao@chromium.org | dcc4902 | 2012-07-13 20:02:57 +0900 | [diff] [blame] | 18 | #if defined(OS_IOS) |
| 19 | class MessagePumpUIApplication; |
| 20 | #endif |
| 21 | |
jbates@chromium.org | 5d5b281 | 2012-06-29 07:57:30 +0900 | [diff] [blame] | 22 | // Helper class to Run a nested MessageLoop. Please do not use nested |
| 23 | // MessageLoops in production code! If you must, use this class instead of |
| 24 | // calling MessageLoop::Run/Quit directly. RunLoop::Run can only be called once |
| 25 | // per RunLoop lifetime. Create a RunLoop on the stack and call Run/Quit to run |
| 26 | // a nested MessageLoop. |
| 27 | class BASE_EXPORT RunLoop { |
| 28 | public: |
| 29 | RunLoop(); |
| 30 | #if !defined(OS_MACOSX) && !defined(OS_ANDROID) |
| 31 | explicit RunLoop(MessageLoop::Dispatcher* dispatcher); |
| 32 | #endif |
| 33 | ~RunLoop(); |
| 34 | |
| 35 | #if !defined(OS_MACOSX) && !defined(OS_ANDROID) |
| 36 | void set_dispatcher(MessageLoop::Dispatcher* dispatcher) { |
| 37 | dispatcher_ = dispatcher; |
| 38 | } |
| 39 | #endif |
| 40 | |
| 41 | // Run the current MessageLoop. This blocks until Quit is called. Before |
| 42 | // calling Run, be sure to grab an AsWeakPtr or the QuitClosure in order to |
| 43 | // stop the MessageLoop asynchronously. MessageLoop::Quit and QuitNow will |
| 44 | // also trigger a return from Run, but those are deprecated. |
| 45 | void Run(); |
| 46 | |
| 47 | // Run the current MessageLoop until it doesn't find any tasks or messages in |
| 48 | // the queue (it goes idle). WARNING: This may never return! Only use this |
| 49 | // when repeating tasks such as animated web pages have been shut down. |
| 50 | void RunUntilIdle(); |
| 51 | |
| 52 | bool running() const { return running_; } |
| 53 | |
| 54 | // Quit an earlier call to Run(). There can be other nested RunLoops servicing |
| 55 | // the same task queue (MessageLoop); Quitting one RunLoop has no bearing on |
| 56 | // the others. Quit can be called before, during or after Run. If called |
| 57 | // before Run, Run will return immediately when called. Calling Quit after the |
| 58 | // RunLoop has already finished running has no effect. |
| 59 | // |
| 60 | // WARNING: You must NEVER assume that a call to Quit will terminate the |
| 61 | // targetted message loop. If a nested message loop continues running, the |
| 62 | // target may NEVER terminate. It is very easy to livelock (run forever) in |
| 63 | // such a case. |
| 64 | void Quit(); |
| 65 | |
| 66 | // Convenience method to get a closure that safely calls Quit (has no effect |
| 67 | // if the RunLoop instance is gone). |
| 68 | // |
| 69 | // Example: |
| 70 | // RunLoop run_loop; |
| 71 | // PostTask(run_loop.QuitClosure()); |
| 72 | // run_loop.Run(); |
| 73 | base::Closure QuitClosure(); |
| 74 | |
| 75 | private: |
xhwang@chromium.org | ff47fa5 | 2013-05-04 22:57:01 +0900 | [diff] [blame] | 76 | friend class MessageLoop; |
jbates@chromium.org | 5d5b281 | 2012-06-29 07:57:30 +0900 | [diff] [blame] | 77 | #if defined(OS_ANDROID) |
| 78 | // Android doesn't support the blocking MessageLoop::Run, so it calls |
| 79 | // BeforeRun and AfterRun directly. |
| 80 | friend class base::MessagePumpForUI; |
| 81 | #endif |
| 82 | |
rohitrao@chromium.org | dcc4902 | 2012-07-13 20:02:57 +0900 | [diff] [blame] | 83 | #if defined(OS_IOS) |
| 84 | // iOS doesn't support the blocking MessageLoop::Run, so it calls |
| 85 | // BeforeRun directly. |
| 86 | friend class base::MessagePumpUIApplication; |
| 87 | #endif |
| 88 | |
jbates@chromium.org | 5d5b281 | 2012-06-29 07:57:30 +0900 | [diff] [blame] | 89 | // Return false to abort the Run. |
| 90 | bool BeforeRun(); |
| 91 | void AfterRun(); |
| 92 | |
| 93 | MessageLoop* loop_; |
| 94 | |
| 95 | // WeakPtrFactory for QuitClosure safety. |
| 96 | base::WeakPtrFactory<RunLoop> weak_factory_; |
| 97 | |
| 98 | // Parent RunLoop or NULL if this is the top-most RunLoop. |
| 99 | RunLoop* previous_run_loop_; |
| 100 | |
| 101 | #if !defined(OS_MACOSX) && !defined(OS_ANDROID) |
| 102 | MessageLoop::Dispatcher* dispatcher_; |
| 103 | #endif |
| 104 | |
| 105 | // Used to count how many nested Run() invocations are on the stack. |
| 106 | int run_depth_; |
| 107 | |
| 108 | bool run_called_; |
| 109 | bool quit_called_; |
| 110 | bool running_; |
| 111 | |
| 112 | // Used to record that QuitWhenIdle() was called on the MessageLoop, meaning |
| 113 | // that we should quit Run once it becomes idle. |
| 114 | bool quit_when_idle_received_; |
| 115 | |
| 116 | DISALLOW_COPY_AND_ASSIGN(RunLoop); |
| 117 | }; |
| 118 | |
| 119 | } // namespace base |
| 120 | |
| 121 | #endif // BASE_RUN_LOOP_H_ |