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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef BASE_MESSAGE_LOOP_MESSAGE_PUMP_H_ | 5 #ifndef BASE_MESSAGE_LOOP_MESSAGE_PUMP_H_ |
6 #define BASE_MESSAGE_LOOP_MESSAGE_PUMP_H_ | 6 #define BASE_MESSAGE_LOOP_MESSAGE_PUMP_H_ |
7 | 7 |
8 #include "base/base_export.h" | 8 #include "base/base_export.h" |
9 #include "base/memory/ref_counted.h" | 9 #include "base/threading/non_thread_safe.h" |
10 | 10 |
11 namespace base { | 11 namespace base { |
12 | 12 |
13 class TimeTicks; | 13 class TimeTicks; |
14 | 14 |
15 class BASE_EXPORT MessagePump : public RefCountedThreadSafe<MessagePump> { | 15 class BASE_EXPORT MessagePump : public NonThreadSafe { |
16 public: | 16 public: |
17 // Please see the comments above the Run method for an illustration of how | 17 // Please see the comments above the Run method for an illustration of how |
18 // these delegate methods are used. | 18 // these delegate methods are used. |
19 class BASE_EXPORT Delegate { | 19 class BASE_EXPORT Delegate { |
20 public: | 20 public: |
21 virtual ~Delegate() {} | 21 virtual ~Delegate() {} |
22 | 22 |
23 // Called from within Run in response to ScheduleWork or when the message | 23 // Called from within Run in response to ScheduleWork or when the message |
24 // pump would otherwise call DoDelayedWork. Returns true to indicate that | 24 // pump would otherwise call DoDelayedWork. Returns true to indicate that |
25 // work was done. DoDelayedWork will still be called if DoWork returns | 25 // work was done. DoDelayedWork will still be called if DoWork returns |
26 // true, but DoIdleWork will not. | 26 // true, but DoIdleWork will not. |
27 virtual bool DoWork() = 0; | 27 virtual bool DoWork() = 0; |
28 | 28 |
29 // Called from within Run in response to ScheduleDelayedWork or when the | 29 // Called from within Run in response to ScheduleDelayedWork or when the |
30 // message pump would otherwise sleep waiting for more work. Returns true | 30 // message pump would otherwise sleep waiting for more work. Returns true |
31 // to indicate that delayed work was done. DoIdleWork will not be called | 31 // to indicate that delayed work was done. DoIdleWork will not be called |
32 // if DoDelayedWork returns true. Upon return |next_delayed_work_time| | 32 // if DoDelayedWork returns true. Upon return |next_delayed_work_time| |
33 // indicates the time when DoDelayedWork should be called again. If | 33 // indicates the time when DoDelayedWork should be called again. If |
34 // |next_delayed_work_time| is null (per Time::is_null), then the queue of | 34 // |next_delayed_work_time| is null (per Time::is_null), then the queue of |
35 // future delayed work (timer events) is currently empty, and no additional | 35 // future delayed work (timer events) is currently empty, and no additional |
36 // calls to this function need to be scheduled. | 36 // calls to this function need to be scheduled. |
37 virtual bool DoDelayedWork(TimeTicks* next_delayed_work_time) = 0; | 37 virtual bool DoDelayedWork(TimeTicks* next_delayed_work_time) = 0; |
38 | 38 |
39 // Called from within Run just before the message pump goes to sleep. | 39 // Called from within Run just before the message pump goes to sleep. |
40 // Returns true to indicate that idle work was done. | 40 // Returns true to indicate that idle work was done. |
41 virtual bool DoIdleWork() = 0; | 41 virtual bool DoIdleWork() = 0; |
42 }; | 42 }; |
43 | 43 |
44 MessagePump(); | 44 MessagePump(); |
| 45 virtual ~MessagePump(); |
45 | 46 |
46 // The Run method is called to enter the message pump's run loop. | 47 // The Run method is called to enter the message pump's run loop. |
47 // | 48 // |
48 // Within the method, the message pump is responsible for processing native | 49 // Within the method, the message pump is responsible for processing native |
49 // messages as well as for giving cycles to the delegate periodically. The | 50 // messages as well as for giving cycles to the delegate periodically. The |
50 // message pump should take care to mix delegate callbacks with native | 51 // message pump should take care to mix delegate callbacks with native |
51 // message processing so neither type of event starves the other of cycles. | 52 // message processing so neither type of event starves the other of cycles. |
52 // | 53 // |
53 // The anatomy of a typical run loop: | 54 // The anatomy of a typical run loop: |
54 // | 55 // |
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111 // Schedule a DoWork callback to happen reasonably soon. Does nothing if a | 112 // Schedule a DoWork callback to happen reasonably soon. Does nothing if a |
112 // DoWork callback is already scheduled. This method may be called from any | 113 // DoWork callback is already scheduled. This method may be called from any |
113 // thread. Once this call is made, DoWork should not be "starved" at least | 114 // thread. Once this call is made, DoWork should not be "starved" at least |
114 // until it returns a value of false. | 115 // until it returns a value of false. |
115 virtual void ScheduleWork() = 0; | 116 virtual void ScheduleWork() = 0; |
116 | 117 |
117 // Schedule a DoDelayedWork callback to happen at the specified time, | 118 // Schedule a DoDelayedWork callback to happen at the specified time, |
118 // cancelling any pending DoDelayedWork callback. This method may only be | 119 // cancelling any pending DoDelayedWork callback. This method may only be |
119 // used on the thread that called Run. | 120 // used on the thread that called Run. |
120 virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time) = 0; | 121 virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time) = 0; |
121 | |
122 protected: | |
123 virtual ~MessagePump(); | |
124 friend class RefCountedThreadSafe<MessagePump>; | |
125 }; | 122 }; |
126 | 123 |
127 } // namespace base | 124 } // namespace base |
128 | 125 |
129 #endif // BASE_MESSAGE_LOOP_MESSAGE_PUMP_H_ | 126 #endif // BASE_MESSAGE_LOOP_MESSAGE_PUMP_H_ |
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