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1 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2006-2008 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_PUMP_LIBEVENT_H_ | 5 #ifndef BASE_MESSAGE_PUMP_LIBEVENT_H_ |
6 #define BASE_MESSAGE_PUMP_LIBEVENT_H_ | 6 #define BASE_MESSAGE_PUMP_LIBEVENT_H_ |
7 | 7 |
8 #include "base/message_pump.h" | 8 #include "base/message_pump.h" |
9 #include "base/scoped_ptr.h" | |
10 #include "base/time.h" | 9 #include "base/time.h" |
11 | 10 |
12 // Declare structs we need from libevent.h rather than including it | 11 // Declare structs we need from libevent.h rather than including it |
13 struct event_base; | 12 struct event_base; |
14 struct event; | 13 struct event; |
15 | 14 |
16 namespace base { | 15 namespace base { |
17 | 16 |
18 // Class to monitor sockets and issue callbacks when sockets are ready for I/O | 17 // Class to monitor sockets and issue callbacks when sockets are ready for I/O |
19 // TODO(dkegel): add support for background file IO somehow | 18 // TODO(dkegel): add support for background file IO somehow |
20 class MessagePumpLibevent : public MessagePump { | 19 class MessagePumpLibevent : public MessagePump { |
21 public: | 20 public: |
22 | 21 // Used with WatchSocket to asynchronously monitor the I/O readiness of a |
23 // Object returned by WatchFileDescriptor to manage further watching. | 22 // socket. |
24 class FileDescriptorWatcher { | |
25 public: | |
26 FileDescriptorWatcher(); | |
27 ~FileDescriptorWatcher(); // Implicitly calls StopWatching. | |
28 | |
29 // NOTE: These methods aren't called StartWatching()/StopWatching() to | |
30 // avoid confusion with the win32 ObjectWatcher class. | |
31 | |
32 // Stop watching the FD, always safe to call. No-op if there's nothing | |
33 // to do. | |
34 bool StopWatchingFileDescriptor(); | |
35 | |
36 private: | |
37 // Called by MessagePumpLibevent, ownership of |e| is transferred to this | |
38 // object. | |
39 // If this FileWatcher is already watching an event, the previous event is | |
40 // terminated and cleaned up here. | |
41 void Init(event* e, bool is_persistent); | |
42 friend class MessagePumpLibevent; | |
43 | |
44 private: | |
45 bool is_persistent_; // false if this event is one-shot. | |
46 scoped_ptr<event> event_; | |
47 DISALLOW_COPY_AND_ASSIGN(FileDescriptorWatcher); | |
48 }; | |
49 | |
50 // Used with WatchFileDescptor to asynchronously monitor the I/O readiness of | |
51 // a File Descriptor. | |
52 class Watcher { | 23 class Watcher { |
53 public: | 24 public: |
54 virtual ~Watcher() {} | 25 virtual ~Watcher() {} |
55 // Called from MessageLoop::Run when an FD can be read from/written to | 26 // Called from MessageLoop::Run when a ready socket is detected. |
56 // without blocking | 27 virtual void OnSocketReady(short eventmask) = 0; |
57 virtual void OnFileCanReadWithoutBlocking(int fd) = 0; | 28 }; |
58 virtual void OnFileCanWriteWithoutBlocking(int fd) = 0; | 29 |
| 30 // Used with WatchFileHandle to monitor I/O readiness for a File Handle. |
| 31 class FileWatcher { |
| 32 public: |
| 33 virtual ~FileWatcher() {} |
| 34 // Called from MessageLoop::Run when a non-blocking read/write can be made. |
| 35 virtual void OnFileReadReady(int fd) = 0; |
| 36 virtual void OnFileWriteReady(int fd) = 0; |
59 }; | 37 }; |
60 | 38 |
61 MessagePumpLibevent(); | 39 MessagePumpLibevent(); |
62 virtual ~MessagePumpLibevent(); | 40 virtual ~MessagePumpLibevent(); |
63 | 41 |
64 enum Mode { | 42 // Have the current thread's message loop watch for a ready socket. |
65 WATCH_READ, | 43 // Caller must provide a struct event for this socket for libevent's use. |
66 WATCH_WRITE, | 44 // The event and interest_mask fields are defined in libevent. |
67 WATCH_READ_WRITE | 45 // Returns true on success. |
68 }; | 46 // TODO(dkegel): hide libevent better; abstraction still too leaky |
| 47 // TODO(dkegel): better error handing |
| 48 // TODO(dkegel): switch to edge-triggered readiness notification |
| 49 void WatchSocket(int socket, short interest_mask, event* e, Watcher*); |
69 | 50 |
70 // Have the current thread's message loop watch for a a situation in which | 51 // TODO(playmobil): Merge this with WatchSocket(). |
71 // reading/writing to the FD can be performed without Blocking. | 52 void WatchFileHandle(int fd, short interest_mask, event* e, FileWatcher*); |
72 // Callers must provide a preallocated FileDescriptorWatcher object which | 53 |
73 // can later be used to manage the Lifetime of this event. | 54 // Stop watching a socket. |
74 // Returns true on success. | 55 // Event was previously initialized by WatchSocket. |
75 // TODO(dkegel): switch to edge-triggered readiness notification | 56 void UnwatchSocket(event* e); |
76 bool WatchFileDescriptor(int fd, | 57 |
77 bool persistent, | 58 // Stop watching a File Handle. |
78 Mode mode, | 59 // Event was previously initialized by WatchFileHandle. |
79 FileDescriptorWatcher *controller, | 60 void UnwatchFileHandle(event* e); |
80 Watcher *delegate); | |
81 | 61 |
82 // MessagePump methods: | 62 // MessagePump methods: |
83 virtual void Run(Delegate* delegate); | 63 virtual void Run(Delegate* delegate); |
84 virtual void Quit(); | 64 virtual void Quit(); |
85 virtual void ScheduleWork(); | 65 virtual void ScheduleWork(); |
86 virtual void ScheduleDelayedWork(const Time& delayed_work_time); | 66 virtual void ScheduleDelayedWork(const Time& delayed_work_time); |
87 | 67 |
88 private: | 68 private: |
89 | 69 |
90 // Risky part of constructor. Returns true on success. | 70 // Risky part of constructor. Returns true on success. |
91 bool Init(); | 71 bool Init(); |
92 | 72 |
93 // This flag is set to false when Run should return. | 73 // This flag is set to false when Run should return. |
94 bool keep_running_; | 74 bool keep_running_; |
95 | 75 |
96 // This flag is set when inside Run. | 76 // This flag is set when inside Run. |
97 bool in_run_; | 77 bool in_run_; |
98 | 78 |
99 // The time at which we should call DoDelayedWork. | 79 // The time at which we should call DoDelayedWork. |
100 Time delayed_work_time_; | 80 Time delayed_work_time_; |
101 | 81 |
102 // Libevent dispatcher. Watches all sockets registered with it, and sends | 82 // Libevent dispatcher. Watches all sockets registered with it, and sends |
103 // readiness callbacks when a socket is ready for I/O. | 83 // readiness callbacks when a socket is ready for I/O. |
104 event_base* event_base_; | 84 event_base* event_base_; |
105 | 85 |
106 // Called by libevent to tell us a registered FD can be read/written to. | 86 // Called by libevent to tell us a registered socket is ready |
107 static void OnLibeventNotification(int fd, short flags, | 87 static void OnReadinessNotification(int socket, short flags, void* context); |
108 void* context); | 88 |
| 89 // Called by libevent to tell us a registered fd is ready. |
| 90 static void OnFileReadReadinessNotification(int fd, short flags, |
| 91 void* context); |
| 92 static void OnFileWriteReadinessNotification(int fd, short flags, |
| 93 void* context); |
109 | 94 |
110 // Unix pipe used to implement ScheduleWork() | 95 // Unix pipe used to implement ScheduleWork() |
111 // ... callback; called by libevent inside Run() when pipe is ready to read | 96 // ... callback; called by libevent inside Run() when pipe is ready to read |
112 static void OnWakeup(int socket, short flags, void* context); | 97 static void OnWakeup(int socket, short flags, void* context); |
113 // ... write end; ScheduleWork() writes a single byte to it | 98 // ... write end; ScheduleWork() writes a single byte to it |
114 int wakeup_pipe_in_; | 99 int wakeup_pipe_in_; |
115 // ... read end; OnWakeup reads it and then breaks Run() out of its sleep | 100 // ... read end; OnWakeup reads it and then breaks Run() out of its sleep |
116 int wakeup_pipe_out_; | 101 int wakeup_pipe_out_; |
117 // ... libevent wrapper for read end | 102 // ... libevent wrapper for read end |
118 event* wakeup_event_; | 103 event* wakeup_event_; |
119 | 104 |
120 DISALLOW_COPY_AND_ASSIGN(MessagePumpLibevent); | 105 DISALLOW_COPY_AND_ASSIGN(MessagePumpLibevent); |
121 }; | 106 }; |
122 | 107 |
123 } // namespace base | 108 } // namespace base |
124 | 109 |
125 #endif // BASE_MESSAGE_PUMP_LIBEVENT_H_ | 110 #endif // BASE_MESSAGE_PUMP_LIBEVENT_H_ |
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