1 /*
2 * Copyright 2004 The WebRTC Project Authors. All rights reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
11 #ifndef WEBRTC_BASE_MESSAGEQUEUE_H_
12 #define WEBRTC_BASE_MESSAGEQUEUE_H_
13
14 #include <string.h>
15
16 #include <algorithm>
17 #include <list>
18 #include <queue>
19 #include <vector>
20
21 #include "webrtc/base/basictypes.h"
22 #include "webrtc/base/constructormagic.h"
23 #include "webrtc/base/criticalsection.h"
24 #include "webrtc/base/messagehandler.h"
25 #include "webrtc/base/scoped_ptr.h"
26 #include "webrtc/base/scoped_ref_ptr.h"
27 #include "webrtc/base/sigslot.h"
28 #include "webrtc/base/socketserver.h"
29 #include "webrtc/base/timeutils.h"
30
31 namespace rtc {
32
33 struct Message;
34 class MessageQueue;
35
36 // MessageQueueManager does cleanup of of message queues
37
38 class MessageQueueManager {
39 public:
40 static void Add(MessageQueue *message_queue);
41 static void Remove(MessageQueue *message_queue);
42 static void Clear(MessageHandler *handler);
43
44 // For testing purposes, we expose whether or not the MessageQueueManager
45 // instance has been initialized. It has no other use relative to the rest of
46 // the functions of this class, which auto-initialize the underlying
47 // MessageQueueManager instance when necessary.
48 static bool IsInitialized();
49
50 private:
51 static MessageQueueManager* Instance();
52
53 MessageQueueManager();
54 ~MessageQueueManager();
55
56 void AddInternal(MessageQueue *message_queue);
57 void RemoveInternal(MessageQueue *message_queue);
58 void ClearInternal(MessageHandler *handler);
59
60 static MessageQueueManager* instance_;
61 // This list contains all live MessageQueues.
62 std::vector<MessageQueue *> message_queues_;
63 CriticalSection crit_;
64 };
65
66 // Derive from this for specialized data
67 // App manages lifetime, except when messages are purged
68
69 class MessageData {
70 public:
MessageData()71 MessageData() {}
~MessageData()72 virtual ~MessageData() {}
73 };
74
75 template <class T>
76 class TypedMessageData : public MessageData {
77 public:
TypedMessageData(const T & data)78 explicit TypedMessageData(const T& data) : data_(data) { }
data()79 const T& data() const { return data_; }
data()80 T& data() { return data_; }
81 private:
82 T data_;
83 };
84
85 // Like TypedMessageData, but for pointers that require a delete.
86 template <class T>
87 class ScopedMessageData : public MessageData {
88 public:
ScopedMessageData(T * data)89 explicit ScopedMessageData(T* data) : data_(data) { }
data()90 const scoped_ptr<T>& data() const { return data_; }
data()91 scoped_ptr<T>& data() { return data_; }
92 private:
93 scoped_ptr<T> data_;
94 };
95
96 // Like ScopedMessageData, but for reference counted pointers.
97 template <class T>
98 class ScopedRefMessageData : public MessageData {
99 public:
ScopedRefMessageData(T * data)100 explicit ScopedRefMessageData(T* data) : data_(data) { }
data()101 const scoped_refptr<T>& data() const { return data_; }
data()102 scoped_refptr<T>& data() { return data_; }
103 private:
104 scoped_refptr<T> data_;
105 };
106
107 template<class T>
WrapMessageData(const T & data)108 inline MessageData* WrapMessageData(const T& data) {
109 return new TypedMessageData<T>(data);
110 }
111
112 template<class T>
UseMessageData(MessageData * data)113 inline const T& UseMessageData(MessageData* data) {
114 return static_cast< TypedMessageData<T>* >(data)->data();
115 }
116
117 template<class T>
118 class DisposeData : public MessageData {
119 public:
DisposeData(T * data)120 explicit DisposeData(T* data) : data_(data) { }
~DisposeData()121 virtual ~DisposeData() { delete data_; }
122 private:
123 T* data_;
124 };
125
126 const uint32_t MQID_ANY = static_cast<uint32_t>(-1);
127 const uint32_t MQID_DISPOSE = static_cast<uint32_t>(-2);
128
129 // No destructor
130
131 struct Message {
MessageMessage132 Message() {
133 memset(this, 0, sizeof(*this));
134 }
MatchMessage135 inline bool Match(MessageHandler* handler, uint32_t id) const {
136 return (handler == NULL || handler == phandler)
137 && (id == MQID_ANY || id == message_id);
138 }
139 MessageHandler *phandler;
140 uint32_t message_id;
141 MessageData *pdata;
142 uint32_t ts_sensitive;
143 };
144
145 typedef std::list<Message> MessageList;
146
147 // DelayedMessage goes into a priority queue, sorted by trigger time. Messages
148 // with the same trigger time are processed in num_ (FIFO) order.
149
150 class DelayedMessage {
151 public:
DelayedMessage(int delay,uint32_t trigger,uint32_t num,const Message & msg)152 DelayedMessage(int delay, uint32_t trigger, uint32_t num, const Message& msg)
153 : cmsDelay_(delay), msTrigger_(trigger), num_(num), msg_(msg) {}
154
155 bool operator< (const DelayedMessage& dmsg) const {
156 return (dmsg.msTrigger_ < msTrigger_)
157 || ((dmsg.msTrigger_ == msTrigger_) && (dmsg.num_ < num_));
158 }
159
160 int cmsDelay_; // for debugging
161 uint32_t msTrigger_;
162 uint32_t num_;
163 Message msg_;
164 };
165
166 class MessageQueue {
167 public:
168 static const int kForever = -1;
169
170 explicit MessageQueue(SocketServer* ss = NULL);
171 virtual ~MessageQueue();
172
socketserver()173 SocketServer* socketserver() { return ss_; }
174 void set_socketserver(SocketServer* ss);
175
176 // Note: The behavior of MessageQueue has changed. When a MQ is stopped,
177 // futher Posts and Sends will fail. However, any pending Sends and *ready*
178 // Posts (as opposed to unexpired delayed Posts) will be delivered before
179 // Get (or Peek) returns false. By guaranteeing delivery of those messages,
180 // we eliminate the race condition when an MessageHandler and MessageQueue
181 // may be destroyed independently of each other.
182 virtual void Quit();
183 virtual bool IsQuitting();
184 virtual void Restart();
185
186 // Get() will process I/O until:
187 // 1) A message is available (returns true)
188 // 2) cmsWait seconds have elapsed (returns false)
189 // 3) Stop() is called (returns false)
190 virtual bool Get(Message *pmsg, int cmsWait = kForever,
191 bool process_io = true);
192 virtual bool Peek(Message *pmsg, int cmsWait = 0);
193 virtual void Post(MessageHandler* phandler,
194 uint32_t id = 0,
195 MessageData* pdata = NULL,
196 bool time_sensitive = false);
197 virtual void PostDelayed(int cmsDelay,
198 MessageHandler* phandler,
199 uint32_t id = 0,
200 MessageData* pdata = NULL);
201 virtual void PostAt(uint32_t tstamp,
202 MessageHandler* phandler,
203 uint32_t id = 0,
204 MessageData* pdata = NULL);
205 virtual void Clear(MessageHandler* phandler,
206 uint32_t id = MQID_ANY,
207 MessageList* removed = NULL);
208 virtual void Dispatch(Message *pmsg);
209 virtual void ReceiveSends();
210
211 // Amount of time until the next message can be retrieved
212 virtual int GetDelay();
213
empty()214 bool empty() const { return size() == 0u; }
size()215 size_t size() const {
216 CritScope cs(&crit_); // msgq_.size() is not thread safe.
217 return msgq_.size() + dmsgq_.size() + (fPeekKeep_ ? 1u : 0u);
218 }
219
220 // Internally posts a message which causes the doomed object to be deleted
Dispose(T * doomed)221 template<class T> void Dispose(T* doomed) {
222 if (doomed) {
223 Post(NULL, MQID_DISPOSE, new DisposeData<T>(doomed));
224 }
225 }
226
227 // When this signal is sent out, any references to this queue should
228 // no longer be used.
229 sigslot::signal0<> SignalQueueDestroyed;
230
231 protected:
232 class PriorityQueue : public std::priority_queue<DelayedMessage> {
233 public:
container()234 container_type& container() { return c; }
reheap()235 void reheap() { make_heap(c.begin(), c.end(), comp); }
236 };
237
238 void DoDelayPost(int cmsDelay,
239 uint32_t tstamp,
240 MessageHandler* phandler,
241 uint32_t id,
242 MessageData* pdata);
243
244 // The SocketServer is not owned by MessageQueue.
245 SocketServer* ss_;
246 // If a server isn't supplied in the constructor, use this one.
247 scoped_ptr<SocketServer> default_ss_;
248 bool fStop_;
249 bool fPeekKeep_;
250 Message msgPeek_;
251 MessageList msgq_;
252 PriorityQueue dmsgq_;
253 uint32_t dmsgq_next_num_;
254 mutable CriticalSection crit_;
255
256 private:
257 RTC_DISALLOW_COPY_AND_ASSIGN(MessageQueue);
258 };
259
260 } // namespace rtc
261
262 #endif // WEBRTC_BASE_MESSAGEQUEUE_H_
263