1/*
2 * libjingle
3 * Copyright 2004--2005, Google Inc.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 *  1. Redistributions of source code must retain the above copyright notice,
9 *     this list of conditions and the following disclaimer.
10 *  2. Redistributions in binary form must reproduce the above copyright notice,
11 *     this list of conditions and the following disclaimer in the documentation
12 *     and/or other materials provided with the distribution.
13 *  3. The name of the author may not be used to endorse or promote products
14 *     derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#ifndef TALK_BASE_MESSAGEQUEUE_H_
29#define TALK_BASE_MESSAGEQUEUE_H_
30
31#include <string.h>
32
33#include <algorithm>
34#include <list>
35#include <queue>
36#include <vector>
37
38#include "talk/base/basictypes.h"
39#include "talk/base/constructormagic.h"
40#include "talk/base/criticalsection.h"
41#include "talk/base/messagehandler.h"
42#include "talk/base/scoped_ptr.h"
43#include "talk/base/scoped_ref_ptr.h"
44#include "talk/base/sigslot.h"
45#include "talk/base/socketserver.h"
46#include "talk/base/timeutils.h"
47
48namespace talk_base {
49
50struct Message;
51class MessageQueue;
52
53// MessageQueueManager does cleanup of of message queues
54
55class MessageQueueManager {
56 public:
57  static void Add(MessageQueue *message_queue);
58  static void Remove(MessageQueue *message_queue);
59  static void Clear(MessageHandler *handler);
60
61  // For testing purposes, we expose whether or not the MessageQueueManager
62  // instance has been initialized. It has no other use relative to the rest of
63  // the functions of this class, which auto-initialize the underlying
64  // MessageQueueManager instance when necessary.
65  static bool IsInitialized();
66
67 private:
68  static MessageQueueManager* Instance();
69
70  MessageQueueManager();
71  ~MessageQueueManager();
72
73  void AddInternal(MessageQueue *message_queue);
74  void RemoveInternal(MessageQueue *message_queue);
75  void ClearInternal(MessageHandler *handler);
76
77  static MessageQueueManager* instance_;
78  // This list contains all live MessageQueues.
79  std::vector<MessageQueue *> message_queues_;
80  CriticalSection crit_;
81};
82
83// Derive from this for specialized data
84// App manages lifetime, except when messages are purged
85
86class MessageData {
87 public:
88  MessageData() {}
89  virtual ~MessageData() {}
90};
91
92template <class T>
93class TypedMessageData : public MessageData {
94 public:
95  explicit TypedMessageData(const T& data) : data_(data) { }
96  const T& data() const { return data_; }
97  T& data() { return data_; }
98 private:
99  T data_;
100};
101
102// Like TypedMessageData, but for pointers that require a delete.
103template <class T>
104class ScopedMessageData : public MessageData {
105 public:
106  explicit ScopedMessageData(T* data) : data_(data) { }
107  const scoped_ptr<T>& data() const { return data_; }
108  scoped_ptr<T>& data() { return data_; }
109 private:
110  scoped_ptr<T> data_;
111};
112
113// Like ScopedMessageData, but for reference counted pointers.
114template <class T>
115class ScopedRefMessageData : public MessageData {
116 public:
117  explicit ScopedRefMessageData(T* data) : data_(data) { }
118  const scoped_refptr<T>& data() const { return data_; }
119  scoped_refptr<T>& data() { return data_; }
120 private:
121  scoped_refptr<T> data_;
122};
123
124template<class T>
125inline MessageData* WrapMessageData(const T& data) {
126  return new TypedMessageData<T>(data);
127}
128
129template<class T>
130inline const T& UseMessageData(MessageData* data) {
131  return static_cast< TypedMessageData<T>* >(data)->data();
132}
133
134template<class T>
135class DisposeData : public MessageData {
136 public:
137  explicit DisposeData(T* data) : data_(data) { }
138  virtual ~DisposeData() { delete data_; }
139 private:
140  T* data_;
141};
142
143const uint32 MQID_ANY = static_cast<uint32>(-1);
144const uint32 MQID_DISPOSE = static_cast<uint32>(-2);
145
146// No destructor
147
148struct Message {
149  Message() {
150    memset(this, 0, sizeof(*this));
151  }
152  inline bool Match(MessageHandler* handler, uint32 id) const {
153    return (handler == NULL || handler == phandler)
154           && (id == MQID_ANY || id == message_id);
155  }
156  MessageHandler *phandler;
157  uint32 message_id;
158  MessageData *pdata;
159  uint32 ts_sensitive;
160};
161
162typedef std::list<Message> MessageList;
163
164// DelayedMessage goes into a priority queue, sorted by trigger time.  Messages
165// with the same trigger time are processed in num_ (FIFO) order.
166
167class DelayedMessage {
168 public:
169  DelayedMessage(int delay, uint32 trigger, uint32 num, const Message& msg)
170  : cmsDelay_(delay), msTrigger_(trigger), num_(num), msg_(msg) { }
171
172  bool operator< (const DelayedMessage& dmsg) const {
173    return (dmsg.msTrigger_ < msTrigger_)
174           || ((dmsg.msTrigger_ == msTrigger_) && (dmsg.num_ < num_));
175  }
176
177  int cmsDelay_;  // for debugging
178  uint32 msTrigger_;
179  uint32 num_;
180  Message msg_;
181};
182
183class MessageQueue {
184 public:
185  explicit MessageQueue(SocketServer* ss = NULL);
186  virtual ~MessageQueue();
187
188  SocketServer* socketserver() { return ss_; }
189  void set_socketserver(SocketServer* ss);
190
191  // Note: The behavior of MessageQueue has changed.  When a MQ is stopped,
192  // futher Posts and Sends will fail.  However, any pending Sends and *ready*
193  // Posts (as opposed to unexpired delayed Posts) will be delivered before
194  // Get (or Peek) returns false.  By guaranteeing delivery of those messages,
195  // we eliminate the race condition when an MessageHandler and MessageQueue
196  // may be destroyed independently of each other.
197  virtual void Quit();
198  virtual bool IsQuitting();
199  virtual void Restart();
200
201  // Get() will process I/O until:
202  //  1) A message is available (returns true)
203  //  2) cmsWait seconds have elapsed (returns false)
204  //  3) Stop() is called (returns false)
205  virtual bool Get(Message *pmsg, int cmsWait = kForever,
206                   bool process_io = true);
207  virtual bool Peek(Message *pmsg, int cmsWait = 0);
208  virtual void Post(MessageHandler *phandler, uint32 id = 0,
209                    MessageData *pdata = NULL, bool time_sensitive = false);
210  virtual void PostDelayed(int cmsDelay, MessageHandler *phandler,
211                           uint32 id = 0, MessageData *pdata = NULL) {
212    return DoDelayPost(cmsDelay, TimeAfter(cmsDelay), phandler, id, pdata);
213  }
214  virtual void PostAt(uint32 tstamp, MessageHandler *phandler,
215                      uint32 id = 0, MessageData *pdata = NULL) {
216    return DoDelayPost(TimeUntil(tstamp), tstamp, phandler, id, pdata);
217  }
218  virtual void Clear(MessageHandler *phandler, uint32 id = MQID_ANY,
219                     MessageList* removed = NULL);
220  virtual void Dispatch(Message *pmsg);
221  virtual void ReceiveSends();
222
223  // Amount of time until the next message can be retrieved
224  virtual int GetDelay();
225
226  bool empty() const { return size() == 0u; }
227  size_t size() const {
228    CritScope cs(&crit_);  // msgq_.size() is not thread safe.
229    return msgq_.size() + dmsgq_.size() + (fPeekKeep_ ? 1u : 0u);
230  }
231
232  // Internally posts a message which causes the doomed object to be deleted
233  template<class T> void Dispose(T* doomed) {
234    if (doomed) {
235      Post(NULL, MQID_DISPOSE, new DisposeData<T>(doomed));
236    }
237  }
238
239  // When this signal is sent out, any references to this queue should
240  // no longer be used.
241  sigslot::signal0<> SignalQueueDestroyed;
242
243 protected:
244  class PriorityQueue : public std::priority_queue<DelayedMessage> {
245   public:
246    container_type& container() { return c; }
247    void reheap() { make_heap(c.begin(), c.end(), comp); }
248  };
249
250  void DoDelayPost(int cmsDelay, uint32 tstamp, MessageHandler *phandler,
251                   uint32 id, MessageData* pdata);
252
253  // The SocketServer is not owned by MessageQueue.
254  SocketServer* ss_;
255  // If a server isn't supplied in the constructor, use this one.
256  scoped_ptr<SocketServer> default_ss_;
257  bool fStop_;
258  bool fPeekKeep_;
259  Message msgPeek_;
260  MessageList msgq_;
261  PriorityQueue dmsgq_;
262  uint32 dmsgq_next_num_;
263  mutable CriticalSection crit_;
264
265 private:
266  DISALLOW_COPY_AND_ASSIGN(MessageQueue);
267};
268
269}  // namespace talk_base
270
271#endif  // TALK_BASE_MESSAGEQUEUE_H_
272