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 <algorithm>
32#include <cstring>
33#include <list>
34#include <queue>
35#include <vector>
36
37#include "talk/base/basictypes.h"
38#include "talk/base/criticalsection.h"
39#include "talk/base/messagehandler.h"
40#include "talk/base/scoped_ptr.h"
41#include "talk/base/sigslot.h"
42#include "talk/base/socketserver.h"
43#include "talk/base/time.h"
44
45namespace talk_base {
46
47struct Message;
48class MessageQueue;
49
50// MessageQueueManager does cleanup of of message queues
51
52class MessageQueueManager {
53 public:
54  static MessageQueueManager* Instance();
55
56  void Add(MessageQueue *message_queue);
57  void Remove(MessageQueue *message_queue);
58  void Clear(MessageHandler *handler);
59
60 private:
61  MessageQueueManager();
62  ~MessageQueueManager();
63
64  static MessageQueueManager* instance_;
65  // This list contains 'active' MessageQueues.
66  std::vector<MessageQueue *> message_queues_;
67  CriticalSection crit_;
68};
69
70// Derive from this for specialized data
71// App manages lifetime, except when messages are purged
72
73class MessageData {
74 public:
75  MessageData() {}
76  virtual ~MessageData() {}
77};
78
79template <class T>
80class TypedMessageData : public MessageData {
81 public:
82  explicit TypedMessageData(const T& data) : data_(data) { }
83  const T& data() const { return data_; }
84  T& data() { return data_; }
85 private:
86  T data_;
87};
88
89// Like TypedMessageData, but for pointers that require a delete.
90template <class T>
91class ScopedMessageData : public MessageData {
92 public:
93  explicit ScopedMessageData(T* data) : data_(data) { }
94  const scoped_ptr<T>& data() const { return data_; }
95  scoped_ptr<T>& data() { return data_; }
96 private:
97  scoped_ptr<T> data_;
98};
99
100template<class T>
101inline MessageData* WrapMessageData(const T& data) {
102  return new TypedMessageData<T>(data);
103}
104
105template<class T>
106inline const T& UseMessageData(MessageData* data) {
107  return static_cast< TypedMessageData<T>* >(data)->data();
108}
109
110template<class T>
111class DisposeData : public MessageData {
112 public:
113  explicit DisposeData(T* data) : data_(data) { }
114  virtual ~DisposeData() { delete data_; }
115 private:
116  T* data_;
117};
118
119const uint32 MQID_ANY = static_cast<uint32>(-1);
120const uint32 MQID_DISPOSE = static_cast<uint32>(-2);
121
122// No destructor
123
124struct Message {
125  Message() {
126    memset(this, 0, sizeof(*this));
127  }
128  inline bool Match(MessageHandler* handler, uint32 id) const {
129    return (handler == NULL || handler == phandler)
130           && (id == MQID_ANY || id == message_id);
131  }
132  MessageHandler *phandler;
133  uint32 message_id;
134  MessageData *pdata;
135  uint32 ts_sensitive;
136};
137
138typedef std::list<Message> MessageList;
139
140// DelayedMessage goes into a priority queue, sorted by trigger time.  Messages
141// with the same trigger time are processed in num_ (FIFO) order.
142
143class DelayedMessage {
144 public:
145  DelayedMessage(int delay, uint32 trigger, uint32 num, const Message& msg)
146  : cmsDelay_(delay), msTrigger_(trigger), num_(num), msg_(msg) { }
147
148  bool operator< (const DelayedMessage& dmsg) const {
149    return (dmsg.msTrigger_ < msTrigger_)
150           || ((dmsg.msTrigger_ == msTrigger_) && (dmsg.num_ < num_));
151  }
152
153  int cmsDelay_;  // for debugging
154  uint32 msTrigger_;
155  uint32 num_;
156  Message msg_;
157};
158
159class MessageQueue {
160 public:
161  explicit MessageQueue(SocketServer* ss = NULL);
162  virtual ~MessageQueue();
163
164  SocketServer* socketserver() { return ss_; }
165  void set_socketserver(SocketServer* ss);
166
167  // Note: The behavior of MessageQueue has changed.  When a MQ is stopped,
168  // futher Posts and Sends will fail.  However, any pending Sends and *ready*
169  // Posts (as opposed to unexpired delayed Posts) will be delivered before
170  // Get (or Peek) returns false.  By guaranteeing delivery of those messages,
171  // we eliminate the race condition when an MessageHandler and MessageQueue
172  // may be destroyed independently of each other.
173  virtual void Quit();
174  virtual bool IsQuitting();
175  virtual void Restart();
176
177  // Get() will process I/O until:
178  //  1) A message is available (returns true)
179  //  2) cmsWait seconds have elapsed (returns false)
180  //  3) Stop() is called (returns false)
181  virtual bool Get(Message *pmsg, int cmsWait = kForever,
182                   bool process_io = true);
183  virtual bool Peek(Message *pmsg, int cmsWait = 0);
184  virtual void Post(MessageHandler *phandler, uint32 id = 0,
185                    MessageData *pdata = NULL, bool time_sensitive = false);
186  virtual void PostDelayed(int cmsDelay, MessageHandler *phandler,
187                           uint32 id = 0, MessageData *pdata = NULL) {
188    return DoDelayPost(cmsDelay, TimeAfter(cmsDelay), phandler, id, pdata);
189  }
190  virtual void PostAt(uint32 tstamp, MessageHandler *phandler,
191                      uint32 id = 0, MessageData *pdata = NULL) {
192    return DoDelayPost(TimeUntil(tstamp), tstamp, phandler, id, pdata);
193  }
194  virtual void Clear(MessageHandler *phandler, uint32 id = MQID_ANY,
195                     MessageList* removed = NULL);
196  virtual void Dispatch(Message *pmsg);
197  virtual void ReceiveSends();
198
199  // Amount of time until the next message can be retrieved
200  virtual int GetDelay();
201
202  bool empty() const { return msgq_.empty() && dmsgq_.empty() && !fPeekKeep_; }
203  size_t size() const { return msgq_.size() + dmsgq_.size() + fPeekKeep_; }
204
205  // Internally posts a message which causes the doomed object to be deleted
206  template<class T> void Dispose(T* doomed) {
207    if (doomed) {
208      Post(NULL, MQID_DISPOSE, new DisposeData<T>(doomed));
209    }
210  }
211
212  // When this signal is sent out, any references to this queue should
213  // no longer be used.
214  sigslot::signal0<> SignalQueueDestroyed;
215
216 protected:
217  class PriorityQueue : public std::priority_queue<DelayedMessage> {
218   public:
219    container_type& container() { return c; }
220    void reheap() { make_heap(c.begin(), c.end(), comp); }
221  };
222
223  void EnsureActive();
224  void DoDelayPost(int cmsDelay, uint32 tstamp, MessageHandler *phandler,
225                   uint32 id, MessageData* pdata);
226
227  // The SocketServer is not owned by MessageQueue.
228  SocketServer* ss_;
229  // If a server isn't supplied in the constructor, use this one.
230  scoped_ptr<SocketServer> default_ss_;
231  bool fStop_;
232  bool fPeekKeep_;
233  Message msgPeek_;
234  // A message queue is active if it has ever had a message posted to it.
235  // This also corresponds to being in MessageQueueManager's global list.
236  bool active_;
237  MessageList msgq_;
238  PriorityQueue dmsgq_;
239  uint32 dmsgq_next_num_;
240  CriticalSection crit_;
241};
242
243}  // namespace talk_base
244
245#endif  // TALK_BASE_MESSAGEQUEUE_H_
246