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      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 
     45 namespace talk_base {
     46 
     47 struct Message;
     48 class MessageQueue;
     49 
     50 // MessageQueueManager does cleanup of of message queues
     51 
     52 class 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 
     73 class MessageData {
     74  public:
     75   MessageData() {}
     76   virtual ~MessageData() {}
     77 };
     78 
     79 template <class T>
     80 class 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.
     90 template <class T>
     91 class 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 
    100 template<class T>
    101 inline MessageData* WrapMessageData(const T& data) {
    102   return new TypedMessageData<T>(data);
    103 }
    104 
    105 template<class T>
    106 inline const T& UseMessageData(MessageData* data) {
    107   return static_cast< TypedMessageData<T>* >(data)->data();
    108 }
    109 
    110 template<class T>
    111 class DisposeData : public MessageData {
    112  public:
    113   explicit DisposeData(T* data) : data_(data) { }
    114   virtual ~DisposeData() { delete data_; }
    115  private:
    116   T* data_;
    117 };
    118 
    119 const uint32 MQID_ANY = static_cast<uint32>(-1);
    120 const uint32 MQID_DISPOSE = static_cast<uint32>(-2);
    121 
    122 // No destructor
    123 
    124 struct 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 
    138 typedef 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 
    143 class 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 
    159 class 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