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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_P2P_BASE_TRANSPORTCHANNEL_H_
     29 #define TALK_P2P_BASE_TRANSPORTCHANNEL_H_
     30 
     31 #include <string>
     32 #include "talk/base/basictypes.h"
     33 #include "talk/base/sigslot.h"
     34 #include "talk/base/socket.h"
     35 
     36 namespace cricket {
     37 
     38 class P2PTransportChannel;
     39 
     40 // A TransportChannel represents one logical stream of packets that are sent
     41 // between the two sides of a session.
     42 class TransportChannel: public sigslot::has_slots<> {
     43  public:
     44   TransportChannel(const std::string& name, const std::string &content_type)
     45       : name_(name), content_type_(content_type),
     46         readable_(false), writable_(false) {}
     47   virtual ~TransportChannel() {}
     48 
     49   // Returns the name of this channel.
     50   const std::string& name() const { return name_; }
     51   const std::string& content_type() const { return content_type_; }
     52 
     53   // Returns the readable and states of this channel.  Each time one of these
     54   // states changes, a signal is raised.  These states are aggregated by the
     55   // TransportManager.
     56   bool readable() const { return readable_; }
     57   bool writable() const { return writable_; }
     58   sigslot::signal1<TransportChannel*> SignalReadableState;
     59   sigslot::signal1<TransportChannel*> SignalWritableState;
     60 
     61   // Attempts to send the given packet.  The return value is < 0 on failure.
     62   virtual int SendPacket(const char *data, size_t len) = 0;
     63 
     64   // Sets a socket option on this channel.  Note that not all options are
     65   // supported by all transport types.
     66   virtual int SetOption(talk_base::Socket::Option opt, int value) = 0;
     67 
     68   // Returns the most recent error that occurred on this channel.
     69   virtual int GetError() = 0;
     70 
     71   // This hack is here to allow the SocketMonitor to downcast to the
     72   // P2PTransportChannel safely.
     73   // TODO: Generalize network monitoring.
     74   virtual P2PTransportChannel* GetP2PChannel() { return NULL; }
     75 
     76   // Signalled each time a packet is received  on this channel.
     77   sigslot::signal3<TransportChannel*, const char*, size_t> SignalReadPacket;
     78 
     79   // This signal occurs when there is a change in the way that packets are
     80   // being routed.  The address indicates the address of the first hop in the
     81   // new route, if this is known.  If this cannot be determined or is not well-
     82   // defined, then the channel may give an address of 0.
     83   sigslot::signal2<TransportChannel*, const talk_base::SocketAddress&>
     84       SignalRouteChange;
     85 
     86   // Invoked when the channel is being destroyed.
     87   sigslot::signal1<TransportChannel*> SignalDestroyed;
     88 
     89   // Debugging description of this transport channel.
     90   std::string ToString() const;
     91 
     92  protected:
     93   // Sets the readable state, signaling if necessary.
     94   void set_readable(bool readable);
     95 
     96   // Sets the writable state, signaling if necessary.
     97   void set_writable(bool writable);
     98 
     99  private:
    100   std::string name_;
    101   std::string content_type_;
    102   bool readable_;
    103   bool writable_;
    104 
    105   DISALLOW_EVIL_CONSTRUCTORS(TransportChannel);
    106 };
    107 
    108 }  // namespace cricket
    109 
    110 #endif  // TALK_P2P_BASE_TRANSPORTCHANNEL_H_
    111