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_XMPP_MODULEIMPL_H_
29#define TALK_XMPP_MODULEIMPL_H_
30
31#include "talk/xmpp/module.h"
32#include "talk/xmpp/xmppengine.h"
33
34namespace buzz {
35
36//! This is the base implementation class for extension modules.
37//! An engine is registered with the module and the module then hooks the
38//! appropriate parts of the engine to implement that set of features.  It is
39//! important to unregister modules before destructing the engine.
40class XmppModuleImpl {
41protected:
42  XmppModuleImpl();
43  virtual ~XmppModuleImpl();
44
45  //! Register the engine with the module.  Only one engine can be associated
46  //! with a module at a time.  This method will return an error if there is
47  //! already an engine registered.
48  XmppReturnStatus RegisterEngine(XmppEngine* engine);
49
50  //! Gets the engine that this module is attached to.
51  XmppEngine* engine();
52
53  //! Process the given stanza.
54  //! The module must return true if it has handled the stanza.
55  //! A false return value causes the stanza to be passed on to
56  //! the next registered handler.
57  virtual bool HandleStanza(const XmlElement *) { return false; };
58
59private:
60
61  //! The ModuleSessionHelper nested class allows the Module
62  //! to hook into and get stanzas and events from the engine.
63  class ModuleStanzaHandler : public XmppStanzaHandler {
64    friend class XmppModuleImpl;
65
66    ModuleStanzaHandler(XmppModuleImpl* module) :
67      module_(module) {
68    }
69
70    bool HandleStanza(const XmlElement* stanza) {
71      return module_->HandleStanza(stanza);
72    }
73
74    XmppModuleImpl* module_;
75  };
76
77  friend class ModuleStanzaHandler;
78
79  XmppEngine* engine_;
80  ModuleStanzaHandler stanza_handler_;
81};
82
83
84// This macro will implement the XmppModule interface for a class
85// that derives from both XmppModuleImpl and XmppModule
86#define IMPLEMENT_XMPPMODULE \
87  XmppReturnStatus RegisterEngine(XmppEngine* engine) { \
88    return XmppModuleImpl::RegisterEngine(engine); \
89  }
90
91}
92
93#endif  // TALK_XMPP_MODULEIMPL_H_
94