MT#7347 added reference counting to plug-in interfaces.

Fixes crash on restart. Included upstream commits:

commit b9cda79c435fc002c259b5430e61c45d8e94aa2c
Author: Raphael Coeffic <rco@iptel.org>
Date:   Sun Apr 28 14:27:27 2013 +0200

    sip: add reference counting to transport sockets

    allows for dynamic socket creation/deletion.

commit 73490566761bb0fb09a6ebd74566d7f2b789c62f
Author: Raphael Coeffic <rco@iptel.org>
Date:   Tue Nov 20 15:33:35 2012 +0100

    c/f: correcting some strange scope issues encountered with GCC & clang on osx.

commit 0b2c8068a980058ff34655bc4928aeaedbe527d7
Author: Stefan Sayer <stefan.sayer@googlemail.com>
Date:   Thu Jan 5 22:10:52 2012 +0100

    b/f: don't delete registered app objects, e.g. DSM apps

    fixes bug #68
    https://bugtracker.iptel.org/view.php?id=68

apps/db_reg_agent/DBRegAgent.h

@@ -157,6 +157,11 @@ class DBRegAgent
 
   int onLoad();
 
+  // atomic_ref_cnt interface
+  void on_destroy() {
+    onUnload();
+  }
+
   void onUnload();
 
   RegistrationTimer registration_scheduler;

apps/ivr/Ivr.cpp

@@ -41,7 +41,9 @@
 #include <dirent.h>
 
 #include <set>
+#include <string>
 using std::set;
+using std::string;
 
 
 #define PYFILE_REGEX "(.+)\\.(py|pyc|pyo)$"
@@ -461,7 +463,7 @@ int IvrFactory::onLoad()
 
   DBG("directory '%s' opened\n",script_path.c_str());
 
-  set<string> unique_entries;
+  std::set<string> unique_entries;
   regmatch_t  pmatch[2];
 
   struct dirent* entry=0;
@@ -479,7 +481,7 @@ int IvrFactory::onLoad()
   regfree(&reg);
 
   AmPlugIn* plugin = AmPlugIn::instance();
-  for(set<string>::iterator it = unique_entries.begin();
+  for(std::set<string>::iterator it = unique_entries.begin();
       it != unique_entries.end(); it++) {
 
     if(loadScript(*it)){

core/AmApi.h

@@ -35,6 +35,7 @@
 #include "AmConfigReader.h"
 #include "AmArg.h"
 #include "AmEventQueue.h"
+#include "atomic_types.h"
 
 #include <stdarg.h>
 
@@ -63,6 +64,7 @@ class AmDynInvoke
  * \brief Base interface for plugin factories
  */
 class AmPluginFactory
+  : public virtual atomic_ref_cnt
 {
   string plugin_name;
 
@@ -81,12 +83,6 @@ class AmPluginFactory
    * @return 1 on error.
    */
   virtual int onLoad()=0;
-
-
-  /**
-   * Enables the plug-in to deinitialize once the server is stopped.
-   */
-  virtual void onUnload() { };
 };
 
 /**

core/AmPlugIn.cpp

@@ -108,26 +108,17 @@ AmPlugIn::AmPlugIn()
 {
 }
 
-static std::set<AmPluginFactory*> deleted_factories;
-static std::set<string> deleted_factories_names;
 
 static void delete_plugin_factory(std::pair<string, AmPluginFactory*> pf)
 {
-  if ((deleted_factories.find(pf.second) == deleted_factories.end()) &&
-      (deleted_factories_names.find(pf.first) == deleted_factories_names.end())) {
-    DBG("onUnload of plugin '%s'\n", pf.first.c_str());
-    pf.second->onUnload();
+  DBG("decreasing reference to plug-in factory: %s\n", pf.first.c_str());
+  dec_ref(pf.second);
 
-    DBG("deleting plug-in factory: %s\n", pf.first.c_str());
-    deleted_factories.insert(pf.second);
-    deleted_factories_names.insert(pf.first);
-    delete pf.second;
-  }
 }
 
 AmPlugIn::~AmPlugIn()
 {
-  std::for_each(name2app.begin(), name2app.end(), delete_plugin_factory);
+  std::for_each(module_objects.begin(), module_objects.end(), delete_plugin_factory);
   std::for_each(name2seh.begin(), name2seh.end(), delete_plugin_factory);
   std::for_each(name2base.begin(), name2base.end(), delete_plugin_factory);
   std::for_each(name2di.begin(), name2di.end(), delete_plugin_factory);
@@ -566,6 +557,11 @@ int AmPlugIn::loadAppPlugIn(AmPluginFactory* f)
   name2app.insert(std::make_pair(sf->getName(),sf));
   DBG("application '%s' loaded.\n",sf->getName().c_str());
 
+  inc_ref(sf);
+  if(!module_objects.insert(std::make_pair(sf->getName(),sf)).second){
+    // insertion failed
+    dec_ref(sf);
+  }
   name2app_mut.unlock();
 
   return 0;
@@ -584,7 +580,8 @@ int AmPlugIn::loadSehPlugIn(AmPluginFactory* f)
     ERROR("session component '%s' already loaded !\n",sf->getName().c_str());
     goto error;
   }
-      
+
+  inc_ref(sf);
   name2seh.insert(std::make_pair(sf->getName(),sf));
   DBG("session component '%s' loaded.\n",sf->getName().c_str());
 
@@ -596,7 +593,11 @@ int AmPlugIn::loadSehPlugIn(AmPluginFactory* f)
 
 int AmPlugIn::loadBasePlugIn(AmPluginFactory* f)
 {
-  name2base.insert(std::make_pair(f->getName(),f));
+  inc_ref(f);
+  if(!name2base.insert(std::make_pair(f->getName(),f)).second){
+    // insertion failed
+    dec_ref(f);
+  }
   return 0;
 }
 
@@ -812,7 +813,7 @@ AmSessionFactory* AmPlugIn::findSessionFactory(AmSipRequest& req)
   ERROR(comp_name "'%s' already registered !\n", param_name.c_str());	\
   return false;								\
   }									\
-									\
+  inc_ref(f);								\
   instance()->map_name.insert(std::make_pair(param_name,f));		\
   DBG(comp_name " '%s' registered.\n",param_name.c_str());		\
   return true;

core/AmPlugIn.h

@@ -101,6 +101,8 @@ class AmPlugIn : public AmPayloadProviderInterface
   std::map<string,AmDynInvokeFactory*>           name2di;
   std::map<string,AmLoggingFacility*>            name2logfac;
 
+  std::map<string,AmPluginFactory*>             module_objects;
+
   //AmCtrlInterfaceFactory *ctrlIface;
 
   int dynamic_pl; // range: 96->127, see RFC 1890

core/atomic_types.h

@@ -198,6 +198,7 @@ protected:
     : atomic_int() {}
 
   virtual ~atomic_ref_cnt() {}
+  virtual void on_destroy() {}
 
   friend void inc_ref(atomic_ref_cnt* rc);
   friend void dec_ref(atomic_ref_cnt* rc);
@@ -212,8 +213,10 @@ inline void inc_ref(atomic_ref_cnt* rc)
 inline void dec_ref(atomic_ref_cnt* rc)
 {
   assert(rc);
-  if(rc->dec_and_test())
+  if(rc->dec_and_test()){
+    rc->on_destroy();
     delete rc;
+  }
 }