[gstreamermm] Plug-ins: Speed up initialization by avoiding their loading on startup.

[Josà Alburquerque <jaalburqu src gnome org>]

commit 648b89f5fe715c7c96a5824df999e9f2acb6f220
Author: Josà Alburquerque <jaalburqu svn gnome org>
Date:   Fri Sep 14 16:31:10 2012 -0400

    Plug-ins: Speed up initialization by avoiding their loading on startup.
    
    	* tools/extra_defs_gen/generate_plugin_gmmproc_file.cc
    	(generate_hg_file): Use the new _NO_WRAP_INIT_REGISTRATION macro to
    	signal that the plug-ins should not be registered on startup by the
    	wrap_init() function.  Also use the new _CUSTOM_WRAP_FUNCTION in order
    	to implement a custom Glib::wrap() function for plug-ins that ensures
    	the registration of the wrap_new() function before calling
    	Glib::wrap_auto() to wrap a C object.
    	(generate_ccg_file): Modify the generation of the plug-in *_get_type()
    	functions so that when an object of the plug-in type is first created,
    	the plug-in's wrap_new() function is registered with the wrapping
    	system using the type obtained when the plug-in is first loaded.  Also
    	generate a custom Glib::wrap() function that ensures the registration
    	of the plug-in's wrap_new() function before calling Glib::wrap_auto().
    	This ensures that even if there is a C type of the plug-in, that even
    	that object can be properly wrapped.
    
    	Bug #684006.

 ChangeLog                                          |   22 ++++++++++++
 .../extra_defs_gen/generate_plugin_gmmproc_file.cc |   36 ++++++++++++++++----
 2 files changed, 51 insertions(+), 7 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 978c1f3..6fabe5f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,25 @@
+2012-09-14  Josà Alburquerque  <jaalburquerque gmail com>
+
+	Plug-ins: Speed up initialization by avoiding their loading on startup.
+
+	* tools/extra_defs_gen/generate_plugin_gmmproc_file.cc
+	(generate_hg_file): Use the new _NO_WRAP_INIT_REGISTRATION macro to
+	signal that the plug-ins should not be registered on startup by the
+	wrap_init() function.  Also use the new _CUSTOM_WRAP_FUNCTION in order
+	to implement a custom Glib::wrap() function for plug-ins that ensures
+	the registration of the wrap_new() function before calling
+	Glib::wrap_auto() to wrap a C object.
+	(generate_ccg_file): Modify the generation of the plug-in *_get_type()
+	functions so that when an object of the plug-in type is first created,
+	the plug-in's wrap_new() function is registered with the wrapping
+	system using the type obtained when the plug-in is first loaded.  Also
+	generate a custom Glib::wrap() function that ensures the registration
+	of the plug-in's wrap_new() function before calling Glib::wrap_auto().
+	This ensures that even if there is a C type of the plug-in, that even
+	that object can be properly wrapped.
+
+	Bug #684006.
+
 2012-09-12  Josà Alburquerque  <jaalburquerque gmail com>
 
 	Event, Message, Query: Have create() methods return derived types.
diff --git a/tools/extra_defs_gen/generate_plugin_gmmproc_file.cc b/tools/extra_defs_gen/generate_plugin_gmmproc_file.cc
index 9eaf3f0..b89d1f9 100644
--- a/tools/extra_defs_gen/generate_plugin_gmmproc_file.cc
+++ b/tools/extra_defs_gen/generate_plugin_gmmproc_file.cc
@@ -648,12 +648,9 @@ static void generate_hg_file(const std::string& includeMacroCalls,
     std::cout << enumWrapStatements;
 
   std::cout << "/** A Wrapper for the " << pluginName << " plugin." << std::endl;
-  std::cout << " * Please note that, though using the underlying GObject is "
-    "fine, using its C\n * <B>type</B> is not guaranteed to be API stable "
-    "across releases because it is\n * not guaranteed to always remain the "
-    "same.  Also, not all plug-ins are\n * available on all systems so care "
-    "must be taken that they exist before they\n * are used, otherwise there "
-    "will be errors and possibly a crash." << std::endl;
+  std::cout << " * Please note that not all plug-ins are available on all "
+    "systems so care\n * must be taken that they exist before they are used "
+    "otherwise there will\n * be errors and possibly a crash." << std::endl;
   std::cout << " *" << std::endl;
   std::cout << " * @ingroup " << nmspace << "Plugins" << std::endl;
   std::cout << " */" << std::endl;
@@ -673,7 +670,9 @@ static void generate_hg_file(const std::string& includeMacroCalls,
   if(!interfaceMacros.empty())
     std::cout << interfaceMacros << std::endl;
 
-  std::cout << "  _IS_GSTREAMERMM_PLUGIN" << std::endl << std::endl;
+  std::cout << "  _IS_GSTREAMERMM_PLUGIN" << std::endl;
+  std::cout << "  _NO_WRAP_INIT_REGISTRATION" << std::endl;
+  std::cout << "  _CUSTOM_WRAP_FUNCTION" << std::endl << std::endl;
 
   std::cout << "protected:" << std::endl;
   std::cout << "  " << cppTypeName << "();" << std::endl;
@@ -739,6 +738,9 @@ static void generate_ccg_file(const std::string& enumGTypeFunctionDefinitions,
   std::cout << "      factory = GST_ELEMENT_FACTORY(feature);" << std::endl;
   std::cout << "      type = gst_element_factory_get_element_type(factory);" << std::endl;
   std::cout << "      g_object_unref(factory);" << std::endl;
+  std::cout << std::endl;
+  std::cout << "      // Register the new type with wrapping system" << std::endl;
+  std::cout << "      Glib::wrap_register(type, &" << nmspace << "::" << cppTypeName << "_Class::wrap_new);" << std::endl;
   std::cout << "    }" << std::endl;
   std::cout << "  }" << std::endl << std::endl;
 
@@ -763,6 +765,26 @@ static void generate_ccg_file(const std::string& enumGTypeFunctionDefinitions,
     std::cout << actionSignalsMethodDefinitions;
 
   std::cout << '}' << std::endl;
+
+  // Generate the custom Glib::wrap() function that pre-registers the
+  // wrap_new() function before calling Glib::wrap_auto().
+  std::string returnType = "Glib::RefPtr<" + (std::string) nmspace + "::" + cppTypeName + ">";
+
+  std::cout << "namespace Glib" << std::endl;
+  std::cout << '{' << std::endl << std::endl;
+  std::cout << returnType << " wrap(" << cTypeName << "* object, bool take_copy)" << std::endl;
+  std::cout << '{' << std::endl;
+  std::cout << "  static bool registered_wrap_new = false;" << std::endl;
+  std::cout << "  if(!registered_wrap_new)" << std::endl;
+  std::cout << "  {" << std::endl;
+  std::cout << "    // Call get *_get_type() function which does the registration." << std::endl;
+  std::cout << "    " << getTypeName << "();" << std::endl;
+  std::cout << "    registered_wrap_new = true;" << std::endl;
+  std::cout << "  }" << std::endl;
+  std::cout << std::endl;
+  std::cout << "  return " << returnType << "( dynamic_cast<" << nmspace << "::" << cppTypeName << "*> (Glib::wrap_auto ((GObject*)(object), take_copy)) );" << std::endl;
+  std::cout << '}' << std::endl << std::endl;
+  std::cout << '}' << std::endl;
 }
 
 } // anonymous namespace