Re #374 (Move module system to a modern C++-styled implementation) Made GfModule::unload a static function for symmetry and fix of a crash

git-svn-id: https://svn.code.sf.net/p/speed-dreams/code/trunk@3460 30fe4595-0a0c-4342-8851-515496e4dcbd

Former-commit-id: d6d0ea2ee387f401dc5ac97c452d92fdc815cb8f
Former-commit-id: cf6f5d1028a59f6c043761da97fadcc5a5d6beba

src/libs/tgf/module.cpp

@@ -137,66 +137,88 @@ GfModule* GfModule::load(const std::string& strShLibName)
 	return _mapModulesByLibName[strShLibName];
 }
 
-bool GfModule::unload()
+bool GfModule::unload(GfModule*& pModule)
 {
-	if (_mapModulesByLibName.find(_strShLibName) == _mapModulesByLibName.end())
-	{
-		GfLogError("Can't unload not yet loaded module %s\n", _strShLibName.c_str());
-		return false;
-	}
-
 	// Try and get the module closing function.
-	tModCloseFunc modCloseFunc = (tModCloseFunc)dlsym(_hShLibHandle, pszCloseModuleFuncName);
+	std::string strShLibName = pModule->getSharedLibName();
+	void* hShLibHandle = pModule->getSharedLibHandle();
+	tModCloseFunc modCloseFunc = (tModCloseFunc)dlsym(hShLibHandle, pszCloseModuleFuncName);
     if (!modCloseFunc)
     {
 		GfLogWarning("Library %s doesn't export any '%s' function' ; not called\n",
-					 _strShLibName.c_str(), pszCloseModuleFuncName);
+					 strShLibName.c_str(), pszCloseModuleFuncName);
 	}
 
 	// Call the module closing function (must delete the module instance).
 	if (modCloseFunc())
 	{
 		GfLogWarning("Library %s '%s' function call failed ; going on\n",
-					 _strShLibName.c_str(), pszCloseModuleFuncName);
+					 strShLibName.c_str(), pszCloseModuleFuncName);
 	}
-
-	// Unregister the module.
-	_mapModulesByLibName.erase(_strShLibName);
+	
+	// Make it clear that the passed pointer is no more usable (it was deleted).
+	pModule = 0; 
 	
 	// Try and close the shared library.
-	if (dlclose(_hShLibHandle))
+	if (dlclose(hShLibHandle))
 	{
 		GfLogWarning("Failed to unload library %s (%s) ; \n",
-					 _strShLibName.c_str(), lastDLErrorString().c_str());
+					 strShLibName.c_str(), lastDLErrorString().c_str());
 		return false;
 	}
 	
-	GfLogTrace("Module %s unloaded\n", _strShLibName.c_str());
+	GfLogTrace("Module %s unloaded\n", strShLibName.c_str());
 
 	return true;
 }
 
-bool GfModule::register_(GfModule* pModule)
+bool GfModule::register_(GfModule* pModule) // Can't use 'register' as it is a C++ keyword.
 {
-	bool status = false;
+	bool bStatus = false;
 	
 	if (pModule)
 	{
 		if (_mapModulesByLibName.find(pModule->getSharedLibName()) != _mapModulesByLibName.end())
 		{
-			GfLogError("Can't register another module in %s\n", pModule->getSharedLibName().c_str());
+			GfLogError("Can only register 1 module from %s\n", pModule->getSharedLibName().c_str());
 		}
 		else
 		{
 			_mapModulesByLibName[pModule->getSharedLibName()] = pModule;
-			status = true;
+			bStatus = true;
 		}
 	}
 
-	return status;
+	return bStatus;
+}
+
+bool GfModule::unregister(GfModule* pModule)
+{
+	bool bStatus = false;
+	
+	if (pModule)
+	{
+		if (_mapModulesByLibName.find(pModule->getSharedLibName()) == _mapModulesByLibName.end())
+		{
+			GfLogError("Can't unregister module in %s (not yet registered)\n", 
+					   pModule->getSharedLibName().c_str());
+		}
+		else
+		{
+			_mapModulesByLibName.erase(pModule->getSharedLibName());
+			bStatus = true;
+		}
+	}
+
+	return bStatus;
 }
 
 const std::string& GfModule::getSharedLibName() const
 {
 	return _strShLibName;
 }
+
+void* GfModule::getSharedLibHandle() const
+{
+	return _hShLibHandle;
+}

src/libs/tgf/tgf.hpp

@@ -24,10 +24,10 @@
 #ifndef __TGF__HPP__
 #define __TGF__HPP__
 
-#ifdef _MSC_VER
-// Disable useless MSVC warnings
-#  pragma warning (disable:4251) // class XXX needs a DLL interface ...
-#endif
+#ifdef _MSC_VER
+// Disable useless MSVC warnings
+#  pragma warning (disable:4251) // class XXX needs a DLL interface ...
+#endif
 
 #include <string>
 #include <map>
@@ -36,11 +36,17 @@
 
 
 //****************************************
-// New dynamicaly loadable modules system
-// * 1 module per shared library
-// * the shared library exports 2 extern "C" functions :
-//   - bool initializeModule(); // TODO: find a different name (legacy welcome modules)
-//   - bool terminateModule(); // Idem
+// New dynamically loadable modules system
+// - 1 and only 1 module per shared library,
+// - a module is a GfModule-derived class instance (and even a singleton),
+// - the shared library exports 2 extern 'C' functions :
+//   - int openGfModule(const char* pszShLibName, void* hShLibHandle) :
+//     it must instanciate the module class (new), register the module instance (register_),
+//     initialize / allocate any needed internal resource and finally return 0
+//     if everything is OK, non-0 otherwise;
+//   - int closeGfModule() :
+//     it must release any allocated resource, unregister the module instance (unregister),
+//     and finally return 0, non-0 otherwise.
 
 class TGF_API GfModule
 {
@@ -49,8 +55,8 @@ class TGF_API GfModule
 	//! Load a module from the given module library file.
 	static GfModule* load(const std::string& strShLibName);
 
-	//! Unload a module and the associated library (supposed to contain no other module).
-	virtual bool unload();
+	//! Delete a module and unload the associated library (supposed to contain no other module).
+	static bool unload(GfModule*& pModule);
 
 	//! Get the module as a pointer to the given interface (aka "facet").
 	template <class Interface>
@@ -73,6 +79,14 @@ class TGF_API GfModule
 	//! Get the asssociated shared library path-name.
 	const std::string& getSharedLibName() const;
 		
+	//! Get the asssociated shared library handle.
+	void* getSharedLibHandle() const;
+		
+ protected:
+
+	//! Unregister a module instance.
+	static bool unregister(GfModule* pModule);
+	
  protected:
 
 	//! The table of loaded modules and their associated shared library (key = file name).