Fix remaining memory leaks caused by API misuse

client/CServerHandler.cpp

@@ -57,6 +57,7 @@
 #include "LobbyClientNetPackVisitors.h"
 
 #include <vcmi/events/EventBus.h>
+#include <SDL_thread.h>
 
 #include <boost/lexical_cast.hpp>
 
@@ -114,9 +115,13 @@ void CServerHandler::threadRunNetwork()
 	}
 	catch (const TerminationRequestedException &)
 	{
+		// VCMI can run SDL methods on network thread, leading to usage of thread-local storage by SDL
+		// Such storage needs to be cleaned up manually for threads that were not created by SDL
+		SDL_TLSCleanup();
 		logGlobal->info("Terminating network thread");
 		return;
 	}
+	SDL_TLSCleanup();
 	logGlobal->info("Ending network thread");
 }
 

client/eventsSDL/InputHandler.cpp

@@ -410,7 +410,7 @@ void InputHandler::dispatchMainThread(const std::function<void()> & functor)
 	SDL_Event event;
 	event.user.type = SDL_USEREVENT;
 	event.user.code = 0;
-	event.user.data1 = static_cast <void*>(heapFunctor.get());
+	event.user.data1 = nullptr;
 	event.user.data2 = nullptr;
 	SDL_PushEvent(&event);
 
@@ -426,9 +426,6 @@ void InputHandler::handleUserEvent(const SDL_UserEvent & current)
 	if (!dispatchedTasks.try_pop(task))
 		throw std::runtime_error("InputHandler::handleUserEvent received without active task!");
 
-	if (current.data1 != task.get())
-		throw std::runtime_error("InputHandler::handleUserEvent received unknown pointer!");
-
 	(*task)();
 }
 

client/media/CVideoHandler.cpp

@@ -373,6 +373,11 @@ FFMpegStream::~FFMpegStream()
 	avcodec_free_context(&codecContext);
 
 	avformat_close_input(&formatContext);
+
+	// for some reason, buffer is managed (e.g. reallocated) by FFmpeg
+	// however, it must still be freed manually by user
+	if (context->buffer)
+		av_free(context->buffer);
 	av_free(context);
 }
 

client/renderSDL/SDLImage.cpp

@@ -448,5 +448,6 @@ void SDLImageShared::savePalette()
 SDLImageShared::~SDLImageShared()
 {
 	SDL_FreeSurface(surf);
-	SDL_FreePalette(originalPalette);
+	if (originalPalette)
+		SDL_FreePalette(originalPalette);
 }

client/renderSDL/SDLImageScaler.cpp

@@ -236,8 +236,8 @@ SDLImageScaler::~SDLImageScaler()
 {
 	ENGINE->dispatchMainThread([surface = intermediate]()
 	{
-		// potentially SDL bug, execute SDL_FreeSurface in main thread to avoid thread races to its internal state
+		// SDL_FreeSurface must be executed in main thread to avoid thread races to its internal state
-		// may be fixed somewhere between 2.26.5 - 2.30
+		// will be no longer necessary in SDL 3
 		SDL_FreeSurface(surface);
 	});
 }

client/renderSDL/ScalableImage.cpp

@@ -90,7 +90,8 @@ ScalableImageParameters::ScalableImageParameters(const SDL_Palette * originalPal
 
 ScalableImageParameters::~ScalableImageParameters()
 {
-	SDL_FreePalette(palette);
+	if (palette)
+		SDL_FreePalette(palette);
 }
 
 void ScalableImageParameters::preparePalette(const SDL_Palette * originalPalette, EImageBlitMode blitMode)