engine: add a function to determine if library has direct dependency on chosen DLL(Win32 only)

engine/common/library.h

@@ -42,6 +42,7 @@ void *COM_FunctionFromName_SR( void *hInstance, const char *pName ); // Save/Res
 void *COM_FunctionFromName( void *hInstance, const char *pName );
 void COM_FreeLibrary( void *hInstance );
 const char *COM_GetLibraryError( void );
+qboolean COM_CheckLibraryDirectDependency( const char *name, const char *depname, qboolean directpath );
 
 // TODO: Move to internal?
 void COM_ResetLibraryError( void );

engine/platform/posix/lib_posix.c

@@ -58,6 +58,12 @@ int dladdr( const void *addr, Dl_info *info )
 }
 #endif // XASH_NO_LIBDL
 
+qboolean COM_CheckLibraryDirectDependency( const char *name, const char *depname, qboolean directpath )
+{
+	// TODO: implement
+	return true;
+}
+
 void *COM_LoadLibrary( const char *dllname, int build_ordinals_table, qboolean directpath )
 {
 	dll_user_t *hInst = NULL;

engine/platform/win32/lib_win.c

@@ -951,6 +951,72 @@ table_error:
 	return false;
 }
 
+qboolean COM_CheckLibraryDirectDependency( const char *name, const char *depname, qboolean directpath )
+{
+	MEMORYMODULE	*result = NULL;
+	PIMAGE_DOS_HEADER	dos_header;
+	PIMAGE_NT_HEADERS	old_header;
+	PIMAGE_DATA_DIRECTORY	directory;
+	PIMAGE_IMPORT_DESCRIPTOR importDesc;
+	string errorstring;
+	void		*data = NULL;
+	dll_user_t *hInst;
+
+	hInst = FS_FindLibrary( name, directpath );
+	if( !hInst )
+	{
+		return false; // nothing to load
+	}
+
+	data = FS_LoadFile( name, NULL, false );
+	if( !data )
+	{
+		Q_snprintf( errorstring, sizeof( errorstring ), "couldn't load %s", name );
+		return false;
+	}
+
+	dos_header = ( PIMAGE_DOS_HEADER )data;
+	if( dos_header->e_magic != IMAGE_DOS_SIGNATURE )
+	{
+		Q_snprintf( errorstring, sizeof( errorstring ), "%s it's not a valid executable file", name );
+		goto libraryerror;
+	}
+
+	old_header = ( PIMAGE_NT_HEADERS )&( ( const byte * )( data ) )[dos_header->e_lfanew];
+	if( old_header->Signature != IMAGE_NT_SIGNATURE )
+	{
+		Q_snprintf( errorstring, sizeof( errorstring ), "%s missing PE header", name );
+		goto libraryerror;
+	}
+
+	directory = &old_header->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT];
+	
+	if( directory->Size <= 0 )
+	{
+		Q_snprintf( errorstring, sizeof( errorstring ), "%s has no dependencies. Is this dll valid?\n" );
+		goto libraryerror;
+	}
+
+	importDesc = (PIMAGE_IMPORT_DESCRIPTOR)CALCULATE_ADDRESS( data, directory->VirtualAddress );
+
+	for( ; importDesc->Name; importDesc++ )
+	{
+		const char *importName = ( const char* )CALCULATE_ADDRESS( data, importDesc->Name );
+		Con_Reportf( "library %s has direct dependency %s\n", name, importName );
+
+		if( !Q_stricmp( importName, depname ) )
+		{
+			Mem_Free( data );
+			return true;
+		}
+	}
+
+libraryerror:
+	Con_Printf( errorstring );
+	Mem_Free( data ); // release memory
+	return false;
+}
+
 /*
 ================
 COM_LoadLibrary
@@ -967,7 +1033,7 @@ void *COM_LoadLibrary( const char *dllname, int build_ordinals_table, qboolean d
 
 	if( hInst->custom_loader )
 	{
-          	if( hInst->encrypted )
+		if( hInst->encrypted )
 		{
 			Con_Printf( S_ERROR "LoadLibrary: couldn't load encrypted library %s\n", dllname );
 			return NULL;