engine: command: introduce new type of commands that can be overriden by a mod DLL for better compatibility

engine/common/cmd.c

@@ -518,14 +518,14 @@ static void Cmd_UnAlias_f ( void )
 
 =============================================================================
 */
-typedef struct cmd_s
+struct cmd_s
 {
 	struct cmd_s	*next;
 	char		*name;
 	xcommand_t	function;
 	int		flags;
 	char		*desc;
-} cmd_t;
+};
 
 static int		cmd_argc;
 static const char	*cmd_args = NULL;
@@ -693,11 +693,28 @@ int Cmd_AddCommandEx( const char *cmd_name, xcommand_t function, const char *cmd
 		return 0;
 	}
 
-	// fail if the command already exists
+	// fail if the command already exists and cannot be overriden
-	if( Cmd_Exists( cmd_name ))
+	cmd = Cmd_Exists( cmd_name );
+	if( cmd )
 	{
-		Con_DPrintf( S_ERROR "%s: %s already defined\n", funcname, cmd_name );
+		// some mods register commands that share the name with some engine's commands
-		return 0;
+		// when they aren't critical to keep engine running, we can let mods to override them
+		// unfortunately, we lose original command this way
+		if( FBitSet( cmd->flags, CMD_OVERRIDABLE ))
+		{
+			Mem_Free( cmd->desc );
+			cmd->desc = copystring( cmd_desc );
+			cmd->function = function;
+			cmd->flags = iFlags;
+
+			Con_DPrintf( S_WARN "%s: %s already defined but is allowed to be overriden\n", funcname, cmd_name );
+			return 1;
+		}
+		else
+		{
+			Con_DPrintf( S_ERROR "%s: %s already defined\n", funcname, cmd_name );
+			return 0;
+		}
 	}
 
 	// use a small malloc to avoid zone fragmentation
@@ -789,19 +806,18 @@ void Cmd_LookupCmds( void *buffer, void *ptr, setpair_t callback )
 Cmd_Exists
 ============
 */
-qboolean Cmd_Exists( const char *cmd_name )
+cmd_t *Cmd_Exists( const char *cmd_name )
 {
 #if defined(XASH_HASHED_VARS)
-	return BaseCmd_Find( HM_CMD, cmd_name ) != NULL;
+	return BaseCmd_Find( HM_CMD, cmd_name );
 #else
 	cmd_t	*cmd;
-
 	for( cmd = cmd_functions; cmd; cmd = cmd->next )
 	{
 		if( !Q_strcmp( cmd_name, cmd->name ))
-			return true;
+			return cmd;
 	}
-	return false;
+	return NULL;
 #endif
 }
 

engine/common/common.h

@@ -362,12 +362,13 @@ typedef struct host_parm_s
 
 extern host_parm_t	host;
 
-#define CMD_SERVERDLL	BIT( 0 )		// added by server.dll
+#define CMD_SERVERDLL   BIT( 0 ) // added by server.dll
-#define CMD_CLIENTDLL	BIT( 1 )		// added by client.dll
+#define CMD_CLIENTDLL   BIT( 1 ) // added by client.dll
-#define CMD_GAMEUIDLL	BIT( 2 )		// added by GameUI.dll
+#define CMD_GAMEUIDLL   BIT( 2 ) // added by GameUI.dll
-#define CMD_PRIVILEGED	BIT( 3 )		// only available in privileged mode
+#define CMD_PRIVILEGED  BIT( 3 ) // only available in privileged mode
-#define CMD_FILTERABLE  BIT( 4 )		// filtered in unprivileged mode if cl_filterstuffcmd is 1
+#define CMD_FILTERABLE  BIT( 4 ) // filtered in unprivileged mode if cl_filterstuffcmd is 1
-#define CMD_REFDLL	BIT( 5 )		// added by ref.dll
+#define CMD_REFDLL      BIT( 5 ) // added by ref.dll
+#define CMD_OVERRIDABLE BIT( 6 ) // can be removed by DLLs if name matches
 
 typedef void (*xcommand_t)( void );
 
@@ -418,6 +419,7 @@ byte *FS_LoadDirectFile( const char *path, fs_offset_t *filesizeptr )
 //
 // cmd.c
 //
+typedef struct cmd_s cmd_t;
 void Cbuf_Clear( void );
 void Cbuf_AddText( const char *text );
 void Cbuf_AddTextf( const char *text, ... ) FORMAT_CHECK( 1 );
@@ -431,7 +433,7 @@ const char *Cmd_Args( void ) RETURNS_NONNULL;
 const char *Cmd_Argv( int arg ) RETURNS_NONNULL;
 void Cmd_Init( void );
 void Cmd_Unlink( int group );
-int Cmd_AddCommandEx( const char *cmd_name, xcommand_t function, const char *cmd_desc, int iFlags, const char *funcname );
+int Cmd_AddCommandEx( const char *cmd_name, xcommand_t function, const char *cmd_desc, int flags, const char *funcname );
 
 static inline int Cmd_AddCommand( const char *cmd_name, xcommand_t function, const char *cmd_desc )
 {
@@ -443,13 +445,13 @@ static inline int Cmd_AddRestrictedCommand( const char *cmd_name, xcommand_t fun
 	return Cmd_AddCommandEx( cmd_name, function, cmd_desc, CMD_PRIVILEGED, __func__ );
 }
 
-static inline int Cmd_AddFilteredCommand( const char *cmd_name, xcommand_t function, const char *cmd_desc )
+static inline int Cmd_AddCommandWithFlags( const char *cmd_name, xcommand_t function, const char *cmd_desc, int flags )
 {
-	return Cmd_AddCommandEx( cmd_name, function, cmd_desc, CMD_FILTERABLE, __func__ );
+	return Cmd_AddCommandEx( cmd_name, function, cmd_desc, flags, __func__ );
 }
 
 void Cmd_RemoveCommand( const char *cmd_name );
-qboolean Cmd_Exists( const char *cmd_name );
+cmd_t *Cmd_Exists( const char *cmd_name );
 void Cmd_LookupCmds( void *buffer, void *ptr, setpair_t callback );
 int Cmd_ListMaps( search_t *t , char *lastmapname, size_t len );
 void Cmd_TokenizeString( const char *text );