Move script_run_callbacks to Lua

Author: ShadowNinja

builtin/misc_register.lua

@@ -314,6 +314,45 @@ minetest.register_item(":", {
 	groups = {not_in_creative_inventory=1},
 })
 
+
+function minetest.run_callbacks(callbacks, mode, ...)
+	assert(type(callbacks) == "table")
+	local cb_len = #callbacks
+	if cb_len == 0 then
+		if mode == 2 or mode == 3 then
+			return true
+		elseif mode == 4 or mode == 5 then
+			return false
+		end
+	end
+	local ret = nil
+	for i = 1, cb_len do
+		local cb_ret = callbacks[i](...)
+
+		if mode == 0 and i == 1 then
+			ret = cb_ret
+		elseif mode == 1 and i == cb_len then
+			ret = cb_ret
+		elseif mode == 2 then
+			if not cb_ret or i == 1 then
+				ret = cb_ret
+			end
+		elseif mode == 3 then
+			if cb_ret then
+				return cb_ret
+			end
+			ret = cb_ret
+		elseif mode == 4 then
+			if (cb_ret and not ret) or i == 1 then
+				ret = cb_ret
+			end
+		elseif mode == 5 and cb_ret then
+			return cb_ret
+		end
+	end
+	return ret
+end
+
 --
 -- Callback registration
 --

src/script/common/c_internal.cpp

@@ -66,101 +66,35 @@ void script_error(lua_State *L)
 // Then push nargs arguments.
 // Then call this function, which
 // - runs the callbacks
-// - removes the table and arguments from the lua stack
-// - pushes the return value, computed depending on mode
+// - replaces the table and arguments with the return value,
+//     computed depending on mode
 void script_run_callbacks(lua_State *L, int nargs, RunCallbacksMode mode)
 {
-	// Insert the return value into the lua stack, below the table
 	assert(lua_gettop(L) >= nargs + 1);
 
-	lua_pushnil(L);
-	int rv = lua_gettop(L) - nargs - 1;
-	lua_insert(L, rv);
-
-	// Insert error handler after return value
+	// Insert error handler
 	lua_pushcfunction(L, script_error_handler);
-	int errorhandler = rv + 1;
+	int errorhandler = lua_gettop(L) - nargs - 1;
 	lua_insert(L, errorhandler);
 
-	// Stack now looks like this:
-	// ... <return value = nil> <error handler> <table> <arg#1> <arg#2> ... <arg#n>
-
-	int table = errorhandler + 1;
-	int arg = table + 1;
-
-	luaL_checktype(L, table, LUA_TTABLE);
-
-	// Foreach
-	lua_pushnil(L);
-	bool first_loop = true;
-	while(lua_next(L, table) != 0){
-		// key at index -2 and value at index -1
-		luaL_checktype(L, -1, LUA_TFUNCTION);
-		// Call function
-		for(int i = 0; i < nargs; i++)
-			lua_pushvalue(L, arg+i);
-		if(lua_pcall(L, nargs, 1, errorhandler))
-			script_error(L);
-
-		// Move return value to designated space in stack
-		// Or pop it
-		if(first_loop){
-			// Result of first callback is always moved
-			lua_replace(L, rv);
-			first_loop = false;
-		} else {
-			// Otherwise, what happens depends on the mode
-			if(mode == RUN_CALLBACKS_MODE_FIRST)
-				lua_pop(L, 1);
-			else if(mode == RUN_CALLBACKS_MODE_LAST)
-				lua_replace(L, rv);
-			else if(mode == RUN_CALLBACKS_MODE_AND ||
-					mode == RUN_CALLBACKS_MODE_AND_SC){
-				if((bool)lua_toboolean(L, rv) == true &&
-						(bool)lua_toboolean(L, -1) == false)
-					lua_replace(L, rv);
-				else
-					lua_pop(L, 1);
-			}
-			else if(mode == RUN_CALLBACKS_MODE_OR ||
-					mode == RUN_CALLBACKS_MODE_OR_SC){
-				if((bool)lua_toboolean(L, rv) == false &&
-						(bool)lua_toboolean(L, -1) == true)
-					lua_replace(L, rv);
-				else
-					lua_pop(L, 1);
-			}
-			else
-				assert(0);
-		}
+	// Insert minetest.run_callbacks between error handler and table
+	lua_getglobal(L, "minetest");
+	lua_getfield(L, -1, "run_callbacks");
+	lua_remove(L, -2);
+	lua_insert(L, errorhandler + 1);
 
-		// Handle short circuit modes
-		if(mode == RUN_CALLBACKS_MODE_AND_SC &&
-				(bool)lua_toboolean(L, rv) == false)
-			break;
-		else if(mode == RUN_CALLBACKS_MODE_OR_SC &&
-				(bool)lua_toboolean(L, rv) == true)
-			break;
+	// Insert mode after table
+	lua_pushnumber(L, (int) mode);
+	lua_insert(L, errorhandler + 3);
 
-		// value removed, keep key for next iteration
-	}
-
-	// Remove stuff from stack, leaving only the return value
-	lua_settop(L, rv);
+	// Stack now looks like this:
+	// ... <error handler> <run_callbacks> <table> <mode> <arg#1> <arg#2> ... <arg#n>
 
-	// Fix return value in case no callbacks were called
-	if(first_loop){
-		if(mode == RUN_CALLBACKS_MODE_AND ||
-				mode == RUN_CALLBACKS_MODE_AND_SC){
-			lua_pop(L, 1);
-			lua_pushboolean(L, true);
-		}
-		else if(mode == RUN_CALLBACKS_MODE_OR ||
-				mode == RUN_CALLBACKS_MODE_OR_SC){
-			lua_pop(L, 1);
-			lua_pushboolean(L, false);
-		}
+	if (lua_pcall(L, nargs + 2, 1, errorhandler)) {
+		script_error(L);
 	}
+
+	lua_remove(L, -2); // Remove error handler
 }