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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
/*
* This code is based on Broken Sword 2.5 engine
*
* Copyright (c) Malte Thiesen, Daniel Queteschiner and Michael Elsdoerfer
*
* Licensed under GNU GPL v2
*
*/
#include "common/textconsole.h"
#include "sword25/script/luacallback.h"
#include "sword25/script/luabindhelper.h"
#include "sword25/util/lua/lua.h"
#include "sword25/util/lua/lauxlib.h"
const char *CALLBACKTABLE_NAME = "__CALLBACKS";
namespace Sword25 {
LuaCallback::LuaCallback(lua_State *L) {
// Create callback table
lua_newtable(L);
lua_setglobal(L, CALLBACKTABLE_NAME);
}
LuaCallback::~LuaCallback() {
}
void LuaCallback::registerCallbackFunction(lua_State *L, uint objectHandle) {
assert(lua_isfunction(L, -1));
ensureObjectCallbackTableExists(L, objectHandle);
// Store function in the callback object table store
lua_pushvalue(L, -2);
luaL_ref(L, -2);
// Pop the function and object callback table from the stack
lua_pop(L, 2);
}
void LuaCallback::unregisterCallbackFunction(lua_State *L, uint objectHandle) {
assert(lua_isfunction(L, -1));
ensureObjectCallbackTableExists(L, objectHandle);
// Iterate over all elements of the object callback table and remove the function from it
lua_pushnil(L);
while (lua_next(L, -2) != 0) {
// The value of the current element is the top of the stack, including the index
// If the value is identical to the function parameters, it is removed from the table
if (lua_equal(L, -1, -4)) {
lua_pushvalue(L, -2);
lua_pushnil(L);
lua_settable(L, -5);
// The function was found, iteration can be stopped
lua_pop(L, 2);
break;
} else {
// Pop value from the stack. The index is then ready for the next call to lua_next()
lua_pop(L, 1);
}
}
// Function and object table are popped from the stack
lua_pop(L, 2);
}
void LuaCallback::removeAllObjectCallbacks(lua_State *L, uint objectHandle) {
pushCallbackTable(L);
// Remove the object callback from the callback table
lua_pushnumber(L, objectHandle);
lua_pushnil(L);
lua_settable(L, -3);
lua_pop(L, 1);
}
void LuaCallback::invokeCallbackFunctions(lua_State *L, uint objectHandle) {
ensureObjectCallbackTableExists(L, objectHandle);
// Iterate through the table and perform all the callbacks
lua_pushnil(L);
while (lua_next(L, -2) != 0) {
// The value of the current element is at the top of the stack, including the index
// If the value is a function, execute it
if (lua_type(L, -1) == LUA_TFUNCTION) {
// Pre-Function Call
// Derived classes can function in this parameter onto the stack.
// The return value indicates the number of parameters
int argumentCount = preFunctionInvokation(L);
// Lua_pcall the function and the parameters pop themselves from the stack
if (lua_pcall(L, argumentCount, 0, 0) != 0) {
// An error has occurred
error("An error occured executing a callback function: %s", lua_tostring(L, -1));
// Pop error message from the stack
lua_pop(L, 1);
}
} else {
// Pop value from the stack. The index is then ready for the next call to lua_next()
lua_pop(L, 1);
}
}
}
void LuaCallback::ensureObjectCallbackTableExists(lua_State *L, uint objectHandle) {
pushObjectCallbackTable(L, objectHandle);
// If the table is nil, it must first be created
if (lua_isnil(L, -1)) {
// Pop nil from stack
lua_pop(L, 1);
pushCallbackTable(L);
// Create the table, and put the objectHandle into it
lua_newtable(L);
lua_pushnumber(L, objectHandle);
lua_pushvalue(L, -2);
lua_settable(L, -4);
// Pop the callback table from the stack
lua_remove(L, -2);
}
}
void LuaCallback::pushCallbackTable(lua_State *L) {
lua_getglobal(L, CALLBACKTABLE_NAME);
}
void LuaCallback::pushObjectCallbackTable(lua_State *L, uint objectHandle) {
pushCallbackTable(L);
// Push Object Callback table onto the stack
lua_pushnumber(L, objectHandle);
lua_gettable(L, -2);
// Pop the callback table from the stack
lua_remove(L, -2);
}
} // End of namespace Sword25
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