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Diffstat (limited to 'engines/sword25/script/luacallback.cpp')
| -rw-r--r-- | engines/sword25/script/luacallback.cpp | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/engines/sword25/script/luacallback.cpp b/engines/sword25/script/luacallback.cpp new file mode 100644 index 0000000000..6d2e634632 --- /dev/null +++ b/engines/sword25/script/luacallback.cpp @@ -0,0 +1,180 @@ +/* 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. + * + * $URL$ + * $Id$ + * + */ + +/* + * 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 "sword25/script/luacallback.h" +#include "sword25/script/luabindhelper.h" + +namespace Lua { + +extern "C" +{ +#include "sword25/util/lua/lua.h" +#include "sword25/util/lua/lauxlib.h" +} + +const char *CALLBACKTABLE_NAME = "__CALLBACKS"; + +} + +namespace Sword25 { + +#define BS_LOG_PREFIX "LUA" + +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) { + BS_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) { + BS_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 + BS_LOG_ERRORLN("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 |