830 lines
21 KiB
C++
830 lines
21 KiB
C++
//------------------------------------------------------------------------------
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/*
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https://github.com/vinniefalco/LuaBridge
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Copyright 2019, Dmitry Tarakanov
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Copyright 2012, Vinnie Falco <vinnie.falco@gmail.com>
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License: The MIT License (http://www.opensource.org/licenses/mit-license.php)
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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//==============================================================================
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#pragma once
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#include <LuaBridge/detail/ClassInfo.h>
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#include <cassert>
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#include <stdexcept>
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namespace luabridge {
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//==============================================================================
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/**
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Return the identity pointer for our lightuserdata tokens.
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Because of Lua's dynamic typing and our improvised system of imposing C++
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class structure, there is the possibility that executing scripts may
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knowingly or unknowingly cause invalid data to get passed to the C functions
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created by LuaBridge. In particular, our security model addresses the
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following:
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1. Scripts cannot create a userdata (ignoring the debug lib).
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2. Scripts cannot create a lightuserdata (ignoring the debug lib).
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3. Scripts cannot set the metatable on a userdata.
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*/
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/**
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Interface to a class pointer retrievable from a userdata.
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*/
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class Userdata
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{
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protected:
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void* m_p; // subclasses must set this
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Userdata() : m_p (0)
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{
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}
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//--------------------------------------------------------------------------
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/**
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Get an untyped pointer to the contained class.
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*/
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void* getPointer ()
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{
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return m_p;
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}
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private:
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//--------------------------------------------------------------------------
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/**
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Validate and retrieve a Userdata on the stack.
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The Userdata must exactly match the corresponding class table or
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const table, or else a Lua error is raised. This is used for the
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__gc metamethod.
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*/
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static Userdata* getExactClass (lua_State* L, int index, void const* /*classKey*/)
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{
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return static_cast <Userdata*> (lua_touserdata (L, lua_absindex (L, index)));
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}
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//--------------------------------------------------------------------------
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/**
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Validate and retrieve a Userdata on the stack.
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The Userdata must be derived from or the same as the given base class,
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identified by the key. If canBeConst is false, generates an error if
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the resulting Userdata represents to a const object. We do the type check
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first so that the error message is informative.
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*/
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static Userdata* getClass (lua_State* L,
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int index,
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void const* registryConstKey,
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void const* registryClassKey,
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bool canBeConst)
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{
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index = lua_absindex (L, index);
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lua_getmetatable (L, index); // Stack: object metatable (ot) | nil
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if (!lua_istable (L, -1))
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{
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lua_rawgetp (L, LUA_REGISTRYINDEX, registryClassKey); // Stack: registry metatable (rt) | nil
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return throwBadArg (L, index);
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}
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lua_rawgetp (L, -1, getConstKey ()); // Stack: ot | nil, const table (co) | nil
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assert (lua_istable (L, -1) || lua_isnil (L, -1));
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// If const table is NOT present, object is const. Use non-const registry table
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// if object cannot be const, so constness validation is done automatically.
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// E.g. nonConstFn (constObj)
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// -> canBeConst = false, isConst = true
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// -> 'Class' registry table, 'const Class' object table
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// -> 'expected Class, got const Class'
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bool isConst = lua_isnil (L, -1); // Stack: ot | nil, nil, rt
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if (isConst && canBeConst)
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{
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lua_rawgetp (L, LUA_REGISTRYINDEX, registryConstKey); // Stack: ot, nil, rt
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}
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else
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{
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lua_rawgetp (L, LUA_REGISTRYINDEX, registryClassKey); // Stack: ot, co, rt
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}
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lua_insert (L, -3); // Stack: rt, ot, co | nil
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lua_pop (L, 1); // Stack: rt, ot
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for (;;)
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{
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if (lua_rawequal (L, -1, -2)) // Stack: rt, ot
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{
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lua_pop (L, 2); // Stack: -
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return static_cast <Userdata*> (lua_touserdata (L, index));
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}
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// Replace current metatable with it's base class.
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lua_rawgetp (L, -1, getParentKey ()); // Stack: rt, ot, parent ot (pot) | nil
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if (lua_isnil (L, -1)) // Stack: rt, ot, nil
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{
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// Drop the object metatable because it may be some parent metatable
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lua_pop (L, 2); // Stack: rt
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return throwBadArg (L, index);
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}
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lua_remove (L, -2); // Stack: rt, pot
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}
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// no return
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}
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static bool isInstance (lua_State* L, int index, void const* registryClassKey)
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{
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index = lua_absindex (L, index);
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int result = lua_getmetatable (L, index); // Stack: object metatable (ot) | nothing
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if (result == 0)
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{
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return false; // Nothing was pushed on the stack
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}
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if (!lua_istable (L, -1))
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{
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lua_pop (L, 1); // Stack: -
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return false;
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}
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lua_rawgetp (L, LUA_REGISTRYINDEX, registryClassKey); // Stack: ot, rt
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lua_insert (L, -2); // Stack: rt, ot
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for (;;)
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{
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if (lua_rawequal (L, -1, -2)) // Stack: rt, ot
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{
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lua_pop (L, 2); // Stack: -
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return true;
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}
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// Replace current metatable with it's base class.
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lua_rawgetp (L, -1, getParentKey ()); // Stack: rt, ot, parent ot (pot) | nil
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if (lua_isnil (L, -1)) // Stack: rt, ot, nil
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{
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lua_pop (L, 3); // Stack: -
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return false;
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}
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lua_remove (L, -2); // Stack: rt, pot
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}
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}
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static Userdata* throwBadArg (lua_State* L, int index)
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{
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assert (lua_istable (L, -1) || lua_isnil (L, -1)); // Stack: rt | nil
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const char* expected = 0;
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if (lua_isnil (L, -1)) // Stack: nil
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{
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expected = "unregistered class";
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}
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else
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{
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lua_rawgetp (L, -1, getTypeKey ()); // Stack: rt, registry type
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expected = lua_tostring (L, -1);
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}
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const char* got = 0;
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if (lua_isuserdata (L, index))
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{
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lua_getmetatable (L, index); // Stack: ..., ot | nil
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if (lua_istable (L, -1)) // Stack: ..., ot
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{
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lua_rawgetp (L, -1, getTypeKey ()); // Stack: ..., ot, object type | nil
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if (lua_isstring (L, -1))
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{
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got = lua_tostring (L, -1);
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}
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}
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}
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if (!got)
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{
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got = lua_typename (L, lua_type (L, index));
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}
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luaL_argerror (L, index, lua_pushfstring (L, "%s expected, got %s", expected, got));
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return 0;
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}
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public:
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virtual ~Userdata () { }
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//--------------------------------------------------------------------------
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/**
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Returns the Userdata* if the class on the Lua stack matches.
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If the class does not match, a Lua error is raised.
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*/
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template <class T>
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static Userdata* getExact (lua_State* L, int index)
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{
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return getExactClass (L, index, ClassInfo <T>::getClassKey ());
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}
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//--------------------------------------------------------------------------
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/**
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Get a pointer to the class from the Lua stack.
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If the object is not the class or a subclass, or it violates the
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const-ness, a Lua error is raised.
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*/
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template <class T>
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static T* get (lua_State* L, int index, bool canBeConst)
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{
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if (lua_isnil (L, index))
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return 0;
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return static_cast <T*> (getClass (
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L, index, ClassInfo <T>::getConstKey (),
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ClassInfo <T>::getClassKey (),
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canBeConst)->getPointer ());
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}
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template <class T>
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static bool isInstance (lua_State* L, int index)
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{
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return isInstance (L, index, ClassInfo <T>::getClassKey ());
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}
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};
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//----------------------------------------------------------------------------
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/**
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Wraps a class object stored in a Lua userdata.
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The lifetime of the object is managed by Lua. The object is constructed
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inside the userdata using placement new.
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*/
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template <class T>
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class UserdataValue : public Userdata
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{
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private:
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UserdataValue <T> (UserdataValue <T> const&);
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UserdataValue <T> operator= (UserdataValue <T> const&);
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char m_storage [sizeof (T)];
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private:
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/**
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Used for placement construction.
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*/
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UserdataValue ()
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{
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m_p = 0;
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}
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~UserdataValue ()
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{
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if (getPointer () != 0)
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{
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getObject ()->~T ();
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}
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}
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public:
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/**
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Push a T via placement new.
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The caller is responsible for calling placement new using the
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returned uninitialized storage.
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*/
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static UserdataValue <T>* place (lua_State* const L)
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{
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UserdataValue <T>* const ud = new (
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lua_newuserdata (L, sizeof (UserdataValue <T>))) UserdataValue <T> ();
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lua_rawgetp (L, LUA_REGISTRYINDEX, ClassInfo <T>::getClassKey ());
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if (!lua_istable (L, -1))
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{
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throw std::logic_error ("The class is not registered in LuaBridge");
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}
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lua_setmetatable (L, -2);
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return ud;
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}
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/**
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Push T via copy construction from U.
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*/
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template <class U>
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static inline void push (lua_State* const L, U const& u)
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{
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UserdataValue <T>* ud = place (L);
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new (ud->getObject ()) U (u);
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ud->commit ();
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}
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/**
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Confirm object construction.
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*/
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void commit ()
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{
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m_p = getObject ();
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}
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T* getObject ()
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{
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// If this fails to compile it means you forgot to provide
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// a Container specialization for your container!
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//
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return reinterpret_cast <T*> (&m_storage [0]);
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}
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};
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//----------------------------------------------------------------------------
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/**
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Wraps a pointer to a class object inside a Lua userdata.
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The lifetime of the object is managed by C++.
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*/
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class UserdataPtr : public Userdata
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{
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private:
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UserdataPtr (UserdataPtr const&);
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UserdataPtr operator= (UserdataPtr const&);
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private:
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/** Push a pointer to object using metatable key.
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*/
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static void push (lua_State* L, const void* p, void const* const key)
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{
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new (lua_newuserdata (L, sizeof (UserdataPtr))) UserdataPtr (const_cast <void*> (p));
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lua_rawgetp (L, LUA_REGISTRYINDEX, key);
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if (!lua_istable (L, -1))
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{
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throw std::logic_error ("The class is not registered in LuaBridge");
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}
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lua_setmetatable (L, -2);
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}
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explicit UserdataPtr (void* const p)
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{
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m_p = p;
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// Can't construct with a null pointer!
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//
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assert (m_p != 0);
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}
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public:
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/** Push non-const pointer to object.
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*/
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template <class T>
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static void push (lua_State* const L, T* const p)
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{
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if (p)
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push (L, p, ClassInfo <T>::getClassKey ());
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else
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lua_pushnil (L);
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}
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/** Push const pointer to object.
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*/
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template <class T>
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static void push (lua_State* const L, T const* const p)
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{
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if (p)
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push (L, p, ClassInfo <T>::getConstKey ());
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else
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lua_pushnil (L);
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}
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};
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//============================================================================
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/**
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Wraps a container that references a class object.
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The template argument C is the container type, ContainerTraits must be
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specialized on C or else a compile error will result.
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*/
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template <class C>
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class UserdataShared : public Userdata
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{
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private:
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UserdataShared (UserdataShared <C> const&);
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UserdataShared <C>& operator= (UserdataShared <C> const&);
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typedef typename TypeTraits::removeConst <
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typename ContainerTraits <C>::Type>::Type T;
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C m_c;
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private:
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~UserdataShared ()
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{
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}
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public:
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/**
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Construct from a container to the class or a derived class.
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*/
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template <class U>
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explicit UserdataShared (U const& u) : m_c (u)
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{
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m_p = const_cast <void*> (reinterpret_cast <void const*> (
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(ContainerTraits <C>::get (m_c))));
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}
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/**
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Construct from a pointer to the class or a derived class.
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*/
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template <class U>
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explicit UserdataShared (U* u) : m_c (u)
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{
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m_p = const_cast <void*> (reinterpret_cast <void const*> (
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(ContainerTraits <C>::get (m_c))));
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}
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};
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//----------------------------------------------------------------------------
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//
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// SFINAE helpers.
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//
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// non-const objects
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template <class C, bool makeObjectConst>
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struct UserdataSharedHelper
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{
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typedef typename TypeTraits::removeConst <
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typename ContainerTraits <C>::Type>::Type T;
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static void push (lua_State* L, C const& c)
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{
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if (ContainerTraits <C>::get (c) != 0)
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{
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new (lua_newuserdata (L, sizeof (UserdataShared <C>))) UserdataShared <C> (c);
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lua_rawgetp (L, LUA_REGISTRYINDEX, ClassInfo <T>::getClassKey ());
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// If this goes off it means the class T is unregistered!
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assert (lua_istable (L, -1));
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lua_setmetatable (L, -2);
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}
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else
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{
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lua_pushnil (L);
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}
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}
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static void push (lua_State* L, T* const t)
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{
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if (t)
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{
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new (lua_newuserdata (L, sizeof (UserdataShared <C>))) UserdataShared <C> (t);
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lua_rawgetp (L, LUA_REGISTRYINDEX, ClassInfo <T>::getClassKey ());
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// If this goes off it means the class T is unregistered!
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assert (lua_istable (L, -1));
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lua_setmetatable (L, -2);
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}
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else
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{
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lua_pushnil (L);
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}
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}
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};
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// const objects
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template <class C>
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struct UserdataSharedHelper <C, true>
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{
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typedef typename TypeTraits::removeConst <
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typename ContainerTraits <C>::Type>::Type T;
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static void push (lua_State* L, C const& c)
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{
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if (ContainerTraits <C>::get (c) != 0)
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{
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new (lua_newuserdata (L, sizeof (UserdataShared <C>))) UserdataShared <C> (c);
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lua_rawgetp (L, LUA_REGISTRYINDEX, ClassInfo <T>::getConstKey ());
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// If this goes off it means the class T is unregistered!
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assert (lua_istable (L, -1));
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lua_setmetatable (L, -2);
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}
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else
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{
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lua_pushnil (L);
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}
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}
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static void push (lua_State* L, T* const t)
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{
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if (t)
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{
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new (lua_newuserdata (L, sizeof (UserdataShared <C>))) UserdataShared <C> (t);
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lua_rawgetp (L, LUA_REGISTRYINDEX, ClassInfo <T>::getConstKey ());
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// If this goes off it means the class T is unregistered!
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assert (lua_istable (L, -1));
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lua_setmetatable (L, -2);
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}
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else
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{
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lua_pushnil (L);
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}
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}
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};
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/**
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Pass by container.
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The container controls the object lifetime. Typically this will be a
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lifetime shared by C++ and Lua using a reference count. Because of type
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erasure, containers like std::shared_ptr will not work. Containers must
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either be of the intrusive variety, or in the style of the RefCountedPtr
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type provided by LuaBridge (that uses a global hash table).
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*/
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template <class C, bool byContainer>
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struct StackHelper
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{
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static void push (lua_State* L, C const& c)
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{
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UserdataSharedHelper <C,
|
|
TypeTraits::isConst <typename ContainerTraits <C>::Type>::value>::push (L, c);
|
|
}
|
|
|
|
typedef typename TypeTraits::removeConst <
|
|
typename ContainerTraits <C>::Type>::Type T;
|
|
|
|
static C get (lua_State* L, int index)
|
|
{
|
|
return Userdata::get <T> (L, index, true);
|
|
}
|
|
};
|
|
|
|
/**
|
|
Pass by value.
|
|
|
|
Lifetime is managed by Lua. A C++ function which accesses a pointer or
|
|
reference to an object outside the activation record in which it was
|
|
retrieved may result in undefined behavior if Lua garbage collected it.
|
|
*/
|
|
template <class T>
|
|
struct StackHelper <T, false>
|
|
{
|
|
static inline void push (lua_State* L, T const& t)
|
|
{
|
|
UserdataValue <T>::push (L, t);
|
|
}
|
|
|
|
static inline T const& get (lua_State* L, int index)
|
|
{
|
|
return *Userdata::get <T> (L, index, true);
|
|
}
|
|
};
|
|
|
|
|
|
//------------------------------------------------------------------------------
|
|
/**
|
|
Lua stack conversions for pointers and references to class objects.
|
|
|
|
Lifetime is managed by C++. Lua code which remembers a reference to the
|
|
value may result in undefined behavior if C++ destroys the object. The
|
|
handling of the const and volatile qualifiers happens in UserdataPtr.
|
|
*/
|
|
|
|
template <class C, bool byContainer>
|
|
struct RefStackHelper
|
|
{
|
|
typedef C return_type;
|
|
|
|
static inline void push (lua_State* L, C const& t)
|
|
{
|
|
UserdataSharedHelper <C,
|
|
TypeTraits::isConst <typename ContainerTraits <C>::Type>::value>::push (L, t);
|
|
}
|
|
|
|
typedef typename TypeTraits::removeConst <
|
|
typename ContainerTraits <C>::Type>::Type T;
|
|
|
|
static return_type get (lua_State* L, int index)
|
|
{
|
|
return Userdata::get <T> (L, index, true);
|
|
}
|
|
};
|
|
|
|
template <class T>
|
|
struct RefStackHelper <T, false>
|
|
{
|
|
typedef T& return_type;
|
|
|
|
static void push (lua_State* L, T const& t)
|
|
{
|
|
UserdataPtr::push (L, &t);
|
|
}
|
|
|
|
static return_type get (lua_State* L, int index)
|
|
{
|
|
T* t = Userdata::get <T> (L, index, true);
|
|
|
|
if (!t)
|
|
luaL_error (L, "nil passed to reference");
|
|
return *t;
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* Voider class template. Used to force a comiler to instantiate
|
|
* an otherwise probably unused template parameter type T.
|
|
* See the C++20 std::void_t <> for details.
|
|
*/
|
|
template <class T>
|
|
struct Void
|
|
{
|
|
typedef void Type;
|
|
};
|
|
|
|
|
|
/**
|
|
* Trait class that selects whether to return a user registered
|
|
* class object by value or by reference.
|
|
*/
|
|
|
|
template <class T, class Enabler = void>
|
|
struct UserdataGetter
|
|
{
|
|
typedef T* ReturnType;
|
|
|
|
static ReturnType get (lua_State* L, int index)
|
|
{
|
|
return Userdata::get <T> (L, index, false);
|
|
}
|
|
};
|
|
|
|
template <class T>
|
|
struct UserdataGetter <T, typename Void <T (*) ()>::Type>
|
|
{
|
|
typedef T ReturnType;
|
|
|
|
static ReturnType get (lua_State* L, int index)
|
|
{
|
|
return StackHelper <T, TypeTraits::isContainer <T>::value>::get (L, index);
|
|
}
|
|
};
|
|
|
|
//==============================================================================
|
|
|
|
/**
|
|
Lua stack conversions for class objects passed by value.
|
|
*/
|
|
template <class T>
|
|
struct Stack
|
|
{
|
|
typedef void IsUserdata;
|
|
|
|
typedef UserdataGetter <T> Getter;
|
|
typedef typename Getter::ReturnType ReturnType;
|
|
|
|
static void push (lua_State* L, T const& value)
|
|
{
|
|
StackHelper <T, TypeTraits::isContainer <T>::value>::push (L, value);
|
|
}
|
|
|
|
static ReturnType get (lua_State* L, int index)
|
|
{
|
|
return Getter::get (L, index);
|
|
}
|
|
|
|
static bool isInstance (lua_State* L, int index)
|
|
{
|
|
return Userdata::isInstance <T> (L, index);
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* Trait class indicating whether the parameter type must be
|
|
* a user registered class. The trait checks the existence of
|
|
* member type Stack <T>::IsUserdata specialization for detection.
|
|
*/
|
|
template <class T, class Enable = void>
|
|
struct IsUserdata
|
|
{
|
|
static const bool value = false;
|
|
};
|
|
|
|
template <class T>
|
|
struct IsUserdata <T, typename Void <typename Stack <T>::IsUserdata>::Type>
|
|
{
|
|
static const bool value = true;
|
|
};
|
|
|
|
|
|
/**
|
|
* Trait class that selects a specific push/get implemenation.
|
|
*/
|
|
template <class T, bool isUserdata>
|
|
struct StackOpSelector;
|
|
|
|
// pointer
|
|
template <class T>
|
|
struct StackOpSelector <T*, true>
|
|
{
|
|
typedef T* ReturnType;
|
|
|
|
static void push (lua_State* L, T* value)
|
|
{
|
|
UserdataPtr::push (L, value);
|
|
}
|
|
|
|
static T* get (lua_State* L, int index)
|
|
{
|
|
return Userdata::get <T> (L, index, false);
|
|
}
|
|
|
|
static bool isInstance (lua_State* L, int index)
|
|
{
|
|
return Userdata::isInstance <T> (L, index);
|
|
}
|
|
};
|
|
|
|
// pointer to const
|
|
template <class T>
|
|
struct StackOpSelector <const T*, true>
|
|
{
|
|
typedef const T* ReturnType;
|
|
|
|
static void push (lua_State* L, const T* value)
|
|
{
|
|
UserdataPtr::push (L, value);
|
|
}
|
|
|
|
static const T* get (lua_State* L, int index)
|
|
{
|
|
return Userdata::get <T> (L, index, true);
|
|
}
|
|
|
|
static bool isInstance (lua_State* L, int index)
|
|
{
|
|
return Userdata::isInstance <T> (L, index);
|
|
}
|
|
};
|
|
|
|
// reference
|
|
template <class T>
|
|
struct StackOpSelector <T&, true>
|
|
{
|
|
typedef RefStackHelper <T, TypeTraits::isContainer <T>::value> Helper;
|
|
typedef typename Helper::return_type ReturnType;
|
|
|
|
static void push (lua_State* L, T& value)
|
|
{
|
|
UserdataPtr::push (L, &value);
|
|
}
|
|
|
|
static ReturnType get (lua_State* L, int index)
|
|
{
|
|
return Helper::get (L, index);
|
|
}
|
|
|
|
static bool isInstance (lua_State* L, int index)
|
|
{
|
|
return Userdata::isInstance <T> (L, index);
|
|
}
|
|
};
|
|
|
|
// reference to const
|
|
template <class T>
|
|
struct StackOpSelector <const T&, true>
|
|
{
|
|
typedef RefStackHelper <T, TypeTraits::isContainer <T>::value> Helper;
|
|
typedef typename Helper::return_type ReturnType;
|
|
|
|
static void push (lua_State* L, const T& value)
|
|
{
|
|
Helper::push (L, value);
|
|
}
|
|
|
|
static ReturnType get (lua_State* L, int index)
|
|
{
|
|
return Helper::get (L, index);
|
|
}
|
|
|
|
static bool isInstance (lua_State* L, int index)
|
|
{
|
|
return Userdata::isInstance <T> (L, index);
|
|
}
|
|
};
|
|
|
|
} // namespace luabridge
|