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// LuaUtil: Various additional functions for working with lua
// Copyright (C) 2011 Pavel Labath
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "LuaUtil.hh"
namespace FbTk {
namespace {
const char newindexDenyWriteName[] = "FbTk::Lua::newindexDenyWrite";
const char newindexDenyModifyName[] = "FbTk::Lua::newindexDenyModify";
int newindexDenyWrite(lua::state *l) {
if(l->isstring(-2))
throw std::runtime_error("Cannot modify field '" + l->tostring(-2) + "'.");
else
throw std::runtime_error("Cannot modify this field.");
}
int newindexDenyModify(lua::state *l) {
bool ok = false;
l->getmetatable(-3); {
l->rawgetfield(-1, "__index"); {
l->pushvalue(-4); l->rawget(-2); {
if(l->isnil(-1))
ok = true;
} l->pop();
} l->pop();
} l->pop();
if(ok)
l->rawset(-3);
else
newindexDenyWrite(l);
return 0;
}
} // anonymous namespace
Lua::InitFunctions Lua::s_init_functions;
Lua::Lua() {
checkstack(1);
lua::stack_sentry s(*this);
pushfunction(&newindexDenyWrite);
rawsetfield(lua::REGISTRYINDEX, newindexDenyWriteName);
pushfunction(&newindexDenyModify);
rawsetfield(lua::REGISTRYINDEX, newindexDenyModifyName);
makeReadOnly(lua::GLOBALSINDEX, true);
InitFunctions::const_iterator it_end = s_init_functions.end();
for(InitFunctions::const_iterator it = s_init_functions.begin(); it != it_end; ++it)
(**it)(*this);
}
void Lua::makeReadOnly(int index, bool only_existing_fields) {
checkstack(6);
lua::stack_sentry s(*this);
index = absindex(index);
newtable(); {
newtable(); {
pushnil(); while(next(index)) {
pushvalue(-2); pushvalue(-2); rawset(-5);
pop(); pushnil(); rawset(index);
pushnil();
}
} rawsetfield(-2, "__index");
rawgetfield(lua::REGISTRYINDEX,
only_existing_fields ? newindexDenyModifyName : newindexDenyWriteName);
rawsetfield(-2, "__newindex");
pushboolean(false);
rawsetfield(-2, "__metatable");
} setmetatable(index);
}
void Lua::readOnlySet(int index) {
checkstack(2);
lua::stack_sentry s(*this, -2);
getmetatable(index); {
rawgetfield(-1, "__index"); insert(-4);
} pop();
rawset(-3);
pop();
}
void Lua::readOnlySetField(int index, const char *k) {
checkstack(1);
index = absindex(index);
pushstring(k);
insert(-2);
readOnlySet(index);
}
} // namespace FbTk
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