int unpersist_l(lua_State *L) {
LoadInfo li;
/* perms? str? ...? */
lua_settop(L, 2);
/* perms? str? */
li.buf = luaL_checklstring(L, 2, &li.size);
/* perms? str */
lua_pop(L, 1);
/* It is conceivable that the buffer might now be collectable,
* which would cause problems in the reader. I can't think of
* any situation where there would be no other reference to the
* buffer, so for now I'll leave it alone, but this is a potential
* bug. */
/* perms? */
luaL_checktype(L, 1, LUA_TTABLE);
/* perms */
pluto_unpersist(L, bufreader, &li);
/* perms rootobj */
return 1;
}
bool LuaScriptEngine::unpersist(InputPersistenceBlock &reader) {
// Empty the Lua stack. pluto_persist() xepects that the stack is empty except for its parameters
lua_settop(_state, 0);
// Permanents table is placed on the stack. This has already happened at this point, because
// to create the table all permanents must be accessible. This is the case only for the
// beginning of the function, because the global table is emptied below
pushPermanentsTable(_state, PTT_UNPERSIST);
// All items from global table of _G and __METATABLES are removed.
// After a garbage collection is performed, and thus all managed objects deleted
// __METATABLES is not immediately removed becausen the Metatables are needed
// for the finalisers of objects.
static const char *clearExceptionsFirstPass[] = {
"_G",
"__METATABLES",
0
};
clearGlobalTable(_state, clearExceptionsFirstPass);
// In the second pass, the Metatables are removed
static const char *clearExceptionsSecondPass[] = {
"_G",
0
};
clearGlobalTable(_state, clearExceptionsSecondPass);
// Persisted Lua data
Common::Array<byte> chunkData;
reader.readByteArray(chunkData);
// Chunk-Reader initialisation. It is used with pluto_unpersist to restore read data
ChunkreaderData cd;
cd.BufferPtr = &chunkData[0];
cd.Size = chunkData.size();
cd.BufferReturned = false;
pluto_unpersist(_state, chunkreader, &cd);
// Permanents-Table is removed from stack
lua_remove(_state, -2);
// The read elements in the global table about
lua_pushnil(_state);
while (lua_next(_state, -2) != 0) {
// The referenec to the global table (_G) must not be overwritten, or ticks from Lua total
bool isGlobalReference = lua_isstring(_state, -2) && strcmp(lua_tostring(_state, -2), "_G") == 0;
if (!isGlobalReference) {
lua_pushvalue(_state, -2);
lua_pushvalue(_state, -2);
lua_settable(_state, LUA_GLOBALSINDEX);
}
// Pop value from the stack. The index is then ready for the next call to lua_next()
lua_pop(_state, 1);
}
// The table with the loaded data is popped from the stack
lua_pop(_state, 1);
// Force garbage collection
lua_gc(_state, LUA_GCCOLLECT, 0);
return true;
}