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Diffstat (limited to 'engines/sword25/util/lua_persist.cpp')
| -rw-r--r-- | engines/sword25/util/lua_persist.cpp | 804 |
1 files changed, 804 insertions, 0 deletions
diff --git a/engines/sword25/util/lua_persist.cpp b/engines/sword25/util/lua_persist.cpp new file mode 100644 index 0000000000..6fe88fe9a3 --- /dev/null +++ b/engines/sword25/util/lua_persist.cpp @@ -0,0 +1,804 @@ +/* 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 heavily based on the Pluto code base. Copyright below + */ + +/* Tamed Pluto - Heavy-duty persistence for Lua + * Copyright (C) 2004 by Ben Sunshine-Hill, and released into the public + * domain. People making use of this software as part of an application + * are politely requested to email the author at sneftel@gmail.com + * with a brief description of the application, primarily to satisfy his + * curiosity. + * + * 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. + * + * Instrumented by Stefan Reich (info@luaos.net) + * for Mobile Lua (http://luaos.net/pages/mobile-lua.php) + */ + + +#include "sword25/util/lua_persistence.h" + +#include "sword25/util/double_serialization.h" +#include "sword25/util/lua_persistence_util.h" + +#include "common/stream.h" + +#include "lua/lobject.h" +#include "lua/lstate.h" +#include "lua/lgc.h" + + +namespace Lua { + +#define PERMANENT_TYPE 101 + +struct SerializationInfo { + lua_State *luaState; + Common::WriteStream *writeStream; + uint counter; +}; + +static void persist(SerializationInfo *info); + +static void persistBoolean(SerializationInfo *info); +static void persistNumber(SerializationInfo *info); +static void persistString(SerializationInfo *info); +static void persistTable(SerializationInfo *info); +static void persistFunction(SerializationInfo *info); +static void persistThread(SerializationInfo *info); +static void persistProto(SerializationInfo *info); +static void persistUpValue(SerializationInfo *info); +static void persistUserData(SerializationInfo *info); + + +void persistLua(lua_State *luaState, Common::WriteStream *writeStream) { + SerializationInfo info; + info.luaState = luaState; + info.writeStream = writeStream; + info.counter = 1u; + + // The process starts with the lua stack as follows: + // >>>>> permTbl rootObj + // That's the table of permanents and the root object to be serialized + + // Make sure there is enough room on the stack + lua_checkstack(luaState, 4); + assert(lua_gettop(luaState) == 2); + // And that the root isn't nil + assert(!lua_isnil(luaState, 2)); + + // Create a table to hold indexes of everything that's serialized + // This allows us to only serialize an object once + // Every other time, just reference the index + lua_newtable(luaState); + // >>>>> permTbl rootObj indexTbl + + // Now we're going to make the table weakly keyed. This prevents the + // GC from visiting it and trying to mark things it doesn't want to + // mark in tables, e.g. upvalues. All objects in the table are + // a priori reachable, so it doesn't matter that we do this. + + // Create the metatable + lua_newtable(luaState); + // >>>>> permTbl rootObj indexTbl metaTbl + + lua_pushstring(luaState, "__mode"); + // >>>>> permTbl rootObj indexTbl metaTbl "__mode" + + lua_pushstring(luaState, "k"); + // >>>>> permTbl rootObj indexTbl metaTbl "__mode" "k" + + lua_settable(luaState, 4); + // >>>>> permTbl rootObj indexTbl metaTbl + + lua_setmetatable(luaState, 3); + // >>>>> permTbl rootObj indexTbl + + // Swap the indexTable and the rootObj + lua_insert(luaState, 2); + // >>>>> permTbl indexTbl rootObj + + // Serialize the root recursively + persist(&info); + + // Return the stack back to the original state + lua_remove(luaState, 2); + // >>>>> permTbl rootObj +} + +static void persist(SerializationInfo *info) { + // The stack can potentially have many things on it + // The object we want to serialize is the item on the top of the stack + // >>>>> permTbl indexTbl rootObj ...... obj + + // Make sure there is enough room on the stack + lua_checkstack(info->luaState, 2); + + // If the object has already been written, don't write it again + // Instead write the index of the object from the indexTbl + + // Check the indexTbl + lua_pushvalue(info->luaState, -1); + // >>>>> permTbl indexTbl rootObj ...... obj obj + + lua_rawget(info->luaState, 2); + // >>>>> permTbl indexTbl rootObj ...... obj ?index? + + // If the index isn't nil, the object has already been written + if (!lua_isnil(info->luaState, -1)) { + // Write out a flag that indicates that it's an index + info->writeStream->writeByte(0); + + // Retrieve the index from the stack + uint *index = (uint *)lua_touserdata(info->luaState, -1); + + // Write out the index + info->writeStream->writeUint32LE(*index); + + // Pop the index off the stack + lua_pop(info->luaState, 1); + + return; + } + + // Pop the index/nil off the stack + lua_pop(info->luaState, 1); + + // If the obj itself is nil, we represent it as an index of 0 + if (lua_isnil(info->luaState, -1)) { + // Write out a flag that indicates that it's an index + info->writeStream->writeByte(0); + // Write out the index + info->writeStream->writeUint32LE(0); + + return; + } + + // Write out a flag that indicates that this is a real object + info->writeStream->writeByte(1); + + // Add the object to the indexTbl + + lua_pushvalue(info->luaState, -1); + // >>>>> permTbl indexTbl rootObj ...... obj obj + + uint *ref = (uint *)lua_newuserdata(info->luaState, sizeof(uint)); + *ref = ++(info->counter); + // >>>>> permTbl indexTbl rootObj ...... obj obj index + + lua_rawset(info->luaState, 2); + // >>>>> permTbl indexTbl rootObj ...... obj + + + // Write out the index + info->writeStream->writeUint32LE(info->counter); + + + // Objects that are in the permanents table are serialized in a special way + + lua_pushvalue(info->luaState, -1); + // >>>>> permTbl indexTbl rootObj ...... obj obj + + lua_gettable(info->luaState, 1); + // >>>>> permTbl indexTbl rootObj ...... obj obj ?permKey? + + if (!lua_isnil(info->luaState, -1)) { + // Write out the type + info->writeStream->writeSint32LE(PERMANENT_TYPE); + + // Serialize the key + persist(info); + + // Pop the key off the stack + lua_pop(info->luaState, 1); + + return; + } + + // Pop the nil off the stack + lua_pop(info->luaState, 1); + + // Query the type of the object + int objType = lua_type(info->luaState, -1); + + // Write it out + info->writeStream->writeSint32LE(objType); + + // Serialize the object by its type + + switch (objType) { + case LUA_TBOOLEAN: + persistBoolean(info); + break; + case LUA_TLIGHTUSERDATA: + // You can't serialize a pointer + // It would be meaningless on the next run + assert(0); + break; + case LUA_TNUMBER: + persistNumber(info); + break; + case LUA_TSTRING: + persistString(info); + break; + case LUA_TTABLE: + persistTable(info); + break; + case LUA_TFUNCTION: + persistFunction(info); + break; + case LUA_TTHREAD: + persistThread(info); + break; + case LUA_TPROTO: + persistProto(info); + break; + case LUA_TUPVAL: + persistUpValue(info); + break; + case LUA_TUSERDATA: + persistUserData(info); + break; + default: + assert(0); + } +} + +static void persistBoolean(SerializationInfo *info) { + int value = lua_toboolean(info->luaState, -1); + + info->writeStream->writeSint32LE(value); +} + +static void persistNumber(SerializationInfo *info) { + lua_Number value = lua_tonumber(info->luaState, -1); + + Util::SerializedDouble serializedValue(Util::encodeDouble(value)); + + info->writeStream->writeUint32LE(serializedValue.significandOne); + info->writeStream->writeUint32LE(serializedValue.signAndSignificandTwo); + info->writeStream->writeSint16LE(serializedValue.exponent); +} + +static void persistString(SerializationInfo *info) { + // Hard cast to a uint32 to force size_t to an explicit size + // *Theoretically* this could truncate, but if we have a 4gb string, we have bigger problems + uint32 length = static_cast<uint32>(lua_strlen(info->luaState, -1)); + info->writeStream->writeUint32LE(length); + + const char *str = lua_tostring(info->luaState, -1); + info->writeStream->write(str, length); +} + +/* Choose whether to do a regular or special persistence based on an object's + * metatable. "default" is whether the object, if it doesn't have a __persist + * entry, is literally persistable or not. + * Pushes the unpersist closure and returns true if special persistence is + * used. */ +static bool serializeSpecialObject(SerializationInfo *info, bool defaction) { + // Make sure there is enough room on the stack + lua_checkstack(info->luaState, 4); + + // Check whether we should persist literally, or via the __persist metafunction + if (!lua_getmetatable(info->luaState, -1)) { + if (defaction) { + // Write out a flag declaring that the object isn't special and should be persisted normally + info->writeStream->writeSint32LE(0); + + return false; + } else { + lua_pushstring(info->luaState, "Type not literally persistable by default"); + lua_error(info->luaState); + + return false; // Not reached + } + } + + // >>>>> permTbl indexTbl ...... obj metaTbl + lua_pushstring(info->luaState, "__persist"); + // >>>>> permTbl indexTbl rootObj ...... obj metaTbl "__persist" + + lua_rawget(info->luaState, -2); + // >>>>> permTbl indexTbl ...... obj metaTbl ?__persist? + + if (lua_isnil(info->luaState, -1)) { + // >>>>> permTbl indexTbl ...... obj metaTbl nil + lua_pop(info->luaState, 2); + // >>>>> permTbl indexTbl ...... obj + + if (defaction) { + // Write out a flag declaring that the object isn't special and should be persisted normally + info->writeStream->writeSint32LE(0); + + return false; + } else { + lua_pushstring(info->luaState, "Type not literally persistable by default"); + lua_error(info->luaState); + + return false; // Return false + } + + } else if (lua_isboolean(info->luaState, -1)) { + // >>>>> permTbl indexTbl ...... obj metaTbl bool + if (lua_toboolean(info->luaState, -1)) { + // Write out a flag declaring that the object isn't special and should be persisted normally + info->writeStream->writeSint32LE(0); + + // >>>>> permTbl indexTbl ...... obj metaTbl true */ + lua_pop(info->luaState, 2); + // >>>>> permTbl indexTbl ...... obj + + return false; + } else { + lua_pushstring(info->luaState, "Metatable forbade persistence"); + lua_error(info->luaState); + + return false; // Not reached + } + } else if (!lua_isfunction(info->luaState, -1)) { + lua_pushstring(info->luaState, "__persist not nil, boolean, or function"); + lua_error(info->luaState); + } + + // >>>>> permTbl indexTbl ...... obj metaTbl __persist + lua_pushvalue(info->luaState, -3); + // >>>>> permTbl indexTbl ...... obj metaTbl __persist obj + + // >>>>> permTbl indexTbl ...... obj metaTbl ?func? + + if (!lua_isfunction(info->luaState, -1)) { + lua_pushstring(info->luaState, "__persist function did not return a function"); + lua_error(info->luaState); + } + + // >>>>> permTbl indexTbl ...... obj metaTbl func + + // Write out a flag that the function exists + info->writeStream->writeSint32LE(1); + + // Serialize the function + persist(info); + + lua_pop(info->luaState, 2); + // >>>>> permTbl indexTbl ...... obj + + return true; +} + +static void persistTable(SerializationInfo *info) { + // >>>>> permTbl indexTbl ...... tbl + + // Make sure there is enough room on the stack + lua_checkstack(info->luaState, 3); + + // Test if the object needs special serialization + if (serializeSpecialObject(info, 1)) { + return; + } + + // >>>>> permTbl indexTbl ...... tbl + + // First, serialize the metatable (if any) + if (!lua_getmetatable(info->luaState, -1)) { + lua_pushnil(info->luaState); + } + + // >>>>> permTbl indexTbl ...... tbl metaTbl/nil */ + persist(info); + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... tbl + + + lua_pushnil(info->luaState); + // >>>>> permTbl indexTbl ...... tbl nil + + // Now, persist all k/v pairs + while (lua_next(info->luaState, -2)) { + // >>>>> permTbl indexTbl ...... tbl k v */ + + lua_pushvalue(info->luaState, -2); + // >>>>> permTbl indexTbl ...... tbl k v k */ + + // Serialize the key + persist(info); + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... tbl k v */ + + // Serialize the value + persist(info); + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... tbl k */ + } + + // >>>>> permTbl indexTbl ...... tbl + + // Terminate the list with a nil + lua_pushnil(info->luaState); + // >>>>> permTbl indexTbl ...... tbl + + persist(info); + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... tbl +} + +static void persistFunction(SerializationInfo *info) { + // >>>>> permTbl indexTbl ...... func + Closure *cl = clvalue(getObject(info->luaState, -1)); + lua_checkstack(info->luaState, 2); + + if (cl->c.isC) { + /* It's a C function. For now, we aren't going to allow + * persistence of C closures, even if the "C proto" is + * already in the permanents table. */ + lua_pushstring(info->luaState, "Attempt to persist a C function"); + lua_error(info->luaState); + } else { + // It's a Lua closure + + // We don't really _NEED_ the number of upvals, but it'll simplify things a bit + info->writeStream->writeByte(cl->l.p->nups); + + // Serialize the prototype + pushProto(info->luaState, cl->l.p); + // >>>>> permTbl indexTbl ...... func proto */ + + persist(info); + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... func + + // Serialize upvalue values (not the upvalue objects themselves) + for (byte i = 0; i < cl->l.p->nups; i++) { + // >>>>> permTbl indexTbl ...... func + pushUpValue(info->luaState, cl->l.upvals[i]); + // >>>>> permTbl indexTbl ...... func upval + + persist(info); + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... func + } + + // >>>>> permTbl indexTbl ...... func + + // Serialize function environment + lua_getfenv(info->luaState, -1); + // >>>>> permTbl indexTbl ...... func fenv + + if (lua_equal(info->luaState, -1, LUA_GLOBALSINDEX)) { + // Function has the default fenv + + // >>>>> permTbl indexTbl ...... func _G + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... func + + lua_pushnil(info->luaState); + // >>>>> permTbl indexTbl ...... func nil + } + + // >>>>> permTbl indexTbl ...... func fenv/nil + persist(info); + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... func + } +} + +static void persistThread(SerializationInfo *info) { + // >>>>> permTbl indexTbl ...... thread + lua_State *threadState = lua_tothread(info->luaState, -1); + + // Make sure there is enough room on the stack + lua_checkstack(info->luaState, threadState->top - threadState->stack + 1); + + if (info->luaState == threadState) { + lua_pushstring(info->luaState, "Can't persist currently running thread"); + lua_error(info->luaState); + return; /* not reached */ + } + + // Persist the stack + + // We *could* have truncation here, but if we have more than 4 billion items on a stack, we have bigger problems + uint32 stackSize = static_cast<uint32>(appendStackToStack_reverse(threadState, info->luaState)); + info->writeStream->writeUint32LE(stackSize); + + // >>>>> permTbl indexTbl ...... thread (reversed contents of thread stack) */ + for (; stackSize > 0; --stackSize) { + persist(info); + + lua_pop(info->luaState, 1); + } + + // >>>>> permTbl indexTbl ...... thread + + // Now, serialize the CallInfo stack + + // Again, we *could* have truncation here, but if we have more than 4 billion items on a stack, we have bigger problems + uint32 numFrames = static_cast<uint32>((threadState->ci - threadState->base_ci) + 1); + info->writeStream->writeUint32LE(numFrames); + + for (uint32 i = 0; i < numFrames; i++) { + CallInfo *ci = threadState->base_ci + i; + + // Same argument as above about truncation + uint32 stackBase = static_cast<uint32>(ci->base - threadState->stack); + uint32 stackFunc = static_cast<uint32>(ci->func - threadState->stack); + uint32 stackTop = static_cast<uint32>(ci->top - threadState->stack); + + info->writeStream->writeUint32LE(stackBase); + info->writeStream->writeUint32LE(stackFunc); + info->writeStream->writeUint32LE(stackTop); + + info->writeStream->writeSint32LE(ci->nresults); + + uint32 savedpc = (ci != threadState->base_ci) ? static_cast<uint32>(ci->savedpc - ci_func(ci)->l.p->code) : 0u; + info->writeStream->writeUint32LE(savedpc); + } + + + // Serialize the state's other parameters, with the exception of upval stuff + + assert(threadState->nCcalls <= 1); + info->writeStream->writeByte(threadState->status); + + // Same argument as above about truncation + uint32 stackBase = static_cast<uint32>(threadState->base - threadState->stack); + uint32 stackFunc = static_cast<uint32>(threadState->top - threadState->stack); + info->writeStream->writeUint32LE(stackBase); + info->writeStream->writeUint32LE(stackFunc); + + // Same argument as above about truncation + uint32 stackOffset = static_cast<uint32>(threadState->errfunc); + info->writeStream->writeUint32LE(stackOffset); + + // Finally, record upvalues which need to be reopened + // See the comment above serializeUpVal() for why we do this + + UpVal *upVal; + + // >>>>> permTbl indexTbl ...... thread + for (GCObject *gcObject = threadState->openupval; gcObject != NULL; gcObject = upVal->next) { + upVal = gco2uv(gcObject); + + /* Make sure upvalue is really open */ + assert(upVal->v != &upVal->u.value); + + pushUpValue(info->luaState, upVal); + // >>>>> permTbl indexTbl ...... thread upVal + + persist(info); + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... thread + + // Same argument as above about truncation + uint32 stackpos = static_cast<uint32>(upVal->v - threadState->stack); + info->writeStream->writeUint32LE(stackpos); + } + + // >>>>> permTbl indexTbl ...... thread + lua_pushnil(info->luaState); + // >>>>> permTbl indexTbl ...... thread nil + + // Use nil as a terminator + persist(info); + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... thread +} + +static void persistProto(SerializationInfo *info) { + // >>>>> permTbl indexTbl ...... proto + Proto *proto = gco2p(getObject(info->luaState, -1)->value.gc); + + // Make sure there is enough room on the stack + lua_checkstack(info->luaState, 2); + + // Serialize constant refs */ + info->writeStream->writeSint32LE(proto->sizek); + + for (int i = 0; i < proto->sizek; ++i) { + pushObject(info->luaState, &proto->k[i]); + // >>>>> permTbl indexTbl ...... proto const + + persist(info); + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... proto + } + + // >>>>> permTbl indexTbl ...... proto + + // Serialize inner Proto refs + info->writeStream->writeSint32LE(proto->sizep); + + for (int i = 0; i < proto->sizep; ++i) + { + pushProto(info->luaState, proto->p[i]); + // >>>>> permTbl indexTbl ...... proto subProto */ + + persist(info); + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... proto + } + + // >>>>> permTbl indexTbl ...... proto + + // Serialize the code + info->writeStream->writeSint32LE(proto->sizecode); + + uint32 len = static_cast<uint32>(sizeof(Instruction) * proto->sizecode); + info->writeStream->write(proto->code, len); + + + // Serialize upvalue names + info->writeStream->writeSint32LE(proto->sizeupvalues); + + for (int i = 0; i < proto->sizeupvalues; ++i) + { + pushString(info->luaState, proto->upvalues[i]); + // >>>>> permTbl indexTbl ...... proto str + + persist(info); + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... proto + } + + + // Serialize local variable infos + info->writeStream->writeSint32LE(proto->sizelocvars); + + for (int i = 0; i < proto->sizelocvars; ++i) { + pushString(info->luaState, proto->locvars[i].varname); + // >>>>> permTbl indexTbl ...... proto str + + persist(info); + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... proto + + info->writeStream->writeSint32LE(proto->locvars[i].startpc); + info->writeStream->writeSint32LE(proto->locvars[i].endpc); + } + + + // Serialize source string + pushString(info->luaState, proto->source); + // >>>>> permTbl indexTbl ...... proto sourceStr + + persist(info); + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... proto + + // Serialize line numbers + info->writeStream->writeSint32LE(proto->sizelineinfo); + + if (proto->sizelineinfo) { + uint32 len = static_cast<uint32>(sizeof(int) * proto->sizelineinfo); + info->writeStream->write(proto->lineinfo, len); + } + + // Serialize linedefined and lastlinedefined + info->writeStream->writeSint32LE(proto->linedefined); + info->writeStream->writeSint32LE(proto->lastlinedefined); + + + // Serialize misc values + info->writeStream->writeByte(proto->nups); + info->writeStream->writeByte(proto->numparams); + info->writeStream->writeByte(proto->is_vararg); + info->writeStream->writeByte(proto->maxstacksize); +} + +/* Upvalues are tricky. Here's why. + * + * A particular upvalue may be either "open", in which case its member v + * points into a thread's stack, or "closed" in which case it points to the + * upvalue itself. An upvalue is closed under any of the following conditions: + * -- The function that initially declared the variable "local" returns + * -- The thread in which the closure was created is garbage collected + * + * To make things wackier, just because a thread is reachable by Lua doesn't + * mean it's in our root set. We need to be able to treat an open upvalue + * from an unreachable thread as a closed upvalue. + * + * The solution: + * (a) For the purposes of serializing, don't indicate whether an upvalue is + * closed or not. + * (b) When unserializing, pretend that all upvalues are closed. + * (c) When serializing, persist all open upvalues referenced by a thread + * that is persisted, and tag each one with the corresponding stack position + * (d) When unserializing, "reopen" each of these upvalues as the thread is + * unserialized + */ +static void persistUpValue(SerializationInfo *info) { + // >>>>> permTbl indexTbl ...... upval + assert(ttype(getObject(info->luaState, -1)) == LUA_TUPVAL); + UpVal *upValue = gco2uv(getObject(info->luaState, -1)->value.gc); + + // Make sure there is enough room on the stack + lua_checkstack(info->luaState, 1); + + // We can't permit the upValue to linger around on the stack, as Lua + // will bail if its GC finds it. + + lua_pop(info->luaState, 1); + // >>>>> permTbl indexTbl ...... + + pushObject(info->luaState, upValue->v); + // >>>>> permTbl indexTbl ...... obj + + persist(info); + // >>>>> permTbl indexTbl ...... obj +} + +static void persistUserData(SerializationInfo *info) { + // >>>>> permTbl rootObj ...... udata + + // Make sure there is enough room on the stack + lua_checkstack(info->luaState, 2); + + // Test if the object needs special serialization + if (serializeSpecialObject(info, 0)) { + return; + } + + // Use literal persistence + + // Hard cast to a uint32 length + // This could lead to truncation, but if we have a 4gb block of data, we have bigger problems + uint32 length = static_cast<uint32>(uvalue(getObject(info->luaState, -1))->len); + info->writeStream->writeUint32LE(length); + + info->writeStream->write(lua_touserdata(info->luaState, -1), length); + + // Serialize the metatable (if any) + if (!lua_getmetatable(info->luaState, -1)) { + lua_pushnil(info->luaState); + } + + // >>>>> permTbl rootObj ...... udata metaTbl/nil + persist(info); + + lua_pop(info->luaState, 1); + /* perms reftbl ... udata */ +} + + +} // End of namespace Lua |