- * @brief Pops a value from the stack of a source state and pushes it on the
- * stack of another state.
- *
- * If the value is a table, its content is copied recursively. To avoid cycles,
- * a table of previsously visited tables must be present at index 1 of dst.
- * Its keys are pointers to visited tables in src and its values are the tables
- * already built.
- *
- * TODO: add support of closures
- *
- * @param src the source state
- * @param dst the destination state
- * @param name a name describing the value
- */
-static void move_value(lua_State* dst, lua_State *src, const char* name) {
-
- luaL_checkany(src, -1); /* check the value to copy */
- luaL_checktype(dst, 1, LUA_TTABLE); /* check the presence of a table of
- previously visited tables */
-
- int indentation_level = (lua_gettop(dst) - 1) * 6;
- const char* indent = get_spaces(indentation_level);
-
- XBT_DEBUG("%sCopying value %s", indent, name);
- indent = get_spaces(indentation_level + 2);
-
- stack_dump("src before copying a value (should be ... value): ", src);
- stack_dump("dst before copying a value (should be visited ...): ", dst);
-
- switch (lua_type(src, -1)) {
-
- case LUA_TNIL:
- lua_pushnil(dst);
- break;
-
- case LUA_TNUMBER:
- lua_pushnumber(dst, lua_tonumber(src, -1));
- break;
-
- case LUA_TBOOLEAN:
- lua_pushboolean(dst, lua_toboolean(src, -1));
- break;
-
- case LUA_TSTRING:
- /* no worries about memory: lua_pushstring makes a copy */
- lua_pushstring(dst, lua_tostring(src, -1));
- break;
-
- case LUA_TFUNCTION:
- /* it's a function that does not exist yet in L2 */
-
- if (lua_iscfunction(src, -1)) {
- /* it's a C function: just copy the pointer */
- lua_CFunction f = lua_tocfunction(src, -1);
- lua_pushcfunction(dst, f);
- }
- else {
- /* it's a Lua function: dump it from src */
- XBT_DEBUG("%sDumping Lua function '%s'", indent, name);
-
- s_buffer_t buffer;
- buffer.capacity = 64;
- buffer.size = 0;
- buffer.data = xbt_new(char, buffer.capacity);
-
- /* copy the binary chunk from src into a buffer */
- int error = lua_dump(src, writer, &buffer);
- xbt_assert(!error, "Failed to dump function '%s' from the source state: error %d",
- name, error);
-
- /* load the chunk into dst */
- error = luaL_loadbuffer(dst, buffer.data, buffer.size, name);
- xbt_assert(!error, "Failed to load function '%s' from the source state: %s",
- name, lua_tostring(dst, -1));
- XBT_DEBUG("%sFunction '%s' successfully dumped from source state.", indent, name);
- }
- break;
-
- case LUA_TTABLE:
-
- /* see if this table was already visited */
- lua_pushlightuserdata(dst, (void*) lua_topointer(src, -1));
- /* dst: visited ... psrctable */
- lua_gettable(dst, 1);
- /* dst: visited ... table/nil */
- if (lua_istable(dst, -1)) {
- XBT_DEBUG("%sNothing to do: table already visited", indent);
- /* dst: visited ... table */
- }
- else {
- XBT_DEBUG("%sFirst visit of this table", indent);
- /* dst: visited ... nil */
- lua_pop(dst, 1);
- /* dst: visited ... */
-
- /* first visit: create the new table in dst */
- lua_newtable(dst);
- /* dst: visited ... table */
-
- /* mark the table as visited to avoid infinite recursion */
- lua_pushlightuserdata(dst, (void*) lua_topointer(src, -1));
- /* dst: visited ... table psrctable */
- lua_pushvalue(dst, -2);
- /* dst: visited ... table psrctable table */
- lua_settable(dst, 1);
- /* dst: visited ... table */
- XBT_DEBUG("%sTable marked as visited", indent);
-
- stack_dump("dst after marking the table as visited (should be visited ... table): ", dst);
-
- /* copy the metatable if any */
- int has_meta_table = lua_getmetatable(src, -1);
- /* src: ... table mt? */
- if (has_meta_table) {
- XBT_DEBUG("%sCopying metatable", indent);
- /* src: ... table mt */
- move_value(dst, src, "metatable");
- /* src: ... table
- dst: visited ... table mt */
- lua_setmetatable(dst, -2);
- /* dst: visited ... table */
- }
- else {
- XBT_DEBUG("%sNo metatable", indent);
- }
-
- stack_dump("src before traversing the table (should be ... table): ", src);
- stack_dump("dst before traversing the table (should be visited ... table): ", dst);
-
- /* traverse the table of src and copy each element */
- lua_pushnil(src);
- /* src: ... table nil */
- while (lua_next(src, -2) != 0) {
- /* src: ... table key value */
-
- XBT_DEBUG("%sCopying table element %s", indent, keyvalue_tostring(src, -2, -1));
- indent = get_spaces(indentation_level + 4);
-
- stack_dump("src before copying table element (should be ... table key value): ", src);
- stack_dump("dst before copying table element (should be visited ... table): ", dst);
-
- /* copy the key */
- lua_pushvalue(src, -2);
- /* src: ... table key value key */
- XBT_DEBUG("%sCopying the key part of the table element", indent);
- move_value(dst, src, value_tostring(src, -1));
- /* src: ... table key value
- dst: visited ... table key */
- XBT_DEBUG("%sCopied the key part of the table element", indent);
-
- /* copy the value */
- XBT_DEBUG("%sCopying the value part of the table element", indent);
- move_value(dst, src, value_tostring(src, -1));
- /* src: ... table key
- dst: visited ... table key value */
- XBT_DEBUG("%sCopied the value part of the table element", indent);
-
- /* set the table element */
- lua_settable(dst, -3);
- /* dst: visited ... table */
-
- /* the key stays on top of src for next iteration */
- stack_dump("src before next iteration (should be ... table key): ", src);
- stack_dump("dst before next iteration (should be visited ... table): ", dst);
-
- indent = get_spaces(indentation_level + 2);
- }
- XBT_DEBUG("%sFinished traversing the table", indent);
- }
- break;
-
- case LUA_TLIGHTUSERDATA:
- lua_pushlightuserdata(dst, lua_touserdata(src, -1));
- break;
-
- case LUA_TUSERDATA:
- XBT_WARN("Copying a full userdata is not supported yet.");
- lua_pushnil(dst);
- break;
-
- case LUA_TTHREAD:
- XBT_WARN("Cannot copy a thread from the source state.");
- lua_pushnil(dst);
- break;
- }
-
- /* pop the value from src */
- lua_pop(src, 1);
-
- indent = get_spaces(indentation_level);
- XBT_DEBUG("%sCopied the value", indent);
-
- stack_dump("src after copying a value (should be ...): ", src);
- stack_dump("dst after copying a value (should be visited ... value): ", dst);
-}
-
-/**
- * @brief Copies a global value from the father state.