/* * Push a proxy userdata on the stack. * * Initializes necessary structures if it's the first time 'idfunc' is being * used in this Lua state (metatable, registring it). Otherwise, increments the * reference count. */ void luaG_push_proxy( lua_State *L, lua_CFunction idfunc, DEEP_PRELUDE *prelude ) { DEEP_PRELUDE **proxy; MUTEX_LOCK( &deep_lock ); ++(prelude->refcount); // one more proxy pointing to this deep data MUTEX_UNLOCK( &deep_lock ); STACK_GROW(L,4); STACK_CHECK(L) proxy= lua_newuserdata( L, sizeof( DEEP_PRELUDE* ) ); ASSERT_L(proxy); *proxy= prelude; // Get/create metatable for 'idfunc' (in this state) // lua_pushcfunction( L, idfunc ); // key get_deep_lookup(L); // // [-2]: proxy // [-1]: metatable / nil if (lua_isnil(L,-1)) { // No metatable yet; make one and register it // lua_pop(L,1); // tbl= idfunc( "metatable" ) // lua_pushcfunction( L, idfunc ); lua_pushliteral( L, "metatable" ); lua_call( L, 1 /*args*/, 1 /*results*/ ); // // [-2]: proxy // [-1]: metatable (returned by 'idfunc') if (!lua_istable(L,-1)) luaL_error( L, "Bad idfunc on \"metatable\": did not return one" ); // Add '__gc' method // lua_pushcfunction( L, deep_userdata_gc ); lua_setfield( L, -2, "__gc" ); // Memorize for later rounds // lua_pushvalue( L,-1 ); lua_pushcfunction( L, idfunc ); // // [-4]: proxy // [-3]: metatable (2nd ref) // [-2]: metatable // [-1]: idfunc set_deep_lookup(L); } STACK_MID(L,2) ASSERT_L( lua_isuserdata(L,-2) ); ASSERT_L( lua_istable(L,-1) ); // [-2]: proxy userdata // [-1]: metatable to use lua_setmetatable( L, -2 ); STACK_END(L,1) // [-1]: proxy userdata }
/* * Push a proxy userdata on the stack. * returns NULL if ok, else some error string related to bad idfunc behavior or module require problem * (error cannot happen with mode_ == eLM_ToKeeper) * * Initializes necessary structures if it's the first time 'idfunc' is being * used in this Lua state (metatable, registring it). Otherwise, increments the * reference count. */ char const* push_deep_proxy( struct s_Universe* U, lua_State* L, DEEP_PRELUDE* prelude, enum eLookupMode mode_) { DEEP_PRELUDE** proxy; // Check if a proxy already exists push_registry_subtable_mode( L, DEEP_PROXY_CACHE_KEY, "v"); // DPC lua_pushlightuserdata( L, prelude->deep); // DPC deep lua_rawget( L, -2); // DPC proxy if ( !lua_isnil( L, -1)) { lua_remove( L, -2); // proxy return NULL; } else { lua_pop( L, 1); // DPC } MUTEX_LOCK( &U->deep_lock); ++ (prelude->refcount); // one more proxy pointing to this deep data MUTEX_UNLOCK( &U->deep_lock); STACK_GROW( L, 7); STACK_CHECK( L); proxy = lua_newuserdata( L, sizeof( DEEP_PRELUDE*)); // DPC proxy ASSERT_L( proxy); *proxy = prelude; // Get/create metatable for 'idfunc' (in this state) lua_pushlightuserdata( L, prelude->idfunc); // DPC proxy idfunc get_deep_lookup( L); // DPC proxy metatable? if( lua_isnil( L, -1)) // // No metatable yet. { char const* modname; int oldtop = lua_gettop( L); // DPC proxy nil lua_pop( L, 1); // DPC proxy // 1 - make one and register it if( mode_ != eLM_ToKeeper) { prelude->idfunc( L, eDO_metatable); // DPC proxy metatable deepversion if( lua_gettop( L) - oldtop != 1 || !lua_istable( L, -2) || !lua_isstring( L, -1)) { lua_settop( L, oldtop); // DPC proxy X lua_pop( L, 3); // return "Bad idfunc(eOP_metatable): unexpected pushed value"; } luaG_pushdeepversion( L); // DPC proxy metatable deepversion deepversion if( !lua501_equal( L, -1, -2)) { lua_pop( L, 5); // return "Bad idfunc(eOP_metatable): mismatched deep version"; } lua_pop( L, 2); // DPC proxy metatable // make sure the idfunc didn't export __gc, as we will store our own lua_getfield( L, -1, "__gc"); // DPC proxy metatable __gc if( !lua_isnil( L, -1)) { lua_pop( L, 4); // return "idfunc-created metatable shouldn't contain __gc"; } lua_pop( L, 1); // DPC proxy metatable } else { // keepers need a minimal metatable that only contains __gc lua_newtable( L); // DPC proxy metatable } // Add our own '__gc' method lua_pushcfunction( L, deep_userdata_gc); // DPC proxy metatable __gc lua_setfield( L, -2, "__gc"); // DPC proxy metatable // Memorize for later rounds lua_pushvalue( L, -1); // DPC proxy metatable metatable lua_pushlightuserdata( L, prelude->idfunc); // DPC proxy metatable metatable idfunc set_deep_lookup( L); // DPC proxy metatable // 2 - cause the target state to require the module that exported the idfunc // this is needed because we must make sure the shared library is still loaded as long as we hold a pointer on the idfunc { int oldtop = lua_gettop( L); modname = (char const*) prelude->idfunc( L, eDO_module); // DPC proxy metatable // make sure the function pushed nothing on the stack! if( lua_gettop( L) - oldtop != 0) { lua_pop( L, 3); // return "Bad idfunc(eOP_module): should not push anything"; } } if( modname) // we actually got a module name { // somehow, L.registry._LOADED can exist without having registered the 'package' library. lua_getglobal( L, "require"); // DPC proxy metatable require() // check that the module is already loaded (or being loaded, we are happy either way) if( lua_isfunction( L, -1)) { lua_pushstring( L, modname); // DPC proxy metatable require() "module" lua_getfield( L, LUA_REGISTRYINDEX, "_LOADED"); // DPC proxy metatable require() "module" _R._LOADED if( lua_istable( L, -1)) { bool_t alreadyloaded; lua_pushvalue( L, -2); // DPC proxy metatable require() "module" _R._LOADED "module" lua_rawget( L, -2); // DPC proxy metatable require() "module" _R._LOADED module alreadyloaded = lua_toboolean( L, -1); if( !alreadyloaded) // not loaded { int require_result; lua_pop( L, 2); // DPC proxy metatable require() "module" // require "modname" require_result = lua_pcall( L, 1, 0, 0); // DPC proxy metatable error? if( require_result != LUA_OK) { // failed, return the error message lua_pushfstring( L, "error while requiring '%s' identified by idfunc(eOP_module): ", modname); lua_insert( L, -2); // DPC proxy metatable prefix error lua_concat( L, 2); // DPC proxy metatable error return lua_tostring( L, -1); } } else // already loaded, we are happy { lua_pop( L, 4); // DPC proxy metatable } } else // no L.registry._LOADED; can this ever happen? { lua_pop( L, 6); // return "unexpected error while requiring a module identified by idfunc(eOP_module)"; } } else // a module name, but no require() function :-( { lua_pop( L, 4); // return "lanes receiving deep userdata should register the 'package' library"; } } } STACK_MID( L, 2); // DPC proxy metatable ASSERT_L( lua_isuserdata( L, -2)); ASSERT_L( lua_istable( L, -1)); lua_setmetatable( L, -2); // DPC proxy // If we're here, we obviously had to create a new proxy, so cache it. lua_pushlightuserdata( L, (*proxy)->deep); // DPC proxy deep lua_pushvalue( L, -2); // DPC proxy deep proxy lua_rawset( L, -4); // DPC proxy lua_remove( L, -2); // proxy ASSERT_L( lua_isuserdata( L, -1)); STACK_END( L, 0); return NULL; }