From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp54.i.mail.ru (smtp54.i.mail.ru [217.69.128.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id 4C37D44643C for ; Thu, 24 Sep 2020 20:01:02 +0300 (MSK) From: Timur Safin Date: Thu, 24 Sep 2020 20:00:18 +0300 Message-Id: <6fc62e3a3935978b650fd6d1dcbdef9a5353a1fb.1600955781.git.tsafin@tarantool.org> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Tarantool-patches] [PATCH 2.X 5/7] module api: luaT_temp_luastate & luaT_release_temp_luastate List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: v.shpilevoy@tarantool.org, alexander.turenko@tarantool.org Cc: tarantool-patches@dev.tarantool.org Moved `luaT_temp_luastate` & `luaT_release_temp_luastate` from merger to ustil.c and made them public. They were necessary for external merger support. Part of #5273 --- src/box/lua/merger.c | 78 -------------------------------------------- src/exports.h | 2 ++ src/lua/utils.c | 49 ++++++++++++++++++++++++++++ src/lua/utils.h | 35 ++++++++++++++++++++ 4 files changed, 86 insertions(+), 78 deletions(-) diff --git a/src/box/lua/merger.c b/src/box/lua/merger.c index 583946c4c..f26594049 100644 --- a/src/box/lua/merger.c +++ b/src/box/lua/merger.c @@ -149,84 +149,6 @@ luaT_gettuple(struct lua_State *L, int idx, struct tuple_format *format) return tuple; } -/** - * Get a temporary Lua state. - * - * Use case: a function does not accept a Lua state as an argument - * to allow using from C code, but uses a Lua value, which is - * referenced in LUA_REGISTRYINDEX. A temporary Lua stack is needed - * to get and process the value. - * - * The resulting Lua state has a separate Lua stack, but the same - * globals and registry as `tarantool_L` (and all Lua states in - * tarantool at the moment of writing this). - * - * This Lua state should be used only from one fiber: otherwise - * one fiber may change the stack and another one will access a - * wrong stack slot when it will be scheduled for execution after - * yield. - * - * Return a Lua state on success and set @a coro_ref and @a top. - * These values should be passed to - * `luaT_release_temp_luastate()`, when the state is not needed - * anymore. - * - * Return NULL and set a diag at failure. - */ -static struct lua_State * -luaT_temp_luastate(int *coro_ref, int *top) -{ - if (fiber()->storage.lua.stack != NULL) { - /* - * Reuse existing stack. In the releasing function - * we should drop a stack top to its initial - * value to don't exhaust available slots by - * many requests in row. - */ - struct lua_State *L = fiber()->storage.lua.stack; - *coro_ref = LUA_NOREF; - *top = lua_gettop(L); - return L; - } - - /* Popped by luaL_ref(). */ - struct lua_State *L = luaT_newthread(tarantool_L); - if (L == NULL) - return NULL; - /* - * We should remove the reference to the newly created Lua - * thread from tarantool_L, because of two reasons: - * - * First, if we'll push something to tarantool_L and - * yield, then another fiber will not know that a stack - * top is changed and may operate on a wrong slot. - * - * Second, many requests that push a value to tarantool_L - * and yield may exhaust available slots on the stack. It - * is limited by LUAI_MAXSTACK build time constant (~65K). - * - * We cannot just pop the value, but should keep the - * reference in the registry while it is in use. - * Otherwise it may be garbage collected. - */ - *coro_ref = luaL_ref(tarantool_L, LUA_REGISTRYINDEX); - *top = -1; - return L; -} - -/** - * Release a temporary Lua state. - * - * It complements `luaT_temp_luastate()`. - */ -static void -luaT_release_temp_luastate(struct lua_State *L, int coro_ref, int top) -{ - if (top >= 0) - lua_settop(L, top); - luaL_unref(tarantool_L, LUA_REGISTRYINDEX, coro_ref); -} - /* }}} */ /* {{{ Create, destroy structures from Lua */ diff --git a/src/exports.h b/src/exports.h index 1c16e88b2..ef4f3b741 100644 --- a/src/exports.h +++ b/src/exports.h @@ -416,7 +416,9 @@ EXPORT(luaT_error) EXPORT(luaT_istuple) EXPORT(luaT_newthread) EXPORT(luaT_pushtuple) +EXPORT(luaT_release_temp_luastate) EXPORT(luaT_state) +EXPORT(luaT_temp_luastate) EXPORT(luaT_tolstring) EXPORT(luaT_tuple_encode) EXPORT(luaT_tuple_new) diff --git a/src/lua/utils.c b/src/lua/utils.c index bf5452d3e..40078b5df 100644 --- a/src/lua/utils.c +++ b/src/lua/utils.c @@ -1259,6 +1259,55 @@ luaT_newthread(struct lua_State *L) return L1; } +struct lua_State * +luaT_temp_luastate(int *coro_ref, int *top) +{ + if (fiber()->storage.lua.stack != NULL) { + /* + * Reuse existing stack. In the releasing function + * we should drop a stack top to its initial + * value to don't exhaust available slots by + * many requests in row. + */ + struct lua_State *L = fiber()->storage.lua.stack; + *coro_ref = LUA_NOREF; + *top = lua_gettop(L); + return L; + } + + /* Popped by luaL_ref(). */ + struct lua_State *L = luaT_newthread(tarantool_L); + if (L == NULL) + return NULL; + /* + * We should remove the reference to the newly created Lua + * thread from tarantool_L, because of two reasons: + * + * First, if we'll push something to tarantool_L and + * yield, then another fiber will not know that a stack + * top is changed and may operate on a wrong slot. + * + * Second, many requests that push a value to tarantool_L + * and yield may exhaust available slots on the stack. It + * is limited by LUAI_MAXSTACK build time constant (~65K). + * + * We cannot just pop the value, but should keep the + * reference in the registry while it is in use. + * Otherwise it may be garbage collected. + */ + *coro_ref = luaL_ref(tarantool_L, LUA_REGISTRYINDEX); + *top = -1; + return L; +} + +void +luaT_release_temp_luastate(struct lua_State *L, int coro_ref, int top) +{ + if (top >= 0) + lua_settop(L, top); + luaL_unref(tarantool_L, LUA_REGISTRYINDEX, coro_ref); +} + int tarantool_lua_utils_init(struct lua_State *L) { diff --git a/src/lua/utils.h b/src/lua/utils.h index 9b1fe7e57..da0140076 100644 --- a/src/lua/utils.h +++ b/src/lua/utils.h @@ -554,6 +554,41 @@ luaL_iscallable(lua_State *L, int idx); struct lua_State * luaT_newthread(struct lua_State *L); +/** + * Get a temporary Lua state. + * + * Use case: a function does not accept a Lua state as an argument + * to allow using from C code, but uses a Lua value, which is + * referenced in LUA_REGISTRYINDEX. A temporary Lua stack is needed + * to get and process the value. + * + * The resulting Lua state has a separate Lua stack, but the same + * globals and registry as `tarantool_L` (and all Lua states in + * tarantool at the moment of writing this). + * + * This Lua state should be used only from one fiber: otherwise + * one fiber may change the stack and another one will access a + * wrong stack slot when it will be scheduled for execution after + * yield. + * + * Return a Lua state on success and set @a coro_ref and @a top. + * These values should be passed to + * `luaT_release_temp_luastate()`, when the state is not needed + * anymore. + * + * Return NULL and set a diag at failure. + */ +struct lua_State * +luaT_temp_luastate(int *coro_ref, int *top); + +/** + * Release a temporary Lua state. + * + * It complements `luaT_temp_luastate()`. + */ +void +luaT_release_temp_luastate(struct lua_State *L, int coro_ref, int top); + /** \endcond public */ /** -- 2.20.1