From: Vladimir Davydov <vdavydov.dev@gmail.com> To: Alexander Turenko <alexander.turenko@tarantool.org> Cc: tarantool-patches@freelists.org Subject: Re: [PATCH v2 2/6] Add functions to ease using Lua iterators from C Date: Thu, 10 Jan 2019 15:29:09 +0300 [thread overview] Message-ID: <20190110122909.novsa6o6duykot6a@esperanza> (raw) In-Reply-To: <2c8049118f86934d6088636dba44f92f381ef8ff.1547064388.git.alexander.turenko@tarantool.org> On Wed, Jan 09, 2019 at 11:20:10PM +0300, Alexander Turenko wrote: > Needed for #3276. Again, I'm not quite sure that you'll need this patch after you rework the merger API so I'm not applying it until you send the new API proposal. > --- > src/lua/utils.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++ > src/lua/utils.h | 28 +++++++++++++++++++++ Some tests would be nice to have. > 2 files changed, 94 insertions(+) > > diff --git a/src/lua/utils.c b/src/lua/utils.c > index eefb860ee..4d1eee6ab 100644 > --- a/src/lua/utils.c > +++ b/src/lua/utils.c > @@ -969,6 +969,72 @@ luaT_state(void) > return tarantool_L; > } > > +/* {{{ Helper functions to interact with a Lua iterator from C */ > + > +struct luaL_iterator { > + int gen; > + int param; > + int state; > +}; > + > +struct luaL_iterator * > +luaL_iterator_new_fromtable(lua_State *L, int idx) > +{ > + struct luaL_iterator *it = (struct luaL_iterator *) malloc( Nit: no need to convert void * to struct luaL_iterator *. > + sizeof(struct luaL_iterator)); > + > + lua_rawgeti(L, idx, 1); /* Popped by luaL_ref(). */ > + it->gen = luaL_ref(L, LUA_REGISTRYINDEX); > + lua_rawgeti(L, idx, 2); /* Popped by luaL_ref(). */ > + it->param = luaL_ref(L, LUA_REGISTRYINDEX); > + lua_rawgeti(L, idx, 3); /* Popped by luaL_ref(). */ > + it->state = luaL_ref(L, LUA_REGISTRYINDEX); > + > + return it; > +} > + > +int > +luaL_iterator_next(lua_State *L, struct luaL_iterator *it) > +{ > + int frame_start = lua_gettop(L); > + > + /* Call gen(param, state). */ > + lua_rawgeti(L, LUA_REGISTRYINDEX, it->gen); > + lua_rawgeti(L, LUA_REGISTRYINDEX, it->param); > + lua_rawgeti(L, LUA_REGISTRYINDEX, it->state); > + lua_call(L, 2, LUA_MULTRET); > + int nresults = lua_gettop(L) - frame_start; > + if (nresults == 0) { > + luaL_error(L, "luaL_iterator_next: gen(param, state) must " > + "return at least one result"); > + unreachable(); > + return 0; > + } > + > + /* The call above returns nil as the first result. */ > + if (lua_isnil(L, frame_start + 1)) { > + lua_settop(L, frame_start); > + return 0; > + } > + > + /* Save the first result to it->state. */ > + luaL_unref(L, LUA_REGISTRYINDEX, it->state); > + lua_pushvalue(L, frame_start + 1); /* Popped by luaL_ref(). */ > + it->state = luaL_ref(L, LUA_REGISTRYINDEX); > + > + return nresults; > +} > + > +void luaL_iterator_free(lua_State *L, struct luaL_iterator *it) > +{ > + luaL_unref(L, LUA_REGISTRYINDEX, it->gen); > + luaL_unref(L, LUA_REGISTRYINDEX, it->param); > + luaL_unref(L, LUA_REGISTRYINDEX, it->state); > + free(it); > +} > + > +/* }}} */ > + > int > tarantool_lua_utils_init(struct lua_State *L) > { > diff --git a/src/lua/utils.h b/src/lua/utils.h > index bd302d8e9..6ba2e4767 100644 > --- a/src/lua/utils.h > +++ b/src/lua/utils.h > @@ -525,6 +525,34 @@ luaL_checkfinite(struct lua_State *L, struct luaL_serializer *cfg, > luaL_error(L, "number must not be NaN or Inf"); > } > > +/* {{{ Helper functions to interact with a Lua iterator from C */ > + > +/** > + * Holds iterator state (references to Lua objects). > + */ > +struct luaL_iterator; I'd make luaL_iterator struct transparent so that one could define it on stack. > + > +/** > + * Create a Lua iterator from {gen, param, state}. May be, we could pass idx == 0 to create an iterator from gen, param, state (without a table)? Would it be worthwhile? > + */ > +struct luaL_iterator * > +luaL_iterator_new_fromtable(lua_State *L, int idx); I don't think that _fromtable suffix is really necessary. > + > +/** > + * Move iterator to the next value. Push values returned by > + * gen(param, state) and return its count. Zero means no more > + * results available. > + */ > +int > +luaL_iterator_next(lua_State *L, struct luaL_iterator *it); > + > +/** > + * Free all resources held by the iterator. > + */ > +void luaL_iterator_free(lua_State *L, struct luaL_iterator *it); We usually match _new with _delete. > + > +/* }}} */ > + > int > tarantool_lua_utils_init(struct lua_State *L);
next prev parent reply other threads:[~2019-01-10 12:29 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-01-09 20:20 [PATCH v2 0/6] Merger Alexander Turenko 2019-01-09 20:20 ` [PATCH v2 1/6] Add luaL_iscallable with support of cdata metatype Alexander Turenko 2019-01-10 12:21 ` Vladimir Davydov 2019-01-09 20:20 ` [PATCH v2 2/6] Add functions to ease using Lua iterators from C Alexander Turenko 2019-01-10 12:29 ` Vladimir Davydov [this message] 2019-01-15 23:26 ` Alexander Turenko 2019-01-16 8:18 ` Vladimir Davydov 2019-01-16 11:40 ` Alexander Turenko 2019-01-16 12:20 ` Vladimir Davydov 2019-01-17 1:20 ` Alexander Turenko 2019-01-28 18:17 ` Alexander Turenko 2019-03-01 4:04 ` Alexander Turenko 2019-01-09 20:20 ` [PATCH v2 3/6] lua: add luaT_newtuple() Alexander Turenko 2019-01-10 12:44 ` Vladimir Davydov 2019-01-18 21:58 ` Alexander Turenko 2019-01-23 16:12 ` Vladimir Davydov 2019-01-28 16:51 ` Alexander Turenko 2019-03-01 4:08 ` Alexander Turenko 2019-01-09 20:20 ` [PATCH v2 4/6] lua: add luaT_new_key_def() Alexander Turenko 2019-01-10 13:07 ` Vladimir Davydov 2019-01-29 18:52 ` Alexander Turenko 2019-01-30 10:58 ` Alexander Turenko 2019-03-01 4:10 ` Alexander Turenko 2019-01-09 20:20 ` [PATCH v2 5/6] net.box: add helpers to decode msgpack headers Alexander Turenko 2019-01-10 17:29 ` Vladimir Davydov 2019-02-01 15:11 ` Alexander Turenko 2019-03-05 12:00 ` Alexander Turenko 2019-01-09 20:20 ` [PATCH v2 6/6] Add merger for tuple streams Alexander Turenko
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