[tarantool-patches] [PATCH v2 04/10] console: use Lua C API to do formatting for console
Konstantin Osipov
kostja at tarantool.org
Thu May 10 21:46:48 MSK 2018
* Vladislav Shpilevoy <v.shpilevoy at tarantool.org> [18/04/20 16:25]:
> YAML formatting C API is needed for #2677, where it will be used
> to send text pushes and prints as tagged YAML documents.
I don't understand why you need to move dump/format into C
from this comment.
What was wrong with keeping it in Lua implementation?
>
> Needed for #2677
> ---
> src/box/lua/console.c | 48 +++++++++++++++++++++++++++++++++++++++++++
> src/box/lua/console.lua | 32 ++++++-----------------------
> third_party/lua-yaml/lyaml.cc | 34 ++++++++++++------------------
> third_party/lua-yaml/lyaml.h | 29 ++++++++++++++++++++++++++
> 4 files changed, 96 insertions(+), 47 deletions(-)
>
> diff --git a/src/box/lua/console.c b/src/box/lua/console.c
> index d27d7ecac..f6009d387 100644
> --- a/src/box/lua/console.c
> +++ b/src/box/lua/console.c
> @@ -34,6 +34,7 @@
> #include "lua/fiber.h"
> #include "fiber.h"
> #include "coio.h"
> +#include "lua-yaml/lyaml.h"
> #include <lua.h>
> #include <lauxlib.h>
> #include <lualib.h>
> @@ -42,6 +43,8 @@
> #include <stdlib.h>
> #include <ctype.h>
>
> +static struct luaL_serializer *luaL_yaml_default = NULL;
> +
> /*
> * Completion engine (Mike Paul's).
> * Used internally when collecting completions locally. Also a Lua
> @@ -328,6 +331,32 @@ lbox_console_add_history(struct lua_State *L)
> return 0;
> }
>
> +/**
> + * Encode Lua object into YAML documents. Gets variable count of
> + * parameters.
> + * @retval String with YAML documents - one per parameter.
> + */
> +static int
> +lbox_console_format(struct lua_State *L)
> +{
> + int arg_count = lua_gettop(L);
> + if (arg_count == 0) {
> + lua_pushstring(L, "---\n...\n");
> + return 1;
> + }
> + lua_createtable(L, arg_count, 0);
> + for (int i = 0; i < arg_count; ++i) {
> + if (lua_isnil(L, i + 1))
> + luaL_pushnull(L);
> + else
> + lua_pushvalue(L, i + 1);
> + lua_rawseti(L, -2, i + 1);
> + }
> + lua_replace(L, 1);
> + lua_settop(L, 1);
> + return lua_yaml_encode(L, luaL_yaml_default);
> +}
> +
> void
> tarantool_lua_console_init(struct lua_State *L)
> {
> @@ -336,6 +365,7 @@ tarantool_lua_console_init(struct lua_State *L)
> {"save_history", lbox_console_save_history},
> {"add_history", lbox_console_add_history},
> {"completion_handler", lbox_console_completion_handler},
> + {"format", lbox_console_format},
> {NULL, NULL}
> };
> luaL_register_module(L, "console", consolelib);
> @@ -344,6 +374,24 @@ tarantool_lua_console_init(struct lua_State *L)
> lua_getfield(L, -1, "completion_handler");
> lua_pushcclosure(L, lbox_console_readline, 1);
> lua_setfield(L, -2, "readline");
> +
> + luaL_yaml_default = lua_yaml_new_serializer(L);
> + luaL_yaml_default->encode_invalid_numbers = 1;
> + luaL_yaml_default->encode_load_metatables = 1;
> + luaL_yaml_default->encode_use_tostring = 1;
> + luaL_yaml_default->encode_invalid_as_nil = 1;
> + /*
> + * Hold reference to a formatter (the Lua representation
> + * of luaL_yaml_default).
> It is not visible to a user
> + * here, because require('console') returns modified
> + * package with no formatter. This problem is absent in
> + * similar places like lua/msgpack.c, because they are
> + * serializers and nothing more - they hold
> + * luaL_serializer in LUA_REGISTRYINDEX. Console does the
> + * same, but here a YAML serializer is just a part of
> + * console.
> + */
I don't understand the comment beyond the first sentence.
> + lua_setfield(L, -2, "formatter");
> }
>
> /*
> +/**
> + * Encode a Lua object or objects into YAML documents onto Lua
> + * stack.
> + * @param L Lua stack to get arguments and push result.
> + * @param serializer Lua YAML serializer.
> + * @param tag_handle NULL, or a global tag handle. Handle becomes
> + * a synonym for prefix.
> + * @param tag_prefix NULL, or a global tag prefix, to which @a
> + * handle is expanded.
> + * @retval nil, error Error.
> + * @retval not nil Lua string with dumped object.
> + */
> +int
> +lua_yaml_encode_tagged(lua_State *L, struct luaL_serializer *serializer,
> + const char *tag_handle, const char *tag_prefix);
No need to keep the comments in two places. We have decided to
keep the comments around declarations, not definitions, a while
ago (please make sure to update the server engineering guidelines
if it is not reflected there or in the coding style).
> +
> +/** Same as lua_yaml_encode_tagged, but encode with no tags. */
> +static inline int
> +lua_yaml_encode(lua_State *L, struct luaL_serializer *serializer)
> +{
> + return lua_yaml_encode_tagged(L, serializer, NULL, NULL);
> +}
--
Konstantin Osipov, Moscow, Russia, +7 903 626 22 32
http://tarantool.io - www.twitter.com/kostja_osipov
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