mirror of https://github.com/lua/lua
new function 'loadin'
This commit is contained in:
Roberto Ierusalimschy
parent
7fe405739c
commit
b9063a08f5
84
lbaselib.c
84
lbaselib.c
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@ -1,5 +1,5 @@
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/*
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** $Id: lbaselib.c,v 1.221 2009/10/23 19:12:19 roberto Exp roberto $
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** $Id: lbaselib.c,v 1.222 2009/11/09 18:55:17 roberto Exp roberto $
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** Basic library
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** See Copyright Notice in lua.h
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*/
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@ -276,13 +276,11 @@ static int luaB_loadfile (lua_State *L) {
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/*
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** Reader for generic `load' function: `lua_load' uses the
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** stack for internal stuff, so the reader cannot change the
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** stack top. Instead, it keeps its resulting string in a
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** reserved slot inside the stack.
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** {======================================================
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** Generic Read function
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** =======================================================
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*/
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static const char *checkrights (lua_State *L, const char *mode, const char *s) {
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if (strchr(mode, 'b') == NULL && *s == LUA_SIGNATURE[0])
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return lua_pushstring(L, "attempt to load a binary chunk");
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@ -292,24 +290,42 @@ static const char *checkrights (lua_State *L, const char *mode, const char *s) {
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}
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/*
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** reserves a slot, above all arguments, to hold a copy of the returned
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** string to avoid it being collected while parsed
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*/
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#define RESERVEDSLOT 4
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/*
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** Reader for generic `load' function: `lua_load' uses the
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** stack for internal stuff, so the reader cannot change the
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** stack top. Instead, it keeps its resulting string in a
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** reserved slot inside the stack.
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*/
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typedef struct { /* reader state */
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int f; /* position of reader function on stack */
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const char *mode; /* allowed modes (binary/text) */
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} Readstat;
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static const char *generic_reader (lua_State *L, void *ud, size_t *size) {
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const char *s;
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const char **mode = (const char **)ud;
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Readstat *stat = (Readstat *)ud;
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luaL_checkstack(L, 2, "too many nested functions");
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lua_pushvalue(L, 1); /* get function */
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lua_pushvalue(L, stat->f); /* get function */
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lua_call(L, 0, 1); /* call it */
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if (lua_isnil(L, -1)) {
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*size = 0;
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return NULL;
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}
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else if ((s = lua_tostring(L, -1)) != NULL) {
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if (*mode != NULL) { /* first time? */
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s = checkrights(L, *mode, s); /* check whether chunk format is allowed */
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*mode = NULL; /* to avoid further checks */
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if (stat->mode != NULL) { /* first time? */
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s = checkrights(L, stat->mode, s); /* check mode */
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stat->mode = NULL; /* to avoid further checks */
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if (s) luaL_error(L, s);
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}
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lua_replace(L, 3); /* save string in a reserved stack slot */
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return lua_tolstring(L, 3, size);
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lua_replace(L, RESERVEDSLOT); /* save string in reserved slot */
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return lua_tolstring(L, RESERVEDSLOT, size);
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}
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else {
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luaL_error(L, "reader function must return a string");
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@ -318,30 +334,51 @@ static const char *generic_reader (lua_State *L, void *ud, size_t *size) {
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}
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static int luaB_load (lua_State *L) {
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static int luaB_load_aux (lua_State *L, int farg) {
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int status;
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const char *s = lua_tostring(L, 1);
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const char *mode = luaL_optstring(L, 3, "bt");
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Readstat stat;
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const char *s = lua_tostring(L, farg);
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stat.mode = luaL_optstring(L, farg + 2, "bt");
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if (s != NULL) { /* loading a string? */
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const char *chunkname = luaL_optstring(L, 2, s);
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status = (checkrights(L, mode, s) != NULL)
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|| luaL_loadbuffer(L, s, lua_objlen(L, 1), chunkname);
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const char *chunkname = luaL_optstring(L, farg + 1, s);
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status = (checkrights(L, stat.mode, s) != NULL)
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|| luaL_loadbuffer(L, s, lua_objlen(L, farg), chunkname);
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}
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else { /* loading from a reader function */
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const char *chunkname = luaL_optstring(L, 2, "=(load)");
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luaL_checktype(L, 1, LUA_TFUNCTION);
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lua_settop(L, 3); /* function, eventual name, plus one reserved slot */
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status = lua_load(L, generic_reader, &mode, chunkname);
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const char *chunkname = luaL_optstring(L, farg + 1, "=(load)");
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luaL_checktype(L, farg, LUA_TFUNCTION);
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stat.f = farg;
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lua_settop(L, RESERVEDSLOT); /* create reserved slot */
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status = lua_load(L, generic_reader, &stat, chunkname);
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}
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return load_aux(L, status);
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}
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static int luaB_load (lua_State *L) {
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return luaB_load_aux(L, 1);
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}
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static int luaB_loadin (lua_State *L) {
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int n;
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luaL_checktype(L, 1, LUA_TTABLE);
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n = luaB_load_aux(L, 2);
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if (n == 1) { /* success? */
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lua_pushvalue(L, 1); /* environment for loaded function */
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lua_setfenv(L, -2);
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}
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return n;
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}
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static int luaB_loadstring (lua_State *L) {
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lua_settop(L, 2);
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lua_pushliteral(L, "tb");
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return luaB_load(L); /* dostring(s, n) == load(s, n, "tb") */
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}
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/* }====================================================== */
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static int dofilecont (lua_State *L) {
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@ -481,6 +518,7 @@ static const luaL_Reg base_funcs[] = {
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{"getmetatable", luaB_getmetatable},
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{"loadfile", luaB_loadfile},
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{"load", luaB_load},
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{"loadin", luaB_loadin},
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{"loadstring", luaB_loadstring},
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{"next", luaB_next},
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{"pcall", luaB_pcall},
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