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new function 'loadin'

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This commit is contained in:
Roberto Ierusalimschy 2009-11-13 15:01:40 -02:00
parent 7fe405739c
commit b9063a08f5
1 changed files with 61 additions and 23 deletions
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84
lbaselib.c
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@ -1,5 +1,5 @@
/*
** $Id: lbaselib.c,v 1.221 2009/10/23 19:12:19 roberto Exp roberto $
** $Id: lbaselib.c,v 1.222 2009/11/09 18:55:17 roberto Exp roberto $
** Basic library
** See Copyright Notice in lua.h
*/
@ -276,13 +276,11 @@ static int luaB_loadfile (lua_State *L) {
/*
** Reader for generic `load' function: `lua_load' uses the
** stack for internal stuff, so the reader cannot change the
** stack top. Instead, it keeps its resulting string in a
** reserved slot inside the stack.
** {======================================================
** Generic Read function
** =======================================================
*/
static const char *checkrights (lua_State *L, const char *mode, const char *s) {
if (strchr(mode, 'b') == NULL && *s == LUA_SIGNATURE[0])
return lua_pushstring(L, "attempt to load a binary chunk");
@ -292,24 +290,42 @@ static const char *checkrights (lua_State *L, const char *mode, const char *s) {
}
/*
** reserves a slot, above all arguments, to hold a copy of the returned
** string to avoid it being collected while parsed
*/
#define RESERVEDSLOT 4
/*
** Reader for generic `load' function: `lua_load' uses the
** stack for internal stuff, so the reader cannot change the
** stack top. Instead, it keeps its resulting string in a
** reserved slot inside the stack.
*/
typedef struct { /* reader state */
int f; /* position of reader function on stack */
const char *mode; /* allowed modes (binary/text) */
} Readstat;
static const char *generic_reader (lua_State *L, void *ud, size_t *size) {
const char *s;
const char **mode = (const char **)ud;
Readstat *stat = (Readstat *)ud;
luaL_checkstack(L, 2, "too many nested functions");
lua_pushvalue(L, 1); /* get function */
lua_pushvalue(L, stat->f); /* get function */
lua_call(L, 0, 1); /* call it */
if (lua_isnil(L, -1)) {
*size = 0;
return NULL;
}
else if ((s = lua_tostring(L, -1)) != NULL) {
if (*mode != NULL) { /* first time? */
s = checkrights(L, *mode, s); /* check whether chunk format is allowed */
*mode = NULL; /* to avoid further checks */
if (stat->mode != NULL) { /* first time? */
s = checkrights(L, stat->mode, s); /* check mode */
stat->mode = NULL; /* to avoid further checks */
if (s) luaL_error(L, s);
}
lua_replace(L, 3); /* save string in a reserved stack slot */
return lua_tolstring(L, 3, size);
lua_replace(L, RESERVEDSLOT); /* save string in reserved slot */
return lua_tolstring(L, RESERVEDSLOT, size);
}
else {
luaL_error(L, "reader function must return a string");
@ -318,30 +334,51 @@ static const char *generic_reader (lua_State *L, void *ud, size_t *size) {
}
static int luaB_load (lua_State *L) {
static int luaB_load_aux (lua_State *L, int farg) {
int status;
const char *s = lua_tostring(L, 1);
const char *mode = luaL_optstring(L, 3, "bt");
Readstat stat;
const char *s = lua_tostring(L, farg);
stat.mode = luaL_optstring(L, farg + 2, "bt");
if (s != NULL) { /* loading a string? */
const char *chunkname = luaL_optstring(L, 2, s);
status = (checkrights(L, mode, s) != NULL)
|| luaL_loadbuffer(L, s, lua_objlen(L, 1), chunkname);
const char *chunkname = luaL_optstring(L, farg + 1, s);
status = (checkrights(L, stat.mode, s) != NULL)
|| luaL_loadbuffer(L, s, lua_objlen(L, farg), chunkname);
}
else { /* loading from a reader function */
const char *chunkname = luaL_optstring(L, 2, "=(load)");
luaL_checktype(L, 1, LUA_TFUNCTION);
lua_settop(L, 3); /* function, eventual name, plus one reserved slot */
status = lua_load(L, generic_reader, &mode, chunkname);
const char *chunkname = luaL_optstring(L, farg + 1, "=(load)");
luaL_checktype(L, farg, LUA_TFUNCTION);
stat.f = farg;
lua_settop(L, RESERVEDSLOT); /* create reserved slot */
status = lua_load(L, generic_reader, &stat, chunkname);
}
return load_aux(L, status);
}
static int luaB_load (lua_State *L) {
return luaB_load_aux(L, 1);
}
static int luaB_loadin (lua_State *L) {
int n;
luaL_checktype(L, 1, LUA_TTABLE);
n = luaB_load_aux(L, 2);
if (n == 1) { /* success? */
lua_pushvalue(L, 1); /* environment for loaded function */
lua_setfenv(L, -2);
}
return n;
}
static int luaB_loadstring (lua_State *L) {
lua_settop(L, 2);
lua_pushliteral(L, "tb");
return luaB_load(L); /* dostring(s, n) == load(s, n, "tb") */
}
/* }====================================================== */
static int dofilecont (lua_State *L) {
@ -481,6 +518,7 @@ static const luaL_Reg base_funcs[] = {
{"getmetatable", luaB_getmetatable},
{"loadfile", luaB_loadfile},
{"load", luaB_load},
{"loadin", luaB_loadin},
{"loadstring", luaB_loadstring},
{"next", luaB_next},
{"pcall", luaB_pcall},