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regex code refactor 

- declare API_TYPE_REGEX
- move error report code to a function
- move regex table check to a function
- add regex.source and regex.flags
- add regex:nametable()
- ensure stack size in regex:cmatch()
- fix wrong match indices
This commit is contained in:
takase1121 2021-07-30 17:52:21 +08:00
parent 135ad072bd
commit 09d6087df8
2 changed files with 142 additions and 56 deletions
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1
src/api/api.h
View File

@ -8,6 +8,7 @@
#define API_TYPE_FONT "Font"
#define API_TYPE_REPLACE "Replace"
#define API_TYPE_PROCESS "Process"
#define API_TYPE_REGEX "Regex"
void api_load_libs(lua_State *L);

181
src/api/regex.c
View File

@ -2,12 +2,50 @@
#define PCRE2_CODE_UNIT_WIDTH 8
#include <stdarg.h>
#include <string.h>
#include <pcre2.h>
// something similiar to luaL_checkudata() but for regex only
static pcre2_code* check_regex(lua_State* L, int arg) {
luaL_checktype(L, arg, LUA_TTABLE);
int hasmt = 0;
pcre2_code* re = NULL;
if (lua_getmetatable(L, arg)) {
luaL_getmetatable(L, API_TYPE_REGEX);
hasmt = lua_rawequal(L, -1, -2);
lua_pop(L, 2);
}
lua_rawgeti(L, arg, 1);
re = lua_touserdata(L, -1);
lua_pop(L, 1);
if (!hasmt || re == NULL)
luaL_argerror(L, arg, "invalid regex object");
return re;
}
static int pcre2_error(lua_State *L, int rc, const char *fmt, ...) {
va_list ap;
va_start(ap, fmt);
lua_pushvfstring(L, fmt, ap);
va_end(ap);
PCRE2_UCHAR err[256];
pcre2_get_error_message(rc, err, sizeof(err));
lua_pushstring(L, (const char *) err);
lua_concat(L, 2);
lua_error(L);
return 0;
}
static int f_pcre_gc(lua_State* L) {
lua_rawgeti(L, -1, 1);
pcre2_code* re = (pcre2_code*)lua_touserdata(L, -1);
pcre2_code* re = check_regex(L, 1);
if (re)
pcre2_code_free(re);
return 0;
@ -15,80 +53,121 @@ static int f_pcre_gc(lua_State* L) {
static int f_pcre_compile(lua_State *L) {
size_t len;
PCRE2_SIZE errorOffset;
int errorNumber;
int pattern = PCRE2_UTF;
const char* str = luaL_checklstring(L, 1, &len);
if (lua_gettop(L) > 1) {
const char* options = luaL_checkstring(L, 2);
if (strstr(options,"i"))
pattern |= PCRE2_CASELESS;
if (strstr(options,"m"))
pattern |= PCRE2_MULTILINE;
if (strstr(options,"s"))
pattern |= PCRE2_DOTALL;
}
int options = PCRE2_UTF;
const char* pattern = luaL_checklstring(L, 1, &len);
const char* optstr = luaL_optstring(L, 2, "");
if (strstr(optstr,"i"))
options |= PCRE2_CASELESS;
if (strstr(optstr,"m"))
options |= PCRE2_MULTILINE;
if (strstr(optstr,"s"))
options |= PCRE2_DOTALL;
int error;
PCRE2_SIZE error_offset;
pcre2_code* re = pcre2_compile(
(PCRE2_SPTR)str,
(PCRE2_SPTR)pattern,
len,
pattern,
&errorNumber,
&errorOffset,
options,
&error,
&error_offset,
NULL
);
if (re) {
if (re == NULL)
return pcre2_error(L, error, "regex compilation failed at %d: ", error_offset);
lua_newtable(L);
lua_pushlightuserdata(L, re);
luaL_setmetatable(L, API_TYPE_REGEX);
lua_pushlightuserdata(L, (void*) re);
lua_rawseti(L, -2, 1);
luaL_setmetatable(L, "regex");
lua_pushvalue(L, 1);
lua_setfield(L, -2, "source");
lua_pushstring(L, optstr);
lua_setfield(L, -2, "flags");
return 1;
}
PCRE2_UCHAR buffer[256];
pcre2_get_error_message(errorNumber, buffer, sizeof(buffer));
lua_pushnil(L);
char message[1024];
len = snprintf(message, sizeof(message), "regex compilation failed at offset %d: %s", (int)errorOffset, buffer);
lua_pushlstring(L, message, len);
return 2;
// get nametable (useful for named captures)
static int f_pcre_nametable(lua_State* L) {
pcre2_code* re = check_regex(L, 1);
int ret;
uint32_t namecount, entrysize;
PCRE2_SPTR nametable;
ret = pcre2_pattern_info(re, PCRE2_INFO_NAMETABLE, &nametable);
if (ret)
return pcre2_error(L, ret, "cannot get PCRE2_INFO_NAMETABLE: ");
pcre2_pattern_info(re, PCRE2_INFO_NAMECOUNT, &namecount);
pcre2_pattern_info(re, PCRE2_INFO_NAMEENTRYSIZE, &entrysize);
lua_createtable(L, namecount, 0);
for (uint32_t i = 0; i < namecount; i++) {
uint16_t index = (nametable[1] << 0) | (nametable[0] << 8);
nametable += 2;
lua_createtable(L, 0, 2);
lua_pushnumber(L, index);
lua_setfield(L, -2, "index");
lua_pushstring(L, (const char *) nametable);
lua_setfield(L, -2, "name");
lua_rawseti(L, -2, i + 1);
nametable += (entrysize - 2);
}
return 1;
}
// Takes string, compiled regex, returns list of indices of matched groups
// (including the whole match), if a match was found.
static int f_pcre_match(lua_State *L) {
size_t len, offset = 1, opts = 0;
luaL_checktype(L, 1, LUA_TTABLE);
size_t len, offset, options;
pcre2_code* re = check_regex(L, 1);
const char* str = luaL_checklstring(L, 2, &len);
if (lua_gettop(L) > 2)
offset = luaL_checknumber(L, 3);
if (lua_gettop(L) > 3)
opts = luaL_checknumber(L, 4);
lua_rawgeti(L, 1, 1);
pcre2_code* re = (pcre2_code*)lua_touserdata(L, -1);
offset = luaL_optnumber(L, 3, 1);
options = luaL_optnumber(L, 4, 0);
pcre2_match_data* md = pcre2_match_data_create_from_pattern(re, NULL);
int rc = pcre2_match(re, (PCRE2_SPTR)str, len, offset - 1, opts, md, NULL);
int rc = pcre2_match(re, (PCRE2_SPTR)str, len, offset - 1, options, md, NULL);
if (rc < 0) {
pcre2_match_data_free(md);
if (rc != PCRE2_ERROR_NOMATCH)
luaL_error(L, "regex matching error %d", rc);
if (rc != PCRE2_ERROR_NOMATCH) {
PCRE2_UCHAR buffer[256];
pcre2_get_error_message(rc, buffer, sizeof(buffer));
luaL_error(L, "regex matching error: %s", buffer);
}
return 0;
}
PCRE2_SIZE* ovector = pcre2_get_ovector_pointer(md);
if (ovector[0] > ovector[1]) {
pcre2_match_data_free(md);
/* We must guard against patterns such as /(?=.\K)/ that use \K in an
assertion to set the start of a match later than its end. In the editor,
we just detect this case and give up. */
luaL_error(L, "regex matching error: \\K was used in an assertion to "
" set the match start after its end");
pcre2_match_data_free(md);
return 0;
}
for (int i = 0; i < rc*2; i++)
lua_pushnumber(L, ovector[i]+1);
rc *= 2;
luaL_checkstack(L, rc, NULL);
for (int i = 0; i < rc; i++)
// for every even vector (the end of a pair), we do not increment by 1
lua_pushnumber(L, ovector[i] + (i + 1) % 2);
pcre2_match_data_free(md);
return rc*2;
return rc;
}
static const luaL_Reg lib[] = {
{ "nametable", f_pcre_nametable },
{ "compile", f_pcre_compile },
{ "cmatch", f_pcre_match },
{ "__gc", f_pcre_gc },
@ -96,22 +175,28 @@ static const luaL_Reg lib[] = {
};
int luaopen_regex(lua_State *L) {
luaL_newlib(L, lib);
lua_pushliteral(L, "regex");
lua_setfield(L, -2, "__name");
luaL_newmetatable(L, API_TYPE_REGEX);
luaL_setfuncs(L, lib, 0);
lua_pushvalue(L, -1);
lua_setfield(L, LUA_REGISTRYINDEX, "regex");
lua_setfield(L, -2, "__index");
lua_pushnumber(L, PCRE2_ANCHORED);
lua_setfield(L, -2, "ANCHORED");
lua_pushnumber(L, PCRE2_ANCHORED) ;
lua_setfield(L, -2, "ENDANCHORED");
lua_pushnumber(L, PCRE2_NOTBOL);
lua_setfield(L, -2, "NOTBOL");
lua_pushnumber(L, PCRE2_NOTEOL);
lua_setfield(L, -2, "NOTEOL");
lua_pushnumber(L, PCRE2_NOTEMPTY);
lua_setfield(L, -2, "NOTEMPTY");
lua_pushnumber(L, PCRE2_NOTEMPTY_ATSTART);
lua_setfield(L, -2, "NOTEMPTY_ATSTART");
return 1;
}