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git/userdiff.c
Paolo Bonzini 959e2e64a5 avoid exponential regex match for java and objc function names
In the old regex

^[ \t]*(([ \t]*[A-Za-z_][A-Za-z_0-9]*){2,}[ \t]*\([^;]*)$
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

you can backtrack arbitrarily from [A-Za-z_0-9]* into [A-Za-z_], thus
causing an exponential number of backtracks.  Ironically it also causes
the regex not to work as intended; for example "catch" can match the
underlined part of the regex, the first repetition matching "c" and
the second matching "atch".

The replacement regex avoids this problem, because it makes sure that
at least a space/tab is eaten on each repetition.  In other words,
a suffix of a repetition can never be a prefix of the next repetition.

Signed-off-by: Paolo Bonzini <bonzini@gnu.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-06-18 09:52:10 -07:00

216 lines
6 KiB
C

#include "userdiff.h"
#include "cache.h"
#include "attr.h"
static struct userdiff_driver *drivers;
static int ndrivers;
static int drivers_alloc;
#define PATTERNS(name, pattern, word_regex) \
{ name, NULL, -1, { pattern, REG_EXTENDED }, word_regex }
static struct userdiff_driver builtin_drivers[] = {
PATTERNS("html", "^[ \t]*(<[Hh][1-6][ \t].*>.*)$",
"[^<>= \t]+|[^[:space:]]|[\x80-\xff]+"),
PATTERNS("java",
"!^[ \t]*(catch|do|for|if|instanceof|new|return|switch|throw|while)\n"
"^[ \t]*(([A-Za-z_][A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$",
/* -- */
"[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
"|[-+*/<>%&^|=!]="
"|--|\\+\\+|<<=?|>>>?=?|&&|\\|\\|"
"|[^[:space:]]|[\x80-\xff]+"),
PATTERNS("objc",
/* Negate C statements that can look like functions */
"!^[ \t]*(do|for|if|else|return|switch|while)\n"
/* Objective-C methods */
"^[ \t]*([-+][ \t]*\\([ \t]*[A-Za-z_][A-Za-z_0-9* \t]*\\)[ \t]*[A-Za-z_].*)$\n"
/* C functions */
"^[ \t]*(([A-Za-z_][A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$\n"
/* Objective-C class/protocol definitions */
"^(@(implementation|interface|protocol)[ \t].*)$",
/* -- */
"[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
"|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"
"|[^[:space:]]|[\x80-\xff]+"),
PATTERNS("pascal",
"^((procedure|function|constructor|destructor|interface|"
"implementation|initialization|finalization)[ \t]*.*)$"
"\n"
"^(.*=[ \t]*(class|record).*)$",
/* -- */
"[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+"
"|<>|<=|>=|:=|\\.\\."
"|[^[:space:]]|[\x80-\xff]+"),
PATTERNS("php", "^[\t ]*((function|class).*)",
/* -- */
"[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+"
"|[-+*/<>%&^|=!.]=|--|\\+\\+|<<=?|>>=?|===|&&|\\|\\||::|->"
"|[^[:space:]]|[\x80-\xff]+"),
PATTERNS("python", "^[ \t]*((class|def)[ \t].*)$",
/* -- */
"[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+[jJlL]?|0[xX]?[0-9a-fA-F]+[lL]?"
"|[-+*/<>%&^|=!]=|//=?|<<=?|>>=?|\\*\\*=?"
"|[^[:space:]|[\x80-\xff]+"),
/* -- */
PATTERNS("ruby", "^[ \t]*((class|module|def)[ \t].*)$",
/* -- */
"(@|@@|\\$)?[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+|\\?(\\\\C-)?(\\\\M-)?."
"|//=?|[-+*/<>%&^|=!]=|<<=?|>>=?|===|\\.{1,3}|::|[!=]~"
"|[^[:space:]|[\x80-\xff]+"),
PATTERNS("bibtex", "(@[a-zA-Z]{1,}[ \t]*\\{{0,1}[ \t]*[^ \t\"@',\\#}{~%]*).*$",
"[={}\"]|[^={}\" \t]+"),
PATTERNS("tex", "^(\\\\((sub)*section|chapter|part)\\*{0,1}\\{.*)$",
"\\\\[a-zA-Z@]+|\\\\.|[a-zA-Z0-9\x80-\xff]+|[^[:space:]]"),
PATTERNS("cpp",
/* Jump targets or access declarations */
"!^[ \t]*[A-Za-z_][A-Za-z_0-9]*:.*$\n"
/* C/++ functions/methods at top level */
"^([A-Za-z_][A-Za-z_0-9]*([ \t]+[A-Za-z_][A-Za-z_0-9]*([ \t]*::[ \t]*[^[:space:]]+)?){1,}[ \t]*\\([^;]*)$\n"
/* compound type at top level */
"^((struct|class|enum)[^;]*)$",
/* -- */
"[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
"|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"
"|[^[:space:]]|[\x80-\xff]+"),
{ "default", NULL, -1, { NULL, 0 } },
};
#undef PATTERNS
static struct userdiff_driver driver_true = {
"diff=true",
NULL,
0,
{ NULL, 0 }
};
static struct userdiff_driver driver_false = {
"!diff",
NULL,
1,
{ NULL, 0 }
};
static struct userdiff_driver *userdiff_find_by_namelen(const char *k, int len)
{
int i;
for (i = 0; i < ndrivers; i++) {
struct userdiff_driver *drv = drivers + i;
if (!strncmp(drv->name, k, len) && !drv->name[len])
return drv;
}
for (i = 0; i < ARRAY_SIZE(builtin_drivers); i++) {
struct userdiff_driver *drv = builtin_drivers + i;
if (!strncmp(drv->name, k, len) && !drv->name[len])
return drv;
}
return NULL;
}
static struct userdiff_driver *parse_driver(const char *var,
const char *value, const char *type)
{
struct userdiff_driver *drv;
const char *dot;
const char *name;
int namelen;
if (prefixcmp(var, "diff."))
return NULL;
dot = strrchr(var, '.');
if (dot == var + 4)
return NULL;
if (strcmp(type, dot+1))
return NULL;
name = var + 5;
namelen = dot - name;
drv = userdiff_find_by_namelen(name, namelen);
if (!drv) {
ALLOC_GROW(drivers, ndrivers+1, drivers_alloc);
drv = &drivers[ndrivers++];
memset(drv, 0, sizeof(*drv));
drv->name = xmemdupz(name, namelen);
drv->binary = -1;
}
return drv;
}
static int parse_funcname(struct userdiff_funcname *f, const char *k,
const char *v, int cflags)
{
if (git_config_string(&f->pattern, k, v) < 0)
return -1;
f->cflags = cflags;
return 1;
}
static int parse_string(const char **d, const char *k, const char *v)
{
if (git_config_string(d, k, v) < 0)
return -1;
return 1;
}
static int parse_tristate(int *b, const char *k, const char *v)
{
if (v && !strcasecmp(v, "auto"))
*b = -1;
else
*b = git_config_bool(k, v);
return 1;
}
int userdiff_config(const char *k, const char *v)
{
struct userdiff_driver *drv;
if ((drv = parse_driver(k, v, "funcname")))
return parse_funcname(&drv->funcname, k, v, 0);
if ((drv = parse_driver(k, v, "xfuncname")))
return parse_funcname(&drv->funcname, k, v, REG_EXTENDED);
if ((drv = parse_driver(k, v, "binary")))
return parse_tristate(&drv->binary, k, v);
if ((drv = parse_driver(k, v, "command")))
return parse_string(&drv->external, k, v);
if ((drv = parse_driver(k, v, "textconv")))
return parse_string(&drv->textconv, k, v);
if ((drv = parse_driver(k, v, "wordregex")))
return parse_string(&drv->word_regex, k, v);
return 0;
}
struct userdiff_driver *userdiff_find_by_name(const char *name) {
int len = strlen(name);
return userdiff_find_by_namelen(name, len);
}
struct userdiff_driver *userdiff_find_by_path(const char *path)
{
static struct git_attr *attr;
struct git_attr_check check;
if (!attr)
attr = git_attr("diff", 4);
check.attr = attr;
if (!path)
return NULL;
if (git_checkattr(path, 1, &check))
return NULL;
if (ATTR_TRUE(check.value))
return &driver_true;
if (ATTR_FALSE(check.value))
return &driver_false;
if (ATTR_UNSET(check.value))
return NULL;
return userdiff_find_by_name(check.value);
}