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git/grep.c
René Scharfe 252d560d21 grep: micro-optimize hit collection for AND nodes
In addition to returning if an expression matches a line,
match_expr_eval() updates the expression's hit flag if the parameter
collect_hits is set.  It never sets collect_hits for children of AND
nodes, though, so their hit flag will never be updated.  Because of
that we can return early if the first child didn't match, no matter
if collect_hits is set or not.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-03-07 11:34:53 -08:00

639 lines
14 KiB
C

#include "cache.h"
#include "grep.h"
#include "xdiff-interface.h"
void append_header_grep_pattern(struct grep_opt *opt, enum grep_header_field field, const char *pat)
{
struct grep_pat *p = xcalloc(1, sizeof(*p));
p->pattern = pat;
p->origin = "header";
p->no = 0;
p->token = GREP_PATTERN_HEAD;
p->field = field;
*opt->pattern_tail = p;
opt->pattern_tail = &p->next;
p->next = NULL;
}
void append_grep_pattern(struct grep_opt *opt, const char *pat,
const char *origin, int no, enum grep_pat_token t)
{
struct grep_pat *p = xcalloc(1, sizeof(*p));
p->pattern = pat;
p->origin = origin;
p->no = no;
p->token = t;
*opt->pattern_tail = p;
opt->pattern_tail = &p->next;
p->next = NULL;
}
static int is_fixed(const char *s)
{
while (*s && !is_regex_special(*s))
s++;
return !*s;
}
static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
{
int err;
if (opt->fixed || is_fixed(p->pattern))
p->fixed = 1;
if (opt->regflags & REG_ICASE)
p->fixed = 0;
if (p->fixed)
return;
err = regcomp(&p->regexp, p->pattern, opt->regflags);
if (err) {
char errbuf[1024];
char where[1024];
if (p->no)
sprintf(where, "In '%s' at %d, ",
p->origin, p->no);
else if (p->origin)
sprintf(where, "%s, ", p->origin);
else
where[0] = 0;
regerror(err, &p->regexp, errbuf, 1024);
regfree(&p->regexp);
die("%s'%s': %s", where, p->pattern, errbuf);
}
}
static struct grep_expr *compile_pattern_or(struct grep_pat **);
static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
{
struct grep_pat *p;
struct grep_expr *x;
p = *list;
switch (p->token) {
case GREP_PATTERN: /* atom */
case GREP_PATTERN_HEAD:
case GREP_PATTERN_BODY:
x = xcalloc(1, sizeof (struct grep_expr));
x->node = GREP_NODE_ATOM;
x->u.atom = p;
*list = p->next;
return x;
case GREP_OPEN_PAREN:
*list = p->next;
x = compile_pattern_or(list);
if (!x)
return NULL;
if (!*list || (*list)->token != GREP_CLOSE_PAREN)
die("unmatched parenthesis");
*list = (*list)->next;
return x;
default:
return NULL;
}
}
static struct grep_expr *compile_pattern_not(struct grep_pat **list)
{
struct grep_pat *p;
struct grep_expr *x;
p = *list;
switch (p->token) {
case GREP_NOT:
if (!p->next)
die("--not not followed by pattern expression");
*list = p->next;
x = xcalloc(1, sizeof (struct grep_expr));
x->node = GREP_NODE_NOT;
x->u.unary = compile_pattern_not(list);
if (!x->u.unary)
die("--not followed by non pattern expression");
return x;
default:
return compile_pattern_atom(list);
}
}
static struct grep_expr *compile_pattern_and(struct grep_pat **list)
{
struct grep_pat *p;
struct grep_expr *x, *y, *z;
x = compile_pattern_not(list);
p = *list;
if (p && p->token == GREP_AND) {
if (!p->next)
die("--and not followed by pattern expression");
*list = p->next;
y = compile_pattern_and(list);
if (!y)
die("--and not followed by pattern expression");
z = xcalloc(1, sizeof (struct grep_expr));
z->node = GREP_NODE_AND;
z->u.binary.left = x;
z->u.binary.right = y;
return z;
}
return x;
}
static struct grep_expr *compile_pattern_or(struct grep_pat **list)
{
struct grep_pat *p;
struct grep_expr *x, *y, *z;
x = compile_pattern_and(list);
p = *list;
if (x && p && p->token != GREP_CLOSE_PAREN) {
y = compile_pattern_or(list);
if (!y)
die("not a pattern expression %s", p->pattern);
z = xcalloc(1, sizeof (struct grep_expr));
z->node = GREP_NODE_OR;
z->u.binary.left = x;
z->u.binary.right = y;
return z;
}
return x;
}
static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
{
return compile_pattern_or(list);
}
void compile_grep_patterns(struct grep_opt *opt)
{
struct grep_pat *p;
if (opt->all_match)
opt->extended = 1;
for (p = opt->pattern_list; p; p = p->next) {
switch (p->token) {
case GREP_PATTERN: /* atom */
case GREP_PATTERN_HEAD:
case GREP_PATTERN_BODY:
compile_regexp(p, opt);
break;
default:
opt->extended = 1;
break;
}
}
if (!opt->extended)
return;
/* Then bundle them up in an expression.
* A classic recursive descent parser would do.
*/
p = opt->pattern_list;
opt->pattern_expression = compile_pattern_expr(&p);
if (p)
die("incomplete pattern expression: %s", p->pattern);
}
static void free_pattern_expr(struct grep_expr *x)
{
switch (x->node) {
case GREP_NODE_ATOM:
break;
case GREP_NODE_NOT:
free_pattern_expr(x->u.unary);
break;
case GREP_NODE_AND:
case GREP_NODE_OR:
free_pattern_expr(x->u.binary.left);
free_pattern_expr(x->u.binary.right);
break;
}
free(x);
}
void free_grep_patterns(struct grep_opt *opt)
{
struct grep_pat *p, *n;
for (p = opt->pattern_list; p; p = n) {
n = p->next;
switch (p->token) {
case GREP_PATTERN: /* atom */
case GREP_PATTERN_HEAD:
case GREP_PATTERN_BODY:
regfree(&p->regexp);
break;
default:
break;
}
free(p);
}
if (!opt->extended)
return;
free_pattern_expr(opt->pattern_expression);
}
static char *end_of_line(char *cp, unsigned long *left)
{
unsigned long l = *left;
while (l && *cp != '\n') {
l--;
cp++;
}
*left = l;
return cp;
}
static int word_char(char ch)
{
return isalnum(ch) || ch == '_';
}
static void show_line(struct grep_opt *opt, const char *bol, const char *eol,
const char *name, unsigned lno, char sign)
{
if (opt->null_following_name)
sign = '\0';
if (opt->pathname)
printf("%s%c", name, sign);
if (opt->linenum)
printf("%d%c", lno, sign);
printf("%.*s\n", (int)(eol-bol), bol);
}
static void show_name(struct grep_opt *opt, const char *name)
{
printf("%s%c", name, opt->null_following_name ? '\0' : '\n');
}
static int fixmatch(const char *pattern, char *line, regmatch_t *match)
{
char *hit = strstr(line, pattern);
if (!hit) {
match->rm_so = match->rm_eo = -1;
return REG_NOMATCH;
}
else {
match->rm_so = hit - line;
match->rm_eo = match->rm_so + strlen(pattern);
return 0;
}
}
static int strip_timestamp(char *bol, char **eol_p)
{
char *eol = *eol_p;
int ch;
while (bol < --eol) {
if (*eol != '>')
continue;
*eol_p = ++eol;
ch = *eol;
*eol = '\0';
return ch;
}
return 0;
}
static struct {
const char *field;
size_t len;
} header_field[] = {
{ "author ", 7 },
{ "committer ", 10 },
};
static int match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol, char *eol, enum grep_context ctx)
{
int hit = 0;
int saved_ch = 0;
regmatch_t pmatch[10];
if ((p->token != GREP_PATTERN) &&
((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
return 0;
if (p->token == GREP_PATTERN_HEAD) {
const char *field;
size_t len;
assert(p->field < ARRAY_SIZE(header_field));
field = header_field[p->field].field;
len = header_field[p->field].len;
if (strncmp(bol, field, len))
return 0;
bol += len;
saved_ch = strip_timestamp(bol, &eol);
}
again:
if (!p->fixed) {
regex_t *exp = &p->regexp;
hit = !regexec(exp, bol, ARRAY_SIZE(pmatch),
pmatch, 0);
}
else {
hit = !fixmatch(p->pattern, bol, pmatch);
}
if (hit && opt->word_regexp) {
if ((pmatch[0].rm_so < 0) ||
(eol - bol) <= pmatch[0].rm_so ||
(pmatch[0].rm_eo < 0) ||
(eol - bol) < pmatch[0].rm_eo)
die("regexp returned nonsense");
/* Match beginning must be either beginning of the
* line, or at word boundary (i.e. the last char must
* not be a word char). Similarly, match end must be
* either end of the line, or at word boundary
* (i.e. the next char must not be a word char).
*/
if ( ((pmatch[0].rm_so == 0) ||
!word_char(bol[pmatch[0].rm_so-1])) &&
((pmatch[0].rm_eo == (eol-bol)) ||
!word_char(bol[pmatch[0].rm_eo])) )
;
else
hit = 0;
if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
/* There could be more than one match on the
* line, and the first match might not be
* strict word match. But later ones could be!
* Forward to the next possible start, i.e. the
* next position following a non-word char.
*/
bol = pmatch[0].rm_so + bol + 1;
while (word_char(bol[-1]) && bol < eol)
bol++;
if (bol < eol)
goto again;
}
}
if (p->token == GREP_PATTERN_HEAD && saved_ch)
*eol = saved_ch;
return hit;
}
static int match_expr_eval(struct grep_opt *o,
struct grep_expr *x,
char *bol, char *eol,
enum grep_context ctx,
int collect_hits)
{
int h = 0;
switch (x->node) {
case GREP_NODE_ATOM:
h = match_one_pattern(o, x->u.atom, bol, eol, ctx);
break;
case GREP_NODE_NOT:
h = !match_expr_eval(o, x->u.unary, bol, eol, ctx, 0);
break;
case GREP_NODE_AND:
if (!match_expr_eval(o, x->u.binary.left, bol, eol, ctx, 0))
return 0;
h = match_expr_eval(o, x->u.binary.right, bol, eol, ctx, 0);
break;
case GREP_NODE_OR:
if (!collect_hits)
return (match_expr_eval(o, x->u.binary.left,
bol, eol, ctx, 0) ||
match_expr_eval(o, x->u.binary.right,
bol, eol, ctx, 0));
h = match_expr_eval(o, x->u.binary.left, bol, eol, ctx, 0);
x->u.binary.left->hit |= h;
h |= match_expr_eval(o, x->u.binary.right, bol, eol, ctx, 1);
break;
default:
die("Unexpected node type (internal error) %d", x->node);
}
if (collect_hits)
x->hit |= h;
return h;
}
static int match_expr(struct grep_opt *opt, char *bol, char *eol,
enum grep_context ctx, int collect_hits)
{
struct grep_expr *x = opt->pattern_expression;
return match_expr_eval(opt, x, bol, eol, ctx, collect_hits);
}
static int match_line(struct grep_opt *opt, char *bol, char *eol,
enum grep_context ctx, int collect_hits)
{
struct grep_pat *p;
if (opt->extended)
return match_expr(opt, bol, eol, ctx, collect_hits);
/* we do not call with collect_hits without being extended */
for (p = opt->pattern_list; p; p = p->next) {
if (match_one_pattern(opt, p, bol, eol, ctx))
return 1;
}
return 0;
}
static int grep_buffer_1(struct grep_opt *opt, const char *name,
char *buf, unsigned long size, int collect_hits)
{
char *bol = buf;
unsigned long left = size;
unsigned lno = 1;
struct pre_context_line {
char *bol;
char *eol;
} *prev = NULL, *pcl;
unsigned last_hit = 0;
unsigned last_shown = 0;
int binary_match_only = 0;
const char *hunk_mark = "";
unsigned count = 0;
enum grep_context ctx = GREP_CONTEXT_HEAD;
if (buffer_is_binary(buf, size)) {
switch (opt->binary) {
case GREP_BINARY_DEFAULT:
binary_match_only = 1;
break;
case GREP_BINARY_NOMATCH:
return 0; /* Assume unmatch */
break;
default:
break;
}
}
if (opt->pre_context)
prev = xcalloc(opt->pre_context, sizeof(*prev));
if (opt->pre_context || opt->post_context)
hunk_mark = "--\n";
while (left) {
char *eol, ch;
int hit;
eol = end_of_line(bol, &left);
ch = *eol;
*eol = 0;
if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
ctx = GREP_CONTEXT_BODY;
hit = match_line(opt, bol, eol, ctx, collect_hits);
*eol = ch;
if (collect_hits)
goto next_line;
/* "grep -v -e foo -e bla" should list lines
* that do not have either, so inversion should
* be done outside.
*/
if (opt->invert)
hit = !hit;
if (opt->unmatch_name_only) {
if (hit)
return 0;
goto next_line;
}
if (hit) {
count++;
if (opt->status_only)
return 1;
if (binary_match_only) {
printf("Binary file %s matches\n", name);
return 1;
}
if (opt->name_only) {
show_name(opt, name);
return 1;
}
/* Hit at this line. If we haven't shown the
* pre-context lines, we would need to show them.
* When asked to do "count", this still show
* the context which is nonsense, but the user
* deserves to get that ;-).
*/
if (opt->pre_context) {
unsigned from;
if (opt->pre_context < lno)
from = lno - opt->pre_context;
else
from = 1;
if (from <= last_shown)
from = last_shown + 1;
if (last_shown && from != last_shown + 1)
fputs(hunk_mark, stdout);
while (from < lno) {
pcl = &prev[lno-from-1];
show_line(opt, pcl->bol, pcl->eol,
name, from, '-');
from++;
}
last_shown = lno-1;
}
if (last_shown && lno != last_shown + 1)
fputs(hunk_mark, stdout);
if (!opt->count)
show_line(opt, bol, eol, name, lno, ':');
last_shown = last_hit = lno;
}
else if (last_hit &&
lno <= last_hit + opt->post_context) {
/* If the last hit is within the post context,
* we need to show this line.
*/
if (last_shown && lno != last_shown + 1)
fputs(hunk_mark, stdout);
show_line(opt, bol, eol, name, lno, '-');
last_shown = lno;
}
if (opt->pre_context) {
memmove(prev+1, prev,
(opt->pre_context-1) * sizeof(*prev));
prev->bol = bol;
prev->eol = eol;
}
next_line:
bol = eol + 1;
if (!left)
break;
left--;
lno++;
}
free(prev);
if (collect_hits)
return 0;
if (opt->status_only)
return 0;
if (opt->unmatch_name_only) {
/* We did not see any hit, so we want to show this */
show_name(opt, name);
return 1;
}
/* NEEDSWORK:
* The real "grep -c foo *.c" gives many "bar.c:0" lines,
* which feels mostly useless but sometimes useful. Maybe
* make it another option? For now suppress them.
*/
if (opt->count && count)
printf("%s%c%u\n", name,
opt->null_following_name ? '\0' : ':', count);
return !!last_hit;
}
static void clr_hit_marker(struct grep_expr *x)
{
/* All-hit markers are meaningful only at the very top level
* OR node.
*/
while (1) {
x->hit = 0;
if (x->node != GREP_NODE_OR)
return;
x->u.binary.left->hit = 0;
x = x->u.binary.right;
}
}
static int chk_hit_marker(struct grep_expr *x)
{
/* Top level nodes have hit markers. See if they all are hits */
while (1) {
if (x->node != GREP_NODE_OR)
return x->hit;
if (!x->u.binary.left->hit)
return 0;
x = x->u.binary.right;
}
}
int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
{
/*
* we do not have to do the two-pass grep when we do not check
* buffer-wide "all-match".
*/
if (!opt->all_match)
return grep_buffer_1(opt, name, buf, size, 0);
/* Otherwise the toplevel "or" terms hit a bit differently.
* We first clear hit markers from them.
*/
clr_hit_marker(opt->pattern_expression);
grep_buffer_1(opt, name, buf, size, 1);
if (!chk_hit_marker(opt->pattern_expression))
return 0;
return grep_buffer_1(opt, name, buf, size, 0);
}