[thirdparty/git.git] / grep.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;
	if (!p)
		return NULL;
	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 (!*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;
	if (!p)
		return NULL;
	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;

	if (!x)
		die("Not a valid grep expression");
	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 (!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);
		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);
}
Commit	Line	Data
83b5d2f5	1	#include "cache.h"
83b5d2f5	2	#include "grep.h"
6bfce93e	3	#include "xdiff-interface.h"
83b5d2f5	4
a4d7d2c6 JH	5	void append_header_grep_pattern(struct grep_opt opt, enum grep_header_field field, const char pat)
	6	{
	7	struct grep_pat p = xcalloc(1, sizeof(p));
	8	p->pattern = pat;
	9	p->origin = "header";
	10	p->no = 0;
	11	p->token = GREP_PATTERN_HEAD;
	12	p->field = field;
	13	*opt->pattern_tail = p;
	14	opt->pattern_tail = &p->next;
	15	p->next = NULL;
	16	}
	17
83b5d2f5 JH	18	void append_grep_pattern(struct grep_opt opt, const char pat,
	19	const char *origin, int no, enum grep_pat_token t)
	20	{
	21	struct grep_pat p = xcalloc(1, sizeof(p));
	22	p->pattern = pat;
	23	p->origin = origin;
	24	p->no = no;
	25	p->token = t;
	26	*opt->pattern_tail = p;
	27	opt->pattern_tail = &p->next;
	28	p->next = NULL;
	29	}
	30
c822255c RS	31	static int is_fixed(const char *s)
c822255c RS	32	{
f9b7cce6	33	while (s && !is_regex_special(s))
c822255c RS	34	s++;
	35	return !*s;
	36	}
	37
83b5d2f5 JH	38	static void compile_regexp(struct grep_pat p, struct grep_opt opt)
83b5d2f5 JH	39	{
c822255c RS	40	int err;
	41
	42	if (opt->fixed \|\| is_fixed(p->pattern))
	43	p->fixed = 1;
	44	if (opt->regflags & REG_ICASE)
	45	p->fixed = 0;
	46	if (p->fixed)
	47	return;
	48
	49	err = regcomp(&p->regexp, p->pattern, opt->regflags);
83b5d2f5 JH	50	if (err) {
	51	char errbuf[1024];
	52	char where[1024];
	53	if (p->no)
	54	sprintf(where, "In '%s' at %d, ",
	55	p->origin, p->no);
	56	else if (p->origin)
	57	sprintf(where, "%s, ", p->origin);
	58	else
	59	where[0] = 0;
	60	regerror(err, &p->regexp, errbuf, 1024);
	61	regfree(&p->regexp);
	62	die("%s'%s': %s", where, p->pattern, errbuf);
	63	}
	64	}
	65
0ab7befa	66	static struct grep_expr compile_pattern_or(struct grep_pat *);
83b5d2f5 JH	67	static struct grep_expr compile_pattern_atom(struct grep_pat *list)
	68	{
	69	struct grep_pat *p;
	70	struct grep_expr *x;
	71
	72	p = *list;
c922b01f LT	73	if (!p)
c922b01f LT	74	return NULL;
83b5d2f5 JH	75	switch (p->token) {
83b5d2f5 JH	76	case GREP_PATTERN: /* atom */
480c1ca6 JH	77	case GREP_PATTERN_HEAD:
480c1ca6 JH	78	case GREP_PATTERN_BODY:
83b5d2f5 JH	79	x = xcalloc(1, sizeof (struct grep_expr));
	80	x->node = GREP_NODE_ATOM;
	81	x->u.atom = p;
	82	*list = p->next;
	83	return x;
	84	case GREP_OPEN_PAREN:
	85	*list = p->next;
0ab7befa	86	x = compile_pattern_or(list);
83b5d2f5 JH	87	if (!list \|\| (list)->token != GREP_CLOSE_PAREN)
	88	die("unmatched parenthesis");
	89	list = (list)->next;
	90	return x;
	91	default:
	92	return NULL;
	93	}
	94	}
	95
	96	static struct grep_expr compile_pattern_not(struct grep_pat *list)
	97	{
	98	struct grep_pat *p;
	99	struct grep_expr *x;
	100
	101	p = *list;
c922b01f LT	102	if (!p)
c922b01f LT	103	return NULL;
83b5d2f5 JH	104	switch (p->token) {
	105	case GREP_NOT:
	106	if (!p->next)
	107	die("--not not followed by pattern expression");
	108	*list = p->next;
	109	x = xcalloc(1, sizeof (struct grep_expr));
	110	x->node = GREP_NODE_NOT;
	111	x->u.unary = compile_pattern_not(list);
	112	if (!x->u.unary)
	113	die("--not followed by non pattern expression");
	114	return x;
	115	default:
	116	return compile_pattern_atom(list);
	117	}
	118	}
	119
	120	static struct grep_expr compile_pattern_and(struct grep_pat *list)
	121	{
	122	struct grep_pat *p;
	123	struct grep_expr x, y, *z;
	124
	125	x = compile_pattern_not(list);
	126	p = *list;
	127	if (p && p->token == GREP_AND) {
	128	if (!p->next)
	129	die("--and not followed by pattern expression");
	130	*list = p->next;
	131	y = compile_pattern_and(list);
	132	if (!y)
	133	die("--and not followed by pattern expression");
	134	z = xcalloc(1, sizeof (struct grep_expr));
	135	z->node = GREP_NODE_AND;
	136	z->u.binary.left = x;
	137	z->u.binary.right = y;
	138	return z;
	139	}
	140	return x;
	141	}
	142
	143	static struct grep_expr compile_pattern_or(struct grep_pat *list)
	144	{
	145	struct grep_pat *p;
	146	struct grep_expr x, y, *z;
	147
	148	x = compile_pattern_and(list);
	149	p = *list;
	150	if (x && p && p->token != GREP_CLOSE_PAREN) {
	151	y = compile_pattern_or(list);
	152	if (!y)
	153	die("not a pattern expression %s", p->pattern);
	154	z = xcalloc(1, sizeof (struct grep_expr));
	155	z->node = GREP_NODE_OR;
	156	z->u.binary.left = x;
	157	z->u.binary.right = y;
	158	return z;
	159	}
	160	return x;
	161	}
	162
	163	static struct grep_expr compile_pattern_expr(struct grep_pat *list)
	164	{
	165	return compile_pattern_or(list);
	166	}
	167
168	void compile_grep_patterns(struct grep_opt *opt)
169	{
170	struct grep_pat *p;
171
0ab7befa JH	172	if (opt->all_match)
	173	opt->extended = 1;
	174
83b5d2f5	175	for (p = opt->pattern_list; p; p = p->next) {
480c1ca6 JH	176	switch (p->token) {
	177	case GREP_PATTERN: /* atom */
	178	case GREP_PATTERN_HEAD:
	179	case GREP_PATTERN_BODY:
c822255c	180	compile_regexp(p, opt);
480c1ca6 JH	181	break;
480c1ca6 JH	182	default:
83b5d2f5	183	opt->extended = 1;
480c1ca6 JH	184	break;
480c1ca6 JH	185	}
83b5d2f5 JH	186	}
	187
	188	if (!opt->extended)
	189	return;
	190
	191	/* Then bundle them up in an expression.
	192	* A classic recursive descent parser would do.
	193	*/
	194	p = opt->pattern_list;
	195	opt->pattern_expression = compile_pattern_expr(&p);
	196	if (p)
	197	die("incomplete pattern expression: %s", p->pattern);
	198	}
	199
b48fb5b6 JH	200	static void free_pattern_expr(struct grep_expr *x)
	201	{
	202	switch (x->node) {
	203	case GREP_NODE_ATOM:
	204	break;
	205	case GREP_NODE_NOT:
	206	free_pattern_expr(x->u.unary);
	207	break;
	208	case GREP_NODE_AND:
	209	case GREP_NODE_OR:
	210	free_pattern_expr(x->u.binary.left);
	211	free_pattern_expr(x->u.binary.right);
	212	break;
	213	}
	214	free(x);
	215	}
	216
	217	void free_grep_patterns(struct grep_opt *opt)
	218	{
	219	struct grep_pat p, n;
	220
	221	for (p = opt->pattern_list; p; p = n) {
	222	n = p->next;
	223	switch (p->token) {
	224	case GREP_PATTERN: /* atom */
	225	case GREP_PATTERN_HEAD:
	226	case GREP_PATTERN_BODY:
	227	regfree(&p->regexp);
	228	break;
	229	default:
	230	break;
	231	}
	232	free(p);
	233	}
	234
	235	if (!opt->extended)
	236	return;
	237	free_pattern_expr(opt->pattern_expression);
	238	}
	239
83b5d2f5 JH	240	static char end_of_line(char cp, unsigned long *left)
	241	{
	242	unsigned long l = *left;
	243	while (l && *cp != '\n') {
	244	l--;
	245	cp++;
	246	}
	247	*left = l;
	248	return cp;
	249	}
	250
	251	static int word_char(char ch)
	252	{
	253	return isalnum(ch) \|\| ch == '_';
	254	}
	255
	256	static void show_line(struct grep_opt opt, const char bol, const char *eol,
	257	const char *name, unsigned lno, char sign)
	258	{
83caecca RZ	259	if (opt->null_following_name)
83caecca RZ	260	sign = '\0';
83b5d2f5 JH	261	if (opt->pathname)
	262	printf("%s%c", name, sign);
	263	if (opt->linenum)
	264	printf("%d%c", lno, sign);
	265	printf("%.*s\n", (int)(eol-bol), bol);
	266	}
	267
83caecca RZ	268	static void show_name(struct grep_opt opt, const char name)
	269	{
	270	printf("%s%c", name, opt->null_following_name ? '\0' : '\n');
	271	}
	272
83b5d2f5 JH	273	static int fixmatch(const char pattern, char line, regmatch_t *match)
	274	{
	275	char *hit = strstr(line, pattern);
	276	if (!hit) {
	277	match->rm_so = match->rm_eo = -1;
	278	return REG_NOMATCH;
	279	}
	280	else {
	281	match->rm_so = hit - line;
	282	match->rm_eo = match->rm_so + strlen(pattern);
	283	return 0;
	284	}
	285	}
	286
a4d7d2c6 JH	287	static int strip_timestamp(char bol, char *eol_p)
	288	{
	289	char eol = eol_p;
	290	int ch;
	291
	292	while (bol < --eol) {
	293	if (*eol != '>')
	294	continue;
	295	*eol_p = ++eol;
	296	ch = *eol;
	297	*eol = '\0';
	298	return ch;
	299	}
	300	return 0;
	301	}
	302
	303	static struct {
	304	const char *field;
	305	size_t len;
	306	} header_field[] = {
	307	{ "author ", 7 },
	308	{ "committer ", 10 },
	309	};
	310
480c1ca6	311	static int match_one_pattern(struct grep_opt opt, struct grep_pat p, char bol, char eol, enum grep_context ctx)
83b5d2f5 JH	312	{
83b5d2f5 JH	313	int hit = 0;
a4d7d2c6	314	int saved_ch = 0;
83b5d2f5 JH	315	regmatch_t pmatch[10];
83b5d2f5 JH	316
480c1ca6 JH	317	if ((p->token != GREP_PATTERN) &&
	318	((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
	319	return 0;
	320
a4d7d2c6 JH	321	if (p->token == GREP_PATTERN_HEAD) {
	322	const char *field;
	323	size_t len;
	324	assert(p->field < ARRAY_SIZE(header_field));
	325	field = header_field[p->field].field;
	326	len = header_field[p->field].len;
	327	if (strncmp(bol, field, len))
	328	return 0;
	329	bol += len;
	330	saved_ch = strip_timestamp(bol, &eol);
	331	}
	332
83b5d2f5	333	again:
c822255c	334	if (!p->fixed) {
83b5d2f5 JH	335	regex_t *exp = &p->regexp;
	336	hit = !regexec(exp, bol, ARRAY_SIZE(pmatch),
	337	pmatch, 0);
	338	}
	339	else {
	340	hit = !fixmatch(p->pattern, bol, pmatch);
	341	}
	342
	343	if (hit && opt->word_regexp) {
	344	if ((pmatch[0].rm_so < 0) \|\|
	345	(eol - bol) <= pmatch[0].rm_so \|\|
	346	(pmatch[0].rm_eo < 0) \|\|
	347	(eol - bol) < pmatch[0].rm_eo)
	348	die("regexp returned nonsense");
	349
	350	/* Match beginning must be either beginning of the
	351	* line, or at word boundary (i.e. the last char must
	352	* not be a word char). Similarly, match end must be
	353	* either end of the line, or at word boundary
	354	* (i.e. the next char must not be a word char).
	355	*/
fb62eb7f	356	if ( ((pmatch[0].rm_so == 0) \|\|
83b5d2f5 JH	357	!word_char(bol[pmatch[0].rm_so-1])) &&
	358	((pmatch[0].rm_eo == (eol-bol)) \|\|
	359	!word_char(bol[pmatch[0].rm_eo])) )
	360	;
	361	else
	362	hit = 0;
	363
	364	if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
	365	/* There could be more than one match on the
	366	* line, and the first match might not be
	367	* strict word match. But later ones could be!
fb62eb7f RS	368	* Forward to the next possible start, i.e. the
fb62eb7f RS	369	* next position following a non-word char.
83b5d2f5 JH	370	*/
83b5d2f5 JH	371	bol = pmatch[0].rm_so + bol + 1;
fb62eb7f RS	372	while (word_char(bol[-1]) && bol < eol)
	373	bol++;
	374	if (bol < eol)
	375	goto again;
83b5d2f5 JH	376	}
83b5d2f5 JH	377	}
a4d7d2c6 JH	378	if (p->token == GREP_PATTERN_HEAD && saved_ch)
a4d7d2c6 JH	379	*eol = saved_ch;
83b5d2f5 JH	380	return hit;
	381	}
	382
0ab7befa	383	static int match_expr_eval(struct grep_opt *o,
83b5d2f5	384	struct grep_expr *x,
480c1ca6	385	char bol, char eol,
0ab7befa JH	386	enum grep_context ctx,
0ab7befa JH	387	int collect_hits)
83b5d2f5	388	{
0ab7befa JH	389	int h = 0;
0ab7befa JH	390
c922b01f LT	391	if (!x)
c922b01f LT	392	die("Not a valid grep expression");
83b5d2f5 JH	393	switch (x->node) {
83b5d2f5 JH	394	case GREP_NODE_ATOM:
0ab7befa	395	h = match_one_pattern(o, x->u.atom, bol, eol, ctx);
83b5d2f5 JH	396	break;
83b5d2f5 JH	397	case GREP_NODE_NOT:
0ab7befa JH	398	h = !match_expr_eval(o, x->u.unary, bol, eol, ctx, 0);
0ab7befa JH	399	break;
83b5d2f5	400	case GREP_NODE_AND:
0ab7befa JH	401	if (!collect_hits)
	402	return (match_expr_eval(o, x->u.binary.left,
	403	bol, eol, ctx, 0) &&
	404	match_expr_eval(o, x->u.binary.right,
	405	bol, eol, ctx, 0));
	406	h = match_expr_eval(o, x->u.binary.left, bol, eol, ctx, 0);
	407	h &= match_expr_eval(o, x->u.binary.right, bol, eol, ctx, 0);
	408	break;
83b5d2f5	409	case GREP_NODE_OR:
0ab7befa JH	410	if (!collect_hits)
	411	return (match_expr_eval(o, x->u.binary.left,
	412	bol, eol, ctx, 0) \|\|
	413	match_expr_eval(o, x->u.binary.right,
	414	bol, eol, ctx, 0));
	415	h = match_expr_eval(o, x->u.binary.left, bol, eol, ctx, 0);
	416	x->u.binary.left->hit \|= h;
	417	h \|= match_expr_eval(o, x->u.binary.right, bol, eol, ctx, 1);
	418	break;
	419	default:
d7530708	420	die("Unexpected node type (internal error) %d", x->node);
83b5d2f5	421	}
0ab7befa JH	422	if (collect_hits)
	423	x->hit \|= h;
	424	return h;
83b5d2f5 JH	425	}
83b5d2f5 JH	426
480c1ca6	427	static int match_expr(struct grep_opt opt, char bol, char *eol,
0ab7befa	428	enum grep_context ctx, int collect_hits)
83b5d2f5 JH	429	{
83b5d2f5 JH	430	struct grep_expr *x = opt->pattern_expression;
0ab7befa	431	return match_expr_eval(opt, x, bol, eol, ctx, collect_hits);
83b5d2f5 JH	432	}
83b5d2f5 JH	433
480c1ca6	434	static int match_line(struct grep_opt opt, char bol, char *eol,
0ab7befa	435	enum grep_context ctx, int collect_hits)
83b5d2f5 JH	436	{
	437	struct grep_pat *p;
	438	if (opt->extended)
0ab7befa JH	439	return match_expr(opt, bol, eol, ctx, collect_hits);
	440
	441	/* we do not call with collect_hits without being extended */
83b5d2f5	442	for (p = opt->pattern_list; p; p = p->next) {
480c1ca6	443	if (match_one_pattern(opt, p, bol, eol, ctx))
83b5d2f5 JH	444	return 1;
	445	}
	446	return 0;
	447	}
	448
0ab7befa JH	449	static int grep_buffer_1(struct grep_opt opt, const char name,
0ab7befa JH	450	char *buf, unsigned long size, int collect_hits)
83b5d2f5 JH	451	{
	452	char *bol = buf;
	453	unsigned long left = size;
	454	unsigned lno = 1;
	455	struct pre_context_line {
	456	char *bol;
	457	char *eol;
	458	} prev = NULL, pcl;
	459	unsigned last_hit = 0;
	460	unsigned last_shown = 0;
	461	int binary_match_only = 0;
	462	const char *hunk_mark = "";
	463	unsigned count = 0;
480c1ca6	464	enum grep_context ctx = GREP_CONTEXT_HEAD;
83b5d2f5 JH	465
	466	if (buffer_is_binary(buf, size)) {
	467	switch (opt->binary) {
	468	case GREP_BINARY_DEFAULT:
	469	binary_match_only = 1;
	470	break;
	471	case GREP_BINARY_NOMATCH:
	472	return 0; /* Assume unmatch */
	473	break;
	474	default:
	475	break;
	476	}
	477	}
	478
	479	if (opt->pre_context)
	480	prev = xcalloc(opt->pre_context, sizeof(*prev));
	481	if (opt->pre_context \|\| opt->post_context)
	482	hunk_mark = "--\n";
	483
	484	while (left) {
	485	char *eol, ch;
0ab7befa	486	int hit;
83b5d2f5 JH	487
	488	eol = end_of_line(bol, &left);
	489	ch = *eol;
	490	*eol = 0;
	491
480c1ca6 JH	492	if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
	493	ctx = GREP_CONTEXT_BODY;
	494
0ab7befa	495	hit = match_line(opt, bol, eol, ctx, collect_hits);
83b5d2f5 JH	496	*eol = ch;
83b5d2f5 JH	497
0ab7befa JH	498	if (collect_hits)
	499	goto next_line;
	500
83b5d2f5 JH	501	/* "grep -v -e foo -e bla" should list lines
	502	* that do not have either, so inversion should
	503	* be done outside.
	504	*/
	505	if (opt->invert)
	506	hit = !hit;
	507	if (opt->unmatch_name_only) {
	508	if (hit)
	509	return 0;
	510	goto next_line;
	511	}
	512	if (hit) {
	513	count++;
	514	if (opt->status_only)
	515	return 1;
	516	if (binary_match_only) {
	517	printf("Binary file %s matches\n", name);
	518	return 1;
	519	}
	520	if (opt->name_only) {
83caecca	521	show_name(opt, name);
83b5d2f5 JH	522	return 1;
	523	}
	524	/* Hit at this line. If we haven't shown the
	525	* pre-context lines, we would need to show them.
	526	* When asked to do "count", this still show
	527	* the context which is nonsense, but the user
	528	* deserves to get that ;-).
	529	*/
	530	if (opt->pre_context) {
	531	unsigned from;
	532	if (opt->pre_context < lno)
	533	from = lno - opt->pre_context;
	534	else
	535	from = 1;
	536	if (from <= last_shown)
	537	from = last_shown + 1;
	538	if (last_shown && from != last_shown + 1)
9db56f71	539	fputs(hunk_mark, stdout);
83b5d2f5 JH	540	while (from < lno) {
	541	pcl = &prev[lno-from-1];
	542	show_line(opt, pcl->bol, pcl->eol,
	543	name, from, '-');
	544	from++;
	545	}
	546	last_shown = lno-1;
	547	}
	548	if (last_shown && lno != last_shown + 1)
9db56f71	549	fputs(hunk_mark, stdout);
83b5d2f5 JH	550	if (!opt->count)
	551	show_line(opt, bol, eol, name, lno, ':');
	552	last_shown = last_hit = lno;
	553	}
	554	else if (last_hit &&
	555	lno <= last_hit + opt->post_context) {
	556	/* If the last hit is within the post context,
	557	* we need to show this line.
	558	*/
	559	if (last_shown && lno != last_shown + 1)
9db56f71	560	fputs(hunk_mark, stdout);
83b5d2f5 JH	561	show_line(opt, bol, eol, name, lno, '-');
	562	last_shown = lno;
	563	}
	564	if (opt->pre_context) {
	565	memmove(prev+1, prev,
	566	(opt->pre_context-1) * sizeof(*prev));
	567	prev->bol = bol;
	568	prev->eol = eol;
	569	}
	570
	571	next_line:
	572	bol = eol + 1;
	573	if (!left)
	574	break;
	575	left--;
	576	lno++;
	577	}
	578
b48fb5b6	579	free(prev);
0ab7befa JH	580	if (collect_hits)
0ab7befa JH	581	return 0;
b48fb5b6	582
83b5d2f5 JH	583	if (opt->status_only)
	584	return 0;
	585	if (opt->unmatch_name_only) {
	586	/* We did not see any hit, so we want to show this */
83caecca	587	show_name(opt, name);
83b5d2f5 JH	588	return 1;
	589	}
	590
	591	/* NEEDSWORK:
	592	* The real "grep -c foo *.c" gives many "bar.c:0" lines,
	593	* which feels mostly useless but sometimes useful. Maybe
	594	* make it another option? For now suppress them.
	595	*/
	596	if (opt->count && count)
83caecca RZ	597	printf("%s%c%u\n", name,
83caecca RZ	598	opt->null_following_name ? '\0' : ':', count);
83b5d2f5 JH	599	return !!last_hit;
	600	}
	601
0ab7befa JH	602	static void clr_hit_marker(struct grep_expr *x)
	603	{
	604	/* All-hit markers are meaningful only at the very top level
	605	* OR node.
	606	*/
	607	while (1) {
	608	x->hit = 0;
	609	if (x->node != GREP_NODE_OR)
	610	return;
	611	x->u.binary.left->hit = 0;
	612	x = x->u.binary.right;
	613	}
	614	}
	615
	616	static int chk_hit_marker(struct grep_expr *x)
	617	{
	618	/* Top level nodes have hit markers. See if they all are hits */
	619	while (1) {
	620	if (x->node != GREP_NODE_OR)
	621	return x->hit;
	622	if (!x->u.binary.left->hit)
	623	return 0;
	624	x = x->u.binary.right;
	625	}
	626	}
	627
	628	int grep_buffer(struct grep_opt opt, const char name, char *buf, unsigned long size)
	629	{
	630	/*
	631	* we do not have to do the two-pass grep when we do not check
	632	* buffer-wide "all-match".
	633	*/
	634	if (!opt->all_match)
	635	return grep_buffer_1(opt, name, buf, size, 0);
	636
	637	/* Otherwise the toplevel "or" terms hit a bit differently.
	638	* We first clear hit markers from them.
	639	*/
	640	clr_hit_marker(opt->pattern_expression);
	641	grep_buffer_1(opt, name, buf, size, 1);
	642
	643	if (!chk_hit_marker(opt->pattern_expression))
	644	return 0;
	645
	646	return grep_buffer_1(opt, name, buf, size, 0);
	647	}