X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=grep.c;h=486230b511952dcf975199c82a5265d1906999cd;hb=a78f5582fca15950eb43f93b246e3778d0ae84da;hp=04c777a20c1a8c10417cc9d44e53e5b99dc32a27;hpb=77f143bf3e218857ec8e5244d7e862e8e0c1a041;p=git.git

diff --git a/grep.c b/grep.c
index 04c777a20..486230b51 100644
--- a/grep.c
+++ b/grep.c
@@ -1,25 +1,34 @@
 #include "cache.h"
 #include "grep.h"
+#include "userdiff.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->patternlen = strlen(pat);
 	p->origin = "header";
 	p->no = 0;
 	p->token = GREP_PATTERN_HEAD;
 	p->field = field;
-	*opt->pattern_tail = p;
-	opt->pattern_tail = &p->next;
+	*opt->header_tail = p;
+	opt->header_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)
+{
+	append_grep_pat(opt, pat, strlen(pat), origin, no, t);
+}
+
+void append_grep_pat(struct grep_opt *opt, const char *pat, size_t patlen,
+		     const char *origin, int no, enum grep_pat_token t)
 {
 	struct grep_pat *p = xcalloc(1, sizeof(*p));
 	p->pattern = pat;
+	p->patternlen = patlen;
 	p->origin = origin;
 	p->no = no;
 	p->token = t;
@@ -28,11 +37,122 @@ void append_grep_pattern(struct grep_opt *opt, const char *pat,
 	p->next = NULL;
 }
 
-static int is_fixed(const char *s)
+struct grep_opt *grep_opt_dup(const struct grep_opt *opt)
+{
+	struct grep_pat *pat;
+	struct grep_opt *ret = xmalloc(sizeof(struct grep_opt));
+	*ret = *opt;
+
+	ret->pattern_list = NULL;
+	ret->pattern_tail = &ret->pattern_list;
+
+	for(pat = opt->pattern_list; pat != NULL; pat = pat->next)
+	{
+		if(pat->token == GREP_PATTERN_HEAD)
+			append_header_grep_pattern(ret, pat->field,
+						   pat->pattern);
+		else
+			append_grep_pat(ret, pat->pattern, pat->patternlen,
+					pat->origin, pat->no, pat->token);
+	}
+
+	return ret;
+}
+
+static NORETURN void compile_regexp_failed(const struct grep_pat *p,
+		const char *error)
+{
+	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;
+
+	die("%s'%s': %s", where, p->pattern, error);
+}
+
+#ifdef USE_LIBPCRE
+static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
+{
+	const char *error;
+	int erroffset;
+	int options = 0;
+
+	if (opt->ignore_case)
+		options |= PCRE_CASELESS;
+
+	p->pcre_regexp = pcre_compile(p->pattern, options, &error, &erroffset,
+			NULL);
+	if (!p->pcre_regexp)
+		compile_regexp_failed(p, error);
+
+	p->pcre_extra_info = pcre_study(p->pcre_regexp, 0, &error);
+	if (!p->pcre_extra_info && error)
+		die("%s", error);
+}
+
+static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
+		regmatch_t *match, int eflags)
 {
-	while (*s && !is_regex_special(*s))
-		s++;
-	return !*s;
+	int ovector[30], ret, flags = 0;
+
+	if (eflags & REG_NOTBOL)
+		flags |= PCRE_NOTBOL;
+
+	ret = pcre_exec(p->pcre_regexp, p->pcre_extra_info, line, eol - line,
+			0, flags, ovector, ARRAY_SIZE(ovector));
+	if (ret < 0 && ret != PCRE_ERROR_NOMATCH)
+		die("pcre_exec failed with error code %d", ret);
+	if (ret > 0) {
+		ret = 0;
+		match->rm_so = ovector[0];
+		match->rm_eo = ovector[1];
+	}
+
+	return ret;
+}
+
+static void free_pcre_regexp(struct grep_pat *p)
+{
+	pcre_free(p->pcre_regexp);
+	pcre_free(p->pcre_extra_info);
+}
+#else /* !USE_LIBPCRE */
+static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
+{
+	die("cannot use Perl-compatible regexes when not compiled with USE_LIBPCRE");
+}
+
+static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
+		regmatch_t *match, int eflags)
+{
+	return 1;
+}
+
+static void free_pcre_regexp(struct grep_pat *p)
+{
+}
+#endif /* !USE_LIBPCRE */
+
+static int is_fixed(const char *s, size_t len)
+{
+	size_t i;
+
+	/* regcomp cannot accept patterns with NULs so we
+	 * consider any pattern containing a NUL fixed.
+	 */
+	if (memchr(s, 0, len))
+		return 1;
+
+	for (i = 0; i < len; i++) {
+		if (is_regex_special(s[i]))
+			return 0;
+	}
+
+	return 1;
 }
 
 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
@@ -40,28 +160,39 @@ static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 	int err;
 
 	p->word_regexp = opt->word_regexp;
+	p->ignore_case = opt->ignore_case;
 
-	if (opt->fixed || is_fixed(p->pattern))
+	if (opt->fixed || is_fixed(p->pattern, p->patternlen))
 		p->fixed = 1;
-	if (opt->regflags & REG_ICASE)
+	else
 		p->fixed = 0;
-	if (p->fixed)
+
+	if (p->fixed) {
+		if (opt->regflags & REG_ICASE || p->ignore_case) {
+			static char trans[256];
+			int i;
+			for (i = 0; i < 256; i++)
+				trans[i] = tolower(i);
+			p->kws = kwsalloc(trans);
+		} else {
+			p->kws = kwsalloc(NULL);
+		}
+		kwsincr(p->kws, p->pattern, p->patternlen);
+		kwsprep(p->kws);
 		return;
+	}
+
+	if (opt->pcre) {
+		compile_pcre_regexp(p, opt);
+		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);
+		compile_regexp_failed(p, errbuf);
 	}
 }
 
@@ -167,12 +298,73 @@ static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 	return compile_pattern_or(list);
 }
 
-void compile_grep_patterns(struct grep_opt *opt)
+static struct grep_expr *grep_true_expr(void)
+{
+	struct grep_expr *z = xcalloc(1, sizeof(*z));
+	z->node = GREP_NODE_TRUE;
+	return z;
+}
+
+static struct grep_expr *grep_or_expr(struct grep_expr *left, struct grep_expr *right)
+{
+	struct grep_expr *z = xcalloc(1, sizeof(*z));
+	z->node = GREP_NODE_OR;
+	z->u.binary.left = left;
+	z->u.binary.right = right;
+	return z;
+}
+
+static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
 {
 	struct grep_pat *p;
+	struct grep_expr *header_expr;
+	struct grep_expr *(header_group[GREP_HEADER_FIELD_MAX]);
+	enum grep_header_field fld;
 
-	if (opt->all_match)
-		opt->extended = 1;
+	if (!opt->header_list)
+		return NULL;
+	p = opt->header_list;
+	for (p = opt->header_list; p; p = p->next) {
+		if (p->token != GREP_PATTERN_HEAD)
+			die("bug: a non-header pattern in grep header list.");
+		if (p->field < 0 || GREP_HEADER_FIELD_MAX <= p->field)
+			die("bug: unknown header field %d", p->field);
+		compile_regexp(p, opt);
+	}
+
+	for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++)
+		header_group[fld] = NULL;
+
+	for (p = opt->header_list; p; p = p->next) {
+		struct grep_expr *h;
+		struct grep_pat *pp = p;
+
+		h = compile_pattern_atom(&pp);
+		if (!h || pp != p->next)
+			die("bug: malformed header expr");
+		if (!header_group[p->field]) {
+			header_group[p->field] = h;
+			continue;
+		}
+		header_group[p->field] = grep_or_expr(h, header_group[p->field]);
+	}
+
+	header_expr = NULL;
+
+	for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++) {
+		if (!header_group[fld])
+			continue;
+		if (!header_expr)
+			header_expr = grep_true_expr();
+		header_expr = grep_or_expr(header_group[fld], header_expr);
+	}
+	return header_expr;
+}
+
+void compile_grep_patterns(struct grep_opt *opt)
+{
+	struct grep_pat *p;
+	struct grep_expr *header_expr = prep_header_patterns(opt);
 
 	for (p = opt->pattern_list; p; p = p->next) {
 		switch (p->token) {
@@ -187,22 +379,32 @@ void compile_grep_patterns(struct grep_opt *opt)
 		}
 	}
 
-	if (!opt->extended)
+	if (opt->all_match || header_expr)
+		opt->extended = 1;
+	else if (!opt->extended)
 		return;
 
-	/* Then bundle them up in an expression.
-	 * A classic recursive descent parser would do.
-	 */
 	p = opt->pattern_list;
 	if (p)
 		opt->pattern_expression = compile_pattern_expr(&p);
 	if (p)
 		die("incomplete pattern expression: %s", p->pattern);
+
+	if (!header_expr)
+		return;
+
+	if (!opt->pattern_expression)
+		opt->pattern_expression = header_expr;
+	else
+		opt->pattern_expression = grep_or_expr(opt->pattern_expression,
+						       header_expr);
+	opt->all_match = 1;
 }
 
 static void free_pattern_expr(struct grep_expr *x)
 {
 	switch (x->node) {
+	case GREP_NODE_TRUE:
 	case GREP_NODE_ATOM:
 		break;
 	case GREP_NODE_NOT:
@@ -227,7 +429,12 @@ void free_grep_patterns(struct grep_opt *opt)
 		case GREP_PATTERN: /* atom */
 		case GREP_PATTERN_HEAD:
 		case GREP_PATTERN_BODY:
-			regfree(&p->regexp);
+			if (p->kws)
+				kwsfree(p->kws);
+			else if (p->pcre_regexp)
+				free_pcre_regexp(p);
+			else
+				regfree(&p->regexp);
 			break;
 		default:
 			break;
@@ -256,25 +463,72 @@ static int word_char(char ch)
 	return isalnum(ch) || ch == '_';
 }
 
+static void output_color(struct grep_opt *opt, const void *data, size_t size,
+			 const char *color)
+{
+	if (want_color(opt->color) && color && color[0]) {
+		opt->output(opt, color, strlen(color));
+		opt->output(opt, data, size);
+		opt->output(opt, GIT_COLOR_RESET, strlen(GIT_COLOR_RESET));
+	} else
+		opt->output(opt, data, size);
+}
+
+static void output_sep(struct grep_opt *opt, char sign)
+{
+	if (opt->null_following_name)
+		opt->output(opt, "\0", 1);
+	else
+		output_color(opt, &sign, 1, opt->color_sep);
+}
+
 static void show_name(struct grep_opt *opt, const char *name)
 {
-	printf("%s%c", name, opt->null_following_name ? '\0' : '\n');
+	output_color(opt, name, strlen(name), opt->color_filename);
+	opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 }
 
-static int fixmatch(const char *pattern, char *line, regmatch_t *match)
+static int fixmatch(struct grep_pat *p, char *line, char *eol,
+		    regmatch_t *match)
 {
-	char *hit = strstr(line, pattern);
-	if (!hit) {
+	struct kwsmatch kwsm;
+	size_t offset = kwsexec(p->kws, line, eol - line, &kwsm);
+	if (offset == -1) {
 		match->rm_so = match->rm_eo = -1;
 		return REG_NOMATCH;
-	}
-	else {
-		match->rm_so = hit - line;
-		match->rm_eo = match->rm_so + strlen(pattern);
+	} else {
+		match->rm_so = offset;
+		match->rm_eo = match->rm_so + kwsm.size[0];
 		return 0;
 	}
 }
 
+static int regmatch(const regex_t *preg, char *line, char *eol,
+		    regmatch_t *match, int eflags)
+{
+#ifdef REG_STARTEND
+	match->rm_so = 0;
+	match->rm_eo = eol - line;
+	eflags |= REG_STARTEND;
+#endif
+	return regexec(preg, line, 1, match, eflags);
+}
+
+static int patmatch(struct grep_pat *p, char *line, char *eol,
+		    regmatch_t *match, int eflags)
+{
+	int hit;
+
+	if (p->fixed)
+		hit = !fixmatch(p, line, eol, match);
+	else if (p->pcre_regexp)
+		hit = !pcrematch(p, line, eol, match, eflags);
+	else
+		hit = !regmatch(&p->regexp, line, eol, match, eflags);
+
+	return hit;
+}
+
 static int strip_timestamp(char *bol, char **eol_p)
 {
 	char *eol = *eol_p;
@@ -305,6 +559,7 @@ static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 {
 	int hit = 0;
 	int saved_ch = 0;
+	const char *start = bol;
 
 	if ((p->token != GREP_PATTERN) &&
 	    ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
@@ -323,14 +578,11 @@ static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 	}
 
  again:
-	if (p->fixed)
-		hit = !fixmatch(p->pattern, bol, pmatch);
-	else
-		hit = !regexec(&p->regexp, bol, 1, pmatch, eflags);
+	hit = patmatch(p, bol, eol, pmatch, eflags);
 
 	if (hit && p->word_regexp) {
 		if ((pmatch[0].rm_so < 0) ||
-		    (eol - bol) <= pmatch[0].rm_so ||
+		    (eol - bol) < pmatch[0].rm_so ||
 		    (pmatch[0].rm_eo < 0) ||
 		    (eol - bol) < pmatch[0].rm_eo)
 			die("regexp returned nonsense");
@@ -349,6 +601,10 @@ static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 		else
 			hit = 0;
 
+		/* Words consist of at least one character. */
+		if (pmatch->rm_so == pmatch->rm_eo)
+			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
@@ -359,12 +615,17 @@ static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 			bol = pmatch[0].rm_so + bol + 1;
 			while (word_char(bol[-1]) && bol < eol)
 				bol++;
+			eflags |= REG_NOTBOL;
 			if (bol < eol)
 				goto again;
 		}
 	}
 	if (p->token == GREP_PATTERN_HEAD && saved_ch)
 		*eol = saved_ch;
+	if (hit) {
+		pmatch[0].rm_so += bol - start;
+		pmatch[0].rm_eo += bol - start;
+	}
 	return hit;
 }
 
@@ -377,6 +638,9 @@ static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
 	if (!x)
 		die("Not a valid grep expression");
 	switch (x->node) {
+	case GREP_NODE_TRUE:
+		h = 1;
+		break;
 	case GREP_NODE_ATOM:
 		h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
 		break;
@@ -479,33 +743,244 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
 		      const char *name, unsigned lno, char sign)
 {
 	int rest = eol - bol;
+	char *line_color = NULL;
+
+	if (opt->file_break && opt->last_shown == 0) {
+		if (opt->show_hunk_mark)
+			opt->output(opt, "\n", 1);
+	} else if (opt->pre_context || opt->post_context || opt->funcbody) {
+		if (opt->last_shown == 0) {
+			if (opt->show_hunk_mark) {
+				output_color(opt, "--", 2, opt->color_sep);
+				opt->output(opt, "\n", 1);
+			}
+		} else if (lno > opt->last_shown + 1) {
+			output_color(opt, "--", 2, opt->color_sep);
+			opt->output(opt, "\n", 1);
+		}
+	}
+	if (opt->heading && opt->last_shown == 0) {
+		output_color(opt, name, strlen(name), opt->color_filename);
+		opt->output(opt, "\n", 1);
+	}
+	opt->last_shown = lno;
 
-	if (opt->null_following_name)
-		sign = '\0';
-	if (opt->pathname)
-		printf("%s%c", name, sign);
-	if (opt->linenum)
-		printf("%d%c", lno, sign);
+	if (!opt->heading && opt->pathname) {
+		output_color(opt, name, strlen(name), opt->color_filename);
+		output_sep(opt, sign);
+	}
+	if (opt->linenum) {
+		char buf[32];
+		snprintf(buf, sizeof(buf), "%d", lno);
+		output_color(opt, buf, strlen(buf), opt->color_lineno);
+		output_sep(opt, sign);
+	}
 	if (opt->color) {
 		regmatch_t match;
 		enum grep_context ctx = GREP_CONTEXT_BODY;
 		int ch = *eol;
 		int eflags = 0;
 
+		if (sign == ':')
+			line_color = opt->color_selected;
+		else if (sign == '-')
+			line_color = opt->color_context;
+		else if (sign == '=')
+			line_color = opt->color_function;
 		*eol = '\0';
 		while (next_match(opt, bol, eol, ctx, &match, eflags)) {
-			printf("%.*s%s%.*s%s",
-			       (int)match.rm_so, bol,
-			       opt->color_match,
-			       (int)(match.rm_eo - match.rm_so), bol + match.rm_so,
-			       GIT_COLOR_RESET);
+			if (match.rm_so == match.rm_eo)
+				break;
+
+			output_color(opt, bol, match.rm_so, line_color);
+			output_color(opt, bol + match.rm_so,
+				     match.rm_eo - match.rm_so,
+				     opt->color_match);
 			bol += match.rm_eo;
 			rest -= match.rm_eo;
 			eflags = REG_NOTBOL;
 		}
 		*eol = ch;
 	}
-	printf("%.*s\n", rest, bol);
+	output_color(opt, bol, rest, line_color);
+	opt->output(opt, "\n", 1);
+}
+
+#ifndef NO_PTHREADS
+/*
+ * This lock protects access to the gitattributes machinery, which is
+ * not thread-safe.
+ */
+pthread_mutex_t grep_attr_mutex;
+
+static inline void grep_attr_lock(struct grep_opt *opt)
+{
+	if (opt->use_threads)
+		pthread_mutex_lock(&grep_attr_mutex);
+}
+
+static inline void grep_attr_unlock(struct grep_opt *opt)
+{
+	if (opt->use_threads)
+		pthread_mutex_unlock(&grep_attr_mutex);
+}
+#else
+#define grep_attr_lock(opt)
+#define grep_attr_unlock(opt)
+#endif
+
+static int match_funcname(struct grep_opt *opt, const char *name, char *bol, char *eol)
+{
+	xdemitconf_t *xecfg = opt->priv;
+	if (xecfg && !xecfg->find_func) {
+		struct userdiff_driver *drv;
+		grep_attr_lock(opt);
+		drv = userdiff_find_by_path(name);
+		grep_attr_unlock(opt);
+		if (drv && drv->funcname.pattern) {
+			const struct userdiff_funcname *pe = &drv->funcname;
+			xdiff_set_find_func(xecfg, pe->pattern, pe->cflags);
+		} else {
+			xecfg = opt->priv = NULL;
+		}
+	}
+
+	if (xecfg) {
+		char buf[1];
+		return xecfg->find_func(bol, eol - bol, buf, 1,
+					xecfg->find_func_priv) >= 0;
+	}
+
+	if (bol == eol)
+		return 0;
+	if (isalpha(*bol) || *bol == '_' || *bol == '$')
+		return 1;
+	return 0;
+}
+
+static void show_funcname_line(struct grep_opt *opt, const char *name,
+			       char *buf, char *bol, unsigned lno)
+{
+	while (bol > buf) {
+		char *eol = --bol;
+
+		while (bol > buf && bol[-1] != '\n')
+			bol--;
+		lno--;
+
+		if (lno <= opt->last_shown)
+			break;
+
+		if (match_funcname(opt, name, bol, eol)) {
+			show_line(opt, bol, eol, name, lno, '=');
+			break;
+		}
+	}
+}
+
+static void show_pre_context(struct grep_opt *opt, const char *name, char *buf,
+			     char *bol, char *end, unsigned lno)
+{
+	unsigned cur = lno, from = 1, funcname_lno = 0;
+	int funcname_needed = !!opt->funcname;
+
+	if (opt->funcbody && !match_funcname(opt, name, bol, end))
+		funcname_needed = 2;
+
+	if (opt->pre_context < lno)
+		from = lno - opt->pre_context;
+	if (from <= opt->last_shown)
+		from = opt->last_shown + 1;
+
+	/* Rewind. */
+	while (bol > buf &&
+	       cur > (funcname_needed == 2 ? opt->last_shown + 1 : from)) {
+		char *eol = --bol;
+
+		while (bol > buf && bol[-1] != '\n')
+			bol--;
+		cur--;
+		if (funcname_needed && match_funcname(opt, name, bol, eol)) {
+			funcname_lno = cur;
+			funcname_needed = 0;
+		}
+	}
+
+	/* We need to look even further back to find a function signature. */
+	if (opt->funcname && funcname_needed)
+		show_funcname_line(opt, name, buf, bol, cur);
+
+	/* Back forward. */
+	while (cur < lno) {
+		char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
+
+		while (*eol != '\n')
+			eol++;
+		show_line(opt, bol, eol, name, cur, sign);
+		bol = eol + 1;
+		cur++;
+	}
+}
+
+static int should_lookahead(struct grep_opt *opt)
+{
+	struct grep_pat *p;
+
+	if (opt->extended)
+		return 0; /* punt for too complex stuff */
+	if (opt->invert)
+		return 0;
+	for (p = opt->pattern_list; p; p = p->next) {
+		if (p->token != GREP_PATTERN)
+			return 0; /* punt for "header only" and stuff */
+	}
+	return 1;
+}
+
+static int look_ahead(struct grep_opt *opt,
+		      unsigned long *left_p,
+		      unsigned *lno_p,
+		      char **bol_p)
+{
+	unsigned lno = *lno_p;
+	char *bol = *bol_p;
+	struct grep_pat *p;
+	char *sp, *last_bol;
+	regoff_t earliest = -1;
+
+	for (p = opt->pattern_list; p; p = p->next) {
+		int hit;
+		regmatch_t m;
+
+		hit = patmatch(p, bol, bol + *left_p, &m, 0);
+		if (!hit || m.rm_so < 0 || m.rm_eo < 0)
+			continue;
+		if (earliest < 0 || m.rm_so < earliest)
+			earliest = m.rm_so;
+	}
+
+	if (earliest < 0) {
+		*bol_p = bol + *left_p;
+		*left_p = 0;
+		return 1;
+	}
+	for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
+		; /* find the beginning of the line */
+	last_bol = sp;
+
+	for (sp = bol; sp < last_bol; sp++) {
+		if (*sp == '\n')
+			lno++;
+	}
+	*left_p -= last_bol - bol;
+	*bol_p = last_bol;
+	*lno_p = lno;
+	return 0;
+}
+
+static void std_output(struct grep_opt *opt, const void *buf, size_t size)
+{
+	fwrite(buf, size, 1, stdout);
 }
 
 static int grep_buffer_1(struct grep_opt *opt, const char *name,
@@ -514,39 +989,71 @@ static int grep_buffer_1(struct grep_opt *opt, const char *name,
 	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;
+	int try_lookahead = 0;
+	int show_function = 0;
 	enum grep_context ctx = GREP_CONTEXT_HEAD;
+	xdemitconf_t xecfg;
+
+	if (!opt->output)
+		opt->output = std_output;
+
+	if (opt->pre_context || opt->post_context || opt->file_break ||
+	    opt->funcbody) {
+		/* Show hunk marks, except for the first file. */
+		if (opt->last_shown)
+			opt->show_hunk_mark = 1;
+		/*
+		 * If we're using threads then we can't easily identify
+		 * the first file.  Always put hunk marks in that case
+		 * and skip the very first one later in work_done().
+		 */
+		if (opt->output != std_output)
+			opt->show_hunk_mark = 1;
+	}
+	opt->last_shown = 0;
 
-	if (buffer_is_binary(buf, size)) {
-		switch (opt->binary) {
-		case GREP_BINARY_DEFAULT:
+	switch (opt->binary) {
+	case GREP_BINARY_DEFAULT:
+		if (buffer_is_binary(buf, size))
 			binary_match_only = 1;
-			break;
-		case GREP_BINARY_NOMATCH:
+		break;
+	case GREP_BINARY_NOMATCH:
+		if (buffer_is_binary(buf, size))
 			return 0; /* Assume unmatch */
-			break;
-		default:
-			break;
-		}
+		break;
+	case GREP_BINARY_TEXT:
+		break;
+	default:
+		die("bug: unknown binary handling mode");
 	}
 
-	if (opt->pre_context)
-		prev = xcalloc(opt->pre_context, sizeof(*prev));
-	if (opt->pre_context || opt->post_context)
-		hunk_mark = "--\n";
+	memset(&xecfg, 0, sizeof(xecfg));
+	opt->priv = &xecfg;
+
+	try_lookahead = should_lookahead(opt);
 
 	while (left) {
 		char *eol, ch;
 		int hit;
 
+		/*
+		 * look_ahead() skips quickly to the line that possibly
+		 * has the next hit; don't call it if we need to do
+		 * something more than just skipping the current line
+		 * in response to an unmatch for the current line.  E.g.
+		 * inside a post-context window, we will show the current
+		 * line as a context around the previous hit when it
+		 * doesn't hit.
+		 */
+		if (try_lookahead
+		    && !(last_hit
+			 && (show_function ||
+			     lno <= last_hit + opt->post_context))
+		    && look_ahead(opt, &left, &lno, &bol))
+			break;
 		eol = end_of_line(bol, &left);
 		ch = *eol;
 		*eol = 0;
@@ -575,59 +1082,40 @@ static int grep_buffer_1(struct grep_opt *opt, const char *name,
 			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;
 			}
+			if (opt->count)
+				goto next_line;
+			if (binary_match_only) {
+				opt->output(opt, "Binary file ", 12);
+				output_color(opt, name, strlen(name),
+					     opt->color_filename);
+				opt->output(opt, " matches\n", 9);
+				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;
+			if (opt->pre_context || opt->funcbody)
+				show_pre_context(opt, name, buf, bol, eol, lno);
+			else if (opt->funcname)
+				show_funcname_line(opt, name, buf, bol, lno);
+			show_line(opt, bol, eol, name, lno, ':');
+			last_hit = lno;
+			if (opt->funcbody)
+				show_function = 1;
+			goto next_line;
 		}
-		else if (last_hit &&
-			 lno <= last_hit + opt->post_context) {
+		if (show_function && match_funcname(opt, name, bol, eol))
+			show_function = 0;
+		if (show_function ||
+		    (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:
@@ -638,7 +1126,6 @@ static int grep_buffer_1(struct grep_opt *opt, const char *name,
 		lno++;
 	}
 
-	free(prev);
 	if (collect_hits)
 		return 0;
 
@@ -650,14 +1137,22 @@ static int grep_buffer_1(struct grep_opt *opt, const char *name,
 		return 1;
 	}
 
+	xdiff_clear_find_func(&xecfg);
+	opt->priv = NULL;
+
 	/* 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);
+	if (opt->count && count) {
+		char buf[32];
+		output_color(opt, name, strlen(name), opt->color_filename);
+		output_sep(opt, ':');
+		snprintf(buf, sizeof(buf), "%u\n", count);
+		opt->output(opt, buf, strlen(buf));
+		return 1;
+	}
 	return !!last_hit;
 }