1 files changed, 425 insertions, 126 deletions

diff --git a/grep.c b/grep.c
index 528b652f71..3d7cd0e96f 100644
--- a/grep.c
+++ b/grep.c
@@ -1,15 +1,23 @@
 #include "cache.h"
+#include "config.h"
 #include "grep.h"
 #include "userdiff.h"
 #include "xdiff-interface.h"
 #include "diff.h"
 #include "diffcore.h"
+#include "commit.h"
+#include "quote.h"
 
 static int grep_source_load(struct grep_source *gs);
 static int grep_source_is_binary(struct grep_source *gs);
 
 static struct grep_opt grep_defaults;
 
+static void std_output(struct grep_opt *opt, const void *buf, size_t size)
+{
+	fwrite(buf, size, 1, stdout);
+}
+
 /*
  * Initialize the grep_defaults template with hardcoded defaults.
  * We could let the compiler do this, but without C99 initializers
@@ -27,10 +35,8 @@ void init_grep_defaults(void)
 	memset(opt, 0, sizeof(*opt));
 	opt->relative = 1;
 	opt->pathname = 1;
-	opt->regflags = REG_NEWLINE;
 	opt->max_depth = -1;
 	opt->pattern_type_option = GREP_PATTERN_TYPE_UNSPECIFIED;
-	opt->extended_regexp_option = 0;
 	color_set(opt->color_context, "");
 	color_set(opt->color_filename, "");
 	color_set(opt->color_function, "");
@@ -40,6 +46,7 @@ void init_grep_defaults(void)
 	color_set(opt->color_selected, "");
 	color_set(opt->color_sep, GIT_COLOR_CYAN);
 	opt->color = -1;
+	opt->output = std_output;
 }
 
 static int parse_pattern_type_arg(const char *opt, const char *arg)
@@ -70,10 +77,7 @@ int grep_config(const char *var, const char *value, void *cb)
 		return -1;
 
 	if (!strcmp(var, "grep.extendedregexp")) {
-		if (git_config_bool(var, value))
-			opt->extended_regexp_option = 1;
-		else
-			opt->extended_regexp_option = 0;
+		opt->extended_regexp_option = git_config_bool(var, value);
 		return 0;
 	}
 
@@ -148,8 +152,8 @@ void grep_init(struct grep_opt *opt, const char *prefix)
 	opt->linenum = def->linenum;
 	opt->max_depth = def->max_depth;
 	opt->pathname = def->pathname;
-	opt->regflags = def->regflags;
 	opt->relative = def->relative;
+	opt->output = def->output;
 
 	color_set(opt->color_context, def->color_context);
 	color_set(opt->color_filename, def->color_filename);
@@ -161,48 +165,72 @@ void grep_init(struct grep_opt *opt, const char *prefix)
 	color_set(opt->color_sep, def->color_sep);
 }
 
-void grep_commit_pattern_type(enum grep_pattern_type pattern_type, struct grep_opt *opt)
+static void grep_set_pattern_type_option(enum grep_pattern_type pattern_type, struct grep_opt *opt)
 {
-	if (pattern_type != GREP_PATTERN_TYPE_UNSPECIFIED)
-		grep_set_pattern_type_option(pattern_type, opt);
-	else if (opt->pattern_type_option != GREP_PATTERN_TYPE_UNSPECIFIED)
-		grep_set_pattern_type_option(opt->pattern_type_option, opt);
-	else if (opt->extended_regexp_option)
-		grep_set_pattern_type_option(GREP_PATTERN_TYPE_ERE, opt);
-}
+	/*
+	 * When committing to the pattern type by setting the relevant
+	 * fields in grep_opt it's generally not necessary to zero out
+	 * the fields we're not choosing, since they won't have been
+	 * set by anything. The extended_regexp_option field is the
+	 * only exception to this.
+	 *
+	 * This is because in the process of parsing grep.patternType
+	 * & grep.extendedRegexp we set opt->pattern_type_option and
+	 * opt->extended_regexp_option, respectively. We then
+	 * internally use opt->extended_regexp_option to see if we're
+	 * compiling an ERE. It must be unset if that's not actually
+	 * the case.
+	 */
+	if (pattern_type != GREP_PATTERN_TYPE_ERE &&
+	    opt->extended_regexp_option)
+		opt->extended_regexp_option = 0;
 
-void grep_set_pattern_type_option(enum grep_pattern_type pattern_type, struct grep_opt *opt)
-{
 	switch (pattern_type) {
 	case GREP_PATTERN_TYPE_UNSPECIFIED:
 		/* fall through */
 
 	case GREP_PATTERN_TYPE_BRE:
-		opt->fixed = 0;
-		opt->pcre = 0;
-		opt->regflags &= ~REG_EXTENDED;
 		break;
 
 	case GREP_PATTERN_TYPE_ERE:
-		opt->fixed = 0;
-		opt->pcre = 0;
-		opt->regflags |= REG_EXTENDED;
+		opt->extended_regexp_option = 1;
 		break;
 
 	case GREP_PATTERN_TYPE_FIXED:
 		opt->fixed = 1;
-		opt->pcre = 0;
-		opt->regflags &= ~REG_EXTENDED;
 		break;
 
 	case GREP_PATTERN_TYPE_PCRE:
-		opt->fixed = 0;
-		opt->pcre = 1;
-		opt->regflags &= ~REG_EXTENDED;
+#ifdef USE_LIBPCRE2
+		opt->pcre2 = 1;
+#else
+		/*
+		 * It's important that pcre1 always be assigned to
+		 * even when there's no USE_LIBPCRE* defined. We still
+		 * call the PCRE stub function, it just dies with
+		 * "cannot use Perl-compatible regexes[...]".
+		 */
+		opt->pcre1 = 1;
+#endif
 		break;
 	}
 }
 
+void grep_commit_pattern_type(enum grep_pattern_type pattern_type, struct grep_opt *opt)
+{
+	if (pattern_type != GREP_PATTERN_TYPE_UNSPECIFIED)
+		grep_set_pattern_type_option(pattern_type, opt);
+	else if (opt->pattern_type_option != GREP_PATTERN_TYPE_UNSPECIFIED)
+		grep_set_pattern_type_option(opt->pattern_type_option, opt);
+	else if (opt->extended_regexp_option)
+		/*
+		 * This branch *must* happen after setting from the
+		 * opt->pattern_type_option above, we don't want
+		 * grep.extendedRegexp to override grep.patternType!
+		 */
+		grep_set_pattern_type_option(GREP_PATTERN_TYPE_ERE, opt);
+}
+
 static struct grep_pat *create_grep_pat(const char *pat, size_t patlen,
 					const char *origin, int no,
 					enum grep_pat_token t,
@@ -315,27 +343,69 @@ static NORETURN void compile_regexp_failed(const struct grep_pat *p,
 	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)
+static int is_fixed(const char *s, size_t len)
+{
+	size_t i;
+
+	for (i = 0; i < len; i++) {
+		if (is_regex_special(s[i]))
+			return 0;
+	}
+
+	return 1;
+}
+
+static int has_null(const char *s, size_t len)
+{
+	/*
+	 * regcomp cannot accept patterns with NULs so when using it
+	 * we consider any pattern containing a NUL fixed.
+	 */
+	if (memchr(s, 0, len))
+		return 1;
+
+	return 0;
+}
+
+#ifdef USE_LIBPCRE1
+static void compile_pcre1_regexp(struct grep_pat *p, const struct grep_opt *opt)
 {
 	const char *error;
 	int erroffset;
 	int options = PCRE_MULTILINE;
 
-	if (opt->ignore_case)
+	if (opt->ignore_case) {
+		if (has_non_ascii(p->pattern))
+			p->pcre1_tables = pcre_maketables();
 		options |= PCRE_CASELESS;
+	}
+	if (is_utf8_locale() && has_non_ascii(p->pattern))
+		options |= PCRE_UTF8;
 
-	p->pcre_regexp = pcre_compile(p->pattern, options, &error, &erroffset,
-			NULL);
-	if (!p->pcre_regexp)
+	p->pcre1_regexp = pcre_compile(p->pattern, options, &error, &erroffset,
+				      p->pcre1_tables);
+	if (!p->pcre1_regexp)
 		compile_regexp_failed(p, error);
 
-	p->pcre_extra_info = pcre_study(p->pcre_regexp, 0, &error);
-	if (!p->pcre_extra_info && error)
+	p->pcre1_extra_info = pcre_study(p->pcre1_regexp, GIT_PCRE_STUDY_JIT_COMPILE, &error);
+	if (!p->pcre1_extra_info && error)
 		die("%s", error);
+
+#ifdef GIT_PCRE1_USE_JIT
+	pcre_config(PCRE_CONFIG_JIT, &p->pcre1_jit_on);
+	if (p->pcre1_jit_on == 1) {
+		p->pcre1_jit_stack = pcre_jit_stack_alloc(1, 1024 * 1024);
+		if (!p->pcre1_jit_stack)
+			die("Couldn't allocate PCRE JIT stack");
+		pcre_assign_jit_stack(p->pcre1_extra_info, NULL, p->pcre1_jit_stack);
+	} else if (p->pcre1_jit_on != 0) {
+		die("BUG: The pcre1_jit_on variable should be 0 or 1, not %d",
+		    p->pcre1_jit_on);
+	}
+#endif
 }
 
-static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
+static int pcre1match(struct grep_pat *p, const char *line, const char *eol,
 		regmatch_t *match, int eflags)
 {
 	int ovector[30], ret, flags = 0;
@@ -343,8 +413,19 @@ static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
 	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));
+#ifdef GIT_PCRE1_USE_JIT
+	if (p->pcre1_jit_on) {
+		ret = pcre_jit_exec(p->pcre1_regexp, p->pcre1_extra_info, line,
+				    eol - line, 0, flags, ovector,
+				    ARRAY_SIZE(ovector), p->pcre1_jit_stack);
+	} else
+#endif
+	{
+		ret = pcre_exec(p->pcre1_regexp, p->pcre1_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) {
@@ -356,74 +437,262 @@ static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
 	return ret;
 }
 
-static void free_pcre_regexp(struct grep_pat *p)
+static void free_pcre1_regexp(struct grep_pat *p)
 {
-	pcre_free(p->pcre_regexp);
-	pcre_free(p->pcre_extra_info);
+	pcre_free(p->pcre1_regexp);
+#ifdef GIT_PCRE1_USE_JIT
+	if (p->pcre1_jit_on) {
+		pcre_free_study(p->pcre1_extra_info);
+		pcre_jit_stack_free(p->pcre1_jit_stack);
+	} else
+#endif
+	{
+		pcre_free(p->pcre1_extra_info);
+	}
+	pcre_free((void *)p->pcre1_tables);
 }
-#else /* !USE_LIBPCRE */
-static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
+#else /* !USE_LIBPCRE1 */
+static void compile_pcre1_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,
+static int pcre1match(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)
+static void free_pcre1_regexp(struct grep_pat *p)
 {
 }
-#endif /* !USE_LIBPCRE */
+#endif /* !USE_LIBPCRE1 */
 
-static int is_fixed(const char *s, size_t len)
+#ifdef USE_LIBPCRE2
+static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt)
 {
-	size_t i;
+	int error;
+	PCRE2_UCHAR errbuf[256];
+	PCRE2_SIZE erroffset;
+	int options = PCRE2_MULTILINE;
+	const uint8_t *character_tables = NULL;
+	int jitret;
+	int patinforet;
+	size_t jitsizearg;
 
-	/* regcomp cannot accept patterns with NULs so we
-	 * consider any pattern containing a NUL fixed.
-	 */
-	if (memchr(s, 0, len))
-		return 1;
+	assert(opt->pcre2);
 
-	for (i = 0; i < len; i++) {
-		if (is_regex_special(s[i]))
-			return 0;
+	p->pcre2_compile_context = NULL;
+
+	if (opt->ignore_case) {
+		if (has_non_ascii(p->pattern)) {
+			character_tables = pcre2_maketables(NULL);
+			p->pcre2_compile_context = pcre2_compile_context_create(NULL);
+			pcre2_set_character_tables(p->pcre2_compile_context, character_tables);
+		}
+		options |= PCRE2_CASELESS;
+	}
+	if (is_utf8_locale() && has_non_ascii(p->pattern))
+		options |= PCRE2_UTF;
+
+	p->pcre2_pattern = pcre2_compile((PCRE2_SPTR)p->pattern,
+					 p->patternlen, options, &error, &erroffset,
+					 p->pcre2_compile_context);
+
+	if (p->pcre2_pattern) {
+		p->pcre2_match_data = pcre2_match_data_create_from_pattern(p->pcre2_pattern, NULL);
+		if (!p->pcre2_match_data)
+			die("Couldn't allocate PCRE2 match data");
+	} else {
+		pcre2_get_error_message(error, errbuf, sizeof(errbuf));
+		compile_regexp_failed(p, (const char *)&errbuf);
+	}
+
+	pcre2_config(PCRE2_CONFIG_JIT, &p->pcre2_jit_on);
+	if (p->pcre2_jit_on == 1) {
+		jitret = pcre2_jit_compile(p->pcre2_pattern, PCRE2_JIT_COMPLETE);
+		if (jitret)
+			die("Couldn't JIT the PCRE2 pattern '%s', got '%d'\n", p->pattern, jitret);
+
+		/*
+		 * The pcre2_config(PCRE2_CONFIG_JIT, ...) call just
+		 * tells us whether the library itself supports JIT,
+		 * but to see whether we're going to be actually using
+		 * JIT we need to extract PCRE2_INFO_JITSIZE from the
+		 * pattern *after* we do pcre2_jit_compile() above.
+		 *
+		 * This is because if the pattern contains the
+		 * (*NO_JIT) verb (see pcre2syntax(3))
+		 * pcre2_jit_compile() will exit early with 0. If we
+		 * then proceed to call pcre2_jit_match() further down
+		 * the line instead of pcre2_match() we'll either
+		 * segfault (pre PCRE 10.31) or run into a fatal error
+		 * (post PCRE2 10.31)
+		 */
+		patinforet = pcre2_pattern_info(p->pcre2_pattern, PCRE2_INFO_JITSIZE, &jitsizearg);
+		if (patinforet)
+			BUG("pcre2_pattern_info() failed: %d", patinforet);
+		if (jitsizearg == 0) {
+			p->pcre2_jit_on = 0;
+			return;
+		}
+
+		p->pcre2_jit_stack = pcre2_jit_stack_create(1, 1024 * 1024, NULL);
+		if (!p->pcre2_jit_stack)
+			die("Couldn't allocate PCRE2 JIT stack");
+		p->pcre2_match_context = pcre2_match_context_create(NULL);
+		if (!p->pcre2_match_context)
+			die("Couldn't allocate PCRE2 match context");
+		pcre2_jit_stack_assign(p->pcre2_match_context, NULL, p->pcre2_jit_stack);
+	} else if (p->pcre2_jit_on != 0) {
+		die("BUG: The pcre2_jit_on variable should be 0 or 1, not %d",
+		    p->pcre1_jit_on);
+	}
+}
+
+static int pcre2match(struct grep_pat *p, const char *line, const char *eol,
+		regmatch_t *match, int eflags)
+{
+	int ret, flags = 0;
+	PCRE2_SIZE *ovector;
+	PCRE2_UCHAR errbuf[256];
+
+	if (eflags & REG_NOTBOL)
+		flags |= PCRE2_NOTBOL;
+
+	if (p->pcre2_jit_on)
+		ret = pcre2_jit_match(p->pcre2_pattern, (unsigned char *)line,
+				      eol - line, 0, flags, p->pcre2_match_data,
+				      NULL);
+	else
+		ret = pcre2_match(p->pcre2_pattern, (unsigned char *)line,
+				  eol - line, 0, flags, p->pcre2_match_data,
+				  NULL);
+
+	if (ret < 0 && ret != PCRE2_ERROR_NOMATCH) {
+		pcre2_get_error_message(ret, errbuf, sizeof(errbuf));
+		die("%s failed with error code %d: %s",
+		    (p->pcre2_jit_on ? "pcre2_jit_match" : "pcre2_match"), ret,
+		    errbuf);
+	}
+	if (ret > 0) {
+		ovector = pcre2_get_ovector_pointer(p->pcre2_match_data);
+		ret = 0;
+		match->rm_so = (int)ovector[0];
+		match->rm_eo = (int)ovector[1];
 	}
 
+	return ret;
+}
+
+static void free_pcre2_pattern(struct grep_pat *p)
+{
+	pcre2_compile_context_free(p->pcre2_compile_context);
+	pcre2_code_free(p->pcre2_pattern);
+	pcre2_match_data_free(p->pcre2_match_data);
+	pcre2_jit_stack_free(p->pcre2_jit_stack);
+	pcre2_match_context_free(p->pcre2_match_context);
+}
+#else /* !USE_LIBPCRE2 */
+static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt)
+{
+	/*
+	 * Unreachable until USE_LIBPCRE2 becomes synonymous with
+	 * USE_LIBPCRE. See the sibling comment in
+	 * grep_set_pattern_type_option().
+	 */
+	die("cannot use Perl-compatible regexes when not compiled with USE_LIBPCRE");
+}
+
+static int pcre2match(struct grep_pat *p, const char *line, const char *eol,
+		regmatch_t *match, int eflags)
+{
 	return 1;
 }
 
+static void free_pcre2_pattern(struct grep_pat *p)
+{
+}
+#endif /* !USE_LIBPCRE2 */
+
+static void compile_fixed_regexp(struct grep_pat *p, struct grep_opt *opt)
+{
+	struct strbuf sb = STRBUF_INIT;
+	int err;
+	int regflags = 0;
+
+	basic_regex_quote_buf(&sb, p->pattern);
+	if (opt->ignore_case)
+		regflags |= REG_ICASE;
+	err = regcomp(&p->regexp, sb.buf, regflags);
+	if (opt->debug)
+		fprintf(stderr, "fixed %s\n", sb.buf);
+	strbuf_release(&sb);
+	if (err) {
+		char errbuf[1024];
+		regerror(err, &p->regexp, errbuf, sizeof(errbuf));
+		regfree(&p->regexp);
+		compile_regexp_failed(p, errbuf);
+	}
+}
+
 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 {
+	int ascii_only;
 	int err;
+	int regflags = REG_NEWLINE;
 
 	p->word_regexp = opt->word_regexp;
 	p->ignore_case = opt->ignore_case;
+	ascii_only     = !has_non_ascii(p->pattern);
 
-	if (opt->fixed || is_fixed(p->pattern, p->patternlen))
-		p->fixed = 1;
-	else
-		p->fixed = 0;
+	/*
+	 * Even when -F (fixed) asks us to do a non-regexp search, we
+	 * may not be able to correctly case-fold when -i
+	 * (ignore-case) is asked (in which case, we'll synthesize a
+	 * regexp to match the pattern that matches regexp special
+	 * characters literally, while ignoring case differences).  On
+	 * the other hand, even without -F, if the pattern does not
+	 * have any regexp special characters and there is no need for
+	 * case-folding search, we can internally turn it into a
+	 * simple string match using kws.  p->fixed tells us if we
+	 * want to use kws.
+	 */
+	if (opt->fixed ||
+	    has_null(p->pattern, p->patternlen) ||
+	    is_fixed(p->pattern, p->patternlen))
+		p->fixed = !p->ignore_case || ascii_only;
 
 	if (p->fixed) {
-		if (opt->regflags & REG_ICASE || p->ignore_case)
-			p->kws = kwsalloc(tolower_trans_tbl);
-		else
-			p->kws = kwsalloc(NULL);
+		p->kws = kwsalloc(p->ignore_case ? tolower_trans_tbl : NULL);
 		kwsincr(p->kws, p->pattern, p->patternlen);
 		kwsprep(p->kws);
 		return;
+	} else if (opt->fixed) {
+		/*
+		 * We come here when the pattern has the non-ascii
+		 * characters we cannot case-fold, and asked to
+		 * ignore-case.
+		 */
+		compile_fixed_regexp(p, opt);
+		return;
 	}
 
-	if (opt->pcre) {
-		compile_pcre_regexp(p, opt);
+	if (opt->pcre2) {
+		compile_pcre2_pattern(p, opt);
 		return;
 	}
 
-	err = regcomp(&p->regexp, p->pattern, opt->regflags);
+	if (opt->pcre1) {
+		compile_pcre1_regexp(p, opt);
+		return;
+	}
+
+	if (p->ignore_case)
+		regflags |= REG_ICASE;
+	if (opt->extended_regexp_option)
+		regflags |= REG_EXTENDED;
+	err = regcomp(&p->regexp, p->pattern, regflags);
 	if (err) {
 		char errbuf[1024];
 		regerror(err, &p->regexp, errbuf, 1024);
@@ -643,10 +912,10 @@ static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
 
 	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.");
+			die("BUG: a non-header pattern in grep header list.");
 		if (p->field < GREP_HEADER_FIELD_MIN ||
 		    GREP_HEADER_FIELD_MAX <= p->field)
-			die("bug: unknown header field %d", p->field);
+			die("BUG: unknown header field %d", p->field);
 		compile_regexp(p, opt);
 	}
 
@@ -659,7 +928,7 @@ static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
 
 		h = compile_pattern_atom(&pp);
 		if (!h || pp != p->next)
-			die("bug: malformed header expr");
+			die("BUG: malformed header expr");
 		if (!header_group[p->field]) {
 			header_group[p->field] = h;
 			continue;
@@ -775,8 +1044,10 @@ void free_grep_patterns(struct grep_opt *opt)
 		case GREP_PATTERN_BODY:
 			if (p->kws)
 				kwsfree(p->kws);
-			else if (p->pcre_regexp)
-				free_pcre_regexp(p);
+			else if (p->pcre1_regexp)
+				free_pcre1_regexp(p);
+			else if (p->pcre2_pattern)
+				free_pcre2_pattern(p);
 			else
 				regfree(&p->regexp);
 			free(p->pattern);
@@ -848,17 +1119,6 @@ static int fixmatch(struct grep_pat *p, char *line, char *eol,
 	}
 }
 
-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)
 {
@@ -866,10 +1126,13 @@ static int patmatch(struct grep_pat *p, char *line, char *eol,
 
 	if (p->fixed)
 		hit = !fixmatch(p, line, eol, match);
-	else if (p->pcre_regexp)
-		hit = !pcrematch(p, line, eol, match, eflags);
+	else if (p->pcre1_regexp)
+		hit = !pcre1match(p, line, eol, match, eflags);
+	else if (p->pcre2_pattern)
+		hit = !pcre2match(p, line, eol, match, eflags);
 	else
-		hit = !regmatch(&p->regexp, line, eol, match, eflags);
+		hit = !regexec_buf(&p->regexp, line, eol - line, 1, match,
+				   eflags);
 
 	return hit;
 }
@@ -1124,7 +1387,7 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
 	}
 	if (opt->linenum) {
 		char buf[32];
-		snprintf(buf, sizeof(buf), "%d", lno);
+		xsnprintf(buf, sizeof(buf), "%d", lno);
 		output_color(opt, buf, strlen(buf), opt->color_lineno);
 		output_sep(opt, sign);
 	}
@@ -1239,31 +1502,52 @@ static void show_funcname_line(struct grep_opt *opt, struct grep_source *gs,
 	}
 }
 
+static int is_empty_line(const char *bol, const char *eol);
+
 static void show_pre_context(struct grep_opt *opt, struct grep_source *gs,
 			     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, gs, bol, end))
-		funcname_needed = 2;
+	unsigned cur = lno, from = 1, funcname_lno = 0, orig_from;
+	int funcname_needed = !!opt->funcname, comment_needed = 0;
 
 	if (opt->pre_context < lno)
 		from = lno - opt->pre_context;
 	if (from <= opt->last_shown)
 		from = opt->last_shown + 1;
+	orig_from = from;
+	if (opt->funcbody) {
+		if (match_funcname(opt, gs, bol, end))
+			comment_needed = 1;
+		else
+			funcname_needed = 1;
+		from = opt->last_shown + 1;
+	}
 
 	/* Rewind. */
-	while (bol > gs->buf &&
-	       cur > (funcname_needed == 2 ? opt->last_shown + 1 : from)) {
+	while (bol > gs->buf && cur > from) {
+		char *next_bol = bol;
 		char *eol = --bol;
 
 		while (bol > gs->buf && bol[-1] != '\n')
 			bol--;
 		cur--;
+		if (comment_needed && (is_empty_line(bol, eol) ||
+				       match_funcname(opt, gs, bol, eol))) {
+			comment_needed = 0;
+			from = orig_from;
+			if (cur < from) {
+				cur++;
+				bol = next_bol;
+				break;
+			}
+		}
 		if (funcname_needed && match_funcname(opt, gs, bol, eol)) {
 			funcname_lno = cur;
 			funcname_needed = 0;
+			if (opt->funcbody)
+				comment_needed = 1;
+			else
+				from = orig_from;
 		}
 	}
 
@@ -1339,11 +1623,6 @@ static int look_ahead(struct grep_opt *opt,
 	return 0;
 }
 
-static void std_output(struct grep_opt *opt, const void *buf, size_t size)
-{
-	fwrite(buf, size, 1, stdout);
-}
-
 static int fill_textconv_grep(struct userdiff_driver *driver,
 			      struct grep_source *gs)
 {
@@ -1361,11 +1640,11 @@ static int fill_textconv_grep(struct userdiff_driver *driver,
 	 */
 	df = alloc_filespec(gs->path);
 	switch (gs->type) {
-	case GREP_SOURCE_SHA1:
+	case GREP_SOURCE_OID:
 		fill_filespec(df, gs->identifier, 1, 0100644);
 		break;
 	case GREP_SOURCE_FILE:
-		fill_filespec(df, null_sha1, 0, 0100644);
+		fill_filespec(df, &null_oid, 0, 0100644);
 		break;
 	default:
 		die("BUG: attempt to textconv something without a path?");
@@ -1396,9 +1675,17 @@ static int fill_textconv_grep(struct userdiff_driver *driver,
 	return 0;
 }
 
+static int is_empty_line(const char *bol, const char *eol)
+{
+	while (bol < eol && isspace(*bol))
+		bol++;
+	return bol == eol;
+}
+
 static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int collect_hits)
 {
 	char *bol;
+	char *peek_bol = NULL;
 	unsigned long left;
 	unsigned lno = 1;
 	unsigned last_hit = 0;
@@ -1456,7 +1743,7 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
 		case GREP_BINARY_TEXT:
 			break;
 		default:
-			die("bug: unknown binary handling mode");
+			die("BUG: unknown binary handling mode");
 		}
 	}
 
@@ -1543,8 +1830,24 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
 				show_function = 1;
 			goto next_line;
 		}
-		if (show_function && match_funcname(opt, gs, bol, eol))
-			show_function = 0;
+		if (show_function && (!peek_bol || peek_bol < bol)) {
+			unsigned long peek_left = left;
+			char *peek_eol = eol;
+
+			/*
+			 * Trailing empty lines are not interesting.
+			 * Peek past them to see if they belong to the
+			 * body of the current function.
+			 */
+			peek_bol = bol;
+			while (is_empty_line(peek_bol, peek_eol)) {
+				peek_bol = peek_eol + 1;
+				peek_eol = end_of_line(peek_bol, &peek_left);
+			}
+
+			if (match_funcname(opt, gs, peek_bol, peek_eol))
+				show_function = 0;
+		}
 		if (show_function ||
 		    (last_hit && lno <= last_hit + opt->post_context)) {
 			/* If the last hit is within the post context,
@@ -1565,7 +1868,7 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
 		return 0;
 
 	if (opt->status_only)
-		return 0;
+		return opt->unmatch_name_only;
 	if (opt->unmatch_name_only) {
 		/* We did not see any hit, so we want to show this */
 		show_name(opt, gs->name);
@@ -1587,7 +1890,7 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
 				     opt->color_filename);
 			output_sep(opt, ':');
 		}
-		snprintf(buf, sizeof(buf), "%u\n", count);
+		xsnprintf(buf, sizeof(buf), "%u\n", count);
 		opt->output(opt, buf, strlen(buf));
 		return 1;
 	}
@@ -1671,23 +1974,20 @@ void grep_source_init(struct grep_source *gs, enum grep_source_type type,
 	case GREP_SOURCE_FILE:
 		gs->identifier = xstrdup(identifier);
 		break;
-	case GREP_SOURCE_SHA1:
-		gs->identifier = xmalloc(20);
-		hashcpy(gs->identifier, identifier);
+	case GREP_SOURCE_OID:
+		gs->identifier = oiddup(identifier);
 		break;
 	case GREP_SOURCE_BUF:
 		gs->identifier = NULL;
+		break;
 	}
 }
 
 void grep_source_clear(struct grep_source *gs)
 {
-	free(gs->name);
-	gs->name = NULL;
-	free(gs->path);
-	gs->path = NULL;
-	free(gs->identifier);
-	gs->identifier = NULL;
+	FREE_AND_NULL(gs->name);
+	FREE_AND_NULL(gs->path);
+	FREE_AND_NULL(gs->identifier);
 	grep_source_clear_data(gs);
 }
 
@@ -1695,9 +1995,8 @@ void grep_source_clear_data(struct grep_source *gs)
 {
 	switch (gs->type) {
 	case GREP_SOURCE_FILE:
-	case GREP_SOURCE_SHA1:
-		free(gs->buf);
-		gs->buf = NULL;
+	case GREP_SOURCE_OID:
+		FREE_AND_NULL(gs->buf);
 		gs->size = 0;
 		break;
 	case GREP_SOURCE_BUF:
@@ -1706,7 +2005,7 @@ void grep_source_clear_data(struct grep_source *gs)
 	}
 }
 
-static int grep_source_load_sha1(struct grep_source *gs)
+static int grep_source_load_oid(struct grep_source *gs)
 {
 	enum object_type type;
 
@@ -1717,7 +2016,7 @@ static int grep_source_load_sha1(struct grep_source *gs)
 	if (!gs->buf)
 		return error(_("'%s': unable to read %s"),
 			     gs->name,
-			     sha1_to_hex(gs->identifier));
+			     oid_to_hex(gs->identifier));
 	return 0;
 }
 
@@ -1732,7 +2031,7 @@ static int grep_source_load_file(struct grep_source *gs)
 	if (lstat(filename, &st) < 0) {
 	err_ret:
 		if (errno != ENOENT)
-			error(_("'%s': %s"), filename, strerror(errno));
+			error_errno(_("failed to stat '%s'"), filename);
 		return -1;
 	}
 	if (!S_ISREG(st.st_mode))
@@ -1743,7 +2042,7 @@ static int grep_source_load_file(struct grep_source *gs)
 		goto err_ret;
 	data = xmallocz(size);
 	if (st.st_size != read_in_full(i, data, size)) {
-		error(_("'%s': short read %s"), filename, strerror(errno));
+		error_errno(_("'%s': short read"), filename);
 		close(i);
 		free(data);
 		return -1;
@@ -1763,12 +2062,12 @@ static int grep_source_load(struct grep_source *gs)
 	switch (gs->type) {
 	case GREP_SOURCE_FILE:
 		return grep_source_load_file(gs);
-	case GREP_SOURCE_SHA1:
-		return grep_source_load_sha1(gs);
+	case GREP_SOURCE_OID:
+		return grep_source_load_oid(gs);
 	case GREP_SOURCE_BUF:
 		return gs->buf ? 0 : -1;
 	}
-	die("BUG: invalid grep_source type");
+	die("BUG: invalid grep_source type to load");
 }
 
 void grep_source_load_driver(struct grep_source *gs)