[PATCH] pretty: colorize pattern matches in commit messages

[Hamza Mahfooz <someguy@effective-light.com>]

Currently, for example when

  git log --grep=pattern

is executed, the outputted commits that are matched by the pattern do not
have the relevant substring matches highlighted.

Signed-off-by: Hamza Mahfooz <someguy@effective-light.com>
---
 pretty.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 98 insertions(+), 11 deletions(-)

diff --git a/pretty.c b/pretty.c
index 9631529c10..2886916ae6 100644
--- a/pretty.c
+++ b/pretty.c
@@ -431,15 +431,80 @@ const char *show_ident_date(const struct ident_split *ident,
 	return show_date(date, tz, mode);
 }
 
+static void append_matched_line(struct grep_opt *opt, const char *line,
+				size_t linelen, enum grep_pat_token token,
+				int field, struct strbuf *sb)
+{
+	struct grep_pat *pat;
+	struct strbuf tmp_sb;
+	regmatch_t tmp_match, match;
+	char *buf, *eol, *color;
+	int cflags = 0;
+
+	strbuf_init(&tmp_sb, linelen + 1);
+	strbuf_add(&tmp_sb, line, linelen);
+	buf = tmp_sb.buf;
+	eol = buf + linelen;
+
+	if (!opt || !want_color(opt->color))
+		goto skip;
+
+	color = opt->colors[GREP_COLOR_MATCH_CONTEXT];
+
+	for (;;) {
+		match.rm_so = match.rm_eo = -1;
+
+		for (pat = (token == GREP_PATTERN_HEAD ?
+			    opt->header_list : opt->pattern_list);
+		     pat; pat = pat->next) {
+			if (pat->token == token &&
+			    (field == -1 || pat->field == field) &&
+			    !regexec(&pat->regexp, buf, 1, &tmp_match,
+				     cflags)) {
+
+				if ((match.rm_so >= 0 && match.rm_eo >= 0) &&
+				    (tmp_match.rm_so > match.rm_so ||
+				     (tmp_match.rm_so == match.rm_so &&
+				      tmp_match.rm_eo < match.rm_eo)))
+					continue;
+
+				match.rm_so = tmp_match.rm_so;
+				match.rm_eo = tmp_match.rm_eo;
+			}
+		}
+
+		if (match.rm_so == match.rm_eo)
+			break;
+
+		strbuf_grow(sb, strlen(color) + strlen(GIT_COLOR_RESET));
+		strbuf_add(sb, buf, match.rm_so);
+		strbuf_add(sb, color, strlen(color));
+		strbuf_add(sb, buf + match.rm_so,
+			   match.rm_eo - match.rm_so);
+		strbuf_add(sb, GIT_COLOR_RESET,
+			   strlen(GIT_COLOR_RESET));
+		buf += match.rm_eo;
+		cflags = REG_NOTBOL;
+	}
+
+skip:
+	strbuf_add(sb, buf, eol - buf);
+
+	strbuf_release(&tmp_sb);
+}
+
 void pp_user_info(struct pretty_print_context *pp,
 		  const char *what, struct strbuf *sb,
 		  const char *line, const char *encoding)
 {
+	struct strbuf id;
 	struct ident_split ident;
 	char *line_end;
 	const char *mailbuf, *namebuf;
 	size_t namelen, maillen;
 	int max_length = 78; /* per rfc2822 */
+	int field = -1;
+	struct grep_opt *opt = pp->rev ? &pp->rev->grep_filter : NULL;
 
 	if (pp->fmt == CMIT_FMT_ONELINE)
 		return;
@@ -496,9 +561,22 @@ void pp_user_info(struct pretty_print_context *pp,
 			strbuf_addch(sb, '\n');
 		strbuf_addf(sb, " <%.*s>\n", (int)maillen, mailbuf);
 	} else {
-		strbuf_addf(sb, "%s: %.*s%.*s <%.*s>\n", what,
-			    (pp->fmt == CMIT_FMT_FULLER) ? 4 : 0, "    ",
-			    (int)namelen, namebuf, (int)maillen, mailbuf);
+		strbuf_init(&id, namelen + maillen + 4);
+
+		if (!strcmp(what, "Author"))
+			field = GREP_HEADER_AUTHOR;
+		else if (!strcmp(what, "Commit"))
+			field = GREP_HEADER_COMMITTER;
+
+		strbuf_addf(sb, "%s: %.*s", what,
+			    (pp->fmt == CMIT_FMT_FULLER) ? 4 : 0, "    ");
+		strbuf_addf(&id, "%.*s <%.*s>", (int)namelen, namebuf,
+			    (int)maillen, mailbuf);
+
+		append_matched_line(opt, id.buf, id.len,
+				    GREP_PATTERN_HEAD, field, sb);
+		strbuf_addch(sb, '\n');
+		strbuf_release(&id);
 	}
 
 	switch (pp->fmt) {
@@ -1855,6 +1933,7 @@ static void pp_header(struct pretty_print_context *pp,
 	}
 }
 
+
 void pp_title_line(struct pretty_print_context *pp,
 		   const char **msg_p,
 		   struct strbuf *sb,
@@ -1935,8 +2014,8 @@ static int pp_utf8_width(const char *start, const char *end)
 	return width;
 }
 
-static void strbuf_add_tabexpand(struct strbuf *sb, int tabwidth,
-				 const char *line, int linelen)
+static void strbuf_add_tabexpand(struct grep_opt *opt, struct strbuf *sb,
+				 int tabwidth, const char *line, int linelen)
 {
 	const char *tab;
 
@@ -1953,7 +2032,8 @@ static void strbuf_add_tabexpand(struct strbuf *sb, int tabwidth,
 			break;
 
 		/* Output the data .. */
-		strbuf_add(sb, line, tab - line);
+		append_matched_line(opt, line, tab - line, GREP_PATTERN_BODY,
+				    -1, sb);
 
 		/* .. and the de-tabified tab */
 		strbuf_addchars(sb, ' ', tabwidth - (width % tabwidth));
@@ -1968,7 +2048,8 @@ static void strbuf_add_tabexpand(struct strbuf *sb, int tabwidth,
 	 * worrying about width - there's nothing more to
 	 * align.
 	 */
-	strbuf_add(sb, line, linelen);
+	append_matched_line(opt, line, linelen,
+			    GREP_PATTERN_BODY, -1, sb);
 }
 
 /*
@@ -1980,11 +2061,14 @@ static void pp_handle_indent(struct pretty_print_context *pp,
 			     struct strbuf *sb, int indent,
 			     const char *line, int linelen)
 {
+	struct grep_opt *opt = pp->rev ? &pp->rev->grep_filter : NULL;
+
 	strbuf_addchars(sb, ' ', indent);
 	if (pp->expand_tabs_in_log)
-		strbuf_add_tabexpand(sb, pp->expand_tabs_in_log, line, linelen);
+		strbuf_add_tabexpand(opt, sb, pp->expand_tabs_in_log, line, linelen);
 	else
-		strbuf_add(sb, line, linelen);
+		append_matched_line(opt, line, linelen, GREP_PATTERN_BODY, -1,
+				    sb);
 }
 
 static int is_mboxrd_from(const char *line, int len)
@@ -2002,7 +2086,9 @@ void pp_remainder(struct pretty_print_context *pp,
 		  struct strbuf *sb,
 		  int indent)
 {
+	struct grep_opt *opt = pp->rev ? &pp->rev->grep_filter : NULL;
 	int first = 1;
+
 	for (;;) {
 		const char *line = *msg_p;
 		int linelen = get_one_line(line);
@@ -2023,14 +2109,15 @@ void pp_remainder(struct pretty_print_context *pp,
 		if (indent)
 			pp_handle_indent(pp, sb, indent, line, linelen);
 		else if (pp->expand_tabs_in_log)
-			strbuf_add_tabexpand(sb, pp->expand_tabs_in_log,
+			strbuf_add_tabexpand(opt, sb, pp->expand_tabs_in_log,
 					     line, linelen);
 		else {
 			if (pp->fmt == CMIT_FMT_MBOXRD &&
 					is_mboxrd_from(line, linelen))
 				strbuf_addch(sb, '>');
 
-			strbuf_add(sb, line, linelen);
+			append_matched_line(opt, line, linelen,
+					    GREP_PATTERN_BODY, -1, sb);
 		}
 		strbuf_addch(sb, '\n');
 	}
-- 
2.33.0