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[PATCH v6 2/2] pretty: colorize pattern matches in commit messages

From
Hamza Mahfooz <someguy@effective-light.com>
Date
Sep 21, 2021, 00:30 UTC
Message-ID
<20210921003050.641393-2-someguy@effective-light.com>
In-Reply-To
<20210921003050.641393-1-someguy@effective-light.com>

The "git log" command limits its output to the commits that contain strings matched by a pattern when the "--grep=<pattern>" option is used, but unlike output from "git grep -e <pattern>", the matches are not highlighted, making them harder to spot.

Teach the pretty-printer code to highlight matches from the "--grep=<pattern>", "--author=<pattern>" and "--committer=<pattern>" options (to view the last one, you may have to ask for --pretty=fuller).

Also, it must be noted that we are effectively greping the content twice, however it only slows down "git log --author=^H" on this repository by around 1-2% (compared to v2.33.0), so it should be a small enough slow down to justify the addition of the feature.

Signed-off-by: Hamza Mahfooz <someguy@effective-light.com>
---
v2: make the commit message whole (add the missing ingredients), rename
    append_matched_line() to append_line_with_color(), use
    colors[GREP_COLOR_MATCH_SELECTED] instead of
    colors[GREP_COLOR_MATCH_CONTEXT], allow the background color to be
    customized, don't copy strings to a buffer when not coloring in
    append_line_with_color(), rename next_match() to grep_next_match(),
    repurpose grep_next_match()/match_one_pattern() for use in
    append_line_with_color() (allowing us to remove duplicated matching
    code in append_line_with_color()), document how to customize the
    feature and modify some of the tests to fit the feature better.
v3: fix a formatting issue with the added documentation.
v4: add strbuf_add_with_color(), use the correct color code scheme in the
    unit tests and add more unit tests.
v5: separate grep changes from pretty changes and add some performance
    analysis in the commit message.
v6: put the documentation in the correct place, cleanup pretty.c and
    format the unit tests according to the current convention.
---
 Documentation/config/color.txt |   7 ++-
 pretty.c                       | 107 +++++++++++++++++++++++++++++----
 t/t4202-log.sh                 |  51 ++++++++++++++++
 3 files changed, 151 insertions(+), 14 deletions(-)
diff --git a/Documentation/config/color.txt b/Documentation/config/color.txt
index e05d520a86..91d9a9da32 100644
--- a/Documentation/config/color.txt
+++ b/Documentation/config/color.txt
@@ -104,9 +104,12 @@ color.grep.<slot>::
 `matchContext`;;
 	matching text in context lines
 `matchSelected`;;
-	matching text in selected lines
+	matching text in selected lines. Also, used to customize the following
+	linkgit:git-log[1] subcommands: `--grep`, `--author` and `--committer`.
 `selected`;;
-	non-matching text in selected lines
+	non-matching text in selected lines. Also, used to customize the
+	following linkgit:git-log[1] subcommands: `--grep`, `--author` and
+	`--committer`.
 `separator`;;
 	separators between fields on a line (`:`, `-`, and `=`)
 	and between hunks (`--`)
diff --git a/pretty.c b/pretty.c
index 73b5ead509..943a2d2ee2 100644
--- a/pretty.c
+++ b/pretty.c
@@ -431,6 +431,56 @@ const char *show_ident_date(const struct ident_split *ident,
 	return show_date(date, tz, mode);
 }
 
+static inline void strbuf_add_with_color(struct strbuf *sb, const char *color,
+					 char *buf, size_t buflen)
+{
+	strbuf_addstr(sb, color);
+	strbuf_add(sb, buf, buflen);
+	if (*color)
+		strbuf_addstr(sb, GIT_COLOR_RESET);
+}
+
+static void append_line_with_color(struct strbuf *sb, struct grep_opt *opt,
+				   const char *line, size_t linelen,
+				   int color, enum grep_context ctx,
+				   enum grep_header_field field)
+{
+	char *buf, *eol;
+	const char *line_color, *match_color;
+	regmatch_t match;
+	int eflags = 0;
+
+	if (!opt || !want_color(color) || opt->invert) {
+		strbuf_add(sb, line, linelen);
+		return;
+	}
+
+	buf = (char *)line;
+	eol = buf + linelen;
+
+	line_color = opt->colors[GREP_COLOR_SELECTED];
+	match_color = opt->colors[GREP_COLOR_MATCH_SELECTED];
+
+	while (grep_next_match(opt, buf, eol, ctx, &match, field, eflags)) {
+		if (match.rm_so == match.rm_eo)
+			break;
+
+		strbuf_grow(sb, strlen(line_color) + strlen(match_color) +
+			    (2 * strlen(GIT_COLOR_RESET)));
+		strbuf_add_with_color(sb, line_color, buf, match.rm_so);
+		strbuf_add_with_color(sb, match_color, buf + match.rm_so,
+				      match.rm_eo - match.rm_so);
+		buf += match.rm_eo;
+		eflags = REG_NOTBOL;
+	}
+
+	if (eflags) {
+		strbuf_grow(sb, strlen(line_color) + strlen(GIT_COLOR_RESET));
+		strbuf_add_with_color(sb, line_color, buf, eol - buf);
+	} else
+		strbuf_add(sb, buf, eol - buf);
+}
+
 void pp_user_info(struct pretty_print_context *pp,
 		  const char *what, struct strbuf *sb,
 		  const char *line, const char *encoding)
@@ -496,9 +546,28 @@ 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);
+		struct strbuf id;
+		enum grep_header_field field = GREP_HEADER_FIELD_MAX;
+		struct grep_opt *opt = pp->rev ? &pp->rev->grep_filter : NULL;
+
+		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: ", what);
+		if (pp->fmt == CMIT_FMT_FULLER)
+			strbuf_addchars(sb, ' ', 4);
+
+		strbuf_addf(&id, "%.*s <%.*s>", (int)namelen, namebuf,
+			    (int)maillen, mailbuf);
+
+		append_line_with_color(sb, opt, id.buf, id.len, pp->color,
+				       GREP_CONTEXT_HEAD, field);
+		strbuf_addch(sb, '\n');
+		strbuf_release(&id);
 	}
 
 	switch (pp->fmt) {
@@ -1939,8 +2008,9 @@ 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 strbuf *sb, struct grep_opt *opt,
+				 int color, int tabwidth, const char *line,
+				 int linelen)
 {
 	const char *tab;
 
@@ -1957,7 +2027,9 @@ static void strbuf_add_tabexpand(struct strbuf *sb, int tabwidth,
 			break;
 
 		/* Output the data .. */
-		strbuf_add(sb, line, tab - line);
+		append_line_with_color(sb, opt, line, tab - line, color,
+				       GREP_CONTEXT_BODY,
+				       GREP_HEADER_FIELD_MAX);
 
 		/* .. and the de-tabified tab */
 		strbuf_addchars(sb, ' ', tabwidth - (width % tabwidth));
@@ -1972,7 +2044,8 @@ 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_line_with_color(sb, opt, line, linelen, color, GREP_CONTEXT_BODY,
+			       GREP_HEADER_FIELD_MAX);
 }
 
 /*
@@ -1984,11 +2057,16 @@ 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(sb, opt, pp->color, pp->expand_tabs_in_log,
+				     line, linelen);
 	else
-		strbuf_add(sb, line, linelen);
+		append_line_with_color(sb, opt, line, linelen, pp->color,
+				       GREP_CONTEXT_BODY,
+				       GREP_HEADER_FIELD_MAX);
 }
 
 static int is_mboxrd_from(const char *line, int len)
@@ -2006,7 +2084,9 @@ 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);
@@ -2027,14 +2107,17 @@ 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,
-					     line, linelen);
+			strbuf_add_tabexpand(sb, opt, pp->color,
+					     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_line_with_color(sb, opt, line, linelen,
+					       pp->color, GREP_CONTEXT_BODY,
+					       GREP_HEADER_FIELD_MAX);
 		}
 		strbuf_addch(sb, '\n');
 	}
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index 9dfead936b..3d240bba57 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -449,6 +449,57 @@ test_expect_success !FAIL_PREREQS 'log with various grep.patternType configurati
 	)
 '
 
+test_expect_success 'log --author' '
+	cat >expect <<-\EOF &&
+	Author: <BOLD;RED>A U<RESET> Thor <author@example.com>
+	EOF
+	git log -1 --color=always --author="A U" >log &&
+	grep Author log >actual.raw &&
+	test_decode_color <actual.raw >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'log --committer' '
+	cat >expect <<-\EOF &&
+	Commit:     C O Mitter <committer@<BOLD;RED>example<RESET>.com>
+	EOF
+	git log -1 --color=always --pretty=fuller --committer="example" >log &&
+	grep "Commit:" log >actual.raw &&
+	test_decode_color <actual.raw >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'log -i --grep with color' '
+	cat >expect <<-\EOF &&
+	    <BOLD;RED>Sec<RESET>ond
+	    <BOLD;RED>sec<RESET>ond
+	EOF
+	git log --color=always -i --grep=^sec >log &&
+	grep -i sec log >actual.raw &&
+	test_decode_color <actual.raw >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '-c color.grep.selected log --grep' '
+	cat >expect <<-\EOF &&
+	    <GREEN>th<RESET><BOLD;RED>ir<RESET><GREEN>d<RESET>
+	EOF
+	git -c color.grep.selected="green" log --color=always --grep=ir >log &&
+	grep ir log >actual.raw &&
+	test_decode_color <actual.raw >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '-c color.grep.matchSelected log --grep' '
+	cat >expect <<-\EOF &&
+	    <BLUE>i<RESET>n<BLUE>i<RESET>t<BLUE>i<RESET>al
+	EOF
+	git -c color.grep.matchSelected="blue" log --color=always --grep=i >log &&
+	grep al log >actual.raw &&
+	test_decode_color <actual.raw >actual &&
+	test_cmp expect actual
+'
+
 cat > expect <<EOF
 * Second
 * sixth

-- 
2.33.0
Previous: Hamza MahfoozNext: Jeff King
Message 2 of 10 in “grep: refactor next_match() and match_one_pattern() for external use”
  1. 1/2 grep: refactor next_match() and match_one_pattern() for external useHamza Mahfooz, Sep 21, 2021
  2. 2/2 pretty: colorize pattern matches in commit messagesHamza Mahfooz, Sep 21, 2021
  3. Jeff KingSep 21, 2021
  4. Jeff KingSep 21, 2021
  5. 1/2 grep: stop modifying buffer in strip_timestampJeff King, Sep 21, 2021
  6. 2/2 grep: mark "haystack" buffers as constJeff King, Sep 21, 2021
  7. Jeff KingSep 21, 2021
  8. Hamza MahfoozSep 21, 2021
  9. Jeff KingSep 21, 2021
  10. Jeff KingSep 21, 2021

Read the whole thread, see it on lore, or plain text.

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