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[PATCH v5 2/2] pretty: colorize pattern matches in commit messages

From
Hamza Mahfooz <someguy@effective-light.com>
Date
Sep 16, 2021, 14:09 UTC
Message-ID
<20210916140943.2442184-2-someguy@effective-light.com>
In-Reply-To
<20210916140943.2442184-1-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.
---
 Documentation/git-log.txt |   8 +++
 pretty.c                  | 110 +++++++++++++++++++++++++++++++++-----
 t/t4202-log.sh            |  55 +++++++++++++++++++
 3 files changed, 161 insertions(+), 12 deletions(-)
diff --git a/Documentation/git-log.txt b/Documentation/git-log.txt
index 0498e7bacb..c689f7d235 100644
--- a/Documentation/git-log.txt
+++ b/Documentation/git-log.txt
@@ -241,6 +241,14 @@ This setting can be disabled by the `--no-notes` option,
 overridden by the `GIT_NOTES_DISPLAY_REF` environment variable,
 and overridden by the `--notes=<ref>` option.
 
+color.grep.selected::
+	Determines the non matching text (background) color of selected lines,
+	when `--grep`, `--author` or `--committer` are used.
+
+color.grep.matchSelected::
+	Determines the matching text (foreground) color of selected lines, when
+	`--grep`, `--author` or `--committer` are used.
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/pretty.c b/pretty.c
index 73b5ead509..77969a623b 100644
--- a/pretty.c
+++ b/pretty.c
@@ -431,15 +431,74 @@ 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_add(sb, color, strlen(color));
+	strbuf_add(sb, buf, buflen);
+	if (strlen(color))
+		strbuf_add(sb, GIT_COLOR_RESET, strlen(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;
+	struct strbuf tmp_sb;
+	int eflags = 0;
+
+	if (!opt || !want_color(color) || opt->invert) {
+		strbuf_add(sb, line, linelen);
+		return;
+	}
+
+	strbuf_init(&tmp_sb, linelen + 1);
+	strbuf_add(&tmp_sb, line, linelen);
+
+	buf = tmp_sb.buf;
+	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 (buf != line) {
+		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);
+	}
+
+	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 */
+	enum grep_header_field field = GREP_HEADER_FIELD_MAX;
+	struct grep_opt *opt = pp->rev ? &pp->rev->grep_filter : NULL;
 
 	if (pp->fmt == CMIT_FMT_ONELINE)
 		return;
@@ -496,9 +555,22 @@ 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_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 +2011,9 @@ 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 +2030,9 @@ 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 +2047,8 @@ 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 +2060,16 @@ 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 +2087,9 @@ 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 +2110,17 @@ 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..943c00e338 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -449,6 +449,61 @@ test_expect_success !FAIL_PREREQS 'log with various grep.patternType configurati
 	)
 '
 
+cat > expect << EOF
+Author: <BOLD;RED>A U<RESET> Thor <author@example.com>
+EOF
+
+test_expect_success 'log --author' '
+	git log -1 --color=always --author="A U" >log &&
+	grep Author log >actual.raw &&
+	test_decode_color <actual.raw >actual &&
+	test_cmp expect actual
+'
+
+cat > expect << EOF
+Commit:     C O Mitter <committer@<BOLD;RED>example<RESET>.com>
+EOF
+
+test_expect_success 'log --committer' '
+	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
+'
+
+cat > expect << EOF
+    <BOLD;RED>Sec<RESET>ond
+    <BOLD;RED>sec<RESET>ond
+EOF
+
+test_expect_success 'log -i --grep with color' '
+	git log --color=always -i --grep=sec >log &&
+	grep -i sec log >actual.raw &&
+	test_decode_color <actual.raw >actual &&
+	test_cmp expect actual
+'
+cat > expect << EOF
+    <GREEN>th<RESET><BOLD;RED>ir<RESET><GREEN>d<RESET>
+EOF
+
+test_expect_success '-c color.grep.selected log --grep' '
+	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
+'
+
+cat > expect << EOF
+    <BLUE>i<RESET>n<BLUE>i<RESET>t<BLUE>i<RESET>al
+EOF
+
+test_expect_success '-c color.grep.matchSelected log --grep' '
+	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: Eric Sunshine
Message 2 of 6 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 16, 2021
  2. 2/2 pretty: colorize pattern matches in commit messagesHamza Mahfooz, Sep 16, 2021
  3. Eric SunshineSep 17, 2021
  4. Hamza MahfoozSep 17, 2021
  5. Jeff KingSep 17, 2021
  6. Eric SunshineSep 17, 2021

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

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