grep: use designated initializers for grep_defaults

In 15fabd1 ("builtin/grep.c: make configuration callback more
reusable", 2012-10-09), we learned to fill a `static struct grep_opt
grep_defaults` which we can use as a blueprint for other such structs.

At the time, we didn't consider designated initializers to be widely
useable, but these days, we do. (See, e.g., cbc0f81 ("strbuf: use
designated initializers in STRBUF_INIT", 2017-07-10).)

Use designated initializers to let the compiler set up the struct and so
that we don't need to remember to call `init_grep_defaults()`.

Signed-off-by: Martin Ågren <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: Martin Ågren

Documentation/MyFirstObjectWalk.txt

@@ -388,17 +388,9 @@ Next, let's try to filter the commits we see based on their author. This is
 equivalent to running `git log --author=<pattern>`. We can add a filter by
 modifying `rev_info.grep_filter`, which is a `struct grep_opt`.
 
-First some setup. Add `init_grep_defaults()` to `init_walken_defaults()` and add
-`grep_config()` to `git_walken_config()`:
+First some setup. Add `grep_config()` to `git_walken_config()`:
 
 ----
-static void init_walken_defaults(void)
-{
-	init_grep_defaults();
-}
-
-...
-
 static int git_walken_config(const char *var, const char *value, void *cb)
 {
 	grep_config(var, value, cb);

builtin/grep.c

@@ -950,7 +950,6 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
-	init_grep_defaults();
 	git_config(grep_cmd_config, NULL);
 	grep_init(&opt, the_repository, prefix);
 

builtin/log.c

@@ -131,7 +131,6 @@ static int log_line_range_callback(const struct option *option, const char *arg,
 
 static void init_log_defaults(void)
 {
-	init_grep_defaults();
 	init_diff_ui_defaults();
 
 	decoration_style = auto_decoration_style();

grep.c

@@ -14,7 +14,31 @@ static int grep_source_load(struct grep_source *gs);
 static int grep_source_is_binary(struct grep_source *gs,
 				 struct index_state *istate);
 
-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);
+}
+
+static struct grep_opt grep_defaults = {
+	.relative = 1,
+	.pathname = 1,
+	.max_depth = -1,
+	.pattern_type_option = GREP_PATTERN_TYPE_UNSPECIFIED,
+	.colors = {
+		[GREP_COLOR_CONTEXT] = "",
+		[GREP_COLOR_FILENAME] = "",
+		[GREP_COLOR_FUNCTION] = "",
+		[GREP_COLOR_LINENO] = "",
+		[GREP_COLOR_COLUMNNO] = "",
+		[GREP_COLOR_MATCH_CONTEXT] = GIT_COLOR_BOLD_RED,
+		[GREP_COLOR_MATCH_SELECTED] = GIT_COLOR_BOLD_RED,
+		[GREP_COLOR_SELECTED] = "",
+		[GREP_COLOR_SEP] = GIT_COLOR_CYAN,
+	},
+	.only_matching = 0,
+	.color = -1,
+	.output = std_output,
+};
 
 #ifdef USE_LIBPCRE2
 static pcre2_general_context *pcre2_global_context;
@@ -42,49 +66,11 @@ static const char *color_grep_slots[] = {
 	[GREP_COLOR_SEP]	    = "separator",
 };
 
-static void std_output(struct grep_opt *opt, const void *buf, size_t size)
-{
-	fwrite(buf, size, 1, stdout);
-}
-
 static void color_set(char *dst, const char *color_bytes)
 {
 	xsnprintf(dst, COLOR_MAXLEN, "%s", color_bytes);
 }
 
-/*
- * Initialize the grep_defaults template with hardcoded defaults.
- * We could let the compiler do this, but without C99 initializers
- * the code gets unwieldy and unreadable, so...
- */
-void init_grep_defaults(void)
-{
-	struct grep_opt *opt = &grep_defaults;
-	static int run_once;
-
-	if (run_once)
-		return;
-	run_once++;
-
-	memset(opt, 0, sizeof(*opt));
-	opt->relative = 1;
-	opt->pathname = 1;
-	opt->max_depth = -1;
-	opt->pattern_type_option = GREP_PATTERN_TYPE_UNSPECIFIED;
-	color_set(opt->colors[GREP_COLOR_CONTEXT], "");
-	color_set(opt->colors[GREP_COLOR_FILENAME], "");
-	color_set(opt->colors[GREP_COLOR_FUNCTION], "");
-	color_set(opt->colors[GREP_COLOR_LINENO], "");
-	color_set(opt->colors[GREP_COLOR_COLUMNNO], "");
-	color_set(opt->colors[GREP_COLOR_MATCH_CONTEXT], GIT_COLOR_BOLD_RED);
-	color_set(opt->colors[GREP_COLOR_MATCH_SELECTED], GIT_COLOR_BOLD_RED);
-	color_set(opt->colors[GREP_COLOR_SELECTED], "");
-	color_set(opt->colors[GREP_COLOR_SEP], GIT_COLOR_CYAN);
-	opt->only_matching = 0;
-	opt->color = -1;
-	opt->output = std_output;
-}
-
 static int parse_pattern_type_arg(const char *opt, const char *arg)
 {
 	if (!strcmp(arg, "default"))

grep.h

@@ -170,7 +170,6 @@ struct grep_opt {
 	void *output_priv;
 };
 
-void init_grep_defaults(void);
 int grep_config(const char *var, const char *value, void *);
 void grep_init(struct grep_opt *, struct repository *repo, const char *prefix);
 void grep_destroy(void);

revision.c

@@ -1834,7 +1834,6 @@ void repo_init_revisions(struct repository *r,
 	revs->commit_format = CMIT_FMT_DEFAULT;
 	revs->expand_tabs_in_log_default = 8;
 
-	init_grep_defaults();
 	grep_init(&revs->grep_filter, revs->repo, prefix);
 	revs->grep_filter.status_only = 1;