repo: add the field references.format

This commit is part of the series that introduces the new subcommand
git-repo-info.

The flag `--show-ref-format` from git-rev-parse is used for retrieving
the reference format (i.e. `files` or `reftable`). This way, it is
used for querying repository metadata, fitting in the purpose of
git-repo-info.

Add a new field `references.format` to the repo-info subcommand
containing that information.

Helped-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Justin Tobler <jltobler@gmail.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Mentored-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Lucas Seiki Oshiro <lucasseikioshiro@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 72 insertions, 2 deletions

diff --git a/builtin/repo.c b/builtin/repo.c
index fd2a9b4216..73d4e27a16 100644
--- a/builtin/repo.c
+++ b/builtin/repo.c
@@ -1,17 +1,87 @@
 #include "builtin.h"
 #include "parse-options.h"
+#include "quote.h"
+#include "refs.h"
+#include "strbuf.h"
 
 static const char *const repo_usage[] = {
 	"git repo info [<key>...]",
 	NULL
 };
 
-static int repo_info(int argc UNUSED, const char **argv UNUSED,
-		     const char *prefix UNUSED, struct repository *repo UNUSED)
+typedef int get_value_fn(struct repository *repo, struct strbuf *buf);
+
+struct field {
+	const char *key;
+	get_value_fn *get_value;
+};
+
+static int get_references_format(struct repository *repo, struct strbuf *buf)
 {
+	strbuf_addstr(buf,
+		      ref_storage_format_to_name(repo->ref_storage_format));
 	return 0;
 }
 
+/* repo_info_fields keys must be in lexicographical order */
+static const struct field repo_info_fields[] = {
+	{ "references.format", get_references_format },
+};
+
+static int repo_info_fields_cmp(const void *va, const void *vb)
+{
+	const struct field *a = va;
+	const struct field *b = vb;
+
+	return strcmp(a->key, b->key);
+}
+
+static get_value_fn *get_value_fn_for_key(const char *key)
+{
+	const struct field search_key = { key, NULL };
+	const struct field *found = bsearch(&search_key, repo_info_fields,
+					    ARRAY_SIZE(repo_info_fields),
+					    sizeof(*found),
+					    repo_info_fields_cmp);
+	return found ? found->get_value : NULL;
+}
+
+static int print_fields(int argc, const char **argv, struct repository *repo)
+{
+	int ret = 0;
+	struct strbuf valbuf = STRBUF_INIT;
+	struct strbuf quotbuf = STRBUF_INIT;
+
+	for (int i = 0; i < argc; i++) {
+		get_value_fn *get_value;
+		const char *key = argv[i];
+
+		get_value = get_value_fn_for_key(key);
+
+		if (!get_value) {
+			ret = error(_("key '%s' not found"), key);
+			continue;
+		}
+
+		strbuf_reset(&valbuf);
+		strbuf_reset(&quotbuf);
+
+		get_value(repo, &valbuf);
+		quote_c_style(valbuf.buf, &quotbuf, NULL, 0);
+		printf("%s=%s\n", key, quotbuf.buf);
+	}
+
+	strbuf_release(&valbuf);
+	strbuf_release(&quotbuf);
+	return ret;
+}
+
+static int repo_info(int argc, const char **argv, const char *prefix UNUSED,
+		     struct repository *repo)
+{
+	return print_fields(argc - 1, argv + 1, repo);
+}
+
 int cmd_repo(int argc, const char **argv, const char *prefix,
 	     struct repository *repo)
 {