Merge branch 'lo/repo-info' into seen

A new subcommand "git repo" gives users a way to grab various
repository characteristics.

* lo/repo-info:
  repo: add the --format flag
  repo: add field layout.shallow
  repo: add field layout.bare
  repo: add the field references.format
  repo: declare the repo command

Author: gitster

.gitignore

@@ -139,6 +139,7 @@
 /git-repack
 /git-replace
 /git-replay
+/git-repo
 /git-request-pull
 /git-rerere
 /git-reset

Documentation/git-repo.adoc

@@ -0,0 +1,58 @@
+git-repo(1)
+===========
+
+NAME
+----
+git-repo - Retrieve information about a repository
+
+SYNOPSIS
+--------
+[synopsis]
+git repo info [<key>...]
+
+DESCRIPTION
+-----------
+This command retrieve repository level information.
+
+THIS COMMAND IS EXPERIMENTAL. THE BEHAVIOR MAY CHANGE.
+
+COMMANDS
+--------
+info [--format=<format>] [<key>...]::
+	Retrieve metadata-related information about the current repository. Only
+	the requested data will be returned based on their keys (see "INFO KEYS"
+	section below).
++
+The output format can be chosen through the flag `--format`. Two formats are
+supported:
++
+* `keyvalue`: output key-value pairs one per line using the `=` character as
+the delimiter between the key and the value. This is the default.
+
+* `null`: similar to `keyvalue`, but using a newline character as the delimiter
+between the key and the value and using a null character after each value.
+This format is better suited for being parsed by another applications than
+`keyvalue`.
+
+INFO KEYS
+---------
+
+The set of data that `git repo` can return is grouped into the following
+categories:
+
+`references`::
+Reference-related data:
+* `format`: the reference storage format
+
+`layout`::
+Information about the how the current repository is represented:
+* `bare`: `true` if this is a bare repository, otherwise `false`.
+* `shallow`: `true` if this is a shallow repository, otherwise `false`.
+
+SEE ALSO
+--------
+linkgit:git-rev-parse[1]
+
+GIT
+---
+Part of the linkgit:git[1] suite

Documentation/meson.build

@@ -116,6 +116,7 @@ manpages = {
   'git-repack.adoc' : 1,
   'git-replace.adoc' : 1,
   'git-replay.adoc' : 1,
+  'git-repo.adoc' : 1,
   'git-request-pull.adoc' : 1,
   'git-rerere.adoc' : 1,
   'git-reset.adoc' : 1,

Makefile

@@ -1306,6 +1306,7 @@ BUILTIN_OBJS += builtin/remote.o
 BUILTIN_OBJS += builtin/repack.o
 BUILTIN_OBJS += builtin/replace.o
 BUILTIN_OBJS += builtin/replay.o
+BUILTIN_OBJS += builtin/repo.o
 BUILTIN_OBJS += builtin/rerere.o
 BUILTIN_OBJS += builtin/reset.o
 BUILTIN_OBJS += builtin/rev-list.o

builtin.h

@@ -216,6 +216,7 @@ int cmd_remote_ext(int argc, const char **argv, const char *prefix, struct repos
 int cmd_remote_fd(int argc, const char **argv, const char *prefix, struct repository *repo);
 int cmd_repack(int argc, const char **argv, const char *prefix, struct repository *repo);
 int cmd_replay(int argc, const char **argv, const char *prefix, struct repository *repo);
+int cmd_repo(int argc, const char **argv, const char *prefix, struct repository *repo);
 int cmd_rerere(int argc, const char **argv, const char *prefix, struct repository *repo);
 int cmd_reset(int argc, const char **argv, const char *prefix, struct repository *repo);
 int cmd_restore(int argc, const char **argv, const char *prefix, struct repository *repo);

builtin/repo.c

@@ -0,0 +1,154 @@
+#define USE_THE_REPOSITORY_VARIABLE
+
+#include "builtin.h"
+#include "parse-options.h"
+#include "refs.h"
+#include "environment.h"
+#include "shallow.h"
+
+typedef const char *get_value_fn(struct repository *repo);
+
+enum output_format {
+	FORMAT_KEYVALUE,
+	FORMAT_NULL_TERMINATED,
+};
+
+struct field {
+	const char *key;
+	get_value_fn *add_field_callback;
+};
+
+static const char *get_layout_bare(struct repository *repo UNUSED)
+{
+	return is_bare_repository() ? "true" : "false";
+}
+
+static const char *get_layout_shallow(struct repository *repo)
+{
+	return is_repository_shallow(repo) ? "true" : "false";
+}
+
+static const char *get_references_format(struct repository *repo)
+{
+	return ref_storage_format_to_name(repo->ref_storage_format);
+}
+
+/* repo_info_fields keys should be in lexicographical order */
+static const struct field repo_info_fields[] = {
+	{ "layout.bare", get_layout_bare },
+	{ "layout.shallow", get_layout_shallow },
+	{ "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_callback(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(struct field),
+					    repo_info_fields_cmp);
+	return found ? found->add_field_callback : NULL;
+}
+
+static int qsort_strcmp(const void *va, const void *vb)
+{
+	const char *a = *(const char **)va;
+	const char *b = *(const char **)vb;
+
+	return strcmp(a, b);
+}
+
+static int print_fields(int argc, const char **argv,
+			struct repository *repo,
+			enum output_format format)
+{
+	const char *last = "";
+	char kv_sep;
+	char field_sep;
+
+	switch (format) {
+	case FORMAT_KEYVALUE:
+		kv_sep = '=';
+		field_sep = '\n';
+		break;
+	case FORMAT_NULL_TERMINATED:
+		kv_sep = '\n';
+		field_sep = '\0';
+		break;
+	}
+
+	QSORT(argv, argc, qsort_strcmp);
+
+	for (int i = 0; i < argc; i++) {
+		get_value_fn *callback;
+		const char *key = argv[i];
+		const char *value;
+
+		if (!strcmp(key, last))
+			continue;
+
+		callback = get_value_callback(key);
+
+		if (!callback)
+			return error("key %s not found", key);
+
+		value = callback(repo);
+		printf("%s%c%s%c", key, kv_sep, value, field_sep);
+		last = key;
+	}
+
+	return 0;
+}
+
+static int repo_info(int argc, const char **argv, const char *prefix,
+		     struct repository *repo)
+{
+	const char *format_str = "keyvalue";
+	enum output_format format;
+	const char *const repo_info_usage[] = {
+		"git repo info [<key>...]",
+		NULL
+	};
+	struct option options[] = {
+		OPT_STRING(0, "format", &format_str, N_("format"),
+			   N_("output format")),
+		OPT_END()
+	};
+
+	argc = parse_options(argc, argv, prefix, options, repo_info_usage, 0);
+
+	if (!strcmp(format_str, "keyvalue"))
+		format = FORMAT_KEYVALUE;
+	else if (!strcmp(format_str, "null"))
+		format = FORMAT_NULL_TERMINATED;
+	else
+		die("invalid format %s", format_str);
+
+	return print_fields(argc, argv, repo, format);
+}
+
+int cmd_repo(int argc, const char **argv, const char *prefix,
+	     struct repository *repo)
+{
+	parse_opt_subcommand_fn *fn = NULL;
+	const char *const repo_usage[] = {
+		"git repo info [<key>...]",
+		NULL
+	};
+	struct option options[] = {
+		OPT_SUBCOMMAND("info", &fn, repo_info),
+		OPT_END()
+	};
+
+	argc = parse_options(argc, argv, prefix, options, repo_usage, 0);
+
+	return fn(argc, argv, prefix, repo);
+}

command-list.txt

@@ -164,6 +164,7 @@ git-remote                              ancillarymanipulators           complete
 git-repack                              ancillarymanipulators           complete
 git-replace                             ancillarymanipulators           complete
 git-replay                              plumbingmanipulators
+git-repo                                plumbinginterrogators
 git-request-pull                        foreignscminterface             complete
 git-rerere                              ancillaryinterrogators
 git-reset                               mainporcelain           history

git.c

@@ -611,6 +611,7 @@ static struct cmd_struct commands[] = {
 	{ "repack", cmd_repack, RUN_SETUP },
 	{ "replace", cmd_replace, RUN_SETUP },
 	{ "replay", cmd_replay, RUN_SETUP },
+	{ "repo", cmd_repo, RUN_SETUP },
 	{ "rerere", cmd_rerere, RUN_SETUP },
 	{ "reset", cmd_reset, RUN_SETUP },
 	{ "restore", cmd_restore, RUN_SETUP | NEED_WORK_TREE },

meson.build

@@ -645,6 +645,7 @@ builtin_sources = [
   'builtin/repack.c',
   'builtin/replace.c',
   'builtin/replay.c',
+  'builtin/repo.c',
   'builtin/rerere.c',
   'builtin/reset.c',
   'builtin/rev-list.c',

t/meson.build

@@ -231,6 +231,7 @@ integration_tests = [
   't1700-split-index.sh',
   't1701-racy-split-index.sh',
   't1800-hook.sh',
+  't1900-repo.sh',
   't2000-conflict-when-checking-files-out.sh',
   't2002-checkout-cache-u.sh',
   't2003-checkout-cache-mkdir.sh',