1 files changed, 250 insertions, 0 deletions
diff --git a/builtin/show-ref.c b/builtin/show-ref.c
new file mode 100644
index 0000000000..45f0340c3e
--- /dev/null
+++ b/builtin/show-ref.c
@@ -0,0 +1,250 @@
+#include "builtin.h"
+#include "cache.h"
+#include "refs.h"
+#include "object.h"
+#include "tag.h"
+#include "string-list.h"
+#include "parse-options.h"
+
+static const char * const show_ref_usage[] = {
+	"git show-ref [-q|--quiet] [--verify] [--head] [-d|--dereference] [-s|--hash[=<n>]] [--abbrev[=<n>]] [--tags] [--heads] [--] [pattern*] ",
+	"git show-ref --exclude-existing[=pattern] < ref-list",
+	NULL
+};
+
+static int deref_tags, show_head, tags_only, heads_only, found_match, verify,
+	   quiet, hash_only, abbrev, exclude_arg;
+static const char **pattern;
+static const char *exclude_existing_arg;
+
+static void show_one(const char *refname, const unsigned char *sha1)
+{
+	const char *hex = find_unique_abbrev(sha1, abbrev);
+	if (hash_only)
+		printf("%s\n", hex);
+	else
+		printf("%s %s\n", hex, refname);
+}
+
+static int show_ref(const char *refname, const unsigned char *sha1, int flag, void *cbdata)
+{
+	struct object *obj;
+	const char *hex;
+	unsigned char peeled[20];
+
+	if (tags_only || heads_only) {
+		int match;
+
+		match = heads_only && !prefixcmp(refname, "refs/heads/");
+		match |= tags_only && !prefixcmp(refname, "refs/tags/");
+		if (!match)
+			return 0;
+	}
+	if (pattern) {
+		int reflen = strlen(refname);
+		const char **p = pattern, *m;
+		while ((m = *p++) != NULL) {
+			int len = strlen(m);
+			if (len > reflen)
+				continue;
+			if (memcmp(m, refname + reflen - len, len))
+				continue;
+			if (len == reflen)
+				goto match;
+			/* "--verify" requires an exact match */
+			if (verify)
+				continue;
+			if (refname[reflen - len - 1] == '/')
+				goto match;
+		}
+		return 0;
+	}
+
+match:
+	found_match++;
+
+	/* This changes the semantics slightly that even under quiet we
+	 * detect and return error if the repository is corrupt and
+	 * ref points at a nonexistent object.
+	 */
+	if (!has_sha1_file(sha1))
+		die("git show-ref: bad ref %s (%s)", refname,
+		    sha1_to_hex(sha1));
+
+	if (quiet)
+		return 0;
+
+	show_one(refname, sha1);
+
+	if (!deref_tags)
+		return 0;
+
+	if ((flag & REF_ISPACKED) && !peel_ref(refname, peeled)) {
+		if (!is_null_sha1(peeled)) {
+			hex = find_unique_abbrev(peeled, abbrev);
+			printf("%s %s^{}\n", hex, refname);
+		}
+	}
+	else {
+		obj = parse_object(sha1);
+		if (!obj)
+			die("git show-ref: bad ref %s (%s)", refname,
+			    sha1_to_hex(sha1));
+		if (obj->type == OBJ_TAG) {
+			obj = deref_tag(obj, refname, 0);
+			if (!obj)
+				die("git show-ref: bad tag at ref %s (%s)", refname,
+				    sha1_to_hex(sha1));
+			hex = find_unique_abbrev(obj->sha1, abbrev);
+			printf("%s %s^{}\n", hex, refname);
+		}
+	}
+	return 0;
+}
+
+static int add_existing(const char *refname, const unsigned char *sha1, int flag, void *cbdata)
+{
+	struct string_list *list = (struct string_list *)cbdata;
+	string_list_insert(list, refname);
+	return 0;
+}
+
+/*
+ * read "^(?:<anything>\s)?<refname>(?:\^\{\})?$" from the standard input,
+ * and
+ * (1) strip "^{}" at the end of line if any;
+ * (2) ignore if match is provided and does not head-match refname;
+ * (3) warn if refname is not a well-formed refname and skip;
+ * (4) ignore if refname is a ref that exists in the local repository;
+ * (5) otherwise output the line.
+ */
+static int exclude_existing(const char *match)
+{
+	static struct string_list existing_refs = STRING_LIST_INIT_NODUP;
+	char buf[1024];
+	int matchlen = match ? strlen(match) : 0;
+
+	for_each_ref(add_existing, &existing_refs);
+	while (fgets(buf, sizeof(buf), stdin)) {
+		char *ref;
+		int len = strlen(buf);
+
+		if (len > 0 && buf[len - 1] == '\n')
+			buf[--len] = '\0';
+		if (3 <= len && !strcmp(buf + len - 3, "^{}")) {
+			len -= 3;
+			buf[len] = '\0';
+		}
+		for (ref = buf + len; buf < ref; ref--)
+			if (isspace(ref[-1]))
+				break;
+		if (match) {
+			int reflen = buf + len - ref;
+			if (reflen < matchlen)
+				continue;
+			if (strncmp(ref, match, matchlen))
+				continue;
+		}
+		if (check_ref_format(ref)) {
+			warning("ref '%s' ignored", ref);
+			continue;
+		}
+		if (!string_list_has_string(&existing_refs, ref)) {
+			printf("%s\n", buf);
+		}
+	}
+	return 0;
+}
+
+static int hash_callback(const struct option *opt, const char *arg, int unset)
+{
+	hash_only = 1;
+	/* Use full length SHA1 if no argument */
+	if (!arg)
+		return 0;
+	return parse_opt_abbrev_cb(opt, arg, unset);
+}
+
+static int exclude_existing_callback(const struct option *opt, const char *arg,
+				     int unset)
+{
+	exclude_arg = 1;
+	*(const char **)opt->value = arg;
+	return 0;
+}
+
+static int help_callback(const struct option *opt, const char *arg, int unset)
+{
+	return -1;
+}
+
+static const struct option show_ref_options[] = {
+	OPT_BOOLEAN(0, "tags", &tags_only, "only show tags (can be combined with heads)"),
+	OPT_BOOLEAN(0, "heads", &heads_only, "only show heads (can be combined with tags)"),
+	OPT_BOOLEAN(0, "verify", &verify, "stricter reference checking, "
+		    "requires exact ref path"),
+	{ OPTION_BOOLEAN, 'h', NULL, &show_head, NULL,
+	  "show the HEAD reference",
+	  PARSE_OPT_NOARG | PARSE_OPT_HIDDEN },
+	OPT_BOOLEAN(0, "head", &show_head, "show the HEAD reference"),
+	OPT_BOOLEAN('d', "dereference", &deref_tags,
+		    "dereference tags into object IDs"),
+	{ OPTION_CALLBACK, 's', "hash", &abbrev, "n",
+	  "only show SHA1 hash using <n> digits",
+	  PARSE_OPT_OPTARG, &hash_callback },
+	OPT__ABBREV(&abbrev),
+	OPT__QUIET(&quiet,
+		   "do not print results to stdout (useful with --verify)"),
+	{ OPTION_CALLBACK, 0, "exclude-existing", &exclude_existing_arg,
+	  "pattern", "show refs from stdin that aren't in local repository",
+	  PARSE_OPT_OPTARG | PARSE_OPT_NONEG, exclude_existing_callback },
+	{ OPTION_CALLBACK, 0, "help-all", NULL, NULL, "show usage",
+	  PARSE_OPT_HIDDEN | PARSE_OPT_NOARG, help_callback },
+	OPT_END()
+};
+
+int cmd_show_ref(int argc, const char **argv, const char *prefix)
+{
+	if (argc == 2 && !strcmp(argv[1], "-h"))
+		usage_with_options(show_ref_usage, show_ref_options);
+
+	argc = parse_options(argc, argv, prefix, show_ref_options,
+			     show_ref_usage, PARSE_OPT_NO_INTERNAL_HELP);
+
+	if (exclude_arg)
+		return exclude_existing(exclude_existing_arg);
+
+	pattern = argv;
+	if (!*pattern)
+		pattern = NULL;
+
+	if (verify) {
+		if (!pattern)
+			die("--verify requires a reference");
+		while (*pattern) {
+			unsigned char sha1[20];
+
+			if (!prefixcmp(*pattern, "refs/") &&
+			    resolve_ref(*pattern, sha1, 1, NULL)) {
+				if (!quiet)
+					show_one(*pattern, sha1);
+			}
+			else if (!quiet)
+				die("'%s' - not a valid ref", *pattern);
+			else
+				return 1;
+			pattern++;
+		}
+		return 0;
+	}
+
+	if (show_head)
+		head_ref(show_ref, NULL);
+	for_each_ref(show_ref, NULL);
+	if (!found_match) {
+		if (verify && !quiet)
+			die("No match");
+		return 1;
+	}
+	return 0;
+}