Merge branch 'lt/ref2' into next

* lt/ref2:
  Teach "git checkout" to use git-show-ref
  Add "git show-ref" builtin command

Makefile

@@ -310,7 +310,8 @@ BUILTIN_OBJS = \
 	builtin-upload-tar.o \
 	builtin-verify-pack.o \
 	builtin-write-tree.o \
-	builtin-zip-tree.o
+	builtin-zip-tree.o \
+	builtin-show-ref.o
 
 GITLIBS = $(LIB_FILE) $(XDIFF_LIB)
 EXTLIBS = -lz

builtin-show-ref.c

@@ -0,0 +1,112 @@
+#include "cache.h"
+#include "refs.h"
+#include "object.h"
+#include "tag.h"
+
+static const char show_ref_usage[] = "git show-ref [-q|--quiet] [--verify] [-h|--head] [-d|--deref] [--tags] [--heads] [--] [pattern*]";
+
+static int deref_tags = 0, show_head = 0, tags_only = 0, heads_only = 0, found_match = 0, verify = 0, quiet = 0;
+static const char **pattern;
+
+static int show_ref(const char *refname, const unsigned char *sha1)
+{
+	struct object *obj;
+
+	if (tags_only || heads_only) {
+		int match;
+
+		match = heads_only && !strncmp(refname, "refs/heads/", 11);
+		match |= tags_only && !strncmp(refname, "refs/tags/", 10);
+		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++;
+	obj = parse_object(sha1);
+	if (!obj) {
+		if (quiet)
+			return 0;
+		die("git-show-ref: bad ref %s (%s)", refname, sha1_to_hex(sha1));
+	}
+	if (quiet)
+		return 0;
+	printf("%s %s\n", sha1_to_hex(sha1), refname);
+	if (deref_tags && obj->type == OBJ_TAG) {
+		obj = deref_tag(obj, refname, 0);
+		printf("%s %s^{}\n", sha1_to_hex(obj->sha1), refname);
+	}
+	return 0;
+}
+
+int cmd_show_ref(int argc, const char **argv, const char *prefix)
+{
+	int i;
+
+	for (i = 1; i < argc; i++) {
+		const char *arg = argv[i];
+		if (*arg != '-') {
+			pattern = argv + i;
+			break;
+		}
+		if (!strcmp(arg, "--")) {
+			pattern = argv + i + 1;
+			if (!*pattern)
+				pattern = NULL;
+			break;
+		}
+		if (!strcmp(arg, "-q") || !strcmp(arg, "--quiet")) {
+			quiet = 1;
+			continue;
+		}
+		if (!strcmp(arg, "-h") || !strcmp(arg, "--head")) {
+			show_head = 1;
+			continue;
+		}
+		if (!strcmp(arg, "-d") || !strcmp(arg, "--dereference")) {
+			deref_tags = 1;
+			continue;
+		}
+		if (!strcmp(arg, "--verify")) {
+			verify = 1;
+			continue;
+		}
+		if (!strcmp(arg, "--tags")) {
+			tags_only = 1;
+			continue;
+		}
+		if (!strcmp(arg, "--heads")) {
+			heads_only = 1;
+			continue;
+		}
+		usage(show_ref_usage);
+	}
+	if (show_head)
+		head_ref(show_ref);
+	for_each_ref(show_ref);
+	if (!found_match) {
+		if (verify && !quiet)
+			die("No match");
+		return 1;
+	}
+	return 0;
+}

builtin.h

@@ -63,5 +63,6 @@ extern int cmd_version(int argc, const char **argv, const char *prefix);
 extern int cmd_whatchanged(int argc, const char **argv, const char *prefix);
 extern int cmd_write_tree(int argc, const char **argv, const char *prefix);
 extern int cmd_verify_pack(int argc, const char **argv, const char *prefix);
+extern int cmd_show_ref(int argc, const char **argv, const char *prefix);
 
 #endif

git-checkout.sh

@@ -22,7 +22,7 @@ while [ "$#" != "0" ]; do
 		shift
 		[ -z "$newbranch" ] &&
 			die "git checkout: -b needs a branch name"
-		[ -e "$GIT_DIR/refs/heads/$newbranch" ] &&
+		git-show-ref --verify --quiet -- "refs/heads/$newbranch" &&
 			die "git checkout: branch $newbranch already exists"
 		git-check-ref-format "heads/$newbranch" ||
 			die "git checkout: we do not like '$newbranch' as a branch name."
@@ -51,7 +51,8 @@ while [ "$#" != "0" ]; do
 			fi
 			new="$rev"
 			new_name="$arg^0"
-			if [ -f "$GIT_DIR/refs/heads/$arg" ]; then
+			if git-show-ref --verify --quiet -- "refs/heads/$arg"
+			then
 				branch="$arg"
 			fi
 		elif rev=$(git-rev-parse --verify "$arg^{tree}" 2>/dev/null)

git.c

@@ -269,6 +269,7 @@ static void handle_internal_command(int argc, const char **argv, char **envp)
 		{ "whatchanged", cmd_whatchanged, RUN_SETUP | USE_PAGER },
 		{ "write-tree", cmd_write_tree, RUN_SETUP },
 		{ "verify-pack", cmd_verify_pack },
+		{ "show-ref", cmd_show_ref, RUN_SETUP },
 	};
 	int i;