Make git-branch a builtin

This replaces git-branch.sh with builtin-branch.c

The changes is basically a patch from Kristian Høgsberg, updated
to apply onto current 'next'

Signed-off-by: Lars Hjemli <hjemli@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

5 files changed, 223 insertions, 132 deletions

diff --git a/Makefile b/Makefile
index e826247cca..be8bf392a2 100644
--- a/Makefile
+++ b/Makefile
@@ -156,7 +156,7 @@ BASIC_CFLAGS =
 BASIC_LDFLAGS =
 
 SCRIPT_SH = \
-	git-bisect.sh git-branch.sh git-checkout.sh \
+	git-bisect.sh git-checkout.sh \
 	git-cherry.sh git-clean.sh git-clone.sh git-commit.sh \
 	git-fetch.sh \
 	git-ls-remote.sh \
@@ -267,6 +267,7 @@ BUILTIN_OBJS = \
 	builtin-add.o \
 	builtin-apply.o \
 	builtin-archive.o \
+	builtin-branch.o \
 	builtin-cat-file.o \
 	builtin-checkout-index.o \
 	builtin-check-ref-format.o \
diff --git a/builtin-branch.c b/builtin-branch.c
new file mode 100644
index 0000000000..e028a5390f
--- /dev/null
+++ b/builtin-branch.c
@@ -0,0 +1,219 @@
+/*
+ * Builtin "git branch"
+ *
+ * Copyright (c) 2006 Kristian Høgsberg <krh@redhat.com>
+ * Based on git-branch.sh by Junio C Hamano.
+ */
+
+#include "cache.h"
+#include "refs.h"
+#include "commit.h"
+#include "builtin.h"
+
+static const char builtin_branch_usage[] =
+"git-branch (-d | -D) <branchname> | [-l] [-f] <branchname> [<start-point>] | [-r]";
+
+
+static const char *head;
+static unsigned char head_sha1[20];
+
+static int in_merge_bases(const unsigned char *sha1,
+			  struct commit *rev1,
+			  struct commit *rev2)
+{
+	struct commit_list *bases, *b;
+	int ret = 0;
+
+	bases = get_merge_bases(rev1, rev2, 1);
+	for (b = bases; b; b = b->next) {
+		if (!hashcmp(sha1, b->item->object.sha1)) {
+			ret = 1;
+			break;
+		}
+	}
+
+	free_commit_list(bases);
+	return ret;
+}
+
+static void delete_branches(int argc, const char **argv, int force)
+{
+	struct commit *rev, *head_rev;
+	unsigned char sha1[20];
+	char *name;
+	int i;
+
+	head_rev = lookup_commit_reference(head_sha1);
+	for (i = 0; i < argc; i++) {
+		if (!strcmp(head, argv[i]))
+			die("Cannot delete the branch you are currently on.");
+
+		name = xstrdup(mkpath("refs/heads/%s", argv[i]));
+		if (!resolve_ref(name, sha1, 1, NULL))
+			die("Branch '%s' not found.", argv[i]);
+
+		rev = lookup_commit_reference(sha1);
+		if (!rev || !head_rev)
+			die("Couldn't look up commit objects.");
+
+		/* This checks whether the merge bases of branch and
+		 * HEAD contains branch -- which means that the HEAD
+		 * contains everything in both.
+		 */
+
+		if (!force &&
+		    !in_merge_bases(sha1, rev, head_rev)) {
+			fprintf(stderr,
+				"The branch '%s' is not a strict subset of your current HEAD.\n"
+				"If you are sure you want to delete it, run 'git branch -D %s'.\n",
+				argv[i], argv[i]);
+			exit(1);
+		}
+
+		if (delete_ref(name, sha1))
+			printf("Error deleting branch '%s'\n", argv[i]);
+		else
+			printf("Deleted branch %s.\n", argv[i]);
+
+		free(name);
+	}
+}
+
+static int ref_index, ref_alloc;
+static char **ref_list;
+
+static int append_ref(const char *refname, const unsigned char *sha1, int flags,
+		void *cb_data)
+{
+	if (ref_index >= ref_alloc) {
+		ref_alloc = alloc_nr(ref_alloc);
+		ref_list = xrealloc(ref_list, ref_alloc * sizeof(char *));
+	}
+
+	ref_list[ref_index++] = xstrdup(refname);
+
+	return 0;
+}
+
+static int ref_cmp(const void *r1, const void *r2)
+{
+	return strcmp(*(char **)r1, *(char **)r2);
+}
+
+static void print_ref_list(int remote_only)
+{
+	int i;
+
+	if (remote_only)
+		for_each_remote_ref(append_ref, NULL);
+	else
+		for_each_branch_ref(append_ref, NULL);
+
+	qsort(ref_list, ref_index, sizeof(char *), ref_cmp);
+
+	for (i = 0; i < ref_index; i++) {
+		if (!strcmp(ref_list[i], head))
+			printf("* %s\n", ref_list[i]);
+		else
+			printf("  %s\n", ref_list[i]);
+	}
+}
+
+static void create_branch(const char *name, const char *start,
+			  int force, int reflog)
+{
+	struct ref_lock *lock;
+	struct commit *commit;
+	unsigned char sha1[20];
+	char ref[PATH_MAX], msg[PATH_MAX + 20];
+
+	snprintf(ref, sizeof ref, "refs/heads/%s", name);
+	if (check_ref_format(ref))
+		die("'%s' is not a valid branch name.", name);
+
+	if (resolve_ref(ref, sha1, 1, NULL)) {
+		if (!force)
+			die("A branch named '%s' already exists.", name);
+		else if (!strcmp(head, name))
+			die("Cannot force update the current branch.");
+	}
+
+	if (get_sha1(start, sha1) ||
+	    (commit = lookup_commit_reference(sha1)) == NULL)
+		die("Not a valid branch point: '%s'.", start);
+	hashcpy(sha1, commit->object.sha1);
+
+	lock = lock_any_ref_for_update(ref, NULL);
+	if (!lock)
+		die("Failed to lock ref for update: %s.", strerror(errno));
+
+	if (reflog) {
+		log_all_ref_updates = 1;
+		snprintf(msg, sizeof msg, "branch: Created from %s", start);
+	}
+
+	if (write_ref_sha1(lock, sha1, msg) < 0)
+		die("Failed to write ref: %s.", strerror(errno));
+}
+
+int cmd_branch(int argc, const char **argv, const char *prefix)
+{
+	int delete = 0, force_delete = 0, force_create = 0, remote_only = 0;
+	int reflog = 0;
+	int i;
+
+	git_config(git_default_config);
+
+	for (i = 1; i < argc; i++) {
+		const char *arg = argv[i];
+
+		if (arg[0] != '-')
+			break;
+		if (!strcmp(arg, "--")) {
+			i++;
+			break;
+		}
+		if (!strcmp(arg, "-d")) {
+			delete = 1;
+			continue;
+		}
+		if (!strcmp(arg, "-D")) {
+			delete = 1;
+			force_delete = 1;
+			continue;
+		}
+		if (!strcmp(arg, "-f")) {
+			force_create = 1;
+			continue;
+		}
+		if (!strcmp(arg, "-r")) {
+			remote_only = 1;
+			continue;
+		}
+		if (!strcmp(arg, "-l")) {
+			reflog = 1;
+			continue;
+		}
+		usage(builtin_branch_usage);
+	}
+
+	head = xstrdup(resolve_ref("HEAD", head_sha1, 0, NULL));
+	if (!head)
+		die("Failed to resolve HEAD as a valid ref.");
+	if (strncmp(head, "refs/heads/", 11))
+		die("HEAD not found below refs/heads!");
+	head += 11;
+
+	if (delete)
+		delete_branches(argc - i, argv + i, force_delete);
+	else if (i == argc)
+		print_ref_list(remote_only);
+	else if (i == argc - 1)
+		create_branch(argv[i], head, force_create, reflog);
+	else if (i == argc - 2)
+		create_branch(argv[i], argv[i + 1], force_create, reflog);
+	else
+		usage(builtin_branch_usage);
+
+	return 0;
+}
diff --git a/builtin.h b/builtin.h
index 721b8d8037..db9b369e27 100644
--- a/builtin.h
+++ b/builtin.h
@@ -15,6 +15,7 @@ extern int write_tree(unsigned char *sha1, int missing_ok, const char *prefix);
 extern int cmd_add(int argc, const char **argv, const char *prefix);
 extern int cmd_apply(int argc, const char **argv, const char *prefix);
 extern int cmd_archive(int argc, const char **argv, const char *prefix);
+extern int cmd_branch(int argc, const char **argv, const char *prefix);
 extern int cmd_cat_file(int argc, const char **argv, const char *prefix);
 extern int cmd_checkout_index(int argc, const char **argv, const char *prefix);
 extern int cmd_check_ref_format(int argc, const char **argv, const char *prefix);
diff --git a/git-branch.sh b/git-branch.sh
deleted file mode 100755
index 4379a07210..0000000000
--- a/git-branch.sh
+++ /dev/null
@@ -1,131 +0,0 @@
-#!/bin/sh
-
-USAGE='[-l] [(-d | -D) <branchname>] | [[-f] <branchname> [<start-point>]] | -r'
-LONG_USAGE='If no arguments, show available branches and mark current branch with a star.
-If one argument, create a new branch <branchname> based off of current HEAD.
-If two arguments, create a new branch <branchname> based off of <start-point>.'
-
-SUBDIRECTORY_OK='Yes'
-. git-sh-setup
-
-headref=$(git-symbolic-ref HEAD | sed -e 's|^refs/heads/||')
-
-delete_branch () {
-    option="$1"
-    shift
-    for branch_name
-    do
-	case ",$headref," in
-	",$branch_name,")
-	    die "Cannot delete the branch you are on." ;;
-	,,)
-	    die "What branch are you on anyway?" ;;
-	esac
-	branch=$(git-show-ref --verify --hash -- "refs/heads/$branch_name") &&
-	    branch=$(git-rev-parse --verify "$branch^0") ||
-		die "Seriously, what branch are you talking about?"
-	case "$option" in
-	-D)
-	    ;;
-	*)
-	    mbs=$(git-merge-base -a "$branch" HEAD | tr '\012' ' ')
-	    case " $mbs " in
-	    *' '$branch' '*)
-		# the merge base of branch and HEAD contains branch --
-		# which means that the HEAD contains everything in both.
-		;;
-	    *)
-		echo >&2 "The branch '$branch_name' is not a strict subset of your current HEAD.
-If you are sure you want to delete it, run 'git branch -D $branch_name'."
-		exit 1
-		;;
-	    esac
-	    ;;
-	esac
-	git update-ref -d "refs/heads/$branch_name" "$branch"
-	echo "Deleted branch $branch_name."
-    done
-    exit 0
-}
-
-ls_remote_branches () {
-    git-rev-parse --symbolic --all |
-    sed -ne 's|^refs/\(remotes/\)|\1|p' |
-    sort
-}
-
-force=
-create_log=
-while case "$#,$1" in 0,*) break ;; *,-*) ;; *) break ;; esac
-do
-	case "$1" in
-	-d | -D)
-		delete_branch "$@"
-		exit
-		;;
-	-r)
-		ls_remote_branches
-		exit
-		;;
-	-f)
-		force="$1"
-		;;
-	-l)
-		create_log="yes"
-		;;
-	--)
-		shift
-		break
-		;;
-	-*)
-		usage
-		;;
-	esac
-	shift
-done
-
-case "$#" in
-0)
-	git-rev-parse --symbolic --branches |
-	sort |
-	while read ref
-	do
-		if test "$headref" = "$ref"
-		then
-			pfx='*'
-		else
-			pfx=' '
-		fi
-		echo "$pfx $ref"
-	done
-	exit 0 ;;
-1)
-	head=HEAD ;;
-2)
-	head="$2^0" ;;
-esac
-branchname="$1"
-
-rev=$(git-rev-parse --verify "$head") || exit
-
-git-check-ref-format "heads/$branchname" ||
-	die "we do not like '$branchname' as a branch name."
-
-prev=''
-if git-show-ref --verify --quiet -- "refs/heads/$branchname"
-then
-	if test '' = "$force"
-	then
-		die "$branchname already exists."
-	elif test "$branchname" = "$headref"
-	then
-		die "cannot force-update the current branch."
-	fi
-	prev=`git rev-parse --verify "refs/heads/$branchname"`
-fi
-if test "$create_log" = 'yes'
-then
-	mkdir -p $(dirname "$GIT_DIR/logs/refs/heads/$branchname")
-	touch "$GIT_DIR/logs/refs/heads/$branchname"
-fi
-git update-ref -m "branch: Created from $head" "refs/heads/$branchname" "$rev" "$prev"
diff --git a/git.c b/git.c
index 9108fec808..f197169df2 100644
--- a/git.c
+++ b/git.c
@@ -221,6 +221,7 @@ static void handle_internal_command(int argc, const char **argv, char **envp)
 		{ "add", cmd_add, RUN_SETUP },
 		{ "apply", cmd_apply },
 		{ "archive", cmd_archive },
+		{ "branch", cmd_branch },
 		{ "cat-file", cmd_cat_file, RUN_SETUP },
 		{ "checkout-index", cmd_checkout_index, RUN_SETUP },
 		{ "check-ref-format", cmd_check_ref_format },