Re: git-branch --print-current

["Arnaud Lacombe" <lacombar@gmail.com>]

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Hi,

On Thu, Jan 1, 2009 at 10:28 PM, Karl Chen <quarl@cs.berkeley.edu> wrote:
>
> How about an option to git-branch that just prints the name of the
> current branch for scripts' sake?  To replace:
>
>    git branch --no-color 2>/dev/null | perl -ne '/^[*] (.*)/ && print $1'
FWIW, I had this in a stalled modification in a tree, it just add the
'-c' (as "current") option to git branch. Patch is mostly for the
record :/

The main trouble I have with pipe stuff is that it forks a process for
something that can be done natively. Previously, I was using awk(1) to
extract the current branch:

$ git branch | awk '/^\*/ {print $2}'

 - Arnaud

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diff --git a/builtin-branch.c b/builtin-branch.c
index 494cbac..2846768 100644
--- a/builtin-branch.c
+++ b/builtin-branch.c
@@ -17,7 +17,7 @@
 #include "revision.h"
 
 static const char * const builtin_branch_usage[] = {
-	"git branch [options] [-r | -a] [--merged | --no-merged]",
+	"git branch [options] [-r | -a | -c] [--merged | --no-merged]",
 	"git branch [options] [-l] [-f] <branchname> [<start-point>]",
 	"git branch [options] [-r] (-d | -D) <branchname>",
 	"git branch [options] (-m | -M) [<oldbranch>] <newbranch>",
@@ -312,9 +312,6 @@ static void print_ref_item(struct ref_item *item, int maxwidth, int verbose,
 	int color;
 	struct commit *commit = item->commit;
 
-	if (!matches_merge_filter(commit))
-		return;
-
 	switch (item->kind) {
 	case REF_LOCAL_BRANCH:
 		color = COLOR_BRANCH_LOCAL;
@@ -373,18 +370,58 @@ static int calc_maxwidth(struct ref_list *refs)
 	return w;
 }
 
-static void print_ref_list(int kinds, int detached, int verbose, int abbrev, struct commit_list *with_commit)
+static inline int is_current(struct ref_item *item, int detached)
+{
+
+	if (detached ||
+	    item->kind != REF_LOCAL_BRANCH ||
+	    strcmp(item->name, head) != 0)
+		return 0;
+
+	return 1;
+}
+
+static void print_ref_list(struct ref_list *ref_list, int kinds, int detached,
+    int verbose, int abbrev, struct commit_list *with_commit)
 {
+	struct commit *head_commit;
 	int i;
+
+	head_commit = lookup_commit_reference_gently(head_sha1, 1);
+
+	detached = (detached && (kinds & REF_LOCAL_BRANCH));
+	if (detached && head_commit && has_commit(head_commit, with_commit)) {
+		struct ref_item item;
+		item.name = xstrdup("(no branch)");
+		item.kind = REF_LOCAL_BRANCH;
+		item.commit = head_commit;
+		if (strlen(item.name) > ref_list->maxwidth)
+			ref_list->maxwidth = strlen(item.name);
+		print_ref_item(&item, ref_list->maxwidth, verbose, abbrev, 1);
+		free(item.name);
+	}
+	for (i = 0; i < ref_list->index; i++) {
+		int current = is_current(&ref_list->list[i], detached);
+		print_ref_item(&ref_list->list[i], ref_list->maxwidth, verbose,
+			       abbrev, current);
+	}
+
+}
+
+static void print_branch(int kinds, int detached, int verbose, int abbrev,
+			 int only_current, struct commit_list *with_commit)
+{
 	struct ref_list ref_list;
-	struct commit *head_commit = lookup_commit_reference_gently(head_sha1, 1);
+	int i;
 
 	memset(&ref_list, 0, sizeof(ref_list));
 	ref_list.kinds = kinds;
 	ref_list.with_commit = with_commit;
 	if (merge_filter != NO_FILTER)
 		init_revisions(&ref_list.revs, NULL);
+
 	for_each_ref(append_ref, &ref_list);
+
 	if (merge_filter != NO_FILTER) {
 		struct commit *filter;
 		filter = lookup_commit_reference_gently(merge_filter_ref, 0);
@@ -399,29 +436,24 @@ static void print_ref_list(int kinds, int detached, int verbose, int abbrev, str
 
 	qsort(ref_list.list, ref_list.index, sizeof(struct ref_item), ref_cmp);
 
-	detached = (detached && (kinds & REF_LOCAL_BRANCH));
-	if (detached && head_commit && has_commit(head_commit, with_commit)) {
-		struct ref_item item;
-		item.name = xstrdup("(no branch)");
-		item.kind = REF_LOCAL_BRANCH;
-		item.commit = head_commit;
-		if (strlen(item.name) > ref_list.maxwidth)
-			ref_list.maxwidth = strlen(item.name);
-		print_ref_item(&item, ref_list.maxwidth, verbose, abbrev, 1);
-		free(item.name);
-	}
+	if (only_current) {
+		for (i = 0; i < ref_list.index; i++) {
+			if (!is_current(&ref_list.list[i], detached))
+				continue;
+			if (!matches_merge_filter(ref_list.list[i].commit))
+				continue;
 
-	for (i = 0; i < ref_list.index; i++) {
-		int current = !detached &&
-			(ref_list.list[i].kind == REF_LOCAL_BRANCH) &&
-			!strcmp(ref_list.list[i].name, head);
-		print_ref_item(&ref_list.list[i], ref_list.maxwidth, verbose,
-			       abbrev, current);
+			printf("%s\n", ref_list.list[i].name);
+		}
+		goto free_it;
 	}
 
+	print_ref_list(&ref_list, kinds, detached, verbose,
+	    abbrev, with_commit);
+
+free_it:
 	free_ref_list(&ref_list);
 }
-
 static void rename_branch(const char *oldname, const char *newname, int force)
 {
 	struct strbuf oldref = STRBUF_INIT, newref = STRBUF_INIT, logmsg = STRBUF_INIT;
@@ -499,7 +531,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 {
 	int delete = 0, rename = 0, force_create = 0;
 	int verbose = 0, abbrev = DEFAULT_ABBREV, detached = 0;
-	int reflog = 0;
+	int only_current = 0, reflog = 0;
 	enum branch_track track;
 	int kinds = REF_LOCAL_BRANCH;
 	struct commit_list *with_commit = NULL;
@@ -524,6 +556,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 			PARSE_OPT_HIDDEN | PARSE_OPT_LASTARG_DEFAULT,
 			opt_parse_with_commit, (intptr_t) "HEAD",
 		},
+		OPT_SET_INT('c', NULL, &only_current, "show only current branch", 1),
 		OPT__ABBREV(&abbrev),
 
 		OPT_GROUP("Specific git-branch actions:"),
@@ -576,9 +609,10 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 
 	if (delete)
 		return delete_branches(argc, argv, delete > 1, kinds);
-	else if (argc == 0)
-		print_ref_list(kinds, detached, verbose, abbrev, with_commit);
-	else if (rename && (argc == 1))
+	else if (argc == 0) {
+		print_branch(kinds, detached, verbose, abbrev, only_current,
+		    with_commit);
+	}else if (rename && (argc == 1))
 		rename_branch(head, argv[0], rename > 1);
 	else if (rename && (argc == 2))
 		rename_branch(argv[0], argv[1], rename > 1);