Merge branch 'jk/skip-prefix'

* jk/skip-prefix:
  http-push: refactor parsing of remote object names
  imap-send: use skip_prefix instead of using magic numbers
  use skip_prefix to avoid repeated calculations
  git: avoid magic number with skip_prefix
  fetch-pack: refactor parsing in get_ack
  fast-import: refactor parsing of spaces
  stat_opt: check extra strlen call
  daemon: use skip_prefix to avoid magic numbers
  fast-import: use skip_prefix for parsing input
  use skip_prefix to avoid repeating strings
  use skip_prefix to avoid magic numbers
  transport-helper: avoid reading past end-of-string
  fast-import: fix read of uninitialized argv memory
  apply: use skip_prefix instead of raw addition
  refactor skip_prefix to return a boolean
  avoid using skip_prefix as a boolean
  daemon: mark some strings as const
  parse_diff_color_slot: drop ofs parameter

9 files changed, 32 insertions, 32 deletions

diff --git a/builtin/apply.c b/builtin/apply.c
index 9c5724eacc..bc924ab2d0 100644
--- a/builtin/apply.c
+++ b/builtin/apply.c
@@ -3847,9 +3847,10 @@ static void add_index_file(const char *path, unsigned mode, void *buf, unsigned
 	ce->ce_flags = create_ce_flags(0);
 	ce->ce_namelen = namelen;
 	if (S_ISGITLINK(mode)) {
-		const char *s = buf;
+		const char *s;
 
-		if (get_sha1_hex(s + strlen("Subproject commit "), ce->sha1))
+		if (!skip_prefix(buf, "Subproject commit ", &s) ||
+		    get_sha1_hex(s, ce->sha1))
 			die(_("corrupt patch for submodule %s"), path);
 	} else {
 		if (!cached) {
diff --git a/builtin/branch.c b/builtin/branch.c
index 652b1d2d14..0591b22a48 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -294,13 +294,13 @@ static char *resolve_symref(const char *src, const char *prefix)
 {
 	unsigned char sha1[20];
 	int flag;
-	const char *dst, *cp;
+	const char *dst;
 
 	dst = resolve_ref_unsafe(src, sha1, 0, &flag);
 	if (!(dst && (flag & REF_ISSYMREF)))
 		return NULL;
-	if (prefix && (cp = skip_prefix(dst, prefix)))
-		dst = cp;
+	if (prefix)
+		skip_prefix(dst, prefix, &dst);
 	return xstrdup(dst);
 }
 
diff --git a/builtin/checkout.c b/builtin/checkout.c
index f1dc56e55f..463cfeea50 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -776,8 +776,8 @@ static int switch_branches(const struct checkout_opts *opts,
 	if (!(flag & REF_ISSYMREF))
 		old.path = NULL;
 
-	if (old.path && starts_with(old.path, "refs/heads/"))
-		old.name = old.path + strlen("refs/heads/");
+	if (old.path)
+		skip_prefix(old.path, "refs/heads/", &old.name);
 
 	if (!new->name) {
 		new->name = "HEAD";
diff --git a/builtin/clone.c b/builtin/clone.c
index b12989d1ca..a5b2d9db36 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -584,11 +584,11 @@ static void update_remote_refs(const struct ref *refs,
 static void update_head(const struct ref *our, const struct ref *remote,
 			const char *msg)
 {
-	if (our && starts_with(our->name, "refs/heads/")) {
+	const char *head;
+	if (our && skip_prefix(our->name, "refs/heads/", &head)) {
 		/* Local default branch link */
 		create_symref("HEAD", our->name, NULL);
 		if (!option_bare) {
-			const char *head = skip_prefix(our->name, "refs/heads/");
 			update_ref(msg, "HEAD", our->old_sha1, NULL, 0,
 				   UPDATE_REFS_DIE_ON_ERR);
 			install_branch_config(0, head, option_origin, our->name);
@@ -703,9 +703,12 @@ static void write_refspec_config(const char* src_ref_prefix,
 					strbuf_addf(&value, "+%s:%s%s", our_head_points_at->name,
 						branch_top->buf, option_branch);
 			} else if (remote_head_points_at) {
+				const char *head = remote_head_points_at->name;
+				if (!skip_prefix(head, "refs/heads/", &head))
+					die("BUG: remote HEAD points at non-head?");
+
 				strbuf_addf(&value, "+%s:%s%s", remote_head_points_at->name,
-						branch_top->buf,
-						skip_prefix(remote_head_points_at->name, "refs/heads/"));
+						branch_top->buf, head);
 			}
 			/*
 			 * otherwise, the next "git fetch" will
diff --git a/builtin/commit.c b/builtin/commit.c
index 84cec9a715..461c3b1cad 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1020,7 +1020,7 @@ static int message_is_empty(struct strbuf *sb)
 static int template_untouched(struct strbuf *sb)
 {
 	struct strbuf tmpl = STRBUF_INIT;
-	char *start;
+	const char *start;
 
 	if (cleanup_mode == CLEANUP_NONE && sb->len)
 		return 0;
@@ -1029,8 +1029,7 @@ static int template_untouched(struct strbuf *sb)
 		return 0;
 
 	stripspace(&tmpl, cleanup_mode == CLEANUP_ALL);
-	start = (char *)skip_prefix(sb->buf, tmpl.buf);
-	if (!start)
+	if (!skip_prefix(sb->buf, tmpl.buf, &start))
 		start = sb->buf;
 	strbuf_release(&tmpl);
 	return rest_is_empty(sb, start - sb->buf);
diff --git a/builtin/fmt-merge-msg.c b/builtin/fmt-merge-msg.c
index ef8b254ef2..971e802c6f 100644
--- a/builtin/fmt-merge-msg.c
+++ b/builtin/fmt-merge-msg.c
@@ -100,7 +100,8 @@ static int handle_line(char *line, struct merge_parents *merge_parents)
 {
 	int i, len = strlen(line);
 	struct origin_data *origin_data;
-	char *src, *origin;
+	char *src;
+	const char *origin;
 	struct src_data *src_data;
 	struct string_list_item *item;
 	int pulling_head = 0;
@@ -164,8 +165,7 @@ static int handle_line(char *line, struct merge_parents *merge_parents)
 		origin = line;
 		string_list_append(&src_data->tag, origin + 4);
 		src_data->head_status |= 2;
-	} else if (starts_with(line, "remote-tracking branch ")) {
-		origin = line + strlen("remote-tracking branch ");
+	} else if (skip_prefix(line, "remote-tracking branch ", &origin)) {
 		string_list_append(&src_data->r_branch, origin);
 		src_data->head_status |= 2;
 	} else {
@@ -300,8 +300,8 @@ static void credit_people(struct strbuf *out,
 	if (!them->nr ||
 	    (them->nr == 1 &&
 	     me &&
-	     (me = skip_prefix(me, them->items->string)) != NULL &&
-	     skip_prefix(me, " <")))
+	     skip_prefix(me, them->items->string, &me) &&
+	     starts_with(me, " <")))
 		return;
 	strbuf_addf(out, "\n%c %s ", comment_line_char, label);
 	add_people_count(out, them);
diff --git a/builtin/log.c b/builtin/log.c
index 92063dfc48..27c1b65db4 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -871,7 +871,7 @@ static char *find_branch_name(struct rev_info *rev)
 	int i, positive = -1;
 	unsigned char branch_sha1[20];
 	const unsigned char *tip_sha1;
-	const char *ref;
+	const char *ref, *v;
 	char *full_ref, *branch = NULL;
 
 	for (i = 0; i < rev->cmdline.nr; i++) {
@@ -887,9 +887,9 @@ static char *find_branch_name(struct rev_info *rev)
 	ref = rev->cmdline.rev[positive].name;
 	tip_sha1 = rev->cmdline.rev[positive].item->sha1;
 	if (dwim_ref(ref, strlen(ref), branch_sha1, &full_ref) &&
-	    starts_with(full_ref, "refs/heads/") &&
+	    skip_prefix(full_ref, "refs/heads/", &v) &&
 	    !hashcmp(tip_sha1, branch_sha1))
-		branch = xstrdup(full_ref + strlen("refs/heads/"));
+		branch = xstrdup(v);
 	free(full_ref);
 	return branch;
 }
@@ -1396,10 +1396,10 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 
 		if (check_head) {
 			unsigned char sha1[20];
-			const char *ref;
+			const char *ref, *v;
 			ref = resolve_ref_unsafe("HEAD", sha1, 1, NULL);
-			if (ref && starts_with(ref, "refs/heads/"))
-				branch_name = xstrdup(ref + strlen("refs/heads/"));
+			if (ref && skip_prefix(ref, "refs/heads/", &v))
+				branch_name = xstrdup(v);
 			else
 				branch_name = xstrdup(""); /* no branch */
 		}
diff --git a/builtin/push.c b/builtin/push.c
index f8dfea41e1..f50e3d5e77 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -127,11 +127,10 @@ static NORETURN int die_push_simple(struct branch *branch, struct remote *remote
 	 * them the big ugly fully qualified ref.
 	 */
 	const char *advice_maybe = "";
-	const char *short_upstream =
-		skip_prefix(branch->merge[0]->src, "refs/heads/");
+	const char *short_upstream = branch->merge[0]->src;
+
+	skip_prefix(short_upstream, "refs/heads/", &short_upstream);
 
-	if (!short_upstream)
-		short_upstream = branch->merge[0]->src;
 	/*
 	 * Don't show advice for people who explicitly set
 	 * push.default.
diff --git a/builtin/remote.c b/builtin/remote.c
index c9102e8fe9..a8efe3da4d 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -250,9 +250,7 @@ static struct string_list branch_list;
 
 static const char *abbrev_ref(const char *name, const char *prefix)
 {
-	const char *abbrev = skip_prefix(name, prefix);
-	if (abbrev)
-		return abbrev;
+	skip_prefix(name, prefix, &name);
 	return name;
 }
 #define abbrev_branch(name) abbrev_ref((name), "refs/heads/")