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[PATCH 03/12] Add and use skip_prefix_defval()

From
Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Date
Dec 18, 2013, 14:53 UTC
Message-ID
<1387378437-20646-4-git-send-email-pclouds@gmail.com>
In-Reply-To
<1387378437-20646-1-git-send-email-pclouds@gmail.com>

This is a variant of skip_prefix() that returns a specied pointer instead of NULL if no prefix is found. It's helpful to simplify

  if (starts_with(foo, "bar"))
    foo += 3;
into
  foo = skip_prefix_gently(foo, "bar", foo);
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 builtin/checkout.c    |  6 ++----
 builtin/fast-export.c |  3 +--
 builtin/merge.c       |  4 ++--
 builtin/show-branch.c | 14 +++++---------
 git-compat-util.h     |  9 +++++++--
 git.c                 |  3 +--
 notes.c               |  6 ++----
 wt-status.c           | 12 ++++--------
 8 files changed, 24 insertions(+), 33 deletions(-)
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 5df3837..6531ed4 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1151,10 +1151,8 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		const char *argv0 = argv[0];
 		if (!argc || !strcmp(argv0, "--"))
 			die (_("--track needs a branch name"));
-		if (starts_with(argv0, "refs/"))
-			argv0 += 5;
-		if (starts_with(argv0, "remotes/"))
-			argv0 += 8;
+		argv0 = skip_prefix_defval(argv0, "refs/", argv0);
+		argv0 = skip_prefix_defval(argv0, "remotes/", argv0);
 		argv0 = strchr(argv0, '/');
 		if (!argv0 || !argv0[1])
 			die (_("Missing branch name; try -b"));
diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index b8d8a3a..cd0a302 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -476,8 +476,7 @@ static void handle_tag(const char *name, struct tag *tag)
 		}
 	}
 
-	if (starts_with(name, "refs/tags/"))
-		name += 10;
+	name = skip_prefix_defval(name, "refs/tags/", name);
 	printf("tag %s\nfrom :%d\n%.*s%sdata %d\n%.*s\n",
 	       name, tagged_mark,
 	       (int)(tagger_end - tagger), tagger,
diff --git a/builtin/merge.c b/builtin/merge.c
index 4941a6c..590d907 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -1106,8 +1106,8 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	 * current branch.
 	 */
 	branch = branch_to_free = resolve_refdup("HEAD", head_sha1, 0, &flag);
-	if (branch && starts_with(branch, "refs/heads/"))
-		branch += 11;
+	if (branch)
+		branch = skip_prefix_defval(branch, "refs/heads/", branch);
 	if (!branch || is_null_sha1(head_sha1))
 		head_commit = NULL;
 	else
diff --git a/builtin/show-branch.c b/builtin/show-branch.c
index d9217ce..6078132 100644
--- a/builtin/show-branch.c
+++ b/builtin/show-branch.c
@@ -284,8 +284,7 @@ static void show_one_commit(struct commit *commit, int no_name)
 		pp_commit_easy(CMIT_FMT_ONELINE, commit, &pretty);
 		pretty_str = pretty.buf;
 	}
-	if (starts_with(pretty_str, "[PATCH] "))
-		pretty_str += 8;
+	pretty_str = skip_prefix_defval(pretty_str, "[PATCH] ", pretty_str);
 
 	if (!no_name) {
 		if (name && name->head_name) {
@@ -473,14 +472,13 @@ static void snarf_refs(int head, int remotes)
 	}
 }
 
-static int rev_is_head(char *head, int headlen, char *name,
+static int rev_is_head(const char *head, int headlen, const char *name,
 		       unsigned char *head_sha1, unsigned char *sha1)
 {
 	if ((!head[0]) ||
 	    (head_sha1 && sha1 && hashcmp(head_sha1, sha1)))
 		return 0;
-	if (starts_with(head, "refs/heads/"))
-		head += 11;
+	head = skip_prefix_defval(head, "refs/heads/", head);
 	if (starts_with(name, "refs/heads/"))
 		name += 11;
 	else if (starts_with(name, "heads/"))
@@ -811,10 +809,8 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 					head_sha1, NULL))
 				has_head++;
 		}
-		if (!has_head) {
-			int offset = starts_with(head, "refs/heads/") ? 11 : 0;
-			append_one_rev(head + offset);
-		}
+		if (!has_head)
+			append_one_rev(skip_prefix_defval(head, "refs/heads/", head));
 	}
 
 	if (!ref_name_cnt) {
diff --git a/git-compat-util.h b/git-compat-util.h
index 84f1078..b72a80d 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -354,10 +354,15 @@ extern int prefixcmp(const char *str, const char *prefix);
 extern int ends_with(const char *str, const char *suffix);
 extern int suffixcmp(const char *str, const char *suffix);
 
-static inline const char *skip_prefix(const char *str, const char *prefix)
+static inline const char *skip_prefix_defval(const char *str, const char *prefix, const char *defval)
 {
 	size_t len = strlen(prefix);
-	return strncmp(str, prefix, len) ? NULL : str + len;
+	return strncmp(str, prefix, len) ? defval : str + len;
+}
+
+static inline const char *skip_prefix(const char *str, const char *prefix)
+{
+	return skip_prefix_defval(str, prefix, NULL);
 }
 
 static inline int starts_with(const char *str, const char *prefix)
diff --git a/git.c b/git.c
index 35fda7e..321ae81 100644
--- a/git.c
+++ b/git.c
@@ -579,8 +579,7 @@ int main(int argc, char **av)
 	argc--;
 	handle_options(&argv, &argc, NULL);
 	if (argc > 0) {
-		if (starts_with(argv[0], "--"))
-			argv[0] += 2;
+		argv[0] = skip_prefix_defval(argv[0], "--", argv[0]);
 	} else {
 		/* The user didn't specify a command; give them help */
 		commit_pager_choice();
diff --git a/notes.c b/notes.c
index 5f07c0b..31f513b 100644
--- a/notes.c
+++ b/notes.c
@@ -1243,10 +1243,8 @@ static void format_note(struct notes_tree *t, const unsigned char *object_sha1,
 		if (!ref || !strcmp(ref, GIT_NOTES_DEFAULT_REF)) {
 			strbuf_addstr(sb, "\nNotes:\n");
 		} else {
-			if (starts_with(ref, "refs/"))
-				ref += 5;
-			if (starts_with(ref, "notes/"))
-				ref += 6;
+			ref = skip_prefix_defval(ref, "refs/", ref);
+			ref = skip_prefix_defval(ref, "notes/", ref);
 			strbuf_addf(sb, "\nNotes (%s):\n", ref);
 		}
 	}
diff --git a/wt-status.c b/wt-status.c
index 4e55810..1f65039 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -1179,14 +1179,10 @@ static void wt_status_get_detached_from(struct wt_status_state *state)
 	     /* perhaps sha1 is a tag, try to dereference to a commit */
 	     ((commit = lookup_commit_reference_gently(sha1, 1)) != NULL &&
 	      !hashcmp(cb.nsha1, commit->object.sha1)))) {
-		int ofs;
-		if (starts_with(ref, "refs/tags/"))
-			ofs = strlen("refs/tags/");
-		else if (starts_with(ref, "refs/remotes/"))
-			ofs = strlen("refs/remotes/");
-		else
-			ofs = 0;
-		state->detached_from = xstrdup(ref + ofs);
+		const char *p;
+		if ((p = skip_prefix_defval(ref, "refs/tags/", ref)) == ref)
+			p = skip_prefix_defval(ref, "refs/remotes/", ref);
+		state->detached_from = xstrdup(p);
 	} else
 		state->detached_from =
 			xstrdup(find_unique_abbrev(cb.nsha1, DEFAULT_ABBREV));

-- 
1.8.5.1.208.g019362e
Previous: Jeff KingNext: Kent R. Spillner
Message 14 of 31 in “Hard coded string length cleanup”
  1. 00/12 Hard coded string length cleanupNguyễn Thái Ngọc Duy, Dec 18, 2013
  2. 01/12 Make starts_with() a wrapper of skip_prefix()Nguyễn Thái Ngọc Duy, Dec 18, 2013
  3. Junio C HamanoDec 18, 2013
  4. Junio C HamanoDec 18, 2013
  5. 02/12 Convert starts_with() to skip_prefix() for option parsingNguyễn Thái Ngọc Duy, Dec 18, 2013
  6. Johannes SixtDec 20, 2013
  7. Jeff KingDec 20, 2013
  8. Christian CouderDec 20, 2013
  9. René ScharfeDec 20, 2013
  10. Junio C HamanoDec 20, 2013
  11. Duy NguyenDec 21, 2013
  12. Junio C HamanoDec 26, 2013
  13. Jeff KingDec 28, 2013
  14. 03/12 Add and use skip_prefix_defval()Nguyễn Thái Ngọc Duy, Dec 18, 2013
  15. Kent R. SpillnerDec 18, 2013
  16. Junio C HamanoDec 18, 2013
  17. 04/12 Replace some use of starts_with() with skip_prefix()Nguyễn Thái Ngọc Duy, Dec 18, 2013
  18. 05/12 Convert a lot of starts_with() to skip_prefix()Nguyễn Thái Ngọc Duy, Dec 18, 2013
  19. 06/12 fetch.c: replace some use of starts_with() with skip_prefix()Nguyễn Thái Ngọc Duy, Dec 18, 2013
  20. 07/12 connect.c: replace some use of starts_with() with skip_prefix()Nguyễn Thái Ngọc Duy, Dec 18, 2013
  21. 08/12 refs.c: replace some use of starts_with() with skip_prefix()Nguyễn Thái Ngọc Duy, Dec 18, 2013
  22. 09/12 diff.c: reduce code duplication in --stat-xxx parsingNguyễn Thái Ngọc Duy, Dec 18, 2013
  23. 10/12 environment.c: replace starts_with() in strip_namespace() with skip_prefix()Nguyễn Thái Ngọc Duy, Dec 18, 2013
  24. 11/12 diff.c: convert diff_scoreopt_parse to use skip_prefix()Nguyễn Thái Ngọc Duy, Dec 18, 2013
  25. 12/12 refs.c: use skip_prefix() in prune_ref()Nguyễn Thái Ngọc Duy, Dec 18, 2013
  26. Junio C HamanoDec 18, 2013
  27. René ScharfeDec 19, 2013
  28. Duy NguyenDec 19, 2013
  29. René ScharfeDec 20, 2013
  30. Duy NguyenDec 20, 2013
  31. Junio C HamanoDec 20, 2013

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