dir: libify and export helper functions from clone.c

These functions can be useful to other parts of Git. Let's move them to
dir.c, while renaming them to be make their functionality more explicit.

Signed-off-by: Atharva Raykar <raykar.ath@gmail.com>
Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Shourya Shukla <periperidip@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/clone.c

@@ -217,120 +217,6 @@ static char *get_repo_path(const char *repo, int *is_bundle)
 	return canon;
 }
 
-static char *guess_dir_name(const char *repo, int is_bundle, int is_bare)
-{
-	const char *end = repo + strlen(repo), *start, *ptr;
-	size_t len;
-	char *dir;
-
-	/*
-	 * Skip scheme.
-	 */
-	start = strstr(repo, "://");
-	if (start == NULL)
-		start = repo;
-	else
-		start += 3;
-
-	/*
-	 * Skip authentication data. The stripping does happen
-	 * greedily, such that we strip up to the last '@' inside
-	 * the host part.
-	 */
-	for (ptr = start; ptr < end && !is_dir_sep(*ptr); ptr++) {
-		if (*ptr == '@')
-			start = ptr + 1;
-	}
-
-	/*
-	 * Strip trailing spaces, slashes and /.git
-	 */
-	while (start < end && (is_dir_sep(end[-1]) || isspace(end[-1])))
-		end--;
-	if (end - start > 5 && is_dir_sep(end[-5]) &&
-	    !strncmp(end - 4, ".git", 4)) {
-		end -= 5;
-		while (start < end && is_dir_sep(end[-1]))
-			end--;
-	}
-
-	/*
-	 * Strip trailing port number if we've got only a
-	 * hostname (that is, there is no dir separator but a
-	 * colon). This check is required such that we do not
-	 * strip URI's like '/foo/bar:2222.git', which should
-	 * result in a dir '2222' being guessed due to backwards
-	 * compatibility.
-	 */
-	if (memchr(start, '/', end - start) == NULL
-	    && memchr(start, ':', end - start) != NULL) {
-		ptr = end;
-		while (start < ptr && isdigit(ptr[-1]) && ptr[-1] != ':')
-			ptr--;
-		if (start < ptr && ptr[-1] == ':')
-			end = ptr - 1;
-	}
-
-	/*
-	 * Find last component. To remain backwards compatible we
-	 * also regard colons as path separators, such that
-	 * cloning a repository 'foo:bar.git' would result in a
-	 * directory 'bar' being guessed.
-	 */
-	ptr = end;
-	while (start < ptr && !is_dir_sep(ptr[-1]) && ptr[-1] != ':')
-		ptr--;
-	start = ptr;
-
-	/*
-	 * Strip .{bundle,git}.
-	 */
-	len = end - start;
-	strip_suffix_mem(start, &len, is_bundle ? ".bundle" : ".git");
-
-	if (!len || (len == 1 && *start == '/'))
-		die(_("No directory name could be guessed.\n"
-		      "Please specify a directory on the command line"));
-
-	if (is_bare)
-		dir = xstrfmt("%.*s.git", (int)len, start);
-	else
-		dir = xstrndup(start, len);
-	/*
-	 * Replace sequences of 'control' characters and whitespace
-	 * with one ascii space, remove leading and trailing spaces.
-	 */
-	if (*dir) {
-		char *out = dir;
-		int prev_space = 1 /* strip leading whitespace */;
-		for (end = dir; *end; ++end) {
-			char ch = *end;
-			if ((unsigned char)ch < '\x20')
-				ch = '\x20';
-			if (isspace(ch)) {
-				if (prev_space)
-					continue;
-				prev_space = 1;
-			} else
-				prev_space = 0;
-			*out++ = ch;
-		}
-		*out = '\0';
-		if (out > dir && prev_space)
-			out[-1] = '\0';
-	}
-	return dir;
-}
-
-static void strip_trailing_slashes(char *dir)
-{
-	char *end = dir + strlen(dir);
-
-	while (dir < end - 1 && is_dir_sep(end[-1]))
-		end--;
-	*end = '\0';
-}
-
 static int add_one_reference(struct string_list_item *item, void *cb_data)
 {
 	struct strbuf err = STRBUF_INIT;
@@ -1041,8 +927,8 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	if (argc == 2)
 		dir = xstrdup(argv[1]);
 	else
-		dir = guess_dir_name(repo_name, is_bundle, option_bare);
-	strip_trailing_slashes(dir);
+		dir = git_url_basename(repo_name, is_bundle, option_bare);
+	strip_dir_trailing_slashes(dir);
 
 	dest_exists = path_exists(dir);
 	if (dest_exists && !is_empty_dir(dir))

dir.c

@@ -2970,6 +2970,120 @@ int is_empty_dir(const char *path)
 	return ret;
 }
 
+char *git_url_basename(const char *repo, int is_bundle, int is_bare)
+{
+	const char *end = repo + strlen(repo), *start, *ptr;
+	size_t len;
+	char *dir;
+
+	/*
+	 * Skip scheme.
+	 */
+	start = strstr(repo, "://");
+	if (start == NULL)
+		start = repo;
+	else
+		start += 3;
+
+	/*
+	 * Skip authentication data. The stripping does happen
+	 * greedily, such that we strip up to the last '@' inside
+	 * the host part.
+	 */
+	for (ptr = start; ptr < end && !is_dir_sep(*ptr); ptr++) {
+		if (*ptr == '@')
+			start = ptr + 1;
+	}
+
+	/*
+	 * Strip trailing spaces, slashes and /.git
+	 */
+	while (start < end && (is_dir_sep(end[-1]) || isspace(end[-1])))
+		end--;
+	if (end - start > 5 && is_dir_sep(end[-5]) &&
+	    !strncmp(end - 4, ".git", 4)) {
+		end -= 5;
+		while (start < end && is_dir_sep(end[-1]))
+			end--;
+	}
+
+	/*
+	 * Strip trailing port number if we've got only a
+	 * hostname (that is, there is no dir separator but a
+	 * colon). This check is required such that we do not
+	 * strip URI's like '/foo/bar:2222.git', which should
+	 * result in a dir '2222' being guessed due to backwards
+	 * compatibility.
+	 */
+	if (memchr(start, '/', end - start) == NULL
+	    && memchr(start, ':', end - start) != NULL) {
+		ptr = end;
+		while (start < ptr && isdigit(ptr[-1]) && ptr[-1] != ':')
+			ptr--;
+		if (start < ptr && ptr[-1] == ':')
+			end = ptr - 1;
+	}
+
+	/*
+	 * Find last component. To remain backwards compatible we
+	 * also regard colons as path separators, such that
+	 * cloning a repository 'foo:bar.git' would result in a
+	 * directory 'bar' being guessed.
+	 */
+	ptr = end;
+	while (start < ptr && !is_dir_sep(ptr[-1]) && ptr[-1] != ':')
+		ptr--;
+	start = ptr;
+
+	/*
+	 * Strip .{bundle,git}.
+	 */
+	len = end - start;
+	strip_suffix_mem(start, &len, is_bundle ? ".bundle" : ".git");
+
+	if (!len || (len == 1 && *start == '/'))
+		die(_("No directory name could be guessed.\n"
+		      "Please specify a directory on the command line"));
+
+	if (is_bare)
+		dir = xstrfmt("%.*s.git", (int)len, start);
+	else
+		dir = xstrndup(start, len);
+	/*
+	 * Replace sequences of 'control' characters and whitespace
+	 * with one ascii space, remove leading and trailing spaces.
+	 */
+	if (*dir) {
+		char *out = dir;
+		int prev_space = 1 /* strip leading whitespace */;
+		for (end = dir; *end; ++end) {
+			char ch = *end;
+			if ((unsigned char)ch < '\x20')
+				ch = '\x20';
+			if (isspace(ch)) {
+				if (prev_space)
+					continue;
+				prev_space = 1;
+			} else
+				prev_space = 0;
+			*out++ = ch;
+		}
+		*out = '\0';
+		if (out > dir && prev_space)
+			out[-1] = '\0';
+	}
+	return dir;
+}
+
+void strip_dir_trailing_slashes(char *dir)
+{
+	char *end = dir + strlen(dir);
+
+	while (dir < end - 1 && is_dir_sep(end[-1]))
+		end--;
+	*end = '\0';
+}
+
 static int remove_dir_recurse(struct strbuf *path, int flag, int *kept_up)
 {
 	DIR *dir;

dir.h

@@ -453,6 +453,17 @@ static inline int is_dot_or_dotdot(const char *name)
 
 int is_empty_dir(const char *dir);
 
+/*
+ * Retrieve the "humanish" basename of the given Git URL.
+ *
+ * For example:
+ * 	/path/to/repo.git => "repo"
+ * 	host.xz:foo/.git => "foo"
+ * 	http://example.com/user/bar.baz => "bar.baz"
+ */
+char *git_url_basename(const char *repo, int is_bundle, int is_bare);
+void strip_dir_trailing_slashes(char *dir);
+
 void setup_standard_excludes(struct dir_struct *dir);
 
 char *get_sparse_checkout_filename(void);