Merge branch 'nd/maint-setup'

* nd/maint-setup:
  Kill off get_relative_cwd()
  setup: return correct prefix if worktree is '/'

Conflicts:
	dir.c
	setup.c

dir.c

@@ -1105,57 +1105,45 @@ int file_exists(const char *f)
 }
 
 /*
- * get_relative_cwd() gets the prefix of the current working directory
- * relative to 'dir'.  If we are not inside 'dir', it returns NULL.
- *
- * As a convenience, it also returns NULL if 'dir' is already NULL.  The
- * reason for this behaviour is that it is natural for functions returning
- * directory names to return NULL to say "this directory does not exist"
- * or "this directory is invalid".  These cases are usually handled the
- * same as if the cwd is not inside 'dir' at all, so get_relative_cwd()
- * returns NULL for both of them.
- *
- * Most notably, get_relative_cwd(buffer, size, get_git_work_tree())
- * unifies the handling of "outside work tree" with "no work tree at all".
+ * Given two normalized paths (a trailing slash is ok), if subdir is
+ * outside dir, return -1.  Otherwise return the offset in subdir that
+ * can be used as relative path to dir.
  */
-char *get_relative_cwd(char *buffer, int size, const char *dir)
+int dir_inside_of(const char *subdir, const char *dir)
 {
-	char *cwd = buffer;
+	int offset = 0;
 
-	if (!dir)
-		return NULL;
-	if (!getcwd(buffer, size))
-		die_errno("can't find the current directory");
+	assert(dir && subdir && *dir && *subdir);
 
-	if (!is_absolute_path(dir))
-		dir = real_path(dir);
-
-	while (*dir && *dir == *cwd) {
+	while (*dir && *subdir && *dir == *subdir) {
 		dir++;
-		cwd++;
-	}
-	if (*dir)
-		return NULL;
-	switch (*cwd) {
-	case '\0':
-		return cwd;
-	case '/':
-		return cwd + 1;
-	default:
-		/*
-		 * dir can end with a path separator when it's root
-		 * directory. Return proper prefix in that case.
-		 */
-		if (dir[-1] == '/')
-			return cwd;
-		return NULL;
+		subdir++;
+		offset++;
 	}
+
+	/* hel[p]/me vs hel[l]/yeah */
+	if (*dir && *subdir)
+		return -1;
+
+	if (!*subdir)
+		return !*dir ? offset : -1; /* same dir */
+
+	/* foo/[b]ar vs foo/[] */
+	if (is_dir_sep(dir[-1]))
+		return is_dir_sep(subdir[-1]) ? offset : -1;
+
+	/* foo[/]bar vs foo[] */
+	return is_dir_sep(*subdir) ? offset + 1 : -1;
 }
 
 int is_inside_dir(const char *dir)
 {
-	char buffer[PATH_MAX];
-	return get_relative_cwd(buffer, sizeof(buffer), dir) != NULL;
+	char cwd[PATH_MAX];
+	if (!dir)
+		return 0;
+	if (!getcwd(cwd, sizeof(cwd)))
+		die_errno("can't find the current directory");
+	return dir_inside_of(cwd, dir) >= 0;
 }
 
 int is_empty_dir(const char *path)

dir.h

@@ -85,8 +85,8 @@ extern void add_exclude(const char *string, const char *base,
 extern void free_excludes(struct exclude_list *el);
 extern int file_exists(const char *);
 
-extern char *get_relative_cwd(char *buffer, int size, const char *dir);
 extern int is_inside_dir(const char *dir);
+extern int dir_inside_of(const char *subdir, const char *dir);
 
 static inline int is_dot_or_dotdot(const char *name)
 {

setup.c

@@ -325,6 +325,7 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,
 	const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 	const char *worktree;
 	char *gitfile;
+	int offset;
 
 	if (PATH_MAX - 40 < strlen(gitdirenv))
 		die("'$%s' too big", GIT_DIR_ENVIRONMENT);
@@ -390,15 +391,15 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,
 		return NULL;
 	}
 
-	if (!prefixcmp(cwd, worktree) &&
-	    cwd[strlen(worktree)] == '/') { /* cwd inside worktree */
+	offset = dir_inside_of(cwd, worktree);
+	if (offset >= 0) {	/* cwd inside worktree? */
 		set_git_dir(real_path(gitdirenv));
 		if (chdir(worktree))
 			die_errno("Could not chdir to '%s'", worktree);
 		cwd[len++] = '/';
 		cwd[len] = '\0';
 		free(gitfile);
-		return cwd + strlen(worktree) + 1;
+		return cwd + offset;
 	}
 
 	/* cwd outside worktree */