+ return (char *)cleanup_path(buf);
+}
+
+static int dir_prefix(const char *buf, const char *dir)
+{
+ int len = strlen(dir);
+ return !strncmp(buf, dir, len) &&
+ (is_dir_sep(buf[len]) || buf[len] == '\0');
+}
+
+/* $buf =~ m|$dir/+$file| but without regex */
+static int is_dir_file(const char *buf, const char *dir, const char *file)
+{
+ int len = strlen(dir);
+ if (strncmp(buf, dir, len) || !is_dir_sep(buf[len]))
+ return 0;
+ while (is_dir_sep(buf[len]))
+ len++;
+ return !strcmp(buf + len, file);
+}
+
+static void replace_dir(struct strbuf *buf, int len, const char *newdir)
+{
+ int newlen = strlen(newdir);
+ int need_sep = (buf->buf[len] && !is_dir_sep(buf->buf[len])) &&
+ !is_dir_sep(newdir[newlen - 1]);
+ if (need_sep)
+ len--; /* keep one char, to be replaced with '/' */
+ strbuf_splice(buf, 0, len, newdir, newlen);
+ if (need_sep)
+ buf->buf[newlen] = '/';
+}
+
+struct common_dir {
+ /* Not considered garbage for report_linked_checkout_garbage */
+ unsigned ignore_garbage:1;
+ unsigned is_dir:1;
+ /* Belongs to the common dir, though it may contain paths that don't */
+ unsigned is_common:1;
+ const char *path;
+};
+
+static struct common_dir common_list[] = {
+ { 0, 1, 1, "branches" },
+ { 0, 1, 1, "common" },
+ { 0, 1, 1, "hooks" },
+ { 0, 1, 1, "info" },
+ { 0, 0, 0, "info/sparse-checkout" },
+ { 1, 1, 1, "logs" },
+ { 1, 0, 0, "logs/HEAD" },
+ { 0, 1, 0, "logs/refs/bisect" },
+ { 0, 1, 0, "logs/refs/rewritten" },
+ { 0, 1, 0, "logs/refs/worktree" },
+ { 0, 1, 1, "lost-found" },
+ { 0, 1, 1, "objects" },
+ { 0, 1, 1, "refs" },
+ { 0, 1, 0, "refs/bisect" },
+ { 0, 1, 0, "refs/rewritten" },
+ { 0, 1, 0, "refs/worktree" },
+ { 0, 1, 1, "remotes" },
+ { 0, 1, 1, "worktrees" },
+ { 0, 1, 1, "rr-cache" },
+ { 0, 1, 1, "svn" },
+ { 0, 0, 1, "config" },
+ { 1, 0, 1, "gc.pid" },
+ { 0, 0, 1, "packed-refs" },
+ { 0, 0, 1, "shallow" },
+ { 0, 0, 0, NULL }
+};
+
+/*
+ * A compressed trie. A trie node consists of zero or more characters that
+ * are common to all elements with this prefix, optionally followed by some
+ * children. If value is not NULL, the trie node is a terminal node.
+ *
+ * For example, consider the following set of strings:
+ * abc
+ * def
+ * definite
+ * definition
+ *
+ * The trie would look like:
+ * root: len = 0, children a and d non-NULL, value = NULL.
+ * a: len = 2, contents = bc, value = (data for "abc")
+ * d: len = 2, contents = ef, children i non-NULL, value = (data for "def")
+ * i: len = 3, contents = nit, children e and i non-NULL, value = NULL
+ * e: len = 0, children all NULL, value = (data for "definite")
+ * i: len = 2, contents = on, children all NULL,
+ * value = (data for "definition")
+ */
+struct trie {
+ struct trie *children[256];
+ int len;
+ char *contents;
+ void *value;
+};
+
+static struct trie *make_trie_node(const char *key, void *value)
+{
+ struct trie *new_node = xcalloc(1, sizeof(*new_node));
+ new_node->len = strlen(key);
+ if (new_node->len) {
+ new_node->contents = xmalloc(new_node->len);
+ memcpy(new_node->contents, key, new_node->len);
+ }
+ new_node->value = value;
+ return new_node;
+}
+
+/*
+ * Add a key/value pair to a trie. The key is assumed to be \0-terminated.
+ * If there was an existing value for this key, return it.
+ */
+static void *add_to_trie(struct trie *root, const char *key, void *value)
+{
+ struct trie *child;
+ void *old;
+ int i;
+
+ if (!*key) {
+ /* we have reached the end of the key */
+ old = root->value;
+ root->value = value;
+ return old;
+ }
+
+ for (i = 0; i < root->len; i++) {
+ if (root->contents[i] == key[i])
+ continue;
+
+ /*
+ * Split this node: child will contain this node's
+ * existing children.
+ */
+ child = xmalloc(sizeof(*child));
+ memcpy(child->children, root->children, sizeof(root->children));
+
+ child->len = root->len - i - 1;
+ if (child->len) {
+ child->contents = xstrndup(root->contents + i + 1,
+ child->len);
+ }
+ child->value = root->value;
+ root->value = NULL;
+ root->len = i;
+
+ memset(root->children, 0, sizeof(root->children));
+ root->children[(unsigned char)root->contents[i]] = child;
+
+ /* This is the newly-added child. */
+ root->children[(unsigned char)key[i]] =
+ make_trie_node(key + i + 1, value);
+ return NULL;
+ }
+
+ /* We have matched the entire compressed section */
+ if (key[i]) {
+ child = root->children[(unsigned char)key[root->len]];
+ if (child) {
+ return add_to_trie(child, key + root->len + 1, value);
+ } else {
+ child = make_trie_node(key + root->len + 1, value);
+ root->children[(unsigned char)key[root->len]] = child;
+ return NULL;
+ }
+ }
+
+ old = root->value;
+ root->value = value;
+ return old;