merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/dir-iterator.h

@@ -0,0 +1,127 @@
+#ifndef DIR_ITERATOR_H
+#define DIR_ITERATOR_H
+
+#include "strbuf.h"
+
+/*
+ * Iterate over a directory tree.
+ *
+ * Iterate over a directory tree, recursively, including paths of all
+ * types and hidden paths. Skip "." and ".." entries and don't follow
+ * symlinks except for the original path. Note that the original path
+ * is not included in the iteration.
+ *
+ * Every time dir_iterator_advance() is called, update the members of
+ * the dir_iterator structure to reflect the next path in the
+ * iteration. The order that paths are iterated over within a
+ * directory is undefined, directory paths are always given before
+ * their contents.
+ *
+ * A typical iteration looks like this:
+ *
+ *     int ok;
+ *     unsigned int flags = DIR_ITERATOR_PEDANTIC;
+ *     struct dir_iterator *iter = dir_iterator_begin(path, flags);
+ *
+ *     if (!iter)
+ *             goto error_handler;
+ *
+ *     while ((ok = dir_iterator_advance(iter)) == ITER_OK) {
+ *             if (want_to_stop_iteration()) {
+ *                     ok = dir_iterator_abort(iter);
+ *                     break;
+ *             }
+ *
+ *             // Access information about the current path:
+ *             if (S_ISDIR(iter->st.st_mode))
+ *                     printf("%s is a directory\n", iter->relative_path);
+ *     }
+ *
+ *     if (ok != ITER_DONE)
+ *             handle_error();
+ *
+ * Callers are allowed to modify iter->path while they are working,
+ * but they must restore it to its original contents before calling
+ * dir_iterator_advance() again.
+ */
+
+/*
+ * Flags for dir_iterator_begin:
+ *
+ * - DIR_ITERATOR_PEDANTIC: override dir-iterator's default behavior
+ *   in case of an error at dir_iterator_advance(), which is to keep
+ *   looking for a next valid entry. With this flag, resources are freed
+ *   and ITER_ERROR is returned immediately. In both cases, a meaningful
+ *   warning is emitted. Note: ENOENT errors are always ignored so that
+ *   the API users may remove files during iteration.
+ *
+ * - DIR_ITERATOR_FOLLOW_SYMLINKS: make dir-iterator follow symlinks.
+ *   i.e., linked directories' contents will be iterated over and
+ *   iter->base.st will contain information on the referred files,
+ *   not the symlinks themselves, which is the default behavior. Broken
+ *   symlinks are ignored.
+ *
+ * Warning: circular symlinks are also followed when
+ * DIR_ITERATOR_FOLLOW_SYMLINKS is set. The iteration may end up with
+ * an ELOOP if they happen and DIR_ITERATOR_PEDANTIC is set.
+ */
+#define DIR_ITERATOR_PEDANTIC (1 << 0)
+#define DIR_ITERATOR_FOLLOW_SYMLINKS (1 << 1)
+
+struct dir_iterator {
+	/* The current path: */
+	struct strbuf path;
+
+	/*
+	 * The current path relative to the starting path. This part
+	 * of the path always uses "/" characters to separate path
+	 * components:
+	 */
+	const char *relative_path;
+
+	/* The current basename: */
+	const char *basename;
+
+	/*
+	 * The result of calling lstat() on path; or stat(), if the
+	 * DIR_ITERATOR_FOLLOW_SYMLINKS flag was set at
+	 * dir_iterator's initialization.
+	 */
+	struct stat st;
+};
+
+/*
+ * Start a directory iteration over path with the combination of
+ * options specified by flags. On success, return a dir_iterator
+ * that holds the internal state of the iteration. In case of
+ * failure, return NULL and set errno accordingly.
+ *
+ * The iteration includes all paths under path, not including path
+ * itself and not including "." or ".." entries.
+ *
+ * Parameters are:
+ *  - path is the starting directory. An internal copy will be made.
+ *  - flags is a combination of the possible flags to initialize a
+ *    dir-iterator or 0 for default behavior.
+ */
+struct dir_iterator *dir_iterator_begin(const char *path, unsigned int flags);
+
+/*
+ * Advance the iterator to the first or next item and return ITER_OK.
+ * If the iteration is exhausted, free the dir_iterator and any
+ * resources associated with it and return ITER_DONE.
+ *
+ * It is a bug to use iterator or call this function again after it
+ * has returned ITER_DONE or ITER_ERROR (which may be returned iff
+ * the DIR_ITERATOR_PEDANTIC flag was set).
+ */
+int dir_iterator_advance(struct dir_iterator *iterator);
+
+/*
+ * End the iteration before it has been exhausted. Free the
+ * dir_iterator and any associated resources and return ITER_DONE. On
+ * error, free the dir_iterator and return ITER_ERROR.
+ */
+int dir_iterator_abort(struct dir_iterator *iterator);
+
+#endif