ngx_int_t
ngx_walk_tree(ngx_tree_ctx_t *ctx, ngx_str_t *tree)
{
    void       *data, *prev;
    u_char     *p, *name;
    size_t      len;
    ngx_int_t   rc;
    ngx_err_t   err;
    ngx_str_t   file, buf;
    ngx_dir_t   dir;

    ngx_str_null(&buf);

    ngx_log_debug1(NGX_LOG_DEBUG_CORE, ctx->log, 0,
                   "walk tree \"%V\"", tree);

    if (ngx_open_dir(tree, &dir) == NGX_ERROR) {
        ngx_log_error(NGX_LOG_CRIT, ctx->log, ngx_errno,
                      ngx_open_dir_n " \"%s\" failed", tree->data);
        return NGX_ERROR;
    }

    prev = ctx->data;

    if (ctx->alloc) {
        data = ngx_alloc(ctx->alloc, ctx->log);
        if (data == NULL) {
            goto failed;
        }

        if (ctx->init_handler(data, prev) == NGX_ABORT) {
            goto failed;
        }

        ctx->data = data;

    } else {
        data = NULL;
    }

    for ( ;; ) {

        ngx_set_errno(0);

        if (ngx_read_dir(&dir) == NGX_ERROR) {
            err = ngx_errno;

            if (err == NGX_ENOMOREFILES) {
                rc = NGX_OK;

            } else {
                ngx_log_error(NGX_LOG_CRIT, ctx->log, err,
                              ngx_read_dir_n " \"%s\" failed", tree->data);
                rc = NGX_ERROR;
            }

            goto done;
        }

        len = ngx_de_namelen(&dir);
        name = ngx_de_name(&dir);

        ngx_log_debug2(NGX_LOG_DEBUG_CORE, ctx->log, 0,
                      "tree name %uz:\"%s\"", len, name);

        if (len == 1 && name[0] == '.') {
            continue;
        }

        if (len == 2 && name[0] == '.' && name[1] == '.') {
            continue;
        }

        file.len = tree->len + 1 + len;

        if (file.len > buf.len) {

            if (buf.len) {
                ngx_free(buf.data);
            }

            buf.len = tree->len + 1 + len;

            buf.data = ngx_alloc(buf.len + 1, ctx->log);
            if (buf.data == NULL) {
                goto failed;
            }
        }

        p = ngx_cpymem(buf.data, tree->data, tree->len);
        *p++ = '/';
        ngx_memcpy(p, name, len + 1);

        file.data = buf.data;

        ngx_log_debug1(NGX_LOG_DEBUG_CORE, ctx->log, 0,
                       "tree path \"%s\"", file.data);

        if (!dir.valid_info) {
            if (ngx_de_info(file.data, &dir) == NGX_FILE_ERROR) {
                ngx_log_error(NGX_LOG_CRIT, ctx->log, ngx_errno,
                              ngx_de_info_n " \"%s\" failed", file.data);
                continue;
            }
        }

        if (ngx_de_is_file(&dir)) {

            ngx_log_debug1(NGX_LOG_DEBUG_CORE, ctx->log, 0,
                           "tree file \"%s\"", file.data);

            ctx->size = ngx_de_size(&dir);
            ctx->fs_size = ngx_de_fs_size(&dir);
            ctx->access = ngx_de_access(&dir);
            ctx->mtime = ngx_de_mtime(&dir);

            if (ctx->file_handler(ctx, &file) == NGX_ABORT) {
                goto failed;
            }

        } else if (ngx_de_is_dir(&dir)) {

            ngx_log_debug1(NGX_LOG_DEBUG_CORE, ctx->log, 0,
                           "tree enter dir \"%s\"", file.data);

            ctx->access = ngx_de_access(&dir);
            ctx->mtime = ngx_de_mtime(&dir);

            rc = ctx->pre_tree_handler(ctx, &file);

            if (rc == NGX_ABORT) {
                goto failed;
            }

            if (rc == NGX_DECLINED) {
                ngx_log_debug1(NGX_LOG_DEBUG_CORE, ctx->log, 0,
                               "tree skip dir \"%s\"", file.data);
                continue;
            }

            if (ngx_walk_tree(ctx, &file) == NGX_ABORT) {
                goto failed;
            }

            ctx->access = ngx_de_access(&dir);
            ctx->mtime = ngx_de_mtime(&dir);

            if (ctx->post_tree_handler(ctx, &file) == NGX_ABORT) {
                goto failed;
            }

        } else {

            ngx_log_debug1(NGX_LOG_DEBUG_CORE, ctx->log, 0,
                           "tree special \"%s\"", file.data);

            if (ctx->spec_handler(ctx, &file) == NGX_ABORT) {
                goto failed;
            }
        }
    }

failed:

    rc = NGX_ABORT;

done:

    if (buf.len) {
        ngx_free(buf.data);
    }

    if (data) {
        ngx_free(data);
        ctx->data = prev;
    }

    if (ngx_close_dir(&dir) == NGX_ERROR) {
        ngx_log_error(NGX_LOG_CRIT, ctx->log, ngx_errno,
                      ngx_close_dir_n " \"%s\" failed", tree->data);
    }

    return rc;
}