/*
 *
 * Copyright (C) 2008, The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <dirent.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>

#include <diskusage/dirsize.h>

int64_t stat_size(struct stat *s)
{
    int64_t blksize = s->st_blksize;
    // count actual blocks used instead of nominal file size
    int64_t size = s->st_blocks * 512;

    if (blksize) {
        /* round up to filesystem block size */
        size = (size + blksize - 1) & (~(blksize - 1));
    }

    return size;
}

int64_t calculate_dir_size(int dfd)
{
    int64_t size = 0;
    struct stat s;
    DIR *d;
    struct dirent *de;

    d = fdopendir(dfd);
    if (d == NULL) {
        close(dfd);
        return 0;
    }

    while ((de = readdir(d))) {
        const char *name = de->d_name;
        if (fstatat(dfd, name, &s, AT_SYMLINK_NOFOLLOW) == 0) {
            size += stat_size(&s);
        }
        if (de->d_type == DT_DIR) {
            int subfd;

            /* always skip "." and ".." */
            if (name[0] == '.') {
                if (name[1] == 0)
                    continue;
                if ((name[1] == '.') && (name[2] == 0))
                    continue;
            }

            subfd = openat(dfd, name, O_RDONLY | O_DIRECTORY);
            if (subfd >= 0) {
                size += calculate_dir_size(subfd);
            }
        }
    }
    closedir(d);
    return size;
}