/*
Copyright (c) 2003-2006 by Juliusz Chroboczek

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

/* This file implements just enough of the fts family of functions
   to make Polipo happy. */

#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
#include <errno.h>
#include <string.h>

#include "fts_compat.h"

static char *
getcwd_a()
{
    char buf[256];
    char *ret;
    ret = getcwd(buf, 256);
    if(ret == NULL)
        return NULL;
    return strdup(buf);
}

static char *
mkfilename(const char *path, char *filename)
{
    int n = strlen(path);
    char *buf = malloc(n + 1 + strlen(filename) + 1);
    if(buf == NULL)
        return NULL;
    memcpy(buf, path, n);
    if(buf[n - 1] != '/')
        buf[n++] = '/';
    strcpy(buf + n, filename);
    return buf;
}

static int
split(const char *path, int *slash_return, int *dlen, int *blen)
{
    int len; int slash;
    len = strlen(path);
    while(len > 0 && path[len - 1] == '/')
        len--;
    if(len == 0)
        return -1;
    slash = len - 1;
    while(slash >= 0 && path[slash] != '/')
        slash--;

    if(slash_return) *slash_return = slash;
    if(dlen) *dlen = slash + 1;
    if(blen) *blen = len - slash - 1;
    return 1;
}

static char *
basename_a(const char *path)
{
    int blen, slash;
    char *b;
    int rc;

    rc = split(path, &slash, NULL, &blen);
    if(rc < 0 || blen == 0)
        return NULL;

    b = malloc(blen + 1);
    if(b == NULL)
        return NULL;
    memcpy(b, path + slash + 1, blen);
    b[blen] = '\0';
    return b;
}

static char *
dirname_a(const char *path)
{
    int dlen;
    int rc;
    char *d;

    rc = split(path, NULL, &dlen, NULL);
    if(rc < 0)
        return NULL;

    d = malloc(dlen + 1);
    if(d == NULL)
        return NULL;
    memcpy(d, path, dlen);
    d[dlen] = '\0';
    return d;
}

#if defined(__svr4__) || defined(SVR4)
static int
dirfd(DIR *dir)
{
    return dir->dd_fd;
}
#endif

/*
 * Make the directory identified by the argument the current directory.
 */
#ifdef MINGW
int
change_to_dir(DIR *dir)
{
    errno = ENOSYS;
    return -1;
}
#else
int
change_to_dir(DIR *dir)
{
    return fchdir(dirfd(dir));
}
#endif

FTS*
fts_open(char * const *path_argv, int options,
         int (*compar)(const FTSENT **, const FTSENT **))
{
    FTS *fts;
    DIR *dir;
    char *cwd;
    int rc;

    if(options != FTS_LOGICAL || compar != NULL || path_argv[1] != NULL) {
        errno = ENOSYS;
        return NULL;
    }

    dir = opendir(path_argv[0]);
    if(dir == NULL)
        return NULL;

    fts = calloc(sizeof(FTS), 1);
    if(fts == NULL) {
        int save = errno;
        closedir(dir);
        errno = save;
        return NULL;
    }

    cwd = getcwd_a();
    if(cwd == NULL) {
        int save = errno;
        free(fts);
        closedir(dir);
        errno = save;
        return NULL;
    }

    rc = change_to_dir(dir);
    if(rc < 0) {
        int save = errno;
        free(cwd);
        free(fts);
        closedir(dir);
        errno = save;
        return NULL;
    }

    fts->depth = 0;
    fts->dir[0] = dir;
    fts->cwd0 = cwd;
    fts->cwd = strdup(path_argv[0]);
    return fts;
}

int
fts_close(FTS *fts)
{
    int save = 0;
    int rc;

    if(fts->ftsent.fts_path) {
        free(fts->ftsent.fts_path);
        fts->ftsent.fts_path = NULL;
    }

    if(fts->dname) {
        free(fts->dname);
        fts->dname = NULL;
    }

    rc = chdir(fts->cwd0);
    if(rc < 0)
        save = errno;

    while(fts->depth >= 0) {
        closedir(fts->dir[fts->depth]);
        fts->depth--;
    }

    free(fts->cwd0);
    if(fts->cwd) free(fts->cwd);
    free(fts);

    if(rc < 0) {
        errno = save;
        return -1;
    }
    return 0;
}

FTSENT *
fts_read(FTS *fts)
{
    struct dirent *dirent;
    int rc;
    char *name;
    char buf[1024];

    if(fts->ftsent.fts_path) {
        free(fts->ftsent.fts_path);
        fts->ftsent.fts_path = NULL;
    }

    if(fts->dname) {
        free(fts->dname);
        fts->dname = NULL;
    }

 again:
    dirent = readdir(fts->dir[fts->depth]);
    if(dirent == NULL) {
        char *newcwd = NULL;
        closedir(fts->dir[fts->depth]);
        fts->dir[fts->depth] = NULL;
        fts->depth--;
        if(fts->depth >= 0) {
            fts->dname = basename_a(fts->cwd);
            if(fts->dname == NULL)
                goto error;
            newcwd = dirname_a(fts->cwd);
            if(newcwd == NULL)
                goto error;
        }
        if(fts->cwd) free(fts->cwd);
        fts->cwd = NULL;
        if(fts->depth < 0)
            return NULL;
        rc = change_to_dir(fts->dir[fts->depth]);
        if(rc < 0) {
            free(newcwd);
            goto error;
        }
        fts->cwd = newcwd;
        name = fts->dname;
        fts->ftsent.fts_info = FTS_DP;
        goto done;
    }

    name = dirent->d_name;

 again2:
    rc = stat(name, &fts->stat);
    if(rc < 0) {
        fts->ftsent.fts_info = FTS_NS;
        goto error2;
    }

    if(S_ISDIR(fts->stat.st_mode)) {
        char *newcwd;
        DIR *dir;

        if(strcmp(name, ".") == 0 || strcmp(name, "..") == 0)
            goto again;

        if(fts->depth >= FTS_MAX_DEPTH) {
            errno = ENFILE;
            goto error;
        }
        dir = opendir(dirent->d_name);
        if(dir == NULL) {
            if(errno == EACCES) {
                fts->ftsent.fts_info = FTS_DNR;
                goto error2;
            } else
                goto error;
        }
        newcwd = mkfilename(fts->cwd, dirent->d_name);
        rc = change_to_dir(dir);
        if(rc < 0) {
            free(newcwd);
            goto error;
        }
        free(fts->cwd);
        fts->cwd = newcwd;
        fts->ftsent.fts_info = FTS_D;
        fts->depth++;
        fts->dir[fts->depth] = dir;
        goto done;
    } else if(S_ISREG(fts->stat.st_mode)) {
        fts->ftsent.fts_info = FTS_F;
        goto done;
#ifdef S_ISLNK
    } else if(S_ISLNK(fts->stat.st_mode)) {
        int rc;
        rc = readlink(name, buf, 1024);
        if(rc < 0)
            goto error;
        if(rc >= 1023) {
            errno = ENAMETOOLONG;
            goto error;
        }
        buf[rc] = '\0';
        name = buf;
        if(access(buf, F_OK) >= 0)
            goto again2;
        fts->ftsent.fts_info = FTS_SLNONE;
        goto done;
#endif
    } else {
        fts->ftsent.fts_info = FTS_DEFAULT;
        goto done;
    }
    
 done:
    if(fts->cwd == NULL)
        fts->cwd = getcwd_a();
    if(fts->cwd == NULL) goto error;
    fts->ftsent.fts_path = mkfilename(fts->cwd, name);
    if(fts->ftsent.fts_path == NULL) goto error;
    fts->ftsent.fts_accpath = name;
    fts->ftsent.fts_statp = &fts->stat;
    return &fts->ftsent;

 error:
    fts->ftsent.fts_info = FTS_ERR;
 error2:
    fts->ftsent.fts_errno = errno;
    return &fts->ftsent;
}