// Copyright (C) 2004-2021 Artifex Software, Inc.

//

// This file is part of MuPDF.

//

// MuPDF is free software: you can redistribute it and/or modify it under the

// terms of the GNU Affero General Public License as published by the Free

// Software Foundation, either version 3 of the License, or (at your option)

// any later version.

//

// MuPDF is distributed in the hope that it will be useful, but WITHOUT ANY

// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

// FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more

// details.

//

// You should have received a copy of the GNU Affero General Public License

// along with MuPDF. If not, see <https://www.gnu.org/licenses/agpl-3.0.en.html>

//

// Alternative licensing terms are available from the licensor.

// For commercial licensing, see <https://www.artifex.com/> or contact

// Artifex Software, Inc., 39 Mesa Street, Suite 108A, San Francisco,

// CA 94129, USA, for further information.

#include "mupdf/fitz.h"

#include <string.h>

#include <errno.h>

#include <sys/stat.h>

#ifdef _MSC_VER

#include <windows.h>

#include <errno.h>

#define stat _stat

#else

#include <dirent.h>

#endif

typedef struct

{

  fz_archive super;

  char *path;

  int max_entries;

  int num_entries;

  char **entries;

} fz_directory;

static void drop_directory(fz_context *ctx, fz_archive *arch)

{

  fz_directory *dir = (fz_directory *) arch;

  int i;

  fz_free(ctx, dir->path);

  for (i = 0; i < dir->num_entries; i++)

    fz_free(ctx, dir->entries[i]);

  fz_free(ctx, dir->entries);

}

static void make_dir_path(char *output, fz_archive *arch, const char *tail, size_t size)

{

  /* Skip any leading ../ path segments, so we don't look outside the

   * directory itself. The paths coming here have already been

   * canonicalized with fz_cleanname so any remaining ".." parts are

   * guaranteed to be at the start of the path.

   */

  fz_directory *dir = (fz_directory *) arch;

  while (tail[0] == '.' && tail[1] == '.' && tail[2] == '/')

    tail += 3;

  fz_strlcpy(output, dir->path, size);

  fz_strlcat(output, "/", size);

  fz_strlcat(output, tail, size);

}

static fz_stream *open_dir_entry(fz_context *ctx, fz_archive *arch, const char *name)

{

  char path[PATH_MAX];

  make_dir_path(path, arch, name, sizeof path);

  return fz_try_open_file(ctx, path);

}

static fz_buffer *read_dir_entry(fz_context *ctx, fz_archive *arch, const char *name)

{

  char path[PATH_MAX];

  make_dir_path(path, arch, name, sizeof path);

  return fz_try_read_file(ctx, path);

}

static int has_dir_entry(fz_context *ctx, fz_archive *arch, const char *name)

{

  char path[PATH_MAX];

  make_dir_path(path, arch, name, sizeof path);

  return fz_file_exists(ctx, path);

}

int

fz_is_directory(fz_context *ctx, const char *path)

{

  struct stat info;

  if (stat(path, &info) < 0)

    return 0;

  return S_ISDIR(info.st_mode);

}

static int

count_dir_entries(fz_context *ctx, fz_archive *arch)

{

  fz_directory *dir = (fz_directory *) arch;

  return dir->num_entries;

}

const char *

list_dir_entry(fz_context *ctx, fz_archive *arch, int n)

{

  fz_directory *dir = (fz_directory *) arch;

  if (n < 0 || n >= dir->num_entries)

    return NULL;

  return dir->entries[n];

}

fz_archive *

fz_open_directory(fz_context *ctx, const char *path)

{

  fz_directory *dir;

#ifdef _MSC_VER

  WCHAR *wpath = NULL;

  size_t z = 3;

  HANDLE h = NULL;

  WIN32_FIND_DATAW dw;

  fz_var(wpath);

  fz_var(h);

#else

  DIR *dp;

  struct dirent *ep;

  fz_var(dp);

#endif

  if (!fz_is_directory(ctx, path))

    fz_throw(ctx, FZ_ERROR_FORMAT, "'%s' is not a directory", path);

  dir = fz_new_derived_archive(ctx, NULL, fz_directory);

  dir->super.format = "dir";

  dir->super.count_entries = count_dir_entries;

  dir->super.list_entry = list_dir_entry;

  dir->super.has_entry = has_dir_entry;

  dir->super.read_entry = read_dir_entry;

  dir->super.open_entry = open_dir_entry;

  dir->super.drop_archive = drop_directory;

  fz_try(ctx)

  {

#ifdef _MSC_VER

    char const *p = path;

    WCHAR *w;

    while (*p)

    {

      int rune;

      p += fz_chartorune(&rune, p);

      if (rune >= 0x10000 || rune < 0)

      {

        errno = EINVAL;

        fz_throw(ctx, FZ_ERROR_SYSTEM, "Unrepresentable UTF-8 char in directory name");

      }

      z++;

    }

    w = wpath = fz_malloc(ctx, z * sizeof(WCHAR));

    p = path;

    while (*p)

    {

      int rune;

      p += fz_chartorune(&rune, p);

      *w++ = rune;

    }

    w[0] = '\\';

    w[1] = '*';

    w[2] = 0;

    /* Now enumerate the paths. */

    h = FindFirstFileW(wpath, &dw);

    if (h == INVALID_HANDLE_VALUE)

      break;

    do

    {

      char *u;

      if (dir->max_entries == dir->num_entries)

      {

        int newmax = dir->max_entries * 2;

        if (newmax == 0)

          newmax = 32;

        dir->entries = fz_realloc(ctx, dir->entries, sizeof(*dir->entries) * newmax);

        dir->max_entries = newmax;

      }

      /* Count the len as utf-8. */

      w = dw.cFileName;

      z = 1;

      while (*w)

        z += fz_runelen(*w++);

      u = dir->entries[dir->num_entries] = fz_malloc(ctx, z);

      dir->num_entries++;

      /* Copy the name across. */

      w = dw.cFileName;

      while (*w)

        u += fz_runetochar(u, *w++);

      *u = 0;

    }

    while (FindNextFileW(h, &dw));

#else

    dp = opendir(path);

    if (dp == NULL)

      break;

    while ((ep = readdir(dp)) != NULL)

    {

      if (dir->max_entries == dir->num_entries)

      {

        int newmax = dir->max_entries * 2;

        if (newmax == 0)

          newmax = 32;

        dir->entries = fz_realloc(ctx, dir->entries, sizeof(*dir->entries) * newmax);

        dir->max_entries = newmax;

      }

      dir->entries[dir->num_entries] = fz_strdup(ctx, ep->d_name);

      dir->num_entries++;

    }

#endif

    dir->path = fz_strdup(ctx, path);

  }

  fz_always(ctx)

  {

#ifdef _MSC_VER

    fz_free(ctx, wpath);

    if (h)

      (void)FindClose(h);

#else

    if (dp)

      (void)closedir(dp);

#endif

  }

  fz_catch(ctx)

  {

    fz_drop_archive(ctx, &dir->super);

    fz_rethrow(ctx);

  }

  return &dir->super;

}