text: /*****************************************************************************
   * vlc_fs.h: File system helpers
   *****************************************************************************
   * Copyright © 2006-2010 Rémi Denis-Courmont
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation; either version 2.1 of the License, or
   * (at your option) any later version.
   *
   * This program 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 Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public License
   * along with this program; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
   *****************************************************************************/
  
  #ifndef VLC_FS_H
  #define VLC_FS_H 1
  
  #include <sys/types.h>
  #include <dirent.h>
  
  struct stat;
  struct iovec;
  
  #ifdef _WIN32
  # include <sys/stat.h>
  # ifndef stat
  #  define stat _stati64
  # endif
  # ifndef fstat
  #  define fstat _fstati64
  # endif
  # ifndef _MSC_VER
  #  undef lseek
  #  define lseek _lseeki64
  # endif
  #endif
  
  #ifdef __ANDROID__
  # define lseek lseek64
  #endif
  
  
  /**
   * \defgroup os Operating system
   * @{
   * \defgroup file File system
   * @{
   *
   * \file
   * The functions in this file help with using low-level Unix-style file
   * descriptors, BSD sockets and directories. In general, they retain the
   * prototype and most semantics from their respective standard equivalents.
   * However, there are a few differences:
   *  - On Windows, file path arguments are expected in UTF-8 format.
   *    They are converted to UTF-16 internally, thus enabling access to paths
   *    outside of the local Windows ANSI code page.
   *  - On POSIX systems, file descriptors are created with the close-on-exec
   *    flag set (atomically where possible), so that they do not leak to
   *    child process after fork-and-exec.
   *  - vlc_scandir(), inspired by GNU scandir(), passes file names rather than
   *    dirent structure pointers to its callbacks.
   *  - vlc_accept() takes an extra boolean for nonblocking mode (compare with
   *    the flags parameter in POSIX.next accept4()).
   *  - Writing functions do not emit a SIGPIPE signal in case of broken pipe.
   *
   * \defgroup fd File descriptors
   * @{
   */
  
  /**
   * Opens a system file handle.
   *
   * @param filename file path to open (with UTF-8 encoding)
   * @param flags open() flags, see the C library open() documentation
   * @return a file handle on success, -1 on error (see errno).
   * @note Contrary to standard open(), this function returns a file handle
   * with the close-on-exec flag preset.
   */
  VLC_API int vlc_open(const char *filename, int flags, ...) VLC_USED;
  
  /**
   * Opens a system file handle relative to an existing directory handle.
   *
   * @param dir directory file descriptor
   * @param filename file path to open (with UTF-8 encoding)
   * @param flags open() flags, see the C library open() documentation
   * @return a file handle on success, -1 on error (see errno).
   * @note Contrary to standard open(), this function returns a file handle
   * with the close-on-exec flag preset.
   */
  VLC_API int vlc_openat(int fd, const char *filename, int flags, ...) VLC_USED;
  
  VLC_API int vlc_mkstemp( char * );
  
  /**
   * Duplicates a file descriptor. The new file descriptor has the close-on-exec
   * descriptor flag preset.
   * @return a new file descriptor, -1 (see errno)
   */
  VLC_API int vlc_dup(int) VLC_USED;
  
  /**
   * Creates a pipe (see "man pipe" for further reference). The new file
   * descriptors have the close-on-exec flag preset.
   * @return 0 on success, -1 on error (see errno)
   */
  VLC_API int vlc_pipe(int [2]) VLC_USED;
  
  /**
   * Creates an anonymous regular file descriptor, i.e. a descriptor for a
   * temporary file.
   *
   * The file is initially empty. The storage space is automatically reclaimed
   * when all file descriptors referencing it are closed.
   *
   * The new file descriptor has the close-on-exec flag preset.
   *
   * @return a file descriptor on success, -1 on error (see errno)
   */
  VLC_API int vlc_memfd(void) VLC_USED;
  
  /**
   * Writes data to a file descriptor. Unlike write(), if EPIPE error occurs,
   * this function does not generate a SIGPIPE signal.
   * @note If the file descriptor is known to be neither a pipe/FIFO nor a
   * connection-oriented socket, the normal write() should be used.
   */
  VLC_API ssize_t vlc_write(int, const void *, size_t);
  
  /**
   * Writes data from an iovec structure to a file descriptor. Unlike writev(),
   * if EPIPE error occurs, this function does not generate a SIGPIPE signal.
   */
  VLC_API ssize_t vlc_writev(int, const struct iovec *, int);
  
  /**
   * Closes a file descriptor.
   *
   * This closes a file descriptor. If this is a last file descriptor for the
   * underlying open file, the file is closed too; the exact semantics depend
   * on the type of file.
   *
   * @note The file descriptor is always closed when the function returns, even
   * if the function returns an error. The sole exception is if the file
   * descriptor was not currently valid, and thus cannot be closed (errno will
   * then be set to EBADF).
   *
   * @param fd file descriptor
   * @return Normally, zero is returned.
   * If an I/O error is detected before or while closing, the function may return
   * -1. Such an error is unrecoverable since the descriptor is closed.
   *
   * A nul return value does not necessarily imply that all pending I/O
   * succeeded, since I/O might still occur asynchronously afterwards.
   */
  VLC_API int vlc_close(int fd);
  
  /**
   * @}
   */
  
  /**
   * Finds file/inode information - like stat().
   * @note As far as possible, fstat() should be used instead.
   *
   * @param filename UTF-8 file path
   */
  VLC_API int vlc_stat(const char *filename, struct stat *) VLC_USED;
  
  /**
   * Finds file/inode information, as lstat().
   * Consider using fstat() instead, if possible.
   *
   * @param filename UTF-8 file path
   */
  VLC_API int vlc_lstat(const char *filename, struct stat *) VLC_USED;
  
  /**
   * Removes a file.
   *
   * @param filename a UTF-8 string with the name of the file you want to delete.
   * @return A 0 return value indicates success. A -1 return value indicates an
   *        error, and an error code is stored in errno
   */
  VLC_API int vlc_unlink(const char *filename);
  
  /**
   * Moves a file atomically. This only works within a single file system.
   *
   * @param oldpath path to the file before the move
   * @param newpath intended path to the file after the move
   * @return A 0 return value indicates success. A -1 return value indicates an
   *        error, and an error code is stored in errno
   */
  VLC_API int vlc_rename(const char *oldpath, const char *newpath);
  
  VLC_API FILE * vlc_fopen( const char *filename, const char *mode ) VLC_USED;
  
  /**
   * \defgroup dir Directories
   * @{
   */
  
  /**
   * Opens a DIR pointer.
   *
   * @param dirname UTF-8 representation of the directory name
   * @return a pointer to the DIR struct, or NULL in case of error.
   * Release with standard closedir().
   */
  VLC_API DIR *vlc_opendir(const char *dirname) VLC_USED;
  
  /**
   * Reads the next file name from an open directory.
   *
   * @param dir directory handle as returned by vlc_opendir()
   *            (must not be used by another thread concurrently)
   *
   * @return a UTF-8 string of the directory entry. The string is valid until
   * the next call to vlc_readdir() or closedir() on the handle.
   * If there are no more entries in the directory, NULL is returned.
   * If an error occurs, errno is set and NULL is returned.
   */
  VLC_API const char *vlc_readdir(DIR *dir) VLC_USED;
  
  VLC_API int vlc_loaddir( DIR *dir, char ***namelist, int (*select)( const char * ), int (*compar)( const char **, const char ** ) );
  VLC_API int vlc_scandir( const char *dirname, char ***namelist, int (*select)( const char * ), int (*compar)( const char **, const char ** ) );
  
  /**
   * Creates a directory.
   *
   * @param dirname a UTF-8 string with the name of the directory that you
   *        want to create.
   * @param mode directory permissions
   * @return 0 on success, -1 on error (see errno).
   */
  VLC_API int vlc_mkdir(const char *dirname, mode_t mode);
  
  /**
   * Determines the current working directory.
   *
   * @return the current working directory (must be free()'d)
   *         or NULL on error
   */
  VLC_API char *vlc_getcwd(void) VLC_USED;
  
  /** @} */
  /** @} */
  
  #if defined( _WIN32 )
  typedef struct vlc_DIR
  {
      _WDIR *wdir; /* MUST be first, see <vlc_fs.h> */
      char *entry;
      union
      {
          DWORD drives;
          bool insert_dot_dot;
      } u;
  } vlc_DIR;
  
  static inline int vlc_closedir( DIR *dir )
  {
      vlc_DIR *vdir = (vlc_DIR *)dir;
      _WDIR *wdir = vdir->wdir;
  
      free( vdir->entry );
      free( vdir );
      return (wdir != NULL) ? _wclosedir( wdir ) : 0;
  }
  # undef closedir
  # define closedir vlc_closedir
  
  static inline void vlc_rewinddir( DIR *dir )
  {
      _WDIR *wdir = *(_WDIR **)dir;
  
      _wrewinddir( wdir );
  }
  # undef rewinddir
  # define rewinddir vlc_rewinddir
  #endif
  
  #ifdef __ANDROID__
  # define lseek lseek64
  #endif
  
  #endif
  