include/vlc_fs.h

   1 /*****************************************************************************
   2  * vlc_fs.h: File system helpers
   3  *****************************************************************************
   4  * Copyright © 2006-2010 Rémi Denis-Courmont
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 #ifndef VLC_FS_H
  22 #define VLC_FS_H 1
  23
  24 #include <sys/types.h>
  25 #include <dirent.h>
  26
  27 struct stat;
  28 struct iovec;
  29
  30 #ifdef _WIN32
  31 # include <sys/stat.h>
  32 # ifndef stat
  33 #  define stat _stati64
  34 # endif
  35 # ifndef fstat
  36 #  define fstat _fstati64
  37 # endif
  38 # ifndef _MSC_VER
  39 #  undef lseek
  40 #  define lseek _lseeki64
  41 # endif
  42 #endif
  43
  44 #ifdef __ANDROID__
  45 # define lseek lseek64
  46 #endif
  47
  48
  49 /**
  50  * \defgroup os Operating system
  51  * \ingroup vlc
  52  * \defgroup file File system
  53  * \ingroup os
  54  * @{
  55  *
  56  * \file
  57  * The functions in this file help with using low-level Unix-style file
  58  * descriptors, BSD sockets and directories. In general, they retain the
  59  * prototype and most semantics from their respective standard equivalents.
  60  * However, there are a few differences:
  61  *  - On Windows, file path arguments are expected in UTF-8 format.
  62  *    They are converted to UTF-16 internally, thus enabling access to paths
  63  *    outside of the local Windows ANSI code page.
  64  *  - On POSIX systems, file descriptors are created with the close-on-exec
  65  *    flag set (atomically where possible), so that they do not leak to
  66  *    child process after fork-and-exec.
  67  *  - vlc_scandir(), inspired by GNU scandir(), passes file names rather than
  68  *    dirent structure pointers to its callbacks.
  69  *  - vlc_accept() takes an extra boolean for nonblocking mode (compare with
  70  *    the flags parameter in POSIX.next accept4()).
  71  *  - Writing functions do not emit a SIGPIPE signal in case of broken pipe.
  72  *
  73  * \defgroup fd File descriptors
  74  * @{
  75  */
  76
  77 /**
  78  * Opens a system file handle.
  79  *
  80  * @param filename file path to open (with UTF-8 encoding)
  81  * @param flags open() flags, see the C library open() documentation
  82  * @return a file handle on success, -1 on error (see errno).
  83  * @note Contrary to standard open(), this function returns a file handle
  84  * with the close-on-exec flag preset.
  85  */
  86 VLC_API int vlc_open(const char *filename, int flags, ...) VLC_USED;
  87
  88 /**
  89  * Opens a system file handle relative to an existing directory handle.
  90  *
  91  * @param dir directory file descriptor
  92  * @param filename file path to open (with UTF-8 encoding)
  93  * @param flags open() flags, see the C library open() documentation
  94  * @return a file handle on success, -1 on error (see errno).
  95  * @note Contrary to standard open(), this function returns a file handle
  96  * with the close-on-exec flag preset.
  97  */
  98 VLC_API int vlc_openat(int fd, const char *filename, int flags, ...) VLC_USED;
  99
 100 VLC_API int vlc_mkstemp( char * );
 101
 102 /**
 103  * Duplicates a file descriptor. The new file descriptor has the close-on-exec
 104  * descriptor flag preset.
 105  * @return a new file descriptor, -1 (see errno)
 106  */
 107 VLC_API int vlc_dup(int) VLC_USED;
 108
 109 /**
 110  * Creates a pipe (see "man pipe" for further reference). The new file
 111  * descriptors have the close-on-exec flag preset.
 112  * @return 0 on success, -1 on error (see errno)
 113  */
 114 VLC_API int vlc_pipe(int [2]) VLC_USED;
 115
 116 /**
 117  * Creates an anonymous regular file descriptor, i.e. a descriptor for a
 118  * temporary file.
 119  *
 120  * The file is initially empty. The storage space is automatically reclaimed
 121  * when all file descriptors referencing it are closed.
 122  *
 123  * The new file descriptor has the close-on-exec flag preset.
 124  *
 125  * @return a file descriptor on success, -1 on error (see errno)
 126  */
 127 VLC_API int vlc_memfd(void) VLC_USED;
 128
 129 /**
 130  * Writes data to a file descriptor. Unlike write(), if EPIPE error occurs,
 131  * this function does not generate a SIGPIPE signal.
 132  * @note If the file descriptor is known to be neither a pipe/FIFO nor a
 133  * connection-oriented socket, the normal write() should be used.
 134  */
 135 VLC_API ssize_t vlc_write(int, const void *, size_t);
 136
 137 /**
 138  * Writes data from an iovec structure to a file descriptor. Unlike writev(),
 139  * if EPIPE error occurs, this function does not generate a SIGPIPE signal.
 140  */
 141 VLC_API ssize_t vlc_writev(int, const struct iovec *, int);
 142
 143 /**
 144  * Closes a file descriptor.
 145  *
 146  * This closes a file descriptor. If this is a last file descriptor for the
 147  * underlying open file, the file is closed too; the exact semantics depend
 148  * on the type of file.
 149  *
 150  * @note The file descriptor is always closed when the function returns, even
 151  * if the function returns an error. The sole exception is if the file
 152  * descriptor was not currently valid, and thus cannot be closed (errno will
 153  * then be set to EBADF).
 154  *
 155  * @param fd file descriptor
 156  * @return Normally, zero is returned.
 157  * If an I/O error is detected before or while closing, the function may return
 158  * -1. Such an error is unrecoverable since the descriptor is closed.
 159  *
 160  * A nul return value does not necessarily imply that all pending I/O
 161  * succeeded, since I/O might still occur asynchronously afterwards.
 162  */
 163 VLC_API int vlc_close(int fd);
 164
 165 /**
 166  * @}
 167  */
 168
 169 /**
 170  * Finds file/inode information - like stat().
 171  * @note As far as possible, fstat() should be used instead.
 172  *
 173  * @param filename UTF-8 file path
 174  */
 175 VLC_API int vlc_stat(const char *filename, struct stat *) VLC_USED;
 176
 177 /**
 178  * Finds file/inode information, as lstat().
 179  * Consider using fstat() instead, if possible.
 180  *
 181  * @param filename UTF-8 file path
 182  */
 183 VLC_API int vlc_lstat(const char *filename, struct stat *) VLC_USED;
 184
 185 /**
 186  * Removes a file.
 187  *
 188  * @param filename a UTF-8 string with the name of the file you want to delete.
 189  * @return A 0 return value indicates success. A -1 return value indicates an
 190  *        error, and an error code is stored in errno
 191  */
 192 VLC_API int vlc_unlink(const char *filename);
 193
 194 /**
 195  * Moves a file atomically. This only works within a single file system.
 196  *
 197  * @param oldpath path to the file before the move
 198  * @param newpath intended path to the file after the move
 199  * @return A 0 return value indicates success. A -1 return value indicates an
 200  *        error, and an error code is stored in errno
 201  */
 202 VLC_API int vlc_rename(const char *oldpath, const char *newpath);
 203
 204 VLC_API FILE * vlc_fopen( const char *filename, const char *mode ) VLC_USED;
 205
 206 /**
 207  * \defgroup dir Directories
 208  * @{
 209  */
 210
 211 /**
 212  * Opens a DIR pointer.
 213  *
 214  * @param dirname UTF-8 representation of the directory name
 215  * @return a pointer to the DIR struct, or NULL in case of error.
 216  * Release with standard closedir().
 217  */
 218 VLC_API DIR *vlc_opendir(const char *dirname) VLC_USED;
 219
 220 /**
 221  * Reads the next file name from an open directory.
 222  *
 223  * @param dir directory handle as returned by vlc_opendir()
 224  *            (must not be used by another thread concurrently)
 225  *
 226  * @return a UTF-8 string of the directory entry. The string is valid until
 227  * the next call to vlc_readdir() or closedir() on the handle.
 228  * If there are no more entries in the directory, NULL is returned.
 229  * If an error occurs, errno is set and NULL is returned.
 230  */
 231 VLC_API const char *vlc_readdir(DIR *dir) VLC_USED;
 232
 233 VLC_API int vlc_loaddir( DIR *dir, char ***namelist, int (*select)( const char * ), int (*compar)( const char **, const char ** ) );
 234 VLC_API int vlc_scandir( const char *dirname, char ***namelist, int (*select)( const char * ), int (*compar)( const char **, const char ** ) );
 235
 236 /**
 237  * Creates a directory.
 238  *
 239  * @param dirname a UTF-8 string with the name of the directory that you
 240  *        want to create.
 241  * @param mode directory permissions
 242  * @return 0 on success, -1 on error (see errno).
 243  */
 244 VLC_API int vlc_mkdir(const char *dirname, mode_t mode);
 245
 246 /**
 247  * Determines the current working directory.
 248  *
 249  * @return the current working directory (must be free()'d)
 250  *         or NULL on error
 251  */
 252 VLC_API char *vlc_getcwd(void) VLC_USED;
 253
 254 /** @} */
 255
 256 #if defined( _WIN32 )
 257 typedef struct vlc_DIR
 258 {
 259     _WDIR *wdir; /* MUST be first, see <vlc_fs.h> */
 260     char *entry;
 261     union
 262     {
 263         DWORD drives;
 264         bool insert_dot_dot;
 265     } u;
 266 } vlc_DIR;
 267
 268 static inline int vlc_closedir( DIR *dir )
 269 {
 270     vlc_DIR *vdir = (vlc_DIR *)dir;
 271     _WDIR *wdir = vdir->wdir;
 272
 273     free( vdir->entry );
 274     free( vdir );
 275     return (wdir != NULL) ? _wclosedir( wdir ) : 0;
 276 }
 277 # undef closedir
 278 # define closedir vlc_closedir
 279
 280 static inline void vlc_rewinddir( DIR *dir )
 281 {
 282     _WDIR *wdir = *(_WDIR **)dir;
 283
 284     _wrewinddir( wdir );
 285 }
 286 # undef rewinddir
 287 # define rewinddir vlc_rewinddir
 288 #endif
 289
 290 #ifdef __ANDROID__
 291 # define lseek lseek64
 292 #endif
 293
 294 #endif