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Revision 1.21 by root, Fri Dec 22 04:05:50 2006 UTC vs.
Revision 1.24 by root, Sun Aug 5 16:45:54 2007 UTC

61 faster on a RAID volume or over NFS when you do a number of stat 61 faster on a RAID volume or over NFS when you do a number of stat
62 operations concurrently. 62 operations concurrently.
63 63
64 While most of this works on all types of file descriptors (for example 64 While most of this works on all types of file descriptors (for example
65 sockets), using these functions on file descriptors that support 65 sockets), using these functions on file descriptors that support
66 nonblocking operation (again, sockets, pipes etc.) is very inefficient 66 nonblocking operation (again, sockets, pipes etc.) is very inefficient.
67 or might not work (aio_read fails on sockets/pipes/fifos). Use an event
68 loop for that (such as the Event module): IO::AIO will naturally fit 67 Use an event loop for that (such as the Event module): IO::AIO will
69 into such an event loop itself. 68 naturally fit into such an event loop itself.
70 69
71 In this version, a number of threads are started that execute your 70 In this version, a number of threads are started that execute your
72 requests and signal their completion. You don't need thread support in 71 requests and signal their completion. You don't need thread support in
73 perl, and the threads created by this module will not be visible to 72 perl, and the threads created by this module will not be visible to
74 perl. In the future, this module might make use of the native aio 73 perl. In the future, this module might make use of the native aio
76 not well-supported or restricted (GNU/Linux doesn't allow them on normal 75 not well-supported or restricted (GNU/Linux doesn't allow them on normal
77 files currently, for example), and they would only support aio_read and 76 files currently, for example), and they would only support aio_read and
78 aio_write, so the remaining functionality would have to be implemented 77 aio_write, so the remaining functionality would have to be implemented
79 using threads anyway. 78 using threads anyway.
80 79
81 Although the module will work with in the presence of other (Perl-) 80 Although the module will work in the presence of other (Perl-) threads,
82 threads, it is currently not reentrant in any way, so use appropriate 81 it is currently not reentrant in any way, so use appropriate locking
83 locking yourself, always call "poll_cb" from within the same thread, or 82 yourself, always call "poll_cb" from within the same thread, or never
84 never call "poll_cb" (or other "aio_" functions) recursively. 83 call "poll_cb" (or other "aio_" functions) recursively.
85 84
86 EXAMPLE 85 EXAMPLE
87 This is a simple example that uses the Event module and loads 86 This is a simple example that uses the Event module and loads
88 /etc/passwd asynchronously: 87 /etc/passwd asynchronously:
89 88
242 They are the same as used by "sysopen". 241 They are the same as used by "sysopen".
243 242
244 Likewise, $mode specifies the mode of the newly created file, if it 243 Likewise, $mode specifies the mode of the newly created file, if it
245 didn't exist and "O_CREAT" has been given, just like perl's 244 didn't exist and "O_CREAT" has been given, just like perl's
246 "sysopen", except that it is mandatory (i.e. use 0 if you don't 245 "sysopen", except that it is mandatory (i.e. use 0 if you don't
247 create new files, and 0666 or 0777 if you do). 246 create new files, and 0666 or 0777 if you do). Note that the $mode
247 will be modified by the umask in effect then the request is being
248 executed, so better never change the umask.
248 249
249 Example: 250 Example:
250 251
251 aio_open "/etc/passwd", O_RDONLY, 0, sub { 252 aio_open "/etc/passwd", O_RDONLY, 0, sub {
252 if ($_[0]) { 253 if ($_[0]) {
267 This is supposed to be a bug in the API, so that might change. It's 268 This is supposed to be a bug in the API, so that might change. It's
268 therefore best to avoid this function. 269 therefore best to avoid this function.
269 270
270 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 271 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
271 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 272 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
272 Reads or writes "length" bytes from the specified "fh" and "offset" 273 Reads or writes $length bytes from the specified $fh and $offset
273 into the scalar given by "data" and offset "dataoffset" and calls 274 into the scalar given by $data and offset $dataoffset and calls the
274 the callback without the actual number of bytes read (or -1 on 275 callback without the actual number of bytes read (or -1 on error,
275 error, just like the syscall). 276 just like the syscall).
277
278 If $offset is undefined, then the current file offset will be used
279 (and updated), otherwise the file offset will not be changed by
280 these calls.
281
282 If $length is undefined in "aio_write", use the remaining length of
283 $data.
284
285 If $dataoffset is less than zero, it will be counted from the end of
286 $data.
276 287
277 The $data scalar *MUST NOT* be modified in any way while the request 288 The $data scalar *MUST NOT* be modified in any way while the request
278 is outstanding. Modifying it can result in segfaults or WW3 (if the 289 is outstanding. Modifying it can result in segfaults or World War
279 necessary/optional hardware is installed). 290 III (if the necessary/optional hardware is installed).
280 291
281 Example: Read 15 bytes at offset 7 into scalar $buffer, starting at 292 Example: Read 15 bytes at offset 7 into scalar $buffer, starting at
282 offset 0 within the scalar: 293 offset 0 within the scalar:
283 294
284 aio_read $fh, 7, 15, $buffer, 0, sub { 295 aio_read $fh, 7, 15, $buffer, 0, sub {
342 aio_stat "/etc/passwd", sub { 353 aio_stat "/etc/passwd", sub {
343 $_[0] and die "stat failed: $!"; 354 $_[0] and die "stat failed: $!";
344 print "size is ", -s _, "\n"; 355 print "size is ", -s _, "\n";
345 }; 356 };
346 357
358 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
359 Works like perl's "utime" function (including the special case of
360 $atime and $mtime being undef). Fractional times are supported if
361 the underlying syscalls support them.
362
363 When called with a pathname, uses utimes(2) if available, otherwise
364 utime(2). If called on a file descriptor, uses futimes(2) if
365 available, otherwise returns ENOSYS, so this is not portable.
366
367 Examples:
368
369 # set atime and mtime to current time (basically touch(1)):
370 aio_utime "path", undef, undef;
371 # set atime to current time and mtime to beginning of the epoch:
372 aio_utime "path", time, undef; # undef==0
373
374 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
375 Works like perl's "chown" function, except that "undef" for either
376 $uid or $gid is being interpreted as "do not change" (but -1 can
377 also be used).
378
379 Examples:
380
381 # same as "chown root path" in the shell:
382 aio_chown "path", 0, -1;
383 # same as above:
384 aio_chown "path", 0, undef;
385
386 aio_truncate $fh_or_path, $offset, $callback->($status)
387 Works like truncate(2) or ftruncate(2).
388
389 aio_chmod $fh_or_path, $mode, $callback->($status)
390 Works like perl's "chmod" function.
391
347 aio_unlink $pathname, $callback->($status) 392 aio_unlink $pathname, $callback->($status)
348 Asynchronously unlink (delete) a file and call the callback with the 393 Asynchronously unlink (delete) a file and call the callback with the
349 result code. 394 result code.
350 395
351 aio_mknod $path, $mode, $dev, $callback->($status) 396 aio_mknod $path, $mode, $dev, $callback->($status)
373 418
374 aio_rename $srcpath, $dstpath, $callback->($status) 419 aio_rename $srcpath, $dstpath, $callback->($status)
375 Asynchronously rename the object at $srcpath to $dstpath, just as 420 Asynchronously rename the object at $srcpath to $dstpath, just as
376 rename(2) and call the callback with the result code. 421 rename(2) and call the callback with the result code.
377 422
423 aio_mkdir $pathname, $mode, $callback->($status)
424 Asynchronously mkdir (create) a directory and call the callback with
425 the result code. $mode will be modified by the umask at the time the
426 request is executed, so do not change your umask.
427
378 aio_rmdir $pathname, $callback->($status) 428 aio_rmdir $pathname, $callback->($status)
379 Asynchronously rmdir (delete) a directory and call the callback with 429 Asynchronously rmdir (delete) a directory and call the callback with
380 the result code. 430 the result code.
381 431
382 aio_readdir $pathname, $callback->($entries) 432 aio_readdir $pathname, $callback->($entries)
384 entire directory (i.e. opendir + readdir + closedir). The entries 434 entire directory (i.e. opendir + readdir + closedir). The entries
385 will not be sorted, and will NOT include the "." and ".." entries. 435 will not be sorted, and will NOT include the "." and ".." entries.
386 436
387 The callback a single argument which is either "undef" or an 437 The callback a single argument which is either "undef" or an
388 array-ref with the filenames. 438 array-ref with the filenames.
439
440 aio_load $path, $data, $callback->($status)
441 This is a composite request that tries to fully load the given file
442 into memory. Status is the same as with aio_read.
389 443
390 aio_copy $srcpath, $dstpath, $callback->($status) 444 aio_copy $srcpath, $dstpath, $callback->($status)
391 Try to copy the *file* (directories not supported as either source 445 Try to copy the *file* (directories not supported as either source
392 or destination) from $srcpath to $dstpath and call the callback with 446 or destination) from $srcpath to $dstpath and call the callback with
393 the 0 (error) or -1 ok. 447 the 0 (error) or -1 ok.
461 515
462 It will also likely work on non-POSIX filesystems with reduced 516 It will also likely work on non-POSIX filesystems with reduced
463 efficiency as those tend to return 0 or 1 as link counts, which 517 efficiency as those tend to return 0 or 1 as link counts, which
464 disables the directory counting heuristic. 518 disables the directory counting heuristic.
465 519
520 aio_rmtree $path, $callback->($status)
521 Delete a directory tree starting (and including) $path, return the
522 status of the final "rmdir" only. This is a composite request that
523 uses "aio_scandir" to recurse into and rmdir directories, and unlink
524 everything else.
525
466 aio_fsync $fh, $callback->($status) 526 aio_fsync $fh, $callback->($status)
467 Asynchronously call fsync on the given filehandle and call the 527 Asynchronously call fsync on the given filehandle and call the
468 callback with the fsync result code. 528 callback with the fsync result code.
469 529
470 aio_fdatasync $fh, $callback->($status) 530 aio_fdatasync $fh, $callback->($status)

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