[ViewVC] Diff of: cvs/IO-AIO/AIO.pm

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.263 by root, Tue Jul 12 20:46:33 2016 UTC vs.
Revision 1.279 by root, Sat Jan 6 01:04:42 2018 UTC

 =head1 NAME
-IO::AIO - Asynchronous Input/Output
+IO::AIO - Asynchronous/Advanced Input/Output
 =head1 SYNOPSIS
  use IO::AIO;
 not well-supported or restricted (GNU/Linux doesn't allow them on normal
 files currently, for example), and they would only support aio_read and
 aio_write, so the remaining functionality would have to be implemented
 using threads anyway.
+In addition to asynchronous I/O, this module also exports some rather
+arcane interfaces, such as C<madvise> or linux's C<splice> system call,
+which is why the C<A> in C<AIO> can also mean I<advanced>.
 Although the module will work in the presence of other (Perl-) threads,
 it is currently not reentrant in any way, so use appropriate locking
 yourself, always call C<poll_cb> from within the same thread, or never
 call C<poll_cb> (or other C<aio_> functions) recursively.
 use common::sense;
 use base 'Exporter';
 BEGIN {
-   our $VERSION = 4.34;
+   our $VERSION = 4.4;
    our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
                      aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
                      aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
                      aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
                      aio_pathsync aio_readahead aio_fiemap aio_allocate
-                     aio_rename aio_link aio_move aio_copy aio_group
+                     aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
                      aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
                      aio_chmod aio_utime aio_truncate
                      aio_msync aio_mtouch aio_mlock aio_mlockall
                      aio_statvfs
+                     aio_slurp
                      aio_wd);
    our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
    our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
                        min_parallel max_parallel max_idle idle_timeout
    aio_link $srcpath, $dstpath, $callback->($status)
    aio_symlink $srcpath, $dstpath, $callback->($status)
    aio_readlink $pathname, $callback->($link)
    aio_realpath $pathname, $callback->($path)
    aio_rename $srcpath, $dstpath, $callback->($status)
+   aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
    aio_mkdir $pathname, $mode, $callback->($status)
    aio_rmdir $pathname, $callback->($status)
    aio_readdir $pathname, $callback->($entries)
    aio_readdirx $pathname, $flags, $callback->($entries, $flags)
       IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
    aio_syncfs $fh, $callback->($status)
    aio_fsync $fh, $callback->($status)
    aio_fdatasync $fh, $callback->($status)
    aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
    aio_pathsync $pathname, $callback->($status)
-   aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
+   aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
    aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
    aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
    aio_mlockall $flags, $callback->($status)
    aio_group $callback->(...)
    aio_nop $callback->()
    IO::AIO::idle_timeout $seconds
    IO::AIO::max_outstanding $maxreqs
    IO::AIO::nreqs
    IO::AIO::nready
    IO::AIO::npending
+   $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
+   IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
    IO::AIO::sendfile $ofh, $ifh, $offset, $count
    IO::AIO::fadvise $fh, $offset, $len, $advice
    IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
    IO::AIO::munmap $scalar
 =item aio_read  $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
 =item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
 Reads or writes C<$length> bytes from or to the specified C<$fh> and
-C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
+C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
-and calls the callback without the actual number of bytes read (or -1 on
+calls the callback with the actual number of bytes transferred (or -1 on
 error, just like the syscall).
 C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
 offset plus the actual number of bytes read.
 C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
 space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
 to deallocate a file range.
 IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
-(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see
+(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
-your L<fallocate(2)> manpage).
+C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
+to unshare shared blocks (see your L<fallocate(2)> manpage).
 The file system block size used by C<fallocate> is presumably the
-C<f_bsize> returned by C<statvfs>.
+C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
+can dictate other limitations.
 If C<fallocate> isn't available or cannot be emulated (currently no
 emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
 rename(2) and call the callback with the result code.
 On systems that support the AIO::WD working directory abstraction
 natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
 of failing, C<rename> is called on the absolute path of C<$wd>.
+=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
+Basically a version of C<aio_rename> with an additional C<$flags>
+argument. Calling this with C<$flags=0> is the same as calling
+C<aio_rename>.
+Non-zero flags are currently only supported on GNU/Linux systems that
+support renameat2. Other systems fail with C<ENOSYS> in this case.
+The following constants are available (missing ones are, as usual C<0>),
+see renameat2(2) for details:
+C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
+and C<IO::AIO::RENAME_WHITEOUT>.
 =item aio_mkdir $pathname, $mode, $callback->($status)
 Asynchronously mkdir (create) a directory and call the callback with
 C<$type>'s are known, which can be used to speed up some algorithms.
 =back
+=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
+Opens, reads and closes the given file. The data is put into C<$data>,
+which is resized as required.
+If C<$offset> is negative, then it is counted from the end of the file.
+If C<$length> is zero, then the remaining length of the file is
+used. Also, in this case, the same limitations to modifying C<$data> apply
+as when IO::AIO::mmap is used, i.e. it must only be modified in-place
+with C<substr>. If the size of the file is known, specifying a non-zero
+C<$length> results in a performance advantage.
+This request is similar to the older C<aio_load> request, but since it is
+a single request, it might be more efficient to use.
+Example: load F</etc/passwd> into C<$passwd>.
+   my $passwd;
+   aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
+      $_[0] >= 0
+         or die "/etc/passwd: $!\n";
+      printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
+      print $passwd;
+   };
+   IO::AIO::flush;
 =item aio_load $pathname, $data, $callback->($status)
 This is a composite request that tries to fully load the given file into
 memory. Status is the same as with aio_read.
+Using C<aio_slurp> might be more efficient, as it is a single request.
 =cut
 sub aio_load($$;$) {
    my ($path, undef, $cb) = @_;
 =item aio_copy $srcpath, $dstpath, $callback->($status)
 Try to copy the I<file> (directories not supported as either source or
 destination) from C<$srcpath> to C<$dstpath> and call the callback with
 a status of C<0> (ok) or C<-1> (error, see C<$!>).
+Existing destination files will be truncated.
 This is a composite request that creates the destination file with
 mode 0200 and copies the contents of the source file into it using
 C<aio_sendfile>, followed by restoring atime, mtime, access mode and
 uid/gid, in that order.
 Scans a directory (similar to C<aio_readdir>) but additionally tries to
 efficiently separate the entries of directory C<$path> into two sets of
 names, directories you can recurse into (directories), and ones you cannot
 recurse into (everything else, including symlinks to directories).
-C<aio_scandir> is a composite request that creates of many sub requests_
+C<aio_scandir> is a composite request that generates many sub requests.
 C<$maxreq> specifies the maximum number of outstanding aio requests that
 this function generates. If it is C<< <= 0 >>, then a suitable default
 will be chosen (currently 4).
 On error, the callback is called without arguments, otherwise it receives
 So in general, you should only use these calls for things that do
 (filesystem) I/O, not for things that wait for other events (network,
 other processes), although if you are careful and know what you are doing,
 you still can.
+The following constants are available (missing ones are, as usual C<0>):
+C<F_DUPFD_CLOEXEC>,
+C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
+C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
+C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
+C<FS_IOC_FIEMAP>.
+C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
+C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
+C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
+C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
+C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
+C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
+C<FS_FL_USER_MODIFIABLE>.
+C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
+C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
+C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
+C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
 =item aio_sync $callback->($status)
 Asynchronously call sync and call the callback when finished.
 =item aio_fsync $fh, $callback->($status)
    };
    $grp
 }
-=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
+=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
 This is a rather advanced IO::AIO call, which only works on mmap(2)ed
 scalars (see the C<IO::AIO::mmap> function, although it also works on data
 scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
 scalar must only be modified in-place while an aio operation is pending on
 It calls the C<msync> function of your OS, if available, with the memory
 area starting at C<$offset> in the string and ending C<$length> bytes
 later. If C<$length> is negative, counts from the end, and if C<$length>
 is C<undef>, then it goes till the end of the string. The flags can be
-a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
+either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
-C<IO::AIO::MS_SYNC>.
+C<IO::AIO::MS_INVALIDATE>.
 =item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
 This is a rather advanced IO::AIO call, which works best on mmap(2)ed
 scalars.
 C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
 C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
 C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
 C<IO::AIO::FIEMAP_EXTENT_SHARED>.
-At the time of this writing (Linux 3.2), this requets is unreliable unless
+At the time of this writing (Linux 3.2), this request is unreliable unless
 C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
-it to return all extents of a range for files with large number of
+it to return all extents of a range for files with a large number of
-extents. The code works around all these issues if C<$count> is undef.
+extents. The code (only) works around all these issues if C<$count> is
+C<undef>.
 =item aio_group $callback->(...)
 This is a very special aio request: Instead of doing something, it is a
 container for other aio requests, which is useful if you want to bundle
 There are some caveats: when directories get renamed (or deleted), the
 pathname string doesn't change, so will point to the new directory (or
 nowhere at all), while the directory fd, if available on the system,
 will still point to the original directory. Most functions accepting a
 pathname will use the directory fd on newer systems, and the string on
-older systems. Some functions (such as realpath) will always rely on the
+older systems. Some functions (such as C<aio_realpath>) will always rely on
-string form of the pathname.
+the string form of the pathname.
 So this functionality is mainly useful to get some protection against
 C<chdir>, to easily get an absolute path out of a relative path for future
 reference, and to speed up doing many operations in the same directory
 (e.g. when stat'ing all files in a directory).
 This is a very bad function to use in interactive programs because it
 blocks, and a bad way to reduce concurrency because it is inexact: Better
 use an C<aio_group> together with a feed callback.
 Its main use is in scripts without an event loop - when you want to stat
-a lot of files, you can write somehting like this:
+a lot of files, you can write something like this:
    IO::AIO::max_outstanding 32;
    for my $path (...) {
       aio_stat $path , ...;
 some "Advanced I/O" function not available to in Perl, without going the
 "Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
 counterpart.
 =over 4
+=item $numfd = IO::AIO::get_fdlimit
+This function is I<EXPERIMENTAL> and subject to change.
+Tries to find the current file descriptor limit and returns it, or
+C<undef> and sets C<$!> in case of an error. The limit is one larger than
+the highest valid file descriptor number.
+=item IO::AIO::min_fdlimit [$numfd]
+This function is I<EXPERIMENTAL> and subject to change.
+Try to increase the current file descriptor limit(s) to at least C<$numfd>
+by changing the soft or hard file descriptor resource limit. If C<$numfd>
+is missing, it will try to set a very high limit, although this is not
+recommended when you know the actual minimum that you require.
+If the limit cannot be raised enough, the function makes a best-effort
+attempt to increase the limit as much as possible, using various
+tricks, while still failing. You can query the resulting limit using
+C<IO::AIO::get_fdlimit>.
+If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
+true.
 =item IO::AIO::sendfile $ofh, $ifh, $offset, $count
 Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
 but is blocking (this makes most sense if you know the input data is
 =item IO::AIO::madvise $scalar, $offset, $len, $advice
 Simply calls the C<posix_madvise> function (see its
 manpage for details). The following advice constants are
 available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
-C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>,
+C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
-C<IO::AIO::MADV_FREE>.
+C<IO::AIO::MADV_DONTNEED>.
+If C<$offset> is negative, counts from the end. If C<$length> is negative,
+the remaining length of the C<$scalar> is used. If possible, C<$length>
+will be reduced to fit into the C<$scalar>.
 On systems that do not implement C<posix_madvise>, this function returns
 ENOSYS, otherwise the return value of C<posix_madvise>.
 =item IO::AIO::mprotect $scalar, $offset, $len, $protect
 Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
 $scalar (see its manpage for details). The following protect
 constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
 C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
+If C<$offset> is negative, counts from the end. If C<$length> is negative,
+the remaining length of the C<$scalar> is used. If possible, C<$length>
+will be reduced to fit into the C<$scalar>.
 On systems that do not implement C<mprotect>, this function returns
 ENOSYS, otherwise the return value of C<mprotect>.
 =item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
 Memory-maps a file (or anonymous memory range) and attaches it to the
 given C<$scalar>, which will act like a string scalar. Returns true on
 success, and false otherwise.
+The scalar must exist, but its contents do not matter - this means you
+cannot use a nonexistant array or hash element. When in doubt, C<undef>
+the scalar first.
-The only operations allowed on the scalar are C<substr>/C<vec> that don't
+The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
-change the string length, and most read-only operations such as copying it
+which don't change the string length, and most read-only operations such
-or searching it with regexes and so on.
+as copying it or searching it with regexes and so on.
 Anything else is unsafe and will, at best, result in memory leaks.
 The memory map associated with the C<$scalar> is automatically removed
-when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
+when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
-C<IO::AIO::munmap> functions are called.
+or C<IO::AIO::munmap> functions are called on it.
 This calls the C<mmap>(2) function internally. See your system's manual
 page for details on the C<$length>, C<$prot> and C<$flags> parameters.
 The C<$length> must be larger than zero and smaller than the actual

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.263 by root, Tue Jul 12 20:46:33 2016 UTC vs. Revision 1.279 by root, Sat Jan 6 01:04:42 2018 UTC

Diff Legend

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.263 by root, Tue Jul 12 20:46:33 2016 UTC vs.
Revision 1.279 by root, Sat Jan 6 01:04:42 2018 UTC