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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.51 by root, Sat Jun 24 19:14:04 2006 UTC vs.
Revision 1.52 by root, Sat Oct 21 23:06:04 2006 UTC

  aio_unlink "/tmp/file", sub { };
  aio_read $fh, 30000, 1024, $buffer, 0, sub {
     $_[0] > 0 or die "read error: $!";
  };
+ use IO::AIO 2; # version has aio objects
+ my $req = aio_unlink "/tmp/file", sub { };
+ $req->cancel; # cancel request if still in queue
  # AnyEvent
  open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
  my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
 syscall has been executed asynchronously.
 All functions expecting a filehandle keep a copy of the filehandle
 internally until the request has finished.
+All non-composite requests (requests that are not broken down into
+multiple requests) return objects of type L<IO::AIO::REQ> that allow
+further manipulation of running requests.
 The pathnames you pass to these routines I<must> be absolute and
 encoded in byte form. The reason for the former is that at the time the
 request is being executed, the current working directory could have
 changed. Alternatively, you can make sure that you never change the
 current working directory.
       print "read $_[0] bytes: <$buffer>\n";
    };
 =item aio_move $srcpath, $dstpath, $callback->($status)
-[EXPERIMENTAL]
-Try to move the I<file> (directories not supported as either source or destination)
+Try to move the I<file> (directories not supported as either source or
-from C<$srcpath> to C<$dstpath> and call the callback with the C<0> (error) or C<-1> ok.
+destination) from C<$srcpath> to C<$dstpath> and call the callback with
+the C<0> (error) or C<-1> ok.
 This is a composite request that tries to rename(2) the file first. If
 rename files with C<EXDEV>, it 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
 The callback a single argument which is either C<undef> or an array-ref
 with the filenames.
 =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
-Scans a directory (similar to C<aio_readdir>) and tries to separate the
+Scans a directory (similar to C<aio_readdir>) but additionally tries to
-entries of directory C<$path> into two sets of names, ones you can recurse
+separate the entries of directory C<$path> into two sets of names, ones
-into (directories), and ones you cannot recurse into (everything else).
+you can recurse into (directories or links to them), and ones you cannot
+recurse into (everything else).
-C<aio_scandir> is a composite request that consists of many
+C<aio_scandir> is a composite request that consists of many sub
-aio-primitives. C<$maxreq> specifies the maximum number of outstanding
+requests. C<$maxreq> specifies the maximum number of outstanding aio
-aio requests that this function generates. If it is C<< <= 0 >>, then a
+requests that this function generates. If it is C<< <= 0 >>, then a
 suitable default will be chosen (currently 8).
 On error, the callback is called without arguments, otherwise it receives
 two array-refs with path-relative entry names.
 Implementation notes.
 The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
 After reading the directory, the modification time, size etc. of the
-directory before and after the readdir is checked, and if they match, the
+directory before and after the readdir is checked, and if they match (and
-link count will be used to decide how many entries are directories (if
+isn't the current time), the link count will be used to decide how many
->= 2). Otherwise, no knowledge of the number of subdirectories will be
+entries are directories (if >= 2). Otherwise, no knowledge of the number
-assumed.
+of subdirectories will be assumed.
-Then entires will be sorted into likely directories (everything without a
+Then entries will be sorted into likely directories (everything without
-non-initial dot) and likely non-directories (everything else).  Then every
+a non-initial dot currently) and likely non-directories (everything
-entry + C</.> will be C<stat>'ed, likely directories first. This is often
+else). Then every entry plus an appended C</.> will be C<stat>'ed,
+likely directories first. If that succeeds, it assumes that the entry
+is a directory or a symlink to directory (which will be checked
+seperately). This is often faster than stat'ing the entry itself because
-faster because filesystems might detect the type of the entry without
+filesystems might detect the type of the entry without reading the inode
-reading the inode data (e.g. ext2fs filetype feature). If that succeeds,
+data (e.g. ext2fs filetype feature).
-it assumes that the entry is a directory or a symlink to directory (which
-will be checked seperately).
-If the known number of directories has been reached, the rest of the
+If the known number of directories (link count - 2) has been reached, the
-entries is assumed to be non-directories.
+rest of the entries is assumed to be non-directories.
+This only works with certainty on POSIX (= UNIX) filesystems, which
+fortunately are the vast majority of filesystems around.
+It will also likely work on non-POSIX filesystems with reduced efficiency
+as those tend to return 0 or 1 as link counts, which disables the
+directory counting heuristic.
 =cut
 sub aio_scandir($$$) {
    my ($path, $maxreq, $cb) = @_;
    $maxreq = 8 if $maxreq <= 0;
    # stat once
    aio_stat $path, sub {
       return $cb->() if $_[0];
+      my $now = time;
       my $hash1 = join ":", (stat _)[0,1,3,7,9];
       # read the directory entries
       aio_readdir $path, sub {
          my $entries = shift
             my $hash2 = join ":", (stat _)[0,1,3,7,9];
             my $ndirs;
             # take the slow route if anything looks fishy
-            if ($hash1 ne $hash2) {
+            if ($hash1 ne $hash2 or (stat _)[9] == $now) {
                $ndirs = -1;
             } else {
                # if nlink == 2, we are finished
                # on non-posix-fs's, we rely on nlink < 2
                $ndirs = (stat _)[3] - 2
 If this call isn't available because your OS lacks it or it couldn't be
 detected, it will be emulated by calling C<fsync> instead.
 =back
+=head2 IO::AIO::CB CLASS
+All non-aggregate C<aio_*> functions return an object of this class when
+called in non-void context.
+A request always moves through the following five states in its lifetime,
+in order: B<ready> (request has been created, but has not been executed
+yet), B<execute> (request is currently being executed), B<pending>
+(request has been executed but callback has not been called yet),
+B<result> (results are being processed synchronously, includes calling the
+callback) and B<done> (request has reached the end of its lifetime and
+holds no resources anymore).
+=over 4
+=item $req->cancel
+Cancels the request, if possible. Has the effect of skipping execution
+when entering the B<execute> state and skipping calling the callback when
+entering the the B<result> state, but will leave the request otherwise
+untouched. That means that requests that currently execute will not be
+stopped and resources held by the request will not be freed prematurely.
+=back
 =head2 SUPPORT FUNCTIONS
 =over 4
 =item $fileno = IO::AIO::poll_fileno
 }
 1;
 =head2 FORK BEHAVIOUR
+This module should do "the right thing" when the process using it forks:
 Before the fork, IO::AIO enters a quiescent state where no requests
 can be added in other threads and no results will be processed. After
 the fork the parent simply leaves the quiescent state and continues
 request/result processing, while the child clears the request/result
 queue (so the requests started before the fork will only be handled in
-the parent). Threats will be started on demand until the limit ste in the
+the parent). Threads will be started on demand until the limit ste in the
 parent process has been reached again.
+In short: the parent will, after a short pause, continue as if fork had
+not been called, while the child will act as if IO::AIO has not been used
+yet.
 =head1 SEE ALSO
-L<Coro>, L<Linux::AIO>.
+L<Coro>, L<Linux::AIO> (obsolete).
 =head1 AUTHOR
  Marc Lehmann <schmorp@schmorp.de>
  http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.51 by root, Sat Jun 24 19:14:04 2006 UTC vs. Revision 1.52 by root, Sat Oct 21 23:06:04 2006 UTC

Diff Legend

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.51 by root, Sat Jun 24 19:14:04 2006 UTC vs.
Revision 1.52 by root, Sat Oct 21 23:06:04 2006 UTC