--- IO-AIO/AIO.pm 2006/10/24 17:22:17 1.74 +++ IO-AIO/AIO.pm 2006/10/28 00:17:30 1.84 @@ -133,10 +133,10 @@ our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move - aio_group aio_nop); + aio_copy aio_group aio_nop aio_mknod); 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_outstanding nreqs); + min_parallel max_parallel nreqs nready npending); @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; @@ -177,13 +177,16 @@ =over 4 -=item aioreq_pri $pri +=item $prev_pri = aioreq_pri [$pri] -Sets the priority for the next aio request. The default priority -is C<0>, the minimum and maximum priorities are C<-4> and C<4>, -respectively. Requests with higher priority will be serviced first. +Returns the priority value that would be used for the next request and, if +C<$pri> is given, sets the priority for the next aio request. -The priority will be reset to C<0> after each call to one of the C +The default priority is C<0>, the minimum and maximum priorities are C<-4> +and C<4>, respectively. Requests with higher priority will be serviced +first. + +The priority will be reset to C<0> after each call to one of the C functions. Example: open a file with low priority, then read something from it with @@ -264,74 +267,6 @@ print "read $_[0] bytes: <$buffer>\n"; }; -=item aio_move $srcpath, $dstpath, $callback->($status) - -Try to move the I (directories not supported as either source or -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, it creates the destination file with mode 0200 -and copies the contents of the source file into it using C, -followed by restoring atime, mtime, access mode and uid/gid, in that -order, and unlinking the C<$srcpath>. - -If an error occurs, the partial destination file will be unlinked, if -possible, except when setting atime, mtime, access mode and uid/gid, where -errors are being ignored. - -=cut - -sub aio_move($$$) { - my ($src, $dst, $cb) = @_; - - my $grp = aio_group $cb; - - add $grp aio_rename $src, $dst, sub { - if ($_[0] && $! == EXDEV) { - add $grp aio_open $src, O_RDONLY, 0, sub { - if (my $src_fh = $_[0]) { - my @stat = stat $src_fh; - - add $grp aio_open $dst, O_WRONLY, 0200, sub { - if (my $dst_fh = $_[0]) { - add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { - close $src_fh; - - if ($_[0] == $stat[7]) { - utime $stat[8], $stat[9], $dst; - chmod $stat[2] & 07777, $dst_fh; - chown $stat[4], $stat[5], $dst_fh; - close $dst_fh; - - add $grp aio_unlink $src, sub { - $grp->result ($_[0]); - }; - } else { - my $errno = $!; - add $grp aio_unlink $dst, sub { - $! = $errno; - $grp->result (-1); - }; - } - }; - } else { - $grp->result (-1); - } - }, - - } else { - $grp->result (-1); - } - }; - } else { - $grp->result ($_[0]); - } - }; - - $grp -} - =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts @@ -396,6 +331,14 @@ Asynchronously unlink (delete) a file and call the callback with the result code. +=item aio_mknod $path, $mode, $dev, $callback->($status) + +Asynchronously create a device node (or fifo). See mknod(2). + +The only portable (POSIX) way of calling this function is: + + aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... + =item aio_link $srcpath, $dstpath, $callback->($status) Asynchronously create a new link to the existing object at C<$srcpath> at @@ -425,17 +368,119 @@ The callback a single argument which is either C or an array-ref with the filenames. +=item aio_copy $srcpath, $dstpath, $callback->($status) + +Try to copy the I (directories not supported as either source or +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 it creates the destination file with +mode 0200 and copies the contents of the source file into it using +C, followed by restoring atime, mtime, access mode and +uid/gid, in that order. + +If an error occurs, the partial destination file will be unlinked, if +possible, except when setting atime, mtime, access mode and uid/gid, where +errors are being ignored. + +=cut + +sub aio_copy($$;$) { + my ($src, $dst, $cb) = @_; + + my $pri = aioreq_pri; + my $grp = aio_group $cb; + + aioreq_pri $pri; + add $grp aio_open $src, O_RDONLY, 0, sub { + if (my $src_fh = $_[0]) { + my @stat = stat $src_fh; + + aioreq_pri $pri; + add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { + if (my $dst_fh = $_[0]) { + aioreq_pri $pri; + add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { + if ($_[0] == $stat[7]) { + $grp->result (0); + close $src_fh; + + # those should not normally block. should. should. + utime $stat[8], $stat[9], $dst; + chmod $stat[2] & 07777, $dst_fh; + chown $stat[4], $stat[5], $dst_fh; + close $dst_fh; + } else { + $grp->result (-1); + close $src_fh; + close $dst_fh; + + aioreq $pri; + add $grp aio_unlink $dst; + } + }; + } else { + $grp->result (-1); + } + }, + + } else { + $grp->result (-1); + } + }; + + $grp +} + +=item aio_move $srcpath, $dstpath, $callback->($status) + +Try to move the I (directories not supported as either source or +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, it copies the file with C and, if +that is successful, unlinking the C<$srcpath>. + +=cut + +sub aio_move($$;$) { + my ($src, $dst, $cb) = @_; + + my $pri = aioreq_pri; + my $grp = aio_group $cb; + + aioreq_pri $pri; + add $grp aio_rename $src, $dst, sub { + if ($_[0] && $! == EXDEV) { + aioreq_pri $pri; + add $grp aio_copy $src, $dst, sub { + $grp->result ($_[0]); + + if (!$_[0]) { + aioreq_pri $pri; + add $grp aio_unlink $src; + } + }; + } else { + $grp->result ($_[0]); + } + }; + + $grp +} + =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) Scans a directory (similar to C) but additionally tries to -separate the entries of directory C<$path> into two sets of names, ones -you can recurse into (directories or links to them), and ones you cannot -recurse into (everything else). +efficiently separate the entries of directory C<$path> into two sets of +names, directories you can recurse into (directories), and ones you cannot +recurse into (everything else, including symlinks to directories). C is a composite request that creates of many sub requests_ C<$maxreq> specifies the maximum number of outstanding aio requests that this function generates. If it is C<< <= 0 >>, then a suitable default -will be chosen (currently 6). +will be chosen (currently 4). On error, the callback is called without arguments, otherwise it receives two array-refs with path-relative entry names. @@ -482,22 +527,27 @@ sub aio_scandir($$$) { my ($path, $maxreq, $cb) = @_; + my $pri = aioreq_pri; + my $grp = aio_group $cb; - $maxreq = 6 if $maxreq <= 0; + $maxreq = 4 if $maxreq <= 0; # stat once + aioreq_pri $pri; add $grp aio_stat $path, sub { return $grp->result () if $_[0]; my $now = time; my $hash1 = join ":", (stat _)[0,1,3,7,9]; # read the directory entries + aioreq_pri $pri; add $grp aio_readdir $path, sub { my $entries = shift or return $grp->result (); # stat the dir another time + aioreq_pri $pri; add $grp aio_stat $path, sub { my $hash2 = join ":", (stat _)[0,1,3,7,9]; @@ -531,18 +581,20 @@ return unless @$entries; my $entry = pop @$entries; + aioreq_pri $pri; add $statgrp aio_stat "$path/$entry/.", sub { if ($_[0] < 0) { push @nondirs, $entry; } else { # need to check for real directory + aioreq_pri $pri; add $statgrp aio_lstat "$path/$entry", sub { if (-d _) { push @dirs, $entry; - if (!--$ndirs) { + unless (--$ndirs) { push @nondirs, @$entries; - $statgrp->cancel_subs; + feed $statgrp; } } else { push @nondirs, $entry; @@ -684,10 +736,6 @@ =item * You must not add requests to a group from within the group callback (or any later time). -=item * This does not harmonise well with C, so best do -not combine C with it. Groups and feeders are recommended for -this kind of concurrency-limiting. - =back Their lifetime, simplified, looks like this: when they are empty, they @@ -720,7 +768,21 @@ =item $grp->result (...) Set the result value(s) that will be passed to the group callback when all -subrequests have finished. By default, no argument will be passed. +subrequests have finished and set thre groups errno to the current value +of errno (just like calling C without an error number). By default, +no argument will be passed and errno is zero. + +=item $grp->errno ([$errno]) + +Sets the group errno value to C<$errno>, or the current value of errno +when the argument is missing. + +Every aio request has an associated errno value that is restored when +the callback is invoked. This method lets you change this value from its +default (0). + +Calling C will also set errno, so make sure you either set C<$!> +before the call to C, or call c after it. =item feed $grp $callback->($grp) @@ -786,6 +848,9 @@ regularly. Returns the number of events processed. Returns immediately when no events are outstanding. +If not all requests were processed for whatever reason, the filehandle +will still be ready when C returns. + Example: Install an Event watcher that automatically calls IO::AIO::poll_cb with high priority: @@ -793,6 +858,22 @@ poll => 'r', async => 1, cb => \&IO::AIO::poll_cb); +=item IO::AIO::poll_some $max_requests + +Similar to C, but only processes up to C<$max_requests> requests +at a time. + +Useful if you want to ensure some level of interactiveness when perl is +not fast enough to process all requests in time. + +Example: Install an Event watcher that automatically calls +IO::AIO::poll_some with low priority, to ensure that other parts of the +program get the CPU sometimes even under high AIO load. + + Event->io (fd => IO::AIO::poll_fileno, + poll => 'r', nice => 1, + cb => sub { IO::AIO::poll_some 256 }); + =item IO::AIO::poll_wait Wait till the result filehandle becomes ready for reading (simply does a @@ -803,14 +884,24 @@ =item IO::AIO::nreqs -Returns the number of requests currently outstanding (i.e. for which their -callback has not been invoked yet). +Returns the number of requests currently in the ready, execute or pending +states (i.e. for which their callback has not been invoked yet). Example: wait till there are no outstanding requests anymore: IO::AIO::poll_wait, IO::AIO::poll_cb while IO::AIO::nreqs; +=item IO::AIO::nready + +Returns the number of requests currently in the ready state (not yet +executed). + +=item IO::AIO::npending + +Returns the number of requests currently in the pending state (executed, +but not yet processed by poll_cb). + =item IO::AIO::flush Wait till all outstanding AIO requests have been handled. @@ -861,23 +952,23 @@ Under normal circumstances you don't need to call this function. -=item $oldnreqs = IO::AIO::max_outstanding $nreqs +=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs -[DEPRECATED] +This is a very bad function to use in interactive programs because it +blocks, and a bad way to reduce concurrency because it is inexact: Better +use an C together with a feed callback. Sets the maximum number of outstanding requests to C<$nreqs>. If you -try to queue up more than this number of requests, the caller will block until -some requests have been handled. - -The default is very large, so normally there is no practical limit. If you -queue up many requests in a loop it often improves speed if you set -this to a relatively low number, such as C<100>. - -This function does not work well together with C's, and their -feeder interface is better suited to limiting concurrency, so do not use -this function. - -Under normal circumstances you don't need to call this function. +to queue up more than this number of requests, the next call to the +C (and C and other functions calling C) +function will block until the limit is no longer exceeded. + +The default value is very large, so there is no practical limit on the +number of outstanding requests. + +You can still queue as many requests as you want. Therefore, +C is mainly useful in simple scripts (with low values) or +as a stop gap to shield against fatal memory overflow (with large values). =back @@ -902,8 +993,9 @@ min_parallel 8; END { - max_parallel 0; -} + min_parallel 1; + flush; +}; 1;