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Revision 1.149 by root, Sat Jun 6 18:19:35 2009 UTC vs.
Revision 1.156 by root, Tue Jun 16 23:41:59 2009 UTC

30 30
31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) 31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32 use AnyEvent::AIO; 32 use AnyEvent::AIO;
33 33
34 # EV integration 34 # EV integration
35 my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 35 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
36 36
37 # Event integration 37 # Event integration
38 Event->io (fd => IO::AIO::poll_fileno, 38 Event->io (fd => IO::AIO::poll_fileno,
39 poll => 'r', 39 poll => 'r',
40 cb => \&IO::AIO::poll_cb); 40 cb => \&IO::AIO::poll_cb);
52 \&IO::AIO::poll_cb); 52 \&IO::AIO::poll_cb);
53 53
54=head1 DESCRIPTION 54=head1 DESCRIPTION
55 55
56This module implements asynchronous I/O using whatever means your 56This module implements asynchronous I/O using whatever means your
57operating system supports. 57operating system supports. It is implemented as an interface to C<libeio>
58(L<http://software.schmorp.de/pkg/libeio.html>).
58 59
59Asynchronous means that operations that can normally block your program 60Asynchronous means that operations that can normally block your program
60(e.g. reading from disk) will be done asynchronously: the operation 61(e.g. reading from disk) will be done asynchronously: the operation
61will still block, but you can do something else in the meantime. This 62will still block, but you can do something else in the meantime. This
62is extremely useful for programs that need to stay interactive even 63is extremely useful for programs that need to stay interactive even
66on a RAID volume or over NFS when you do a number of stat operations 67on a RAID volume or over NFS when you do a number of stat operations
67concurrently. 68concurrently.
68 69
69While most of this works on all types of file descriptors (for 70While most of this works on all types of file descriptors (for
70example sockets), using these functions on file descriptors that 71example sockets), using these functions on file descriptors that
71support nonblocking operation (again, sockets, pipes etc.) is very 72support nonblocking operation (again, sockets, pipes etc.) is
72inefficient. Use an event loop for that (such as the L<Event|Event> 73very inefficient. Use an event loop for that (such as the L<EV>
73module): IO::AIO will naturally fit into such an event loop itself. 74module): IO::AIO will naturally fit into such an event loop itself.
74 75
75In this version, a number of threads are started that execute your 76In this version, a number of threads are started that execute your
76requests and signal their completion. You don't need thread support 77requests and signal their completion. You don't need thread support
77in perl, and the threads created by this module will not be visible 78in perl, and the threads created by this module will not be visible
87yourself, always call C<poll_cb> from within the same thread, or never 88yourself, always call C<poll_cb> from within the same thread, or never
88call C<poll_cb> (or other C<aio_> functions) recursively. 89call C<poll_cb> (or other C<aio_> functions) recursively.
89 90
90=head2 EXAMPLE 91=head2 EXAMPLE
91 92
92This is a simple example that uses the Event module and loads 93This is a simple example that uses the EV module and loads
93F</etc/passwd> asynchronously: 94F</etc/passwd> asynchronously:
94 95
95 use Fcntl; 96 use Fcntl;
96 use Event; 97 use EV;
97 use IO::AIO; 98 use IO::AIO;
98 99
99 # register the IO::AIO callback with Event 100 # register the IO::AIO callback with EV
100 Event->io (fd => IO::AIO::poll_fileno, 101 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
101 poll => 'r',
102 cb => \&IO::AIO::poll_cb);
103 102
104 # queue the request to open /etc/passwd 103 # queue the request to open /etc/passwd
105 aio_open "/etc/passwd", O_RDONLY, 0, sub { 104 aio_open "/etc/passwd", O_RDONLY, 0, sub {
106 my $fh = shift 105 my $fh = shift
107 or die "error while opening: $!"; 106 or die "error while opening: $!";
119 118
120 # file contents now in $contents 119 # file contents now in $contents
121 print $contents; 120 print $contents;
122 121
123 # exit event loop and program 122 # exit event loop and program
124 Event::unloop; 123 EV::unloop;
125 }; 124 };
126 }; 125 };
127 126
128 # possibly queue up other requests, or open GUI windows, 127 # possibly queue up other requests, or open GUI windows,
129 # check for sockets etc. etc. 128 # check for sockets etc. etc.
130 129
131 # process events as long as there are some: 130 # process events as long as there are some:
132 Event::loop; 131 EV::loop;
133 132
134=head1 REQUEST ANATOMY AND LIFETIME 133=head1 REQUEST ANATOMY AND LIFETIME
135 134
136Every C<aio_*> function creates a request. which is a C data structure not 135Every C<aio_*> function creates a request. which is a C data structure not
137directly visible to Perl. 136directly visible to Perl.
193use strict 'vars'; 192use strict 'vars';
194 193
195use base 'Exporter'; 194use base 'Exporter';
196 195
197BEGIN { 196BEGIN {
198 our $VERSION = '3.2'; 197 our $VERSION = '3.23';
199 198
200 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close 199 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
201 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx 200 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
202 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync 201 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
203 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead 202 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
548The flags are a combination of the following constants, ORed together (the 547The flags are a combination of the following constants, ORed together (the
549flags will also be passed to the callback, possibly modified): 548flags will also be passed to the callback, possibly modified):
550 549
551=over 4 550=over 4
552 551
553=item AIO::READDIR_DENTS 552=item IO::AIO::READDIR_DENTS
554 553
555When this flag is off, then the callback gets an arrayref with of names 554When this flag is off, then the callback gets an arrayref with of names
556only (as with C<aio_readdir>), otherwise it gets an arrayref with 555only (as with C<aio_readdir>), otherwise it gets an arrayref with
557C<[$name, $inode, $type]> arrayrefs, each describing a single directory 556C<[$name, $type, $inode]> arrayrefs, each describing a single directory
558entry in more detail. 557entry in more detail.
559 558
560C<$name> is the name of the entry. 559C<$name> is the name of the entry.
561 560
562C<$inode> is the inode number (which might not be exact on systems with 64
563bit inode numbers and 32 bit perls). On systems that do not deliver the
564inode information, this will always be zero.
565
566C<$type> is one of the C<AIO::DT_xxx> constants: 561C<$type> is one of the C<IO::AIO::DT_xxx> constants:
567 562
568C<AIO::DT_UNKNOWN>, C<AIO::DT_FIFO>, C<AIO::DT_CHR>, C<AIO::DT_DIR>, 563C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
569C<AIO::DT_BLK>, C<AIO::DT_REG>, C<AIO::DT_LNK>, C<AIO::DT_SOCK>, 564C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
570C<AIO::DT_WHT>. 565C<IO::AIO::DT_WHT>.
571 566
572C<AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 567C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
573know, you have to run stat yourself. Also, for speed reasons, the C<$type> 568know, you have to run stat yourself. Also, for speed reasons, the C<$type>
574scalars are read-only: you can not modify them. 569scalars are read-only: you can not modify them.
575 570
571C<$inode> is the inode number (which might not be exact on systems with 64
572bit inode numbers and 32 bit perls). This field has unspecified content on
573systems that do not deliver the inode information.
574
576=item AIO::READDIR_DIRS_FIRST 575=item IO::AIO::READDIR_DIRS_FIRST
577 576
578When this flag is set, then the names will be returned in an order where 577When this flag is set, then the names will be returned in an order where
579likely directories come first. This is useful when you need to quickly 578likely directories come first. This is useful when you need to quickly
580find directories, or you want to find all directories while avoiding to 579find directories, or you want to find all directories while avoiding to
581stat() each entry. 580stat() each entry.
583If the system returns type information in readdir, then this is used 582If the system returns type information in readdir, then this is used
584to find directories directly. Otherwise, likely directories are files 583to find directories directly. Otherwise, likely directories are files
585beginning with ".", or otherwise files with no dots, of which files with 584beginning with ".", or otherwise files with no dots, of which files with
586short names are tried first. 585short names are tried first.
587 586
588=item AIO::READDIR_STAT_ORDER 587=item IO::AIO::READDIR_STAT_ORDER
589 588
590When this flag is set, then the names will be returned in an order 589When this flag is set, then the names will be returned in an order
591suitable for stat()'ing each one. That is, when you plan to stat() 590suitable for stat()'ing each one. That is, when you plan to stat()
592all files in the given directory, then the returned order will likely 591all files in the given directory, then the returned order will likely
593be fastest. 592be fastest.
594 593
595If both this flag and IO::READDIR_DIRS_FIRST are specified, then the 594If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
596likely dirs come first, resulting in a less optimal stat order. 595the likely dirs come first, resulting in a less optimal stat order.
597 596
598=item AIO::READDIR_FOUND_UNKNOWN 597=item IO::AIO::READDIR_FOUND_UNKNOWN
599 598
600This flag should not be set when calling C<aio_readdirx>. Instead, it 599This flag should not be set when calling C<aio_readdirx>. Instead, it
601is being set by C<aio_readdirx>, when any of the C<$type>'s found were 600is being set by C<aio_readdirx>, when any of the C<$type>'s found were
602C<AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all 601C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
603C<$type>'s are known, which can be used to speed up some algorithms. 602C<$type>'s are known, which can be used to speed up some algorithms.
604 603
605=back 604=back
606 605
607 606
840 # take the slow route if anything looks fishy 839 # take the slow route if anything looks fishy
841 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 840 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
842 $ndirs = -1; 841 $ndirs = -1;
843 } else { 842 } else {
844 # if nlink == 2, we are finished 843 # if nlink == 2, we are finished
845 # on non-posix-fs's, we rely on nlink < 2 844 # for non-posix-fs's, we rely on nlink < 2
846 $ndirs = (stat _)[3] - 2 845 $ndirs = (stat _)[3] - 2
847 or return $grp->result ([], $entries); 846 or return $grp->result ([], $entries);
848 } 847 }
849 848
850 my (@dirs, @nondirs); 849 my (@dirs, @nondirs);
854 }; 853 };
855 854
856 limit $statgrp $maxreq; 855 limit $statgrp $maxreq;
857 feed $statgrp sub { 856 feed $statgrp sub {
858 return unless @$entries; 857 return unless @$entries;
859 my $entry = pop @$entries; 858 my $entry = shift @$entries;
860 859
861 aioreq_pri $pri; 860 aioreq_pri $pri;
862 add $statgrp aio_stat "$path/$entry/.", sub { 861 add $statgrp aio_stat "$path/$entry/.", sub {
863 if ($_[0] < 0) { 862 if ($_[0] < 0) {
864 push @nondirs, $entry; 863 push @nondirs, $entry;
1045=item cancel $req 1044=item cancel $req
1046 1045
1047Cancels the request, if possible. Has the effect of skipping execution 1046Cancels the request, if possible. Has the effect of skipping execution
1048when entering the B<execute> state and skipping calling the callback when 1047when entering the B<execute> state and skipping calling the callback when
1049entering the the B<result> state, but will leave the request otherwise 1048entering the the B<result> state, but will leave the request otherwise
1050untouched. That means that requests that currently execute will not be 1049untouched (with the exception of readdir). That means that requests that
1051stopped and resources held by the request will not be freed prematurely. 1050currently execute will not be stopped and resources held by the request
1051will not be freed prematurely.
1052 1052
1053=item cb $req $callback->(...) 1053=item cb $req $callback->(...)
1054 1054
1055Replace (or simply set) the callback registered to the request. 1055Replace (or simply set) the callback registered to the request.
1056 1056
1207=over 4 1207=over 4
1208 1208
1209=item $fileno = IO::AIO::poll_fileno 1209=item $fileno = IO::AIO::poll_fileno
1210 1210
1211Return the I<request result pipe file descriptor>. This filehandle must be 1211Return the I<request result pipe file descriptor>. This filehandle must be
1212polled for reading by some mechanism outside this module (e.g. Event or 1212polled for reading by some mechanism outside this module (e.g. EV, Glib,
1213select, see below or the SYNOPSIS). If the pipe becomes readable you have 1213select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1214to call C<poll_cb> to check the results. 1214you have to call C<poll_cb> to check the results.
1215 1215
1216See C<poll_cb> for an example. 1216See C<poll_cb> for an example.
1217 1217
1218=item IO::AIO::poll_cb 1218=item IO::AIO::poll_cb
1219 1219
1226If not all requests were processed for whatever reason, the filehandle 1226If not all requests were processed for whatever reason, the filehandle
1227will still be ready when C<poll_cb> returns, so normally you don't have to 1227will still be ready when C<poll_cb> returns, so normally you don't have to
1228do anything special to have it called later. 1228do anything special to have it called later.
1229 1229
1230Example: Install an Event watcher that automatically calls 1230Example: Install an Event watcher that automatically calls
1231IO::AIO::poll_cb with high priority: 1231IO::AIO::poll_cb with high priority (more examples can be found in the
1232SYNOPSIS section, at the top of this document):
1232 1233
1233 Event->io (fd => IO::AIO::poll_fileno, 1234 Event->io (fd => IO::AIO::poll_fileno,
1234 poll => 'r', async => 1, 1235 poll => 'r', async => 1,
1235 cb => \&IO::AIO::poll_cb); 1236 cb => \&IO::AIO::poll_cb);
1236 1237

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