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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.147 by root, Wed Jun 3 12:24:49 2009 UTC vs.
Revision 1.164 by root, Tue Aug 18 03:26:02 2009 UTC

  # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
  use AnyEvent::AIO;
  # EV integration
- my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
+ my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
  # Event integration
  Event->io (fd => IO::AIO::poll_fileno,
             poll => 'r',
             cb => \&IO::AIO::poll_cb);
                              \&IO::AIO::poll_cb);
 =head1 DESCRIPTION
 This module implements asynchronous I/O using whatever means your
-operating system supports.
+operating system supports. It is implemented as an interface to C<libeio>
+(L<http://software.schmorp.de/pkg/libeio.html>).
 Asynchronous means that operations that can normally block your program
 (e.g. reading from disk) will be done asynchronously: the operation
 will still block, but you can do something else in the meantime. This
 is extremely useful for programs that need to stay interactive even
 on a RAID volume or over NFS when you do a number of stat operations
 concurrently.
 While most of this works on all types of file descriptors (for
 example sockets), using these functions on file descriptors that
-support nonblocking operation (again, sockets, pipes etc.) is very
+support nonblocking operation (again, sockets, pipes etc.) is
-inefficient. Use an event loop for that (such as the L<Event|Event>
+very inefficient. Use an event loop for that (such as the L<EV>
 module): IO::AIO will naturally fit into such an event loop itself.
 In this version, a number of threads are started that execute your
 requests and signal their completion. You don't need thread support
 in perl, and the threads created by this module will not be visible
 yourself, always call C<poll_cb> from within the same thread, or never
 call C<poll_cb> (or other C<aio_> functions) recursively.
 =head2 EXAMPLE
-This is a simple example that uses the Event module and loads
+This is a simple example that uses the EV module and loads
 F</etc/passwd> asynchronously:
    use Fcntl;
-   use Event;
+   use EV;
    use IO::AIO;
-   # register the IO::AIO callback with Event
+   # register the IO::AIO callback with EV
-   Event->io (fd => IO::AIO::poll_fileno,
+   my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
-              poll => 'r',
-              cb => \&IO::AIO::poll_cb);
    # queue the request to open /etc/passwd
    aio_open "/etc/passwd", O_RDONLY, 0, sub {
       my $fh = shift
          or die "error while opening: $!";
          # file contents now in $contents
          print $contents;
          # exit event loop and program
-         Event::unloop;
+         EV::unloop;
       };
    };
    # possibly queue up other requests, or open GUI windows,
    # check for sockets etc. etc.
    # process events as long as there are some:
-   Event::loop;
+   EV::loop;
 =head1 REQUEST ANATOMY AND LIFETIME
 Every C<aio_*> function creates a request. which is a C data structure not
 directly visible to Perl.
 package IO::AIO;
 use Carp ();
-no warnings;
+use common::sense;
-use strict 'vars';
 use base 'Exporter';
 BEGIN {
-   our $VERSION = '3.19';
+   our $VERSION = '3.3';
    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_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
                      aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
                      aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
                      aio_rename 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);
    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
                        nreqs nready npending nthreads
-                       max_poll_time max_poll_reqs);
+                       max_poll_time max_poll_reqs
+                       sendfile fadvise);
    push @AIO_REQ, qw(aio_busy); # not exported
    @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
 Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
 directory (i.e. opendir + readdir + closedir). The entries will not be
 sorted, and will B<NOT> include the C<.> and C<..> entries.
-The callback a single argument which is either C<undef> or an array-ref
+The callback is passed a single argument which is either C<undef> or an
-with the filenames.
+array-ref with the filenames.
+=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
+Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
+behaviour and output format. In case of an error, C<$entries> will be
+C<undef>.
+The flags are a combination of the following constants, ORed together (the
+flags will also be passed to the callback, possibly modified):
+=over 4
+=item IO::AIO::READDIR_DENTS
+When this flag is off, then the callback gets an arrayref with of names
+only (as with C<aio_readdir>), otherwise it gets an arrayref with
+C<[$name, $type, $inode]> arrayrefs, each describing a single directory
+entry in more detail.
+C<$name> is the name of the entry.
+C<$type> is one of the C<IO::AIO::DT_xxx> constants:
+C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
+C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
+C<IO::AIO::DT_WHT>.
+C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
+know, you have to run stat yourself. Also, for speed reasons, the C<$type>
+scalars are read-only: you can not modify them.
+C<$inode> is the inode number (which might not be exact on systems with 64
+bit inode numbers and 32 bit perls). This field has unspecified content on
+systems that do not deliver the inode information.
+=item IO::AIO::READDIR_DIRS_FIRST
+When this flag is set, then the names will be returned in an order where
+likely directories come first. This is useful when you need to quickly
+find directories, or you want to find all directories while avoiding to
+stat() each entry.
+If the system returns type information in readdir, then this is used
+to find directories directly.  Otherwise, likely directories are files
+beginning with ".", or otherwise files with no dots, of which files with
+short names are tried first.
+=item IO::AIO::READDIR_STAT_ORDER
+When this flag is set, then the names will be returned in an order
+suitable for stat()'ing each one. That is, when you plan to stat()
+all files in the given directory, then the returned order will likely
+be fastest.
+If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
+the likely dirs come first, resulting in a less optimal stat order.
+=item IO::AIO::READDIR_FOUND_UNKNOWN
+This flag should not be set when calling C<aio_readdirx>. Instead, it
+is being set by C<aio_readdirx>, when any of the C<$type>'s found were
+C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
+C<$type>'s are known, which can be used to speed up some algorithms.
+=back
 =item aio_load $path, $data, $callback->($status)
 This is a composite request that tries to fully load the given file into
 =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
-the C<0> (error) or C<-1> ok.
+a status of C<0> (error) or C<-1> (ok).
 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.
 =item aio_move $srcpath, $dstpath, $callback->($status)
 Try to move the I<file> (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.
+the status C<0> (error) or C<-1> (ok).
 This is a composite request that tries to rename(2) the file first; if
 rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
 that is successful, unlinks the C<$srcpath>.
 Implementation notes.
 The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
+If readdir returns file type information, then this is used directly to
+find directories.
-After reading the directory, the modification time, size etc. of the
+Otherwise, after reading the directory, the modification time, size etc.
-directory before and after the readdir is checked, and if they match (and
+of the directory before and after the readdir is checked, and if they
-isn't the current time), the link count will be used to decide how many
+match (and isn't the current time), the link count will be used to decide
-entries are directories (if >= 2). Otherwise, no knowledge of the number
+how many entries are directories (if >= 2). Otherwise, no knowledge of the
-of subdirectories will be assumed.
+number of subdirectories will be assumed.
-Then entries will be sorted into likely directories (everything without
+Then entries will be sorted into likely directories a non-initial dot
-a non-initial dot currently) and likely non-directories (everything
+currently) and likely non-directories (see C<aio_readdirx>). Then every
-else). Then every entry plus an appended C</.> will be C<stat>'ed,
+entry plus an appended C</.> will be C<stat>'ed, likely directories first,
-likely directories first. If that succeeds, it assumes that the entry
+in order of their inode numbers. If that succeeds, it assumes that the
-is a directory or a symlink to directory (which will be checked
+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
 filesystems might detect the type of the entry without reading the inode
-data (e.g. ext2fs filetype feature).
+data (e.g. ext2fs filetype feature), even on systems that cannot return
+the filetype information on readdir.
 If the known number of directories (link count - 2) has been reached, the
 rest of the entries is assumed to be non-directories.
 This only works with certainty on POSIX (= UNIX) filesystems, which
       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 {
+      add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
          my $entries = shift
             or return $grp->result ();
          # stat the dir another time
          aioreq_pri $pri;
             # take the slow route if anything looks fishy
             if ($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
+               # for non-posix-fs's, we rely on nlink < 2
                $ndirs = (stat _)[3] - 2
                   or return $grp->result ([], $entries);
             }
-            # sort into likely dirs and likely nondirs
-            # dirs == files without ".", short entries first
-            $entries = [map $_->[0],
-                           sort { $b->[1] cmp $a->[1] }
-                              map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
-                                 @$entries];
             my (@dirs, @nondirs);
             my $statgrp = add $grp aio_group sub {
                $grp->result (\@dirs, \@nondirs);
             };
             limit $statgrp $maxreq;
             feed $statgrp sub {
                return unless @$entries;
-               my $entry = pop @$entries;
+               my $entry = shift @$entries;
                aioreq_pri $pri;
                add $statgrp aio_stat "$path/$entry/.", sub {
                   if ($_[0] < 0) {
                      push @nondirs, $entry;
 (E.g. rename). This might not work on all operating systems or have any
 specific effect, but usually it makes sure that directory changes get
 written to disc. It works for anything that can be opened for read-only,
 not just directories.
+Future versions of this function might fall back to other methods when
+C<fsync> on the directory fails (such as calling C<sync>).
 Passes C<0> when everything went ok, and C<-1> on error.
 =cut
 sub aio_pathsync($;$) {
 =item cancel $req
 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
+untouched (with the exception of readdir). That means that requests that
-stopped and resources held by the request will not be freed prematurely.
+currently execute will not be stopped and resources held by the request
+will not be freed prematurely.
 =item cb $req $callback->(...)
 Replace (or simply set) the callback registered to the request.
 =over 4
 =item $fileno = IO::AIO::poll_fileno
 Return the I<request result pipe file descriptor>. This filehandle must be
-polled for reading by some mechanism outside this module (e.g. Event or
+polled for reading by some mechanism outside this module (e.g. EV, Glib,
-select, see below or the SYNOPSIS). If the pipe becomes readable you have
+select and so on, see below or the SYNOPSIS). If the pipe becomes readable
-to call C<poll_cb> to check the results.
+you have to call C<poll_cb> to check the results.
 See C<poll_cb> for an example.
 =item IO::AIO::poll_cb
 If not all requests were processed for whatever reason, the filehandle
 will still be ready when C<poll_cb> returns, so normally you don't have to
 do anything special to have it called later.
 Example: Install an Event watcher that automatically calls
-IO::AIO::poll_cb with high priority:
+IO::AIO::poll_cb with high priority (more examples can be found in the
+SYNOPSIS section, at the top of this document):
    Event->io (fd => IO::AIO::poll_fileno,
               poll => 'r', async => 1,
               cb => \&IO::AIO::poll_cb);
 =item IO::AIO::npending
 Returns the number of requests currently in the pending state (executed,
 but not yet processed by poll_cb).
+=back
+=head3 MISCELLANEOUS FUNCTIONS
+IO::AIO implements some functions that might be useful, but are not
+asynchronous.
+=over 4
+=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
+likely cached already and the output filehandle is set to non-blocking
+operations).
+Returns the number of bytes copied, or C<-1> on error.
+=item IO::AIO::fadvise $fh, $offset, $len, $advice
+Simply calls the C<posix_fadvise> function (see it's
+manpage for details). The following advice constants are
+avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
+C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
+C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
+On systems that do not implement C<posix_fadvise>, this function returns
+ENOSYS, otherwise the return value of C<posix_fadvise>.
 =back
 =cut

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.147 by root, Wed Jun 3 12:24:49 2009 UTC vs. Revision 1.164 by root, Tue Aug 18 03:26:02 2009 UTC

Diff Legend

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.147 by root, Wed Jun 3 12:24:49 2009 UTC vs.
Revision 1.164 by root, Tue Aug 18 03:26:02 2009 UTC