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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.86 by root, Sat Oct 28 23:32:29 2006 UTC vs.
Revision 1.116 by root, Wed Oct 3 21:27:51 2007 UTC

 =head1 SYNOPSIS
  use IO::AIO;
  aio_open "/etc/passwd", O_RDONLY, 0, sub {
-    my ($fh) = @_;
+    my $fh = shift
+       or die "/etc/passwd: $!";
     ...
  };
  aio_unlink "/tmp/file", sub { };
 etc.), but can also be used to easily do operations in parallel that are
 normally done sequentially, e.g. stat'ing many files, which is much faster
 on a RAID volume or over NFS when you do a number of stat operations
 concurrently.
-While this works on all types of file descriptors (for example sockets),
+While most of this works on all types of file descriptors (for
-using these functions on file descriptors that support nonblocking
+example sockets), using these functions on file descriptors that
-operation (again, sockets, pipes etc.) is very inefficient. Use an event
+support nonblocking operation (again, sockets, pipes etc.) is very
-loop for that (such as the L<Event|Event> module): IO::AIO will naturally
+inefficient. Use an event loop for that (such as the L<Event|Event>
-fit into such an event loop itself.
+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
 to perl. In the future, this module might make use of the native 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.
-Although the module will work with in the presence of other (Perl-)
+Although the module will work in the presence of other (Perl-) threads,
-threads, it is currently not reentrant in any way, so use appropriate
+it is currently not reentrant in any way, so use appropriate locking
-locking yourself, always call C<poll_cb> from within the same thread, or
+yourself, always call C<poll_cb> from within the same thread, or never
-never call C<poll_cb> (or other C<aio_> functions) recursively.
+call C<poll_cb> (or other C<aio_> functions) recursively.
 =head2 EXAMPLE
 This is a simple example that uses the Event module and loads
 F</etc/passwd> asynchronously:
               poll => 'r',
               cb => \&IO::AIO::poll_cb);
    # queue the request to open /etc/passwd
    aio_open "/etc/passwd", O_RDONLY, 0, sub {
-      my $fh = $_[0]
+      my $fh = shift
          or die "error while opening: $!";
       # stat'ing filehandles is generally non-blocking
       my $size = -s $fh;
 Request has reached the end of its lifetime and holds no resources anymore
 (except possibly for the Perl object, but its connection to the actual
 aio request is severed and calling its methods will either do nothing or
 result in a runtime error).
+=back
 =cut
 package IO::AIO;
 no warnings;
 use strict 'vars';
 use base 'Exporter';
 BEGIN {
-   our $VERSION = '2.1';
+   our $VERSION = '2.5';
    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_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link
-                     aio_copy aio_group aio_nop aio_mknod);
+                     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 = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
    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);
    XSLoader::load ("IO::AIO", $VERSION);
 }
 =head1 FUNCTIONS
-=head2 AIO FUNCTIONS
+=head2 AIO REQUEST FUNCTIONS
 All the C<aio_*> calls are more or less thin wrappers around the syscall
 with the same name (sans C<aio_>). The arguments are similar or identical,
 and they all accept an additional (and optional) C<$callback> argument
 which must be a code reference. This code reference will get called with
 syscall has been executed asynchronously.
 All functions expecting a filehandle keep a copy of the filehandle
 internally until the request has finished.
-All requests return objects of type L<IO::AIO::REQ> that allow further
+All functions return request objects of type L<IO::AIO::REQ> that allow
-manipulation of those requests while they are in-flight.
+further manipulation of those requests while they are in-flight.
 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
+encoded as octets. 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.
+current working directory anywhere in the program and then use relative
+paths.
-To encode pathnames to byte form, either make sure you either: a)
+To encode pathnames as octets, either make sure you either: a) always pass
-always pass in filenames you got from outside (command line, readdir
+in filenames you got from outside (command line, readdir etc.) without
-etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode
+tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
 your pathnames to the locale (or other) encoding in effect in the user
 environment, d) use Glib::filename_from_unicode on unicode filenames or e)
-use something else.
+use something else to ensure your scalar has the correct contents.
+This works, btw. independent of the internal UTF-8 bit, which IO::AIO
+handles correctly wether it is set or not.
 =over 4
 =item $prev_pri = aioreq_pri [$pri]
       aio_read $_[0], ..., sub {
          ...
       };
    };
 =item aioreq_nice $pri_adjust
 Similar to C<aioreq_pri>, but subtracts the given value from the current
-priority, so effects are cumulative.
+priority, so the effect is cumulative.
 =item aio_open $pathname, $flags, $mode, $callback->($fh)
 Asynchronously open or create a file and call the callback with a newly
 created filehandle for the file.
 list. They are the same as used by C<sysopen>.
 Likewise, C<$mode> specifies the mode of the newly created file, if it
 didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
 except that it is mandatory (i.e. use C<0> if you don't create new files,
-and C<0666> or C<0777> if you do).
+and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
+by the umask in effect then the request is being executed, so better never
+change the umask.
 Example:
    aio_open "/etc/passwd", O_RDONLY, 0, sub {
       if ($_[0]) {
       } else {
          die "open failed: $!\n";
       }
    };
 =item aio_close $fh, $callback->($status)
 Asynchronously close a file and call the callback with the result
-code. I<WARNING:> although accepted, you should not pass in a perl
+code.
-filehandle here, as perl will likely close the file descriptor another
-time when the filehandle is destroyed. Normally, you can safely call perls
-C<close> or just let filehandles go out of scope.
-This is supposed to be a bug in the API, so that might change. It's
+Unlike the other functions operating on files, this function uses the
-therefore best to avoid this function.
+PerlIO layer to close the filehandle. The reason is that the PerlIO API
+insists on closing the underlying fd itself, no matter what, and doesn't
+allow modifications to the fd. Unfortunately, it is not clear that you can
+call PerlIO from different threads (actually, its quite clear that this
+won't work in some cases), so while it likely works perfectly with simple
+file handles (such as the ones created by C<aio_open>) it might fail in
+interesting ways for others.
+Having said that, aio_close tries to clean up the filehandle as much as
+possible before handing it to an io thread, and generally does work.
 =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 the specified C<fh> and C<offset>
+Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>
-into the scalar given by C<data> and offset C<dataoffset> and calls the
+into the scalar given by C<$data> and offset C<$dataoffset> and calls the
 callback without the actual number of bytes read (or -1 on error, just
 like the syscall).
+If C<$offset> is undefined, then the current file descriptor offset will
+be used (and updated), otherwise the file descriptor offset will not be
+changed by these calls.
+If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.
+If C<$dataoffset> is less than zero, it will be counted from the end of
+C<$data>.
 The C<$data> scalar I<MUST NOT> be modified in any way while the request
-is outstanding. Modifying it can result in segfaults or WW3 (if the
+is outstanding. Modifying it can result in segfaults or World War III (if
-necessary/optional hardware is installed).
+the necessary/optional hardware is installed).
 Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
 offset C<0> within the scalar:
    aio_read $fh, 7, 15, $buffer, 0, sub {
       $_[0] > 0 or die "read error: $!";
       print "read $_[0] bytes: <$buffer>\n";
    };
 =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
 Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
 reading at byte offset C<$in_offset>, and starts writing at the current
 C<$in_fh> than are written, and there is no way to find out how many
 bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
 provides the number of bytes written to C<$out_fh>. Only if the result
 value equals C<$length> one can assume that C<$length> bytes have been
 read.
 =item aio_readahead $fh,$offset,$length, $callback->($retval)
 C<aio_readahead> populates the page cache with data from a file so that
 subsequent reads from that file will not block on disk I/O. The C<$offset>
 file. The current file offset of the file is left unchanged.
 If that syscall doesn't exist (likely if your OS isn't Linux) it will be
 emulated by simply reading the data, which would have a similar effect.
 =item aio_stat  $fh_or_path, $callback->($status)
 =item aio_lstat $fh, $callback->($status)
 Works like perl's C<stat> or C<lstat> in void context. The callback will
    aio_stat "/etc/passwd", sub {
       $_[0] and die "stat failed: $!";
       print "size is ", -s _, "\n";
    };
+=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
+Works like perl's C<utime> function (including the special case of $atime
+and $mtime being undef). Fractional times are supported if the underlying
+syscalls support them.
+When called with a pathname, uses utimes(2) if available, otherwise
+utime(2). If called on a file descriptor, uses futimes(2) if available,
+otherwise returns ENOSYS, so this is not portable.
+Examples:
+   # set atime and mtime to current time (basically touch(1)):
+   aio_utime "path", undef, undef;
+   # set atime to current time and mtime to beginning of the epoch:
+   aio_utime "path", time, undef; # undef==0
+=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
+Works like perl's C<chown> function, except that C<undef> for either $uid
+or $gid is being interpreted as "do not change" (but -1 can also be used).
+Examples:
+   # same as "chown root path" in the shell:
+   aio_chown "path", 0, -1;
+   # same as above:
+   aio_chown "path", 0, undef;
+=item aio_truncate $fh_or_path, $offset, $callback->($status)
+Works like truncate(2) or ftruncate(2).
+=item aio_chmod $fh_or_path, $mode, $callback->($status)
+Works like perl's C<chmod> function.
 =item aio_unlink $pathname, $callback->($status)
 Asynchronously unlink (delete) a file and call the callback with the
 result code.
 =item aio_mknod $path, $mode, $dev, $callback->($status)
 [EXPERIMENTAL]
 Asynchronously create a device node (or fifo). See mknod(2).
 The only (POSIX-) portable 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<$srcpath> at
 the path C<$dstpath> and call the callback with the result code.
 =item aio_symlink $srcpath, $dstpath, $callback->($status)
 Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
 the path C<$dstpath> and call the callback with the result code.
+=item aio_readlink $path, $callback->($link)
+Asynchronously read the symlink specified by C<$path> and pass it to
+the callback. If an error occurs, nothing or undef gets passed to the
+callback.
 =item aio_rename $srcpath, $dstpath, $callback->($status)
 Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
 rename(2) and call the callback with the result code.
+=item aio_mkdir $pathname, $mode, $callback->($status)
+Asynchronously mkdir (create) a directory and call the callback with
+the result code. C<$mode> will be modified by the umask at the time the
+request is executed, so do not change your umask.
 =item aio_rmdir $pathname, $callback->($status)
 Asynchronously rmdir (delete) a directory and call the callback with the
 result code.
 =item aio_readdir $pathname, $callback->($entries)
 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
 with the filenames.
+=item aio_load $path, $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.
+=cut
+sub aio_load($$;$) {
+   aio_block {
+      my ($path, undef, $cb) = @_;
+      my $data = \$_[1];
+      my $pri = aioreq_pri;
+      my $grp = aio_group $cb;
+      aioreq_pri $pri;
+      add $grp aio_open $path, O_RDONLY, 0, sub {
+         my $fh = shift
+            or return $grp->result (-1);
+         aioreq_pri $pri;
+         add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
+            $grp->result ($_[0]);
+         };
+      };
+      $grp
+   }
+}
 =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
 errors are being ignored.
 =cut
 sub aio_copy($$;$) {
+   aio_block {
-   my ($src, $dst, $cb) = @_;
+      my ($src, $dst, $cb) = @_;
-   my $pri = aioreq_pri;
+      my $pri = aioreq_pri;
-   my $grp = aio_group $cb;
+      my $grp = aio_group $cb;
-   aioreq_pri $pri;
+      aioreq_pri $pri;
-   add $grp aio_open $src, O_RDONLY, 0, sub {
+      add $grp aio_open $src, O_RDONLY, 0, sub {
-      if (my $src_fh = $_[0]) {
+         if (my $src_fh = $_[0]) {
-         my @stat = stat $src_fh;
+            my @stat = stat $src_fh;
-         aioreq_pri $pri;
+            aioreq_pri $pri;
-         add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
+            add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
-            if (my $dst_fh = $_[0]) {
+               if (my $dst_fh = $_[0]) {
-               aioreq_pri $pri;
+                  aioreq_pri $pri;
-               add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
+                  add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
-                  if ($_[0] == $stat[7]) {
+                     if ($_[0] == $stat[7]) {
-                     $grp->result (0);
+                        $grp->result (0);
-                     close $src_fh;
+                        close $src_fh;
-                     # those should not normally block. should. should.
+                        # those should not normally block. should. should.
-                     utime $stat[8], $stat[9], $dst;
+                        utime $stat[8], $stat[9], $dst;
-                     chmod $stat[2] & 07777, $dst_fh;
+                        chmod $stat[2] & 07777, $dst_fh;
-                     chown $stat[4], $stat[5], $dst_fh;
+                        chown $stat[4], $stat[5], $dst_fh;
-                     close $dst_fh;
+                        close $dst_fh;
-                  } else {
+                     } else {
-                     $grp->result (-1);
+                        $grp->result (-1);
-                     close $src_fh;
+                        close $src_fh;
-                     close $dst_fh;
+                        close $dst_fh;
-                     aioreq $pri;
+                        aioreq $pri;
-                     add $grp aio_unlink $dst;
+                        add $grp aio_unlink $dst;
+                     }
-                  }
+                  };
+               } else {
+                  $grp->result (-1);
-               };
+               }
-            } else {
-               $grp->result (-1);
-            }
+            },
+         } else {
+            $grp->result (-1);
-         },
+         }
-      } else {
-         $grp->result (-1);
-      }
+      };
+      $grp
-   };
+   }
-   $grp
 }
 =item aio_move $srcpath, $dstpath, $callback->($status)
 Try to move the I<file> (directories not supported as either source or
 that is successful, unlinking the C<$srcpath>.
 =cut
 sub aio_move($$;$) {
+   aio_block {
-   my ($src, $dst, $cb) = @_;
+      my ($src, $dst, $cb) = @_;
-   my $pri = aioreq_pri;
+      my $pri = aioreq_pri;
-   my $grp = aio_group $cb;
+      my $grp = aio_group $cb;
-   aioreq_pri $pri;
+      aioreq_pri $pri;
-   add $grp aio_rename $src, $dst, sub {
+      add $grp aio_rename $src, $dst, sub {
-      if ($_[0] && $! == EXDEV) {
+         if ($_[0] && $! == EXDEV) {
-         aioreq_pri $pri;
+            aioreq_pri $pri;
-         add $grp aio_copy $src, $dst, sub {
+            add $grp aio_copy $src, $dst, sub {
+               $grp->result ($_[0]);
+               if (!$_[0]) {
+                  aioreq_pri $pri;
+                  add $grp aio_unlink $src;
+               }
+            };
+         } else {
             $grp->result ($_[0]);
-            if (!$_[0]) {
-               aioreq_pri $pri;
-               add $grp aio_unlink $src;
-            }
-         };
+         }
-      } else {
-         $grp->result ($_[0]);
-      }
+      };
+      $grp
-   };
+   }
-   $grp
 }
 =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
 Scans a directory (similar to C<aio_readdir>) but additionally tries to
 as those tend to return 0 or 1 as link counts, which disables the
 directory counting heuristic.
 =cut
-sub aio_scandir($$$) {
+sub aio_scandir($$;$) {
+   aio_block {
-   my ($path, $maxreq, $cb) = @_;
+      my ($path, $maxreq, $cb) = @_;
-   my $pri = aioreq_pri;
+      my $pri = aioreq_pri;
-   my $grp = aio_group $cb;
+      my $grp = aio_group $cb;
-   $maxreq = 4 if $maxreq <= 0;
+      $maxreq = 4 if $maxreq <= 0;
-   # stat once
+      # 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 {
+      add $grp aio_stat $path, sub {
-         my $entries = shift
-            or return $grp->result ();
+         return $grp->result () if $_[0];
+         my $now = time;
+         my $hash1 = join ":", (stat _)[0,1,3,7,9];
-         # stat the dir another time
+         # 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 {
+            add $grp aio_stat $path, sub {
-            my $hash2 = join ":", (stat _)[0,1,3,7,9];
+               my $hash2 = join ":", (stat _)[0,1,3,7,9];
-            my $ndirs;
+               my $ndirs;
-            # take the slow route if anything looks fishy
+               # take the slow route if anything looks fishy
-            if ($hash1 ne $hash2 or (stat _)[9] == $now) {
+               if ($hash1 ne $hash2 or (stat _)[9] == $now) {
-               $ndirs = -1;
+                  $ndirs = -1;
-            } else {
+               } else {
-               # if nlink == 2, we are finished
+                  # if nlink == 2, we are finished
-               # on non-posix-fs's, we rely on nlink < 2
+                  # on non-posix-fs's, we rely on nlink < 2
-               $ndirs = (stat _)[3] - 2
+                  $ndirs = (stat _)[3] - 2
-                  or return $grp->result ([], $entries);
+                     or return $grp->result ([], $entries);
-            }
+               }
-            # sort into likely dirs and likely nondirs
+               # sort into likely dirs and likely nondirs
-            # dirs == files without ".", short entries first
+               # dirs == files without ".", short entries first
-            $entries = [map $_->[0],
+               $entries = [map $_->[0],
-                           sort { $b->[1] cmp $a->[1] }
+                              sort { $b->[1] cmp $a->[1] }
-                              map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
+                                 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
-                                 @$entries];
+                                    @$entries];
-            my (@dirs, @nondirs);
+               my (@dirs, @nondirs);
-            my $statgrp = add $grp aio_group sub {
+               my $statgrp = add $grp aio_group sub {
-               $grp->result (\@dirs, \@nondirs);
+                  $grp->result (\@dirs, \@nondirs);
-            };
+               };
-            limit $statgrp $maxreq;
+               limit $statgrp $maxreq;
-            feed $statgrp sub {
+               feed $statgrp sub {
-               return unless @$entries;
+                  return unless @$entries;
-               my $entry = pop @$entries;
+                  my $entry = pop @$entries;
-               aioreq_pri $pri;
+                  aioreq_pri $pri;
-               add $statgrp aio_stat "$path/$entry/.", sub {
+                  add $statgrp aio_stat "$path/$entry/.", sub {
-                  if ($_[0] < 0) {
+                     if ($_[0] < 0) {
-                     push @nondirs, $entry;
+                        push @nondirs, $entry;
-                  } else {
+                     } else {
-                     # need to check for real directory
+                        # need to check for real directory
-                     aioreq_pri $pri;
+                        aioreq_pri $pri;
-                     add $statgrp aio_lstat "$path/$entry", sub {
+                        add $statgrp aio_lstat "$path/$entry", sub {
-                        if (-d _) {
+                           if (-d _) {
-                           push @dirs, $entry;
+                              push @dirs, $entry;
-                           unless (--$ndirs) {
+                              unless (--$ndirs) {
-                              push @nondirs, @$entries;
+                                 push @nondirs, @$entries;
-                              feed $statgrp;
+                                 feed $statgrp;
+                              }
+                           } else {
+                              push @nondirs, $entry;
                            }
-                        } else {
-                           push @nondirs, $entry;
                         }
                      }
-                  }
+                  };
                };
             };
          };
       };
+      $grp
-   };
+   }
+}
+=item aio_rmtree $path, $callback->($status)
+Delete a directory tree starting (and including) C<$path>, return the
+status of the final C<rmdir> only.  This is a composite request that
+uses C<aio_scandir> to recurse into and rmdir directories, and unlink
+everything else.
+=cut
+sub aio_rmtree;
+sub aio_rmtree($;$) {
+   aio_block {
+      my ($path, $cb) = @_;
+      my $pri = aioreq_pri;
+      my $grp = aio_group $cb;
+      aioreq_pri $pri;
+      add $grp aio_scandir $path, 0, sub {
+         my ($dirs, $nondirs) = @_;
+         my $dirgrp = aio_group sub {
+            add $grp aio_rmdir $path, sub {
+               $grp->result ($_[0]);
+            };
+         };
+         (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
+         (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
+         add $grp $dirgrp;
+      };
-   $grp
+      $grp
+   }
 }
 =item aio_fsync $fh, $callback->($status)
 Asynchronously call fsync on the given filehandle and call the callback
 that are being processed by C<IO::AIO::poll_cb> in one call, respectively
 the maximum amount of time (default C<0>, meaning infinity) spent in
 C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
 of time C<poll_cb> is allowed to use).
+Setting C<max_poll_time> to a non-zero value creates an overhead of one
+syscall per request processed, which is not normally a problem unless your
+callbacks are really really fast or your OS is really really slow (I am
+not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
 Setting these is useful if you want to ensure some level of
 interactiveness when perl is not fast enough to process all requests in
 time.
 For interactive programs, values such as C<0.01> to C<0.1> should be fine.
 Example: Install an Event watcher that automatically calls
-IO::AIO::poll_some with low priority, to ensure that other parts of the
+IO::AIO::poll_cb with low priority, to ensure that other parts of the
 program get the CPU sometimes even under high AIO load.
    # try not to spend much more than 0.1s in poll_cb
    IO::AIO::max_poll_time 0.1;
               poll => 'r', nice => 1,
               cb => &IO::AIO::poll_cb);
 =item IO::AIO::poll_wait
+If there are any outstanding requests and none of them in the result
-Wait till the result filehandle becomes ready for reading (simply does a
+phase, wait till the result filehandle becomes ready for reading (simply
-C<select> on the filehandle. This is useful if you want to synchronously
+does a C<select> on the filehandle. This is useful if you want to
-wait for some requests to finish).
+synchronously wait for some requests to finish).
 See C<nreqs> for an example.
 =item IO::AIO::poll
 Waits until some requests have been handled.
+Returns the number of requests processed, but is otherwise strictly
-Strictly equivalent to:
+equivalent to:
    IO::AIO::poll_wait, IO::AIO::poll_cb
-      if IO::AIO::nreqs;
 =item IO::AIO::flush
 Wait till all outstanding AIO requests have been handled.
 Strictly equivalent to:
    IO::AIO::poll_wait, IO::AIO::poll_cb
       while IO::AIO::nreqs;
+=back
 =head3 CONTROLLING THE NUMBER OF THREADS
+=over
 =item IO::AIO::min_parallel $nthreads
 Set the minimum number of AIO threads to C<$nthreads>. The current
 default is C<8>, which means eight asynchronous operations can execute
 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.
 Sets the maximum number of outstanding requests to C<$nreqs>. If you
-to queue up more than this number of requests, the next call to the
+do queue up more than this number of requests, the next call to the
 C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
 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<max_oustsanding> is mainly useful in simple scripts (with low values) or
 as a stop gap to shield against fatal memory overflow (with large values).
+=back
 =head3 STATISTICAL INFORMATION
+=over
 =item IO::AIO::nreqs
 Returns the number of requests currently in the ready, execute or pending
 states (i.e. for which their callback has not been invoked yet).
 =back
 =cut
-# support function to convert a fd into a perl filehandle
-sub _fd2fh {
-   return undef if $_[0] < 0;
-   # try to generate nice filehandles
-   my $sym = "IO::AIO::fd#$_[0]";
-   local *$sym;
-   open *$sym, "+<&=$_[0]"      # usually works under any unix
-      or open *$sym, "<&=$_[0]" # cygwin needs this
-      or open *$sym, ">&=$_[0]" # or this
-      or return undef;
-   *$sym
-}
 min_parallel 8;
-END {
+END { flush }
-   min_parallel 1;
-   flush;
-};
 1;
 =head2 FORK BEHAVIOUR
 bytes of memory. In addition, stat requests need a stat buffer (possibly
 a few hundred bytes), readdir requires a result buffer and so on. Perl
 scalars and other data passed into aio requests will also be locked and
 will consume memory till the request has entered the done state.
-This is now awfully much, so queuing lots of requests is not usually a
+This is not awfully much, so queuing lots of requests is not usually a
 problem.
 Per-thread usage:
 In the execution phase, some aio requests require more memory for

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.86 by root, Sat Oct 28 23:32:29 2006 UTC vs. Revision 1.116 by root, Wed Oct 3 21:27:51 2007 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.86 by root, Sat Oct 28 23:32:29 2006 UTC vs.
Revision 1.116 by root, Wed Oct 3 21:27:51 2007 UTC