[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent/Handle.pm

Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.65 by root, Fri Jun 6 11:05:16 2008 UTC vs.
Revision 1.88 by root, Thu Aug 21 23:48:35 2008 UTC

 package AnyEvent::Handle;
 no warnings;
-use strict;
+use strict qw(subs vars);
 use AnyEvent ();
 use AnyEvent::Util qw(WSAEWOULDBLOCK);
 use Scalar::Util ();
 use Carp ();
 AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
 =cut
-our $VERSION = 4.15;
+our $VERSION = 4.233;
 =head1 SYNOPSIS
    use AnyEvent;
    use AnyEvent::Handle;
 This module is a helper module to make it easier to do event-based I/O on
 filehandles. For utility functions for doing non-blocking connects and accepts
 on sockets see L<AnyEvent::Util>.
+The L<AnyEvent::Intro> tutorial contains some well-documented
+AnyEvent::Handle examples.
 In the following, when the documentation refers to of "bytes" then this
 means characters. As sysread and syswrite are used for all I/O, their
 treatment of characters applies to this module as well.
 All callbacks will be invoked with the handle object as their first
 =item fh => $filehandle [MANDATORY]
 The filehandle this L<AnyEvent::Handle> object will operate on.
-NOTE: The filehandle will be set to non-blocking (using
+NOTE: The filehandle will be set to non-blocking mode (using
-AnyEvent::Util::fh_nonblocking).
+C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
+that mode.
 =item on_eof => $cb->($handle)
-Set the callback to be called when an end-of-file condition is detcted,
+Set the callback to be called when an end-of-file condition is detected,
 i.e. in the case of a socket, when the other side has closed the
 connection cleanly.
+For sockets, this just means that the other side has stopped sending data,
+you can still try to write data, and, in fact, one can return from the eof
+callback and continue writing data, as only the read part has been shut
+down.
-While not mandatory, it is highly recommended to set an eof callback,
+While not mandatory, it is I<highly> recommended to set an eof callback,
 otherwise you might end up with a closed socket while you are still
 waiting for data.
+If an EOF condition has been detected but no C<on_eof> callback has been
+set, then a fatal error will be raised with C<$!> set to <0>.
 =item on_error => $cb->($handle, $fatal)
 This is the error callback, which is called when, well, some error
 occured, such as not being able to resolve the hostname, failure to
 connect or a read error.
 Some errors are fatal (which is indicated by C<$fatal> being true). On
-fatal errors the handle object will be shut down and will not be
+fatal errors the handle object will be shut down and will not be usable
+(but you are free to look at the current C<< ->rbuf >>). Examples of fatal
+errors are an EOF condition with active (but unsatisifable) read watchers
+(C<EPIPE>) or I/O errors.
-usable. Non-fatal errors can be retried by simply returning, but it is
+Non-fatal errors can be retried by simply returning, but it is recommended
-recommended to simply ignore this parameter and instead abondon the handle
+to simply ignore this parameter and instead abondon the handle object
-object when this callback is invoked.
+when this callback is invoked. Examples of non-fatal errors are timeouts
+C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
 On callback entrance, the value of C<$!> contains the operating system
 error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>).
 While not mandatory, it is I<highly> recommended to set this callback, as
 This sets the callback that is called when the write buffer becomes empty
 (or when the callback is set and the buffer is empty already).
 To append to the write buffer, use the C<< ->push_write >> method.
+This callback is useful when you don't want to put all of your write data
+into the queue at once, for example, when you want to write the contents
+of some file to the socket you might not want to read the whole file into
+memory and push it into the queue, but instead only read more data from
+the file when the write queue becomes empty.
 =item timeout => $fractional_seconds
 If non-zero, then this enables an "inactivity" timeout: whenever this many
 seconds pass without a successful read or write on the underlying file
 handle, the C<on_timeout> callback will be invoked (and if that one is
-missing, an C<ETIMEDOUT> error will be raised).
+missing, a non-fatal C<ETIMEDOUT> error will be raised).
 Note that timeout processing is also active when you currently do not have
 any outstanding read or write requests: If you plan to keep the connection
 idle then you should disable the timout temporarily or ignore the timeout
-in the C<on_timeout> callback.
+in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
+restart the timeout.
 Zero (the default) disables this timeout.
 =item on_timeout => $cb->($handle)
 =item rbuf_max => <bytes>
 If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
 when the read buffer ever (strictly) exceeds this size. This is useful to
-avoid denial-of-service attacks.
+avoid some forms of denial-of-service attacks.
 For example, a server accepting connections from untrusted sources should
 be configured to accept only so-and-so much data that it cannot act on
 (for example, when expecting a line, an attacker could send an unlimited
 amount of data without a callback ever being called as long as the line
 isn't finished).
+=item autocork => <boolean>
+When disabled (the default), then C<push_write> will try to immediately
+write the data to the handle, if possible. This avoids having to register
+a write watcher and wait for the next event loop iteration, but can
+be inefficient if you write multiple small chunks (on the wire, this
+disadvantage is usually avoided by your kernel's nagle algorithm, see
+C<no_delay>, but this option can save costly syscalls).
+When enabled, then writes will always be queued till the next event loop
+iteration. This is efficient when you do many small writes per iteration,
+but less efficient when you do a single write only per iteration (or when
+the write buffer often is full). It also increases write latency.
+=item no_delay => <boolean>
+When doing small writes on sockets, your operating system kernel might
+wait a bit for more data before actually sending it out. This is called
+the Nagle algorithm, and usually it is beneficial.
+In some situations you want as low a delay as possible, which can be
+accomplishd by setting this option to a true value.
+The default is your opertaing system's default behaviour (most likely
+enabled), this option explicitly enables or disables it, if possible.
 =item read_size => <bytes>
-The default read block size (the amount of bytes this module will try to read
+The default read block size (the amount of bytes this module will
-during each (loop iteration). Default: C<8192>.
+try to read during each loop iteration, which affects memory
+requirements). Default: C<8192>.
 =item low_water_mark => <bytes>
 Sets the amount of bytes (default: C<0>) that make up an "empty" write
 buffer: If the write reaches this size or gets even samller it is
 considered empty.
+Sometimes it can be beneficial (for performance reasons) to add data to
+the write buffer before it is fully drained, but this is a rare case, as
+the operating system kernel usually buffers data as well, so the default
+is good in almost all cases.
 =item linger => <seconds>
 If non-zero (default: C<3600>), then the destructor of the
-AnyEvent::Handle object will check wether there is still outstanding write
+AnyEvent::Handle object will check whether there is still outstanding
-data and will install a watcher that will write out this data. No errors
+write data and will install a watcher that will write this data to the
-will be reported (this mostly matches how the operating system treats
+socket. No errors will be reported (this mostly matches how the operating
-outstanding data at socket close time).
+system treats outstanding data at socket close time).
-This will not work for partial TLS data that could not yet been
+This will not work for partial TLS data that could not be encoded
-encoded. This data will be lost.
+yet. This data will be lost.
 =item tls => "accept" | "connect" | Net::SSLeay::SSL object
-When this parameter is given, it enables TLS (SSL) mode, that means it
+When this parameter is given, it enables TLS (SSL) mode, that means
-will start making tls handshake and will transparently encrypt/decrypt
+AnyEvent will start a TLS handshake as soon as the conenction has been
-data.
+established and will transparently encrypt/decrypt data afterwards.
 TLS mode requires Net::SSLeay to be installed (it will be loaded
-automatically when you try to create a TLS handle).
+automatically when you try to create a TLS handle): this module doesn't
+have a dependency on that module, so if your module requires it, you have
+to add the dependency yourself.
-For the TLS server side, use C<accept>, and for the TLS client side of a
+Unlike TCP, TLS has a server and client side: for the TLS server side, use
-connection, use C<connect> mode.
+C<accept>, and for the TLS client side of a connection, use C<connect>
+mode.
 You can also provide your own TLS connection object, but you have
 to make sure that you call either C<Net::SSLeay::set_connect_state>
 or C<Net::SSLeay::set_accept_state> on it before you pass it to
 AnyEvent::Handle.
-See the C<starttls> method if you need to start TLs negotiation later.
+See the C<< ->starttls >> method for when need to start TLS negotiation later.
 =item tls_ctx => $ssl_ctx
-Use the given Net::SSLeay::CTX object to create the new TLS connection
+Use the given C<Net::SSLeay::CTX> object to create the new TLS connection
 (unless a connection object was specified directly). If this parameter is
 missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
 =item json => JSON or JSON::XS object
 This is the json coder object used by the C<json> read and write types.
 If you don't supply it, then AnyEvent::Handle will create and use a
-suitable one, which will write and expect UTF-8 encoded JSON texts.
+suitable one (on demand), which will write and expect UTF-8 encoded JSON
+texts.
 Note that you are responsible to depend on the JSON module if you want to
 use this functionality, as AnyEvent does not have a dependency itself.
 =item filter_r => $cb
 =item filter_w => $cb
-These exist, but are undocumented at this time.
+These exist, but are undocumented at this time. (They are used internally
+by the TLS code).
 =back
 =cut
    }
    $self->{_activity} = AnyEvent->now;
    $self->_timeout;
-   $self->on_drain (delete $self->{on_drain}) if $self->{on_drain};
+   $self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
+   $self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
+   $self->start_read
+      if $self->{on_read};
    $self
 }
 sub _shutdown {
    delete $self->{_rw};
    delete $self->{_ww};
    delete $self->{fh};
    $self->stoptls;
+   delete $self->{on_read};
+   delete $self->{_queue};
 }
 sub _error {
    my ($self, $errno, $fatal) = @_;
    }
 }
 =item $fh = $handle->fh
-This method returns the file handle of the L<AnyEvent::Handle> object.
+This method returns the file handle used to create the L<AnyEvent::Handle> object.
 =cut
 sub fh { $_[0]{fh} }
    $_[0]{on_eof} = $_[1];
 }
 =item $handle->on_timeout ($cb)
-Replace the current C<on_timeout> callback, or disables the callback
+Replace the current C<on_timeout> callback, or disables the callback (but
-(but not the timeout) if C<$cb> = C<undef>. See C<timeout> constructor
+not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
-argument.
+argument and method.
 =cut
 sub on_timeout {
    $_[0]{on_timeout} = $_[1];
+}
+=item $handle->autocork ($boolean)
+Enables or disables the current autocork behaviour (see C<autocork>
+constructor argument).
+=cut
+=item $handle->no_delay ($boolean)
+Enables or disables the C<no_delay> setting (see constructor argument of
+the same name for details).
+=cut
+sub no_delay {
+   $_[0]{no_delay} = $_[1];
+   eval {
+      local $SIG{__DIE__};
+      setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
+   };
 }
 #############################################################################
 =item $handle->timeout ($seconds)
             $self->_error ($!, 1);
          }
       };
       # try to write data immediately
-      $cb->();
+      $cb->() unless $self->{autocork};
       # if still data left in wbuf, we need to poll
       $self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
          if length $self->{wbuf};
    };
 ways, the "simple" way, using only C<on_read> and the "complex" way, using
 a queue.
 In the simple case, you just install an C<on_read> callback and whenever
 new data arrives, it will be called. You can then remove some data (if
-enough is there) from the read buffer (C<< $handle->rbuf >>) if you want
+enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
-or not.
+leave the data there if you want to accumulate more (e.g. when only a
+partial message has been received so far).
 In the more complex case, you want to queue multiple callbacks. In this
 case, AnyEvent::Handle will call the first queued callback each time new
 data arrives (also the first time it is queued) and removes it when it has
 done its job (see C<push_read>, below).
             # handle xml
          });
       });
    });
-Example 2: Implement a client for a protocol that replies either with
+Example 2: Implement a client for a protocol that replies either with "OK"
-"OK" and another line or "ERROR" for one request, and 64 bytes for the
+and another line or "ERROR" for the first request that is sent, and 64
-second request. Due tot he availability of a full queue, we can just
+bytes for the second request. Due to the availability of a queue, we can
-pipeline sending both requests and manipulate the queue as necessary in
+just pipeline sending both requests and manipulate the queue as necessary
-the callbacks:
+in the callbacks.
-   # request one
+When the first callback is called and sees an "OK" response, it will
+C<unshift> another line-read. This line-read will be queued I<before> the
+64-byte chunk callback.
+   # request one, returns either "OK + extra line" or "ERROR"
    $handle->push_write ("request 1\015\012");
    # we expect "ERROR" or "OK" as response, so push a line read
    $handle->push_read (line => sub {
       # if we got an "OK", we have to _prepend_ another line,
             ...
          });
       }
    });
-   # request two
+   # request two, simply returns 64 octets
    $handle->push_write ("request 2\015\012");
    # simply read 64 bytes, always
    $handle->push_read (chunk => 64, sub {
       my $response = $_[1];
    if (
       defined $self->{rbuf_max}
       && $self->{rbuf_max} < length $self->{rbuf}
    ) {
-      return $self->_error (&Errno::ENOSPC, 1);
+      $self->_error (&Errno::ENOSPC, 1), return;
    }
    while () {
-      no strict 'refs';
       my $len = length $self->{rbuf};
       if (my $cb = shift @{ $self->{_queue} }) {
          unless ($cb->($self)) {
             if ($self->{_eof}) {
                # no progress can be made (not enough data and no data forthcoming)
-               $self->_error (&Errno::EPIPE, 1), last;
+               $self->_error (&Errno::EPIPE, 1), return;
             }
             unshift @{ $self->{_queue} }, $cb;
             last;
          }
             && !@{ $self->{_queue} }     # and the queue is still empty
             && $self->{on_read}          # but we still have on_read
          ) {
             # no further data will arrive
             # so no progress can be made
-            $self->_error (&Errno::EPIPE, 1), last
+            $self->_error (&Errno::EPIPE, 1), return
                if $self->{_eof};
             last; # more data might arrive
          }
       } else {
          delete $self->{_rw};
          last;
       }
    }
+   if ($self->{_eof}) {
+      if ($self->{on_eof}) {
-   $self->{on_eof}($self)
+         $self->{on_eof}($self)
-      if $self->{_eof} && $self->{on_eof};
+      } else {
+         $self->_error (0, 1);
+      }
+   }
    # may need to restart read watcher
    unless ($self->{_rw}) {
       $self->start_read
          if $self->{on_read} || @{ $self->{_queue} };
       $cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
       1
    }
 };
-# compatibility with older API
-sub push_read_chunk {
-   $_[0]->push_read (chunk => $_[1], $_[2]);
-}
-sub unshift_read_chunk {
-   $_[0]->unshift_read (chunk => $_[1], $_[2]);
-}
 =item line => [$eol, ]$cb->($handle, $line, $eol)
 The callback will be called only once a full line (including the end of
 line marker, C<$eol>) has been read. This line (excluding the end of line
 marker) will be passed to the callback as second argument (C<$line>), and
 =cut
 register_read_type line => sub {
    my ($self, $cb, $eol) = @_;
-   $eol = qr|(\015?\012)| if @_ < 3;
+   if (@_ < 3) {
+      # this is more than twice as fast as the generic code below
+      sub {
+         $_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
+         $cb->($_[0], $1, $2);
+         1
+      }
+   } else {
-   $eol = quotemeta $eol unless ref $eol;
+      $eol = quotemeta $eol unless ref $eol;
-   $eol = qr|^(.*?)($eol)|s;
+      $eol = qr|^(.*?)($eol)|s;
-   sub {
+      sub {
-      $_[0]{rbuf} =~ s/$eol// or return;
+         $_[0]{rbuf} =~ s/$eol// or return;
-      $cb->($_[0], $1, $2);
+         $cb->($_[0], $1, $2);
+         1
-      1
+      }
    }
 };
-# compatibility with older API
-sub push_read_line {
-   my $self = shift;
-   $self->push_read (line => @_);
-}
-sub unshift_read_line {
-   my $self = shift;
-   $self->unshift_read (line => @_);
-}
 =item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
 Makes a regex match against the regex object C<$accept> and returns
 everything up to and including the match.
 register_read_type packstring => sub {
    my ($self, $cb, $format) = @_;
    sub {
       # when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
-      defined (my $len = eval { unpack $format, $_[0]->{rbuf} })
+      defined (my $len = eval { unpack $format, $_[0]{rbuf} })
          or return;
+      $format = length pack $format, $len;
+      # bypass unshift if we already have the remaining chunk
+      if ($format + $len <= length $_[0]{rbuf}) {
+         my $data = substr $_[0]{rbuf}, $format, $len;
+         substr $_[0]{rbuf}, 0, $format + $len, "";
+         $cb->($_[0], $data);
+      } else {
-      # remove prefix
+         # remove prefix
-      substr $_[0]->{rbuf}, 0, (length pack $format, $len), "";
+         substr $_[0]{rbuf}, 0, $format, "";
-      # read rest
+         # read remaining chunk
-      $_[0]->unshift_read (chunk => $len, $cb);
+         $_[0]->unshift_read (chunk => $len, $cb);
+      }
       1
    }
 };
    require Storable;
    sub {
       # when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
-      defined (my $len = eval { unpack "w", $_[0]->{rbuf} })
+      defined (my $len = eval { unpack "w", $_[0]{rbuf} })
          or return;
+      my $format = length pack "w", $len;
+      # bypass unshift if we already have the remaining chunk
+      if ($format + $len <= length $_[0]{rbuf}) {
+         my $data = substr $_[0]{rbuf}, $format, $len;
+         substr $_[0]{rbuf}, 0, $format + $len, "";
+         $cb->($_[0], Storable::thaw ($data));
+      } else {
-      # remove prefix
+         # remove prefix
-      substr $_[0]->{rbuf}, 0, (length pack "w", $len), "";
+         substr $_[0]{rbuf}, 0, $format, "";
-      # read rest
+         # read remaining chunk
-      $_[0]->unshift_read (chunk => $len, sub {
+         $_[0]->unshift_read (chunk => $len, sub {
-         if (my $ref = eval { Storable::thaw ($_[1]) }) {
+            if (my $ref = eval { Storable::thaw ($_[1]) }) {
-            $cb->($_[0], $ref);
+               $cb->($_[0], $ref);
-         } else {
+            } else {
-            $self->_error (&Errno::EBADMSG);
+               $self->_error (&Errno::EBADMSG);
+            }
-         }
+         });
-      });
+      }
+      1
    }
 };
 =back
    # basically, this is deep magic (because SSL_read should have the same issues)
    # but the openssl maintainers basically said: "trust us, it just works".
    # (unfortunately, we have to hardcode constants because the abysmally misdesigned
    # and mismaintained ssleay-module doesn't even offer them).
    # http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
+   #
+   # in short: this is a mess.
+   #
+   # note that we do not try to kepe the length constant between writes as we are required to do.
+   # we assume that most (but not all) of this insanity only applies to non-blocking cases,
+   # and we drive openssl fully in blocking mode here.
    Net::SSLeay::CTX_set_mode ($self->{tls},
       (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
       | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
    $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
 =over 4
 =item * all constructor arguments become object members.
 At least initially, when you pass a C<tls>-argument to the constructor it
-will end up in C<< $handle->{tls} >>. Those members might be changes or
+will end up in C<< $handle->{tls} >>. Those members might be changed or
 mutated later on (for example C<tls> will hold the TLS connection object).
 =item * other object member names are prefixed with an C<_>.
 All object members not explicitly documented (internal use) are prefixed

Diff Legend

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Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents): Revision 1.65 by root, Fri Jun 6 11:05:16 2008 UTC vs. Revision 1.88 by root, Thu Aug 21 23:48:35 2008 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.65 by root, Fri Jun 6 11:05:16 2008 UTC vs.
Revision 1.88 by root, Thu Aug 21 23:48:35 2008 UTC