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

Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.93 by root, Wed Oct 1 14:49:23 2008 UTC vs.
Revision 1.129 by root, Mon Jun 29 11:04:09 2009 UTC

 AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
 =cut
-our $VERSION = 4.3;
+our $VERSION = 4.42;
 =head1 SYNOPSIS
    use AnyEvent;
    use AnyEvent::Handle;
    my $handle =
       AnyEvent::Handle->new (
          fh => \*STDIN,
          on_eof => sub {
-            $cv->broadcast;
+            $cv->send;
          },
       );
    # send some request line
    $handle->push_write ("getinfo\015\012");
 treatment of characters applies to this module as well.
 All callbacks will be invoked with the handle object as their first
 argument.
-=head2 SIGPIPE is not handled by this module
-SIGPIPE is not handled by this module, so one of the practical
-requirements of using it is to ignore SIGPIPE (C<$SIG{PIPE} =
-'IGNORE'>). At least, this is highly recommend in a networked program: If
-you use AnyEvent::Handle in a filter program (like sort), exiting on
-SIGPIPE is probably the right thing to do.
 =head1 METHODS
 =over 4
 =item B<new (%args)>
 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
+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 I<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<$!> set to <0>.
 and no read request is in the queue (unlike read queue callbacks, this
 callback will only be called when at least one octet of data is in the
 read buffer).
 To access (and remove data from) the read buffer, use the C<< ->rbuf >>
-method or access the C<$handle->{rbuf}> member directly.
+method or access the C<$handle->{rbuf}> member directly. Note that you
+must not enlarge or modify the read buffer, you can only remove data at
+the beginning from it.
 When an EOF condition is detected then AnyEvent::Handle will first try to
 feed all the remaining data to the queued callbacks and C<on_read> before
 calling the C<on_eof> callback. If no progress can be made, then a fatal
 error will be raised (with C<$!> set to C<EPIPE>).
 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.
+B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
+passing in the wrong integer will lead to certain crash. This most often
+happens when one uses a stylish C<< tls => 1 >> and is surprised about the
+segmentation fault.
 See the C<< ->starttls >> method for when need to start TLS negotiation later.
 =item tls_ctx => $ssl_ctx
 Use the given C<Net::SSLeay::CTX> object to create the new TLS connection
    $self->{fh} or Carp::croak "mandatory argument fh is missing";
    AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
-   if ($self->{tls}) {
-      require Net::SSLeay;
-      $self->starttls (delete $self->{tls}, delete $self->{tls_ctx});
+   $self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
-   }
+      if $self->{tls};
    $self->{_activity} = AnyEvent->now;
    $self->_timeout;
    $self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
 }
 sub _shutdown {
    my ($self) = @_;
-   delete $self->{_tw};
+   delete @$self{qw(_tw _rw _ww fh rbuf wbuf on_read _queue)};
-   delete $self->{_rw};
-   delete $self->{_ww};
-   delete $self->{fh};
    &_freetls;
-   delete $self->{on_read};
-   delete $self->{_queue};
 }
 sub _error {
    my ($self, $errno, $fatal) = @_;
    $! = $errno;
    if ($self->{on_error}) {
       $self->{on_error}($self, $fatal);
-   } else {
+   } elsif ($self->{fh}) {
       Carp::croak "AnyEvent::Handle uncaught error: $!";
    }
 }
 =item $fh = $handle->fh
 }
 =item $handle->autocork ($boolean)
 Enables or disables the current autocork behaviour (see C<autocork>
-constructor argument).
+constructor argument). Changes will only take effect on the next write.
 =cut
+sub autocork {
+   $_[0]{autocork} = $_[1];
+}
 =item $handle->no_delay ($boolean)
 Enables or disables the C<no_delay> setting (see constructor argument of
 the same name for details).
            ->($self, @_);
    }
    if ($self->{tls}) {
       $self->{_tls_wbuf} .= $_[0];
       &_dotls ($self);
    } else {
       $self->{wbuf} .= $_[0];
       $self->_drain_wbuf;
    }
 =cut
 register_write_type netstring => sub {
    my ($self, $string) = @_;
-   sprintf "%d:%s,", (length $string), $string
+   (length $string) . ":$string,"
 };
 =item packstring => $format, $data
 An octet string prefixed with an encoded length. The encoding C<$format>
    ) {
       $self->_error (&Errno::ENOSPC, 1), return;
    }
    while () {
+      # we need to use a separate tls read buffer, as we must not receive data while
+      # we are draining the buffer, and this can only happen with TLS.
+      $self->{rbuf} .= delete $self->{_tls_rbuf} if exists $self->{_tls_rbuf};
       my $len = length $self->{rbuf};
       if (my $cb = shift @{ $self->{_queue} }) {
          unless ($cb->($self)) {
             if ($self->{_eof}) {
 =item $handle->rbuf
 Returns the read buffer (as a modifiable lvalue).
-You can access the read buffer directly as the C<< ->{rbuf} >> member, if
+You can access the read buffer directly as the C<< ->{rbuf} >>
-you want.
+member, if you want. However, the only operation allowed on the
+read buffer (apart from looking at it) is removing data from its
+beginning. Otherwise modifying or appending to it is not allowed and will
+lead to hard-to-track-down bugs.
 NOTE: The read buffer should only be used or modified if the C<on_read>,
 C<push_read> or C<unshift_read> methods are used. The other read methods
 automatically manage the read buffer.
 An octet string prefixed with an encoded length. The encoding C<$format>
 uses the same format as a Perl C<pack> format, but must specify a single
 integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
 optional C<!>, C<< < >> or C<< > >> modifier).
-DNS over TCP uses a prefix of C<n>, EPP uses a prefix of C<N>.
+For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
+EPP uses a prefix of C<N> (4 octtes).
 Example: read a block of data prefixed by its length in BER-encoded
 format (very efficient).
    $handle->push_read (packstring => "w", sub {
    }
 };
 =item json => $cb->($handle, $hash_or_arrayref)
-Reads a JSON object or array, decodes it and passes it to the callback.
+Reads a JSON object or array, decodes it and passes it to the
+callback. When a parse error occurs, an C<EBADMSG> error will be raised.
 If a C<json> object was passed to the constructor, then that will be used
 for the final decode, otherwise it will create a JSON coder expecting UTF-8.
 This read type uses the incremental parser available with JSON version
    my $rbuf = \$self->{rbuf};
    my $json = $self->{json} ||= JSON->new->utf8;
    sub {
-      my $ref = $json->incr_parse ($self->{rbuf});
+      my $ref = eval { $json->incr_parse ($self->{rbuf}) };
       if ($ref) {
          $self->{rbuf} = $json->incr_text;
          $json->incr_text = "";
          $cb->($self, $ref);
          1
+      } elsif ($@) {
+         # error case
+         $json->incr_skip;
+         $self->{rbuf} = $json->incr_text;
+         $json->incr_text = "";
+         $self->_error (&Errno::EBADMSG);
+         ()
       } else {
          $self->{rbuf} = "";
          ()
       }
    }
 };
          if ($len > 0) {
             $self->{_activity} = AnyEvent->now;
             if ($self->{tls}) {
                Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
                &_dotls ($self);
             } else {
                $self->_drain_rbuf unless $self->{_in_drain};
             }
          }
       });
    }
 }
+# poll the write BIO and send the data if applicable
 sub _dotls {
    my ($self) = @_;
-   my $buf;
+   my $tmp;
    if (length $self->{_tls_wbuf}) {
-      while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
+      while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
-         substr $self->{_tls_wbuf}, 0, $len, "";
+         substr $self->{_tls_wbuf}, 0, $tmp, "";
       }
    }
-   while (defined ($buf = Net::SSLeay::read ($self->{tls}))) {
+   while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
-      unless (length $buf) {
+      unless (length $tmp) {
          # let's treat SSL-eof as we treat normal EOF
          delete $self->{_rw};
          $self->{_eof} = 1;
          &_freetls;
       }
-      $self->{rbuf} .= $buf;
+      $self->{_tls_rbuf} .= $tmp;
       $self->_drain_rbuf unless $self->{_in_drain};
       $self->{tls} or return; # tls session might have gone away in callback
    }
-   my $err = Net::SSLeay::get_error ($self->{tls}, -1);
+   $tmp = Net::SSLeay::get_error ($self->{tls}, -1);
-   if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
+   if ($tmp != Net::SSLeay::ERROR_WANT_READ ()) {
-      if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
+      if ($tmp == Net::SSLeay::ERROR_SYSCALL ()) {
          return $self->_error ($!, 1);
-      } elsif ($err == Net::SSLeay::ERROR_SSL ())  {
+      } elsif ($tmp == Net::SSLeay::ERROR_SSL ()) {
          return $self->_error (&Errno::EIO, 1);
       }
-      # all others are fine for our purposes
+      # all other errors are fine for our purposes
    }
-   if (length ($buf = Net::SSLeay::BIO_read ($self->{_wbio}))) {
+   while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
-      $self->{wbuf} .= $buf;
+      $self->{wbuf} .= $tmp;
       $self->_drain_wbuf;
    }
 }
 =item $handle->starttls ($tls[, $tls_ctx])
 =cut
 sub starttls {
    my ($self, $ssl, $ctx) = @_;
+   require Net::SSLeay;
-   Carp::croak "it is an error to call starttls more than once on an Anyevent::Handle object"
+   Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
       if $self->{tls};
    if ($ssl eq "accept") {
       $ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
       Net::SSLeay::set_accept_state ($ssl);
 sub stoptls {
    my ($self) = @_;
    if ($self->{tls}) {
-      Net::SSLeay::shutdown $self->{tls};
+      Net::SSLeay::shutdown ($self->{tls});
       &_dotls;
       # we don't give a shit. no, we do, but we can't. no...
       # we, we... have to use openssl :/
    delete @$self{qw(_rbio _wbio _tls_wbuf)};
 }
 sub DESTROY {
-   my $self = shift;
+   my ($self) = @_;
    &_freetls;
    my $linger = exists $self->{linger} ? $self->{linger} : 3600;
          @linger = ();
       });
    }
 }
+=item $handle->destroy
+Shuts down the handle object as much as possible - this call ensures that
+no further callbacks will be invoked and resources will be freed as much
+as possible. You must not call any methods on the object afterwards.
+Normally, you can just "forget" any references to an AnyEvent::Handle
+object and it will simply shut down. This works in fatal error and EOF
+callbacks, as well as code outside. It does I<NOT> work in a read or write
+callback, so when you want to destroy the AnyEvent::Handle object from
+within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
+that case.
+The handle might still linger in the background and write out remaining
+data, as specified by the C<linger> option, however.
+=cut
+sub destroy {
+   my ($self) = @_;
+   $self->DESTROY;
+   %$self = ();
+}
 =item AnyEvent::Handle::TLS_CTX
 This function creates and returns the Net::SSLeay::CTX object used by
 default for TLS mode.
    }
 }
 =back
+=head1 NONFREQUENTLY ASKED QUESTIONS
+=over 4
+=item I C<undef> the AnyEvent::Handle reference inside my callback and
+still get further invocations!
+That's because AnyEvent::Handle keeps a reference to itself when handling
+read or write callbacks.
+It is only safe to "forget" the reference inside EOF or error callbacks,
+from within all other callbacks, you need to explicitly call the C<<
+->destroy >> method.
+=item I get different callback invocations in TLS mode/Why can't I pause
+reading?
+Unlike, say, TCP, TLS connections do not consist of two independent
+communication channels, one for each direction. Or put differently. The
+read and write directions are not independent of each other: you cannot
+write data unless you are also prepared to read, and vice versa.
+This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
+callback invocations when you are not expecting any read data - the reason
+is that AnyEvent::Handle always reads in TLS mode.
+During the connection, you have to make sure that you always have a
+non-empty read-queue, or an C<on_read> watcher. At the end of the
+connection (or when you no longer want to use it) you can call the
+C<destroy> method.
+=item How do I read data until the other side closes the connection?
+If you just want to read your data into a perl scalar, the easiest way
+to achieve this is by setting an C<on_read> callback that does nothing,
+clearing the C<on_eof> callback and in the C<on_error> callback, the data
+will be in C<$_[0]{rbuf}>:
+   $handle->on_read (sub { });
+   $handle->on_eof (undef);
+   $handle->on_error (sub {
+      my $data = delete $_[0]{rbuf};
+      undef $handle;
+   });
+The reason to use C<on_error> is that TCP connections, due to latencies
+and packets loss, might get closed quite violently with an error, when in
+fact, all data has been received.
+It is usually better to use acknowledgements when transferring data,
+to make sure the other side hasn't just died and you got the data
+intact. This is also one reason why so many internet protocols have an
+explicit QUIT command.
+=item I don't want to destroy the handle too early - how do I wait until
+all data has been written?
+After writing your last bits of data, set the C<on_drain> callback
+and destroy the handle in there - with the default setting of
+C<low_water_mark> this will be called precisely when all data has been
+written to the socket:
+   $handle->push_write (...);
+   $handle->on_drain (sub {
+      warn "all data submitted to the kernel\n";
+      undef $handle;
+   });
+=back
 =head1 SUBCLASSING AnyEvent::Handle
 In many cases, you might want to subclass AnyEvent::Handle.
 To make this easier, a given version of AnyEvent::Handle uses these

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Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents): Revision 1.93 by root, Wed Oct 1 14:49:23 2008 UTC vs. Revision 1.129 by root, Mon Jun 29 11:04:09 2009 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.93 by root, Wed Oct 1 14:49:23 2008 UTC vs.
Revision 1.129 by root, Mon Jun 29 11:04:09 2009 UTC