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=head1 NAME |
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|
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AnyEvent::MP::DataConn - create socket connections between nodes |
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|
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=head1 SYNOPSIS |
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|
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use AnyEvent::MP::DataConn; |
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|
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=head1 DESCRIPTION |
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|
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This module can be used to create socket connections between the local and |
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a remote node in the aemp network. The socket can be used freely for any |
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purpose, and in most cases, this mechanism is a good way to transport big |
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chunks of binary data. |
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|
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The connections created by this module use the same security mechanisms |
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as normal AEMP connections (secure authentication, optional use of TLS), |
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and in fact, use the same listening port as AEMP connections, so when two |
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nodes can reach each other, they can, with high probability, creare a data |
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connection between them. |
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|
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The protocol is, however, not the AEMP transport protocol, so this will |
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only work between nodes implementing the "aemp-dataconn" protocol. |
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|
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=head1 FUNCTIONS |
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|
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=over 4 |
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|
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=cut |
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|
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package AnyEvent::MP::DataConn; |
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|
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use common::sense; |
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use Carp (); |
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use POSIX (); |
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|
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use AnyEvent (); |
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use AnyEvent::Util (); |
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|
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use AnyEvent::MP; |
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use AnyEvent::MP::Kernel (); |
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use AnyEvent::MP::Global (); |
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|
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our $ID = "a"; |
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our %STATE; |
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|
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# another node tells us to await a connection |
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sub _expect { |
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my ($id, $port, $timeout, $initfunc, @initdata) = @_; |
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|
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$STATE{$id} = { |
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id => $id, |
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to => (AE::timer $timeout, 0, sub { |
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$STATE{$id}{done}(undef); |
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}), |
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done => sub { |
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my ($hdl, $error) = @_; |
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|
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%{delete $STATE{$id}} = (); |
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|
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if (defined $hdl) { |
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(AnyEvent::MP::Kernel::load_func $initfunc)->(@initdata, $hdl); |
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} else { |
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kil $port, AnyEvent::MP::DataConn:: => $error; |
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} |
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}, |
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}; |
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} |
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|
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# AEMP::Transport call for dataconn-connections |
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sub _inject { |
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my ($conn, $error) = @_; |
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|
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my $hdl = defined $error ? undef : delete $conn->{hdl}; |
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my $id = $conn->{local_greeting}{dataconn_id} || $conn->{remote_greeting}{dataconn_id} |
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or return; |
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|
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$conn->destroy; |
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|
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($STATE{$id} or return)->{done}($hdl, $error); |
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} |
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|
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# actively connect to some other node |
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sub _connect { |
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my ($id, $node) = @_; |
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|
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my $state = $STATE{$id} |
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or return; |
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|
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my $addr = $AnyEvent::MP::Global::addr{$node}; |
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|
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@$addr |
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or return $state->{done}(undef, "$node: no listeners found"); |
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|
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# I love hardcoded constants ! |
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$state->{next} = AE::timer 0, 2, sub { |
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my $endpoint = shift @$addr |
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or return delete $state->{next}; |
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|
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my ($host, $port) = AnyEvent::Socket::parse_hostport $endpoint |
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or return; |
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|
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my $transport; $transport = AnyEvent::MP::Transport::mp_connect |
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$host, $port, |
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protocol => "aemp-dataconn", |
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local_greeting => { dataconn_id => $id }, |
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sub { $transport->destroy }, #TODO: destroys handshaked conenctions too early |
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; |
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}; |
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} |
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|
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=item AnyEvent::MP::DataConn::connect_to $node, $timeout, $initfunc, @initdata, $cb->($handle) |
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|
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Creates a socket connection between the local node and the node C<$node> |
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(which can also be specified as a port). One of the nodes must have |
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listening ports ("binds"). |
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|
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When the connection could be successfully created, the C<$initfunc> |
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will be called with the given C<@initdata> on the remote node (similar |
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to C<snd_to_func> or C<spawn>), and the C<AnyEvent::Handle> object |
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representing the remote connection end as additional argument. |
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|
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Also, the callback given as last argument will be called with the |
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AnyEvent::Handle object for the local side. |
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|
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The AnyEvent::Handle objects will be in a "quiescent" state - you could rip |
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out the file handle and forget about it, but it is recommended to use it, |
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as the security settings might have called for a TLS connection. If you |
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opt to use it, you at least have to set an C<on_error> callback. |
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|
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In case of any error (timeout etc.), nothing will be called on |
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the remote side, and the local port will be C<kil>'ed with an C<< |
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AnyEvent::MP::DataConn => "error message" >> kill reason. |
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|
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The timeout should be large enough to cover at least four network |
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round-trips and one message round-trip. |
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|
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Example: on node1, establish a connection to node2 and send a line of text, |
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one node2, provide a receiver function. |
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|
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# node1, code executes in some port context |
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AnyEvent::MP::DataConn::connect_to "node2", 5, "pkg::receiver", 1, sub { |
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my ($hdl) = @_; |
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warn "connection established, sending line.\n" |
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$hdl->push_write ("blabla\n") |
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}; |
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|
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# node2 |
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sub pkg::receiver { |
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my ($one, $hdl) = @_; |
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warn "connection established, wait for a line...\n" |
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|
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$hdl->push_read (line => sub { |
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warn "received a line: $_[1]\n"; |
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undef $hdl; |
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}); |
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} |
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|
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=cut |
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|
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sub connect_to($$$$@) { |
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my $cb = pop; |
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my ($node, $timeout, $initfunc, @initdata) = @_; |
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my $port = $SELF; |
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$node = node_of $node; |
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|
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my $id = (++$ID) . "\@$NODE"; |
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|
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# damn, why do my simple state hashes resemble objects so quickly |
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my $state = $STATE{$id} = { |
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id => (++$ID) . "\@$NODE", |
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to => (AE::timer $timeout, 0, sub { |
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$STATE{$id}{done}(undef, "$node: unable to establish connection within $timeout seconds"); |
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}), |
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done => sub { |
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my ($hdl, $error) = @_; |
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|
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delete $AnyEvent::MP::Global::ON_SETUP{$id}; |
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%{delete $STATE{$id}} = (); |
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|
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if (defined $hdl) { |
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$cb->($hdl); |
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} else { |
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kil $port, AnyEvent::MP::DataConn:: => $error; |
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} |
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}, |
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}; |
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|
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if (AnyEvent::MP::Kernel::port_is_local $node) { |
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return kil $port, AnyEvent::MP::DataConn:: => |
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"connect_to does not yet support local/local connections, please bug me about it"; |
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|
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} else { |
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AnyEvent::MP::Kernel::snd_to_func $node, |
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AnyEvent::MP::DataConn::_expect:: => $id, $port, $timeout, $initfunc, @initdata; |
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|
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$state->{wait} = sub { |
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if (my $addr = $AnyEvent::MP::Global::addr{$node}) { |
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delete $AnyEvent::MP::Global::ON_SETUP{$id}; |
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|
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# continue connect |
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if (@$addr) { |
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# node has listeners, so connect |
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_connect $id, $node; |
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} else { |
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# no listeners, ask it to connect to us |
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AnyEvent::MP::Kernel::snd_to_func $node, AnyEvent::MP::DataConn::_connect:: => $id, $NODE; |
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} |
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} else { |
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# wait for the next global setup handshake |
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# due to the round-trip at the beginning, this should never be necessary |
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$AnyEvent::MP::Global::ON_SETUP{$id} = $state->{wait}; |
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}; |
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}; |
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|
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# we actually have to make sure that the connection arrives after the expect message, and |
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# the easiest way to do this is to use an rpc call. |
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AnyEvent::MP::Kernel::snd_on $node, port { $state->{wait}() }; |
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} |
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} |
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|
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=back |
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|
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=head1 SEE ALSO |
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|
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L<AnyEvent::MP>. |
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|
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=head1 AUTHOR |
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|
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Marc Lehmann <schmorp@schmorp.de> |
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http://home.schmorp.de/ |
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|
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=cut |
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