1 files changed, 122 insertions, 0 deletions
diff --git a/lib/PublicInbox/IMAPClient.pm b/lib/PublicInbox/IMAPClient.pm
new file mode 100644
index 00000000..56001517
--- /dev/null
+++ b/lib/PublicInbox/IMAPClient.pm
@@ -0,0 +1,122 @@
+# This library is free software; you can redistribute it and/or modify it
+# under the same terms as Perl itself, either Perl version 5.8.0 or, at
+# your option, any later version of Perl 5 you may have available.
+#
+# The license for this file differs from the rest of public-inbox.
+#
+# Workaround some bugs in upstream Mail::IMAPClient <= 3.42 when
+# compression is enabled:
+# - reference cycle: https://rt.cpan.org/Ticket/Display.html?id=132654
+# - read starvation: https://rt.cpan.org/Ticket/Display.html?id=132720
+package PublicInbox::IMAPClient;
+use strict;
+use parent 'Mail::IMAPClient';
+unless (eval('use Mail::IMAPClient 3.43')) {
+require Errno;
+no warnings 'once';
+
+# RFC4978 COMPRESS
+*compress = sub {
+    my ($self) = @_;
+
+    # BUG? strict check on capability commented out for now...
+    #my $can = $self->has_capability("COMPRESS")
+    #return undef unless $can and $can eq "DEFLATE";
+
+    $self->_imap_command("COMPRESS DEFLATE") or return undef;
+
+    my $zcl = $self->_load_module("Compress-Zlib") or return undef;
+
+    # give caller control of args if desired
+    $self->Compress(
+        [
+            -WindowBits => -$zcl->MAX_WBITS(),
+            -Level      => $zcl->Z_BEST_SPEED()
+        ]
+    ) unless ( $self->Compress and ref( $self->Compress ) eq "ARRAY" );
+
+    my ( $rc, $do, $io );
+
+    ( $do, $rc ) = Compress::Zlib::deflateInit( @{ $self->Compress } );
+    unless ( $rc == $zcl->Z_OK ) {
+        $self->LastError("deflateInit failed (rc=$rc)");
+        return undef;
+    }
+
+    ( $io, $rc ) =
+      Compress::Zlib::inflateInit( -WindowBits => -$zcl->MAX_WBITS() );
+    unless ( $rc == $zcl->Z_OK ) {
+        $self->LastError("inflateInit failed (rc=$rc)");
+        return undef;
+    }
+
+    $self->{Prewritemethod} = sub {
+        my ( $self, $string ) = @_;
+
+        my ( $rc, $out1, $out2 );
+        ( $out1, $rc ) = $do->deflate($string);
+        ( $out2, $rc ) = $do->flush( $zcl->Z_PARTIAL_FLUSH() )
+          unless ( $rc != $zcl->Z_OK );
+
+        unless ( $rc == $zcl->Z_OK ) {
+            $self->LastError("deflate/flush failed (rc=$rc)");
+            return undef;
+        }
+
+        return $out1 . $out2;
+    };
+
+    # need to retain some state for Readmoremethod/Readmethod calls
+    my ( $Zbuf, $Ibuf ) = ( "", "" );
+
+    $self->{Readmoremethod} = sub {
+        my $self = shift;
+        return 1 if ( length($Zbuf) || length($Ibuf) );
+        $self->__read_more(@_);
+    };
+
+    $self->{Readmethod} = sub {
+        my ( $self, $fh, $buf, $len, $off ) = @_;
+
+        # get more data, but empty $Ibuf first if any data is left
+        my ( $lz, $li ) = ( length $Zbuf, length $Ibuf );
+        if ( $lz || !$li ) {
+            my $readlen = $self->Buffer || 4096;
+            my $ret = sysread( $fh, $Zbuf, $readlen, length $Zbuf );
+            $lz = length $Zbuf;
+            return $ret if ( !$ret && !$lz );    # $ret is undef or 0
+        }
+
+        # accumulate inflated data in $Ibuf
+        if ($lz) {
+            my ( $tbuf, $rc ) = $io->inflate( \$Zbuf );
+            unless ( $rc == $zcl->Z_OK ) {
+                $self->LastError("inflate failed (rc=$rc)");
+                return undef;
+            }
+            $Ibuf .= $tbuf;
+            $li = length $Ibuf;
+        }
+
+        if ( !$li ) {
+            # note: faking EAGAIN here is only safe with level-triggered
+            # I/O readiness notifications (select, poll).  Refactoring
+            # callers will be needed in the unlikely case somebody wants
+            # to use edge-triggered notifications (EV_CLEAR, EPOLLET).
+            $! = Errno::EAGAIN();
+            return undef;
+        }
+
+        # pull desired length of data from $Ibuf
+        my $tbuf = substr( $Ibuf, 0, $len );
+        substr( $Ibuf, 0, $len ) = "";
+        substr( $$buf, $off ) = $tbuf;
+
+        return length $tbuf;
+    };
+
+    return $self;
+};
+} # $Mail::IMAPClient::VERSION < 3.43
+
+1;