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lib/Developer/Dashboard/PageRuntime.pm  view on Meta::CPAN

        $self->_cleanup_saved_ajax_temp_files(@temp_files);
        die $@;
    }
    close $stdin;

    my $select = IO::Select->new( $stdout, $stderr );
    my $stream_error = '';
    my $disconnected = 0;
    eval {
        while (1) {
            my @ready = $select->can_read(0.25);
            last if !@ready && !$select->count;
            for my $fh (@ready) {
                my $continued = $self->_drain_saved_ajax_ready_handle(
                    fh            => $fh,
                    path          => $path,
                    select        => $select,
                    stdout        => $stdout,
                    stdout_writer => $stdout_writer,
                    stderr_writer => $stderr_writer,
                );
                if ( !$continued ) {
                    $disconnected = 1;
                    die "__DD_AJAX_STREAM_DISCONNECTED__\n";
                }
            }
        }
        1;
    } or do {
        $stream_error = $@ || "Saved ajax stream failed\n";
    };

    $self->_close_saved_ajax_streams( $select, $stdout, $stderr );
    my $fatal_error = '';
    if ($disconnected) {
        $self->_terminate_saved_ajax_process($pid);
    }
    elsif ( $stream_error ne '' ) {
        $self->_terminate_saved_ajax_process($pid);
        $fatal_error = $stream_error if !$self->_looks_like_stream_disconnect_error($stream_error);
    }
    waitpid( $pid, 0 );
    $self->_cleanup_saved_ajax_temp_files(@temp_files);
    die $fatal_error if $fatal_error ne '';
    return {
        disconnected => $disconnected ? 1 : 0,
        exit_code => $? >> 8,
        status    => $?,
    };
}

# _noop_writer(@parts)
# Accepts streamed output chunks when the caller does not need them.
# Input: zero or more ignored chunk parts.
# Output: empty string.
sub _noop_writer { return '' }

# _drain_saved_ajax_ready_handle(%args)
# Reads one ready saved-Ajax process pipe handle and forwards the chunk or error to the right writer.
# Input: ready fh, active select set, stdout fh, saved file path, and writer callbacks.
# Output: true value when streaming should continue, otherwise false when the client disconnected.
sub _drain_saved_ajax_ready_handle {
    my ( $self, %args ) = @_;
    my $fh            = $args{fh}            || die 'Missing ready handle';
    my $path          = $args{path}          || '';
    my $select        = $args{select}        || die 'Missing select set';
    my $stdout        = $args{stdout}        || die 'Missing stdout handle';
    my $stdout_writer = $args{stdout_writer} || \&_noop_writer;
    my $stderr_writer = $args{stderr_writer} || \&_noop_writer;
    my $chunk = '';
    my $bytes = $self->_stream_sysread( $fh, \$chunk );
    if ( !defined $bytes ) {
        return 1 if $!{EINTR};
        $stderr_writer->("Unable to read ajax stream for $path: $!\n");
        $select->remove($fh);
        close $fh;
        return 1;
    }
    if ( $bytes == 0 ) {
        $select->remove($fh);
        close $fh;
        return 1;
    }
    my $ready_fileno  = fileno($fh);
    my $stdout_fileno = fileno($stdout);
    if ( defined $ready_fileno && defined $stdout_fileno && $ready_fileno == $stdout_fileno ) {
        my $continued = $stdout_writer->($chunk);
        return defined $continued ? $continued : 1;
    }
    my $continued = $stderr_writer->($chunk);
    return defined $continued ? $continued : 1;
}

# _close_saved_ajax_streams($select, @handles)
# Closes the saved-Ajax select set and any remaining pipe handles after streaming stops.
# Input: IO::Select object plus zero or more pipe handles.
# Output: true value.
sub _close_saved_ajax_streams {
    my ( $self, $select, @handles ) = @_;
    if ( $select && eval { $select->can('handles') } ) {
        for my $fh ( $select->handles ) {
            next if !defined fileno($fh);
            $select->remove($fh);
            close $fh;
        }
    }
    for my $fh (@handles) {
        next if !defined $fh;
        next if !defined fileno($fh);
        close $fh;
    }
    return 1;
}

# _terminate_saved_ajax_process($pid)
# Stops one saved-Ajax worker process after stream cancellation or writer failure.
# Input: child process id integer.
# Output: true value.
sub _terminate_saved_ajax_process {
    my ( $self, $pid ) = @_;
    return 1 if !$pid;
    return 1 if !kill 0, $pid;
    kill 15, $pid;
    for ( 1 .. 20 ) {
        return 1 if !kill 0, $pid;
        sleep 0.05;
    }
    kill 9, $pid if kill 0, $pid;
    return 1;
}

# _looks_like_stream_disconnect_error($error)
# Detects writer failures that mean the browser stream was closed and the worker should just be stopped.
# Input: raw exception text from one writer callback.
# Output: boolean true when the error matches a disconnect or closed-stream condition.
sub _looks_like_stream_disconnect_error {
    my ( $self, $error ) = @_;
    return 1 if !defined $error || $error eq '';
    return 1 if $error =~ /^__DD_AJAX_STREAM_DISCONNECTED__/;
    return $error =~ /(broken pipe|client disconnected|connection reset|stream closed|connection aborted|write failed|closed handle)/i ? 1 : 0;
}

# _stream_sysread($fh, $chunk_ref)
# Reads one chunk from a saved-Ajax process pipe.
# Input: fh and scalar reference that receives the read chunk.
# Output: byte count or undef on read error.
sub _stream_sysread {
    my ( $self, $fh, $chunk_ref ) = @_;
    return sysread( $fh, ${$chunk_ref}, 8192 );
}

# _saved_ajax_command(%args)
# Resolves the process command used to execute one saved Ajax file.
# Input: saved file path.
# Output: command list suitable for open3.