#!/usr/bin/perl
#
# logformatter - highlight a Cirrus test log (ginkgo or bats)
#
# Adapted from https://raw.githubusercontent.com/edsantiago/greasemonkey/podman-ginkgo-highlight
#
package LibPod::CI::LogFormatter;

use v5.14;
use utf8;

# Grumble. CI system doesn't have 'open'
binmode STDIN,  ':utf8';
binmode STDOUT, ':utf8';

use strict;
use warnings;

(our $ME = $0) =~ s|.*/||;

our $VERSION = '0.1';

# For debugging, show data structures using DumpTree($var)
#use Data::TreeDumper; $Data::TreeDumper::Displayaddress = 0;

###############################################################################
# BEGIN user-customizable section

# Stylesheet for highlighting or de-highlighting parts of lines
our $CSS = <<'END_CSS';
/* wrap long lines - don't require user to scroll right */
pre        { line-break: normal; overflow-wrap: normal; white-space: pre-wrap; }

/* synopsis table at top */
table.synopsis { border: none; border-collapse: collapse; margin-left: 2em; margin-top: 2ex; }
.synopsis th   { font-weight: normal; font-size: 110%; text-align: right; }
.synopsis td   { font-weight: bold;   font-size: 120%; font-family: monospace; }

/* test results */
.testname  { font-size: 125%; color: #444; }
.boring    { color: #999; }
.timestamp { color: #999; }
.log-debug { color: #999; }
.log-info  { color: #333; }
.log-warn  { color: #f60; }
.log-error { color: #900; font-weight: bold; }
.log-skip  { color: #F90; }
.log-slow  { background: #FF0; color: #000; font-weight: bold; }
.subtest   { background: #eee; }
.subsubtest { color: #F39; font-weight: bold; }
.string    { color: #00c; }
.command   { font-weight: bold; color: #000; }
.changed   { color: #000; font-weight: bold; }

/* links to source files: not as prominent as links to errors */
a.codelink:link    { color: #000; }
a.codelink:visited { color: #666; }
a.codelink:hover   { background: #000; color: #999; }

/* The timing tests at bottom: remove underline, it's too cluttery. */
a.timing           { text-decoration: none; }
.timing:hover      { background: #FF9; }  /* highlight row for easy reading */

/* BATS styles */
.bats-passed    { color: #393; }
.bats-failed    { color: #F00; font-weight: bold; }
.bats-skipped   { color: #F90; }
.bats-log       { color: #900; }
.bats-log-esm   { color: #b00; font-weight: bold; }

.bats-summary   { font-size: 150%; }

/* error titles: display next to timestamp, not on separate line */
h2 { display: inline; }
END_CSS

# END   user-customizable section
###############################################################################

###############################################################################
# BEGIN boilerplate args checking, usage messages

sub usage {
    print  <<"END_USAGE";
Usage: $ME [OPTIONS] TEST_NAME

$ME is a filter; it HTMLifies an input stream (presumably
Ginkgo or BATS log results), writing HTML results to an output file
but passing stdin unmodified to stdout. It is intended to run in
the Cirrus CI environment.

Parameters:

    TEST_NAME   descriptive name; output file will be TEST_NAME.log.html

OPTIONS:

  --help         display this message
  --man          display program man page
  --version      display program name and version
END_USAGE

    exit;
}

# Command-line options.  Note that this operates directly on @ARGV !
our $debug   = 0;
our $force   = 0;
our $verbose = 0;
our $NOT     = '';              # print "blahing the blah$NOT\n" if $debug
sub handle_opts {
    use Getopt::Long;
    GetOptions(
        'debug!'     => \$debug,
        'dry-run|n!' => sub { $NOT = ' [NOT]' },
        'force'      => \$force,
        'verbose|v'  => \$verbose,

        help         => \&usage,
        version      => sub { print "$ME version $VERSION\n"; exit 0 },
    ) or die "Try `$ME --help' for help\n";
}

# END   boilerplate args checking, usage messages
###############################################################################

############################## CODE BEGINS HERE ###############################

# The term is "modulino".
__PACKAGE__->main()                                     unless caller();

# Main code.
sub main {
    # Note that we operate directly on @ARGV, not on function parameters.
    # This is deliberate: it's because Getopt::Long only operates on @ARGV
    # and there's no clean way to make it use @_.
    handle_opts();                      # will set package globals

    # In case someone is tempted to run us on the command line
    die "$ME: this is a filter, not an interactive script\n" if -t *STDIN;

    # Fetch command-line arguments.  Barf if too many.
    my $test_name = shift(@ARGV)
        or die "$ME: missing TEST_NAME argument; try $ME --help\n";
    warn "$ME: Too many arguments; ignoring extras. try $ME --help\n" if @ARGV;

    format_log($test_name);
}


sub format_log {
    my $test_name = shift;              # in: e.g. 'integration_test'

    my $outfile = "$test_name.log.html";
    my $out_tmp = "$outfile.tmp.$$";
    open my $out_fh, '>:utf8', $out_tmp
        or warn "$ME: Cannot create $out_tmp: $!\n";

    # Boilerplate: HTML headers for output file
    print { $out_fh } <<"END_HTML"      if $out_fh;
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html
        PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
         "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en-US">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>$test_name</title>
<style type="text/css">
$CSS
</style>

<!-- on page load, go to bottom: that's where the error summary is -->
<script language="javascript">
function scrollToBottom() {
    if (window.scrollY < 10) {
        window.scrollTo(0, document.body.scrollHeight);
    }
}
window.addEventListener("load", scrollToBottom, false);
</script>
</head>
<body>
END_HTML

    # Synopsis of this job: show job environment, links to PR and Cirrus
    print { $out_fh } "<h2>Synopsis</h2>\n<hr/>\n",
        job_synopsis($test_name), "<hr/>\n";

    # State variables
    my $previous_timestamp = '';  # timestamp of previous line
    my $cirrus_task;              # Cirrus task number, used for linking
    my $git_commit;               # git SHA, used for linking to source files
    my $in_failure;               # binary flag: are we in an error dump?
    my $in_timing;                # binary flag: are we in the timing section?
    my $after_divider = 0;        # Count of lines after seeing '-----'
    my $current_output;           # for removing duplication
    my $looks_like_bats;          # binary flag: for detecting BATS results
    my $looks_like_python;        #   " "   "  : for colorizing python tests
    my %bats_count;               # For summary line: count of pass/fail/skip

    # When running in cirrus, we have the commit SHA
    $git_commit = $ENV{CIRRUS_CHANGE_IN_REPO};

    print { $out_fh } "<pre> <!-- begin processed output -->\n";

    # Assume rootful prompt, check for rootless (here and in log itself, below)
    my $Prompt = '#';
    $Prompt = '$' if $test_name =~ /rootless/;

    # Main loop: read input, one line at a time, and write out reformatted
  LINE:
    while (my $line = <STDIN>) {
        print $line;                    # Immediately dump back to stdout

        $Prompt = '$' if $line =~ /Runner executing .* as rootless /;

        # Remain robust in face of errors: always write stdout even if no HTML
        next LINE if ! $out_fh;

        chomp $line;
        $line =~ s/\0//g;               # Some log files have NULs????
        $line = escapeHTML($line);

        # Temporarily strip off leading timestamp
        $line =~ s/^(\[\+\d+s\]\s)//;
        my $timestamp = $1 || '';
        if ($previous_timestamp && $timestamp eq $previous_timestamp) {
            $timestamp = ' ' x length($timestamp);
        }
        elsif ($timestamp) {
            $previous_timestamp = $timestamp;
        }

        # Try to identify the git commit we're working with...
        if ($line =~ m!/define.gitCommit=([0-9a-f]+)!) {
            $git_commit = $1;
        }
        # ...so we can link to specific lines in source files
        if ($git_commit) {
            #           1  12  3                 34     4 5   526  6
            $line =~ s{^(.*)(\/(containers\/[^/]+)(\/\S+):(\d+))(.*)$}
                      {$1<a class="codelink" href='https://github.com/$3/blob/$git_commit$4#L$5'>$2</a>$6};

            # Same, for python errors
            #           1  12  3                 34         4             5   526
            $line =~ s{^(.*)(\/(containers\/[^/]+)(\/\S+\.py).*,\s+line\s+(\d+))(,\s+in.*)$}
                      {$1<a class="codelink" href='https://github.com/$3/blob/$git_commit$4#L$5'>$2</a>$6};
        }

        # Try to identify the cirrus task
        if ($line =~ /cirrus-task-(\d+)/) {
            $cirrus_task = $1;
        }

        # BATS handling. This will recognize num_tests both at start and end
        if ($line =~ /^1\.\.(\d+)$/) {
            $looks_like_bats = 1;
            $bats_count{expected_total} = $1;
            undef $looks_like_python;
        }
        # Since the number of tests can't always be predicted, recognize
        # some leading text strings that indicate BATS output to come.
        elsif ($line =~ /^TAP\s+version\s/ || $line =~ m!/test-apiv2!) {
            $looks_like_bats = 1;
            $bats_count{expected_total} = -1; # Expect to be overridden at end!
            undef $looks_like_python;
        }

        # 'python -m unittest' means we're starting some pythony stuff
        elsif ($line =~ m!/python.*\sunittest\s!) {
            $looks_like_python = 1;
            undef $looks_like_bats;
        }
        elsif ($looks_like_python && $line =~ m!Ran\s+(\d+)\s+tests\s+in\s!) {
            # End of python tests. However, we're still likely to see a
            # summary line saying 'OK' or 'FAILED'. Deal with that by
            # resetting $looks_like_python to 0, which the next elsif catches
            $bats_count{expected_total} += $1;
            $looks_like_python = 0;
            print { $out_fh } "</div>\n"            if $in_failure;
            undef $in_failure;
        }
        elsif (defined($looks_like_python) && !$looks_like_python) {
            # The final python summary line. Show it in its appropriate color.
            if ($line =~ /^\s*(OK|FAILED)\s+\(/) {
                undef $looks_like_python;
                my $css = ($1 eq 'OK' ? 'passed' : 'failed');
                print { $out_fh } "<span class=\"timestamp\">$timestamp</span>"
                    if $timestamp;
                print { $out_fh } "<span class='bats-$css'>", $line, "</span>\n";
                next LINE;
            }
        }

        if ($looks_like_bats) {
            my $css;

            # Readability: /long/path/to/podman -> podman (hover for full path)
            # Also make it boldface, to make commands stand out
            $line =~ s{^(#\s+(#|\$)\s+)(\S+/)(podman\S*)(\s.*)}
                      {$1<b><span title="$3$4">$4</span>$5</b>};

            if    ($line =~ /^ok\s.*\s# skip/) { $css = 'skipped' }
            elsif ($line =~ /^ok\s/)           { $css = 'passed'  }
            elsif ($line =~ /^not\s+ok\s/)     { $css = 'failed'  }
            elsif ($line =~ /^#\s#\|\s/)       { $css = 'log-esm' }
            elsif ($line =~ /^#\s/)            { $css = 'log'     }

            # Link to source file. This is ugly: we have to hardcode 'podman'
            # and 'test/system' because there's no way to get them from log.
            #
            #          1  2      2               13     4         43           5
            $line =~ s{(in(\stest)?\s+file\s+\S+/)(\S+\.(bats|bash)),\s+line\s+(\d+)}{$1<a class="codelink" href="https://github.com/containers/podman/blob/$git_commit/test/system/$3#L$5">$3, line $5</a>};

            if ($css) {
                # Make it linkable, e.g. foo.html#t--00001
                if ($line =~ /^(not\s+)?ok\s+(\d+)\s+(.*)/) {
                    $line = sprintf("<a name='t--%05d'>%s</a>", $2, $line);

                    push @{$bats_count{__fail_list}}, [ $2, $3 ] if $1;
                }
                $line = "<span class='bats-$css'>$line</span>";

                $bats_count{$css}++;
            }

            print { $out_fh } "<span class=\"timestamp\">$timestamp</span>"
                if $timestamp;
            print { $out_fh } $line, "\n";
            next LINE;
        }
        elsif ($looks_like_python) {
            my $css;

            if    ($line =~ /\s\.\.\.\sskipped/) { $css = 'skipped' }
            elsif ($line =~ /\s\.\.\.\sok\s*$/)  { $css = 'passed'  }
            elsif ($line =~ /\s\.\.\.\sFAIL/)    { $css = 'failed'  }
            elsif ($line =~ /^\s*={40}/)         {
                # Begins a block of multiple lines including a stack trace
                print { $out_fh } "<div class='log-error'>\n" unless $in_failure;
                $in_failure = 1;
            }

            if ($css) {
                $line = "<span class='bats-$css'>$line</span>";

                $bats_count{$css}++;
            }
            print { $out_fh } "<span class=\"timestamp\">$timestamp</span>"
                if $timestamp;
            print { $out_fh } $line, "\n";
            next LINE;
        }

        # Timing section at the bottom of the page
        if ($line =~ / timing results\s*$/) {
            $in_timing = 1;
        }
        elsif ($in_timing) {
            if ($line =~ /^(\S.*\S)\s+(\d+\.\d+)\s*$/) {
                my ($name, $time) = ($1, $2);
                my $id = make_id($1, 'timing');

                # Try to column-align the timing numbers. Some test names
                # will be longer than our max - oh well.
                my $spaces = 80 - length(unescapeHTML($name));
                $spaces = 1 if $spaces < 1;
                $spaces++ if $time < 10;
                my $spacing = ' ' x $spaces;
                $line = qq{<span class="timing"><a href="#t--$id">$name</a>$spacing$time</span>};
            }
            else {
                $in_timing = 0;
            }
        }

        #
        # Ginkgo error reformatting
        #
        if ($line =~ /^.{1,4} (Failure|Panic)( in .*)? \[/) {
            # Begins a block of multiple lines including a stack trace
            print { $out_fh } "<div class='log-error'>\n";
            $in_failure = 1;
        }
        elsif ($line =~ /^-----------/) {
            if ($in_failure) {
                # Ends a stack trace block
                $in_failure = 0;
                print { $out_fh } "</div>\n";
            }
            $after_divider = 1;

            print { $out_fh } "</pre>\n<hr />\n<pre>\n";
            # Always show timestamp at start of each new test
            $previous_timestamp = '';
            next LINE;
        }
        # (bindings test sometimes emits 'Running' with leading bullet char)
        elsif ($line =~ s!^•?Running:!<span class="boring">$Prompt</span>!) {
            # Highlight the important (non-boilerplate) podman command.
            $line =~ s/\s+--remote\s+/ /g;      # --remote takes no args
            # Strip out the global podman options, but show them on hover
            $line =~ s{(\S+\/podman(-remote)?)((\s+--(root|runroot|runtime|tmpdir|storage-opt|conmon|cgroup-manager|network-backend|network-config-dir|storage-driver|events-backend|url) \S+)*)(.*)}{
                my ($full_path, $remote, $options, $args) = ($1, $2||'', $3, $6);

                $options =~ s/^\s+//;
                # Separate each '--foo bar' with newlines for readability
                $options =~ s/ --/\n--/g;
                qq{<span title="$full_path"><b>podman$remote</b></span> <span class=\"boring\" title=\"$options\">[options]</span><b>$args</b>};
            }e;
            $current_output = '';
        }
        # Grrr. 'output:' usually just tells us what we already know.
        elsif ($line =~ /^output:/) {
            $current_output =~ s!^\s+|\s+$!!g;  # Trim leading/trailing blanks
            $current_output =~ s/\s+/ /g;       # Collapse multiple spaces
            if ($line eq "output: $current_output" || $line eq 'output: ') {
                next LINE;
            }
        }
        elsif ($line =~ /^Error:/ || $line =~ / level=(warning|error) /) {
            $line = "<span class='log-warn'>" . $line . "</span>";
        }
        elsif ($line =~ /^panic:/) {
            $line = "<span class='log-error'>" . $line . "</span>";
        }
        else {
            $current_output .= ' ' . $line;
        }


        # Two lines after each divider, there's a test name. Make it
        # an anchor so we can link to it later.
        if ($after_divider++ == 2) {
            # Sigh. There is no actual marker. Assume that anything with
            ## two leading spaces then alpha or hyphen (not slashes) is
            ## a test name.
            if ($line =~ /^  [a-zA-Z-]/) {
                my $id = make_id($line, 'anchor');

                $line = "<a name='t--$id'><h2>$line</h2></a>";
            }
        }

        # Make SKIPPING and SLOW TEST visible
        $line =~ s!(\[SKIPPING\].*)!<span class="log-skip">$1</span>!;
        $line =~ s!(\[SLOW TEST.*\])!<span class="log-slow">$1</span>!;

        # Highlight test name when it appears in the middle of commands.
        # But make it boring, because we already have the test name in large
        # bold just above. (Except in skipped tests).
        $line =~ s!^(\s*)(\[It\]\s+.*)!$1<span class="testname">$2</span>!;

        # Failure name corresponds to a previously-seen block.
        #              1  2           2        3             3   14           4
        if ($line =~ /^(\[(Fail|Panic!)\] .* \[(It|BeforeEach)\] )([A-Za-z-].*)/) {
            my ($lhs, $type, $ginkgo_fluff, $testname) = ($1, $2, $3, $4);
            my $id = make_id($testname, 'link');

            $line = "<b>$lhs<a href='#t--$id'>$testname</a></b>";
        }

        print { $out_fh } "<span class=\"timestamp\">$timestamp</span>"
            if $timestamp;
        print { $out_fh } $line, "\n";
    }

    my $have_formatted_log;     # Set on success

    if ($out_fh) {
        # Summary line for BATS tests
        if (keys %bats_count) {
            print { $out_fh } "<hr/><span class='bats-summary'>Summary:";
            my $total = 0;
            my $comma = '';
            for my $class (qw(passed failed skipped)) {
                if (my $n = $bats_count{$class}) {
                    printf { $out_fh } "%s <span class='bats-%s'>%d %s</span>",
                        $comma, $class, $n, ucfirst($class);
                    $total += $n;
                    $comma = ',';
                }
            }

            printf { $out_fh } ". Total tests: $total";
            if (my $expected_total = $bats_count{expected_total}) {
                if ($total != $expected_total) {
                    print { $out_fh } " <span class='bats-failed'>(WARNING: expected $expected_total)</span>";
                }
            }
            print { $out_fh } "</span>\n";
        }

        print { $out_fh } "</pre>  <!-- end processed output -->\n";

        # Did we find a cirrus task? Link back.
        if ($cirrus_task) {
            print { $out_fh } <<"END_HTML";
<hr />
<h3>Cirrus <a href="https://cirrus-ci.com/task/$cirrus_task">task $cirrus_task</a></h3>
END_HTML
        }

        # FIXME: need a safe way to get TZ
        printf { $out_fh } <<"END_HTML", scalar(CORE::localtime);
<hr />
<small>Processed %s by $ME v$VERSION</small>
</body>
</html>
END_HTML

        if (close $out_fh) {
            if (rename $out_tmp => $outfile) {
                $have_formatted_log = 1;
            }
            else {
                warn "$ME: Could not rename $out_tmp: $!\n";
            }
        }
        else {
            warn "$ME: Error writing $out_tmp: $!\n";
        }
    }

    # Grumble. Github only shows the last N lines of the log... which is
    # anti-helpful when you want a quick synopsis of what failed. Write a
    # summary at the tail, to make it easier for humans to see what went wrong.
    if (my $fails = $bats_count{__fail_list}) {
        print  "\n";
        printf "Failed tests (%d):\n", scalar(@$fails);
        printf " - %d %s\n", @$_ for @$fails;
    }

    # If Cirrus magic envariables are available, write a link to results.
    # FIXME: it'd be so nice to make this a clickable live link.
    #
    # STATIC_MAGIC_BLOB is the name of a google-storage bucket. It is
    # unlikely to change often, but if it does you will suddenly start
    # seeing errors when trying to view formatted logs:
    #
    #    AccessDeniedAccess denied.Anonymous caller does not have storage.objects.get access to the Google Cloud Storage object.
    #
    # This happened in July 2020 when github.com/containers/libpod was
    # renamed to podman. If something like that ever happens again, you
    # will need to get the new magic blob value from:
    #
    #   https://console.cloud.google.com/storage/browser?project=libpod-218412
    #
    # You will also probably need to set the bucket Public by clicking on
    # the bucket name, then the Permissions tab. This is safe, since this
    # project is fully open-source.
    if ($have_formatted_log && $ENV{CIRRUS_TASK_ID}) {
        my $URL_BASE          = "https://storage.googleapis.com";
        my $STATIC_MAGIC_BLOB = "cirrus-ci-6707778565701632-fcae48";
        my $ARTIFACT_NAME     = "html";

        my $URL = "${URL_BASE}/${STATIC_MAGIC_BLOB}/artifacts/$ENV{CIRRUS_REPO_FULL_NAME}/$ENV{CIRRUS_TASK_ID}/${ARTIFACT_NAME}/${outfile}";

        print "\n\nAnnotated results:\n  $URL\n";
    }
}


#############
#  make_id  #  Given a test name, generate an anchor link name
#############
sub make_id {
    my $name = shift;                   # in: test title
    my $type = shift;                   # in: differentiator (anchor, link)

    state %counter;

    $name =~ s/^\s+|\s+$//g;            # strip leading/trailing whitespace
    $name =~ s/\&#\d+;//g;              # 'doesn&#39;t' -> 'doesnt'
    $name =~ s/\&quot;/-/g;             # '&quot;path&quot;' -> '-path-'
    $name =~ s/[^a-zA-Z0-9_-]/-/g;      # Convert non-alphanumeric to dash
    $name =~ s/-{3,}/-/g;               # '------' to just '-'

    # Keep a running tally of how many times we've seen this identifier
    # for this given type! This lets us cross-match, in the bottom of
    # the page, the first/second/third failure of a given test.
    $name .= "--" . ++$counter{$type}{$name};

    $name;
}


###############################################################################
# BEGIN job_synopsis and related helpers

##################
#  job_synopsis  #  Job details, links to github/cirrus
##################
sub job_synopsis {
    my $subtest_name = shift;           # e.g. integration_test

    my $s = <<"END_SYNOPSIS";
<table class="synopsis">
END_SYNOPSIS

    # PR 1234 - title of the pr
    my $pr_title = escapeHTML(_env_replace("{CIRRUS_CHANGE_TITLE}"));
    $s .= _tr("GitHub PR", sprintf("%s - %s",
                                   _a("{CIRRUS_PR}", "https://{CIRRUS_REPO_CLONE_HOST}/{CIRRUS_REPO_FULL_NAME}/pull/{CIRRUS_PR}"),
                                   $pr_title));

    # PR author, if signed-off-by
    if (my $msg = _env_replace("{CIRRUS_COMMIT_MESSAGE}")) {
        while ($msg =~ /^Signed-off-by:\s+(\S.*\S)$/gmi) {
            $s .= _tr("Author", escapeHTML($1));
        }
    }

    # eg "test fedora", "special_testing_rootless"
    # WARNING: As of 2020-10-05, $CIRRUS_TASK_NAME reflects the same
    # descriptive content as our $subtest_name argument (confirm via
    # cross-checking runner.sh:logformatter() vs cirrus.yml:&std_name_fmt).
    # If this ever becomes untrue, just add _tr("Subtest", $subtest_name).
    my $test_name = _env_replace("{CIRRUS_TASK_NAME}");
    # (Special-case cleanup: Cirrus\ quotes\ spaces; remove for readability).
    $test_name =~ s/\\\s+/ /g;
    $s .= _tr("Test name", $test_name);

    # Link to further Cirrus results, e.g. other runs.
    # Build is mostly boring, it's usually TASK that we want to see.
    $s .= _tr("Cirrus", sprintf("<small>Build %s</small> / <b>Task %s</b>",
                                _a("{CIRRUS_BUILD_ID}", "https://cirrus-ci.com/build/{CIRRUS_BUILD_ID}"),
                                _a("{CIRRUS_TASK_ID}", "https://cirrus-ci.com/task/{CIRRUS_TASK_ID}")));

    $s .= "</table>\n";
    return $s;
}


sub _tr {
    my ($th, $td) = @_;
    return "<tr><th>$th:</th><td>$td</td></tr>\n";
}

sub _a {
    my ($name, $href) = map { _env_replace($_) } @_;

    if ($href =~ /UNDEFINED/) {
        return "$name ($href)";
    }
    return "<a href='$href'>$name</a>";
}

sub _env_replace {
    my $s_in = shift;

    $s_in =~ s[\{(.*?)\}][$ENV{$1} || "[$1 UNDEFINED]"]ge;

    return $s_in;
}

# END   job_synopsis and related helpers
###############################################################################
# BEGIN html-formatting helpers

sub escapeHTML {
    my $s = shift;

    state %chars;
    %chars = ('&' => '&amp;', '<' => '&lt;', '>' => '&gt;', '"' => '&quot;', "'" => '&#39;')
        if keys(%chars) == 0;
    my $class = join('', sort keys %chars);
    $s =~ s/([$class])/$chars{$1}/ge;

    return $s;
}

sub unescapeHTML {
    my $s = shift;

    # We don't actually care about the character, only its length
    $s =~ s/\&\#?[a-z0-9]+;/./g;

    return $s;
}

# END   html-formatting helpers
###############################################################################

1;