1 files changed, 147 insertions, 0 deletions
diff --git a/Spline/Log.pm b/Spline/Log.pm
new file mode 100644
index 0000000..f56d5f0
--- /dev/null
+++ b/Spline/Log.pm
@@ -0,0 +1,147 @@
+#!/usr/bin/perl
+=pod
+
+=head1 NAME
+
+Spline::Log - Utilities for logging
+
+=head1 SYNOPSIS
+
+    use Spline::Log qw(...);
+
+    set_verbose($bool);
+    set_log_context($context);
+    debug($message);
+    info($message);
+
+=head1 DESCRIPTION
+
+=cut
+
+package Spline::Log;
+
+use strict;
+use warnings;
+use feature 'say';
+
+use base 'Exporter';
+our @EXPORT = qw();
+our @EXPORT_OK = qw(
+    set_verbose
+    set_log_context
+    debug
+    info
+); 
+
+my $context = undef;
+my $verbose = 0;
+
+=head2 set_verbose
+
+    set_verbose($bool);
+
+Specify if you want to see the debug messages. If the supplied value
+is true, you will see this messages, otherwise only the info messages
+are logged.
+
+=cut
+
+sub set_verbose($) {
+    my $value = shift;
+
+    if ($value) {
+        $verbose = 1;
+    }
+    else {
+        $verbose = 0;
+    }
+}
+
+=head2 set_log_context
+
+    set_log_context($context);
+
+Set the logging context, that should be added to all messages. If you
+may have interleaving log lines, you could use this context to tag the
+correlating lines.
+
+This method set the new context and returns the previous value.
+
+=cut
+
+sub set_log_context($) {
+    my $old = $context;
+    $context = '' . shift;
+    return $old;
+}
+
+=head2 debug
+
+    debug($message);
+
+Lop the supplied message, but only if verbose is set. The message is
+prepended with the logging context (if defined).
+
+=cut
+
+sub debug($) {
+    my $msg = shift;
+
+    if ($verbose) {
+        _log($msg);
+    }
+}
+
+=head2 info
+
+    info($message);
+
+Log the supplied message, regardless of the verbosity. The message is
+prepended with the logging context (if defined).
+
+=cut
+
+sub info($) {
+    my $msg = shift;
+    _log($msg);
+}
+
+=head2 _get_context
+
+    $context = _get_context();
+
+If the logging context is defined, return the context followd by a
+colon and a space (ready for output). If the context is undefined an
+empty space is returned.
+
+=cut
+
+sub _get_context() {
+    return '' unless defined $context;
+    return "$context: ";
+}
+
+=head2 _log
+
+    _log($msg);
+
+Log the supplied message. The message is prepended with the logging
+context (if defined). So the log format is something like this:
+
+    CONTEXT: MESSAGE
+
+=cut
+
+sub _log($) {
+    my $msg = shift;
+    say _get_context() . $msg;
+}
+
+=head1 AUTHOR
+
+Alexander Sulfrian <alex@spline.inf.fu-berlin.de>
+
+=cut
+
+1;
+# vim: set et tabstop=4 tw=70: