# -*- Mode: perl; indent-tabs-mode: nil -*-
#
# The contents of this file are subject to the Mozilla Public
# License Version 1.1 (the "License"); you may not use this file
# except in compliance with the License. You may obtain a copy of
# the License at http://www.mozilla.org/MPL/
#
# Software distributed under the License is distributed on an "AS
# IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
# implied. See the License for the specific language governing
# rights and limitations under the License.
#
# The Original Code is the Bugzilla Bug Tracking System.
#
# The Initial Developer of the Original Code is Netscape Communications
# Corporation. Portions created by Netscape are
# Copyright (C) 1998 Netscape Communications Corporation. All
# Rights Reserved.
#
# Contributor(s): Bradley Baetz <bbaetz@acm.org>

package Bugzilla::Error;

use strict;
use base qw(Exporter);

@Bugzilla::Error::EXPORT = qw(ThrowCodeError ThrowTemplateError ThrowUserError);

use Bugzilla::Config;
use Bugzilla::Util;

sub _throw_error {
    my ($name, $error, $vars, $unlock_tables) = @_;

    $vars ||= {};

    $vars->{error} = $error;

    Bugzilla->dbh->do("UNLOCK TABLES") if $unlock_tables;

    print Bugzilla->cgi->header();

    my $template = Bugzilla->template;
    $template->process($name, $vars)
      || ThrowTemplateError($template->error());

    exit;
}

sub ThrowUserError {
    _throw_error("global/user-error.html.tmpl", @_);
}

sub ThrowCodeError {
    _throw_error("global/code-error.html.tmpl", @_);
}

sub ThrowTemplateError {
    my ($template_err) = @_;

    my $vars = {};

    $vars->{'template_error_msg'} = $template_err;
    $vars->{'error'} = "template_error";

    my $template = Bugzilla->template;

    # Try a template first; but if this one fails too, fall back
    # on plain old print statements.
    if (!$template->process("global/code-error.html.tmpl", $vars)) {
        my $maintainer = Param('maintainer');
        my $error = html_quote($vars->{'template_error_msg'});
        my $error2 = html_quote($template->error());
        print <<END;
        <tt>
          <p>
            Bugzilla has suffered an internal error. Please save this page and 
            send it to $maintainer with details of what you were doing at the 
            time this message appeared.
          </p>
          <script type="text/javascript"> <!--
          document.write("<p>URL: " + 
                          document.location.href.replace(/&/g,"&amp;")
                                                .replace(/</g,"&lt;")
                                                .replace(/>/g,"&gt;") + "</p>");
          // -->
          </script>
          <p>Template->process() failed twice.<br>
          First error: $error<br>
          Second error: $error2</p>
        </tt>
END
    }
    exit;
}

1;

__END__

=head1 NAME

Bugzilla::Error - Error handling utilities for Bugzilla

=head1 SYNOPSIS

  use Bugzilla::Error;

  ThrowUserError("error_tag",
                 { foo => 'bar' });

=head1 DESCRIPTION

Various places throughout the Bugzilla codebase need to report errors to the
user. The C<Throw*Error> family of functions allow this to be done in a
generic and localisable manner.

=head1 FUNCTIONS

=over 4

=item C<ThrowUserError>

This function takes an error tag as the first argument, and an optional hashref
of variables as a second argument. These are used by the
I<global/user-error.html.tmpl> template to format the error, using the passed
in variables as required.

An optional third argument may be supplied. If present (and defined), then the
error handling code will unlock the database tables. In the long term, this
argument will go away, to be replaced by transactional C<rollback> calls. There
is no timeframe for doing so, however.

=item C<ThrowCodeError>

This function is used when an internal check detects an error of some sort.
This usually indicates a bug in Bugzilla, although it can occur if the user
manually constructs urls without correct parameters.

This function's behaviour is similar to C<ThrowUserError>, except that the
template used to display errors is I<global/code-error.html.tmpl>. In addition
if the hashref used as the optional second argument contains a key I<variables>
then the contents of the hashref (which is expected to be another hashref) will
be displayed after the error message, as a debugging aid.

=item C<ThrowTemplateError>

This function should only be called if a C<template-<gt>process()> fails.
It tries another template first, because often one template being
broken or missing doesn't mean that they all are. But it falls back to
a print statement as a last-ditch error.

=back

=head1 SEE ALSO

L<Bugzilla|Bugzilla>
