=head1 NAME

Whatpm::CacheManifest - An HTML5 Cache Manifest Parser

=head1 SYNOPSIS

  use Whatpm::CacheManifest;
  
  my $manifest_uri = q<http://www.example.com/manifest>;
  my ($manifest_data, $manifest_base_uri)
      = some_function_to_retrieve_content ($manifest_uri);
  
  # or,
  
  my $manifest = Whatpm::CacheManifest->parse_byte_string
      ($manifest_data, $manifest_uri, $manifest_base_uri, sub {
        my %err = @_;
        warn $err{type}, "\n";
      });
  
  $manifest_data = Encode::decode ('utf-8', $manifest_data);
  my $manifest = Whatpm::CacheManifest->parse_char_string
      ($manifest_data, $manifest_uri, $manifest_base_uri, sub {
        my %err = @_;
        warn $err{type}, "\n";
      });
  
  # $manifest->[0]: Array reference of explicit URIs.
  # $manifest->[1]: Hash reference of fallback URIs.
  # $manifest->[2]: Array reference of online whitelist.

=head1 DESCRIPTION

The C<Whatpm::CacheManifest> module implements the parsing algorithm
for HTML5 cache manifest format, used to describe an offline Web
application.

=head1 METHODS

This module provides two class methods to parse cache manifests:

=over 4

=item I<$manifest> = Whatpm::CacheManifest->parse_byte_string (I<$manifest_bytes>, I<$manifest_uri>, I<$manifest_base_uri>, I<$onerror>)

=item I<$manifest> = Whatpm::CacheManifest->parse_char_string (I<$manifest_chars>, I<$manifest_uri>, I<$manifest_base_uri>, I<$onerror>)

=back

These methods parse a cache manifest and return that cache manifest
in the L<MANIFEST DATA STRUCTURE>.

Parameters:

=over 4

=item I<$manifest_bytes>

The content of the manifest files, as a Perl byte string.
It may or may not be a valid cache manifest.  It will be processed
as defined by HTML5 cache manifest parsing specification.
It will be interpreted as UTF-8 string, as defined in the specification.

=item I<$manfiest_chars>

The content of the manifest files, as a Perl character string.
It may or may not be a valid cache manifest.  It will be processed
as defined by HTML5 cache manifest parsing specification.  It may 
contain C<U+0000> C<NULL> characters; they are converted to
C<U+FFFD> C<REPLACEMENT CHARACTER>s as defined in the specification.

=item I<$manifest_uri>

The IRI of the cache manifest.

=item I<$manifest_base_uri>

The base IRI of the cache manifest.

=item I<$onerror>

The callback function that will be invoked if the manifest cache
has an error (or a warning).  It may be omitted.  If omitted, 
any error (or warning) is C<warn>ed with its C<type>.

@@ TBW

For the list of the error types, see Whatpm Error Types
<http://suika.fam.cx/gate/2005/sw/Whatpm%20Error%20Types>.

=back

In addition, a class method to check conformance of cache manifests
is provided:

=over 4

=item Whatpm::CacheManifest->check_manifest (I<$manifest>, I<$onerror>)

Check conformance of a cache manifest, given as I<$manifest>.

=over 4

=item I<$manifest>

The cache manifest to check, in the L<MANIFEST DATA STRUCTURE>.

=item I<$onerror>


The callback function that will be invoked if the manifest cache
has an error (or a warning).  It may be omitted.  If omitted, 
any error (or warning) is C<warn>ed with its C<type>.

@@ TBW

For the list of the error types, see Whatpm Error Types
<http://suika.fam.cx/gate/2005/sw/Whatpm%20Error%20Types>.

=back

A cache manifest is conforming if (a) it is correctly labeled
as a cache manifest (e.g. as Internet media type C<text/cache-manifest>)
in the transfer layer, (b) parsing the cache manifest by 
C<parse_byte_string> or C<parse_char_string> raises no error
with level C<m> or C<s>, and (c) checking the cache manifest by
C<check_manifest> raises no error with level C<m> or C<s>.

=back

=head1 MANIFEST DATA STRUCTURE

If I<$m> is in manifest data structure, I<$m> is a reference to
the array with three items: I<$explicit_uris>, I<$fallback_uris>,
and I<$online_whitelist>.

I<$explicit_uris> is a reference to the array, which
contains zero or more strings.  The strings are IRI references
of the explicit entries.

I<$fallback_uris> is a reference to the hash, which
contains zero or more mappings of strings (keys) to strings (values).
The keys are IRI references of the oppotunistic caching namespaces.
The values are IRI references of the fallback entries corresponding
to the oppotunistic caching namespaces.

I<$online_whitelist> is a reference to the array, which
contains zero or more strings.  The strings are IRI references
in the online whitelist.

=head1 DEPENDENCY

This module depends on L<Message::URI::URIReference>, which is
part of manakai.

=head1 SEE ALSO

Whatpm Error Types
<http://suika.fam.cx/gate/2005/sw/Whatpm%20Error%20Types>.

HTML5
<http://whatwg.org/html5>.

L<Message::URI::URIReference>
<http://suika.fam.cx/www/manakai-core/lib/Message/URI/URIReference.html>.

=head1 TODO

"Same scheme/host/port" comparison algorithm is not correctly implemented
yet.

=head1 AUTHOR

Wakaba <w@suika.fam.cx>

=head1 LICENSE

Copyright 2007 Wakaba <w@suika.fam.cx>

This library is free software; you can redistribute it
and/or modify it under the same terms as Perl itself.

=cut

# $Date: 2007/11/04 11:49:44 $