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#============================================================= -*-Perl-*-
#
# Template::Provider
#
# DESCRIPTION
#   This module implements a class which handles the loading, compiling
#   and caching of templates.  Multiple Template::Provider objects can
#   be stacked and queried in turn to effect a Chain-of-Command between
#   them.  A provider will attempt to return the requested template,
#   an error (STATUS_ERROR) or decline to provide the template
#   (STATUS_DECLINE), allowing subsequent providers to attempt to
#   deliver it.   See 'Design Patterns' for further details.
#
# AUTHORS
#   Andy Wardley <abw@wardley.org>
#
#   Refactored by Bill Moseley for v2.19 to add negative caching (i.e.
#   tracking templates that are NOTFOUND so that we can decline quickly)
#   and to provide better support for subclassing the provider.
#
# COPYRIGHT
#   Copyright (C) 1996-2022 Andy Wardley.  All Rights Reserved.
#
#   This module is free software; you can redistribute it and/or
#   modify it under the same terms as Perl itself.
#
# WARNING:
#   This code is ugly and contorted and is being totally re-written for TT3.
#   In particular, we'll be throwing errors rather than messing around
#   returning (value, status) pairs.  With the benefit of hindsight, that
#   was a really bad design decision on my part. I deserve to be knocked
#   to the ground and kicked around a bit by hoards of angry TT developers
#   for that one.  Bill's refactoring has made the module easier to subclass,
#   (so you can ease off the kicking now), but it really needs to be totally
#   redesigned and rebuilt from the ground up along with the bits of TT that
#   use it.                                           -- abw 2007/04/27
#============================================================================

package Template::Provider;

use strict;
use warnings;
use base 'Template::Base';
use Template::Config;
use Template::Constants;
use Template::Document;
use File::Basename;
use File::Spec;

use constant PREV    => 0;
use constant NAME    => 1;   # template name -- indexed by this name in LOOKUP
use constant DATA    => 2;   # Compiled template
use constant LOAD    => 3;   # mtime of template
use constant NEXT    => 4;   # link to next item in cache linked list
use constant STAT    => 5;   # Time last stat()ed
use constant MSWin32 => $^O eq 'MSWin32';

our $VERSION = '3.106';
our $DEBUG   = 0 unless defined $DEBUG;
our $ERROR   = '';

# name of document class
our $DOCUMENT = 'Template::Document' unless defined $DOCUMENT;

# maximum time between performing stat() on file to check staleness
our $STAT_TTL = 1 unless defined $STAT_TTL;

# maximum number of directories in an INCLUDE_PATH, to prevent runaways
our $MAX_DIRS = 64 unless defined $MAX_DIRS;

# UNICODE is supported in versions of Perl from 5.007 onwards
our $UNICODE = $] > 5.007 ? 1 : 0;

my $boms = [
    'UTF-8'    => "\x{ef}\x{bb}\x{bf}",
    'UTF-32BE' => "\x{0}\x{0}\x{fe}\x{ff}",
    'UTF-32LE' => "\x{ff}\x{fe}\x{0}\x{0}",
    'UTF-16BE' => "\x{fe}\x{ff}",
    'UTF-16LE' => "\x{ff}\x{fe}",
];

# regex to match relative paths
our $RELATIVE_PATH = qr[(?:^|/)\.+/];

#========================================================================
#                         -- PUBLIC METHODS --
#========================================================================

#------------------------------------------------------------------------
# fetch($name)