src/Cache/CacheUtilities.pm

#____________________________________________________________________ 
# File: CacheUtilities.pm
#____________________________________________________________________ 
#  
# Author: Shaun Ashby <Shaun.Ashby@cern.ch>
# Update: 2003-10-30 11:51:58+0100
# Revision: $Id: CacheUtilities.pm,v 1.6.2.5 2007/02/23 16:29:25 sashby Exp $ 
#
# Copyright: 2003 (C) Shaun Ashby
#
#--------------------------------------------------------------------

=head1 NAME

Cache::CacheUtilities - Utilities for reading and writing of cache files.

=head1 SYNOPSIS

Reading:

         print "Reading cached data","\n",if ($ENV{SCRAM_DEBUG});
         $cacheobject=&Cache::CacheUtilities::read($cachename);

Writing:
   
         &Cache::CacheUtilities::write($cacheobject,$cachename);

=head1 DESCRIPTION

Functions for reading and writing of cache files. This uses Storable::store() to
write out Perl data structures to files. For reading, the complete data structure
is read from the cache file using Storable::retrieve() which returns a variable
containing the original object.

=head1 METHODS

=over

=cut

package Cache::CacheUtilities;
require 5.004;

use IO::File;
use English;
use Exporter;

use Storable;

@ISA=qw(Exporter);

#
# Common functions for interacting with caches:
#

=item   C<read($cachefilename)>

Read the cache file $cachefilename and return a Perl object.

=cut

sub read()
   {
   my ($cachefilename) = @_;
   # Retrieve the cached object from the file:
   $cache = eval "retrieve(\"$cachefilename\")";
   die "Cache load error: ",$EVAL_ERROR,"\n", if ($EVAL_ERROR);
   return $cache;
   }

=item   C<write($cacheobject,$cachefilename)>

Dump the Perl object $cacheobject to a file $cachefilename.

=cut

sub write()
   {
   my ($cacheobject,$cachefilename) = @_;
   use File::Copy;
   print "[ CacheUtilities::write() ] Writing cache ",$cachefilename,"\n", if ($ENV{SCRAM_DEBUG});
   # Move the cache file to make a backup:
   move($cachefilename,$cachefilename.".bak") if ( -r $cachefilename);   
   # Use the store method of the Storable package to write out the object to a file:
   eval {
       store($cacheobject,$cachefilename);
   };
   
   die "Cache write error: ",$EVAL_ERROR,"\n", if ($EVAL_ERROR);
   
   # Change the permissions to -rw-r--r--:
   my $filemode = 0644;
   chmod $filemode, $cachefilename;

   return;
   }

1;


=back

=head1 AUTHOR/MAINTAINER

Shaun Ashby

=cut
Revision:	1.7.2.1
Committed:	Mon Feb 26 18:33:45 2007 UTC (18 years, 2 months ago) by sashby
Content type:	text/plain
Branch:	v103_with_xml
CVS Tags:	forV1_1_0, v103_xml_071106, V110p2, V110p1
Changes since 1.7:	+15 -26 lines
Log Message:	Ensure backwards compatibility for creating projects from XML based release.
#	User	Rev	Content
1	sashby	1.2	#____________________________________________________________________
2			# File: CacheUtilities.pm
3			#____________________________________________________________________
4			#
5			# Author: Shaun Ashby <Shaun.Ashby@cern.ch>
6			# Update: 2003-10-30 11:51:58+0100
7	sashby	1.7.2.1	# Revision: $Id: CacheUtilities.pm,v 1.6.2.5 2007/02/23 16:29:25 sashby Exp $
8	sashby	1.2	#
9			# Copyright: 2003 (C) Shaun Ashby
10			#
11			#--------------------------------------------------------------------
12	sashby	1.5
13			=head1 NAME
14
15			Cache::CacheUtilities - Utilities for reading and writing of cache files.
16
17			=head1 SYNOPSIS
18
19			Reading:
20
21			print "Reading cached data","\n",if ($ENV{SCRAM_DEBUG});
22			$cacheobject=&Cache::CacheUtilities::read($cachename);
23
24			Writing:
25
26			&Cache::CacheUtilities::write($cacheobject,$cachename);
27
28			=head1 DESCRIPTION
29
30	sashby	1.7.2.1	Functions for reading and writing of cache files. This uses Storable::store() to
31	sashby	1.5	write out Perl data structures to files. For reading, the complete data structure
32	sashby	1.7.2.1	is read from the cache file using Storable::retrieve() which returns a variable
33			containing the original object.
34	sashby	1.5
35			=head1 METHODS
36
37			=over
38
39			=cut
40
41	sashby	1.2	package Cache::CacheUtilities;
42			require 5.004;
43
44			use IO::File;
45			use English;
46			use Exporter;
47
48	sashby	1.7.2.1	use Storable;
49
50	sashby	1.2	@ISA=qw(Exporter);
51
52			#
53			# Common functions for interacting with caches:
54			#
55
56	sashby	1.5	=item C<read($cachefilename)>
57
58			Read the cache file $cachefilename and return a Perl object.
59
60			=cut
61
62	sashby	1.2	sub read()
63			{
64			my ($cachefilename) = @_;
65	sashby	1.7.2.1	# Retrieve the cached object from the file:
66			$cache = eval "retrieve(\"$cachefilename\")";
67	sashby	1.2	die "Cache load error: ",$EVAL_ERROR,"\n", if ($EVAL_ERROR);
68			return $cache;
69			}
70
71	sashby	1.6	=item C<write($cacheobject,$cachefilename)>
72	sashby	1.5
73			Dump the Perl object $cacheobject to a file $cachefilename.
74
75			=cut
76
77	sashby	1.2	sub write()
78			{
79			my ($cacheobject,$cachefilename) = @_;
80			use File::Copy;
81	sashby	1.7	print "[ CacheUtilities::write() ] Writing cache ",$cachefilename,"\n", if ($ENV{SCRAM_DEBUG});
82			# Move the cache file to make a backup:
83	sashby	1.2	move($cachefilename,$cachefilename.".bak") if ( -r $cachefilename);
84	sashby	1.7.2.1	# Use the store method of the Storable package to write out the object to a file:
85			eval {
86			store($cacheobject,$cachefilename);
87			};
88
89			die "Cache write error: ",$EVAL_ERROR,"\n", if ($EVAL_ERROR);
90
91	sashby	1.3	# Change the permissions to -rw-r--r--:
92			my $filemode = 0644;
93			chmod $filemode, $cachefilename;
94
95	sashby	1.2	return;
96			}
97
98			1;
99	sashby	1.5
100
101			=back
102
103			=head1 AUTHOR/MAINTAINER
104
105			Shaun Ashby
106
107			=cut