--- /dev/null
+#
+# Copyright (c) 1995-2000, Raphael Manfredi
+#
+# You may redistribute only under the same terms as Perl 5, as specified
+# in the README file that comes with the distribution.
+#
+
+require DynaLoader;
+require Exporter;
+package Storable; @ISA = qw(Exporter DynaLoader);
+
+@EXPORT = qw(store retrieve);
+@EXPORT_OK = qw(
+ nstore store_fd nstore_fd fd_retrieve
+ freeze nfreeze thaw
+ dclone
+ retrieve_fd
+ lock_store lock_nstore lock_retrieve
+ file_magic read_magic
+);
+
+use AutoLoader;
+use FileHandle;
+use vars qw($canonical $forgive_me $VERSION);
+
+$VERSION = '2.21';
+*AUTOLOAD = \&AutoLoader::AUTOLOAD; # Grrr...
+
+#
+# Use of Log::Agent is optional
+#
+
+{
+ local $SIG{__DIE__};
+ eval "use Log::Agent";
+}
+
+require Carp;
+
+#
+# They might miss :flock in Fcntl
+#
+
+BEGIN {
+ if (eval { require Fcntl; 1 } && exists $Fcntl::EXPORT_TAGS{'flock'}) {
+ Fcntl->import(':flock');
+ } else {
+ eval q{
+ sub LOCK_SH () {1}
+ sub LOCK_EX () {2}
+ };
+ }
+}
+
+sub CLONE {
+ # clone context under threads
+ Storable::init_perinterp();
+}
+
+# Can't Autoload cleanly as this clashes 8.3 with &retrieve
+sub retrieve_fd { &fd_retrieve } # Backward compatibility
+
+# By default restricted hashes are downgraded on earlier perls.
+
+$Storable::downgrade_restricted = 1;
+$Storable::accept_future_minor = 1;
+bootstrap Storable;
+1;
+__END__
+#
+# Use of Log::Agent is optional. If it hasn't imported these subs then
+# Autoloader will kindly supply our fallback implementation.
+#
+
+sub logcroak {
+ Carp::croak(@_);
+}
+
+sub logcarp {
+ Carp::carp(@_);
+}
+
+#
+# Determine whether locking is possible, but only when needed.
+#
+
+sub CAN_FLOCK; my $CAN_FLOCK; sub CAN_FLOCK {
+ return $CAN_FLOCK if defined $CAN_FLOCK;
+ require Config; import Config;
+ return $CAN_FLOCK =
+ $Config{'d_flock'} ||
+ $Config{'d_fcntl_can_lock'} ||
+ $Config{'d_lockf'};
+}
+
+sub show_file_magic {
+ print <<EOM;
+#
+# To recognize the data files of the Perl module Storable,
+# the following lines need to be added to the local magic(5) file,
+# usually either /usr/share/misc/magic or /etc/magic.
+#
+0 string perl-store perl Storable(v0.6) data
+>4 byte >0 (net-order %d)
+>>4 byte &01 (network-ordered)
+>>4 byte =3 (major 1)
+>>4 byte =2 (major 1)
+
+0 string pst0 perl Storable(v0.7) data
+>4 byte >0
+>>4 byte &01 (network-ordered)
+>>4 byte =5 (major 2)
+>>4 byte =4 (major 2)
+>>5 byte >0 (minor %d)
+EOM
+}
+
+sub file_magic {
+ my $file = shift;
+ my $fh = new FileHandle;
+ open($fh, "<". $file) || die "Can't open '$file': $!";
+ binmode($fh);
+ defined(sysread($fh, my $buf, 32)) || die "Can't read from '$file': $!";
+ close($fh);
+
+ $file = "./$file" unless $file; # ensure TRUE value
+
+ return read_magic($buf, $file);
+}
+
+sub read_magic {
+ my($buf, $file) = @_;
+ my %info;
+
+ my $buflen = length($buf);
+ my $magic;
+ if ($buf =~ s/^(pst0|perl-store)//) {
+ $magic = $1;
+ $info{file} = $file || 1;
+ }
+ else {
+ return undef if $file;
+ $magic = "";
+ }
+
+ return undef unless length($buf);
+
+ my $net_order;
+ if ($magic eq "perl-store" && ord(substr($buf, 0, 1)) > 1) {
+ $info{version} = -1;
+ $net_order = 0;
+ }
+ else {
+ $net_order = ord(substr($buf, 0, 1, ""));
+ my $major = $net_order >> 1;
+ return undef if $major > 4; # sanity (assuming we never go that high)
+ $info{major} = $major;
+ $net_order &= 0x01;
+ if ($major > 1) {
+ return undef unless length($buf);
+ my $minor = ord(substr($buf, 0, 1, ""));
+ $info{minor} = $minor;
+ $info{version} = "$major.$minor";
+ $info{version_nv} = sprintf "%d.%03d", $major, $minor;
+ }
+ else {
+ $info{version} = $major;
+ }
+ }
+ $info{version_nv} ||= $info{version};
+ $info{netorder} = $net_order;
+
+ unless ($net_order) {
+ return undef unless length($buf);
+ my $len = ord(substr($buf, 0, 1, ""));
+ return undef unless length($buf) >= $len;
+ return undef unless $len == 4 || $len == 8; # sanity
+ $info{byteorder} = substr($buf, 0, $len, "");
+ $info{intsize} = ord(substr($buf, 0, 1, ""));
+ $info{longsize} = ord(substr($buf, 0, 1, ""));
+ $info{ptrsize} = ord(substr($buf, 0, 1, ""));
+ if ($info{version_nv} >= 2.002) {
+ return undef unless length($buf);
+ $info{nvsize} = ord(substr($buf, 0, 1, ""));
+ }
+ }
+ $info{hdrsize} = $buflen - length($buf);
+
+ return \%info;
+}
+
+sub BIN_VERSION_NV {
+ sprintf "%d.%03d", BIN_MAJOR(), BIN_MINOR();
+}
+
+sub BIN_WRITE_VERSION_NV {
+ sprintf "%d.%03d", BIN_MAJOR(), BIN_WRITE_MINOR();
+}
+
+#
+# store
+#
+# Store target object hierarchy, identified by a reference to its root.
+# The stored object tree may later be retrieved to memory via retrieve.
+# Returns undef if an I/O error occurred, in which case the file is
+# removed.
+#
+sub store {
+ return _store(\&pstore, @_, 0);
+}
+
+#
+# nstore
+#
+# Same as store, but in network order.
+#
+sub nstore {
+ return _store(\&net_pstore, @_, 0);
+}
+
+#
+# lock_store
+#
+# Same as store, but flock the file first (advisory locking).
+#
+sub lock_store {
+ return _store(\&pstore, @_, 1);
+}
+
+#
+# lock_nstore
+#
+# Same as nstore, but flock the file first (advisory locking).
+#
+sub lock_nstore {
+ return _store(\&net_pstore, @_, 1);
+}
+
+# Internal store to file routine
+sub _store {
+ my $xsptr = shift;
+ my $self = shift;
+ my ($file, $use_locking) = @_;
+ logcroak "not a reference" unless ref($self);
+ logcroak "wrong argument number" unless @_ == 2; # No @foo in arglist
+ local *FILE;
+ if ($use_locking) {
+ open(FILE, ">>$file") || logcroak "can't write into $file: $!";
+ unless (&CAN_FLOCK) {
+ logcarp "Storable::lock_store: fcntl/flock emulation broken on $^O";
+ return undef;
+ }
+ flock(FILE, LOCK_EX) ||
+ logcroak "can't get exclusive lock on $file: $!";
+ truncate FILE, 0;
+ # Unlocking will happen when FILE is closed
+ } else {
+ open(FILE, ">$file") || logcroak "can't create $file: $!";
+ }
+ binmode FILE; # Archaic systems...
+ my $da = $@; # Don't mess if called from exception handler
+ my $ret;
+ # Call C routine nstore or pstore, depending on network order
+ eval { $ret = &$xsptr(*FILE, $self) };
+ close(FILE) or $ret = undef;
+ unlink($file) or warn "Can't unlink $file: $!\n" if $@ || !defined $ret;
+ logcroak $@ if $@ =~ s/\.?\n$/,/;
+ $@ = $da;
+ return $ret ? $ret : undef;
+}
+
+#
+# store_fd
+#
+# Same as store, but perform on an already opened file descriptor instead.
+# Returns undef if an I/O error occurred.
+#
+sub store_fd {
+ return _store_fd(\&pstore, @_);
+}
+
+#
+# nstore_fd
+#
+# Same as store_fd, but in network order.
+#
+sub nstore_fd {
+ my ($self, $file) = @_;
+ return _store_fd(\&net_pstore, @_);
+}
+
+# Internal store routine on opened file descriptor
+sub _store_fd {
+ my $xsptr = shift;
+ my $self = shift;
+ my ($file) = @_;
+ logcroak "not a reference" unless ref($self);
+ logcroak "too many arguments" unless @_ == 1; # No @foo in arglist
+ my $fd = fileno($file);
+ logcroak "not a valid file descriptor" unless defined $fd;
+ my $da = $@; # Don't mess if called from exception handler
+ my $ret;
+ # Call C routine nstore or pstore, depending on network order
+ eval { $ret = &$xsptr($file, $self) };
+ logcroak $@ if $@ =~ s/\.?\n$/,/;
+ local $\; print $file ''; # Autoflush the file if wanted
+ $@ = $da;
+ return $ret ? $ret : undef;
+}
+
+#
+# freeze
+#
+# Store oject and its hierarchy in memory and return a scalar
+# containing the result.
+#
+sub freeze {
+ _freeze(\&mstore, @_);
+}
+
+#
+# nfreeze
+#
+# Same as freeze but in network order.
+#
+sub nfreeze {
+ _freeze(\&net_mstore, @_);
+}
+
+# Internal freeze routine
+sub _freeze {
+ my $xsptr = shift;
+ my $self = shift;
+ logcroak "not a reference" unless ref($self);
+ logcroak "too many arguments" unless @_ == 0; # No @foo in arglist
+ my $da = $@; # Don't mess if called from exception handler
+ my $ret;
+ # Call C routine mstore or net_mstore, depending on network order
+ eval { $ret = &$xsptr($self) };
+ logcroak $@ if $@ =~ s/\.?\n$/,/;
+ $@ = $da;
+ return $ret ? $ret : undef;
+}
+
+#
+# retrieve
+#
+# Retrieve object hierarchy from disk, returning a reference to the root
+# object of that tree.
+#
+sub retrieve {
+ _retrieve($_[0], 0);
+}
+
+#
+# lock_retrieve
+#
+# Same as retrieve, but with advisory locking.
+#
+sub lock_retrieve {
+ _retrieve($_[0], 1);
+}
+
+# Internal retrieve routine
+sub _retrieve {
+ my ($file, $use_locking) = @_;
+ local *FILE;
+ open(FILE, $file) || logcroak "can't open $file: $!";
+ binmode FILE; # Archaic systems...
+ my $self;
+ my $da = $@; # Could be from exception handler
+ if ($use_locking) {
+ unless (&CAN_FLOCK) {
+ logcarp "Storable::lock_store: fcntl/flock emulation broken on $^O";
+ return undef;
+ }
+ flock(FILE, LOCK_SH) || logcroak "can't get shared lock on $file: $!";
+ # Unlocking will happen when FILE is closed
+ }
+ eval { $self = pretrieve(*FILE) }; # Call C routine
+ close(FILE);
+ logcroak $@ if $@ =~ s/\.?\n$/,/;
+ $@ = $da;
+ return $self;
+}
+
+#
+# fd_retrieve
+#
+# Same as retrieve, but perform from an already opened file descriptor instead.
+#
+sub fd_retrieve {
+ my ($file) = @_;
+ my $fd = fileno($file);
+ logcroak "not a valid file descriptor" unless defined $fd;
+ my $self;
+ my $da = $@; # Could be from exception handler
+ eval { $self = pretrieve($file) }; # Call C routine
+ logcroak $@ if $@ =~ s/\.?\n$/,/;
+ $@ = $da;
+ return $self;
+}
+
+#
+# thaw
+#
+# Recreate objects in memory from an existing frozen image created
+# by freeze. If the frozen image passed is undef, return undef.
+#
+sub thaw {
+ my ($frozen) = @_;
+ return undef unless defined $frozen;
+ my $self;
+ my $da = $@; # Could be from exception handler
+ eval { $self = mretrieve($frozen) }; # Call C routine
+ logcroak $@ if $@ =~ s/\.?\n$/,/;
+ $@ = $da;
+ return $self;
+}
+
+1;
+__END__
+
+=head1 NAME
+
+Storable - persistence for Perl data structures
+
+=head1 SYNOPSIS
+
+ use Storable;
+ store \%table, 'file';
+ $hashref = retrieve('file');
+
+ use Storable qw(nstore store_fd nstore_fd freeze thaw dclone);
+
+ # Network order
+ nstore \%table, 'file';
+ $hashref = retrieve('file'); # There is NO nretrieve()
+
+ # Storing to and retrieving from an already opened file
+ store_fd \@array, \*STDOUT;
+ nstore_fd \%table, \*STDOUT;
+ $aryref = fd_retrieve(\*SOCKET);
+ $hashref = fd_retrieve(\*SOCKET);
+
+ # Serializing to memory
+ $serialized = freeze \%table;
+ %table_clone = %{ thaw($serialized) };
+
+ # Deep (recursive) cloning
+ $cloneref = dclone($ref);
+
+ # Advisory locking
+ use Storable qw(lock_store lock_nstore lock_retrieve)
+ lock_store \%table, 'file';
+ lock_nstore \%table, 'file';
+ $hashref = lock_retrieve('file');
+
+=head1 DESCRIPTION
+
+The Storable package brings persistence to your Perl data structures
+containing SCALAR, ARRAY, HASH or REF objects, i.e. anything that can be
+conveniently stored to disk and retrieved at a later time.
+
+It can be used in the regular procedural way by calling C<store> with
+a reference to the object to be stored, along with the file name where
+the image should be written.
+
+The routine returns C<undef> for I/O problems or other internal error,
+a true value otherwise. Serious errors are propagated as a C<die> exception.
+
+To retrieve data stored to disk, use C<retrieve> with a file name.
+The objects stored into that file are recreated into memory for you,
+and a I<reference> to the root object is returned. In case an I/O error
+occurs while reading, C<undef> is returned instead. Other serious
+errors are propagated via C<die>.
+
+Since storage is performed recursively, you might want to stuff references
+to objects that share a lot of common data into a single array or hash
+table, and then store that object. That way, when you retrieve back the
+whole thing, the objects will continue to share what they originally shared.
+
+At the cost of a slight header overhead, you may store to an already
+opened file descriptor using the C<store_fd> routine, and retrieve
+from a file via C<fd_retrieve>. Those names aren't imported by default,
+so you will have to do that explicitly if you need those routines.
+The file descriptor you supply must be already opened, for read
+if you're going to retrieve and for write if you wish to store.
+
+ store_fd(\%table, *STDOUT) || die "can't store to stdout\n";
+ $hashref = fd_retrieve(*STDIN);
+
+You can also store data in network order to allow easy sharing across
+multiple platforms, or when storing on a socket known to be remotely
+connected. The routines to call have an initial C<n> prefix for I<network>,
+as in C<nstore> and C<nstore_fd>. At retrieval time, your data will be
+correctly restored so you don't have to know whether you're restoring
+from native or network ordered data. Double values are stored stringified
+to ensure portability as well, at the slight risk of loosing some precision
+in the last decimals.
+
+When using C<fd_retrieve>, objects are retrieved in sequence, one
+object (i.e. one recursive tree) per associated C<store_fd>.
+
+If you're more from the object-oriented camp, you can inherit from
+Storable and directly store your objects by invoking C<store> as
+a method. The fact that the root of the to-be-stored tree is a
+blessed reference (i.e. an object) is special-cased so that the
+retrieve does not provide a reference to that object but rather the
+blessed object reference itself. (Otherwise, you'd get a reference
+to that blessed object).
+
+=head1 MEMORY STORE
+
+The Storable engine can also store data into a Perl scalar instead, to
+later retrieve them. This is mainly used to freeze a complex structure in
+some safe compact memory place (where it can possibly be sent to another
+process via some IPC, since freezing the structure also serializes it in
+effect). Later on, and maybe somewhere else, you can thaw the Perl scalar
+out and recreate the original complex structure in memory.
+
+Surprisingly, the routines to be called are named C<freeze> and C<thaw>.
+If you wish to send out the frozen scalar to another machine, use
+C<nfreeze> instead to get a portable image.
+
+Note that freezing an object structure and immediately thawing it
+actually achieves a deep cloning of that structure:
+
+ dclone(.) = thaw(freeze(.))
+
+Storable provides you with a C<dclone> interface which does not create
+that intermediary scalar but instead freezes the structure in some
+internal memory space and then immediately thaws it out.
+
+=head1 ADVISORY LOCKING
+
+The C<lock_store> and C<lock_nstore> routine are equivalent to
+C<store> and C<nstore>, except that they get an exclusive lock on
+the file before writing. Likewise, C<lock_retrieve> does the same
+as C<retrieve>, but also gets a shared lock on the file before reading.
+
+As with any advisory locking scheme, the protection only works if you
+systematically use C<lock_store> and C<lock_retrieve>. If one side of
+your application uses C<store> whilst the other uses C<lock_retrieve>,
+you will get no protection at all.
+
+The internal advisory locking is implemented using Perl's flock()
+routine. If your system does not support any form of flock(), or if
+you share your files across NFS, you might wish to use other forms
+of locking by using modules such as LockFile::Simple which lock a
+file using a filesystem entry, instead of locking the file descriptor.
+
+=head1 SPEED
+
+The heart of Storable is written in C for decent speed. Extra low-level
+optimizations have been made when manipulating perl internals, to
+sacrifice encapsulation for the benefit of greater speed.
+
+=head1 CANONICAL REPRESENTATION
+
+Normally, Storable stores elements of hashes in the order they are
+stored internally by Perl, i.e. pseudo-randomly. If you set
+C<$Storable::canonical> to some C<TRUE> value, Storable will store
+hashes with the elements sorted by their key. This allows you to
+compare data structures by comparing their frozen representations (or
+even the compressed frozen representations), which can be useful for
+creating lookup tables for complicated queries.
+
+Canonical order does not imply network order; those are two orthogonal
+settings.
+
+=head1 CODE REFERENCES
+
+Since Storable version 2.05, CODE references may be serialized with
+the help of L<B::Deparse>. To enable this feature, set
+C<$Storable::Deparse> to a true value. To enable deserialization,
+C<$Storable::Eval> should be set to a true value. Be aware that
+deserialization is done through C<eval>, which is dangerous if the
+Storable file contains malicious data. You can set C<$Storable::Eval>
+to a subroutine reference which would be used instead of C<eval>. See
+below for an example using a L<Safe> compartment for deserialization
+of CODE references.
+
+If C<$Storable::Deparse> and/or C<$Storable::Eval> are set to false
+values, then the value of C<$Storable::forgive_me> (see below) is
+respected while serializing and deserializing.
+
+=head1 FORWARD COMPATIBILITY
+
+This release of Storable can be used on a newer version of Perl to
+serialize data which is not supported by earlier Perls. By default,
+Storable will attempt to do the right thing, by C<croak()>ing if it
+encounters data that it cannot deserialize. However, the defaults
+can be changed as follows:
+
+=over 4
+
+=item utf8 data
+
+Perl 5.6 added support for Unicode characters with code points > 255,
+and Perl 5.8 has full support for Unicode characters in hash keys.
+Perl internally encodes strings with these characters using utf8, and
+Storable serializes them as utf8. By default, if an older version of
+Perl encounters a utf8 value it cannot represent, it will C<croak()>.
+To change this behaviour so that Storable deserializes utf8 encoded
+values as the string of bytes (effectively dropping the I<is_utf8> flag)
+set C<$Storable::drop_utf8> to some C<TRUE> value. This is a form of
+data loss, because with C<$drop_utf8> true, it becomes impossible to tell
+whether the original data was the Unicode string, or a series of bytes
+that happen to be valid utf8.
+
+=item restricted hashes
+
+Perl 5.8 adds support for restricted hashes, which have keys
+restricted to a given set, and can have values locked to be read only.
+By default, when Storable encounters a restricted hash on a perl
+that doesn't support them, it will deserialize it as a normal hash,
+silently discarding any placeholder keys and leaving the keys and
+all values unlocked. To make Storable C<croak()> instead, set
+C<$Storable::downgrade_restricted> to a C<FALSE> value. To restore
+the default set it back to some C<TRUE> value.
+
+=item files from future versions of Storable
+
+Earlier versions of Storable would immediately croak if they encountered
+a file with a higher internal version number than the reading Storable
+knew about. Internal version numbers are increased each time new data
+types (such as restricted hashes) are added to the vocabulary of the file
+format. This meant that a newer Storable module had no way of writing a
+file readable by an older Storable, even if the writer didn't store newer
+data types.
+
+This version of Storable will defer croaking until it encounters a data
+type in the file that it does not recognize. This means that it will
+continue to read files generated by newer Storable modules which are careful
+in what they write out, making it easier to upgrade Storable modules in a
+mixed environment.
+
+The old behaviour of immediate croaking can be re-instated by setting
+C<$Storable::accept_future_minor> to some C<FALSE> value.
+
+=back
+
+All these variables have no effect on a newer Perl which supports the
+relevant feature.
+
+=head1 ERROR REPORTING
+
+Storable uses the "exception" paradigm, in that it does not try to workaround
+failures: if something bad happens, an exception is generated from the
+caller's perspective (see L<Carp> and C<croak()>). Use eval {} to trap
+those exceptions.
+
+When Storable croaks, it tries to report the error via the C<logcroak()>
+routine from the C<Log::Agent> package, if it is available.
+
+Normal errors are reported by having store() or retrieve() return C<undef>.
+Such errors are usually I/O errors (or truncated stream errors at retrieval).
+
+=head1 WIZARDS ONLY
+
+=head2 Hooks
+
+Any class may define hooks that will be called during the serialization
+and deserialization process on objects that are instances of that class.
+Those hooks can redefine the way serialization is performed (and therefore,
+how the symmetrical deserialization should be conducted).
+
+Since we said earlier:
+
+ dclone(.) = thaw(freeze(.))
+
+everything we say about hooks should also hold for deep cloning. However,
+hooks get to know whether the operation is a mere serialization, or a cloning.
+
+Therefore, when serializing hooks are involved,
+
+ dclone(.) <> thaw(freeze(.))
+
+Well, you could keep them in sync, but there's no guarantee it will always
+hold on classes somebody else wrote. Besides, there is little to gain in
+doing so: a serializing hook could keep only one attribute of an object,
+which is probably not what should happen during a deep cloning of that
+same object.
+
+Here is the hooking interface:
+
+=over 4
+
+=item C<STORABLE_freeze> I<obj>, I<cloning>
+
+The serializing hook, called on the object during serialization. It can be
+inherited, or defined in the class itself, like any other method.
+
+Arguments: I<obj> is the object to serialize, I<cloning> is a flag indicating
+whether we're in a dclone() or a regular serialization via store() or freeze().
+
+Returned value: A LIST C<($serialized, $ref1, $ref2, ...)> where $serialized
+is the serialized form to be used, and the optional $ref1, $ref2, etc... are
+extra references that you wish to let the Storable engine serialize.
+
+At deserialization time, you will be given back the same LIST, but all the
+extra references will be pointing into the deserialized structure.
+
+The B<first time> the hook is hit in a serialization flow, you may have it
+return an empty list. That will signal the Storable engine to further
+discard that hook for this class and to therefore revert to the default
+serialization of the underlying Perl data. The hook will again be normally
+processed in the next serialization.
+
+Unless you know better, serializing hook should always say:
+
+ sub STORABLE_freeze {
+ my ($self, $cloning) = @_;
+ return if $cloning; # Regular default serialization
+ ....
+ }
+
+in order to keep reasonable dclone() semantics.
+
+=item C<STORABLE_thaw> I<obj>, I<cloning>, I<serialized>, ...
+
+The deserializing hook called on the object during deserialization.
+But wait: if we're deserializing, there's no object yet... right?
+
+Wrong: the Storable engine creates an empty one for you. If you know Eiffel,
+you can view C<STORABLE_thaw> as an alternate creation routine.
+
+This means the hook can be inherited like any other method, and that
+I<obj> is your blessed reference for this particular instance.
+
+The other arguments should look familiar if you know C<STORABLE_freeze>:
+I<cloning> is true when we're part of a deep clone operation, I<serialized>
+is the serialized string you returned to the engine in C<STORABLE_freeze>,
+and there may be an optional list of references, in the same order you gave
+them at serialization time, pointing to the deserialized objects (which
+have been processed courtesy of the Storable engine).
+
+When the Storable engine does not find any C<STORABLE_thaw> hook routine,
+it tries to load the class by requiring the package dynamically (using
+the blessed package name), and then re-attempts the lookup. If at that
+time the hook cannot be located, the engine croaks. Note that this mechanism
+will fail if you define several classes in the same file, but L<perlmod>
+warned you.
+
+It is up to you to use this information to populate I<obj> the way you want.
+
+Returned value: none.
+
+=item C<STORABLE_attach> I<class>, I<cloning>, I<serialized>
+
+While C<STORABLE_freeze> and C<STORABLE_thaw> are useful for classes where
+each instance is independent, this mechanism has difficulty (or is
+incompatible) with objects that exist as common process-level or
+system-level resources, such as singleton objects, database pools, caches
+or memoized objects.
+
+The alternative C<STORABLE_attach> method provides a solution for these
+shared objects. Instead of C<STORABLE_freeze> --E<gt> C<STORABLE_thaw>,
+you implement C<STORABLE_freeze> --E<gt> C<STORABLE_attach> instead.
+
+Arguments: I<class> is the class we are attaching to, I<cloning> is a flag
+indicating whether we're in a dclone() or a regular de-serialization via
+thaw(), and I<serialized> is the stored string for the resource object.
+
+Because these resource objects are considered to be owned by the entire
+process/system, and not the "property" of whatever is being serialized,
+no references underneath the object should be included in the serialized
+string. Thus, in any class that implements C<STORABLE_attach>, the
+C<STORABLE_freeze> method cannot return any references, and C<Storable>
+will throw an error if C<STORABLE_freeze> tries to return references.
+
+All information required to "attach" back to the shared resource object
+B<must> be contained B<only> in the C<STORABLE_freeze> return string.
+Otherwise, C<STORABLE_freeze> behaves as normal for C<STORABLE_attach>
+classes.
+
+Because C<STORABLE_attach> is passed the class (rather than an object),
+it also returns the object directly, rather than modifying the passed
+object.
+
+Returned value: object of type C<class>
+
+=back
+
+=head2 Predicates
+
+Predicates are not exportable. They must be called by explicitly prefixing
+them with the Storable package name.
+
+=over 4
+
+=item C<Storable::last_op_in_netorder>
+
+The C<Storable::last_op_in_netorder()> predicate will tell you whether
+network order was used in the last store or retrieve operation. If you
+don't know how to use this, just forget about it.
+
+=item C<Storable::is_storing>
+
+Returns true if within a store operation (via STORABLE_freeze hook).
+
+=item C<Storable::is_retrieving>
+
+Returns true if within a retrieve operation (via STORABLE_thaw hook).
+
+=back
+
+=head2 Recursion
+
+With hooks comes the ability to recurse back to the Storable engine.
+Indeed, hooks are regular Perl code, and Storable is convenient when
+it comes to serializing and deserializing things, so why not use it
+to handle the serialization string?
+
+There are a few things you need to know, however:
+
+=over 4
+
+=item *
+
+You can create endless loops if the things you serialize via freeze()
+(for instance) point back to the object we're trying to serialize in
+the hook.
+
+=item *
+
+Shared references among objects will not stay shared: if we're serializing
+the list of object [A, C] where both object A and C refer to the SAME object
+B, and if there is a serializing hook in A that says freeze(B), then when
+deserializing, we'll get [A', C'] where A' refers to B', but C' refers to D,
+a deep clone of B'. The topology was not preserved.
+
+=back
+
+That's why C<STORABLE_freeze> lets you provide a list of references
+to serialize. The engine guarantees that those will be serialized in the
+same context as the other objects, and therefore that shared objects will
+stay shared.
+
+In the above [A, C] example, the C<STORABLE_freeze> hook could return:
+
+ ("something", $self->{B})
+
+and the B part would be serialized by the engine. In C<STORABLE_thaw>, you
+would get back the reference to the B' object, deserialized for you.
+
+Therefore, recursion should normally be avoided, but is nonetheless supported.
+
+=head2 Deep Cloning
+
+There is a Clone module available on CPAN which implements deep cloning
+natively, i.e. without freezing to memory and thawing the result. It is
+aimed to replace Storable's dclone() some day. However, it does not currently
+support Storable hooks to redefine the way deep cloning is performed.
+
+=head1 Storable magic
+
+Yes, there's a lot of that :-) But more precisely, in UNIX systems
+there's a utility called C<file>, which recognizes data files based on
+their contents (usually their first few bytes). For this to work,
+a certain file called F<magic> needs to taught about the I<signature>
+of the data. Where that configuration file lives depends on the UNIX
+flavour; often it's something like F</usr/share/misc/magic> or
+F</etc/magic>. Your system administrator needs to do the updating of
+the F<magic> file. The necessary signature information is output to
+STDOUT by invoking Storable::show_file_magic(). Note that the GNU
+implementation of the C<file> utility, version 3.38 or later,
+is expected to contain support for recognising Storable files
+out-of-the-box, in addition to other kinds of Perl files.
+
+You can also use the following functions to extract the file header
+information from Storable images:
+
+=over
+
+=item $info = Storable::file_magic( $filename )
+
+If the given file is a Storable image return a hash describing it. If
+the file is readable, but not a Storable image return C<undef>. If
+the file does not exist or is unreadable then croak.
+
+The hash returned has the following elements:
+
+=over
+
+=item C<version>
+
+This returns the file format version. It is a string like "2.7".
+
+Note that this version number is not the same as the version number of
+the Storable module itself. For instance Storable v0.7 create files
+in format v2.0 and Storable v2.15 create files in format v2.7. The
+file format version number only increment when additional features
+that would confuse older versions of the module are added.
+
+Files older than v2.0 will have the one of the version numbers "-1",
+"0" or "1". No minor number was used at that time.
+
+=item C<version_nv>
+
+This returns the file format version as number. It is a string like
+"2.007". This value is suitable for numeric comparisons.
+
+The constant function C<Storable::BIN_VERSION_NV> returns a comparable
+number that represent the highest file version number that this
+version of Storable fully support (but see discussion of
+C<$Storable::accept_future_minor> above). The constant
+C<Storable::BIN_WRITE_VERSION_NV> function returns what file version
+is written and might be less than C<Storable::BIN_VERSION_NV> in some
+configuations.
+
+=item C<major>, C<minor>
+
+This also returns the file format version. If the version is "2.7"
+then major would be 2 and minor would be 7. The minor element is
+missing for when major is less than 2.
+
+=item C<hdrsize>
+
+The is the number of bytes that the Storable header occupies.
+
+=item C<netorder>
+
+This is TRUE if the image store data in network order. This means
+that it was created with nstore() or similar.
+
+=item C<byteorder>
+
+This is only present when C<netorder> is FALSE. It is the
+$Config{byteorder} string of the perl that created this image. It is
+a string like "1234" (32 bit little endian) or "87654321" (64 bit big
+endian). This must match the current perl for the image to be
+readable by Storable.
+
+=item C<intsize>, C<longsize>, C<ptrsize>, C<nvsize>
+
+These are only present when C<netorder> is FALSE. These are the sizes of
+various C datatypes of the perl that created this image. These must
+match the current perl for the image to be readable by Storable.
+
+The C<nvsize> element is only present for file format v2.2 and
+higher.
+
+=item C<file>
+
+The name of the file.
+
+=back
+
+=item $info = Storable::read_magic( $buffer )
+
+=item $info = Storable::read_magic( $buffer, $must_be_file )
+
+The $buffer should be a Storable image or the first few bytes of it.
+If $buffer starts with a Storable header, then a hash describing the
+image is returned, otherwise C<undef> is returned.
+
+The hash has the same structure as the one returned by
+Storable::file_magic(). The C<file> element is true if the image is a
+file image.
+
+If the $must_be_file argument is provided and is TRUE, then return
+C<undef> unless the image looks like it belongs to a file dump.
+
+The maximum size of a Storable header is currently 21 bytes. If the
+provided $buffer is only the first part of a Storable image it should
+at least be this long to ensure that read_magic() will recognize it as
+such.
+
+=back
+
+=head1 EXAMPLES
+
+Here are some code samples showing a possible usage of Storable:
+
+ use Storable qw(store retrieve freeze thaw dclone);
+
+ %color = ('Blue' => 0.1, 'Red' => 0.8, 'Black' => 0, 'White' => 1);
+
+ store(\%color, 'mycolors') or die "Can't store %a in mycolors!\n";
+
+ $colref = retrieve('mycolors');
+ die "Unable to retrieve from mycolors!\n" unless defined $colref;
+ printf "Blue is still %lf\n", $colref->{'Blue'};
+
+ $colref2 = dclone(\%color);
+
+ $str = freeze(\%color);
+ printf "Serialization of %%color is %d bytes long.\n", length($str);
+ $colref3 = thaw($str);
+
+which prints (on my machine):
+
+ Blue is still 0.100000
+ Serialization of %color is 102 bytes long.
+
+Serialization of CODE references and deserialization in a safe
+compartment:
+
+=for example begin
+
+ use Storable qw(freeze thaw);
+ use Safe;
+ use strict;
+ my $safe = new Safe;
+ # because of opcodes used in "use strict":
+ $safe->permit(qw(:default require));
+ local $Storable::Deparse = 1;
+ local $Storable::Eval = sub { $safe->reval($_[0]) };
+ my $serialized = freeze(sub { 42 });
+ my $code = thaw($serialized);
+ $code->() == 42;
+
+=for example end
+
+=for example_testing
+ is( $code->(), 42 );
+
+=head1 WARNING
+
+If you're using references as keys within your hash tables, you're bound
+to be disappointed when retrieving your data. Indeed, Perl stringifies
+references used as hash table keys. If you later wish to access the
+items via another reference stringification (i.e. using the same
+reference that was used for the key originally to record the value into
+the hash table), it will work because both references stringify to the
+same string.
+
+It won't work across a sequence of C<store> and C<retrieve> operations,
+however, because the addresses in the retrieved objects, which are
+part of the stringified references, will probably differ from the
+original addresses. The topology of your structure is preserved,
+but not hidden semantics like those.
+
+On platforms where it matters, be sure to call C<binmode()> on the
+descriptors that you pass to Storable functions.
+
+Storing data canonically that contains large hashes can be
+significantly slower than storing the same data normally, as
+temporary arrays to hold the keys for each hash have to be allocated,
+populated, sorted and freed. Some tests have shown a halving of the
+speed of storing -- the exact penalty will depend on the complexity of
+your data. There is no slowdown on retrieval.
+
+=head1 BUGS
+
+You can't store GLOB, FORMLINE, etc.... If you can define semantics
+for those operations, feel free to enhance Storable so that it can
+deal with them.
+
+The store functions will C<croak> if they run into such references
+unless you set C<$Storable::forgive_me> to some C<TRUE> value. In that
+case, the fatal message is turned in a warning and some
+meaningless string is stored instead.
+
+Setting C<$Storable::canonical> may not yield frozen strings that
+compare equal due to possible stringification of numbers. When the
+string version of a scalar exists, it is the form stored; therefore,
+if you happen to use your numbers as strings between two freezing
+operations on the same data structures, you will get different
+results.
+
+When storing doubles in network order, their value is stored as text.
+However, you should also not expect non-numeric floating-point values
+such as infinity and "not a number" to pass successfully through a
+nstore()/retrieve() pair.
+
+As Storable neither knows nor cares about character sets (although it
+does know that characters may be more than eight bits wide), any difference
+in the interpretation of character codes between a host and a target
+system is your problem. In particular, if host and target use different
+code points to represent the characters used in the text representation
+of floating-point numbers, you will not be able be able to exchange
+floating-point data, even with nstore().
+
+C<Storable::drop_utf8> is a blunt tool. There is no facility either to
+return B<all> strings as utf8 sequences, or to attempt to convert utf8
+data back to 8 bit and C<croak()> if the conversion fails.
+
+Prior to Storable 2.01, no distinction was made between signed and
+unsigned integers on storing. By default Storable prefers to store a
+scalars string representation (if it has one) so this would only cause
+problems when storing large unsigned integers that had never been converted
+to string or floating point. In other words values that had been generated
+by integer operations such as logic ops and then not used in any string or
+arithmetic context before storing.
+
+=head2 64 bit data in perl 5.6.0 and 5.6.1
+
+This section only applies to you if you have existing data written out
+by Storable 2.02 or earlier on perl 5.6.0 or 5.6.1 on Unix or Linux which
+has been configured with 64 bit integer support (not the default)
+If you got a precompiled perl, rather than running Configure to build
+your own perl from source, then it almost certainly does not affect you,
+and you can stop reading now (unless you're curious). If you're using perl
+on Windows it does not affect you.
+
+Storable writes a file header which contains the sizes of various C
+language types for the C compiler that built Storable (when not writing in
+network order), and will refuse to load files written by a Storable not
+on the same (or compatible) architecture. This check and a check on
+machine byteorder is needed because the size of various fields in the file
+are given by the sizes of the C language types, and so files written on
+different architectures are incompatible. This is done for increased speed.
+(When writing in network order, all fields are written out as standard
+lengths, which allows full interworking, but takes longer to read and write)
+
+Perl 5.6.x introduced the ability to optional configure the perl interpreter
+to use C's C<long long> type to allow scalars to store 64 bit integers on 32
+bit systems. However, due to the way the Perl configuration system
+generated the C configuration files on non-Windows platforms, and the way
+Storable generates its header, nothing in the Storable file header reflected
+whether the perl writing was using 32 or 64 bit integers, despite the fact
+that Storable was storing some data differently in the file. Hence Storable
+running on perl with 64 bit integers will read the header from a file
+written by a 32 bit perl, not realise that the data is actually in a subtly
+incompatible format, and then go horribly wrong (possibly crashing) if it
+encountered a stored integer. This is a design failure.
+
+Storable has now been changed to write out and read in a file header with
+information about the size of integers. It's impossible to detect whether
+an old file being read in was written with 32 or 64 bit integers (they have
+the same header) so it's impossible to automatically switch to a correct
+backwards compatibility mode. Hence this Storable defaults to the new,
+correct behaviour.
+
+What this means is that if you have data written by Storable 1.x running
+on perl 5.6.0 or 5.6.1 configured with 64 bit integers on Unix or Linux
+then by default this Storable will refuse to read it, giving the error
+I<Byte order is not compatible>. If you have such data then you you
+should set C<$Storable::interwork_56_64bit> to a true value to make this
+Storable read and write files with the old header. You should also
+migrate your data, or any older perl you are communicating with, to this
+current version of Storable.
+
+If you don't have data written with specific configuration of perl described
+above, then you do not and should not do anything. Don't set the flag -
+not only will Storable on an identically configured perl refuse to load them,
+but Storable a differently configured perl will load them believing them
+to be correct for it, and then may well fail or crash part way through
+reading them.
+
+=head1 CREDITS
+
+Thank you to (in chronological order):
+
+ Jarkko Hietaniemi <jhi@iki.fi>
+ Ulrich Pfeifer <pfeifer@charly.informatik.uni-dortmund.de>
+ Benjamin A. Holzman <bah@ecnvantage.com>
+ Andrew Ford <A.Ford@ford-mason.co.uk>
+ Gisle Aas <gisle@aas.no>
+ Jeff Gresham <gresham_jeffrey@jpmorgan.com>
+ Murray Nesbitt <murray@activestate.com>
+ Marc Lehmann <pcg@opengroup.org>
+ Justin Banks <justinb@wamnet.com>
+ Jarkko Hietaniemi <jhi@iki.fi> (AGAIN, as perl 5.7.0 Pumpkin!)
+ Salvador Ortiz Garcia <sog@msg.com.mx>
+ Dominic Dunlop <domo@computer.org>
+ Erik Haugan <erik@solbors.no>
+
+for their bug reports, suggestions and contributions.
+
+Benjamin Holzman contributed the tied variable support, Andrew Ford
+contributed the canonical order for hashes, and Gisle Aas fixed
+a few misunderstandings of mine regarding the perl internals,
+and optimized the emission of "tags" in the output streams by
+simply counting the objects instead of tagging them (leading to
+a binary incompatibility for the Storable image starting at version
+0.6--older images are, of course, still properly understood).
+Murray Nesbitt made Storable thread-safe. Marc Lehmann added overloading
+and references to tied items support.
+
+=head1 AUTHOR
+
+Storable was written by Raphael Manfredi F<E<lt>Raphael_Manfredi@pobox.comE<gt>>
+Maintenance is now done by the perl5-porters F<E<lt>perl5-porters@perl.orgE<gt>>
+
+Please e-mail us with problems, bug fixes, comments and complaints,
+although if you have compliments you should send them to Raphael.
+Please don't e-mail Raphael with problems, as he no longer works on
+Storable, and your message will be delayed while he forwards it to us.
+
+=head1 SEE ALSO
+
+L<Clone>.
+
+=cut
projects / catagits/Gitalist.git / blobdiff