use warnings;
use strict;
use vars qw($VERSION $DEBUG %EXPORT_TAGS @EXPORT_OK @EXPORT);
-use base qw(Exporter);
+use Exporter qw(import);
BEGIN{
$VERSION = 1.00;
@EXPORT = ();
%EXPORT_TAGS = (util => [qw(getbugcomponent getbuglocation getlocationpath get_hashname),
- qw(appendfile buglog getparsedaddrs getmaintainers),
+ qw(appendfile overwritefile buglog getparsedaddrs getmaintainers),
+ qw(getsourcemaintainers getsourcemaintainers_reverse),
+ qw(bug_status),
qw(getmaintainers_reverse),
qw(getpseudodesc),
+ qw(package_maintainer),
+ qw(sort_versions),
+ qw(open_compressed_file),
+ ],
+ misc => [qw(make_list globify_scalar english_join checkpid),
+ qw(cleanup_eval_fail),
+ qw(hash_slice),
],
- misc => [qw(make_list globify_scalar)],
date => [qw(secs_to_english)],
quit => [qw(quit)],
- lock => [qw(filelock unfilelock lockpid)],
+ lock => [qw(filelock unfilelock lockpid simple_filelock simple_unlockfile)],
);
@EXPORT_OK = ();
- Exporter::export_ok_tags(qw(lock quit date util misc));
+ Exporter::export_ok_tags(keys %EXPORT_TAGS);
$EXPORT_TAGS{all} = [@EXPORT_OK];
}
#use Debbugs::Config qw(:globals);
use Carp;
+$Carp::Verbose = 1;
use Debbugs::Config qw(:config);
use IO::File;
use Debbugs::MIME qw(decode_rfc1522);
use Mail::Address;
use Cwd qw(cwd);
+use Storable qw(dclone);
+use Time::HiRes qw(usleep);
+
+use Params::Validate qw(validate_with :types);
-use Fcntl qw(:flock);
+use Fcntl qw(:DEFAULT :flock);
+use Encode qw(is_utf8 decode_utf8);
our $DEBUG_FH = \*STDERR if not defined $DEBUG_FH;
Returns the path to the logfile corresponding to the bug.
+Returns undef if the bug does not exist.
+
=cut
sub buglog {
my $location = getbuglocation($bugnum, 'log');
return getbugcomponent($bugnum, 'log', $location) if ($location);
$location = getbuglocation($bugnum, 'log.gz');
- return getbugcomponent($bugnum, 'log.gz', $location);
+ return getbugcomponent($bugnum, 'log.gz', $location) if ($location);
+ return undef;
}
+=head2 bug_status
+
+ bug_status($bugnum)
+
+
+Returns the path to the summary file corresponding to the bug.
+
+Returns undef if the bug does not exist.
+
+=cut
+
+sub bug_status{
+ my ($bugnum) = @_;
+ my $location = getbuglocation($bugnum, 'summary');
+ return getbugcomponent($bugnum, 'summary', $location) if ($location);
+ return undef;
+}
=head2 appendfile
close $fh or die "Unable to close $file: $!";
}
+=head2 overwritefile
+
+ ovewritefile($file,'data','to','append');
+
+Opens file.new, writes data to it, then moves file.new to file.
+
+=cut
+
+sub overwritefile {
+ my ($file,@data) = @_;
+ my $fh = IO::File->new("${file}.new",'w') or
+ die "Unable top open ${file}.new for writing: $!";
+ print {$fh} @data or die "Unable to write to ${file}.new: $!";
+ close $fh or die "Unable to close ${file}.new: $!";
+ rename("${file}.new",$file) or
+ die "Unable to rename ${file}.new to $file: $!";
+}
+
+=head2 open_compressed_file
+
+ my $fh = open_compressed_file('foo.gz') or
+ die "Unable to open compressed file: $!";
+
+
+Opens a file; if the file ends in .gz, .xz, or .bz2, the appropriate
+decompression program is forked and output from it is read.
+
+This routine by default opens the file with UTF-8 encoding; if you want some
+other encoding, specify it with the second option.
+
+=cut
+sub open_compressed_file {
+ my ($file,$encoding) = @_;
+ $encoding //= ':encoding(UTF-8)';
+ my $fh;
+ my $mode = "<$encoding";
+ my @opts;
+ if ($file =~ /\.gz$/) {
+ $mode = "-|$encoding";
+ push @opts,'gzip','-dc';
+ }
+ if ($file =~ /\.xz$/) {
+ $mode = "-|$encoding";
+ push @opts,'xz','-dc';
+ }
+ if ($file =~ /\.bz2$/) {
+ $mode = "-|$encoding";
+ push @opts,'bzip2','-dc';
+ }
+ open($fh,$mode,@opts,$file);
+ return $fh;
+}
+
+
+
=head2 getparsedaddrs
my $address = getparsedaddrs($address);
=cut
-our $_maintainer;
-our $_maintainer_rev;
+our $_maintainer = undef;
+our $_maintainer_rev = undef;
sub getmaintainers {
- return $_maintainer if $_maintainer;
- my %maintainer;
- my %maintainer_rev;
- for my $file (@config{qw(maintainer_file maintainer_file_override pseduo_maint_file)}) {
- next unless defined $file;
- my $maintfile = IO::File->new($file,'r') or
- die "Unable to open maintainer file $file: $!");
- while(<$maintfile>) {
- next unless m/^(\S+)\s+(\S.*\S)\s*$/;
- ($a,$b)=($1,$2);
- $a =~ y/A-Z/a-z/;
- $maintainer{$a}= $b;
- for my $maint (map {lc($_->address)} getparsedaddrs($b)) {
- push @{$maintainer_rev{$maint}},$a;
- }
- }
- close($maintfile);
- }
- $_maintainer = \%maintainer;
- $_maintainer_rev = \%maintainer_rev;
+ return $_maintainer if defined $_maintainer;
+ package_maintainer(rehash => 1);
return $_maintainer;
}
=cut
sub getmaintainers_reverse{
- return $_maintainer_rev if $_maintainer_rev;
- getmaintainers();
+ return $_maintainer_rev if defined $_maintainer_rev;
+ package_maintainer(rehash => 1);
return $_maintainer_rev;
}
+=head2 getsourcemaintainers
+
+ my $maintainer = getsourcemaintainers()->{debbugs}
+
+Returns a hashref of src_package => maintainer pairs.
+
+=cut
+
+our $_source_maintainer = undef;
+our $_source_maintainer_rev = undef;
+sub getsourcemaintainers {
+ return $_source_maintainer if defined $_source_maintainer;
+ package_maintainer(rehash => 1);
+ return $_source_maintainer;
+}
+
+=head2 getsourcemaintainers_reverse
+
+ my @src_packages = @{getsourcemaintainers_reverse->{'don@debian.org'}||[]};
+
+Returns a hashref of maintainer => [qw(list of source packages)] pairs.
+
+=cut
+
+sub getsourcemaintainers_reverse{
+ return $_source_maintainer_rev if defined $_source_maintainer_rev;
+ package_maintainer(rehash => 1);
+ return $_source_maintainer_rev;
+}
+
+=head2 package_maintainer
+
+ my @s = package_maintainer(source => [qw(foo bar baz)],
+ binary => [qw(bleh blah)],
+ );
+
+=over
+
+=item source -- scalar or arrayref of source package names to return
+maintainers for, defaults to the empty arrayref.
+
+=item binary -- scalar or arrayref of binary package names to return
+maintainers for; automatically returns source package maintainer if
+the package name starts with 'src:', defaults to the empty arrayref.
+
+=item reverse -- whether to return the source/binary packages a
+maintainer maintains instead
+
+=item rehash -- whether to reread the maintainer and source maintainer
+files; defaults to 0
+
+=back
+
+=cut
+
+sub package_maintainer {
+ my %param = validate_with(params => \@_,
+ spec => {source => {type => SCALAR|ARRAYREF,
+ default => [],
+ },
+ binary => {type => SCALAR|ARRAYREF,
+ default => [],
+ },
+ maintainer => {type => SCALAR|ARRAYREF,
+ default => [],
+ },
+ rehash => {type => BOOLEAN,
+ default => 0,
+ },
+ reverse => {type => BOOLEAN,
+ default => 0,
+ },
+ },
+ );
+ my @binary = make_list($param{binary});
+ my @source = make_list($param{source});
+ my @maintainers = make_list($param{maintainer});
+ if ((@binary or @source) and @maintainers) {
+ croak "It is nonsensical to pass both maintainers and source or binary";
+ }
+ if ($param{rehash}) {
+ $_source_maintainer = undef;
+ $_source_maintainer_rev = undef;
+ $_maintainer = undef;
+ $_maintainer_rev = undef;
+ }
+ if (not defined $_source_maintainer or
+ not defined $_source_maintainer_rev) {
+ $_source_maintainer = {};
+ $_source_maintainer_rev = {};
+ for my $fn (@config{('source_maintainer_file',
+ 'source_maintainer_file_override',
+ 'pseudo_maint_file')}) {
+ next unless defined $fn and length $fn;
+ if (not -e $fn) {
+ warn "Missing source maintainer file '$fn'";
+ next;
+ }
+ __add_to_hash($fn,$_source_maintainer,
+ $_source_maintainer_rev);
+ }
+ }
+ if (not defined $_maintainer or
+ not defined $_maintainer_rev) {
+ $_maintainer = {};
+ $_maintainer_rev = {};
+ for my $fn (@config{('maintainer_file',
+ 'maintainer_file_override',
+ 'pseudo_maint_file')}) {
+ next unless defined $fn and length $fn;
+ if (not -e $fn) {
+ warn "Missing maintainer file '$fn'";
+ next;
+ }
+ __add_to_hash($fn,$_maintainer,
+ $_maintainer_rev);
+ }
+ }
+ my @return;
+ for my $binary (@binary) {
+ if (not $param{reverse} and $binary =~ /^src:/) {
+ push @source,$binary;
+ next;
+ }
+ push @return,grep {defined $_} make_list($_maintainer->{$binary});
+ }
+ for my $source (@source) {
+ $source =~ s/^src://;
+ push @return,grep {defined $_} make_list($_source_maintainer->{$source});
+ }
+ for my $maintainer (grep {defined $_} @maintainers) {
+ push @return,grep {defined $_}
+ make_list($_maintainer_rev->{$maintainer});
+ push @return,map {$_ !~ /^src:/?'src:'.$_:$_}
+ grep {defined $_}
+ make_list($_source_maintainer_rev->{$maintainer});
+ }
+ return @return;
+}
+
+#=head2 __add_to_hash
+#
+# __add_to_hash($file,$forward_hash,$reverse_hash,'address');
+#
+# Reads a maintainer/source maintainer/pseudo desc file and adds the
+# maintainers from it to the forward and reverse hashref; assumes that
+# the forward is unique; makes no assumptions of the reverse.
+#
+#=cut
+
+sub __add_to_hash {
+ my ($fn,$forward,$reverse,$type) = @_;
+ if (ref($forward) ne 'HASH') {
+ croak "__add_to_hash must be passed a hashref for the forward";
+ }
+ if (defined $reverse and not ref($reverse) eq 'HASH') {
+ croak "if reverse is passed to __add_to_hash, it must be a hashref";
+ }
+ $type //= 'address';
+ my $fh = IO::File->new($fn,'r') or
+ croak "Unable to open $fn for reading: $!";
+ binmode($fh,':encoding(UTF-8)');
+ while (<$fh>) {
+ chomp;
+ next unless m/^(\S+)\s+(\S.*\S)\s*$/;
+ my ($key,$value)=($1,$2);
+ $key = lc $key;
+ $forward->{$key}= $value;
+ if (defined $reverse) {
+ if ($type eq 'address') {
+ for my $m (map {lc($_->address)} (getparsedaddrs($value))) {
+ push @{$reverse->{$m}},$key;
+ }
+ }
+ else {
+ push @{$reverse->{$value}}, $key;
+ }
+ }
+ }
+}
+
+
=head2 getpseudodesc
my $pseudopkgdesc = getpseudodesc(...);
=cut
-our $_pseudodesc;
+our $_pseudodesc = undef;
sub getpseudodesc {
- return $_pseudodesc if $_pseudodesc;
- my %pseudodesc;
-
- if (not defined $config{pseudo_desc_file}) {
- $_pseudodesc = {};
- return $_pseudodesc;
- }
- my $pseudo = IO::File->new($config{pseudo_desc_file},'r')
- or die "Unable to open $config{pseudo_desc_file}: $!";
- while(<$pseudo>) {
- next unless m/^(\S+)\s+(\S.*\S)\s*$/;
- $pseudodesc{lc $1} = $2;
- }
- close($pseudo);
- $_pseudodesc = \%pseudodesc;
+ return $_pseudodesc if defined $_pseudodesc;
+ $_pseudodesc = {};
+ __add_to_hash($config{pseudo_desc_file},$_pseudodesc) if
+ defined $config{pseudo_desc_file} and
+ length $config{pseudo_desc_file};
return $_pseudodesc;
}
+=head2 sort_versions
+
+ sort_versions('1.0-2','1.1-2');
+
+Sorts versions using AptPkg::Versions::compare if it is available, or
+Debbugs::Versions::Dpkg::vercmp if it isn't.
+
+=cut
+
+our $vercmp;
+BEGIN{
+ use Debbugs::Versions::Dpkg;
+ $vercmp=\&Debbugs::Versions::Dpkg::vercmp;
+
+# eventually we'll use AptPkg:::Version or similar, but the current
+# implementation makes this *super* difficult.
+
+# eval {
+# use AptPkg::Version;
+# $vercmp=\&AptPkg::Version::compare;
+# };
+}
+
+sub sort_versions{
+ return sort {$vercmp->($a,$b)} @_;
+}
+
=head1 DATE
=head2 filelock
- filelock
+ filelock($lockfile);
+ filelock($lockfile,$locks);
FLOCKs the passed file. Use unfilelock to unlock it.
+Can be passed an optional $locks hashref, which is used to track which
+files are locked (and how many times they have been locked) to allow
+for cooperative locking.
+
=cut
our @filelocks;
+use Carp qw(cluck);
+
sub filelock {
# NB - NOT COMPATIBLE WITH `with-lock'
- my ($lockfile) = @_;
+ my ($lockfile,$locks) = @_;
if ($lockfile !~ m{^/}) {
$lockfile = cwd().'/'.$lockfile;
}
- my ($count,$errors);
- $count= 10; $errors= '';
- for (;;) {
- my $fh = eval {
+ # This is only here to allow for relocking bugs inside of
+ # Debbugs::Control. Nothing else should be using it.
+ if (defined $locks and exists $locks->{locks}{$lockfile} and
+ $locks->{locks}{$lockfile} >= 1) {
+ if (exists $locks->{relockable} and
+ exists $locks->{relockable}{$lockfile}) {
+ $locks->{locks}{$lockfile}++;
+ # indicate that the bug for this lockfile needs to be reread
+ $locks->{relockable}{$lockfile} = 1;
+ push @{$locks->{lockorder}},$lockfile;
+ return;
+ }
+ else {
+ use Data::Dumper;
+ confess "Locking already locked file: $lockfile\n".Data::Dumper->Dump([$lockfile,$locks],[qw(lockfile locks)]);
+ }
+ }
+ my ($fh,$t_lockfile,$errors) =
+ simple_filelock($lockfile,10,1);
+ if ($fh) {
+ push @filelocks, {fh => $fh, file => $lockfile};
+ if (defined $locks) {
+ $locks->{locks}{$lockfile}++;
+ push @{$locks->{lockorder}},$lockfile;
+ }
+ } else {
+ use Data::Dumper;
+ croak "failed to get lock on $lockfile -- $errors".
+ (defined $locks?Data::Dumper->Dump([$locks],[qw(locks)]):'');
+ }
+}
+
+=head2 simple_filelock
+
+ my ($fh,$t_lockfile,$errors) =
+ simple_filelock($lockfile,$count,$wait);
+
+Does a flock of lockfile. If C<$count> is zero, does a blocking lock.
+Otherwise, does a non-blocking lock C<$count> times, waiting C<$wait>
+seconds in between.
+
+In list context, returns the lockfile filehandle, lockfile name, and
+any errors which occured.
+
+When the lockfile filehandle is undef, locking failed.
+
+These lockfiles must be unlocked manually at process end.
+
+
+=cut
+
+sub simple_filelock {
+ my ($lockfile,$count,$wait) = @_;
+ if (not defined $count) {
+ $count = 10;
+ }
+ if ($count < 0) {
+ $count = 0;
+ }
+ if (not defined $wait) {
+ $wait = 1;
+ }
+ my $errors= '';
+ my $fh;
+ while (1) {
+ $fh = eval {
my $fh2 = IO::File->new($lockfile,'w')
or die "Unable to open $lockfile for writing: $!";
- flock($fh2,LOCK_EX|LOCK_NB)
+ # Do a blocking lock if count is zero
+ flock($fh2,LOCK_EX|($count == 0?0:LOCK_NB))
or die "Unable to lock $lockfile $!";
return $fh2;
};
if ($@) {
$errors .= $@;
}
- if ($fh) {
- push @filelocks, {fh => $fh, file => $lockfile};
- last;
- }
- if (--$count <=0) {
- $errors =~ s/\n+$//;
- die "failed to get lock on $lockfile -- $errors";
+ if ($fh) {
+ last;
}
- sleep 10;
+ # use usleep for fractional wait seconds
+ usleep($wait * 1_000_000);
+ } continue {
+ last unless (--$count > 0);
+ }
+ if ($fh) {
+ return wantarray?($fh,$lockfile,$errors):$fh
}
+ return wantarray?(undef,$lockfile,$errors):undef;
}
# clean up all outstanding locks at end time
}
}
+=head2 simple_unlockfile
+
+ simple_unlockfile($fh,$lockfile);
+
+
+=cut
+
+sub simple_unlockfile {
+ my ($fh,$lockfile) = @_;
+ flock($fh,LOCK_UN)
+ or warn "Unable to unlock lockfile $lockfile: $!";
+ close($fh)
+ or warn "Unable to close lockfile $lockfile: $!";
+ unlink($lockfile)
+ or warn "Unable to unlink lockfile $lockfile: $!";
+}
+
=head2 unfilelock
unfilelock()
+ unfilelock($locks);
Unlocks the file most recently locked.
=cut
sub unfilelock {
+ my ($locks) = @_;
if (@filelocks == 0) {
- warn "unfilelock called with no active filelocks!\n";
+ carp "unfilelock called with no active filelocks!\n";
return;
}
+ if (defined $locks and ref($locks) ne 'HASH') {
+ croak "hash not passsed to unfilelock";
+ }
+ if (defined $locks and exists $locks->{lockorder} and
+ @{$locks->{lockorder}} and
+ exists $locks->{locks}{$locks->{lockorder}[-1]}) {
+ my $lockfile = pop @{$locks->{lockorder}};
+ $locks->{locks}{$lockfile}--;
+ if ($locks->{locks}{$lockfile} > 0) {
+ return
+ }
+ delete $locks->{locks}{$lockfile};
+ }
my %fl = %{pop(@filelocks)};
- flock($fl{fh},LOCK_UN)
- or warn "Unable to unlock lockfile $fl{file}: $!";
- close($fl{fh})
- or warn "Unable to close lockfile $fl{file}: $!";
- unlink($fl{file})
- or warn "Unable to unlink lockfile $fl{file}: $!";
+ simple_unlockfile($fl{fh},$fl{file});
}
sub lockpid {
my ($pidfile) = @_;
if (-e $pidfile) {
- my $pidfh = IO::File->new($pidfile, 'r') or
- die "Unable to open pidfile $pidfile: $!";
- local $/;
- my $pid = <$pidfh>;
- ($pid) = $pid =~ /(\d+)/;
- if (defined $pid and kill(0,$pid)) {
- return 0;
- }
- close $pidfh;
+ my $pid = checkpid($pidfile);
+ die "Unable to read pidfile $pidfile: $!" if not defined $pid;
+ return 0 if $pid != 0;
unlink $pidfile or
die "Unable to unlink stale pidfile $pidfile $!";
}
- my $pidfh = IO::File->new($pidfile,'w') or
+ my $pidfh = IO::File->new($pidfile,O_CREAT|O_EXCL|O_WRONLY) or
die "Unable to open $pidfile for writing: $!";
print {$pidfh} $$ or die "Unable to write to $pidfile $!";
close $pidfh or die "Unable to close $pidfile $!";
return 1;
}
+=head2 checkpid
+
+ checkpid('/path/to/pidfile');
+
+Checks a pid file and determines if the process listed in the pidfile
+is still running. Returns the pid if it is, 0 if it isn't running, and
+undef if the pidfile doesn't exist or cannot be read.
+
+=cut
+
+sub checkpid{
+ my ($pidfile) = @_;
+ if (-e $pidfile) {
+ my $pidfh = IO::File->new($pidfile, 'r') or
+ return undef;
+ local $/;
+ my $pid = <$pidfh>;
+ close $pidfh;
+ ($pid) = $pid =~ /(\d+)/;
+ if (defined $pid and kill(0,$pid)) {
+ return $pid;
+ }
+ return 0;
+ }
+ else {
+ return undef;
+ }
+}
+
=head1 QUIT
}
+=head2 english_join
+
+ print english_join(list => \@list);
+ print english_join(\@list);
+
+Joins list properly to make an english phrase.
+
+=over
+
+=item normal -- how to separate most values; defaults to ', '
+
+=item last -- how to separate the last two values; defaults to ', and '
+
+=item only_two -- how to separate only two values; defaults to ' and '
+
+=item list -- ARRAYREF values to join; if the first argument is an
+ARRAYREF, it's assumed to be the list of values to join
+
+=back
+
+In cases where C<list> is empty, returns ''; when there is only one
+element, returns that element.
+
+=cut
+
+sub english_join {
+ if (ref $_[0] eq 'ARRAY') {
+ return english_join(list=>$_[0]);
+ }
+ my %param = validate_with(params => \@_,
+ spec => {normal => {type => SCALAR,
+ default => ', ',
+ },
+ last => {type => SCALAR,
+ default => ', and ',
+ },
+ only_two => {type => SCALAR,
+ default => ' and ',
+ },
+ list => {type => ARRAYREF,
+ },
+ },
+ );
+ my @list = @{$param{list}};
+ if (@list <= 1) {
+ return @list?$list[0]:'';
+ }
+ elsif (@list == 2) {
+ return join($param{only_two},@list);
+ }
+ my $ret = $param{last} . pop(@list);
+ return join($param{normal},@list) . $ret;
+}
+
+
=head2 globify_scalar
my $handle = globify_scalar(\$foo);
globref), and return /dev/null. May return undef if IO::Scalar or
IO::File fails. (Check $!)
+The scalar will fill with octets, not perl's internal encoding, so you
+must use decode_utf8() after on the scalar, and encode_utf8() on it
+before. This appears to be a bug in the underlying modules.
+
=cut
sub globify_scalar {
if (defined ref($scalar)) {
if (ref($scalar) eq 'SCALAR' and
not UNIVERSAL::isa($scalar,'GLOB')) {
- return IO::Scalar->new($scalar);
+ if (is_utf8(${$scalar})) {
+ ${$scalar} = decode_utf8(${$scalar});
+ carp(q(\$scalar must not be in perl's internal encoding));
+ }
+ open $handle, '>:scalar:utf8', $scalar;
+ return $handle;
}
else {
return $scalar;
carp "Given a non-scalar reference, non-glob to globify_scalar; returning /dev/null handle";
}
}
- return IO::File->new('/dev/null','w');
+ return IO::File->new('/dev/null','>:encoding(UTF-8)');
+}
+
+=head2 cleanup_eval_fail()
+
+ print "Something failed with: ".cleanup_eval_fail($@);
+
+Does various bits of cleanup on the failure message from an eval (or
+any other die message)
+
+Takes at most two options; the first is the actual failure message
+(usually $@ and defaults to $@), the second is the debug level
+(defaults to $DEBUG).
+
+If debug is non-zero, the code at which the failure occured is output.
+
+=cut
+
+sub cleanup_eval_fail {
+ my ($error,$debug) = @_;
+ if (not defined $error or not @_) {
+ $error = $@ // 'unknown reason';
+ }
+ if (@_ <= 1) {
+ $debug = $DEBUG // 0;
+ }
+ $debug = 0 if not defined $debug;
+
+ if ($debug > 0) {
+ return $error;
+ }
+ # ditch the "at foo/bar/baz.pm line 5"
+ $error =~ s/\sat\s\S+\sline\s\d+//;
+ # ditch croak messages
+ $error =~ s/^\t+.+\n?//mg;
+ # ditch trailing multiple periods in case there was a cascade of
+ # die messages.
+ $error =~ s/\.+$/\./;
+ return $error;
+}
+
+=head2 hash_slice
+
+ hash_slice(%hash,qw(key1 key2 key3))
+
+For each key, returns matching values and keys of the hash if they exist
+
+=cut
+
+
+# NB: We use prototypes here SPECIFICALLY so that we can be passed a
+# hash without uselessly making a reference to first. DO NOT USE
+# PROTOTYPES USELESSLY ELSEWHERE.
+sub hash_slice(\%@) {
+ my ($hashref,@keys) = @_;
+ return map {exists $hashref->{$_}?($_,$hashref->{$_}):()} @keys;
}