diff -ruN Tie-File-0.97/File.pm Tie-File-0.98/File.pm --- Tie-File-0.97/File.pm 1970-01-01 09:00:00.000000000 +0900 +++ Tie-File-0.98/File.pm 2006-12-22 23:05:36.000000000 +0900 @@ -0,0 +1,2639 @@ + +package Tie::File; +require 5.005; +use Carp ':DEFAULT', 'confess'; +use POSIX 'SEEK_SET'; +use Fcntl 'O_CREAT', 'O_RDWR', 'LOCK_EX', 'LOCK_SH', 'O_WRONLY', 'O_RDONLY'; +sub O_ACCMODE () { O_RDONLY | O_RDWR | O_WRONLY } + + +$VERSION = "0.96"; +my $DEFAULT_MEMORY_SIZE = 1<<21; # 2 megabytes +my $DEFAULT_AUTODEFER_THRESHHOLD = 3; # 3 records +my $DEFAULT_AUTODEFER_FILELEN_THRESHHOLD = 65536; # 16 disk blocksful + +my %good_opt = map {$_ => 1, "-$_" => 1} + qw(memory dw_size mode recsep discipline + autodefer autochomp autodefer_threshhold); + +sub TIEARRAY { + if (@_ % 2 != 0) { + croak "usage: tie \@array, $_[0], filename, [option => value]..."; + } + my ($pack, $file, %opts) = @_; + + # transform '-foo' keys into 'foo' keys + for my $key (keys %opts) { + unless ($good_opt{$key}) { + croak("$pack: Unrecognized option '$key'\n"); + } + my $okey = $key; + if ($key =~ s/^-+//) { + $opts{$key} = delete $opts{$okey}; + } + } + + unless (defined $opts{memory}) { + # default is the larger of the default cache size and the + # deferred-write buffer size (if specified) + $opts{memory} = $DEFAULT_MEMORY_SIZE; + $opts{memory} = $opts{dw_size} + if defined $opts{dw_size} && $opts{dw_size} > $DEFAULT_MEMORY_SIZE; + # Dora Winifred Read + } + $opts{dw_size} = $opts{memory} unless defined $opts{dw_size}; + if ($opts{dw_size} > $opts{memory}) { + croak("$pack: dw_size may not be larger than total memory allocation\n"); + } + # are we in deferred-write mode? + $opts{defer} = 0 unless defined $opts{defer}; + $opts{deferred} = {}; # no records are presently deferred + $opts{deferred_s} = 0; # count of total bytes in ->{deferred} + $opts{deferred_max} = -1; # empty + + # What's a good way to arrange that this class can be overridden? + $opts{cache} = Tie::File::Cache->new($opts{memory}); + + # autodeferment is enabled by default + $opts{autodefer} = 1 unless defined $opts{autodefer}; + $opts{autodeferring} = 0; # but is not initially active + $opts{ad_history} = []; + $opts{autodefer_threshhold} = $DEFAULT_AUTODEFER_THRESHHOLD + unless defined $opts{autodefer_threshhold}; + $opts{autodefer_filelen_threshhold} = $DEFAULT_AUTODEFER_FILELEN_THRESHHOLD + unless defined $opts{autodefer_filelen_threshhold}; + + $opts{offsets} = [0]; + $opts{filename} = $file; + unless (defined $opts{recsep}) { + $opts{recsep} = _default_recsep(); + } + $opts{recseplen} = length($opts{recsep}); + if ($opts{recseplen} == 0) { + croak "Empty record separator not supported by $pack"; + } + + $opts{autochomp} = 1 unless defined $opts{autochomp}; + + $opts{mode} = O_CREAT|O_RDWR unless defined $opts{mode}; + $opts{rdonly} = (($opts{mode} & O_ACCMODE) == O_RDONLY); + $opts{sawlastrec} = undef; + + my $fh; + + if (UNIVERSAL::isa($file, 'GLOB')) { + # We use 1 here on the theory that some systems + # may not indicate failure if we use 0. + # MSWin32 does not indicate failure with 0, but I don't know if + # it will indicate failure with 1 or not. + unless (seek $file, 1, SEEK_SET) { + croak "$pack: your filehandle does not appear to be seekable"; + } + seek $file, 0, SEEK_SET # put it back + $fh = $file; # setting binmode is the user's problem + } elsif (ref $file) { + croak "usage: tie \@array, $pack, filename, [option => value]..."; + } else { + # $fh = \do { local *FH }; # XXX this is buggy + if ($] < 5.006) { + # perl 5.005 and earlier don't autovivify filehandles + require Symbol; + $fh = Symbol::gensym(); + } + if (!defined($file) && $] >= 5.008 && PerlIO::Layer->find('perlio')) { + # Try in-memory file if perl supports perlio -- dankogai + my $memfile; + open $fh, '+>', \$memfile or return; + $opts{memfile} = \$memfile; + }else{ + sysopen $fh, $file, $opts{mode}, 0666 or return; + } + binmode $fh; + ++$opts{ourfh}; + } + { my $ofh = select $fh; $| = 1; select $ofh } # autoflush on write + if (defined $opts{discipline} && $] >= 5.006) { + # This avoids a compile-time warning under 5.005 + eval 'binmode($fh, $opts{discipline})'; + croak $@ if $@ =~ /unknown discipline/i; + die if $@; + } + $opts{fh} = $fh; + + bless \%opts => $pack; +} + +sub FETCH { + my ($self, $n) = @_; + my $rec; + + # check the defer buffer + $rec = $self->{deferred}{$n} if exists $self->{deferred}{$n}; + $rec = $self->_fetch($n) unless defined $rec; + + # inlined _chomp1 + substr($rec, - $self->{recseplen}) = "" + if defined $rec && $self->{autochomp}; + $rec; +} + +# Chomp many records in-place; return nothing useful +sub _chomp { + my $self = shift; + return unless $self->{autochomp}; + if ($self->{autochomp}) { + for (@_) { + next unless defined; + substr($_, - $self->{recseplen}) = ""; + } + } +} + +# Chomp one record in-place; return modified record +sub _chomp1 { + my ($self, $rec) = @_; + return $rec unless $self->{autochomp}; + return unless defined $rec; + substr($rec, - $self->{recseplen}) = ""; + $rec; +} + +sub _fetch { + my ($self, $n) = @_; + + # check the record cache + { my $cached = $self->{cache}->lookup($n); + return $cached if defined $cached; + } + + if ($#{$self->{offsets}} < $n) { + return if $self->{eof}; # request for record beyond end of file + my $o = $self->_fill_offsets_to($n); + # If it's still undefined, there is no such record, so return 'undef' + return unless defined $o; + } + + my $fh = $self->{FH}; + $self->_seek($n); # we can do this now that offsets is populated + my $rec = $self->_read_record; + +# If we happen to have just read the first record, check to see if +# the length of the record matches what 'tell' says. If not, Tie::File +# won't work, and should drop dead. +# +# if ($n == 0 && defined($rec) && tell($self->{fh}) != length($rec)) { +# if (defined $self->{discipline}) { +# croak "I/O discipline $self->{discipline} not supported"; +# } else { +# croak "File encoding not supported"; +# } +# } + + $self->{cache}->insert($n, $rec) if defined $rec && not $self->{flushing}; + $rec; +} + +sub STORE { + my ($self, $n, $rec) = @_; + die "STORE called from _check_integrity!" if $DIAGNOSTIC; + + $self->_fixrecs($rec); + + if ($self->{autodefer}) { + $self->_annotate_ad_history($n); + } + + return $self->_store_deferred($n, $rec) if $self->_is_deferring; + + + # We need this to decide whether the new record will fit + # It incidentally populates the offsets table + # Note we have to do this before we alter the cache + # 20020324 Wait, but this DOES alter the cache. TODO BUG? + my $oldrec = $self->_fetch($n); + + if (not defined $oldrec) { + # We're storing a record beyond the end of the file + $self->_extend_file_to($n+1); + $oldrec = $self->{recsep}; + } +# return if $oldrec eq $rec; # don't bother + my $len_diff = length($rec) - length($oldrec); + + # length($oldrec) here is not consistent with text mode TODO XXX BUG + $self->_mtwrite($rec, $self->{offsets}[$n], length($oldrec)); + $self->_oadjust([$n, 1, $rec]); + $self->{cache}->update($n, $rec); +} + +sub _store_deferred { + my ($self, $n, $rec) = @_; + $self->{cache}->remove($n); + my $old_deferred = $self->{deferred}{$n}; + + if (defined $self->{deferred_max} && $n > $self->{deferred_max}) { + $self->{deferred_max} = $n; + } + $self->{deferred}{$n} = $rec; + + my $len_diff = length($rec); + $len_diff -= length($old_deferred) if defined $old_deferred; + $self->{deferred_s} += $len_diff; + $self->{cache}->adj_limit(-$len_diff); + if ($self->{deferred_s} > $self->{dw_size}) { + $self->_flush; + } elsif ($self->_cache_too_full) { + $self->_cache_flush; + } +} + +# Remove a single record from the deferred-write buffer without writing it +# The record need not be present +sub _delete_deferred { + my ($self, $n) = @_; + my $rec = delete $self->{deferred}{$n}; + return unless defined $rec; + + if (defined $self->{deferred_max} + && $n == $self->{deferred_max}) { + undef $self->{deferred_max}; + } + + $self->{deferred_s} -= length $rec; + $self->{cache}->adj_limit(length $rec); +} + +sub FETCHSIZE { + my $self = shift; + my $n = $self->{eof} ? $#{$self->{offsets}} : $self->_fill_offsets; + + my $top_deferred = $self->_defer_max; + $n = $top_deferred+1 if defined $top_deferred && $n < $top_deferred+1; + $n; +} + +sub STORESIZE { + my ($self, $len) = @_; + + if ($self->{autodefer}) { + $self->_annotate_ad_history('STORESIZE'); + } + + my $olen = $self->FETCHSIZE; + return if $len == $olen; # Woo-hoo! + + # file gets longer + if ($len > $olen) { + if ($self->_is_deferring) { + for ($olen .. $len-1) { + $self->_store_deferred($_, $self->{recsep}); + } + } else { + $self->_extend_file_to($len); + } + return; + } + + # file gets shorter + if ($self->_is_deferring) { + # TODO maybe replace this with map-plus-assignment? + for (grep $_ >= $len, keys %{$self->{deferred}}) { + $self->_delete_deferred($_); + } + $self->{deferred_max} = $len-1; + } + + $self->_seek($len); + $self->_chop_file; + $#{$self->{offsets}} = $len; +# $self->{offsets}[0] = 0; # in case we just chopped this + + $self->{cache}->remove(grep $_ >= $len, $self->{cache}->ckeys); +} + +### OPTIMIZE ME +### It should not be necessary to do FETCHSIZE +### Just seek to the end of the file. +sub PUSH { + my $self = shift; + $self->SPLICE($self->FETCHSIZE, scalar(@_), @_); + + # No need to return: + # $self->FETCHSIZE; # because av.c takes care of this for me +} + +sub POP { + my $self = shift; + my $size = $self->FETCHSIZE; + return if $size == 0; +# print STDERR "# POPPITY POP POP POP\n"; + scalar $self->SPLICE($size-1, 1); +} + +sub SHIFT { + my $self = shift; + scalar $self->SPLICE(0, 1); +} + +sub UNSHIFT { + my $self = shift; + $self->SPLICE(0, 0, @_); + # $self->FETCHSIZE; # av.c takes care of this for me +} + +sub CLEAR { + my $self = shift; + + if ($self->{autodefer}) { + $self->_annotate_ad_history('CLEAR'); + } + + $self->_seekb(0); + $self->_chop_file; + $self->{cache}->set_limit($self->{memory}); + $self->{cache}->empty; + @{$self->{offsets}} = (0); + %{$self->{deferred}}= (); + $self->{deferred_s} = 0; + $self->{deferred_max} = -1; +} + +sub EXTEND { + my ($self, $n) = @_; + + # No need to pre-extend anything in this case + return if $self->_is_deferring; + + $self->_fill_offsets_to($n); + $self->_extend_file_to($n); +} + +sub DELETE { + my ($self, $n) = @_; + + if ($self->{autodefer}) { + $self->_annotate_ad_history('DELETE'); + } + + my $lastrec = $self->FETCHSIZE-1; + my $rec = $self->FETCH($n); + $self->_delete_deferred($n) if $self->_is_deferring; + if ($n == $lastrec) { + $self->_seek($n); + $self->_chop_file; + $#{$self->{offsets}}--; + $self->{cache}->remove($n); + # perhaps in this case I should also remove trailing null records? + # 20020316 + # Note that delete @a[-3..-1] deletes the records in the wrong order, + # so we only chop the very last one out of the file. We could repair this + # by tracking deleted records inside the object. + } elsif ($n < $lastrec) { + $self->STORE($n, ""); + } + $rec; +} + +sub EXISTS { + my ($self, $n) = @_; + return 1 if exists $self->{deferred}{$n}; + $n < $self->FETCHSIZE; +} + +sub SPLICE { + my $self = shift; + + if ($self->{autodefer}) { + $self->_annotate_ad_history('SPLICE'); + } + + $self->_flush if $self->_is_deferring; # move this up? + if (wantarray) { + $self->_chomp(my @a = $self->_splice(@_)); + @a; + } else { + $self->_chomp1(scalar $self->_splice(@_)); + } +} + +sub DESTROY { + my $self = shift; + $self->flush if $self->_is_deferring; + $self->{cache}->delink if defined $self->{cache}; # break circular link + if ($self->{fh} and $self->{ourfh}) { + delete $self->{ourfh}; + close delete $self->{fh}; + } +} + +sub _splice { + my ($self, $pos, $nrecs, @data) = @_; + my @result; + + $pos = 0 unless defined $pos; + + # Deal with negative and other out-of-range positions + # Also set default for $nrecs + { + my $oldsize = $self->FETCHSIZE; + $nrecs = $oldsize unless defined $nrecs; + my $oldpos = $pos; + + if ($pos < 0) { + $pos += $oldsize; + if ($pos < 0) { + croak "Modification of non-creatable array value attempted, subscript $oldpos"; + } + } + + if ($pos > $oldsize) { + return unless @data; + $pos = $oldsize; # This is what perl does for normal arrays + } + + # The manual is very unclear here + if ($nrecs < 0) { + $nrecs = $oldsize - $pos + $nrecs; + $nrecs = 0 if $nrecs < 0; + } + + # nrecs is too big---it really means "until the end" + # 20030507 + if ($nrecs + $pos > $oldsize) { + $nrecs = $oldsize - $pos; + } + } + + $self->_fixrecs(@data); + my $data = join '', @data; + my $datalen = length $data; + my $oldlen = 0; + + # compute length of data being removed + for ($pos .. $pos+$nrecs-1) { + last unless defined $self->_fill_offsets_to($_); + my $rec = $self->_fetch($_); + last unless defined $rec; + push @result, $rec; + + # Why don't we just use length($rec) here? + # Because that record might have come from the cache. _splice + # might have been called to flush out the deferred-write records, + # and in this case length($rec) is the length of the record to be + # *written*, not the length of the actual record in the file. But + # the offsets are still true. 20020322 + $oldlen += $self->{offsets}[$_+1] - $self->{offsets}[$_] + if defined $self->{offsets}[$_+1]; + } + $self->_fill_offsets_to($pos+$nrecs); + + # Modify the file + $self->_mtwrite($data, $self->{offsets}[$pos], $oldlen); + # Adjust the offsets table + $self->_oadjust([$pos, $nrecs, @data]); + + { # Take this read cache stuff out into a separate function + # You made a half-attempt to put it into _oadjust. + # Finish something like that up eventually. + # STORE also needs to do something similarish + + # update the read cache, part 1 + # modified records + for ($pos .. $pos+$nrecs-1) { + my $new = $data[$_-$pos]; + if (defined $new) { + $self->{cache}->update($_, $new); + } else { + $self->{cache}->remove($_); + } + } + + # update the read cache, part 2 + # moved records - records past the site of the change + # need to be renumbered + # Maybe merge this with the previous block? + { + my @oldkeys = grep $_ >= $pos + $nrecs, $self->{cache}->ckeys; + my @newkeys = map $_-$nrecs+@data, @oldkeys; + $self->{cache}->rekey(\@oldkeys, \@newkeys); + } + + # Now there might be too much data in the cache, if we spliced out + # some short records and spliced in some long ones. If so, flush + # the cache. + $self->_cache_flush; + } + + # Yes, the return value of 'splice' *is* actually this complicated + wantarray ? @result : @result ? $result[-1] : undef; +} + + +# write data into the file +# $data is the data to be written. +# it should be written at position $pos, and should overwrite +# exactly $len of the following bytes. +# Note that if length($data) > $len, the subsequent bytes will have to +# be moved up, and if length($data) < $len, they will have to +# be moved down +sub _twrite { + my ($self, $data, $pos, $len) = @_; + + unless (defined $pos) { + die "\$pos was undefined in _twrite"; + } + + my $len_diff = length($data) - $len; + + if ($len_diff == 0) { # Woo-hoo! + my $fh = $self->{fh}; + $self->_seekb($pos); + $self->_write_record($data); + return; # well, that was easy. + } + + # the two records are of different lengths + # our strategy here: rewrite the tail of the file, + # reading ahead one buffer at a time + # $bufsize is required to be at least as large as the data we're overwriting + my $bufsize = _bufsize($len_diff); + my ($writepos, $readpos) = ($pos, $pos+$len); + my $next_block; + my $more_data; + + # Seems like there ought to be a way to avoid the repeated code + # and the special case here. The read(1) is also a little weird. + # Think about this. + do { + $self->_seekb($readpos); + my $br = read $self->{fh}, $next_block, $bufsize; + $more_data = read $self->{fh}, my($dummy), 1; + $self->_seekb($writepos); + $self->_write_record($data); + $readpos += $br; + $writepos += length $data; + $data = $next_block; + } while $more_data; + $self->_seekb($writepos); + $self->_write_record($next_block); + + # There might be leftover data at the end of the file + $self->_chop_file if $len_diff < 0; +} + +# _iwrite(D, S, E) +# Insert text D at position S. +# Let C = E-S-|D|. If C < 0; die. +# Data in [S,S+C) is copied to [S+D,S+D+C) = [S+D,E). +# Data in [S+C = E-D, E) is returned. Data in [E, oo) is untouched. +# +# In a later version, don't read the entire intervening area into +# memory at once; do the copying block by block. +sub _iwrite { + my $self = shift; + my ($D, $s, $e) = @_; + my $d = length $D; + my $c = $e-$s-$d; + local *FH = $self->{fh}; + confess "Not enough space to insert $d bytes between $s and $e" + if $c < 0; + confess "[$s,$e) is an invalid insertion range" if $e < $s; + + $self->_seekb($s); + read FH, my $buf, $e-$s; + + $D .= substr($buf, 0, $c, ""); + + $self->_seekb($s); + $self->_write_record($D); + + return $buf; +} + +# Like _twrite, but the data-pos-len triple may be repeated; you may +# write several chunks. All the writing will be done in +# one pass. Chunks SHALL be in ascending order and SHALL NOT overlap. +sub _mtwrite { + my $self = shift; + my $unwritten = ""; + my $delta = 0; + + @_ % 3 == 0 + or die "Arguments to _mtwrite did not come in groups of three"; + + while (@_) { + my ($data, $pos, $len) = splice @_, 0, 3; + my $end = $pos + $len; # The OLD end of the segment to be replaced + $data = $unwritten . $data; + $delta -= length($unwritten); + $unwritten = ""; + $pos += $delta; # This is where the data goes now + my $dlen = length $data; + $self->_seekb($pos); + if ($len >= $dlen) { # the data will fit + $self->_write_record($data); + $delta += ($dlen - $len); # everything following moves down by this much + $data = ""; # All the data in the buffer has been written + } else { # won't fit + my $writable = substr($data, 0, $len - $delta, ""); + $self->_write_record($writable); + $delta += ($dlen - $len); # everything following moves down by this much + } + + # At this point we've written some but maybe not all of the data. + # There might be a gap to close up, or $data might still contain a + # bunch of unwritten data that didn't fit. + my $ndlen = length $data; + if ($delta == 0) { + $self->_write_record($data); + } elsif ($delta < 0) { + # upcopy (close up gap) + if (@_) { + $self->_upcopy($end, $end + $delta, $_[1] - $end); + } else { + $self->_upcopy($end, $end + $delta); + } + } else { + # downcopy (insert data that didn't fit; replace this data in memory + # with _later_ data that doesn't fit) + if (@_) { + $unwritten = $self->_downcopy($data, $end, $_[1] - $end); + } else { + # Make the file longer to accomodate the last segment that doesn' + $unwritten = $self->_downcopy($data, $end); + } + } + } +} + +# Copy block of data of length $len from position $spos to position $dpos +# $dpos must be <= $spos +# +# If $len is undefined, go all the way to the end of the file +# and then truncate it ($spos - $dpos bytes will be removed) +sub _upcopy { + my $blocksize = 8192; + my ($self, $spos, $dpos, $len) = @_; + if ($dpos > $spos) { + die "source ($spos) was upstream of destination ($dpos) in _upcopy"; + } elsif ($dpos == $spos) { + return; + } + + while (! defined ($len) || $len > 0) { + my $readsize = ! defined($len) ? $blocksize + : $len > $blocksize ? $blocksize + : $len; + + my $fh = $self->{fh}; + $self->_seekb($spos); + my $bytes_read = read $fh, my($data), $readsize; + $self->_seekb($dpos); + if ($data eq "") { + $self->_chop_file; + last; + } + $self->_write_record($data); + $spos += $bytes_read; + $dpos += $bytes_read; + $len -= $bytes_read if defined $len; + } +} + +# Write $data into a block of length $len at position $pos, +# moving everything in the block forwards to make room. +# Instead of writing the last length($data) bytes from the block +# (because there isn't room for them any longer) return them. +sub _downcopy { + my $blocksize = 8192; + my ($self, $data, $pos, $len) = @_; + my $fh = $self->{fh}; + + while (! defined $len || $len > 0) { + my $readsize = ! defined($len) ? $blocksize + : $len > $blocksize? $blocksize : $len; + $self->_seekb($pos); + read $fh, my($old), $readsize; + $data .= $old; + $self->_seekb($pos); + my $writable = substr($data, 0, $readsize, ""); + last if $writable eq ""; + $self->_write_record($writable); + $len -= $readsize if defined $len; + $pos += $readsize; + } + return $data; +} + +# Adjust the object data structures following an '_mtwrite' +# Arguments are +# [$pos, $nrecs, @length] items +# indicating that $nrecs records were removed at $recpos (a record offset) +# and replaced with records of length @length... +# Arguments guarantee that $recpos is strictly increasing. +# No return value +sub _oadjust { + my $self = shift; + my $delta = 0; + my $delta_recs = 0; + my $prev_end = -1; + my %newkeys; + + for (@_) { + my ($pos, $nrecs, @data) = @$_; + $pos += $delta_recs; + + # Adjust the offsets of the records after the previous batch up + # to the first new one of this batch + for my $i ($prev_end+2 .. $pos - 1) { + $self->{offsets}[$i] += $delta; + $newkey{$i} = $i + $delta_recs; + } + + $prev_end = $pos + @data - 1; # last record moved on this pass + + # Remove the offsets for the removed records; + # replace with the offsets for the inserted records + my @newoff = ($self->{offsets}[$pos] + $delta); + for my $i (0 .. $#data) { + my $newlen = length $data[$i]; + push @newoff, $newoff[$i] + $newlen; + $delta += $newlen; + } + + for my $i ($pos .. $pos+$nrecs-1) { + last if $i+1 > $#{$self->{offsets}}; + my $oldlen = $self->{offsets}[$i+1] - $self->{offsets}[$i]; + $delta -= $oldlen; + } + +# # also this data has changed, so update it in the cache +# for (0 .. $#data) { +# $self->{cache}->update($pos + $_, $data[$_]); +# } +# if ($delta_recs) { +# my @oldkeys = grep $_ >= $pos + @data, $self->{cache}->ckeys; +# my @newkeys = map $_ + $delta_recs, @oldkeys; +# $self->{cache}->rekey(\@oldkeys, \@newkeys); +# } + + # replace old offsets with new + splice @{$self->{offsets}}, $pos, $nrecs+1, @newoff; + # What if we just spliced out the end of the offsets table? + # shouldn't we clear $self->{eof}? Test for this XXX BUG TODO + + $delta_recs += @data - $nrecs; # net change in total number of records + } + + # The trailing records at the very end of the file + if ($delta) { + for my $i ($prev_end+2 .. $#{$self->{offsets}}) { + $self->{offsets}[$i] += $delta; + } + } + + # If we scrubbed out all known offsets, regenerate the trivial table + # that knows that the file does indeed start at 0. + $self->{offsets}[0] = 0 unless @{$self->{offsets}}; + # If the file got longer, the offsets table is no longer complete + # $self->{eof} = 0 if $delta_recs > 0; + + # Now there might be too much data in the cache, if we spliced out + # some short records and spliced in some long ones. If so, flush + # the cache. + $self->_cache_flush; +} + +# If a record does not already end with the appropriate terminator +# string, append one. +sub _fixrecs { + my $self = shift; + for (@_) { + $_ = "" unless defined $_; + $_ .= $self->{recsep} + unless substr($_, - $self->{recseplen}) eq $self->{recsep}; + } +} + + +################################################################ +# +# Basic read, write, and seek +# + +# seek to the beginning of record #$n +# Assumes that the offsets table is already correctly populated +# +# Note that $n=-1 has a special meaning here: It means the start of +# the last known record; this may or may not be the very last record +# in the file, depending on whether the offsets table is fully populated. +# +sub _seek { + my ($self, $n) = @_; + my $o = $self->{offsets}[$n]; + defined($o) + or confess("logic error: undefined offset for record $n"); + seek $self->{fh}, $o, SEEK_SET + or confess "Couldn't seek filehandle: $!"; # "Should never happen." +} + +# seek to byte $b in the file +sub _seekb { + my ($self, $b) = @_; + seek $self->{fh}, $b, SEEK_SET + or die "Couldn't seek filehandle: $!"; # "Should never happen." +} + +# populate the offsets table up to the beginning of record $n +# return the offset of record $n +sub _fill_offsets_to { + my ($self, $n) = @_; + + return $self->{offsets}[$n] if $self->{eof}; + + my $fh = $self->{fh}; + local *OFF = $self->{offsets}; + my $rec; + + until ($#OFF >= $n) { + $self->_seek(-1); # tricky -- see comment at _seek + $rec = $self->_read_record; + if (defined $rec) { + push @OFF, int(tell $fh); # Tels says that int() saves memory here + } else { + $self->{eof} = 1; + return; # It turns out there is no such record + } + } + + # we have now read all the records up to record n-1, + # so we can return the offset of record n + $OFF[$n]; +} + +sub _fill_offsets { + my ($self) = @_; + + my $fh = $self->{fh}; + local *OFF = $self->{offsets}; + + $self->_seek(-1); # tricky -- see comment at _seek + + # Tels says that inlining read_record() would make this loop + # five times faster. 20030508 + while ( defined $self->_read_record()) { + # int() saves us memory here + push @OFF, int(tell $fh); + } + + $self->{eof} = 1; + $#OFF; +} + +# assumes that $rec is already suitably terminated +sub _write_record { + my ($self, $rec) = @_; + my $fh = $self->{fh}; + local $\ = ""; + print $fh $rec + or die "Couldn't write record: $!"; # "Should never happen." +# $self->{_written} += length($rec); +} + +sub _read_record { + my $self = shift; + my $rec; + { no warnings 'uninitialized'; # so in-memory is free from the warning. + local $/ = $self->{recsep}; + my $fh = $self->{fh}; + $rec = <$fh>; + } + return unless defined $rec; + if (substr($rec, -$self->{recseplen}) ne $self->{recsep}) { + # improperly terminated final record --- quietly fix it. +# my $ac = substr($rec, -$self->{recseplen}); +# $ac =~ s/\n/\\n/g; + $self->{sawlastrec} = 1; + unless ($self->{rdonly}) { + local $\ = ""; + my $fh = $self->{fh}; + print $fh $self->{recsep}; + } + $rec .= $self->{recsep}; + } +# $self->{_read} += length($rec) if defined $rec; + $rec; +} + +sub _rw_stats { + my $self = shift; + @{$self}{'_read', '_written'}; +} + +################################################################ +# +# Read cache management + +sub _cache_flush { + my ($self) = @_; + $self->{cache}->reduce_size_to($self->{memory} - $self->{deferred_s}); +} + +sub _cache_too_full { + my $self = shift; + $self->{cache}->bytes + $self->{deferred_s} >= $self->{memory}; +} + +################################################################ +# +# File custodial services +# + + +# We have read to the end of the file and have the offsets table +# entirely populated. Now we need to write a new record beyond +# the end of the file. We prepare for this by writing +# empty records into the file up to the position we want +# +# assumes that the offsets table already contains the offset of record $n, +# if it exists, and extends to the end of the file if not. +sub _extend_file_to { + my ($self, $n) = @_; + $self->_seek(-1); # position after the end of the last record + my $pos = $self->{offsets}[-1]; + + # the offsets table has one entry more than the total number of records + my $extras = $n - $#{$self->{offsets}}; + + # Todo : just use $self->{recsep} x $extras here? + while ($extras-- > 0) { + $self->_write_record($self->{recsep}); + push @{$self->{offsets}}, int(tell $self->{fh}); + } +} + +# Truncate the file at the current position +sub _chop_file { + my $self = shift; + truncate $self->{fh}, tell($self->{fh}); +} + + +# compute the size of a buffer suitable for moving +# all the data in a file forward $n bytes +# ($n may be negative) +# The result should be at least $n. +sub _bufsize { + my $n = shift; + return 8192 if $n <= 0; + my $b = $n & ~8191; + $b += 8192 if $n & 8191; + $b; +} + +################################################################ +# +# Miscellaneous public methods +# + +# Lock the file +sub flock { + my ($self, $op) = @_; + unless (@_ <= 3) { + my $pack = ref $self; + croak "Usage: $pack\->flock([OPERATION])"; + } + my $fh = $self->{fh}; + $op = LOCK_EX unless defined $op; + my $locked = flock $fh, $op; + + if ($locked && ($op & (LOCK_EX | LOCK_SH))) { + # If you're locking the file, then presumably it's because + # there might have been a write access by another process. + # In that case, the read cache contents and the offsets table + # might be invalid, so discard them. 20030508 + $self->{offsets} = [0]; + $self->{cache}->empty; + } + + $locked; +} + +# Get/set autochomp option +sub autochomp { + my $self = shift; + if (@_) { + my $old = $self->{autochomp}; + $self->{autochomp} = shift; + $old; + } else { + $self->{autochomp}; + } +} + +# Get offset table entries; returns offset of nth record +sub offset { + my ($self, $n) = @_; + + if ($#{$self->{offsets}} < $n) { + return if $self->{eof}; # request for record beyond the end of file + my $o = $self->_fill_offsets_to($n); + # If it's still undefined, there is no such record, so return 'undef' + return unless defined $o; + } + + $self->{offsets}[$n]; +} + +sub discard_offsets { + my $self = shift; + $self->{offsets} = [0]; +} + +################################################################ +# +# Matters related to deferred writing +# + +# Defer writes +sub defer { + my $self = shift; + $self->_stop_autodeferring; + @{$self->{ad_history}} = (); + $self->{defer} = 1; +} + +# Flush deferred writes +# +# This could be better optimized to write the file in one pass, instead +# of one pass per block of records. But that will require modifications +# to _twrite, so I should have a good _twrite test suite first. +sub flush { + my $self = shift; + + $self->_flush; + $self->{defer} = 0; +} + +sub _old_flush { + my $self = shift; + my @writable = sort {$a<=>$b} (keys %{$self->{deferred}}); + + while (@writable) { + # gather all consecutive records from the front of @writable + my $first_rec = shift @writable; + my $last_rec = $first_rec+1; + ++$last_rec, shift @writable while @writable && $last_rec == $writable[0]; + --$last_rec; + $self->_fill_offsets_to($last_rec); + $self->_extend_file_to($last_rec); + $self->_splice($first_rec, $last_rec-$first_rec+1, + @{$self->{deferred}}{$first_rec .. $last_rec}); + } + + $self->_discard; # clear out defered-write-cache +} + +sub _flush { + my $self = shift; + my @writable = sort {$a<=>$b} (keys %{$self->{deferred}}); + my @args; + my @adjust; + + while (@writable) { + # gather all consecutive records from the front of @writable + my $first_rec = shift @writable; + my $last_rec = $first_rec+1; + ++$last_rec, shift @writable while @writable && $last_rec == $writable[0]; + --$last_rec; + my $end = $self->_fill_offsets_to($last_rec+1); + if (not defined $end) { + $self->_extend_file_to($last_rec); + $end = $self->{offsets}[$last_rec]; + } + my ($start) = $self->{offsets}[$first_rec]; + push @args, + join("", @{$self->{deferred}}{$first_rec .. $last_rec}), # data + $start, # position + $end-$start; # length + push @adjust, [$first_rec, # starting at this position... + $last_rec-$first_rec+1, # this many records... + # are replaced with these... + @{$self->{deferred}}{$first_rec .. $last_rec}, + ]; + } + + $self->_mtwrite(@args); # write multiple record groups + $self->_discard; # clear out defered-write-cache + $self->_oadjust(@adjust); +} + +# Discard deferred writes and disable future deferred writes +sub discard { + my $self = shift; + $self->_discard; + $self->{defer} = 0; +} + +# Discard deferred writes, but retain old deferred writing mode +sub _discard { + my $self = shift; + %{$self->{deferred}} = (); + $self->{deferred_s} = 0; + $self->{deferred_max} = -1; + $self->{cache}->set_limit($self->{memory}); +} + +# Deferred writing is enabled, either explicitly ($self->{defer}) +# or automatically ($self->{autodeferring}) +sub _is_deferring { + my $self = shift; + $self->{defer} || $self->{autodeferring}; +} + +# The largest record number of any deferred record +sub _defer_max { + my $self = shift; + return $self->{deferred_max} if defined $self->{deferred_max}; + my $max = -1; + for my $key (keys %{$self->{deferred}}) { + $max = $key if $key > $max; + } + $self->{deferred_max} = $max; + $max; +} + +################################################################ +# +# Matters related to autodeferment +# + +# Get/set autodefer option +sub autodefer { + my $self = shift; + if (@_) { + my $old = $self->{autodefer}; + $self->{autodefer} = shift; + if ($old) { + $self->_stop_autodeferring; + @{$self->{ad_history}} = (); + } + $old; + } else { + $self->{autodefer}; + } +} + +# The user is trying to store record #$n Record that in the history, +# and then enable (or disable) autodeferment if that seems useful. +# Note that it's OK for $n to be a non-number, as long as the function +# is prepared to deal with that. Nobody else looks at the ad_history. +# +# Now, what does the ad_history mean, and what is this function doing? +# Essentially, the idea is to enable autodeferring when we see that the +# user has made three consecutive STORE calls to three consecutive records. +# ("Three" is actually ->{autodefer_threshhold}.) +# A STORE call for record #$n inserts $n into the autodefer history, +# and if the history contains three consecutive records, we enable +# autodeferment. An ad_history of [X, Y] means that the most recent +# STOREs were for records X, X+1, ..., Y, in that order. +# +# Inserting a nonconsecutive number erases the history and starts over. +# +# Performing a special operation like SPLICE erases the history. +# +# There's one special case: CLEAR means that CLEAR was just called. +# In this case, we prime the history with [-2, -1] so that if the next +# write is for record 0, autodeferring goes on immediately. This is for +# the common special case of "@a = (...)". +# +sub _annotate_ad_history { + my ($self, $n) = @_; + return unless $self->{autodefer}; # feature is disabled + return if $self->{defer}; # already in explicit defer mode + return unless $self->{offsets}[-1] >= $self->{autodefer_filelen_threshhold}; + + local *H = $self->{ad_history}; + if ($n eq 'CLEAR') { + @H = (-2, -1); # prime the history with fake records + $self->_stop_autodeferring; + } elsif ($n =~ /^\d+$/) { + if (@H == 0) { + @H = ($n, $n); + } else { # @H == 2 + if ($H[1] == $n-1) { # another consecutive record + $H[1]++; + if ($H[1] - $H[0] + 1 >= $self->{autodefer_threshhold}) { + $self->{autodeferring} = 1; + } + } else { # nonconsecutive- erase and start over + @H = ($n, $n); + $self->_stop_autodeferring; + } + } + } else { # SPLICE or STORESIZE or some such + @H = (); + $self->_stop_autodeferring; + } +} + +# If autodeferring was enabled, cut it out and discard the history +sub _stop_autodeferring { + my $self = shift; + if ($self->{autodeferring}) { + $self->_flush; + } + $self->{autodeferring} = 0; +} + +################################################################ + + +# This is NOT a method. It is here for two reasons: +# 1. To factor a fairly complicated block out of the constructor +# 2. To provide access for the test suite, which need to be sure +# files are being written properly. +sub _default_recsep { + my $recsep = $/; + if ($^O eq 'MSWin32') { # Dos too? + # Windows users expect files to be terminated with \r\n + # But $/ is set to \n instead + # Note that this also transforms \n\n into \r\n\r\n. + # That is a feature. + $recsep =~ s/\n/\r\n/g; + } + $recsep; +} + +# Utility function for _check_integrity +sub _ci_warn { + my $msg = shift; + $msg =~ s/\n/\\n/g; + $msg =~ s/\r/\\r/g; + print "# $msg\n"; +} + +# Given a file, make sure the cache is consistent with the +# file contents and the internal data structures are consistent with +# each other. Returns true if everything checks out, false if not +# +# The $file argument is no longer used. It is retained for compatibility +# with the existing test suite. +sub _check_integrity { + my ($self, $file, $warn) = @_; + my $rsl = $self->{recseplen}; + my $rs = $self->{recsep}; + my $good = 1; + local *_; # local $_ does not work here + local $DIAGNOSTIC = 1; + + if (not defined $rs) { + _ci_warn("recsep is undef!"); + $good = 0; + } elsif ($rs eq "") { + _ci_warn("recsep is empty!"); + $good = 0; + } elsif ($rsl != length $rs) { + my $ln = length $rs; + _ci_warn("recsep <$rs> has length $ln, should be $rsl"); + $good = 0; + } + + if (not defined $self->{offsets}[0]) { + _ci_warn("offset 0 is missing!"); + $good = 0; + + } elsif ($self->{offsets}[0] != 0) { + _ci_warn("rec 0: offset <$self->{offsets}[0]> s/b 0!"); + $good = 0; + } + + my $cached = 0; + { + local *F = $self->{fh}; + seek F, 0, SEEK_SET; + local $. = 0; + local $/ = $rs; + + while () { + my $n = $. - 1; + my $cached = $self->{cache}->_produce($n); + my $offset = $self->{offsets}[$.]; + my $ao = tell F; + if (defined $offset && $offset != $ao) { + _ci_warn("rec $n: offset <$offset> actual <$ao>"); + $good = 0; + } + if (defined $cached && $_ ne $cached && ! $self->{deferred}{$n}) { + $good = 0; + _ci_warn("rec $n: cached <$cached> actual <$_>"); + } + if (defined $cached && substr($cached, -$rsl) ne $rs) { + $good = 0; + _ci_warn("rec $n in the cache is missing the record separator"); + } + if (! defined $offset && $self->{eof}) { + $good = 0; + _ci_warn("The offset table was marked complete, but it is missing element $."); + } + } + if (@{$self->{offsets}} > $.+1) { + $good = 0; + my $n = @{$self->{offsets}}; + _ci_warn("The offset table has $n items, but the file has only $."); + } + + my $deferring = $self->_is_deferring; + for my $n ($self->{cache}->ckeys) { + my $r = $self->{cache}->_produce($n); + $cached += length($r); + next if $n+1 <= $.; # checked this already + _ci_warn("spurious caching of record $n"); + $good = 0; + } + my $b = $self->{cache}->bytes; + if ($cached != $b) { + _ci_warn("cache size is $b, should be $cached"); + $good = 0; + } + } + + # That cache has its own set of tests + $good = 0 unless $self->{cache}->_check_integrity; + + # Now let's check the deferbuffer + # Unless deferred writing is enabled, it should be empty + if (! $self->_is_deferring && %{$self->{deferred}}) { + _ci_warn("deferred writing disabled, but deferbuffer nonempty"); + $good = 0; + } + + # Any record in the deferbuffer should *not* be present in the readcache + my $deferred_s = 0; + while (my ($n, $r) = each %{$self->{deferred}}) { + $deferred_s += length($r); + if (defined $self->{cache}->_produce($n)) { + _ci_warn("record $n is in the deferbuffer *and* the readcache"); + $good = 0; + } + if (substr($r, -$rsl) ne $rs) { + _ci_warn("rec $n in the deferbuffer is missing the record separator"); + $good = 0; + } + } + + # Total size of deferbuffer should match internal total + if ($deferred_s != $self->{deferred_s}) { + _ci_warn("buffer size is $self->{deferred_s}, should be $deferred_s"); + $good = 0; + } + + # Total size of deferbuffer should not exceed the specified limit + if ($deferred_s > $self->{dw_size}) { + _ci_warn("buffer size is $self->{deferred_s} which exceeds the limit of $self->{dw_size}"); + $good = 0; + } + + # Total size of cached data should not exceed the specified limit + if ($deferred_s + $cached > $self->{memory}) { + my $total = $deferred_s + $cached; + _ci_warn("total stored data size is $total which exceeds the limit of $self->{memory}"); + $good = 0; + } + + # Stuff related to autodeferment + if (!$self->{autodefer} && @{$self->{ad_history}}) { + _ci_warn("autodefer is disabled, but ad_history is nonempty"); + $good = 0; + } + if ($self->{autodeferring} && $self->{defer}) { + _ci_warn("both autodeferring and explicit deferring are active"); + $good = 0; + } + if (@{$self->{ad_history}} == 0) { + # That's OK, no additional tests required + } elsif (@{$self->{ad_history}} == 2) { + my @non_number = grep !/^-?\d+$/, @{$self->{ad_history}}; + if (@non_number) { + my $msg; + { local $" = ')('; + $msg = "ad_history contains non-numbers (@{$self->{ad_history}})"; + } + _ci_warn($msg); + $good = 0; + } elsif ($self->{ad_history}[1] < $self->{ad_history}[0]) { + _ci_warn("ad_history has nonsensical values @{$self->{ad_history}}"); + $good = 0; + } + } else { + _ci_warn("ad_history has bad length <@{$self->{ad_history}}>"); + $good = 0; + } + + $good; +} + +################################################################ +# +# Tie::File::Cache +# +# Read cache + +package Tie::File::Cache; +$Tie::File::Cache::VERSION = $Tie::File::VERSION; +use Carp ':DEFAULT', 'confess'; + +sub HEAP () { 0 } +sub HASH () { 1 } +sub MAX () { 2 } +sub BYTES() { 3 } +#sub STAT () { 4 } # Array with request statistics for each record +#sub MISS () { 5 } # Total number of cache misses +#sub REQ () { 6 } # Total number of cache requests +use strict 'vars'; + +sub new { + my ($pack, $max) = @_; + local *_; + croak "missing argument to ->new" unless defined $max; + my $self = []; + bless $self => $pack; + @$self = (Tie::File::Heap->new($self), {}, $max, 0); + $self; +} + +sub adj_limit { + my ($self, $n) = @_; + $self->[MAX] += $n; +} + +sub set_limit { + my ($self, $n) = @_; + $self->[MAX] = $n; +} + +# For internal use only +# Will be called by the heap structure to notify us that a certain +# piece of data has moved from one heap element to another. +# $k is the hash key of the item +# $n is the new index into the heap at which it is stored +# If $n is undefined, the item has been removed from the heap. +sub _heap_move { + my ($self, $k, $n) = @_; + if (defined $n) { + $self->[HASH]{$k} = $n; + } else { + delete $self->[HASH]{$k}; + } +} + +sub insert { + my ($self, $key, $val) = @_; + local *_; + croak "missing argument to ->insert" unless defined $key; + unless (defined $self->[MAX]) { + confess "undefined max" ; + } + confess "undefined val" unless defined $val; + return if length($val) > $self->[MAX]; + +# if ($self->[STAT]) { +# $self->[STAT][$key] = 1; +# return; +# } + + my $oldnode = $self->[HASH]{$key}; + if (defined $oldnode) { + my $oldval = $self->[HEAP]->set_val($oldnode, $val); + $self->[BYTES] -= length($oldval); + } else { + $self->[HEAP]->insert($key, $val); + } + $self->[BYTES] += length($val); + $self->flush if $self->[BYTES] > $self->[MAX]; +} + +sub expire { + my $self = shift; + my $old_data = $self->[HEAP]->popheap; + return unless defined $old_data; + $self->[BYTES] -= length $old_data; + $old_data; +} + +sub remove { + my ($self, @keys) = @_; + my @result; + +# if ($self->[STAT]) { +# for my $key (@keys) { +# $self->[STAT][$key] = 0; +# } +# return; +# } + + for my $key (@keys) { + next unless exists $self->[HASH]{$key}; + my $old_data = $self->[HEAP]->remove($self->[HASH]{$key}); + $self->[BYTES] -= length $old_data; + push @result, $old_data; + } + @result; +} + +sub lookup { + my ($self, $key) = @_; + local *_; + croak "missing argument to ->lookup" unless defined $key; + +# if ($self->[STAT]) { +# $self->[MISS]++ if $self->[STAT][$key]++ == 0; +# $self->[REQ]++; +# my $hit_rate = 1 - $self->[MISS] / $self->[REQ]; +# # Do some testing to determine this threshhold +# $#$self = STAT - 1 if $hit_rate > 0.20; +# } + + if (exists $self->[HASH]{$key}) { + $self->[HEAP]->lookup($self->[HASH]{$key}); + } else { + return; + } +} + +# For internal use only +sub _produce { + my ($self, $key) = @_; + my $loc = $self->[HASH]{$key}; + return unless defined $loc; + $self->[HEAP][$loc][2]; +} + +# For internal use only +sub _promote { + my ($self, $key) = @_; + $self->[HEAP]->promote($self->[HASH]{$key}); +} + +sub empty { + my ($self) = @_; + %{$self->[HASH]} = (); + $self->[BYTES] = 0; + $self->[HEAP]->empty; +# @{$self->[STAT]} = (); +# $self->[MISS] = 0; +# $self->[REQ] = 0; +} + +sub is_empty { + my ($self) = @_; + keys %{$self->[HASH]} == 0; +} + +sub update { + my ($self, $key, $val) = @_; + local *_; + croak "missing argument to ->update" unless defined $key; + if (length($val) > $self->[MAX]) { + my ($oldval) = $self->remove($key); + $self->[BYTES] -= length($oldval) if defined $oldval; + } elsif (exists $self->[HASH]{$key}) { + my $oldval = $self->[HEAP]->set_val($self->[HASH]{$key}, $val); + $self->[BYTES] += length($val); + $self->[BYTES] -= length($oldval) if defined $oldval; + } else { + $self->[HEAP]->insert($key, $val); + $self->[BYTES] += length($val); + } + $self->flush; +} + +sub rekey { + my ($self, $okeys, $nkeys) = @_; + local *_; + my %map; + @map{@$okeys} = @$nkeys; + croak "missing argument to ->rekey" unless defined $nkeys; + croak "length mismatch in ->rekey arguments" unless @$nkeys == @$okeys; + my %adjusted; # map new keys to heap indices + # You should be able to cut this to one loop TODO XXX + for (0 .. $#$okeys) { + $adjusted{$nkeys->[$_]} = delete $self->[HASH]{$okeys->[$_]}; + } + while (my ($nk, $ix) = each %adjusted) { + # @{$self->[HASH]}{keys %adjusted} = values %adjusted; + $self->[HEAP]->rekey($ix, $nk); + $self->[HASH]{$nk} = $ix; + } +} + +sub ckeys { + my $self = shift; + my @a = keys %{$self->[HASH]}; + @a; +} + +# Return total amount of cached data +sub bytes { + my $self = shift; + $self->[BYTES]; +} + +# Expire oldest item from cache until cache size is smaller than $max +sub reduce_size_to { + my ($self, $max) = @_; + until ($self->[BYTES] <= $max) { + # Note that Tie::File::Cache::expire has been inlined here + my $old_data = $self->[HEAP]->popheap; + return unless defined $old_data; + $self->[BYTES] -= length $old_data; + } +} + +# Why not just $self->reduce_size_to($self->[MAX])? +# Try this when things stabilize TODO XXX +# If the cache is too full, expire the oldest records +sub flush { + my $self = shift; + $self->reduce_size_to($self->[MAX]) if $self->[BYTES] > $self->[MAX]; +} + +# For internal use only +sub _produce_lru { + my $self = shift; + $self->[HEAP]->expire_order; +} + +BEGIN { *_ci_warn = \&Tie::File::_ci_warn } + +sub _check_integrity { # For CACHE + my $self = shift; + my $good = 1; + + # Test HEAP + $self->[HEAP]->_check_integrity or $good = 0; + + # Test HASH + my $bytes = 0; + for my $k (keys %{$self->[HASH]}) { + if ($k ne '0' && $k !~ /^[1-9][0-9]*$/) { + $good = 0; + _ci_warn "Cache hash key <$k> is non-numeric"; + } + + my $h = $self->[HASH]{$k}; + if (! defined $h) { + $good = 0; + _ci_warn "Heap index number for key $k is undefined"; + } elsif ($h == 0) { + $good = 0; + _ci_warn "Heap index number for key $k is zero"; + } else { + my $j = $self->[HEAP][$h]; + if (! defined $j) { + $good = 0; + _ci_warn "Heap contents key $k (=> $h) are undefined"; + } else { + $bytes += length($j->[2]); + if ($k ne $j->[1]) { + $good = 0; + _ci_warn "Heap contents key $k (=> $h) is $j->[1], should be $k"; + } + } + } + } + + # Test BYTES + if ($bytes != $self->[BYTES]) { + $good = 0; + _ci_warn "Total data in cache is $bytes, expected $self->[BYTES]"; + } + + # Test MAX + if ($bytes > $self->[MAX]) { + $good = 0; + _ci_warn "Total data in cache is $bytes, exceeds maximum $self->[MAX]"; + } + + return $good; +} + +sub delink { + my $self = shift; + $self->[HEAP] = undef; # Bye bye heap +} + +################################################################ +# +# Tie::File::Heap +# +# Heap data structure for use by cache LRU routines + +package Tie::File::Heap; +use Carp ':DEFAULT', 'confess'; +$Tie::File::Heap::VERSION = $Tie::File::Cache::VERSION; +sub SEQ () { 0 }; +sub KEY () { 1 }; +sub DAT () { 2 }; + +sub new { + my ($pack, $cache) = @_; + die "$pack: Parent cache object $cache does not support _heap_move method" + unless eval { $cache->can('_heap_move') }; + my $self = [[0,$cache,0]]; + bless $self => $pack; +} + +# Allocate a new sequence number, larger than all previously allocated numbers +sub _nseq { + my $self = shift; + $self->[0][0]++; +} + +sub _cache { + my $self = shift; + $self->[0][1]; +} + +sub _nelts { + my $self = shift; + $self->[0][2]; +} + +sub _nelts_inc { + my $self = shift; + ++$self->[0][2]; +} + +sub _nelts_dec { + my $self = shift; + --$self->[0][2]; +} + +sub is_empty { + my $self = shift; + $self->_nelts == 0; +} + +sub empty { + my $self = shift; + $#$self = 0; + $self->[0][2] = 0; + $self->[0][0] = 0; # might as well reset the sequence numbers +} + +# notify the parent cache object that we moved something +sub _heap_move { + my $self = shift; + $self->_cache->_heap_move(@_); +} + +# Insert a piece of data into the heap with the indicated sequence number. +# The item with the smallest sequence number is always at the top. +# If no sequence number is specified, allocate a new one and insert the +# item at the bottom. +sub insert { + my ($self, $key, $data, $seq) = @_; + $seq = $self->_nseq unless defined $seq; + $self->_insert_new([$seq, $key, $data]); +} + +# Insert a new, fresh item at the bottom of the heap +sub _insert_new { + my ($self, $item) = @_; + my $i = @$self; + $i = int($i/2) until defined $self->[$i/2]; + $self->[$i] = $item; + $self->[0][1]->_heap_move($self->[$i][KEY], $i); + $self->_nelts_inc; +} + +# Insert [$data, $seq] pair at or below item $i in the heap. +# If $i is omitted, default to 1 (the top element.) +sub _insert { + my ($self, $item, $i) = @_; +# $self->_check_loc($i) if defined $i; + $i = 1 unless defined $i; + until (! defined $self->[$i]) { + if ($self->[$i][SEQ] > $item->[SEQ]) { # inserted item is older + ($self->[$i], $item) = ($item, $self->[$i]); + $self->[0][1]->_heap_move($self->[$i][KEY], $i); + } + # If either is undefined, go that way. Otherwise, choose at random + my $dir; + $dir = 0 if !defined $self->[2*$i]; + $dir = 1 if !defined $self->[2*$i+1]; + $dir = int(rand(2)) unless defined $dir; + $i = 2*$i + $dir; + } + $self->[$i] = $item; + $self->[0][1]->_heap_move($self->[$i][KEY], $i); + $self->_nelts_inc; +} + +# Remove the item at node $i from the heap, moving child items upwards. +# The item with the smallest sequence number is always at the top. +# Moving items upwards maintains this condition. +# Return the removed item. Return undef if there was no item at node $i. +sub remove { + my ($self, $i) = @_; + $i = 1 unless defined $i; + my $top = $self->[$i]; + return unless defined $top; + while (1) { + my $ii; + my ($L, $R) = (2*$i, 2*$i+1); + + # If either is undefined, go the other way. + # Otherwise, go towards the smallest. + last unless defined $self->[$L] || defined $self->[$R]; + $ii = $R if not defined $self->[$L]; + $ii = $L if not defined $self->[$R]; + unless (defined $ii) { + $ii = $self->[$L][SEQ] < $self->[$R][SEQ] ? $L : $R; + } + + $self->[$i] = $self->[$ii]; # Promote child to fill vacated spot + $self->[0][1]->_heap_move($self->[$i][KEY], $i); + $i = $ii; # Fill new vacated spot + } + $self->[0][1]->_heap_move($top->[KEY], undef); + undef $self->[$i]; + $self->_nelts_dec; + return $top->[DAT]; +} + +sub popheap { + my $self = shift; + $self->remove(1); +} + +# set the sequence number of the indicated item to a higher number +# than any other item in the heap, and bubble the item down to the +# bottom. +sub promote { + my ($self, $n) = @_; +# $self->_check_loc($n); + $self->[$n][SEQ] = $self->_nseq; + my $i = $n; + while (1) { + my ($L, $R) = (2*$i, 2*$i+1); + my $dir; + last unless defined $self->[$L] || defined $self->[$R]; + $dir = $R unless defined $self->[$L]; + $dir = $L unless defined $self->[$R]; + unless (defined $dir) { + $dir = $self->[$L][SEQ] < $self->[$R][SEQ] ? $L : $R; + } + @{$self}[$i, $dir] = @{$self}[$dir, $i]; + for ($i, $dir) { + $self->[0][1]->_heap_move($self->[$_][KEY], $_) if defined $self->[$_]; + } + $i = $dir; + } +} + +# Return item $n from the heap, promoting its LRU status +sub lookup { + my ($self, $n) = @_; +# $self->_check_loc($n); + my $val = $self->[$n]; + $self->promote($n); + $val->[DAT]; +} + + +# Assign a new value for node $n, promoting it to the bottom of the heap +sub set_val { + my ($self, $n, $val) = @_; +# $self->_check_loc($n); + my $oval = $self->[$n][DAT]; + $self->[$n][DAT] = $val; + $self->promote($n); + return $oval; +} + +# The hask key has changed for an item; +# alter the heap's record of the hash key +sub rekey { + my ($self, $n, $new_key) = @_; +# $self->_check_loc($n); + $self->[$n][KEY] = $new_key; +} + +sub _check_loc { + my ($self, $n) = @_; + unless (1 || defined $self->[$n]) { + confess "_check_loc($n) failed"; + } +} + +BEGIN { *_ci_warn = \&Tie::File::_ci_warn } + +sub _check_integrity { + my $self = shift; + my $good = 1; + my %seq; + + unless (eval {$self->[0][1]->isa("Tie::File::Cache")}) { + _ci_warn "Element 0 of heap corrupt"; + $good = 0; + } + $good = 0 unless $self->_satisfies_heap_condition(1); + for my $i (2 .. $#{$self}) { + my $p = int($i/2); # index of parent node + if (defined $self->[$i] && ! defined $self->[$p]) { + _ci_warn "Element $i of heap defined, but parent $p isn't"; + $good = 0; + } + + if (defined $self->[$i]) { + if ($seq{$self->[$i][SEQ]}) { + my $seq = $self->[$i][SEQ]; + _ci_warn "Nodes $i and $seq{$seq} both have SEQ=$seq"; + $good = 0; + } else { + $seq{$self->[$i][SEQ]} = $i; + } + } + } + + return $good; +} + +sub _satisfies_heap_condition { + my $self = shift; + my $n = shift || 1; + my $good = 1; + for (0, 1) { + my $c = $n*2 + $_; + next unless defined $self->[$c]; + if ($self->[$n][SEQ] >= $self->[$c]) { + _ci_warn "Node $n of heap does not predate node $c"; + $good = 0 ; + } + $good = 0 unless $self->_satisfies_heap_condition($c); + } + return $good; +} + +# Return a list of all the values, sorted by expiration order +sub expire_order { + my $self = shift; + my @nodes = sort {$a->[SEQ] <=> $b->[SEQ]} $self->_nodes; + map { $_->[KEY] } @nodes; +} + +sub _nodes { + my $self = shift; + my $i = shift || 1; + return unless defined $self->[$i]; + ($self->[$i], $self->_nodes($i*2), $self->_nodes($i*2+1)); +} + +"Cogito, ergo sum."; # don't forget to return a true value from the file + +__END__ + +=head1 NAME + +Tie::File - Access the lines of a disk file via a Perl array + +=head1 SYNOPSIS + + # This file documents Tie::File version 0.96 + use Tie::File; + + tie @array, 'Tie::File', filename or die ...; + + $array[13] = 'blah'; # line 13 of the file is now 'blah' + print $array[42]; # display line 42 of the file + + $n_recs = @array; # how many records are in the file? + $#array -= 2; # chop two records off the end + + + for (@array) { + s/PERL/Perl/g; # Replace PERL with Perl everywhere in the file + } + + # These are just like regular push, pop, unshift, shift, and splice + # Except that they modify the file in the way you would expect + + push @array, new recs...; + my $r1 = pop @array; + unshift @array, new recs...; + my $r2 = shift @array; + @old_recs = splice @array, 3, 7, new recs...; + + untie @array; # all finished + + +=head1 DESCRIPTION + +C represents a regular text file as a Perl array. Each +element in the array corresponds to a record in the file. The first +line of the file is element 0 of the array; the second line is element +1, and so on. + +The file is I loaded into memory, so this will work even for +gigantic files. + +Changes to the array are reflected in the file immediately. + +Lazy people and beginners may now stop reading the manual. + +=head2 In-Memory File + +Perl 5.8 adds support to in-memory file and Tie::File 0.97 and higher +makes use of this feature when you pass C to the filenname. + +Though not time-efficient, you may save memory if the average size of +array element is 20 bytes or less. This case is typical when the +array contains only numbers. + +In practice, you should consider using L, L +and so forth instead of Tie::File since these are more optimezed for +in-memory storage. But for TMTOWTDI's sake and the tribute to Late +Nick Ing-Simmons who added PerlIO on which in-memmory file is +suppoted, I have added this feature (dankogai) + +=head2 C + +What is a 'record'? By default, the meaning is the same as for the +C...E> operator: It's a string terminated by C<$/>, which is +probably C<"\n">. (Minor exception: on DOS and Win32 systems, a +'record' is a string terminated by C<"\r\n">.) You may change the +definition of "record" by supplying the C option in the C +call: + + tie @array, 'Tie::File', $file, recsep => 'es'; + +This says that records are delimited by the string C. If the file +contained the following data: + + Curse these pesky flies!\n + +then the C<@array> would appear to have four elements: + + "Curse th" + "e p" + "ky fli" + "!\n" + +An undefined value is not permitted as a record separator. Perl's +special "paragraph mode" semantics (E la C<$/ = "">) are not +emulated. + +Records read from the tied array do not have the record separator +string on the end; this is to allow + + $array[17] .= "extra"; + +to work as expected. + +(See L<"autochomp">, below.) Records stored into the array will have +the record separator string appended before they are written to the +file, if they don't have one already. For example, if the record +separator string is C<"\n">, then the following two lines do exactly +the same thing: + + $array[17] = "Cherry pie"; + $array[17] = "Cherry pie\n"; + +The result is that the contents of line 17 of the file will be +replaced with "Cherry pie"; a newline character will separate line 17 +from line 18. This means that this code will do nothing: + + chomp $array[17]; + +Because the Ced value will have the separator reattached when +it is written back to the file. There is no way to create a file +whose trailing record separator string is missing. + +Inserting records that I the record separator string is not +supported by this module. It will probably produce a reasonable +result, but what this result will be may change in a future version. +Use 'splice' to insert records or to replace one record with several. + +=head2 C + +Normally, array elements have the record separator removed, so that if +the file contains the text + + Gold + Frankincense + Myrrh + +the tied array will appear to contain C<("Gold", "Frankincense", +"Myrrh")>. If you set C to a false value, the record +separator will not be removed. If the file above was tied with + + tie @gifts, "Tie::File", $gifts, autochomp => 0; + +then the array C<@gifts> would appear to contain C<("Gold\n", +"Frankincense\n", "Myrrh\n")>, or (on Win32 systems) C<("Gold\r\n", +"Frankincense\r\n", "Myrrh\r\n")>. + +=head2 C + +Normally, the specified file will be opened for read and write access, +and will be created if it does not exist. (That is, the flags +C are supplied in the C call.) If you want to +change this, you may supply alternative flags in the C option. +See L for a listing of available flags. +For example: + + # open the file if it exists, but fail if it does not exist + use Fcntl 'O_RDWR'; + tie @array, 'Tie::File', $file, mode => O_RDWR; + + # create the file if it does not exist + use Fcntl 'O_RDWR', 'O_CREAT'; + tie @array, 'Tie::File', $file, mode => O_RDWR | O_CREAT; + + # open an existing file in read-only mode + use Fcntl 'O_RDONLY'; + tie @array, 'Tie::File', $file, mode => O_RDONLY; + +Opening the data file in write-only or append mode is not supported. + +=head2 C + +This is an upper limit on the amount of memory that C will +consume at any time while managing the file. This is used for two +things: managing the I and managing the I. + +Records read in from the file are cached, to avoid having to re-read +them repeatedly. If you read the same record twice, the first time it +will be stored in memory, and the second time it will be fetched from +the I. The amount of data in the read cache will not +exceed the value you specified for C. If C wants +to cache a new record, but the read cache is full, it will make room +by expiring the least-recently visited records from the read cache. + +The default memory limit is 2Mib. You can adjust the maximum read +cache size by supplying the C option. The argument is the +desired cache size, in bytes. + + # I have a lot of memory, so use a large cache to speed up access + tie @array, 'Tie::File', $file, memory => 20_000_000; + +Setting the memory limit to 0 will inhibit caching; records will be +fetched from disk every time you examine them. + +The C value is not an absolute or exact limit on the memory +used. C objects contains some structures besides the read +cache and the deferred write buffer, whose sizes are not charged +against C. + +The cache itself consumes about 310 bytes per cached record, so if +your file has many short records, you may want to decrease the cache +memory limit, or else the cache overhead may exceed the size of the +cached data. + + +=head2 C + +(This is an advanced feature. Skip this section on first reading.) + +If you use deferred writing (See L<"Deferred Writing">, below) then +data you write into the array will not be written directly to the +file; instead, it will be saved in the I to be +written out later. Data in the deferred write buffer is also charged +against the memory limit you set with the C option. + +You may set the C option to limit the amount of data that can +be saved in the deferred write buffer. This limit may not exceed the +total memory limit. For example, if you set C to 1000 and +C to 2500, that means that no more than 1000 bytes of deferred +writes will be saved up. The space available for the read cache will +vary, but it will always be at least 1500 bytes (if the deferred write +buffer is full) and it could grow as large as 2500 bytes (if the +deferred write buffer is empty.) + +If you don't specify a C, it defaults to the entire memory +limit. + +=head2 Option Format + +C<-mode> is a synonym for C. C<-recsep> is a synonym for +C. C<-memory> is a synonym for C. You get the +idea. + +=head1 Public Methods + +The C call returns an object, say C<$o>. You may call + + $rec = $o->FETCH($n); + $o->STORE($n, $rec); + +to fetch or store the record at line C<$n>, respectively; similarly +the other tied array methods. (See L for details.) You may +also call the following methods on this object: + +=head2 C + + $o->flock(MODE) + +will lock the tied file. C has the same meaning as the second +argument to the Perl built-in C function; for example +C or C. (These constants are provided by +the C declaration.) + +C is optional; the default is C. + +C maintains an internal table of the byte offset of each +record it has seen in the file. + +When you use C to lock the file, C assumes that the +read cache is no longer trustworthy, because another process might +have modified the file since the last time it was read. Therefore, a +successful call to C discards the contents of the read cache +and the internal record offset table. + +C promises that the following sequence of operations will +be safe: + + my $o = tie @array, "Tie::File", $filename; + $o->flock; + +In particular, C will I read or write the file during +the C call. (Exception: Using C O_TRUNC> will, of +course, erase the file during the C call. If you want to do this +safely, then open the file without C, lock the file, and use +C<@array = ()>.) + +The best way to unlock a file is to discard the object and untie the +array. It is probably unsafe to unlock the file without also untying +it, because if you do, changes may remain unwritten inside the object. +That is why there is no shortcut for unlocking. If you really want to +unlock the file prematurely, you know what to do; if you don't know +what to do, then don't do it. + +All the usual warnings about file locking apply here. In particular, +note that file locking in Perl is B, which means that +holding a lock will not prevent anyone else from reading, writing, or +erasing the file; it only prevents them from getting another lock at +the same time. Locks are analogous to green traffic lights: If you +have a green light, that does not prevent the idiot coming the other +way from plowing into you sideways; it merely guarantees to you that +the idiot does not also have a green light at the same time. + +=head2 C + + my $old_value = $o->autochomp(0); # disable autochomp option + my $old_value = $o->autochomp(1); # enable autochomp option + + my $ac = $o->autochomp(); # recover current value + +See L<"autochomp">, above. + +=head2 C, C, C, and C + +See L<"Deferred Writing">, below. + +=head2 C + + $off = $o->offset($n); + +This method returns the byte offset of the start of the C<$n>th record +in the file. If there is no such record, it returns an undefined +value. + +=head1 Tying to an already-opened filehandle + +If C<$fh> is a filehandle, such as is returned by C or one +of the other C modules, you may use: + + tie @array, 'Tie::File', $fh, ...; + +Similarly if you opened that handle C with regular C or +C, you may use: + + tie @array, 'Tie::File', \*FH, ...; + +Handles that were opened write-only won't work. Handles that were +opened read-only will work as long as you don't try to modify the +array. Handles must be attached to seekable sources of data---that +means no pipes or sockets. If C can detect that you +supplied a non-seekable handle, the C call will throw an +exception. (On Unix systems, it can detect this.) + +Note that Tie::File will only close any filehandles that it opened +internally. If you passed it a filehandle as above, you "own" the +filehandle, and are responsible for closing it after you have untied +the @array. + +=head1 Deferred Writing + +(This is an advanced feature. Skip this section on first reading.) + +Normally, modifying a C array writes to the underlying file +immediately. Every assignment like C<$a[3] = ...> rewrites as much of +the file as is necessary; typically, everything from line 3 through +the end will need to be rewritten. This is the simplest and most +transparent behavior. Performance even for large files is reasonably +good. + +However, under some circumstances, this behavior may be excessively +slow. For example, suppose you have a million-record file, and you +want to do: + + for (@FILE) { + $_ = "> $_"; + } + +The first time through the loop, you will rewrite the entire file, +from line 0 through the end. The second time through the loop, you +will rewrite the entire file from line 1 through the end. The third +time through the loop, you will rewrite the entire file from line 2 to +the end. And so on. + +If the performance in such cases is unacceptable, you may defer the +actual writing, and then have it done all at once. The following loop +will perform much better for large files: + + (tied @a)->defer; + for (@a) { + $_ = "> $_"; + } + (tied @a)->flush; + +If C's memory limit is large enough, all the writing will +done in memory. Then, when you call C<-Eflush>, the entire file +will be rewritten in a single pass. + +(Actually, the preceding discussion is something of a fib. You don't +need to enable deferred writing to get good performance for this +common case, because C will do it for you automatically +unless you specifically tell it not to. See L<"autodeferring">, +below.) + +Calling C<-Eflush> returns the array to immediate-write mode. If +you wish to discard the deferred writes, you may call C<-Ediscard> +instead of C<-Eflush>. Note that in some cases, some of the data +will have been written already, and it will be too late for +C<-Ediscard> to discard all the changes. Support for +C<-Ediscard> may be withdrawn in a future version of C. + +Deferred writes are cached in memory up to the limit specified by the +C option (see above). If the deferred-write buffer is full +and you try to write still more deferred data, the buffer will be +flushed. All buffered data will be written immediately, the buffer +will be emptied, and the now-empty space will be used for future +deferred writes. + +If the deferred-write buffer isn't yet full, but the total size of the +buffer and the read cache would exceed the C limit, the oldest +records will be expired from the read cache until the total size is +under the limit. + +C, C, C, C, and C cannot be +deferred. When you perform one of these operations, any deferred data +is written to the file and the operation is performed immediately. +This may change in a future version. + +If you resize the array with deferred writing enabled, the file will +be resized immediately, but deferred records will not be written. +This has a surprising consequence: C<@a = (...)> erases the file +immediately, but the writing of the actual data is deferred. This +might be a bug. If it is a bug, it will be fixed in a future version. + +=head2 Autodeferring + +C tries to guess when deferred writing might be helpful, +and to turn it on and off automatically. + + for (@a) { + $_ = "> $_"; + } + +In this example, only the first two assignments will be done +immediately; after this, all the changes to the file will be deferred +up to the user-specified memory limit. + +You should usually be able to ignore this and just use the module +without thinking about deferring. However, special applications may +require fine control over which writes are deferred, or may require +that all writes be immediate. To disable the autodeferment feature, +use + + (tied @o)->autodefer(0); + +or + + tie @array, 'Tie::File', $file, autodefer => 0; + + +Similarly, C<-Eautodefer(1)> re-enables autodeferment, and +C<-Eautodefer()> recovers the current value of the autodefer setting. + + +=head1 CONCURRENT ACCESS TO FILES + +Caching and deferred writing are inappropriate if you want the same +file to be accessed simultaneously from more than one process. You +will want to disable these features. You should do that by including +the C 0> option in your C calls; this will inhibit +caching and deferred writing. + +You will also want to lock the file while reading or writing it. You +can use the C<-Eflock> method for this. A future version of this +module may provide an 'autolocking' mode. + +=head1 CAVEATS + +(That's Latin for 'warnings'.) + +=over 4 + +=item * + +Reasonable effort was made to make this module efficient. Nevertheless, +changing the size of a record in the middle of a large file will +always be fairly slow, because everything after the new record must be +moved. + +=item * + +The behavior of tied arrays is not precisely the same as for regular +arrays. For example: + + # This DOES print "How unusual!" + undef $a[10]; print "How unusual!\n" if defined $a[10]; + +C-ing a C array element just blanks out the +corresponding record in the file. When you read it back again, you'll +get the empty string, so the supposedly-C'ed value will be +defined. Similarly, if you have C disabled, then + + # This DOES print "How unusual!" if 'autochomp' is disabled + undef $a[10]; + print "How unusual!\n" if $a[10]; + +Because when C is disabled, C<$a[10]> will read back as +C<"\n"> (or whatever the record separator string is.) + +There are other minor differences, particularly regarding C +and C, but in general, the correspondence is extremely close. + +=item * + +I have supposed that since this module is concerned with file I/O, +almost all normal use of it will be heavily I/O bound. This means +that the time to maintain complicated data structures inside the +module will be dominated by the time to actually perform the I/O. +When there was an opportunity to spend CPU time to avoid doing I/O, I +usually tried to take it. + +=item * + +You might be tempted to think that deferred writing is like +transactions, with C as C and C as +C, but it isn't, so don't. + +=item * + +There is a large memory overhead for each record offset and for each +cache entry: about 310 bytes per cached data record, and about 21 bytes per offset table entry. + +The per-record overhead will limit the maximum number of records you +can access per file. Note that I the length of the array +via C<$x = scalar @tied_file> accesses B records and stores their +offsets. The same for C, even if you exit the +loop early. + +=back + +=head1 SUBCLASSING + +This version promises absolutely nothing about the internals, which +may change without notice. A future version of the module will have a +well-defined and stable subclassing API. + +=head1 WHAT ABOUT C? + +People sometimes point out that L will do something similar, +and ask why C module is necessary. + +There are a number of reasons that you might prefer C. +A list is available at C. + +=head1 AUTHOR + +Mark Jason Dominus + +To contact the author, send email to: C + +To receive an announcement whenever a new version of this module is +released, send a blank email message to +C. + +The most recent version of this module, including documentation and +any news of importance, will be available at + + http://perl.plover.com/TieFile/ + + +=head1 LICENSE + +C version 0.96 is copyright (C) 2002 Mark Jason Dominus. + +This library is free software; you may redistribute it and/or modify +it under the same terms as Perl itself. + +These terms are your choice of any of (1) the Perl Artistic Licence, +or (2) version 2 of the GNU General Public License as published by the +Free Software Foundation, or (3) any later version of the GNU General +Public License. + +This library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with this library program; it should be in the file C. +If not, write to the Free Software Foundation, Inc., 59 Temple Place, +Suite 330, Boston, MA 02111 USA + +For licensing inquiries, contact the author at: + + Mark Jason Dominus + 255 S. Warnock St. + Philadelphia, PA 19107 + +=head1 WARRANTY + +C version 0.96 comes with ABSOLUTELY NO WARRANTY. +For details, see the license. + +=head1 THANKS + +Gigantic thanks to Jarkko Hietaniemi, for agreeing to put this in the +core when I hadn't written it yet, and for generally being helpful, +supportive, and competent. (Usually the rule is "choose any one.") +Also big thanks to Abhijit Menon-Sen for all of the same things. + +Special thanks to Craig Berry and Peter Prymmer (for VMS portability +help), Randy Kobes (for Win32 portability help), Clinton Pierce and +Autrijus Tang (for heroic eleventh-hour Win32 testing above and beyond +the call of duty), Michael G Schwern (for testing advice), and the +rest of the CPAN testers (for testing generally). + +Special thanks to Tels for suggesting several speed and memory +optimizations. + +Additional thanks to: +Edward Avis / +Mattia Barbon / +Tom Christiansen / +Gerrit Haase / +Gurusamy Sarathy / +Jarkko Hietaniemi (again) / +Nikola Knezevic / +John Kominetz / +Nick Ing-Simmons / +Tassilo von Parseval / +H. Dieter Pearcey / +Slaven Rezic / +Eric Roode / +Peter Scott / +Peter Somu / +Autrijus Tang (again) / +Tels (again) / +Juerd Waalboer + +=head1 TODO + +More tests. (Stuff I didn't think of yet.) + +Paragraph mode? + +Fixed-length mode. Leave-blanks mode. + +Maybe an autolocking mode? + +For many common uses of the module, the read cache is a liability. +For example, a program that inserts a single record, or that scans the +file once, will have a cache hit rate of zero. This suggests a major +optimization: The cache should be initially disabled. Here's a hybrid +approach: Initially, the cache is disabled, but the cache code +maintains statistics about how high the hit rate would be *if* it were +enabled. When it sees the hit rate get high enough, it enables +itself. The STAT comments in this code are the beginning of an +implementation of this. + +Record locking with fcntl()? Then the module might support an undo +log and get real transactions. What a tour de force that would be. + +Keeping track of the highest cached record. This would allow reads-in-a-row +to skip the cache lookup faster (if reading from 1..N with empty cache at +start, the last cached value will be always N-1). + +More tests. + +=cut + diff -ruN Tie-File-0.97/MANIFEST Tie-File-0.98/MANIFEST --- Tie-File-0.97/MANIFEST 2003-05-08 15:32:26.000000000 +0900 +++ Tie-File-0.98/MANIFEST 2006-12-22 22:49:56.000000000 +0900 @@ -39,6 +39,7 @@ t/40_abs_cache.t t/41_heap.t t/42_offset.t +t/43_memfile.t README WHATSNEW COPYING diff -ruN Tie-File-0.97/WHATSNEW Tie-File-0.98/WHATSNEW --- Tie-File-0.97/WHATSNEW 2003-05-28 00:59:21.000000000 +0900 +++ Tie-File-0.98/WHATSNEW 2006-12-22 23:26:20.000000000 +0900 @@ -1,3 +1,10 @@ +What's new in version 0.98: + + In-Memory storage support via PerlIO added. + +What's new in version 0.97: + + Perl-Core version as of Perl 5.8.8. What's new in version 0.96: diff -ruN Tie-File-0.97/lib/Tie/File.pm Tie-File-0.98/lib/Tie/File.pm --- Tie-File-0.97/lib/Tie/File.pm 2006-06-14 04:31:19.000000000 +0900 +++ Tie-File-0.98/lib/Tie/File.pm 2006-12-22 23:36:50.000000000 +0900 @@ -7,7 +7,7 @@ sub O_ACCMODE () { O_RDONLY | O_RDWR | O_WRONLY } -$VERSION = "0.97"; +$VERSION = "0.98"; my $DEFAULT_MEMORY_SIZE = 1<<21; # 2 megabytes my $DEFAULT_AUTODEFER_THRESHHOLD = 3; # 3 records my $DEFAULT_AUTODEFER_FILELEN_THRESHHOLD = 65536; # 16 disk blocksful @@ -104,7 +104,14 @@ require Symbol; $fh = Symbol::gensym(); } - sysopen $fh, $file, $opts{mode}, 0666 or return; + if (!defined($file) && $] >= 5.008 && PerlIO::Layer->find('perlio')) { + # Try in-memory file if perl supports perlio -- dankogai + my $memfile; + open $fh, '+>', \$memfile or return; + $opts{memfile} = \$memfile; + }else{ + sysopen $fh, $file, $opts{mode}, 0666 or return; + } binmode $fh; ++$opts{ourfh}; } @@ -912,7 +919,8 @@ sub _read_record { my $self = shift; my $rec; - { local $/ = $self->{recsep}; + { no warnings 'uninitialized'; # so in-memory is free from the warning. + local $/ = $self->{recsep}; my $fh = $self->{fh}; $rec = <$fh>; } @@ -2009,7 +2017,7 @@ =head1 SYNOPSIS - # This file documents Tie::File version 0.97 + # This file documents Tie::File version 0.98 use Tie::File; tie @array, 'Tie::File', filename or die ...; @@ -2051,6 +2059,23 @@ Lazy people and beginners may now stop reading the manual. +=head2 In-Memory File + +Perl 5.8 adds support to in-memory file and Tie::File 0.98 and higher +makes use of this feature. To use this feature, just pass to +the filename, just like DB_File and many other tie modules which +support both on-disk files and in-memory files, + +Though not time-efficient, you may save memory if the average size of +array element is 20 bytes or less. This case is typical when the +array contains only numbers. + +In practice, you should consider using L, L +and so forth instead of Tie::File since these are more optimezed for +in-memory storage. But for TMTOWTDI's sake and the tribute to Late +Nick Ing-Simmons who added PerlIO on which in-memmory file is +suppoted, I have added this feature (dankogai) + =head2 C What is a 'record'? By default, the meaning is the same as for the @@ -2532,7 +2557,7 @@ =head1 LICENSE -C version 0.97 is copyright (C) 2003 Mark Jason Dominus. +C version 0.98 is copyright (C) 2003 Mark Jason Dominus. This library is free software; you may redistribute it and/or modify it under the same terms as Perl itself. @@ -2560,7 +2585,7 @@ =head1 WARRANTY -C version 0.97 comes with ABSOLUTELY NO WARRANTY. +C version 0.98 comes with ABSOLUTELY NO WARRANTY. For details, see the license. =head1 THANKS diff -ruN Tie-File-0.97/t/00_version.t Tie-File-0.98/t/00_version.t --- Tie-File-0.97/t/00_version.t 2006-06-14 04:31:19.000000000 +0900 +++ Tie-File-0.98/t/00_version.t 2006-12-22 23:35:37.000000000 +0900 @@ -2,7 +2,7 @@ print "1..1\n"; -my $testversion = "0.97"; +my $testversion = "0.98"; use Tie::File; if ($Tie::File::VERSION != $testversion) { diff -ruN Tie-File-0.97/t/43_memfile.t Tie-File-0.98/t/43_memfile.t --- Tie-File-0.97/t/43_memfile.t 1970-01-01 09:00:00.000000000 +0900 +++ Tie-File-0.98/t/43_memfile.t 2006-12-22 22:57:50.000000000 +0900 @@ -0,0 +1,78 @@ +# +# $Id: 01-basic.t,v 0.1 2006/12/21 21:30:29 dankogai Exp $ +# +# Originally as Tie-Array-Pack/t/02-basic.t +# + +BEGIN { + if ($] < 5.008) { + print "1..0 # Skip: Perl 5.8 or better required\n"; + exit 0; + } + unless (PerlIO::Layer->find('perlio')){ + print "1..0 # Skip: PerlIO required\n"; + exit 0; + } +} +use strict; +use warnings; +no warnings 'uninitialized'; +use Test::More tests=>18; +use Tie::File; + +our $DEBUG = shift || 0; + +my @a; +tie my @t, 'Tie::File' => undef or die "$!"; +is ref(tied(@t)), 'Tie::File', "ref(tied(\@t)) eq Tie::File"; + +is_deeply \@a, \@t, "(@a)==(@t)"; + +@t = @a = ( 1 .. 4 ); +is_deeply \@a, \@t, "(@a)==(@t)"; + +$a[$_]-- for ( 0 .. @a - 1 ); +$t[$_]-- for ( 0 .. @t - 1 ); +is_deeply \@a, \@t, "-- => (@a)==(@t)"; + +push @a, ( 4 .. 7 ); +push @t, ( 4 .. 7 ); +is_deeply \@a, \@t, "pushed => (@a)==(@t)"; + +unshift @a, ( 8 .. 11 ); +unshift @t, ( 8 .. 11 ); +is_deeply \@a, \@t, "unshifted (@a)==(@t)"; + +my $a = pop @a; +my $t = pop @t; +is $a, $t, "pop => $a == $t"; +is_deeply \@a, \@t, "popped => (@a)==(@t)"; + +$a = shift @a; +$t = shift @t; +is $a, $t, "shift => $a == $t"; +is_deeply \@a, \@t, "shifted => (@a)==(@t)"; + +my @A = splice( @a, 1, 2, 3, 4 ); +my @T = splice( @t, 1, 2, 3, 4 ); +is_deeply \@A, \@T, "splice => (@A)==(@T)"; +is_deeply \@a, \@t, "spliced => (@a)==(@t)"; +@A = splice( @a, 1, 2, 3 ); +@T = splice( @t, 1, 2, 3 ); +is_deeply \@A, \@T, "splice => (@A)==(@T)"; +is_deeply \@a, \@t, "spliced => (@a)==(@t)"; +@A = splice( @a, 1, 2 ); +@T = splice( @t, 1, 2 ); +is_deeply \@A, \@T, "splice => (@A)==(@T)"; +is_deeply \@a, \@t, "spliced => (@a)==(@t)"; +@A = splice( @a, 1 ); +@T = splice( @t, 1 ); +is_deeply \@A, \@T, "splice => (@A)==(@T)"; +is_deeply \@a, \@t, "spliced => (@a)==(@t)"; + +if ($DEBUG){ + require Data::Dumper; + no warnings 'once'; + local $Data::Dumper::Useqq = 1; + warn Data::Dumper::Dumper(tied(@t)); +}