Move library code to lib/

Fixes accidental inclusion of test instrumentation into the all-in-one
script.

lib/Directory/Simplify/Instruction/CopyTimestamp.pm

@@ -0,0 +1,33 @@
+package Directory::Simplify::Instruction::CopyTimestamp;
+# vi: et sts=4 sw=4 ts=4
+use strict;
+use warnings;
+use overload '""' => 'as_string';
+
+# :squash-remove-start:
+require Directory::Simplify::Utils;
+# :squash-remove-end:
+
+sub new {
+    my $class = shift;
+    return bless {
+        @_,
+    }, $class;
+}
+
+sub run {
+    my $self = shift;
+    # preserve older time stamp
+    utime $self->{source}->{atime}, $self->{source}->{mtime}, $self->{target}->{name};
+}
+
+sub bytes_freed {
+    return 0;
+}
+
+sub as_string {
+    my $self = shift;
+    return sprintf 'touch -r %s %s', Directory::Simplify::Utils::shell_quote($self->{source}->{name}, $self->{target}->{name});
+}
+
+1;

lib/Directory/Simplify/Instruction/Generator.pm

@@ -0,0 +1,180 @@
+package Directory::Simplify::Instruction::Generator;
+# vi: et sts=4 sw=4 ts=4
+use strict;
+use warnings;
+use overload '""' => 'as_string';
+use File::Basename qw/ dirname /;
+use File::Compare qw/ compare /;
+
+# :squash-remove-start:
+require Directory::Simplify::Instruction::CopyTimestamp;
+require Directory::Simplify::Instruction::Hardlink;
+# :squash-remove-end:
+
+sub new {
+    my $class = shift;
+    return bless {
+        filehash => undef,
+        min_size => 1,
+        @_,
+    }, $class;
+}
+
+sub as_string {
+    my $self = shift;
+    join "\n", $self->instructions;
+}
+
+sub buckets {
+    my $self = shift;
+
+    my @candidate_lists = $self->{filehash}->entries;
+
+    my @buckets;
+    foreach my $candidates (@candidate_lists) {
+        my @ca = @{$candidates}; # make a clone
+        my @these_buckets;
+
+        # at least two files needed to link together
+        if (@ca > 1) {
+            ELIMINATOR: while (@ca) {
+                my $entry = shift @ca;
+
+                next ELIMINATOR if $self->_entry_should_be_skipped($entry);
+
+                foreach my $bucket_idx (0 .. $#these_buckets) {
+                    if (&_entries_are_hard_linkable($these_buckets[$bucket_idx]->[0], $entry)) {
+                        push @{$these_buckets[$bucket_idx]}, $entry;
+                        next ELIMINATOR;
+                    }
+                }
+                # didn't find a bucket (even though the hash matched!)
+                # -> new bucket
+                push @these_buckets, [$entry];
+            }
+        }
+        push @buckets, @these_buckets;
+    }
+
+    @buckets
+}
+
+sub _entry_should_be_skipped {
+    my ($self, $entry_a) = @_;
+    # too small to be hard-linked
+    if ($entry_a->{size} < $self->{min_size}) {
+        return 1;
+    }
+    return 0;
+}
+
+sub _entries_are_hard_linkable {
+    my ($entry_a, $entry_b) = @_;
+
+    # obviously, if the sizes aren't the same, they're not the same file
+    unless (&_entries_sizes_match($entry_a, $entry_b)) {
+        return 0;
+    }
+
+    # they're the same file, don't try it
+    if (&_entries_are_already_hard_linked($entry_a, $entry_b)) {
+        return 0;
+    }
+
+    if (&_entries_contents_match($entry_a, $entry_b)) {
+        return 1;
+    }
+    return 0;
+}
+
+sub oldest_mtime {
+    my $self = shift;
+    return sort {
+        $a->{mtime} <=> $b->{mtime}
+    } @_;
+}
+
+sub more_linked {
+    my $self = shift;
+    my %warned;
+    return sort {
+        if (! -w &dirname($a->{name})) {
+            warn "Warning: $a->{name} not able to be unlinked!" unless $warned{$a->{name}}++;
+            return 1; # favor a -> front
+        } elsif (! -w &dirname($b->{name})) {
+            warn "Warning: $b->{name} not able to be unlinked!" unless $warned{$b->{name}}++;
+            return -1; # favor b -> front
+        }
+        $b->{nlink} <=> $a->{nlink}
+    } @_;
+}
+
+sub _entries_are_already_hard_linked {
+    my ($entry_a, $entry_b) = @_;
+
+    if ($entry_a->{ino} == $entry_b->{ino} and
+        $entry_a->{dev} == $entry_b->{dev}) {
+        return 1;
+    }
+
+    return 0;
+}
+
+sub _entries_sizes_match {
+    my ($entry_a, $entry_b) = @_;
+    if ($entry_a->{size} != $entry_b->{size}) {
+        return 0;
+    }
+    return 1;
+}
+sub _entries_contents_match {
+    my ($entry_a, $entry_b) = @_;
+
+    my $contents_same = (0 == &File::Compare::compare($entry_a->{name}, $entry_b->{name}));
+
+    # warn about hash collision
+    unless ($contents_same) {
+        warn "Hash collision between files:\n* $entry_a->{name}\n* $entry_b->{name}\n  (don't panic)\n";
+    }
+    return $contents_same;
+}
+
+# generate hardlink instructions
+sub instructions {
+    require Scalar::Util;
+    my $self = shift;
+
+    # start generating instructions
+    my @inst;
+    foreach my $bucket ($self->buckets) {
+
+        # of the bucket, find the oldest timestamp
+        my ($oldest_entry) = $self->oldest_mtime(@{$bucket});
+
+        # of the bucket, find the file most embedded in the file system
+        my @to_link = $self->more_linked(@{$bucket});
+        my $most_linked_entry = shift @to_link;
+        foreach my $entry (@to_link) {
+            # XXX there shouldn't be a need to update entries' link counts,
+            # since this generates all the instructions at once
+            push @inst, Directory::Simplify::Instruction::Hardlink->new(
+                source => $most_linked_entry,
+                target => $entry,
+            );
+            push @inst, Directory::Simplify::Instruction::CopyTimestamp->new(
+                source => $oldest_entry,
+                target => $entry,
+            );
+        }
+        if (&Scalar::Util::refaddr($most_linked_entry) != &Scalar::Util::refaddr($oldest_entry)) {
+            # most_linked_entry should get its timestamp updated
+            push @inst, Directory::Simplify::Instruction::CopyTimestamp->new(
+                source => $oldest_entry,
+                target => $most_linked_entry,
+            );
+        }
+    }
+    @inst
+}
+
+1;

lib/Directory/Simplify/Instruction/Hardlink.pm

@@ -0,0 +1,46 @@
+package Directory::Simplify::Instruction::Hardlink;
+# vi: et sts=4 sw=4 ts=4
+use strict;
+use warnings;
+use overload '""' => 'as_string';
+
+# :squash-remove-start:
+require Directory::Simplify::Utils;
+# :squash-remove-end:
+
+sub new {
+    my $class = shift;
+    return bless {
+        freed => 0,
+        @_,
+    }, $class;
+}
+
+sub run {
+    my $self = shift;
+    # hard link the files
+
+    unless (unlink $self->{target}->{name}) {
+        die "Failed to remove file `$self->{target}->{name}': $!\n";
+    }
+    unless (link $self->{source}->{name}, $self->{target}->{name}) {
+        die "Failed to hard link `$self->{source}->{name}' => `$self->{target}->{name}': $!";
+    }
+    # bookkeeping
+    ++$self->{source}->{nlink};
+    if (--$self->{target}->{nlink} == 0) {
+        $self->{freed} = $self->{target}->{size};
+    }
+}
+
+sub bytes_freed {
+    my $self = shift;
+    return $self->{freed};
+}
+
+sub as_string {
+    my $self = shift;
+    return sprintf 'ln -sf %s %s', Directory::Simplify::Utils::shell_quote($self->{source}->{name}, $self->{target}->{name});
+}
+
+1;