Major updates to perl scripts

Add new git backend in VCS_git.pm

Switch from an old-style set of function calls to an OO API. This
allows for initialisation and some state to be kept in the VCS_git.pm
module - namely a per-file cache of commit hashes for a massive
performance boost when doing lots of lookups.

Extend the API with 2 new utility functions:
 * get_oldest_revision()
 * next_revision()

Extended the vcs_cmp_rev() function to take a filename too.

Add a test harness to validate the git and cvs backends.

Add switch_to_git_translations.pl to walk the tree and switch from cvs
revisions to git commit hashes in translation-check headers.

Change all of our local scripts to use the new Local::VCS frontend
*where it makes sense*. Some scripts will behave slightly differently,
as the new world can't exactly match the old behaviour.

CVS version numbers

check_desc_trans.pl: 1.9 -> 1.10 
check_trans.pl: 1.93 -> 1.94 
copypage.pl: 1.42 -> 1.43 
karma.pl: 1.6 -> 1.7 
remove_stale.pl: 1.22 -> 1.23 
smart_change.pl: 1.8 -> 1.9 
stattrans.pl: 1.127 -> 1.128 
switch_to_git_translations.pl: INITIAL -> 1.1 
touch_translations.pl: 1.9 -> 1.10 
vcs-test.pl: INITIAL -> 1.1 
Perl/Local/Util.pm: 1.4 -> 1.5 
Perl/Local/VCS.pm: 1.3 -> 1.4 
Perl/Local/VCS_CVS.pm: 1.13 -> 1.14 
Perl/Local/VCS_git.pm: 1.12 -> 1.13 
Perl/Webwml/Langs.pm: 1.5 -> 1.6 
Perl/Webwml/TransIgnore.pm: 1.3 -> 1.4

6 files changed, 729 insertions, 520 deletions

diff --git a/Perl/Local/Util.pm b/Perl/Local/Util.pm
index 8b11106e8d1..4277ef78964 100644
--- a/Perl/Local/Util.pm
+++ b/Perl/Local/Util.pm
@@ -29,8 +29,7 @@ use warnings;
 
 BEGIN {
 	use base qw( Exporter );
-
-	our $VERSION = sprintf "%s", q$Revision$ =~ /([0-9.]+)/;
+	our $VERSION = "1.2.3";
 	our @EXPORT_OK = qw( uniq read_file );
 	our %EXPORT_TAGS = ( 'all' => [@EXPORT_OK] );
 }
diff --git a/Perl/Local/VCS.pm b/Perl/Local/VCS.pm
index 59cd609bef1..802688525a4 100644
--- a/Perl/Local/VCS.pm
+++ b/Perl/Local/VCS.pm
@@ -39,4 +39,19 @@ sub import
 	}
 }
 
+sub new
+{
+	if ( -d 'CVS' )
+	{
+		require Local::VCS_CVS;
+		return Local::VCS_CVS->new(@_);
+	}
+	# fall back to git
+	else
+	{
+		require Local::VCS_git;
+		return Local::VCS_git->new(@_);
+	}
+}    
+
 42;
diff --git a/Perl/Local/VCS_CVS.pm b/Perl/Local/VCS_CVS.pm
index ef93c482947..890f544c3a6 100644
--- a/Perl/Local/VCS_CVS.pm
+++ b/Perl/Local/VCS_CVS.pm
@@ -15,7 +15,8 @@ Local::VCS_CVS - generic wrapper around version control systems -- CVS version
  use Local::VCS_CVS;
  use Data::Dumper;
 
- my %info = vcs_path_info( '.', recursive => 1, verbose => 1 );
+ my $VCS = Local::VCS->new();
+ my %info = $VCS->path_info( '.', recursive => 1, verbose => 1 );
  print Dumper($info{'foo.wml'});
 
  my %info2 = svn_file_info( 'foo.wml' );
@@ -52,18 +53,50 @@ use warnings;
 BEGIN {
 	use base qw( Exporter );
 
-	our $VERSION = sprintf "%s", q$Revision$ =~ /([0-9.]+)/;
+	our $VERSION = "1.14";
 	our @EXPORT_OK = qw( 
-	                     &vcs_cmp_rev     &vcs_count_changes
-	                     &vcs_get_topdir 
-	                     &vcs_path_info   &vcs_file_info
-	                     &vcs_get_log     &vcs_get_diff
-	                     &vcs_get_file
+			     &new
 	                   );
 	our %EXPORT_TAGS = ( 'all' => [@EXPORT_OK] );
 }
 
 
+=item new
+
+This is the constructor.
+
+   my $VCS = Local::VCS->new();
+
+=cut
+
+sub new {
+        my $proto = shift;
+        my $class = ref($proto) || $proto;
+        my $self  = {
+		CACHE    => {},
+        };
+        bless ($self, $class);
+        return $self;
+}
+
+sub cache_file {
+    my $self = shift;
+    my $file = shift;
+    
+    if ($self->{CACHE}{"$file"}) {
+	print "$file is already cached...\n";
+	return;
+    }
+    print "Adding $file to cache\n";
+    $self->{CACHE}{"$file"} = 1;
+    return;
+}
+
+sub cache_repo {
+    my $self = shift;    
+    # Does nothing here...
+}    
+
 # handling debugging
 my $DEBUG = 0;
 sub _debug
@@ -78,17 +111,19 @@ sub _debug
 sub _typeoffile;
 
 
-=item vcs_cmp_rev
+=item cmp_rev
 
-Compare two revision strings.
+Compare two revision strings for a given file
 
-Takes two revision strings as arguments, and 
-returns 1 if the first one is largest, 
--1 if the second one is largest, 
+Takes the file path and two revision strings as arguments, and 
+returns 1 if the first one is newer, 
+-1 if the second one is newer, 
 0 if they are equal
 =cut
-sub vcs_cmp_rev
+sub cmp_rev
 {
+	my $self = shift;
+	my $file = shift || ""; # unused here
 	my $a = shift || '0';
 	my $b = shift || '0';
 
@@ -117,7 +152,7 @@ sub vcs_cmp_rev
 	croak "Internal error: this should never be executed";
 }
 
-=item vcs_count_changes
+=item count_changes
 
 Return the number of changes to particular file between two revisions
 
@@ -131,8 +166,9 @@ Example use:
 
 =cut
 
-sub vcs_count_changes
+sub count_changes
 {
+	my $self = shift;
 	my $file = shift  or  return undef;
 	my $rev1 = shift || '1.1';
 	my $rev2 = shift || 'HEAD';
@@ -142,7 +178,7 @@ sub vcs_count_changes
 	# find the version number of HEAD, if it was specified
 	if ( $rev2 eq 'HEAD' )
 	{
-		my %info = vcs_file_info( $file );
+		my %info = $self->file_info( $file );
 		return -1  if  not %info;
 		$rev2 = $info{'cmt_rev'};
 	}
@@ -167,7 +203,7 @@ sub vcs_count_changes
 }
 
 
-=item vcs_path_info
+=item path_info
 
 Return CVS information and status about a tree of files.
 
@@ -190,7 +226,7 @@ Optional remaining arguments are a hash array with options:
 
 Example uses:
 
-   my %info1 = $vcs_path_info( 'src' );
+   my %info1 = $path_info( 'src' );
    my %info2 = $readinfo( 'src', recursive => 1 );
    my %info3 = $readinfo( 'src', recursive => 1, match_pat => '\.c$' );
 
@@ -198,8 +234,9 @@ Example uses:
 
 # todo: verbose
 
-sub vcs_path_info
+sub path_info
 {
+	my $self = shift;
 	my ($dir,%options) = @_;
 
 	croak("No file or directory specified") unless $dir;
@@ -245,7 +282,7 @@ sub vcs_path_info
 	return %data;
 }
 
-=item vcs_file_info
+=item file_info
 
 Return VCS information and status about a single file
 
@@ -260,12 +297,13 @@ the specified file:
 
 Example use:
 
-   my %info = $vcs_file_info( 'foo.wml' );
+   my %info = $file_info( 'foo.wml' );
 
 =cut
 
-sub vcs_file_info
+sub file_info
 {
+	my $self = shift;
 	my $file = shift or carp("No file specified");
 	my %options = @_;
 
@@ -274,7 +312,7 @@ sub vcs_file_info
 	my ($basename,$dirname) = fileparse( rel2abs $file );
 
 	# note: for some weird reason, the file is returned as '.'
-	my %info = vcs_path_info( $dirname, 'recursive' => 0 );
+	my %info = $self->path_info( $dirname, 'recursive' => 0 );
 
 	if ( not ( exists $info{$basename} and $info{$basename} ) )
 	{
@@ -285,7 +323,7 @@ sub vcs_file_info
 	return %{ $info{$basename} };
 }
 
-=item vcs_get_log
+=item get_log
 
 Return the log info about a specified file
 
@@ -295,12 +333,13 @@ of the log entries
 
 Example use:
 
-   my @log_entries = vcs_get_log( 'foo.wml' );
+   my @log_entries = get_log( 'foo.wml' );
 
 =cut
 
-sub vcs_get_log
+sub get_log
 {
+	my $self = shift;
 	my $file = shift  or  return;
 	my $rev1 = shift || '0';
 	my $rev2 = shift || '';
@@ -353,7 +392,7 @@ sub vcs_get_log
 	return reverse @logdata;
 }
 
-=item vcs_get_diff
+=item get_diff
 
 Returns a hash of (filename,diff) pairs containing the unified diff between two version of a (number of) files.
 
@@ -365,14 +404,15 @@ modified) version is diffed against the latest checked in version.
 
 Example use:
 
-   my %diffs = vcs_get_diff( 'foo.wml', '1.4', '1.17' );
-   my %diffs = vcs_get_diff( 'bla.wml', '1.8' );
-   my %diffs = vcs_get_diff( 'bas.wml' );
+   my %diffs = get_diff( 'foo.wml', '1.4', '1.17' );
+   my %diffs = get_diff( 'bla.wml', '1.8' );
+   my %diffs = get_diff( 'bas.wml' );
 
 =cut
 
-sub vcs_get_diff
+sub get_diff
 {
+	my $self = shift;
 	my $file = shift  or  return;
 	my $rev1 = shift;
 	my $rev2 = shift;
@@ -388,6 +428,7 @@ sub vcs_get_diff
 	# set the record separator for cvs diff output
 	local $/ = "\n" . ('=' x 67) . "\n";
 
+#	print "$command\n";
 	open( my $cvs, '-|', $command ) 
 		or croak("Couldn't run `$command': $!");
 
@@ -401,17 +442,17 @@ sub vcs_get_diff
 		$record =~ s{ $/ \n? \Z }{}msx;
 
 		# remove the "Index:" line from the end of the record
-		$record =~ s{ ^Index: [^\n]+ \n+ \Z }{}msx;
+#		$record =~ s{ ^Index: [^\n]+ \n+ \Z }{}msx;
 
-		# remove the first four lines
-		$record =~ s{ \A (?: .*? \n ){4} }{}msx;
+		# remove the first three lines
+		$record =~ s{ \A (?: .*? \n ){3} }{}msx;
 
-		# get the file name
-		if ( not $record =~ m{ \A --- \s+ ([^\t]+) \t }msx )
-		{
-			croak("Parse error in output of `$command'");
-		}
-		my $file = $1;
+#		# get the file name
+#		if ( not $record =~ m{ \A --- \s+ ([^\t]+) \t }msx )
+#		{
+#			croak("Parse error in output of `$command'");
+#		}
+#		my $file = $1;
 
 		$data{$file} = $record;
 	}
@@ -433,7 +474,7 @@ sub _get_repository
 	return $repo;
 }
 
-=item vcs_get_file
+=item get_file
 
 Return a particular revision of a file
 
@@ -445,12 +486,13 @@ and returns it (without writing anything in the current checked-out tree)
 
 Example use:
 
-   my $text = vcs_get_file( 'foo.c', '1.12' );
+   my $text = get_file( 'foo.c', '1.12' );
 
 =cut
 
-sub vcs_get_file
+sub get_file
 {
+	my $self = shift;
 	my $file = shift or croak("No file specified");
 	my $rev  = shift or croak("No revision specified");
 
@@ -478,7 +520,67 @@ sub vcs_get_file
 	return $text;
 }
 
-=item vcs_get_topdir
+=item get_oldest_revision
+
+Return the version of the oldest version of a file
+
+The first argument is a name of a file.
+
+This function finds the oldest revision of a file that is known in the
+repository and returns it.
+
+Example use:
+
+   my $rev = get_oldest_revision( 'foo.c');
+
+=cut
+
+sub get_oldest_revision
+{
+	my $self = shift;
+	my $file = shift or croak("No file specified");
+
+	croak( "No such file: $file" ) unless -f $file;
+
+	return '1.1'; # earliest possible revision of any file, easy!
+}
+
+=item next_revision
+
+Given a file path and a current revision of that file, move backwards
+or forwards through the commit history and return a related revision.
+
+Takes three arguments: the file path, the start revision and an
+integer to specify which direction to move *and* how far. A negative
+number specifies backwards in history, a positive number specifies
+forwards.
+
+Example use:
+
+   my $rev = next_revision( 'foo.c', '72f6700577c79e6d284fbeac44366f6aa357d56d', -1);
+
+Returns the requested revision if it exists, otherwise *undef*
+
+=cut
+sub next_revision
+{
+	# For the file we're looking at, we can easily generate an
+	# array (list) of all the commit hashes. Then we can see where
+	# in that list the specified revision lies.
+	#
+	# FIXME: Only deals with simple moves backwards/forwards along the trunk
+
+	my $self = shift;
+	my $file = shift or return undef;
+	my $rev1 = shift or return undef;
+	my $move = shift or return undef;
+
+	my $newrev = $rev1;
+	$newrev =~ s/(\d+)$/($1 + $move)/e;
+	return $newrev;
+}
+
+=item get_topdir
 
 Return the top dir of the webwml repository
 
@@ -487,12 +589,13 @@ If it is not specified, by default the current directory is used.
 
 Example use:
 
-   my $dir = vcs_get_topdir( 'foo.c' );
+   my $dir = get_topdir( 'foo.c' );
 
 =cut
 
-sub vcs_get_topdir
+sub get_topdir
 {
+	my $self = shift;
 	my $file = shift || '.';
 
 	my $cvs = Local::Cvsinfo->new();
@@ -552,247 +655,3 @@ Free Software Foundation.
 # ignore for now, I will get rid of it as the rewrite progresses
 # -- Bas.
 __END__
-
-
-
-=item svn_diff
-
-Return diff for the specified file 
-
-The first argument is a name of a file.
-The second argument is the revision against which to take the diff (use undef for HEAD)
-If a thrird argument is present, it signifies that hte use want a diff between
-the version specified in the second agument and the one in the third argument
-
-Example use:
-
-   # get diff of local changes against head
-   my $diff1 = $svn_diff( 'foo.c' );
-   # get diff of local changes against revision 12
-   my $diff2 = $svn_diff( 'foo.c', 'r12' );
-   # get diff between version 11 and 12 of the file
-   my $diff1 = $svn_diff( 'foo.c', 'r11', 'r12' );
-
-=cut
-
-sub svn_diff
-{
-	my $file = shift or carp("No file specified");
-	my $rev1 = shift or carp("No orig revision specified");
-	my $rev2 = shift or carp("No target revision specified");
-
-	carp( "No such file: $file" ) unless -e $file;
-
-	# intitalize SVN client
-	my $ctx = SVN::Client->new();
-
-	# create twoo filehandles for output and error streams
-
-	# TODO: this doesn't work (bug in SVN::Client?)
-	my ($out,$err);
-	#open ( my $fd_out, '>', \$out ) or croak("Couldn't open \\\$out");
-	#open ( my $fd_err, '>', \$err ) or croak("Couldn't open \\\$err");
-
-	open ( my $fd_out, '+>', undef ) or croak("Couldn't open anonymous output");
-	open ( my $fd_err, '+>', undef ) or croak("Couldn't open anonymous error");
-
-	$ctx->diff( 
-		[],  # options to diff (-u is default)
-		$file, $rev1, # first file
-		$file, $rev2, # second file
-		1, # recursiveness
-		1, # don't bother with ancestors
-		0, # do diff deleted files
-		$fd_out, # output file
-		$fd_err, # error output file
-	);
-
-	# read the stuff from the files
-	seek( $fd_out, 0, SEEK_SET );
-	seek( $fd_err, 0, SEEK_SET );
-	{ 
-		local $/;
-		$out = <$fd_out>;
-		$err = <$fd_err>;
-	}
-
-	# done with the files
-	close( $fd_out );
-	close( $fd_err );
-
-	# croak on error
-	croak( $err ) if $err;
-
-	# return the diff
-	return $out;
-}
-
-
-=item svn_log
-
-Return the log entries of a particular file
-
-The first argument is a name of a file.
-The (optional) second  and third argument specify the revision range
-
-This function retrieves the log entry/entries of the specified revision(s) for
-the specified file.  If only a file name is given, the entire history is
-returned; if only 1 revision is specified, the log entrie of that particular
-revision is returned; if two revisions are specified, all log entries in
-between are returned.
-
-Example use:
-
-   my @log = svn_log( 'foo.c' );
-   my @log = svn_log( 'foo.c', 'r42' );
-   my @log = svn_log( 'foo.c', 'r42', 'r112' );
-   my @log = svn_log( 'foo.c', 'r42', 'HEAD' );
-
-=cut
-
-my @_log_collection;
-
-sub _log_receiver
-{
-	my $paths  = shift; # NOTE: not used
-	my $rev    = shift;
-	my $author = shift;
-	my $date   = str2time( shift );
-	my $msg    = shift;
-
-	push @_log_collection, { 
-		'rev'     => $rev,
-		'author'  => $author,
-		'date'    => $date,
-		'message' => $msg,
-	};
-
-}
-
-sub svn_log
-{
-	my $file = shift or carp("No file specified");
-	my $rev1 = shift || '0';
-	my $rev2 = shift || 'HEAD';
-
-	carp( "No such file: $file" ) unless -e $file;
-
-	# clear log
-	@_log_collection = ();
-
-	# intitialize SVN client
-	my $ctx = SVN::Client->new();
-
-	eval {
-		$ctx->log( 
-			$file,
-			$rev1,
-			$rev2,
-			0,  # determine which files were changed on each revision?
-			0,  # don't traverse history of copies?
-			\&_log_receiver
-		);
-	};
-	carp($@) if $@;
-
-
-	# return a copy of the logs
-	return @_log_collection;
-}
-
-=item svn_get_info
-
-Return info about the (local) Subversion repository
-
-The first argument is a name of a checked-out file or directory.
-
-Example use:
-
-   my %info = svn_info( 'foo.c' );
-
-=cut
-
-my %_info_data;
-
-sub _info_receiver
-{
-	my( $path, $info, $pool ) = @_;
-
-	# return if the info is already known
-	return if %_info_data;
-
-	%_info_data = (
-		'url'                 => $info->URL(),
-		'rev'                 => $info->rev(),
-		'kind'                => $info->kind(),
-		'root'                => $info->repos_root_URL(),
-		'uuid'                => $info->repos_UUID(),
-		'last_changed_rev'    => $info->last_changed_rev(),
-		'last_changed_date'   => $info->last_changed_date(),
-		'last_changed_author' => $info->last_changed_author(),
-	);
-};
-
-sub svn_get_info
-{
-	my $file = shift or carp("No file specified");
-
-	$file = rel2abs( $file );
-
-	# intitialize SVN client
-	my $ctx = SVN::Client->new();
-
-	# reset the info hash
-	%_info_data = ();
-
-	eval {
-		$ctx->info( 
-			$file,
-			undef, # no revision info, so...
-			undef, # ...only use local info
-			\&_info_receiver,
-			0,     # no, don't recurse
-		);
-	};
-	carp($@) if $@;
-
-	return %_info_data;
-}
-
-
-=item svn_get_depth
-
-Find how deep we are inside the repository
-
-The first argument is a name of a checked-out file or directory.
-
-Example use:
-
-   my $depth = svn_get_topdir( 'foo.c' );
-
-=cut
-
-sub svn_get_depth
-{
-	my $file = shift or carp("No file specified");
-
-
-	my %info = svn_get_info( $file );
-	my $top  = $info{'url'};
-	my $root = $info{'root'};
-
-	# if $file really is a file (not a dir), only look at the directory part of
-	# the filename
-	$top = dirname( $top )  if $info{'kind'} == 1;
-
-	# remove the root from the start of url to get a top dir
-	$top =~ s{^\Q$root\E}{};
-	$top =~ s{/+}{/};
-
-	# count the number of elements in the path
-	my $num = scalar splitdir( $top );
-
-	# minus 1, because $top starts with a '/', and thus splitdir adds an empty
-	# field at the beginning
-	return $num - 1;
-}
diff --git a/Perl/Local/VCS_git.pm b/Perl/Local/VCS_git.pm
index cfa5affef03..410bf81c785 100644
--- a/Perl/Local/VCS_git.pm
+++ b/Perl/Local/VCS_git.pm
@@ -1,10 +1,10 @@
 #!/usr/bin/perl
 
-##  Copyright (C) 2008  Bas Zoetekouw <bas@debian.org>
+## Copyright (C) 2018  Steve McIntyre <93sam@debian.org>
 ##
-##  This program is free software; you can redistribute it and/or modify it
-##  under the terms of version 2 of the GNU General Public License as published
-##  by the Free Software Foundation.
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of version 2 of the GNU General Public License as published
+## by the Free Software Foundation.
 
 =head1 NAME
 
@@ -15,7 +15,8 @@ Local::VCS_git - generic wrapper around version control systems -- git version
  use Local::VCS_git;
  use Data::Dumper;
 
- my %info = vcs_path_info( '.', recursive => 1, verbose => 1 );
+ my $VCS = Local::VCS->new();
+ my %info = $VCS->path_info( '.', recursive => 1, verbose => 1 );
  print Dumper($info{'foo.wml'});
 
 =head1 DESCRIPTION
@@ -33,8 +34,8 @@ package Local::VCS_git;
 
 use 5.008;
 
-use Local::Gitinfo;
 use File::Basename;
+use File::Find;
 use File::Spec::Functions qw( rel2abs splitdir catfile rootdir catdir );
 use File::stat;
 use Carp;
@@ -42,6 +43,10 @@ use Fcntl qw/ SEEK_SET /;
 use Data::Dumper;
 use Date::Parse;
 use POSIX qw/ WIFEXITED /;
+use List::MoreUtils 'first_index'; 
+use Cwd qw(cwd);
+use Time::HiRes qw/gettimeofday/;
+use Data::Dumper;
 
 use strict;
 use warnings;
@@ -49,75 +54,226 @@ use warnings;
 BEGIN {
 	use base qw( Exporter );
 
-	our $VERSION = sprintf "%s", q$Revision$ =~ /([0-9.]+)/;
+	our $VERSION = "1.13";
 	our @EXPORT_OK = qw( 
-	                     &vcs_cmp_rev     &vcs_count_changes
-	                     &vcs_get_topdir 
-	                     &vcs_path_info   &vcs_file_info
-	                     &vcs_get_log     &vcs_get_diff
-	                     &vcs_get_file
+			     &new
 	                   );
 	our %EXPORT_TAGS = ( 'all' => [@EXPORT_OK] );
 }
 
+=item new
+
+This is the constructor.
+
+   my $VCS = Local::VCS->new();
+
+=cut
+
+sub new {
+        my $proto = shift;
+        my $class = ref($proto) || $proto;
+        my $self  = {
+		CACHE    => {},
+		REPO_CACHED => 0,
+        };
+        bless ($self, $class);
+        return $self;
+}
 
 # handling debugging
 my $DEBUG = 0;
+
+sub _get_time()
+{
+    my @tm;
+    my $text;
+    my ($seconds, $microseconds) = gettimeofday;
+
+    @tm = gmtime();
+    $text = sprintf("%4d-%02d-%02d %02d:%02d:%02d.%6d UTC",
+                    (1900 + $tm[5]),(1 + $tm[4]),$tm[3],$tm[2],$tm[1],$tm[0], $microseconds);
+    return $text;
+}
+
 sub _debug
 {
 	my @text = @_;
 	return unless $DEBUG;
-	print STDERR "=> ", @text, "\n";
+	my $timestamp = _get_time();
+	print STDERR "=> ", $timestamp, " ", @text, "\n";
+	return;
+}
+
+sub _add_cache_entry {
+    my $self = shift;
+    my $file = shift;
+    my %entry;
+    $entry{'cmt_date'} = shift;
+    $entry{'cmt_rev'} = shift;
+    my $tmp;
+    my @list;
+    if ($self->{CACHE}{"$file"}) {
+	$tmp = $self->{CACHE}{"$file"};
+	@list = @$tmp;
+    }
+    push(@list, \%entry);
+    $self->{CACHE}{"$file"} = \@list;
+}
+
+sub cache_file {
+    my $self = shift;
+    my $file = shift;
+    
+    _debug "cache_file($file)";
+    if ($self->{CACHE}{"$file"}) {
+#	print "$file is already cached...\n";
+	_debug "cache_file($file) returning early";
 	return;
+    }
+#    print "Adding $file to cache\n";
+    my (@commits);
+    open (GITLOG, "git log -p -m --first-parent --name-only --numstat --format=format:\"%H %ct\" -- $file |") or die "Can't fork git log: $!\n";
+    my ($cmt_date, $cmt_rev);
+    while (my $line = <GITLOG>) {
+	chomp $line;
+	if ($line =~ m/^([[:xdigit:]]+) (\d+)$/) {
+	    $cmt_rev = $1;
+	    $cmt_date = $2;
+	    next;
+	} elsif ($line =~ m{^$file$}) {
+	    $self->_add_cache_entry($file, $cmt_date, $cmt_rev);
+	}
+    }
+    close GITLOG;
+    _debug "cache_file($file) done";
+    return;
 }
 
-# return the type of the specified file
-sub _typeoffile;
+sub cache_repo {
+    my $self = shift;    
 
+    _debug "cache_repo()";
+    # If we've already read the commit history into our cache, return
+    # immediately
+    if ($self->{REPO_CACHED}) {
+	_debug "cache_repo() returning early";
+	return;
+    }
+
+    # If not, clear the cache and rebuild from scratch. We might havs
+    # some files cached individually, and that would confuse things
+    # now.
+    $self->{CACHE} = {};
+
+    # Store the current directory so we can return there
+    my $start_dir = cwd;
+    my $topdir = $self->get_topdir();
+    chdir ($topdir) or die "Can't chdir to $topdir: $!\n";    
+
+    my (@commits);
+    my $count = 0;
+    open (GITLOG, "git log -p -m --first-parent --name-only --numstat --format=format:\"%H %ct\" |") or die "Can't fork git log: $!\n";
+    my ($cmt_date, $cmt_rev);
+    while (my $line = <GITLOG>) {
+	chomp $line;
+	if ($line =~ m/^([[:xdigit:]]+) (\d+)$/) {
+	    $cmt_rev = $1;
+	    $cmt_date = $2;
+	    next;
+	} elsif ($line =~ m{^(\S+)$}) {
+	    my $file = $1;
+	    $self->_add_cache_entry($file, $cmt_date, $cmt_rev);
+	    $count++;
+	}
+    }
+    close GITLOG;
+    chdir ($start_dir);
+    $self->{REPO_CACHED} = 1;    
+#    print Dumper($self->{CACHE});
+    my $tmp = $self->{CACHE};
+    my $num_files = scalar(keys %$tmp);
+    _debug "cache_repo() done, $count file commits, $num_files files";
+}    
+
+# Internal helper function - grab a list of all the commits to a given
+# file
+sub _grab_commits
+{    
+    my $self = shift;
+    my $file = shift or return undef;
+    $self->cache_file($file);
+    my $tmp = $self->{CACHE}{"$file"};
+    if (defined $tmp) {
+	my @commits = @$tmp;
+#    print Dumper(@commits);
+	return @commits;
+    }
+    return undef;
+}
 
-=item vcs_cmp_rev
+=item cmp_rev
 
-Compare two revision strings.
+Compare two revision strings for a given file.
 
-Takes two revision strings as arguments, and 
-returns 1 if the first one is largest, 
--1 if the second one is largest, 
+Takes the file path and two revision strings as arguments, and 
+returns 1 if the first one is newer, 
+-1 if the second one is newer, 
 0 if they are equal
 
-FIXME: this needs to be "translated" into git and hashes
-
 =cut
-sub vcs_cmp_rev
+sub cmp_rev
 {
-	my $a = shift || '0';
-	my $b = shift || '0';
-
-	my @a = split( /\./, $a );
-	my @b = split( /\./, $b );
-
-	# compare the two revision string term by term
-	my $i = 0;
-	while (1)
-	{
-		# first check if there are terms left in both revisions
-		if ( $i > $#a and $i>$#b ) { return 0 };
-		if ( $i > $#a ) { return -1 };
-		if ( $i > $#b ) { return  1 };
-
-		# then check this term
-		if ( $a[$i] < $b[$i] ) { return -1; }
-		if ( $a[$i] > $b[$i] ) { return  1; }
-
-		# terms are equal, look at the next one
-
-		$i++;
+	# For the file we're looking at, we can easily generate an
+	# array (list) of all the commit hashes. Then we can see where
+	# in that list the specified revisions lie (from newest to
+	# oldest) - that's what we're going to compare.
+
+	my $self = shift;
+	my $file = shift or return undef;
+	my $rev1 = shift or return undef;
+	my $rev2 = shift or return undef;
+
+	my @commits = $self->_grab_commits($file);
+#	print Dumper(@commits);
+	my $pos1 = -1;
+	my $pos2 = -1;
+	my $count = 0;
+	foreach my $tmp(@commits) {
+	    my %entry = %$tmp;
+	    if ($entry{'cmt_rev'} =~ /\Q$rev1\E/) {
+		$pos1 = $count;
+	    }
+	    if ($entry{'cmt_rev'} =~ /\Q$rev2\E/) {
+		$pos2 = $count;
+	    }
+	    if ($pos1 != -1 and $pos2 != -1) {
+		last;
+	    }
+	    $count++;
+	}
+	if ($pos1 == -1) {
+	    # Not found
+	    print "ERROR: commit $rev1 not found in revisions of $file\n";
+	    return undef;
+	}
+	if ($pos2 == -1) {
+	    # Not found
+	    print "ERROR: commit $rev2 not found in revisions of $file\n";
+	    return undef;
+	}
+	if ($pos1 == $pos2) {
+	    return 0;
+	} elsif ($pos1 < $pos2) {
+	    return 1;
+	} else {
+	    return -1;
 	}
 
 	# should never be reached
 	croak "Internal error: this should never be executed";
 }
 
-=item vcs_count_changes
+=item count_changes
 
 Return the number of changes to particular file between two revisions
 
@@ -126,48 +282,83 @@ The second and third argument specify the revision range
 
 Example use:
 
-   my $num1 = vcs_count_changes( 'foo.c', 'r42', 'r70' );
-   my $num2 = vcs_count_changes( 'foo.c', 'r42', 'HEAD' );
+   my $num1 = count_changes( 'foo.c', 'r42', 'r70' );
+   my $num2 = count_changes( 'foo.c', 'r42', 'HEAD' );
    
-FIXME: converted into git and hashes, needs review and test
-
 =cut
 
-sub vcs_count_changes
+sub count_changes
 {
 	# FIXME: not sure if we need to handle the issue of wrong $rev1/$rev2 here
 	#        or the caller function will care.
 	#        Not sure if this function makes sense in a git context, either,
-    #        but just in case
+	#        but just in case
     
+	my $self = shift;
 	my $file = shift  or  return undef;
 	my $rev1 = shift || '';
-	my $rev2 = shift || 'HEAD';
+	my $rev2 = shift || '';
 
-	$rev1 = ''  if $rev1 eq 'n/a';
+	if ($rev1 =~ m/^\Q$rev2\E$/) { # same revisions
+	    return 0;
+	}
 
-	# for git, this is pretty easy: we simply compare the two version numbers
-	# note: we don't support branches (aren't used in the webwml repo anyway)
+	my @commits = $self->_grab_commits($file);
 
-	my $command = sprintf( 'git rev-list --count %s..%s %s', $rev1, $rev2, $file );
-	
-	open ( my $git, '-|', $command ) 
-		or croak("Error while executing `$command': $!");
-    my $text;
-	while ( my $line = <$git> )
-	{
-		$text .= $line;
+	# If unset, go for the last revision
+	if (length($rev2) == 0) {
+	    $rev2 = $commits[$#commits];
 	}
-	close( $git );
-	croak("Error while executing `$command': $!") unless WIFEXITED($?);
 
-	# return the number of changes (or error text)
-
-	return $text;
+	my $pos1 = -1;
+	my $pos2 = -1;
+	my $count = 0;
+	foreach my $tmp(@commits) {
+	    my %entry = %$tmp;
+	    if ($entry{'cmt_rev'} =~ /\Q$rev1\E/) {
+		$pos1 = $count;
+	    }
+	    if ($entry{'cmt_rev'} =~ /\Q$rev2\E/) {
+		$pos2 = $count;
+	    }
+	    if ($pos1 != -1 and $pos2 != -1) {
+		last;
+	    }
+	    $count++;
+	}
+	if ($pos1 == -1) {
+	    # Not found
+	    print "ERROR: commit $rev1 not found in revisions of $file\n";
+	    return undef;
+	}
+	if ($pos2 == -1) {
+	    # Not found
+	    print "ERROR: commit $rev2 not found in revisions of $file\n";
+	    return undef;
+	}
+	return $pos2 - $pos1;
 }
 
+# return the type of the input argument (file, dir, symlink, etc)
+sub _typeoffile
+{
+	my $file = shift  or  return;
 
-=item vcs_path_info
+	stat $file  or  return 'f'; # File is not here now; assume it
+				    # was a file!
+
+	return 'f'  if ( -f _ );
+	return 'd'  if ( -d _ );
+	return 'l'  if ( -l _ );
+	return 'S'  if ( -S _ );
+	return 'p'  if ( -p _ );
+	return 'b'  if ( -b _ );
+	return 'c'  if ( -c _ );
+
+	return '';
+}
+
+=item path_info
 
 Return git information and status about a tree of files.
 
@@ -190,20 +381,41 @@ Optional remaining arguments are a hash array with options:
 
 Example uses:
 
-   my %info1 = $vcs_path_info( 'src' );
-   my %info2 = $readinfo( 'src', recursive => 1 );
-   my %info3 = $readinfo( 'src', recursive => 1, match_pat => '\.c$' );
+   my %info1 = $VCS->path_info( 'src' );
+   my %info2 = $VCS->path_info( 'src', recursive => 1 );
+   my %info3 = $VCS->path_info( 'src', recursive => 1, match_pat => '\.c$' );
 
 =cut
 
 # todo: verbose
 
-sub vcs_path_info
+sub path_info
 {
+	# Two parts:
+	#
+	# (1)  Build a hash of all the files we want to know about
+	#
+	# (2a) Ask git about all the files it has, and pull out
+	#      information for ones in the hash from (1)
+	#
+	# OR
+	# 
+	# (2b) Grab that information from our cache of all the commit data,
+	#      if we have already been told to generate that cache.
+	#      *Don't* generate that cache automatically - for just a few
+	#      files it's quicker to just look up the data directly. If the
+	#      user is going to do a lot of lookups, let them populate the
+	#      cache up-front themselves if performance matters.
+	#
+	# This may not sound very quick, but it's much better than asking git
+	# about all the details individually!
+
+	my $self = shift;
 	my ($dir,%options) = @_;
+	my %files_wanted;
 
 	croak("No file or directory specified") unless $dir;
-	_debug "Called with $dir";
+	_debug "path_info ($dir)";
 
 	my $recurse   = $options{recursive} || $options{recurse} || 0;
 	my $match_pat = $options{match_pat} || undef;
@@ -213,39 +425,74 @@ sub vcs_path_info
 	_debug "Match pattern is '$match_pat'" if defined $match_pat;
 	_debug "Skip pattern is  '$skip_pat'"  if defined $skip_pat;
 
-	# $git->readinfo expects a matchfile input;  if nothing is specified, we
-	# pass a pattern that matches everything
-	$match_pat ||= '.'; 
-
-	$dir = rel2abs( $dir );
-
-	# use Local::Gitinfo to do the actual work in git
-	my $git = Local::Gitinfo->new();
-	$git->readinfo( $dir, recursive => $recurse, matchfile => [$match_pat] );
-	my $files = $git->files;
-
-	# construct a nice hash from the data we received from Gitinfo
-	my %data;
-	for my $file (keys %{$git->{FILES}})
-	{
-		# we return relative paths, so strip off the dir name
-		my $file_rel = $file;
-		$file_rel =~ s{^$dir/?}{};
-
-		# skip files that match the skip pattern
-		next if  $skip_pat  and  $file_rel =~ m{$skip_pat};
-
-		$data{$file_rel} = {
-			'cmt_rev'  => $git->{FILES}->{$file}->{'REV'},
-			'cmt_date' => str2time( $git->{FILES}->{$file}->{'DATE'} ),
-			'type'     => _typeoffile $file,
-		};
+	if ($recurse) {
+	    find( sub { $files_wanted{$File::Find::name} = 1 if -f and
+			    (!defined $match_pat or m/$match_pat/) and
+			    (!defined $skip_pat or not ($File::Find::name =~ m/$skip_pat/))}, $dir );
+	} else {
+	    find( sub { $files_wanted{$File::Find::name} = 1 if -f and
+			    ($File::Find::dir eq $dir) and
+			    (!defined $match_pat or m/$match_pat/) and
+			    (!defined $skip_pat or not ($File::Find::name =~ m/$skip_pat/))}, $dir );
 	}
 
-	return %data;
+	# Calling "git log" for each file individually is hatefully
+	# slow. Better option: call it once with appropriate options
+	# for the directory we're targeting, and parse the
+	# output. Gross, but it works.
+
+	my %pathinfo;
+
+	# Do we have the repo commit history cached?
+	if ($self->{REPO_CACHED}) {
+		# We do, use it! (2b above)
+		foreach my $file (keys %files_wanted) {
+		    my @commits = $self->_grab_commits($file);
+		    if (@commits) {
+			my $outfile = $file;
+			$outfile =~ s,^$dir/,,;
+			# Grab the data we want from the first entry in the
+			# commits list, i.e. the most recent commit.
+			$pathinfo{$outfile}{'type'} = _typeoffile("$file");
+			$pathinfo{$outfile}{'cmt_date'} = $commits[0]{'cmt_date'};
+			$pathinfo{$outfile}{'cmt_rev'} = $commits[0]{'cmt_rev'};
+		    } else {
+			_debug "Ignoring file $file";
+		    }
+		}
+	} else {
+	    # We don't, so we need to talk to git. (2a above)
+	    open (GITLOG, "git log -p -m --first-parent --name-only --numstat --format=format:\"%H %ct\" $dir|")
+		or die "Failed to fork git log: $!\n";
+	    my $cmt_date;
+	    my $cmt_rev;
+	    my $file;
+	    while (my $line = <GITLOG>) {
+		chomp $line;
+		if ($line =~ m/^([[:xdigit:]]+) (\d+)$/) {
+		    $cmt_rev = $1;
+		    $cmt_date = $2;
+		    next;
+		} elsif ($line =~ m{^$dir/(\S+)$}) {
+		    $file = $1;
+		    # Only store information if:
+		    # We want this file, and
+		    # We don't have data for it yet (i.e. only show
+		    # the most recent version of a file)
+		    if ($files_wanted{"$dir/$file"} and not defined $pathinfo{$file}) {
+			$pathinfo{$file}{'type'} = _typeoffile("$dir/$file");
+			$pathinfo{$file}{'cmt_date'} = $cmt_date;
+			$pathinfo{$file}{'cmt_rev'} = $cmt_rev;
+		    }
+		}   
+	    }
+	    close GITLOG;
+	}
+	_debug "path_info ($dir) returning";
+	return %pathinfo;	
 }
 
-=item vcs_file_info
+=item file_info
 
 Return VCS information and status about a single file
 
@@ -260,32 +507,30 @@ the specified file:
 
 Example use:
 
-   my %info = $vcs_file_info( 'foo.wml' );
+   my %info = $VCS->file_info( 'foo.wml' );
 
 =cut
 
-sub vcs_file_info
+sub file_info
 {
+	my $self = shift;
 	my $file = shift or carp("No file specified");
 	my %options = @_;
-
 	my $quiet = $options{quiet} || undef;
-
-	my ($basename,$dirname) = fileparse( rel2abs $file );
-
-	# note: for some weird reason, the file is returned as '.'
-	my %info = vcs_path_info( $dirname, 'recursive' => 0 );
-
-	if ( not ( exists $info{$basename} and $info{$basename} ) )
-	{
-		carp("No info found about `$file' (does the file exist?)") if ( ! $quiet );
-		return;
+	my %pathinfo;
+	my @commits = $self->_grab_commits($file);
+	if (@commits) {
+	    # Grab the data we want from the first entry in the
+	    # commits list, i.e. the most recent commit.
+	    $pathinfo{'type'} = _typeoffile("$file");
+	    $pathinfo{'cmt_date'} = $commits[0]{'cmt_date'};
+	    $pathinfo{'cmt_rev'} = $commits[0]{'cmt_rev'};
 	}
 
-	return %{ $info{$basename} };
+	return %pathinfo;	
 }
 
-=item vcs_get_log
+=item get_log
 
 Return the log info about a specified file
 
@@ -295,66 +540,91 @@ of the log entries
 
 Example use:
 
-   my @log_entries = vcs_get_log( 'foo.wml' );
+   my @log_entries = get_log( 'foo.wml' );
    
-FIXME: converted into git and hashes, needs review and test
-
 =cut
 
-sub vcs_get_log
+sub get_log
 {
+	my $self = shift;
 	my $file = shift  or  return;
 	my $rev1 = shift || '';
 	my $rev2 = shift || '';
-
 	my @logdata;
+	my $command;	
+	if ($rev1 eq '' and $rev2 eq '') {
+	    $command = sprintf( 'git log --date=unix %s', $file );
+	} elsif ($rev2 eq '') {
+	    $command = sprintf( 'git log --date=unix %s^..%s %s', $rev1, $rev1, $file );
+	} elsif ($rev1 eq '') {
+	    $command = sprintf( 'git log --date=unix ..%s %s', $rev2, $file );
+	} else {
+	    $command = sprintf( 'git log --date=unix %s..%s %s', $rev1, $rev2, $file );
+	}		
+
+	_debug "get_log: running $command";
 
-	# set the record separator for git log output
-	local $/ = "\n----------------------------\n";
-
-	my $command = sprintf( 'git log %s..%s %s', $rev1, $rev2, $file );
 	open( my $git, '-|', $command ) 
 		or croak("Couldn't run `$command': $!");
 
-	# read the consequetive records
-	while ( my $record = <$git> )
+	my $revision;
+	my $author;
+	my $date;
+	my $message;
+	my $first_record_done = 0;
+
+	# read and parse the log records
+	while ( my $line = <$git> )
 	{
-		#print "==> $record\n";
-
-		# the first 3 lines of a record contain metadata that looks like this:
-		# commit abcdefg435768938de
-        # Author: Jane Doe <email@example.com>
-        # Date:   Tue Nov 7 11:47:24 2017 +0100
-		
-		# first split off the record
-		my ($metadata1,$metadata2,$metadata3,$logmessage) = split( /\n/, $record, 4 );
-
-		my ($revision)     = $metadata1 =~ m{^commit (.+)};
-		my ($author)       = $metadata2 =~ m{^Author: (.+)};
-		my ($date)         = $metadata3 =~ m{^Date: (.+)};
-		
-		croak( "Couldn't parse output of `$command'" ) 
-			unless  $revision and $date and $author;
-
-		# convert date to unixtime
-		$date = str2time( $date );
-
-		# last line of the log message is still the record separator
-		$logmessage =~ s{\n[^\n]+\n$}{}ms;
-
-		push @logdata, {
+	    # the first 3 lines of a record contain metadata that looks like this:
+	    # commit abcdefg435768938de
+	    # Author: Jane Doe <email@example.com>
+	    # Date:   1504881409
+
+	    if ($line =~ m{^commit (.+)}) {
+		# Second and subsequent record, push a result
+		if ($first_record_done) {
+		    _debug "pushing a record (rev $revision)";
+		    push @logdata, {
 			'rev'     => $revision,
-			'author'  => $author,
-            'date'    => $date,
-			'message' => $logmessage,
-		};
+		        'author'  => $author,
+			'date'    => $date,
+			'message' => $message,
+		    };
+		    $message = "";
+		}
+		$first_record_done = 1;
+		$revision = $1;
+	    } elsif ($line =~ m{^Author: (.+)}) {
+		$author = $1;
+	    } elsif ($line =~ m{^Date: (.+)}) {
+		$date = $1;
+	    } else {
+		# Lose leading whitespace, but retain blank lines
+		if ($line =~ m{\S}) {
+		    $line =~ s{^\s+}{};
+		}
+		$message .= $line;
+	    }
+
 	}
 	close( $git );
 
-	return reverse @logdata;
+	if ($first_record_done) {
+	    #	_debug "pushing last record (rev $revision)";
+	    # Last record, push a result
+	    push @logdata, {
+		'rev'     => $revision,
+		 'author'  => $author,
+		 'date'    => $date,
+		 'message' => $message,
+	    };
+	    return reverse @logdata;
+	}
+	return undef;
 }
 
-=item vcs_get_diff
+=item get_diff
 
 Returns a hash of (filename,diff) pairs containing the unified diff between two version of a (number of) files.
 
@@ -366,17 +636,16 @@ modified) version is diffed against the latest checked in version.
 
 Example use:
 
-   my %diffs = vcs_get_diff( 'foo.wml', '1.4', '1.17' );
-   my %diffs = vcs_get_diff( 'bla.wml', '1.8' );
-   my %diffs = vcs_get_diff( 'bas.wml' );
+   my %diffs = get_diff( 'foo.wml', '1.4', '1.17' );
+   my %diffs = get_diff( 'bla.wml', '1.8' );
+   my %diffs = get_diff( 'bas.wml' );
    
 
-FIXME: converted using git log format, probably does not work. Needs review and test
-
 =cut
 
-sub vcs_get_diff
+sub get_diff
 {
+	my $self = shift;
 	my $file = shift  or  return;
 	my $rev1 = shift;
 	my $rev2 = shift;
@@ -389,36 +658,25 @@ sub vcs_get_diff
 		defined $rev2 ? "$rev2" : '', 
 		$file );
 
-	# set the record separator for git diff output
-	# not sure if the below expression is correct
-	local $/ = "\n" . 'diff --git' . (.+) . "\n";
+#	print "$command\n";
 
 	open( my $git, '-|', $command ) 
 		or croak("Couldn't run `$command': $!");
 
-	# the first "record" is bogus
-	<$git>;
-
 	# read the consecutive records
 	while ( my $record = <$git> )
 	{
 		# remove the record separator from the end of the record
-		$record =~ s{ $/ \n? \Z }{}msx;
+#		$record =~ s{ $/ \n? \Z }{}msx;
 
 		# remove the "index" line from the beginning of the record
-		$record =~ s{ ^index [^\n] }{}msx;
+#		$record =~ s{ ^index [^\n] }{}msx;
 
 		# remove the first 2 lines
-		$record =~ s{ \A (?: .*? \n ){2} }{}msx;
+		$record =~ s{^diff\s+--git.*}{}msx;
+		$record =~ s{^index\s+.*}{}msx;
 
-		# get the file name
-		if ( not $record =~ m{ \A --- \s+ ([^\t]+) \t }msx )
-		{
-			croak("Parse error in output of `$command'");
-		}
-		my $file = $1;
-
-		$data{$file} = $record;
+		$data{$file} .= $record;
 	}
 	close( $git );
 
@@ -426,7 +684,7 @@ sub vcs_get_diff
 }
 
 
-=item vcs_get_file
+=item get_file
 
 Return a particular revision of a file
 
@@ -438,14 +696,13 @@ and returns it (without writing anything in the current checked-out tree)
 
 Example use:
 
-   my $text = vcs_get_file( 'foo.c', '1.12' );
-
-FIXME: converted to use git show <commit>:<pathname>. Assumes we provide in $file the complete path. Needs review and test
+   my $text = get_file( 'foo.c', '1.12' );
 
 =cut
 
-sub vcs_get_file
+sub get_file
 {
+	my $self = shift;
 	my $file = shift or croak("No file specified");
 	my $rev  = shift or croak("No revision specified");
 
@@ -456,8 +713,8 @@ sub vcs_get_file
 		$rev, $file );
 
 	my $text;
-	open ( my $git, '-|', $command1 ) 
-		or croak("Error while executing `$command1': $!");
+	open ( my $git, '-|', $command ) 
+		or croak("Error while executing `$command': $!");
 	while ( my $line = <$git> )
 	{
 		$text .= $line;
@@ -469,70 +726,147 @@ sub vcs_get_file
 	return $text;
 }
 
-=item vcs_get_topdir
+=item get_oldest_revision
 
-Return the top dir of the webwml repository
+Return the version of the oldest version of a file
 
-The first argument is a name of a checked-out file or directory.
-If it is not specified, by default the current directory is used.
+The first argument is a name of a file.
+
+This function finds the oldest revision of a file that is known in the repository and returns it.
 
 Example use:
 
-   my $dir = vcs_get_topdir( 'foo.c' );
+   my $rev = get_oldest_revision( 'foo.c');
 
 =cut
 
-sub vcs_get_topdir
+sub get_oldest_revision
 {
-	my $file = shift || '.';
-
-	my $git = Local::Gitinfo->new();
-	$git->readinfo( $file );
-	my $root = $git->topdir()
-		or croak ("Unable to determine top-level directory");
+	my $self = shift;
+	my $file = shift or croak("No file specified");
 
-	# TODO: add some check that this really is the top level dir
+	croak( "No such file: $file" ) unless -f $file;
 
-	return $root;
+	my @commits = $self->_grab_commits($file);
+	if (@commits) {
+	    # Simply return the last revision in our list
+	    return $commits[$#commits]{'cmt_rev'};
+	}
+	# Should hopefully never get here!
+	croak(" Could not find any revisions for $file");
 }
 
+=item next_revision
 
+Given a file path and a current revision of that file, move backwards
+or forwards through the commit history and return a related revision.
 
+Takes three arguments: the file path, the start revision and an
+integer to specify which direction to move *and* how far. A negative
+number specifies backwards in history, a positive number specifies
+forwards.
 
+Example use:
 
-######################################
-## internal functions
-######################################
+   my $rev = next_revision( 'foo.c', '72f6700577c79e6d284fbeac44366f6aa357d56d', -1);
 
+Returns the requested revision if it exists, otherwise *undef*
 
-# return the type of the input argument (file, dir, symlink, etc)
-sub _typeoffile
+=cut
+sub next_revision
 {
-	my $file = shift  or  return;
+	# For the file we're looking at, we can easily generate an
+	# array (list) of all the commit hashes. Then we can see where
+	# in that list the specified revision lies.
+
+	my $self = shift;
+	my $file = shift or return undef;
+	my $rev1 = shift or return undef;
+	my $move = shift or return undef;
+
+	my @commits = $self->_grab_commits($file);
+#	print Dumper(@commits);
+	my $pos1 = -1;
+	my $pos2 = -1;
+	my $count = 0;
+	my %entry;
+	foreach my $tmp(@commits) {
+	    %entry = %$tmp;
+	    if ($entry{'cmt_rev'} =~ /\Q$rev1\E/) {
+		$pos1 = $count;
+	    }
+	    if ($pos1 != -1) {
+		last;
+	    }
+	    $count++;
+	}
 
-	stat $file  or  croak("Couldn't stat file `$file'");
+	if ($pos1 == -1) {
+	    # Can't find the specified revision
+	    return undef;
+	}
 
-	return 'f'  if ( -f _ );
-	return 'd'  if ( -d _ );
-	return 'l'  if ( -l _ );
-	return 'S'  if ( -S _ );
-	return 'p'  if ( -p _ );
-	return 'b'  if ( -b _ );
-	return 'c'  if ( -c _ );
+	# API specifies -ve as older, but out list is sorted the other
+	# way...
+	$pos2 = $pos1 - $move;
 
-	return '';
+	if ($pos2 < 0 or $pos2 >= $#commits) {
+	    # Out of range when looking for the new revision
+	    return undef;
+	}
+
+	return $commits[$pos2]{'cmt_rev'};
 }
 
+=item get_topdir
+
+Return the top dir of the webwml repository
+
+The first argument is a name of a checked-out file or directory.
+If it is not specified, by default the current directory is used.
+
+Example use:
+
+   my $dir = get_topdir( 'foo.c' );
+
+=cut
+
+sub get_topdir
+{
+	my $self = shift;
+	my $file = shift || '.';
+
+	# Are we in topdir? Easy!
+	if (-d ".git") {
+	    return ".";
+	}
+
+	# Otherwise, walk up the tree until we find a .git or hit the
+	# root directory
+	my $dir = "..";
+	my ($root_dev, $root_ino) = stat("/");
+
+	while (1 == 1) {
+	    if (-d "$dir/.git") {
+		return "$dir";
+	    }
+	    my ($dev, $ino) = stat("$dir");
+	    if ($root_dev == $dev and $root_ino == $ino) {
+		croak ("Unable to determine top-level directory");
+	    }
+	    $dir = "../$dir";
+	}
+}
 
 =back
 
 =head1 AUTHOR
 
-Copyright (C) 2008  Bas Zoetekouw <bas@debian.org>
+Copyright (C) 2018  Steve McIntyre <93sam@debian.org>
 
-This program is free software; you can redistribute it and/or modify it under
-the terms of version2 of the GNU General Public License as published by the
-Free Software Foundation.
+This program is free software; you can redistribute it and/or modify
+it under the terms of version 2 of the GNU General Public License as
+published by the Free Software Foundation.
 
 =cut
 
diff --git a/Perl/Webwml/Langs.pm b/Perl/Webwml/Langs.pm
index 4df3ecb6631..16857146ff2 100644
--- a/Perl/Webwml/Langs.pm
+++ b/Perl/Webwml/Langs.pm
@@ -34,7 +34,7 @@ the list of languages in which Debian web site is translated.
 package Webwml::Langs;
 
 use Carp;
-use Local::VCS 'vcs_get_topdir';
+use Local::VCS;
 
 use strict;
 use warnings;
@@ -52,13 +52,14 @@ determined from VCS meta-info.
 sub new {
 	my $proto = shift;
 	my $class = ref($proto) || $proto;
+	my $VCS = Local::VCS->new();
 	my $root;
 	if (@_)
 	{
 		$root = shift;
 	} else
 	{
-		$root = vcs_get_topdir;
+		$root = $VCS->get_topdir();
 	}
 	my $self = _read($root);
 	bless ($self, $class);
@@ -72,7 +73,7 @@ sub new {
 # TODO: or rather define the lnaguages in a module, and include those in
 #       languages.wml
 sub _read {
-	my $root = shift || vcs_get_topdir;
+	my $root = shift || Local::VCS->get_topdir();
 
 	open( my $file, '<', "$root/english/template/debian/languages.wml")
 		or croak ("Unable to read $root/english/template/debian/languages.wml");
diff --git a/Perl/Webwml/TransIgnore.pm b/Perl/Webwml/TransIgnore.pm
index d3f6b7e9234..a06f987ff87 100644
--- a/Perl/Webwml/TransIgnore.pm
+++ b/Perl/Webwml/TransIgnore.pm
@@ -33,7 +33,7 @@ package Webwml::TransIgnore;
 
 use Carp;
 use File::Spec::Functions;
-use Local::VCS  qw{ vcs_get_topdir };
+use Local::VCS;
 
 use strict;
 use warnings;
@@ -64,7 +64,8 @@ sub new
 	bless ($self, $class);
 
 	# determine the root dir
-	my $root = shift || vcs_get_topdir('.');
+	my $VCS = Local::VCS->new();
+	my $root = shift || $VCS->get_topdir('.');
 
 	# Read global .transignore file
 	$self->_read($root);