[PATCH/RFC v4 3/7] gettext: Add a Gettext interface for Perl

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Make Git's gettext messages available to Perl programs through
Locale::Messages. Gracefully fall back to English on systems that
don't contain the module.

This contains some makefile hacks to pass localedir to
perl/Makefile. Which in turn passes it to perl.mak, which'll use it to
search/replace occurances of ++LOCALEDIR++ in .pm files.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 Makefile            |    6 +++-
 git-send-email.perl |    3 +-
 perl/Git/I18N.pm    |   73 +++++++++++++++++++++++++++++++++++++++++++++++++++
 perl/Makefile       |    3 +-
 perl/Makefile.PL    |   14 +++++++++-
 5 files changed, 94 insertions(+), 5 deletions(-)
 create mode 100644 perl/Git/I18N.pm

diff --git a/Makefile b/Makefile
index dce2faa..3f0e305 100644
--- a/Makefile
+++ b/Makefile
@@ -1505,7 +1505,7 @@ ifndef NO_TCLTK
 	$(QUIET_SUBDIR0)gitk-git $(QUIET_SUBDIR1) all
 endif
 ifndef NO_PERL
-	$(QUIET_SUBDIR0)perl $(QUIET_SUBDIR1) PERL_PATH='$(PERL_PATH_SQ)' prefix='$(prefix_SQ)' all
+	$(QUIET_SUBDIR0)perl $(QUIET_SUBDIR1) PERL_PATH='$(PERL_PATH_SQ)' prefix='$(prefix_SQ)' localedir='$(localedir_SQ)' all
 endif
 ifndef NO_PYTHON
 	$(QUIET_SUBDIR0)git_remote_helpers $(QUIET_SUBDIR1) PYTHON_PATH='$(PYTHON_PATH_SQ)' prefix='$(prefix_SQ)' all
@@ -1884,7 +1884,9 @@ cscope:
 	$(FIND) . -name '*.[hcS]' -print | xargs cscope -b
 
 pot:
-	$(XGETTEXT) -k_ -o po/git.pot $(C_OBJ:o=c) $(SCRIPT_SH)
+	$(XGETTEXT) --keyword=_ --output=po/git.pot --language=C $(C_OBJ:o=c)
+	$(XGETTEXT) --join-existing --output=po/git.pot --language=Shell $(SCRIPT_SH)
+	$(XGETTEXT) --join-existing --output=po/git.pot --language=Perl $(SCRIPT_PERL)
 
 POFILES := $(wildcard po/*.po)
 MOFILES := $(patsubst po/%.po,share/locale/%/LC_MESSAGES/git.mo,$(POFILES))
diff --git a/git-send-email.perl b/git-send-email.perl
index 111c981..b9288af 100755
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -26,6 +26,7 @@ use Term::ANSIColor;
 use File::Temp qw/ tempdir tempfile /;
 use Error qw(:try);
 use Git;
+use Git::I18N;
 
 Getopt::Long::Configure qw/ pass_through /;
 
@@ -674,7 +675,7 @@ if (!defined $sender) {
 	$sender = $repoauthor || $repocommitter || '';
 	$sender = ask("Who should the emails appear to be from? [$sender] ",
 	              default => $sender);
-	print "Emails will be sent from: ", $sender, "\n";
+	printf gettext("Emails will be sent from: %s\n"), $sender;
 	$prompting++;
 }
 
diff --git a/perl/Git/I18N.pm b/perl/Git/I18N.pm
new file mode 100644
index 0000000..e19d99b
--- /dev/null
+++ b/perl/Git/I18N.pm
@@ -0,0 +1,73 @@
+package Git::I18N;
+use strict;
+use warnings;
+use Exporter;
+use base 'Exporter';
+
+our $VERSION = '0.01';
+
+our @EXPORT = qw(gettext);
+our @EXPORT_OK = @EXPORT;
+
+sub __bootstrap_locale_messages {
+	our $TEXTDOMAIN = 'git';
+	our $TEXTDOMAINDIR = $ENV{GIT_TEXTDOMAINDIR} || '++LOCALEDIR++';
+
+	require POSIX;
+	POSIX->import(qw(setlocale));
+	# Non-core prerequisite module
+	require Locale::Messages;
+	Locale::Messages->import(qw(:locale_h :libintl_h));
+
+	setlocale(LC_MESSAGES(), '');
+	setlocale(LC_CTYPE(), '');
+	textdomain($TEXTDOMAIN);
+	bindtextdomain($TEXTDOMAIN => $TEXTDOMAINDIR);
+
+	return;
+}
+
+BEGIN
+{
+	local ($@, $!);
+	eval { __bootstrap_locale_messages() };
+	if ($@) {
+		# Oh noes, no Locale::Messages here
+		*gettext = sub ($) { $_[0] };
+	}
+}
+
+1;
+
+__END__
+
+=head1 NAME
+
+Git::I18N - Perl interface to Git's Gettext localizations
+
+=head1 SYNOPSIS
+
+	use Git::I18N;
+
+	print gettext("Welcome to Git!\n");
+
+	printf gettext("The following error occured: %s\n"), $error;
+
+=head1 DESCRIPTION
+
+Git's internal interface to Gettext via L<Locale::Messages>. If
+L<Locale::Messages> can't be loaded (it's not a core module) we
+provide stub passthrough fallbacks.
+
+=head1 FUNCTIONS
+
+=head2 gettext($)
+
+L<Locale::Messages>'s gettext function if all goes well, otherwise our
+passthrough fallback function.
+
+=head1 AUTHOR
+
+E<AElig>var ArnfjE<ouml>rE<eth> Bjarmason <avarab@gmail.com>
+
+=cut
diff --git a/perl/Makefile b/perl/Makefile
index 4ab21d6..4e624ff 100644
--- a/perl/Makefile
+++ b/perl/Makefile
@@ -5,6 +5,7 @@ makfile:=perl.mak
 
 PERL_PATH_SQ = $(subst ','\'',$(PERL_PATH))
 prefix_SQ = $(subst ','\'',$(prefix))
+localedir_SQ = $(subst ','\'',$(localedir))
 
 ifndef V
 	QUIET = @
@@ -38,7 +39,7 @@ $(makfile): ../GIT-CFLAGS Makefile
 	echo '	echo $(instdir_SQ)' >> $@
 else
 $(makfile): Makefile.PL ../GIT-CFLAGS
-	$(PERL_PATH) $< PREFIX='$(prefix_SQ)'
+	$(PERL_PATH) $< PREFIX='$(prefix_SQ)' --localedir='$(localedir_SQ)'
 endif
 
 # this is just added comfort for calling make directly in perl dir
diff --git a/perl/Makefile.PL b/perl/Makefile.PL
index 0b9deca..456d45b 100644
--- a/perl/Makefile.PL
+++ b/perl/Makefile.PL
@@ -1,4 +1,12 @@
+use strict;
+use warnings;
 use ExtUtils::MakeMaker;
+use Getopt::Long;
+
+# Sanity: die at first unknown option
+Getopt::Long::Configure qw/ pass_through /;
+
+GetOptions("localedir=s" => \my $localedir);
 
 sub MY::postamble {
 	return <<'MAKE_FRAG';
@@ -16,7 +24,10 @@ endif
 MAKE_FRAG
 }
 
-my %pm = ('Git.pm' => '$(INST_LIBDIR)/Git.pm');
+my %pm = (
+	'Git.pm' => '$(INST_LIBDIR)/Git.pm',
+	'Git/I18N.pm' => '$(INST_LIBDIR)/Git/I18N.pm',
+);
 
 # We come with our own bundled Error.pm. It's not in the set of default
 # Perl modules so install it if it's not available on the system yet.
@@ -33,6 +44,7 @@ WriteMakefile(
 	NAME            => 'Git',
 	VERSION_FROM    => 'Git.pm',
 	PM		=> \%pm,
+	PM_FILTER	=> qq[\$(PERL) -pe "s<\\Q++LOCALEDIR++\\E><$localedir>"],
 	MAKEFILE	=> 'perl.mak',
 	INSTALLSITEMAN3DIR => '$(SITEPREFIX)/share/man/man3'
 );
-- 
1.7.1.251.gec7f5.dirty