git-svn: lazy load some modules

We can delay loading some modules until we need them for uncommon
code paths.  For example, persistent memoization is not often
needed, so we can avoid loading the modules for it until we
encounter svn::mergeinfo during fetch.

This gives a tiny reduction in syscalls (from 15641 to 15305) when
running "git svn info" and counting via "strace -fc".  Further,
more invasive work will be needed to noticeably improve performance.

Signed-off-by: Eric Wong <normalperson@yhbt.net>

1 files changed, 7 insertions, 6 deletions

diff --git a/git-svn.perl b/git-svn.perl
index 32d109ebdf..36f7240c99 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -11,14 +11,10 @@ $AUTHOR = 'Eric Wong <normalperson@yhbt.net>';
 $VERSION = '@@GIT_VERSION@@';
 
 use Carp qw/croak/;
-use Digest::MD5;
-use IO::File qw//;
 use File::Basename qw/dirname basename/;
 use File::Path qw/mkpath/;
 use File::Spec;
-use File::Find;
 use Getopt::Long qw/:config gnu_getopt no_ignore_case auto_abbrev/;
-use IPC::Open3;
 use Memoize;
 
 use Git::SVN;
@@ -298,7 +294,6 @@ my %cmd = (
 		{} ],
 );
 
-use Term::ReadLine;
 package FakeTerm;
 sub new {
 	my ($class, $reason) = @_;
@@ -313,6 +308,7 @@ package main;
 my $term;
 sub term_init {
 	$term = eval {
+		require Term::ReadLine;
 		$ENV{"GIT_SVN_NOTTY"}
 			? new Term::ReadLine 'git-svn', \*STDIN, \*STDOUT
 			: new Term::ReadLine 'git-svn';
@@ -1173,6 +1169,7 @@ sub cmd_branch {
 	}
 
 	::_req_svn();
+	require SVN::Client;
 
 	my $ctx = SVN::Client->new(
 		config => SVN::Core::config_get_config(
@@ -1693,11 +1690,13 @@ sub cmd_reset {
 }
 
 sub cmd_gc {
+	require File::Find;
 	if (!can_compress()) {
 		warn "Compress::Zlib could not be found; unhandled.log " .
 		     "files will not be compressed.\n";
 	}
-	find({ wanted => \&gc_directory, no_chdir => 1}, "$ENV{GIT_DIR}/svn");
+	File::Find::find({ wanted => \&gc_directory, no_chdir => 1},
+			 "$ENV{GIT_DIR}/svn");
 }
 
 ########################### utility functions #########################
@@ -2122,6 +2121,7 @@ sub find_file_type_and_diff_status {
 sub md5sum {
 	my $arg = shift;
 	my $ref = ref $arg;
+	require Digest::MD5;
 	my $md5 = Digest::MD5->new();
         if ($ref eq 'GLOB' || $ref eq 'IO::File' || $ref eq 'File::Temp') {
 		$md5->addfile($arg) or croak $!;
@@ -2148,6 +2148,7 @@ sub gc_directory {
 			$gz->gzwrite($str) or
 				die "Unable to write: ".$gz->gzerror()."!\n";
 		}
+		no warnings 'once'; # $File::Find::name would warn
 		unlink $_ or die "unlink $File::Find::name: $!\n";
 	} elsif (-f $_ && basename($_) eq "index") {
 		unlink $_ or die "unlink $_: $!\n";