Re: [PATCH] Don't checkout the full tree if avoidable

From

EWEric Wong <normalperson@yhbt.net>

Date

Oct 1, 2007, 11:08 UTC

Message-ID

<20071001110855.GB10079@muzzle>

In-Reply-To

<7vejgftgef.fsf@gitster.siamese.dyndns.org>

Junio C Hamano <gitster@pobox.com> wrote:

> Steven Walter <stevenrwalter@gmail.com> writes:
>
> > In most cases of branching, the tree is copied unmodified from the trunk
> > to the branch.  When that is done, we can simply start with the parent's
> > index and apply the changes on the branch as usual.
> >
> > Signed-off-by: Steven Walter <stevenrwalter@gmail.com>
>
> Eric, do you like this one?

Steven Walter wrote:

> One criticism of the patch: the trees_match function probably needs to
> be re-written.  My SVN::Perl-foo is weak.

Yep :)

Steven:

From: Steven Walter <stevenrwalter@gmail.com>
Date: Fri, 28 Sep 2007 13:24:19 -0400
Subject: [PATCH] Don't checkout the full tree if avoidable

[ew: rewritten from Steven's original to use SVN::Client instead
     of the command-line svn client.

     Since SVN::Client connects separately, we'll share our
     authentication providers array between our usages of
     SVN::Client and SVN::Ra, too.  Bypassing the high-level
     SVN::Client library can avoid this, but the code will be
     much more complex.  Regardless, any implementation of this
     seems to require restarting a connection to the remote
     server.

     Also of note is that SVN 1.4 and later allows a more
     efficient diff_summary to be done instead of a full diff,
     but since this code is only to support SVN < 1.4.4, we'll
     ignore it for now.]

Signed-off-by: Steven Walter <stevenrwalter@gmail.com>
Signed-off-by: Eric Wong <normalperson@yhbt.net>
---
 git-svn.perl |   64 +++++++++++++++++++++++++++++++++++++++++++--------------
 1 files changed, 48 insertions(+), 16 deletions(-)

diff --git a/git-svn.perl b/git-svn.perl
index 484b057..777e436 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -1847,6 +1847,16 @@ sub find_parent_branch {
 			$gs->ra->gs_do_switch($r0, $rev, $gs,
 					      $self->full_url, $ed)
 			  or die "SVN connection failed somewhere...\n";
+		} elsif ($self->ra->trees_match($new_url, $r0,
+			                        $self->full_url, $rev)) {
+			print STDERR "Trees match:\n",
+			             "  $new_url\@$r0\n",
+			             "  ${\$self->full_url}\@$rev\n",
+				     "Following parent with no changes\n";
+			$self->tmp_index_do(sub {
+			    command_noisy('read-tree', $parent);
+			});
+			$self->{last_commit} = $parent;
 		} else {
 			print STDERR "Following parent with do_update\n";
 			$ed = SVN::Git::Fetcher->new($self);
@@ -3027,28 +3037,32 @@ BEGIN {
 	}
 }
 
+sub _auth_providers () {
+	[
+	  SVN::Client::get_simple_provider(),
+	  SVN::Client::get_ssl_server_trust_file_provider(),
+	  SVN::Client::get_simple_prompt_provider(
+	    \&Git::SVN::Prompt::simple, 2),
+	  SVN::Client::get_ssl_client_cert_file_provider(),
+	  SVN::Client::get_ssl_client_cert_prompt_provider(
+	    \&Git::SVN::Prompt::ssl_client_cert, 2),
+	  SVN::Client::get_ssl_client_cert_pw_prompt_provider(
+	    \&Git::SVN::Prompt::ssl_client_cert_pw, 2),
+	  SVN::Client::get_username_provider(),
+	  SVN::Client::get_ssl_server_trust_prompt_provider(
+	    \&Git::SVN::Prompt::ssl_server_trust),
+	  SVN::Client::get_username_prompt_provider(
+	    \&Git::SVN::Prompt::username, 2)
+	]
+}
+
 sub new {
 	my ($class, $url) = @_;
 	$url =~ s!/+$!!;
 	return $RA if ($RA && $RA->{url} eq $url);
 
 	SVN::_Core::svn_config_ensure($config_dir, undef);
-	my ($baton, $callbacks) = SVN::Core::auth_open_helper([
-	    SVN::Client::get_simple_provider(),
-	    SVN::Client::get_ssl_server_trust_file_provider(),
-	    SVN::Client::get_simple_prompt_provider(
-	      \&Git::SVN::Prompt::simple, 2),
-	    SVN::Client::get_ssl_client_cert_file_provider(),
-	    SVN::Client::get_ssl_client_cert_prompt_provider(
-	      \&Git::SVN::Prompt::ssl_client_cert, 2),
-	    SVN::Client::get_ssl_client_cert_pw_prompt_provider(
-	      \&Git::SVN::Prompt::ssl_client_cert_pw, 2),
-	    SVN::Client::get_username_provider(),
-	    SVN::Client::get_ssl_server_trust_prompt_provider(
-	      \&Git::SVN::Prompt::ssl_server_trust),
-	    SVN::Client::get_username_prompt_provider(
-	      \&Git::SVN::Prompt::username, 2),
-	  ]);
+	my ($baton, $callbacks) = SVN::Core::auth_open_helper(_auth_providers);
 	my $config = SVN::Core::config_get_config($config_dir);
 	$RA = undef;
 	my $self = SVN::Ra->new(url => $url, auth => $baton,
@@ -3112,6 +3126,24 @@ sub get_log {
 	$ret;
 }
 
+sub trees_match {
+	my ($self, $url1, $rev1, $url2, $rev2) = @_;
+	my $ctx = SVN::Client->new(auth => _auth_providers);
+	my $out = IO::File->new_tmpfile;
+
+	# older SVN (1.1.x) doesn't take $pool as the last parameter for
+	# $ctx->diff(), so we'll create a default one
+	my $pool = SVN::Pool->new_default_sub;
+
+	$ra_invalid = 1; # this will open a new SVN::Ra connection to $url1
+	$ctx->diff([], $url1, $rev1, $url2, $rev2, 1, 1, 0, $out, $out);
+	$out->flush;
+	my $ret = (($out->stat)[7] == 0);
+	close $out or croak $!;
+
+	$ret;
+}
+
 sub get_commit_editor {
 	my ($self, $log, $cb, $pool) = @_;
 	my @lock = $SVN::Core::VERSION ge '1.2.0' ? (undef, 0) : ();

-- 
Eric Wong