git-svn: enable delta transfers during fetches when using SVN:: libs

This should drastically reduce bandwidth used for network
transfers.  This is not enabled for file:// repositories by
default because of the increased CPU usage and I/O needed.

GIT_SVN_DELTA_FETCH may be set to a true value to enable or
false (0) to disable delta transfers regardless of the
repository type.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/git-svn.perl b/git-svn.perl
index d5d9c49fd6c06ceb20bb057f6d3ad2e99414a69f..9b86d91266909fe70064f73faef3ac73f23e3993 100755 (executable)
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -68,7 +68,7 @@ my ($_revision,$_stdin,$_no_ignore_ext,$_no_stop_copy,$_help,$_rmdir,$_edit,
        $_limit, $_verbose, $_incremental, $_oneline, $_l_fmt, $_show_commit,
        $_version, $_upgrade, $_authors, $_branch_all_refs, @_opt_m,
        $_merge, $_strategy, $_dry_run, $_ignore_nodate, $_non_recursive,
-       $_username, $_config_dir, $_no_auth_cache);
+       $_username, $_config_dir, $_no_auth_cache, $_xfer_delta);
 my (@_branch_from, %tree_map, %users, %rusers, %equiv);
 my ($_svn_co_url_revs, $_svn_pg_peg_revs);
 my @repo_path_split_cache;
@@ -2675,6 +2675,9 @@ sub libsvn_load {
                require SVN::Ra;
                require SVN::Delta;
                push @SVN::Git::Editor::ISA, 'SVN::Delta::Editor';
+               push @SVN::Git::Fetcher::ISA, 'SVN::Delta::Editor';
+               *SVN::Git::Fetcher::process_rm = *process_rm;
+               *SVN::Git::Fetcher::safe_qx = *safe_qx;
                my $kill_stupid_warnings = $SVN::Node::none.$SVN::Node::file.
                                        $SVN::Node::dir.$SVN::Node::unknown.
                                        $SVN::Node::none.$SVN::Node::file.
@@ -2827,6 +2830,13 @@ sub libsvn_connect {
                              config => $config,
                              pool => SVN::Pool->new,
                              auth_provider_callbacks => $callbacks);
+
+       my $df = $ENV{GIT_SVN_DELTA_FETCH};
+       if (defined $df) {
+               $_xfer_delta = $df;
+       } else {
+               $_xfer_delta = ($url =~ m#^file://#) ? undef : 1;
+       }
        $ra->{svn_path} = $url;
        $ra->{repos_root} = $ra->get_repos_root;
        $ra->{svn_path} =~ s#^\Q$ra->{repos_root}\E/*##;
@@ -2915,6 +2925,24 @@ sub process_rm {
 }
 
 sub libsvn_fetch {
+       $_xfer_delta ? libsvn_fetch_delta(@_) : libsvn_fetch_full(@_);
+}
+
+sub libsvn_fetch_delta {
+       my ($last_commit, $paths, $rev, $author, $date, $msg) = @_;
+       my $pool = SVN::Pool->new;
+       my $ed = SVN::Git::Fetcher->new({ c => $last_commit, ra => $SVN,
+                                         paths => $paths });
+       my $reporter = $SVN->do_update($rev, '', 1, $ed, $pool);
+       my @lock = $SVN::Core::VERSION ge '1.2.0' ? (undef) : ();
+       my (undef, $last_rev, undef) = cmt_metadata($last_commit);
+       $reporter->set_path('', $last_rev, 0, @lock, $pool);
+       $reporter->finish_report($pool);
+       $pool->clear;
+       libsvn_log_entry($rev, $author, $date, $msg, [$last_commit]);
+}
+
+sub libsvn_fetch_full {
        my ($last_commit, $paths, $rev, $author, $date, $msg) = @_;
        open my $gui, '| git-update-index -z --index-info' or croak $!;
        my @amr;
@@ -3133,7 +3161,11 @@ sub libsvn_find_parent_branch {
                unlink $GIT_SVN_INDEX;
                print STDERR "Found branch parent: ($GIT_SVN) $parent\n";
                sys(qw/git-read-tree/, $parent);
-               return libsvn_fetch($parent, $paths, $rev,
+               # I can't seem to get do_switch() to work correctly with
+               # the SWIG interface (TypeError when passing switch_url...),
+               # so we'll unconditionally bypass the delta interface here
+               # for now
+               return libsvn_fetch_full($parent, $paths, $rev,
                                        $author, $date, $msg);
        }
        print STDERR "Nope, branch point not imported or unknown\n";
@@ -3153,9 +3185,19 @@ sub libsvn_new_tree {
                return $log_entry;
        }
        my ($paths, $rev, $author, $date, $msg) = @_;
-       open my $gui, '| git-update-index -z --index-info' or croak $!;
-       libsvn_traverse($gui, '', $SVN->{svn_path}, $rev);
-       close $gui or croak $?;
+       if ($_xfer_delta) {
+               my $pool = SVN::Pool->new;
+               my $ed = SVN::Git::Fetcher->new({paths => $paths, ra => $SVN});
+               my $reporter = $SVN->do_update($rev, '', 1, $ed, $pool);
+               my @lock = $SVN::Core::VERSION ge '1.2.0' ? (undef) : ();
+               $reporter->set_path('', $rev, 1, @lock, $pool);
+               $reporter->finish_report($pool);
+               $pool->clear;
+       } else {
+               open my $gui, '| git-update-index -z --index-info' or croak $!;
+               libsvn_traverse($gui, '', $SVN->{svn_path}, $rev);
+               close $gui or croak $?;
+       }
        return libsvn_log_entry($rev, $author, $date, $msg);
 }
 
@@ -3325,6 +3367,148 @@ sub copy_remote_ref {
                                "refs/remotes/$GIT_SVN on $origin\n";
        }
 }
+package SVN::Git::Fetcher;
+use vars qw/@ISA/;
+use strict;
+use warnings;
+use Carp qw/croak/;
+use IO::File qw//;
+
+# file baton members: path, mode_a, mode_b, pool, fh, blob, base
+sub new {
+       my ($class, $git_svn) = @_;
+       my $self = SVN::Delta::Editor->new;
+       bless $self, $class;
+       open my $gui, '| git-update-index -z --index-info' or croak $!;
+       $self->{gui} = $gui;
+       $self->{c} = $git_svn->{c} if exists $git_svn->{c};
+       if (my $p = $git_svn->{paths} && $git_svn->{ra}) {
+               my $s = $git_svn->{ra}->{svn_path};
+               $s = length $s ? qr#^/\Q$s\E/# : qr#^/#;
+               $self->{paths} = { map { my $x = $_;
+                                        $x =~ s/$s//;
+                                        $x => $p->{$_} } keys %$p };
+       }
+       require Digest::MD5;
+       $self;
+}
+
+sub delete_entry {
+       my ($self, $path, $rev, $pb) = @_;
+       process_rm($self->{gui}, $self->{c}, $path);
+       undef;
+}
+
+sub open_file {
+       my ($self, $path, $pb, $rev) = @_;
+       my ($mode, $blob) = (safe_qx('git-ls-tree',$self->{c},'--',$path)
+                            =~ /^(\d{6}) blob ([a-f\d]{40})\t/);
+       { path => $path, mode_a => $mode, mode_b => $mode, blob => $blob,
+         pool => SVN::Pool->new };
+}
+
+sub add_file {
+       my ($self, $path, $pb, $cp_path, $cp_rev) = @_;
+       { path => $path, mode_a => 100644, mode_b => 100644,
+         pool => SVN::Pool->new };
+}
+
+sub change_file_prop {
+       my ($self, $fb, $prop, $value) = @_;
+       if ($prop eq 'svn:executable') {
+               if ($fb->{mode_b} != 120000) {
+                       $fb->{mode_b} = defined $value ? 100755 : 100644;
+               }
+       } elsif ($prop eq 'svn:special') {
+               $fb->{mode_b} = defined $value ? 120000 : 100644;
+       }
+       undef;
+}
+
+sub apply_textdelta {
+       my ($self, $fb, $exp) = @_;
+       my $fh = IO::File->new_tmpfile;
+       $fh->autoflush(1);
+       # $fh gets auto-closed() by SVN::TxDelta::apply(),
+       # (but $base does not,) so dup() it for reading in close_file
+       open my $dup, '<&', $fh or croak $!;
+       my $base = IO::File->new_tmpfile;
+       $base->autoflush(1);
+       if ($fb->{blob}) {
+               defined (my $pid = fork) or croak $!;
+               if (!$pid) {
+                       open STDOUT, '>&', $base or croak $!;
+                       print STDOUT 'link ' if ($fb->{mode_a} == 120000);
+                       exec qw/git-cat-file blob/, $fb->{blob} or croak $!;
+               }
+               waitpid $pid, 0;
+               croak $? if $?;
+
+               if (defined $exp) {
+                       seek $base, 0, 0 or croak $!;
+                       my $md5 = Digest::MD5->new;
+                       $md5->addfile($base);
+                       my $got = $md5->hexdigest;
+                       die "Checksum mismatch: $fb->{path} $fb->{blob}\n",
+                           "expected: $exp\n",
+                           "     got: $got\n" if ($got ne $exp);
+               }
+       }
+       seek $base, 0, 0 or croak $!;
+       $fb->{fh} = $dup;
+       $fb->{base} = $base;
+       [ SVN::TxDelta::apply($base, $fh, undef, $fb->{path}, $fb->{pool}) ];
+}
+
+sub close_file {
+       my ($self, $fb, $exp) = @_;
+       my $hash;
+       my $path = $fb->{path};
+       if (my $fh = $fb->{fh}) {
+               seek($fh, 0, 0) or croak $!;
+               my $md5 = Digest::MD5->new;
+               $md5->addfile($fh);
+               my $got = $md5->hexdigest;
+               die "Checksum mismatch: $path\n",
+                   "expected: $exp\n    got: $got\n" if ($got ne $exp);
+               seek($fh, 0, 0) or croak $!;
+               if ($fb->{mode_b} == 120000) {
+                       read($fh, my $buf, 5) == 5 or croak $!;
+                       $buf eq 'link ' or die "$path has mode 120000",
+                                              "but is not a link\n";
+               }
+               defined(my $pid = open my $out,'-|') or die "Can't fork: $!\n";
+               if (!$pid) {
+                       open STDIN, '<&', $fh or croak $!;
+                       exec qw/git-hash-object -w --stdin/ or croak $!;
+               }
+               chomp($hash = do { local $/; <$out> });
+               close $out or croak $!;
+               close $fh or croak $!;
+               $hash =~ /^[a-f\d]{40}$/ or die "not a sha1: $hash\n";
+               close $fb->{base} or croak $!;
+       } else {
+               $hash = $fb->{blob} or die "no blob information\n";
+       }
+       $fb->{pool}->clear;
+       my $gui = $self->{gui};
+       print $gui "$fb->{mode_b} $hash\t$path\0" or croak $!;
+       print "\t", $self->{paths}->{$path}->action,
+             "\t$path\n" if defined $self->{paths}->{$path};
+       undef;
+}
+
+sub abort_edit {
+       my $self = shift;
+       close $self->{gui};
+       $self->SUPER::abort_edit(@_);
+}
+
+sub close_edit {
+       my $self = shift;
+       close $self->{gui} or croak;
+       $self->SUPER::close_edit(@_);
+}
 
 package SVN::Git::Editor;
 use vars qw/@ISA/;