import: switch to "replace_oids" interface for purge

Continuing the work by Eric Biederman in commit a118d58a402bd31b
("Import.pm: When purging replace a purged file with a zero length file"),
we can use a generic OID replacement mechanism to implement
purge.

2 files changed, 22 insertions, 17 deletions

diff --git a/lib/PublicInbox/Import.pm b/lib/PublicInbox/Import.pm
index 6ee1935e..2c8fe848 100644
--- a/lib/PublicInbox/Import.pm
+++ b/lib/PublicInbox/Import.pm
@@ -501,16 +501,16 @@ sub clean_purge_buffer {
         }
 }
 
-sub purge_oids {
-        my ($self, $purge) = @_;
-        my $tmp = "refs/heads/purge-".((keys %$purge)[0]);
+sub replace_oids {
+        my ($self, $replace) = @_; # oid => raw string
+        my $tmp = "refs/heads/replace-".((keys %$replace)[0]);
         my $old = $self->{'ref'};
         my $git = $self->{git};
         my @export = (qw(fast-export --no-data --use-done-feature), $old);
         my $rd = $git->popen(@export);
         my ($r, $w) = $self->gfi_start;
         my @buf;
-        my $npurge = 0;
+        my $nreplace = 0;
         my @oids;
         my ($done, $mark);
         my $tree = $self->{-tree};
@@ -533,10 +533,13 @@ sub purge_oids {
                 } elsif (/^M 100644 ([a-f0-9]+) (\w+)/) {
                         my ($oid, $path) = ($1, $2);
                         $tree->{$path} = 1;
-                        if ($purge->{$oid}) {
+                        my $sref = $replace->{$oid};
+                        if (defined $sref) {
                                 push @oids, $oid;
-                                my $cmd = "M 100644 inline $path\ndata 0\n\n";
-                                push @buf, $cmd;
+                                my $n = length($$sref);
+                                push @buf, "M 100644 inline $path\ndata $n\n";
+                                push @buf, $$sref; # hope CoW works...
+                                push @buf, "\n";
                         } else {
                                 push @buf, $_;
                         }
@@ -549,7 +552,7 @@ sub purge_oids {
                                 $out =~ s/^/# /sgm;
                                 warn "purge rewriting\n", $out, "\n";
                                 clean_purge_buffer(\@oids, \@buf);
-                                $npurge++;
+                                $nreplace++;
                         }
                         $w->print(@buf, "\n") or wfail;
                         @buf = ();
@@ -567,28 +570,30 @@ sub purge_oids {
                 $w->print(@buf) or wfail;
         }
         die 'done\n not seen from fast-export' unless $done;
-        chomp(my $cmt = $self->get_mark(":$mark")) if $npurge;
+        chomp(my $cmt = $self->get_mark(":$mark")) if $nreplace;
         $self->{nchg} = 0; # prevent _update_git_info until update-ref:
         $self->done;
         my @git = ('git', "--git-dir=$git->{git_dir}");
 
-        run_die([@git, qw(update-ref), $old, $tmp]) if $npurge;
+        run_die([@git, qw(update-ref), $old, $tmp]) if $nreplace;
 
         run_die([@git, qw(update-ref -d), $tmp]);
 
-        return if $npurge == 0;
+        return if $nreplace == 0;
 
         run_die([@git, qw(-c gc.reflogExpire=now gc --prune=all)]);
+
+        # check that old OIDs are gone
         my $err = 0;
-        foreach my $oid (keys %$purge) {
+        foreach my $oid (keys %$replace) {
                 my @info = $git->check($oid);
                 if (@info) {
-                        warn "$oid not purged\n";
+                        warn "$oid not replaced\n";
                         $err++;
                 }
         }
         _update_git_info($self, 0);
-        die "Failed to purge $err object(s)\n" if $err;
+        die "Failed to replace $err object(s)\n" if $err;
         $cmt;
 }
 
diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index a435814a..d6f72b07 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -298,7 +298,7 @@ sub idx_init {
 }
 
 sub purge_oids ($$) {
-        my ($self, $purge) = @_; # $purge = { $object_id => 1, ... }
+        my ($self, $purge) = @_; # $purge = { $object_id => \'', ... }
         $self->done;
         my $pfx = "$self->{-inbox}->{mainrepo}/git";
         my $purges = [];
@@ -313,7 +313,7 @@ sub purge_oids ($$) {
                 -d $git_dir or next;
                 my $git = PublicInbox::Git->new($git_dir);
                 my $im = $self->import_init($git, 0, 1);
-                $purges->[$i] = $im->purge_oids($purge);
+                $purges->[$i] = $im->replace_oids($purge);
                 $im->done;
         }
         $purges;
@@ -386,7 +386,7 @@ sub remove_internal ($$$$) {
                         $removed = $smsg;
                         my $oid = $smsg->{blob};
                         if ($purge) {
-                                $purge->{$oid} = 1;
+                                $purge->{$oid} = \'';
                         } else {
                                 ($mark, undef) = $im->remove($orig, $cmt_msg);
                         }