Merge branch 'ew/rerere'

* ew/rerere:
rerere: record (or avoid misrecording) resolved, skipped or aborted rebase/am
git-rerere: add 'gc' command.
rerere: add clear, diff, and status commands

diff --combined git-rerere.perl
index 2e8dbbd4ea0adcf8aee1e87acfc439e41a7289cf,61eef575da8c499d9e888aeb863e0b8e1ce47a59..fdd68548961247b38e637f61e280ab4084650475
--- 1/git-rerere.perl
--- 2/git-rerere.perl
+++ b/git-rerere.perl
@@@ -154,7 -154,7 +154,7 @@@ sub find_conflict 
  sub merge {
        my ($name, $path) = @_;
        record_preimage($path, "$rr_dir/$name/thisimage");
 -      unless (system('merge', map { "$rr_dir/$name/${_}image" }
 +      unless (system('git merge-file', map { "$rr_dir/$name/${_}image" }
                       qw(this pre post))) {
                my $in;
                open $in, "<$rr_dir/$name/thisimage" or
@@@ -169,9 -169,66 +169,66 @@@
        return 0;
  }
  
+ sub garbage_collect_rerere {
+       # We should allow specifying these from the command line and
+       # that is why the caller gives @ARGV to us, but I am lazy.
+ 
+       my $cutoff_noresolve = 15; # two weeks
+       my $cutoff_resolve = 60; # two months
+       my @to_remove;
+       while (<$rr_dir/*/preimage>) {
+               my ($dir) = /^(.*)\/preimage$/;
+               my $cutoff = ((-f "$dir/postimage")
+                             ? $cutoff_resolve
+                             : $cutoff_noresolve);
+               my $age = -M "$_";
+               if ($cutoff <= $age) {
+                       push @to_remove, $dir;
+               }
+       }
+       if (@to_remove) {
+               rmtree(\@to_remove);
+       }
+ }
+ 
  -d "$rr_dir" || exit(0);
  
  read_rr();
+ 
+ if (@ARGV) {
+       my $arg = shift @ARGV;
+       if ($arg eq 'clear') {
+               for my $path (keys %merge_rr) {
+                       my $name = $merge_rr{$path};
+                       if (-d "$rr_dir/$name" &&
+                           ! -f "$rr_dir/$name/postimage") {
+                               rmtree(["$rr_dir/$name"]);
+                       }
+               }
+               unlink $merge_rr;
+       }
+       elsif ($arg eq 'status') {
+               for my $path (keys %merge_rr) {
+                       print $path, "\n";
+               }
+       }
+       elsif ($arg eq 'diff') {
+               for my $path (keys %merge_rr) {
+                       my $name = $merge_rr{$path};
+                       system('diff', ((@ARGV == 0) ? ('-u') : @ARGV),
+                               '-L', "a/$path", '-L', "b/$path",
+                               "$rr_dir/$name/preimage", $path);
+               }
+       }
+       elsif ($arg eq 'gc') {
+               garbage_collect_rerere(@ARGV);
+       }
+       else {
+               die "$0 unknown command: $arg\n";
+       }
+       exit 0;
+ }
+ 
  my %conflict = map { $_ => 1 } find_conflict();
  
  # MERGE_RR records paths with conflicts immediately after merge