git-svn: persistent memoization

Make memoization of the svn:mergeinfo processing functions persistent with
Memoize::Storable so that the memoization tables don't need to be regenerated
every time the user runs git-svn fetch.

The Memoize::Storable hashes are stored in ENV{GIT_DIR}/svn/.caches.

[ew: changed caches path to avoid conflicts with old repos]
[ew: File::Path::{make_path => mkpath} for compatibility]
[ew: line-wrapped at 80 chars]

Acked-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Andrew Myrick <amyrick@apple.com>

diff --git a/git-svn.perl b/git-svn.perl
index 4f7dc2b73b75dfed0aac5860c77117559cdd3bcd..265852f4596bfe5aeca12be06f78631320b8ebb4 100755 (executable)
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -1656,6 +1656,7 @@ use File::Path qw/mkpath/;
 use File::Copy qw/copy/;
 use IPC::Open3;
 use Memoize;  # core since 5.8.0, Jul 2002
+use Memoize::Storable;
 
 my ($_gc_nr, $_gc_period);
 
@@ -3116,10 +3117,39 @@ sub has_no_changes {
                command_oneline("rev-parse", "$commit~1^{tree}"));
 }
 
-BEGIN {
-       memoize 'lookup_svn_merge';
-       memoize 'check_cherry_pick';
-       memoize 'has_no_changes';
+# The GIT_DIR environment variable is not always set until after the command
+# line arguments are processed, so we can't memoize in a BEGIN block.
+{
+       my $memoized = 0;
+
+       sub memoize_svn_mergeinfo_functions {
+               return if $memoized;
+               $memoized = 1;
+
+               my $cache_path = "$ENV{GIT_DIR}/svn/.caches/";
+               mkpath([$cache_path]) unless -d $cache_path;
+
+               tie my %lookup_svn_merge_cache => 'Memoize::Storable',
+                   "$cache_path/lookup_svn_merge.db", 'nstore';
+               memoize 'lookup_svn_merge',
+                       SCALAR_CACHE => 'FAULT',
+                       LIST_CACHE => ['HASH' => \%lookup_svn_merge_cache],
+               ;
+
+               tie my %check_cherry_pick_cache => 'Memoize::Storable',
+                   "$cache_path/check_cherry_pick.db", 'nstore';
+               memoize 'check_cherry_pick',
+                       SCALAR_CACHE => 'FAULT',
+                       LIST_CACHE => ['HASH' => \%check_cherry_pick_cache],
+               ;
+
+               tie my %has_no_changes_cache => 'Memoize::Storable',
+                   "$cache_path/has_no_changes.db", 'nstore';
+               memoize 'has_no_changes',
+                       SCALAR_CACHE => ['HASH' => \%has_no_changes_cache],
+                       LIST_CACHE => 'FAULT',
+               ;
+       }
 }
 
 sub parents_exclude {
@@ -3163,6 +3193,8 @@ sub find_extra_svn_parents {
        my ($self, $ed, $mergeinfo, $parents) = @_;
        # aha!  svk:merge property changed...
 
+       memoize_svn_mergeinfo_functions();
+
        # We first search for merged tips which are not in our
        # history.  Then, we figure out which git revisions are in
        # that tip, but not this revision.  If all of those revisions