Dgit.pm: Move reflog_cache_* from dgit

We are going to want this for git-debrebase merge resolutions.

NFC other than the usual change to literal `git'.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

2 files changed, 68 insertions, 44 deletions

diff --git a/Debian/Dgit.pm b/Debian/Dgit.pm
index 69db866..91d4c71 100644
--- a/Debian/Dgit.pm
+++ b/Debian/Dgit.pm
@@ -32,6 +32,7 @@ use IPC::Open2;
 use File::Path;
 use File::Basename;
 use Dpkg::Control::Hash;
+use Debian::Dgit::ExitStatus;
 
 BEGIN {
     use Exporter   ();
@@ -58,6 +59,7 @@ BEGIN {
 		      git_check_unmodified
 		      git_reflog_action_msg  git_update_ref_cmd
 		      make_commit_text
+		      reflog_cache_insert reflog_cache_lookup
                       $package_re $component_re $deliberately_re
 		      $distro_re $versiontag_re $series_filename_re
 		      $orig_f_comp_re $orig_f_sig_re $orig_f_tail_re
@@ -715,6 +717,66 @@ sub make_commit_text ($) {
     return $h;
 }
 
+sub reflog_cache_insert ($$$) {
+    my ($ref, $cachekey, $value) = @_;
+    # you must call this in $maindir
+    # you must have called record_maindir
+
+    # When we no longer need to support squeeze, use --create-reflog
+    # instead of this:
+    my $parent = $ref; $parent =~ s{/[^/]+$}{};
+    ensuredir "$maindir_gitcommon/logs/$parent";
+    my $makelogfh = new IO::File "$maindir_gitcommon/logs/$ref", '>>'
+      or die $!;
+
+    my $oldcache = git_get_ref $ref;
+
+    if ($oldcache eq $value) {
+	my $tree = cmdoutput qw(git rev-parse), "$value:";
+	# git update-ref doesn't always update, in this case.  *sigh*
+	my $authline = (ucfirst _us()).
+	    ' <'._us().'@example.com> 1000000000 +0000';
+	my $dummy = make_commit_text <<END;
+tree $tree
+parent $value
+author $authline
+committer $authline
+
+Dummy commit - do not use
+END
+	runcmd qw(git update-ref -m), _us()." - dummy", $ref, $dummy;
+    }
+    runcmd qw(git update-ref -m), $cachekey, $ref, $value;
+}
+
+sub reflog_cache_lookup ($$) {
+    my ($ref, $cachekey) = @_;
+    # you may call this in $maindir or in a playtree
+    # you must have called record_maindir
+    my @cmd = (qw(git log -g), '--pretty=format:%H %gs', $ref);
+    debugcmd "|(probably)",@cmd;
+    my $child = open GC, "-|";  defined $child or die $!;
+    if (!$child) {
+	chdir $maindir or die $!;
+	if (!stat "$maindir_gitcommon/logs/$ref") {
+	    $! == ENOENT or die $!;
+	    printdebug ">(no reflog)\n";
+	    finish 0;
+	}
+	exec @cmd; die $!;
+    }
+    while (<GC>) {
+	chomp;
+	printdebug ">| ", $_, "\n" if $debuglevel > 1;
+	next unless m/^(\w+) (\S.*\S)$/ && $2 eq $cachekey;
+	close GC;
+	return $1;
+    }
+    die $! if GC->error;
+    failedcmd unless close GC;
+    return undef;
+}
+
 # ========== playground handling ==========
 
 # terminology:
diff --git a/dgit b/dgit
index 6879e54..991fd9a 100755
--- a/dgit
+++ b/dgit
@@ -5228,29 +5228,7 @@ END
     my $dgitview = git_rev_parse 'HEAD';
 
     changedir $maindir;
-    # When we no longer need to support squeeze, use --create-reflog
-    # instead of this:
-    ensuredir "$maindir_gitcommon/logs/refs/dgit-intern";
-    my $makelogfh = new IO::File "$maindir_gitcommon/logs/refs/$splitbraincache", '>>'
-      or die $!;
-
-    my $oldcache = git_get_ref "refs/$splitbraincache";
-    if ($oldcache eq $dgitview) {
-	my $tree = cmdoutput qw(git rev-parse), "$dgitview:";
-	# git update-ref doesn't always update, in this case.  *sigh*
-	my $dummy = make_commit_text <<END;
-tree $tree
-parent $dgitview
-author Dgit <dgit\@example.com> 1000000000 +0000
-committer Dgit <dgit\@example.com> 1000000000 +0000
-
-Dummy commit - do not use
-END
-	runcmd @git, qw(update-ref -m), "dgit $our_version - dummy",
-	    "refs/$splitbraincache", $dummy;
-    }
-    runcmd @git, qw(update-ref -m), $cachekey, "refs/$splitbraincache",
-	$dgitview;
+    reflog_cache_insert "refs/$splitbraincache", $cachekey, $dgitview;
 
     changedir "$playground/work";
 
@@ -5753,26 +5731,12 @@ sub quilt_check_splitbrain_cache ($$) {
     push @cachekey, $srcshash->hexdigest();
     $splitbrain_cachekey = "@cachekey";
 
-    my @cmd = (@git, qw(log -g), '--pretty=format:%H %gs',
-	       $splitbraincache);
     printdebug "splitbrain cachekey $splitbrain_cachekey\n";
-    debugcmd "|(probably)",@cmd;
-    my $child = open GC, "-|";  defined $child or die $!;
-    if (!$child) {
-	chdir $maindir or die $!;
-	if (!stat "$maindir_gitcommon/logs/refs/$splitbraincache") {
-	    $! == ENOENT or die $!;
-	    printdebug ">(no reflog)\n";
-	    finish 0;
-	}
-	exec @cmd; die $!;
-    }
-    while (<GC>) {
-	chomp;
-	printdebug ">| ", $_, "\n" if $debuglevel > 1;
-	next unless m/^(\w+) (\S.*\S)$/ && $2 eq $splitbrain_cachekey;
-	    
-	my $cachehit = $1;
+
+    my $cachehit = reflog_cache_lookup
+	"refs/$splitbraincache", $splitbrain_cachekey;
+
+    if ($cachehit) {
 	unpack_playtree_mkwork($headref);
 	my $saved = maybe_split_brain_save $headref, $cachehit, "cache-hit";
 	if ($cachehit ne $headref) {
@@ -5784,8 +5748,6 @@ sub quilt_check_splitbrain_cache ($$) {
 	progress "dgit view: found cached, no changes required";
 	return ($headref, $splitbrain_cachekey);
     }
-    die $! if GC->error;
-    failedcmd unless close GC;
 
     printdebug "splitbrain cache miss\n";
     return (undef, $splitbrain_cachekey);