From 268663da0b2726d94d54f95299ed2c4a0bd7351b Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 11 Aug 2018 21:11:21 +0100
Subject: 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>
---
 Debian/Dgit.pm | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

(limited to 'Debian/Dgit.pm')

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:
-- 
cgit v1.2.3