From 60690f11257949161344ac1392b365179dc763de Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 16 Jul 2016 17:50:17 +0100
Subject: quilt innards: Break out quilt_check_splitbrain_cache (nfc)

---
 dgit | 134 +++++++++++++++++++++++++++++++++++++------------------------------
 1 file changed, 75 insertions(+), 59 deletions(-)

diff --git a/dgit b/dgit
index 97274e9..835366e 100755
--- a/dgit
+++ b/dgit
@@ -2992,6 +2992,78 @@ END
     close $fakedsc or die $!;
 }
 
+sub quilt_check_splitbrain_cache ($$) {
+    my ($headref, $upstreamversion) = @_;
+    # Checks to see if we are in (potentially) split brain mode.
+    # If so, computes the cache key and looks in the cache.
+    # If split brain is not applicable, returns (undef,0).
+    # Otherwise returns ($cachekey,HIT) where
+    # HIT=0: miss; HIT=1: hit, needs different commit; HIT=2: same commit OK
+
+    quilt_make_fake_dsc($upstreamversion);
+
+    return (undef,0) unless quiltmode_splitbrain();
+
+    my $splitbrain_cachekey;
+    
+    progress
+ "dgit: split brain (separate dgit view) may needed (--quilt=$quilt_mode).";
+    # we look in the reflog of dgit-intern/quilt-cache
+    # we look for an entry whose message is the key for the cache lookup
+    my @cachekey = (qw(dgit), $our_version);
+    push @cachekey, $upstreamversion;
+    push @cachekey, $quilt_mode;
+    push @cachekey, $headref;
+
+    push @cachekey, hashfile('fake.dsc');
+
+    my $srcshash = Digest::SHA->new(256);
+    my %sfs = ( %INC, '$0(dgit)' => $0 );
+    foreach my $sfk (sort keys %sfs) {
+	$srcshash->add($sfk,"  ");
+	$srcshash->add(hashfile($sfs{$sfk}));
+	$srcshash->add("\n");
+    }
+    push @cachekey, $srcshash->hexdigest();
+    $splitbrain_cachekey = "@cachekey";
+
+    my @cmd = (@git, qw(reflog), '--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 '../../..' or die $!;
+	if (!stat ".git/logs/refs/$splitbraincache") {
+	    $! == ENOENT or die $!;
+	    printdebug ">(no reflog)\n";
+	    exit 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;
+	quilt_fixup_mkwork($headref);
+	if ($cachehit ne $headref) {
+	    progress "dgit view: found cached (commit id $cachehit)";
+	    runcmd @git, qw(checkout -q -b dgit-view), $cachehit;
+	    $split_brain = 1;
+	    return ($splitbrain_cachekey, 1);
+	}
+	progress "dgit view: found cached, no changes required";
+	return ($splitbrain_cachekey, 2);
+    }
+    die $! if GC->error;
+    failedcmd unless close GC;
+
+    printdebug "splitbrain cache miss\n";
+    return ($splitbrain_cachekey, 0);
+}
+
 sub quilt_fixup_multipatch ($$$) {
     my ($clogp, $headref, $upstreamversion) = @_;
 
@@ -3066,66 +3138,10 @@ sub quilt_fixup_multipatch ($$$) {
     # afterwards with dpkg-source --before-build.  That lets us save a
     # tree object corresponding to .origs.
 
-    quilt_make_fake_dsc($upstreamversion);
+    my ($splitbrain_cachekey,$cachehit) =
+	quilt_check_splitbrain_cache($headref, $upstreamversion);
 
-    my $splitbrain_cachekey;
-    if (quiltmode_splitbrain()) {
-	progress
- "dgit: split brain (separate dgit view) may needed (--quilt=$quilt_mode).";
-	# we look in the reflog of dgit-intern/quilt-cache
-	# we look for an entry whose message is the key for the cache lookup
-	my @cachekey = (qw(dgit), $our_version);
-	push @cachekey, $upstreamversion;
-	push @cachekey, $quilt_mode;
-	push @cachekey, $headref;
-
-	push @cachekey, hashfile('fake.dsc');
-
-	my $srcshash = Digest::SHA->new(256);
-	my %sfs = ( %INC, '$0(dgit)' => $0 );
-	foreach my $sfk (sort keys %sfs) {
-	    $srcshash->add($sfk,"  ");
-	    $srcshash->add(hashfile($sfs{$sfk}));
-	    $srcshash->add("\n");
-	}
-	push @cachekey, $srcshash->hexdigest();
-	$splitbrain_cachekey = "@cachekey";
-
-	my @cmd = (@git, qw(reflog), '--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 '../../..' or die $!;
-	    if (!stat ".git/logs/refs/$splitbraincache") {
-		$! == ENOENT or die $!;
-		printdebug ">(no reflog)\n";
-		exit 0;
-	    }
-	    exec @cmd; die $!;
-	}
-	while (<GC>) {
-	    chomp;
-	    printdebug ">| ", $_, "\n" if $debuglevel > 1;
-	    next unless m/^(\w+) (\S.*\S)$/ && $2 eq $splitbrain_cachekey;
-	    
-	    my $cachehit = $1;
-	    quilt_fixup_mkwork($headref);
-	    if ($cachehit ne $headref) {
-		progress "dgit view: found cached (commit id $cachehit)";
-		runcmd @git, qw(checkout -q -b dgit-view), $cachehit;
-		$split_brain = 1;
-		return;
-	    }
-	    progress "dgit view: found cached, no changes required";
-	    return;
-	}
-	die $! if GC->error;
-	failedcmd unless close GC;
-
-	printdebug "splitbrain cache miss\n";
-    }
+    return if $splitbrain_cachekey && $cachehit;
 
     runcmd qw(sh -ec),
         'exec dpkg-source --no-check --skip-patches -x fake.dsc >/dev/null';
-- 
cgit v1.2.3