Initial version from toddlipcon

File copied from:
https://github.com/toddlipcon/tlipcon-bin/blob/master/git-diff-blame

Author: dmnd

git-diff-blame

@@ -0,0 +1,66 @@
+#!/usr/bin/perl -w
+
+sub parse_hunk_header {
+        my ($line) = @_;
+        my ($o_ofs, $o_cnt, $n_ofs, $n_cnt) =
+            $line =~ /^@@ -(\d+)(?:,(\d+))? \+(\d+)(?:,(\d+))? @@/;
+        $o_cnt = 1 unless defined $o_cnt;
+        $n_cnt = 1 unless defined $n_cnt;
+        return ($o_ofs, $o_cnt, $n_ofs, $n_cnt);
+}
+
+sub get_blame_prefix {
+        my ($line) = @_;
+        $line =~ /^([0-9a-f]+\s+(\S+\s+)?\([^\)]+\))/ or die "bad blame output: $line";
+        return $1;
+}
+
+my ($oldrev, $newrev) = @ARGV;
+open($diff, '-|', 'git', '--no-pager', 'diff', $oldrev, $newrev) or die;
+
+my ($pre, $post);
+my $filename;
+while (<$diff>) {
+        if (m{^diff --git ./(.*) ./\1$}) {
+		close $pre if defined $pre;
+		close $post if defined $post;
+		print;
+                $prefilename = "./" . $1;
+                $postfilename = "./" . $1;
+		$delete = $create = 0;
+        } elsif (m{^new file}) {
+		$create = 1;
+		$prefilename = '/dev/null';
+        } elsif (m{^deleted file}) {
+		$delete = 1;
+		$postfilename = '/dev/null';
+        } elsif (m{^--- $prefilename$}) {
+                # ignore
+		print;
+        } elsif (m{^\+\+\+ $postfilename$}) {
+                # ignore
+		print;
+        } elsif (m{^@@ }) {
+                my ($o_ofs, $o_cnt, $n_ofs, $n_cnt)
+                        = parse_hunk_header($_);
+                my $o_end = $o_ofs + $o_cnt - 1;
+                my $n_end = $n_ofs + $n_cnt - 1;
+		if (!$create) {
+			open($pre, '-|', 'git', 'blame', '-M', "-L$o_ofs,$o_end",
+                             "-l",
+			     $oldrev, '--', $prefilename) or die;
+		}
+		if (!$delete) {
+			open($post, '-|', 'git', 'blame', '-M', "-L$n_ofs,$n_end",
+                             "-l",
+			     $newrev, '--', $postfilename) or die;
+		}
+        } elsif (m{^ }) {
+                print get_blame_prefix(scalar <$pre>), "\t", $_;
+                scalar <$post>; # discard
+        } elsif (m{^\-}) {
+                print get_blame_prefix(scalar <$pre>), "\t", $_;
+        } elsif (m{^\+}) {
+                print get_blame_prefix(scalar <$post>), "\t", $_;
+        } 
+}