Merge branch 'jc/perl-cat-blob' into maint

perl/Git.pm::cat_blob slurped everything in core only to write it
out to a file descriptor, which was not a very smart thing to do.

* jc/perl-cat-blob:
  Git.pm: fix cat_blob crashes on large files

Author: gitster

perl/Git.pm

@@ -965,20 +965,22 @@ sub cat_blob {
 	my $size = $1;
 
 	my $blob;
-	my $bytesRead = 0;
+	my $bytesLeft = $size;
 
 	while (1) {
-		my $bytesLeft = $size - $bytesRead;
 		last unless $bytesLeft;
 
 		my $bytesToRead = $bytesLeft < 1024 ? $bytesLeft : 1024;
-		my $read = read($in, $blob, $bytesToRead, $bytesRead);
+		my $read = read($in, $blob, $bytesToRead);
 		unless (defined($read)) {
 			$self->_close_cat_blob();
 			throw Error::Simple("in pipe went bad");
 		}
-
-		$bytesRead += $read;
+		unless (print $fh $blob) {
+			$self->_close_cat_blob();
+			throw Error::Simple("couldn't write to passed in filehandle");
+		}
+		$bytesLeft -= $read;
 	}
 
 	# Skip past the trailing newline.
@@ -993,11 +995,6 @@ sub cat_blob {
 		throw Error::Simple("didn't find newline after blob");
 	}
 
-	unless (print $fh $blob) {
-		$self->_close_cat_blob();
-		throw Error::Simple("couldn't write to passed in filehandle");
-	}
-
 	return $size;
 }