Fix stream_backend_file in the perl bindings

stream_backend_file seems to be broken in 24-fixes and master in the following
ways:
1. When sending the FileTransfer command, it doesn't include all required
parameters causing the backend to respond with "malformed_filetransfer_command"
2. The length of the file to be streamed is not parsed correctly when >
2147483647, which results in corrupt or zero length files being written to
disk

This patch fixes these issues.  Patch applies cleanly to 24-fixes and master

The file length fix was tested against files of lengths 2012338647
(regression), 2500703244 (requires conversion to unsigned to be interpreted
correctly), and 31219659384 (test longlong)

Fixes #9837

Signed-off-by: Gavin Hurlbut <ghurlbut@mythtv.org>

mythtv/bindings/perl/MythTV.pm

@@ -23,6 +23,7 @@ package MythTV;
     use DBI;
     use HTTP::Request;
     use LWP::UserAgent;
+    use Math::BigInt;
 
 # Load the UPNP libraries if we have them, but die nicely if we don't.
     BEGIN {
@@ -592,8 +593,8 @@ EOF
         my $sock = $self->new_backend_socket($host,
                                              $port,
                                              join($MythTV::BACKEND_SEP,
-                                                  'ANN FileTransfer '.hostname,
-                                                  $basename));
+                                                  'ANN FileTransfer '.hostname.
+                                                  ' 0 1 2000', $basename, '...'));
         my @recs = split($MythTV::BACKEND_SEP_rx,
                          $sock->read_data());
     # Error?
@@ -612,7 +613,8 @@ EOF
             $csock->read_data();
         }
     # Transfer the data.
-        my $total = $recs[3];
+        # File size is longlong but is sent as 2 signed ints
+        my $total = $self->decodeLongLong($recs[2], $recs[3]);
         while ($sock && $total > 0) {
         # Attempt to read in 2M chunks, or the remaining total, whichever is
         # smaller.
@@ -649,6 +651,27 @@ EOF
     # Return
         return 2;
     }
+ # Analogous to decodeLongLong in decodeencode.cpp
+    sub decodeLongLong {
+        my $self = shift;
+        my $first = shift;
+        my $longlong = Math::BigInt->bzero();
+        if($first) { # 1st unsigned int is most significant
+           my $maxInt = Math::BigInt->new('4294967296');
+           my $shifted = $self->signedToUnsignedInt($first) * $maxInt;
+           $longlong += $shifted;
+        }
+        # add the 2nd unsigned int
+        $longlong += $self->signedToUnsignedInt(shift);
+        return $longlong;
+    }
+
+    sub signedToUnsignedInt {
+        my $self = shift;
+        $b = pack( "l", shift);
+        my @array = unpack( "L", $b );
+        return Math::BigInt->new(@array);
+    }
 
 # Check the MythProto version between the backend and this script
     sub check_proto_version {