Merge pull request #1493 from johnhaddon/displayDriverServerIPv4

DisplayDriverServer : Support IPv4-only environments

Author: ericmehl

Changes

@@ -1,6 +1,11 @@
 10.6.x.x (relative to 10.6.0.1)
 ========
 
+Fixes
+-----
+
+- DisplayDriverServer : Fixed to support IPv4-only environments.
+
 API
 ---
 

src/IECoreImage/DisplayDriverServer.cpp

@@ -189,16 +189,30 @@ class DisplayDriverServer::PrivateData : public RefCounted
 
 		void openPort( DisplayDriverServer::Port portNumber )
 		{
-			m_endpoint = boost::asio::ip::tcp::endpoint( tcp::v6(), portNumber );
-			m_acceptor.open(  m_endpoint.protocol() );
+			boost::system::error_code errorCode;
+			tcp protocol = tcp::v6();
+			m_acceptor.open( protocol, errorCode );
+			if( !errorCode )
+			{
+				// Got IPv6. Allow v4 too.
+				m_acceptor.set_option( boost::asio::ip::v6_only( false ) );
+			}
+			else
+			{
+				// Fall back to IPv4 only.
+				m_acceptor.close();
+				protocol = tcp::v4();
+				m_acceptor.open( protocol );
+			}
+
 #ifdef _MSC_VER
 			m_acceptor.set_option( boost::asio::ip::tcp::acceptor::reuse_address( false ) );
 			typedef boost::asio::detail::socket_option::boolean<BOOST_ASIO_OS_DEF( SOL_SOCKET ), SO_EXCLUSIVEADDRUSE> exclusive_address;
 			m_acceptor.set_option( exclusive_address( true ) );
 #else
 			m_acceptor.set_option( boost::asio::ip::tcp::acceptor::reuse_address( true ) );
 #endif
-			m_acceptor.set_option( boost::asio::ip::v6_only( false ) );
+			m_endpoint = boost::asio::ip::tcp::endpoint( protocol, portNumber );
 			m_acceptor.bind( m_endpoint );
 			m_acceptor.listen();
 		}