Started implementing message passing by area. This will be needed for drag & drop messages and will probably be used for large messages instead of sending them through a port. Not yet finished and not enabled. Cleaned up a part of BLooper - this class should probably be cleaned up completely.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@16459 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/app/MessagePrivate4.h

@@ -20,6 +20,10 @@
 #define MAX_ITEM_PREALLOCATION			B_PAGE_SIZE
 
 
+static const int32 kPortMessageCodeDirect = 'pjpp';
+static const int32 kPortMessageCodeByArea = 'pjp2';
+
+
 enum {
 	MESSAGE_FLAG_VALID = 0x0001,
 	MESSAGE_FLAG_REPLY_REQUIRED = 0x0002,
@@ -27,7 +31,7 @@ enum {
 	MESSAGE_FLAG_IS_REPLY = 0x0008,
 	MESSAGE_FLAG_WAS_DELIVERED = 0x0010,
 	MESSAGE_FLAG_HAS_SPECIFIERS = 0x0020,
-	MESSAGE_FLAG_READ_ONLY = 0x0040
+	MESSAGE_FLAG_WAS_DROPPED = 0x0080
 };
 
 
@@ -61,6 +65,7 @@ struct BMessage::message_header {
 
 	int32		target;
 	int32		current_specifier;
+	area_id		shared_area;
 
 	// reply info
 	port_id		reply_port;
@@ -168,6 +173,18 @@ class BMessage::Private {
 			return fMessage->_NativeFlatten(stream, size);
 		}
 
+		status_t
+		FlattenToArea(message_header **header) const
+		{
+			return fMessage->_FlattenToArea(header);
+		}
+
+		status_t
+		Reference(message_header *header)
+		{
+			return fMessage->_Reference(header);
+		}
+
 		status_t
 		SendMessage(port_id port, int32 token, bigtime_t timeout,
 			bool replyRequired, BMessenger &replyTo) const