BAppServerLink is now using BApplication::fServerTo/From for its messaging.

Added LinkMsgReader::NeedsReply() method.
Completely redone ServerApp messaging: no more "replyport" from BAppServerLink; instead,
the registered client reply port is used. Fixed some more weak messaging stuff.
ServerApp now recognizes if an unknown message needs a reply, and sends it - for example,
the "Screen" preferences app no longer hangs, but crashes on start :)
Made LinkMsgReader::Read() virtual again, since it's needed by RAMLinkMsgReader.cpp.
Renamed BPortLink::GetNextReply() to GetNextMessage().
Some more cleanup.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@13004 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/kits/app/LinkMsgReader.cpp

@@ -102,6 +102,17 @@ LinkMsgReader::GetNextMessage(int32 &code, bigtime_t timeout)
 }
 
 
+bool
+LinkMsgReader::NeedsReply() const
+{
+	if (fReplySize == 0)
+		return false;
+
+	message_header *header = (message_header *)(fRecvBuffer + fRecvStart);
+	return (header->flags & kNeedsReply) != 0;
+}
+
+
 void
 LinkMsgReader::ResetBuffer()
 {