From 8165fa3936801e2de84bbc9b7a13b2e6e27c8abd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stephan=20A=C3=9Fmus?= <superstippi@gmx.de>
Date: Mon, 17 Apr 2006 20:42:22 +0000
Subject: [PATCH] * fix bug 414 by Sync()ing in UpdateIfNeeded() to make   sure
 all messages that could trigger an update have   actually arrived at the
 server * small clean ups here and there, some clarifications in   comments *
 check for the return value of Lock() in DisableUpdates()   and
 EnableUpdates()

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@17158 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 src/kits/interface/Window.cpp | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/src/kits/interface/Window.cpp b/src/kits/interface/Window.cpp
index 35d55eb538..affd35d1f5 100644
--- a/src/kits/interface/Window.cpp
+++ b/src/kits/interface/Window.cpp
@@ -536,20 +536,22 @@ BWindow::Sync() const
 void
 BWindow::DisableUpdates()
 {
-	Lock();
-	fLink->StartMessage(AS_DISABLE_UPDATES);
-	fLink->Flush();
-	Unlock();
+	if (Lock()) {
+		fLink->StartMessage(AS_DISABLE_UPDATES);
+		fLink->Flush();
+		Unlock();
+	}
 }
 
 
 void
 BWindow::EnableUpdates()
 {
-	Lock();
-	fLink->StartMessage(AS_ENABLE_UPDATES);
-	fLink->Flush();
-	Unlock();
+	if (Lock()) {
+		fLink->StartMessage(AS_ENABLE_UPDATES);
+		fLink->Flush();
+		Unlock();
+	}
 }
 
 
@@ -968,6 +970,7 @@ FrameMoved(origin);
 
 		case _UPDATE_:
 		{
+//bigtime_t now = system_time();
 			STRACE(("info:BWindow handling _UPDATE_.\n"));
 			BRect updateRect;
 
@@ -1035,6 +1038,7 @@ FrameMoved(origin);
 			fLink->Flush();
 			fInTransaction = false;
 
+//printf("BWindow(%s) - UPDATE took %lld usecs\n", Title(), system_time() - now);
 			break;
 		}
 
@@ -1410,11 +1414,14 @@ BWindow::NeedsUpdate() const
 void
 BWindow::UpdateIfNeeded()
 {
-	// TODO: What about locking?!?
-	// works only from this thread
+	// works only from the window thread
 	if (find_thread(NULL) != Thread())
 		return;
 
+	// make sure all requests that would cause an update have
+	// arrived at the server
+	Sync();
+
 	// Since we're blocking the event loop, we need to retrieve 
 	// all messages that are pending on the port.
 	_DequeueAll();
@@ -1423,7 +1430,7 @@ BWindow::UpdateIfNeeded()
 	queue->Lock();
 
 	// First process and remove any _UPDATE_ message in the queue
-	// According to Adi, there can only be one at a time
+	// With the current design, there can only be one at a time
 
 	BMessage *msg;
 	for (int32 i = 0; (msg = queue->FindMessage(i)) != NULL; i++) {
@@ -1435,6 +1442,8 @@ BWindow::UpdateIfNeeded()
 			queue->RemoveMessage(msg);
 			delete msg;
 			break;
+			// NOTE: "i" would have to be decreased if there were
+			// multiple _UPDATE_ messages and we would not break!
 		}
 	}