<AWT Dev> [8] Review Request for CR JDK-8020371 [macosx] applets with Drag and Drop fail with IllegalArgumentException

[Petr Pchelko]

Hello, Artem.

I've updated the fix, the new version is here:
http://cr.openjdk.java.net/~pchelko/8020371/webrev.01/

> 1. Are CDropTarget and CDragSourceContextPeer ready to handle the case, when their nativePtr is 0?
	1. CDropTarget: it's absolutely ready, it has only create and release methods which are ready to have a nativePtr=0. 
	In native we create a delegate and set it as the DropTarget to the View. This DropTarget get's notified when NSView see some DnD operation.
	So we cannot and should not set it for applets.

	2. CDragSourceContextPeer - it has only one public method: startDrag which could be called when a DragGestureRecognizer recognizes the Drag. In applets it could never happen,
	so the CDragSourceContextPeer wouldn't event be created. I'be updated it just to make sure we would never get a native crash with 0 viewPtr.

> 2. Lines 110-113 in CDragSourceContextPeer should be better moved to before line 140.
	I've updated the fix.

> 3. It's unclear if CDropTarget and CDragSourceContextPeer should be used for lightweight components at all. How lightweight components are handled on other platforms.?
Not sure about other platforms, but on Mac it works as follows:
	When a DropTarget is set to a lightweight component we set to it's peer and traverse the tree up until we get a non-lightweight peer. And create, update (or don't update) the
	CDropTarget for that peer. The CDragSourceContextPeer is a singleton. When DnD is started we update the trigger in it. The trigger could be any component. To get native support
	we traverse up the tree from the trigger t get a first heavyweight component and use it as a native peer for DnD.

I\m not sure I've answered your question thought.
	
With best regards. Petr.

On Jul 11, 2013, at 4:15 PM, Artem Ananiev wrote:

> Hi, Petr,
> 
> I'm not an expert in this code, so a few questions about the fix:
> 
> 1. Are CDropTarget and CDragSourceContextPeer ready to handle the case, when their nativePtr is 0?
> 
> 2. Lines 110-113 in CDragSourceContextPeer should be better moved to before line 140.
> 
> 3. It's unclear if CDropTarget and CDragSourceContextPeer should be used for lightweight components at all. How lightweight components are handled on other platforms.?
> 
> Thanks,
> 
> Artem
> 
> On 7/11/2013 1:51 PM, Petr Pchelko wrote:
>> Hello, AWT Team.
>> 
>> Please review the fix for the issue:
>> http://bugs.sun.com/view_bug.do?bug_id=8020371
>> (It's recently created, so it might not be visible on bugs.sum.com yet)
>> The fix is available at:
>> http://cr.openjdk.java.net/~pchelko/8020371/webrev/
>> 
>> The problem:
>> We currently do not support DnD in applets on Mac, so IllegalArgumentException was thrown. If you explicitly call component.setDropTarget(new DropTarget()) the applet would fail to start due to this exception.
>> 
>> The solution:
>> The fix removes the exception and silently ignores unsupported DnD initialization.
>> DnD does not start to work, however at least an applet could be started.
>> However, I'm not sure if we should print a warning about unsupported DnD. What do you think?
>> 
>> With best regards. Petr.
>>