From d3e8d3f2711c3b2b2bbda4c6c89cfaa28cf68e2e Mon Sep 17 00:00:00 2001
From: Stefan Csomor <csomor@advancedconcepts.ch>
Date: Mon, 16 Jul 2018 19:42:35 +0200
Subject: [PATCH] Support or disable "insert" for drag/drop wxDataViewCtrl on
 OSX

see #18167
---
 include/wx/dataview.h     |  8 +++++++-
 src/common/datavcmn.cpp   |  1 +
 src/osx/cocoa/dataview.mm | 26 ++++++++++++++++++++------
 3 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/include/wx/dataview.h b/include/wx/dataview.h
index 58b0fdafe4..573caf5227 100644
--- a/include/wx/dataview.h
+++ b/include/wx/dataview.h
@@ -846,7 +846,8 @@ public:
         m_dataBuffer(event.m_dataBuffer),
         m_dataSize(event.m_dataSize),
         m_dragFlags(event.m_dragFlags),
-        m_dropEffect(event.m_dropEffect)
+        m_dropEffect(event.m_dropEffect),
+        m_proposedDropIndex(event.m_proposedDropIndex)
 #endif
         { }
 
@@ -889,6 +890,10 @@ public:
     int GetDragFlags() const { return m_dragFlags; }
     void SetDropEffect( wxDragResult effect ) { m_dropEffect = effect; }
     wxDragResult GetDropEffect() const { return m_dropEffect; }
+    // for plaforms (currently only OSX) that support Drag/Drop insertion of items,
+	// this is the proposed child index for the insertion
+	void SetProposedDropIndex(int index) { m_proposedDropIndex = index; }
+	int GetProposedDropIndex() const { return m_proposedDropIndex;}
 #endif // wxUSE_DRAG_AND_DROP
 
     virtual wxEvent *Clone() const wxOVERRIDE { return new wxDataViewEvent(*this); }
@@ -928,6 +933,7 @@ protected:
 
     int                 m_dragFlags;
     wxDragResult        m_dropEffect;
+    int                 m_proposedDropIndex;
 #endif // wxUSE_DRAG_AND_DROP
 
 private:
diff --git a/src/common/datavcmn.cpp b/src/common/datavcmn.cpp
index 1c3609261e..fd68880243 100644
--- a/src/common/datavcmn.cpp
+++ b/src/common/datavcmn.cpp
@@ -1683,6 +1683,7 @@ void wxDataViewEvent::Init(wxDataViewCtrlBase* dvc,
     m_dataSize = 0;
     m_dragFlags = 0;
     m_dropEffect = wxDragNone;
+    m_proposedDropIndex = -1;
 #endif // wxUSE_DRAG_AND_DROP
 
     SetEventObject(dvc);
diff --git a/src/osx/cocoa/dataview.mm b/src/osx/cocoa/dataview.mm
index 82c02cc8a7..a2b20c00a0 100644
--- a/src/osx/cocoa/dataview.mm
+++ b/src/osx/cocoa/dataview.mm
@@ -539,9 +539,8 @@ outlineView:(NSOutlineView*)outlineView
     item:(id)item childIndex:(NSInteger)index
 {
     wxUnusedVar(outlineView);
-    wxUnusedVar(index);
     
-    return [self setupAndCallDataViewEvents:wxEVT_DATAVIEW_ITEM_DROP dropInfo:info item:item] != NSDragOperationNone;
+    return [self setupAndCallDataViewEvents:wxEVT_DATAVIEW_ITEM_DROP dropInfo:info item:item proposedChildIndex:index] != NSDragOperationNone;
 }
 
 -(id) outlineView:(NSOutlineView*)outlineView
@@ -680,10 +679,11 @@ outlineView:(NSOutlineView*)outlineView
     wxUnusedVar(outlineView);
     wxUnusedVar(index);
 
-    return [self setupAndCallDataViewEvents:wxEVT_DATAVIEW_ITEM_DROP_POSSIBLE dropInfo:info item:item];
+    return [self setupAndCallDataViewEvents:wxEVT_DATAVIEW_ITEM_DROP_POSSIBLE dropInfo:info item:item proposedChildIndex:index];
 }
 
 -(NSDragOperation) callDataViewEvents:(wxEventType)eventType dataObjects:(wxDataObjectComposite*)dataObjects item:(id)item
+                   proposedChildIndex:(NSInteger)index
 {
     NSDragOperation dragOperation = NSDragOperationNone;
     wxDataViewCtrl* const dvc(implementation->GetDataViewCtrl());
@@ -693,7 +693,20 @@ outlineView:(NSOutlineView*)outlineView
         // copy data into data object:
         event.SetDataObject(dataObjects);
         event.SetDataFormat(implementation->GetDnDDataFormat(dataObjects));
-        event.SetDropEffect(wxDragCopy);
+        event.SetProposedDropIndex(index);
+        if (index == -1)
+        {
+            event.SetDropEffect(wxDragCopy);
+        }
+        else
+        {
+            //if index is not -1, we're going to set the default
+            //for the drop effect to None to be compatible with
+            //the other wxPlatforms that don't support it.  In the
+            //user code for for the event, they can set this to
+            //copy/move or similar to support it.
+            event.SetDropEffect(wxDragNone);
+        }
         wxDataFormatId formatId = event.GetDataFormat().GetType();
         wxMemoryBuffer buffer;
         
@@ -745,6 +758,7 @@ outlineView:(NSOutlineView*)outlineView
 }
 
 -(NSDragOperation) setupAndCallDataViewEvents:(wxEventType)eventType dropInfo:(id<NSDraggingInfo>)info item:(id)item
+                           proposedChildIndex:(NSInteger)index
 {
     NSArray* supportedTypes(
                             [NSArray arrayWithObjects:DataViewPboardType,NSStringPboardType,nil]
@@ -774,7 +788,7 @@ outlineView:(NSOutlineView*)outlineView
         {
             wxDataObjectComposite* dataObjects(implementation->GetDnDDataObjects((NSData*)[dataArray objectAtIndex:indexDraggedItem]));
             
-            dragOperation = [self callDataViewEvents:eventType dataObjects:dataObjects item:item];
+            dragOperation = [self callDataViewEvents:eventType dataObjects:dataObjects item:item proposedChildIndex:index];
             
             if ( dragOperation != NSDragOperationNone )
                 ++indexDraggedItem;
@@ -806,7 +820,7 @@ outlineView:(NSOutlineView*)outlineView
             delete textDataObject;
         // send event if data could be copied:
         
-        dragOperation = [self callDataViewEvents:eventType dataObjects:dataObjects item:item];
+        dragOperation = [self callDataViewEvents:eventType dataObjects:dataObjects item:item proposedChildIndex:index];
 
         // clean up:
         ::CFRelease(osxData);