Bug 549661 - [Win32][DND] FileTransfer can not drop on Portable Device

First problem: dropping on Portable Device does not like the fake PIDLs
which were used before.
Second problem: dropping on Portable Device query for the data after the
drag and drop operation is finished.

Change-Id: Ic5f17e12c070759fb957d5010cd8cec5165fc8ff
Signed-off-by: Paul Pazderski <paul-eclipse@ppazderski.de>

2 files changed, 34 insertions, 4 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT Drag and Drop/win32/org/eclipse/swt/dnd/DragSource.java b/bundles/org.eclipse.swt/Eclipse SWT Drag and Drop/win32/org/eclipse/swt/dnd/DragSource.java
index c4c4e09894..3615995c1a 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT Drag and Drop/win32/org/eclipse/swt/dnd/DragSource.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT Drag and Drop/win32/org/eclipse/swt/dnd/DragSource.java
@@ -391,6 +391,31 @@ private void drag(Event dragEvent) {
 		}
 	}
 
+	/*
+	 * Bug 549643: a proper drag&drop operation is finished when the DoDragDrop loop/function returns.
+	 * Unfortunately the Windows Explorer is ignoring this fact while showing a Portable Device
+	 * (e.g. Smartphone attached through MTP). I.e. dropping a file on Windows Explorer in this
+	 * situation will query the iDataObject at least once for its data _after_ DoDragDrop finished.
+	 * Revoking this getData request will fail the drop.
+	 *
+	 * This behavior can succeeds because most applications store the actual data to transfer in
+	 * the IDataObject and since its lifetime is managed through ref counting it can return the data
+	 * even after the drag&drop finished. In SWT the data to transfer is not stored in the IDataObject
+	 * but instead obtained on demand through a DND.DragSetData event. Additional some clients release
+	 * the data to drag in the DragEnd event and therefore do not like to get such events after DragEnd.
+	 *
+	 * That's why the next few lines exist. In case the DropTarget has not yet released the IDataObject
+	 * (which is the case for the faulty Windows Explorer described above) we delay the DragEnd event in
+	 * case an additional DragSetData is triggered. Since the DropTarget can be any (faulty or malicious)
+	 * application maybe never releasing the object wait is combined with a tight timeout.
+	 */
+	final long start = System.currentTimeMillis();
+	while (refCount > 0 && System.currentTimeMillis() - start < 1000) {
+		if (!display.readAndDispatch()) {
+			try { Thread.sleep(10); }
+			catch (InterruptedException e) { break; }
+		}
+	}
 	disposeCOMInterfaces();
 
 	event = new DNDEvent();
diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/com_custom.cpp b/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/com_custom.cpp
index e4509e4c94..791d8df1be 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/com_custom.cpp
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/com_custom.cpp
@@ -71,13 +71,18 @@ private:
 };
 
 /*
- * An extended version of SHParseDisplayName which ignores the attribute query part
- * and use bind context to support creation of simple PIDLs for non existing paths.
+ * An extended version of SHParseDisplayName which use bind context to support
+ * creation of simple PIDLs in case the normal PIDL creation failed.
+ * (most likley due to non existing file/directory)
  */
 extern "C" HRESULT PathToPIDL(PCWSTR pszName, PIDLIST_ABSOLUTE *ppidl)
 {
 	if (!ppidl) return E_FAIL;
 	*ppidl = nullptr;
+	
+	SFGAOF sfgao = 0;
+	HRESULT hr = SHParseDisplayName(pszName, nullptr, ppidl, sfgao, &sfgao);
+	if (hr == S_OK) return hr;
 
 	IFileSystemBindData *pfsbd = new CFileSysBindData();
 	if (!pfsbd) return E_OUTOFMEMORY;
@@ -87,7 +92,7 @@ extern "C" HRESULT PathToPIDL(PCWSTR pszName, PIDLIST_ABSOLUTE *ppidl)
 
 	IBindCtx* pbc;
 
-	HRESULT hr = CreateBindCtx(0, &pbc);
+	hr = CreateBindCtx(0, &pbc);
 	if (hr == S_OK)
 	{
 		BIND_OPTS bo = { sizeof(bo), 0, STGM_CREATE, 0 };
@@ -97,7 +102,7 @@ extern "C" HRESULT PathToPIDL(PCWSTR pszName, PIDLIST_ABSOLUTE *ppidl)
 			hr = pbc->RegisterObjectParam(STR_FILE_SYS_BIND_DATA, pfsbd);
 			if (hr == S_OK)
 			{
-				SFGAOF sfgao = 0;
+				sfgao = 0;
 				hr = SHParseDisplayName(pszName, pbc, ppidl, sfgao, &sfgao);
 			}
 		}