Get drag and drop working for win aura.

ui/views/widget/desktop_aura/desktop_drop_target_win.cc

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/views/widget/desktop_aura/desktop_drop_target_win.h"
+
+#include "ui/aura/client/drag_drop_client.h"
+#include "ui/aura/client/drag_drop_delegate.h"
+#include "ui/aura/window.h"
+#include "ui/aura/root_window.h"
+#include "ui/base/dragdrop/drag_drop_types.h"
+#include "ui/base/dragdrop/os_exchange_data_provider_win.h"
+#include "ui/base/events/event.h"
+
+using aura::client::DragDropDelegate;
+using ui::OSExchangeData;
+using ui::OSExchangeDataProviderWin;
+
+namespace views {
+
+DesktopDropTargetWin::DesktopDropTargetWin(aura::RootWindow* root_window,
+                                           HWND window)
+    : ui::DropTarget(window),
+      root_window_(root_window),
+      target_window_(NULL) {
+}
+
+DesktopDropTargetWin::~DesktopDropTargetWin() {
+  if (target_window_)
+    target_window_->RemoveObserver(this);
+}
+
+DWORD DesktopDropTargetWin::OnDragEnter(IDataObject* data_object,
+                                        DWORD key_state,
+                                        POINT position,
+                                        DWORD effect) {
+  scoped_ptr<OSExchangeData> data;
+  scoped_ptr<ui::DropTargetEvent> event;
+  DragDropDelegate* delegate;
+  // Translate will call OnDragEntered.
+  Translate(data_object, key_state, position, effect, &data, &event, &delegate);
+  return ui::DragDropTypes::DragOperationToDropEffect(
+      ui::DragDropTypes::DRAG_NONE);
+}
+
+DWORD DesktopDropTargetWin::OnDragOver(IDataObject* data_object,
+                                       DWORD key_state,
+                                       POINT position,
+                                       DWORD effect) {
+  int drag_operation = ui::DragDropTypes::DRAG_NONE;
+  scoped_ptr<OSExchangeData> data;
+  scoped_ptr<ui::DropTargetEvent> event;
+  DragDropDelegate* delegate;
+  Translate(data_object, key_state, position, effect, &data, &event, &delegate);
+  if (delegate)
+    drag_operation = delegate->OnDragUpdated(*event);
+  return ui::DragDropTypes::DragOperationToDropEffect(drag_operation);
+}
+
+void DesktopDropTargetWin::OnDragLeave(IDataObject* data_object) {
+  NotifyDragLeave();
+}
+
+DWORD DesktopDropTargetWin::OnDrop(IDataObject* data_object,
+                                   DWORD key_state,
+                                   POINT position,
+                                   DWORD effect) {
+  int drag_operation = ui::DragDropTypes::DRAG_NONE;
+  scoped_ptr<OSExchangeData> data;
+  scoped_ptr<ui::DropTargetEvent> event;
+  DragDropDelegate* delegate;
+  Translate(data_object, key_state, position, effect, &data, &event, &delegate);
+  if (delegate)
+    drag_operation = delegate->OnPerformDrop(*event);
+  if (target_window_) {
+    target_window_->RemoveObserver(this);
+    target_window_ = NULL;
+  }
+  return ui::DragDropTypes::DragOperationToDropEffect(drag_operation);
+}
+
+void DesktopDropTargetWin::OnWindowDestroyed(aura::Window* window) {
+  DCHECK(window == target_window_);
+  target_window_ = NULL;
+}
+
+void DesktopDropTargetWin::Translate(

[Ben Goodger (Google), 2012/12/07 22:00:26]

GetDragDropDelegateForDragEvent

[jam, 2012/12/07 22:07:29]

I actually had initially called it GetDragDropDelegate, but then I moved in
shared code to create the OSExchangeData and ui::DropTargetEvent so it's not
just returning the delegate. wdyt?

[Ben Goodger (Google), 2012/12/07 22:58:21]

ok whatever. lgtm.

+    IDataObject* data_object,
+    DWORD key_state,
+    POINT position,
+    DWORD effect,
+    scoped_ptr<OSExchangeData>* data,
+    scoped_ptr<ui::DropTargetEvent>* event,
+    DragDropDelegate** delegate) {
+  gfx::Point location(position.x, position.y);
+  gfx::Point root_location = location;
+  root_window_->ConvertPointFromNativeScreen(&root_location);
+  aura::Window* target_window =
+      root_window_->GetEventHandlerForPoint(root_location);
+  bool target_window_changed = false;
+  if (target_window != target_window_) {
+    if (target_window_)
+      NotifyDragLeave();
+    target_window_ = target_window;
+    if (target_window_)
+      target_window_->AddObserver(this);
+    target_window_changed = true;
+  }
+  *delegate = NULL;
+  if (!target_window_)
+    return;
+  *delegate = aura::client::GetDragDropDelegate(target_window_);
+  if (!*delegate)
+    return;
+
+  data->reset(new OSExchangeData(new OSExchangeDataProviderWin(data_object)));
+  location = root_location;
+  aura::Window::ConvertPointToTarget(root_window_, target_window_, &location);
+  event->reset(new ui::DropTargetEvent(
+      *(data->get()),
+      location,
+      root_location,
+      ui::DragDropTypes::DropEffectToDragOperation(effect)));
+  if (target_window_changed)
+    (*delegate)->OnDragEntered(*event->get());
+}
+
+void DesktopDropTargetWin::NotifyDragLeave() {
+  if (!target_window_)
+    return;
+  DragDropDelegate* delegate =
+      aura::client::GetDragDropDelegate(target_window_);
+  if (delegate)
+    delegate->OnDragExited();
+  target_window_->RemoveObserver(this);
+  target_window_ = NULL;
+}
+
+}  // namespace views