First shot at implementing drag&drop for Aura

ui/aura_shell/drag_drop_controller.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/aura_shell/drag_drop_controller.h"
+
+#include "base/message_loop.h"
+#include "ui/aura/client/aura_constants.h"
+#include "ui/aura/client/window_drag_drop_delegate.h"
+#include "ui/aura/desktop.h"
+#include "ui/aura/window.h"
+#include "ui/aura_shell/drag_image_view.h"
+#include "ui/aura_shell/shell.h"
+#include "ui/base/dragdrop/drag_drop_types.h"
+#include "ui/base/dragdrop/os_exchange_data_provider_aura.h"
+#include "ui/gfx/point.h"
+#include "ui/gfx/rect.h"
+#include "views/widget/native_widget_aura.h"
+
+namespace aura_shell {
+namespace internal {
+
+using aura::Desktop;
+
+namespace {
+aura::WindowDragDropDelegate* GetDragDropDelegate(aura::Window* window) {
+  if (!window)
+    return NULL;
+  void* prop = window->GetProperty(aura::kDragDropDelegateKey);
+  if (!prop)
+    return NULL;
+  return static_cast<aura::WindowDragDropDelegate*>(prop);
+}
+
+const gfx::Point kDragDropWidgetOffset(0, 0);
+
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// DragDropController, public:
+
+DragDropController::DragDropController()
+    : aura::EventFilter(Desktop::GetInstance()),
+      drag_image_(NULL),
+      drag_data_(NULL),
+      drag_operation_(0),
+      dragged_window_(NULL),
+      drag_drop_in_progress_(false),
+      should_block_during_drag_drop_(true) {
+  Shell::GetInstance()->AddDesktopEventFilter(this);
+}
+
+DragDropController::~DragDropController() {
+  Shell::GetInstance()->RemoveDesktopEventFilter(this);
+  Cleanup();
+}
+
+void DragDropController::StartDragAndDrop(const ui::OSExchangeData& data,
+                                          int operation) {
+  DCHECK(!drag_drop_in_progress_);
+  aura::Window* capture_window = Desktop::GetInstance()->capture_window();
+  if (capture_window)
+    Desktop::GetInstance()->ReleaseCapture(capture_window);
+  drag_drop_in_progress_ = true;
+
+  drag_data_ = &data;
+  drag_operation_ = operation;
+  gfx::Point location = Desktop::GetInstance()->last_mouse_location();
+  const ui::OSExchangeDataProviderAura& provider =
+      static_cast<const ui::OSExchangeDataProviderAura&>(data.provider());
+
+  drag_image_.reset(new DragImageView);
+  drag_image_->SetImage(provider.drag_image());
+  drag_image_->SetScreenBounds(gfx::Rect(location.Add(kDragDropWidgetOffset),
+      drag_image_->GetPreferredSize()));
+  drag_image_->SetWidgetVisible(true);
+
+  dragged_window_ = Desktop::GetInstance()->GetEventHandlerForPoint(location);
+
+  if (should_block_during_drag_drop_) {
+    MessageLoopForUI::current()->RunWithDispatcher(
+        Desktop::GetInstance()->GetDispatcher());
+  }
+}
+
+void DragDropController::DragUpdate(aura::Window* target,
+                                    const aura::MouseEvent& event) {
+  aura::WindowDragDropDelegate* delegate = NULL;
+  if (target != dragged_window_) {
+    if ((delegate = GetDragDropDelegate(dragged_window_)))
+      delegate->OnDragExited();
+    dragged_window_ = target;
+    if ((delegate = GetDragDropDelegate(dragged_window_))) {
+      aura::DropTargetEvent e(*drag_data_, event.location(), drag_operation_);
+      if (delegate->CanDrop(e))
+        delegate->OnDragEntered(e);
+    }
+  } else {
+    if ((delegate = GetDragDropDelegate(dragged_window_))) {
+      aura::DropTargetEvent e(*drag_data_, event.location(), drag_operation_);
+      delegate->OnDragUpdated(e);
+      // TODO(varunjain): uncomment the following lines when cursor issue with
+      // X for tests is fixed.
+      // gfx::NativeCursor cursor = (op == ui::DragDropTypes::DRAG_NONE)?
+      //     aura::kCursorMove : aura::kCursorHand;
+      // Desktop::GetInstance()->SetCursor(cursor);
+    }
+  }
+
+  DCHECK(drag_image_.get());
+  if (drag_image_->IsVisible()) {
+    drag_image_->SetScreenPosition(Desktop::GetInstance()->
+        last_mouse_location().Add(kDragDropWidgetOffset));
+  }
+}
+
+void DragDropController::Drop(aura::Window* target,
+                              const aura::MouseEvent& event) {
+  aura::WindowDragDropDelegate* delegate = NULL;
+  DCHECK(target == dragged_window_);
+  if ((delegate = GetDragDropDelegate(dragged_window_))) {
+    aura::DropTargetEvent e(*drag_data_, event.location(), drag_operation_);
+    if (delegate->CanDrop(e))
+      delegate->OnPerformDrop(e);
+    // TODO(varunjain): else Do drag widget flying back animation
+  }
+
+  Cleanup();
+  if (should_block_during_drag_drop_)
+    MessageLoop::current()->Quit();
+}
+
+void DragDropController::DragCancel() {
+  // TODO(varunjain): Do drag widget flying back animation
+  Cleanup();
+  if (should_block_during_drag_drop_)
+    MessageLoop::current()->Quit();
+}
+
+bool DragDropController::PreHandleKeyEvent(aura::Window* target,
+                                           aura::KeyEvent* event) {
+  return false;
+}
+
+bool DragDropController::PreHandleMouseEvent(aura::Window* target,
+                                             aura::MouseEvent* event) {
+  if (!drag_drop_in_progress_)
+    return false;
+  switch (event->type()) {
+    case ui::ET_MOUSE_DRAGGED:
+      DragUpdate(target, *event);
+      break;
+    case ui::ET_MOUSE_RELEASED:
+      Drop(target, *event);
+      break;
+    case ui::ET_MOUSE_EXITED:
+      DragCancel();
+      break;
+    default:
+      NOTREACHED();
+      break;
+  }
+  return true;
+}
+
+ui::TouchStatus DragDropController::PreHandleTouchEvent(
+    aura::Window* target,
+    aura::TouchEvent* event) {
+  return ui::TOUCH_STATUS_UNKNOWN;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// DragDropController, private:
+
+void DragDropController::Cleanup() {
+  drag_image_.reset();
+  drag_data_ = NULL;
+  drag_operation_ = 0;
+  drag_drop_in_progress_ = false;
+}
+
+}  // namespace internal
+}  // namespace aura_shell