src/ui/views/widget/drop_helper.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ui/views/widget/drop_helper.h"
   6
   7 #include "ui/base/dragdrop/drag_drop_types.h"
   8 #include "ui/views/view.h"
   9 #include "ui/views/widget/widget.h"
  10
  11 namespace views {
  12
  13 DropHelper::DropHelper(View* root_view)
  14     : root_view_(root_view),
  15       target_view_(NULL),
  16       deepest_view_(NULL) {
  17 }
  18
  19 DropHelper::~DropHelper() {
  20 }
  21
  22 void DropHelper::ResetTargetViewIfEquals(View* view) {
  23   if (target_view_ == view)
  24     target_view_ = NULL;
  25   if (deepest_view_ == view)
  26     deepest_view_ = NULL;
  27 }
  28
  29 int DropHelper::OnDragOver(const OSExchangeData& data,
  30                            const gfx::Point& root_view_location,
  31                            int drag_operation) {
  32   View* view = CalculateTargetViewImpl(root_view_location, data, true,
  33                                        &deepest_view_);
  34
  35   if (view != target_view_) {
  36     // Target changed notify old drag exited, then new drag entered.
  37     NotifyDragExit();
  38     target_view_ = view;
  39     NotifyDragEntered(data, root_view_location, drag_operation);
  40   }
  41
  42   return NotifyDragOver(data, root_view_location, drag_operation);
  43 }
  44
  45 void DropHelper::OnDragExit() {
  46   NotifyDragExit();
  47   deepest_view_ = target_view_ = NULL;
  48 }
  49
  50 int DropHelper::OnDrop(const OSExchangeData& data,
  51                        const gfx::Point& root_view_location,
  52                        int drag_operation) {
  53   View* drop_view = target_view_;
  54   deepest_view_ = target_view_ = NULL;
  55   if (!drop_view)
  56     return ui::DragDropTypes::DRAG_NONE;
  57
  58   if (drag_operation == ui::DragDropTypes::DRAG_NONE) {
  59     drop_view->OnDragExited();
  60     return ui::DragDropTypes::DRAG_NONE;
  61   }
  62
  63   gfx::Point view_location(root_view_location);
  64   View* root_view = drop_view->GetWidget()->GetRootView();
  65   View::ConvertPointToTarget(root_view, drop_view, &view_location);
  66   ui::DropTargetEvent drop_event(data, view_location, view_location,
  67                                  drag_operation);
  68   return drop_view->OnPerformDrop(drop_event);
  69 }
  70
  71 View* DropHelper::CalculateTargetView(
  72     const gfx::Point& root_view_location,
  73     const OSExchangeData& data,
  74     bool check_can_drop) {
  75   return CalculateTargetViewImpl(root_view_location, data, check_can_drop,
  76                                  NULL);
  77 }
  78
  79 View* DropHelper::CalculateTargetViewImpl(
  80     const gfx::Point& root_view_location,
  81     const OSExchangeData& data,
  82     bool check_can_drop,
  83     View** deepest_view) {
  84   View* view = root_view_->GetEventHandlerForPoint(root_view_location);
  85   if (view == deepest_view_) {
  86     // The view the mouse is over hasn't changed; reuse the target.
  87     return target_view_;
  88   }
  89   if (deepest_view)
  90     *deepest_view = view;
  91   // TODO(sky): for the time being these are separate. Once I port chrome menu
  92   // I can switch to the #else implementation and nuke the OS_WIN
  93   // implementation.
  94 #if defined(OS_WIN)
  95   // View under mouse changed, which means a new view may want the drop.
  96   // Walk the tree, stopping at target_view_ as we know it'll accept the
  97   // drop.
  98   while (view && view != target_view_ &&
  99          (!view->enabled() || !view->CanDrop(data))) {
 100     view = view->parent();
 101   }
 102 #else
 103   int formats = 0;
 104   std::set<OSExchangeData::CustomFormat> custom_formats;
 105   while (view && view != target_view_) {
 106     if (view->enabled() &&
 107         view->GetDropFormats(&formats, &custom_formats) &&
 108         data.HasAnyFormat(formats, custom_formats) &&
 109         (!check_can_drop || view->CanDrop(data))) {
 110       // Found the view.
 111       return view;
 112     }
 113     formats = 0;
 114     custom_formats.clear();
 115     view = view->parent();
 116   }
 117 #endif
 118   return view;
 119 }
 120
 121 void DropHelper::NotifyDragEntered(const OSExchangeData& data,
 122                                    const gfx::Point& root_view_location,
 123                                    int drag_operation) {
 124   if (!target_view_)
 125     return;
 126
 127   gfx::Point target_view_location(root_view_location);
 128   View::ConvertPointToTarget(root_view_, target_view_, &target_view_location);
 129   ui::DropTargetEvent enter_event(data,
 130                                   target_view_location,
 131                                   target_view_location,
 132                                   drag_operation);
 133   target_view_->OnDragEntered(enter_event);
 134 }
 135
 136 int DropHelper::NotifyDragOver(const OSExchangeData& data,
 137                                const gfx::Point& root_view_location,
 138                                int drag_operation) {
 139   if (!target_view_)
 140     return ui::DragDropTypes::DRAG_NONE;
 141
 142   gfx::Point target_view_location(root_view_location);
 143   View::ConvertPointToTarget(root_view_, target_view_, &target_view_location);
 144   ui::DropTargetEvent enter_event(data,
 145                                   target_view_location,
 146                                   target_view_location,
 147                                   drag_operation);
 148   return target_view_->OnDragUpdated(enter_event);
 149 }
 150
 151 void DropHelper::NotifyDragExit() {
 152   if (target_view_)
 153     target_view_->OnDragExited();
 154 }
 155
 156 }  // namespace views