ui/accessibility/platform/ax_platform_node_win.h

   1 // Copyright 2015 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 #ifndef UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_WIN_H_
   6 #define UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_WIN_H_
   7
   8 #include <atlbase.h>
   9 #include <atlcom.h>
  10 #include <oleacc.h>
  11
  12 #include "third_party/iaccessible2/ia2_api_all.h"
  13 #include "ui/accessibility/platform/ax_platform_node_base.h"
  14
  15 namespace ui {
  16
  17 class __declspec(uuid("26f5641a-246d-457b-a96d-07f3fae6acf2"))
  18 AXPlatformNodeWin
  19 : public CComObjectRootEx<CComMultiThreadModel>,
  20     public IDispatchImpl<IAccessible2_2, &IID_IAccessible2,
  21                          &LIBID_IAccessible2Lib>,
  22     public IAccessibleText,
  23     public IServiceProvider,
  24     public AXPlatformNodeBase {
  25  public:
  26   BEGIN_COM_MAP(AXPlatformNodeWin)
  27     COM_INTERFACE_ENTRY2(IDispatch, IAccessible2_2)
  28     COM_INTERFACE_ENTRY(AXPlatformNodeWin)
  29     COM_INTERFACE_ENTRY(IAccessible)
  30     COM_INTERFACE_ENTRY(IAccessible2)
  31     COM_INTERFACE_ENTRY(IAccessible2_2)
  32     COM_INTERFACE_ENTRY(IAccessibleText)
  33     COM_INTERFACE_ENTRY(IServiceProvider)
  34   END_COM_MAP()
  35
  36   ~AXPlatformNodeWin() override;
  37
  38   // AXPlatformNode overrides.
  39   void Destroy() override;
  40   gfx::NativeViewAccessible GetNativeViewAccessible() override;
  41   void NotifyAccessibilityEvent(ui::AXEvent event_type) override;
  42
  43   // AXPlatformNodeBase overrides.
  44   int GetIndexInParent() override;
  45
  46   //
  47   // IAccessible methods.
  48   //
  49
  50   // Retrieves the child element or child object at a given point on the screen.
  51   STDMETHODIMP accHitTest(LONG x_left, LONG y_top, VARIANT* child) override;
  52
  53   // Performs the object's default action.
  54   STDMETHODIMP accDoDefaultAction(VARIANT var_id) override;
  55
  56   // Retrieves the specified object's current screen location.
  57   STDMETHODIMP accLocation(LONG* x_left,
  58                            LONG* y_top,
  59                            LONG* width,
  60                            LONG* height,
  61                            VARIANT var_id) override;
  62
  63   // Traverses to another UI element and retrieves the object.
  64   STDMETHODIMP accNavigate(LONG nav_dir, VARIANT start, VARIANT* end) override;
  65
  66   // Retrieves an IDispatch interface pointer for the specified child.
  67   STDMETHODIMP get_accChild(VARIANT var_child, IDispatch** disp_child) override;
  68
  69   // Retrieves the number of accessible children.
  70   STDMETHODIMP get_accChildCount(LONG* child_count) override;
  71
  72   // Retrieves a string that describes the object's default action.
  73   STDMETHODIMP get_accDefaultAction(VARIANT var_id,
  74                                     BSTR* default_action) override;
  75
  76   // Retrieves the tooltip description.
  77   STDMETHODIMP get_accDescription(VARIANT var_id, BSTR* desc) override;
  78
  79   // Retrieves the object that has the keyboard focus.
  80   STDMETHODIMP get_accFocus(VARIANT* focus_child) override;
  81
  82   // Retrieves the specified object's shortcut.
  83   STDMETHODIMP get_accKeyboardShortcut(VARIANT var_id,
  84                                        BSTR* access_key) override;
  85
  86   // Retrieves the name of the specified object.
  87   STDMETHODIMP get_accName(VARIANT var_id, BSTR* name) override;
  88
  89   // Retrieves the IDispatch interface of the object's parent.
  90   STDMETHODIMP get_accParent(IDispatch** disp_parent) override;
  91
  92   // Retrieves information describing the role of the specified object.
  93   STDMETHODIMP get_accRole(VARIANT var_id, VARIANT* role) override;
  94
  95   // Retrieves the current state of the specified object.
  96   STDMETHODIMP get_accState(VARIANT var_id, VARIANT* state) override;
  97
  98   // Gets the help string for the specified object.
  99   STDMETHODIMP get_accHelp(VARIANT var_id, BSTR* help) override;
 100
 101   // Retrieve or set the string value associated with the specified object.
 102   // Setting the value is not typically used by screen readers, but it's
 103   // used frequently by automation software.
 104   STDMETHODIMP get_accValue(VARIANT var_id, BSTR* value) override;
 105   STDMETHODIMP put_accValue(VARIANT var_id, BSTR new_value) override;
 106
 107   // IAccessible methods not implemented.
 108   STDMETHODIMP get_accSelection(VARIANT* selected) override;
 109   STDMETHODIMP accSelect(LONG flags_sel, VARIANT var_id) override;
 110   STDMETHODIMP get_accHelpTopic(BSTR* help_file,
 111                                 VARIANT var_id,
 112                                 LONG* topic_id) override;
 113   STDMETHODIMP put_accName(VARIANT var_id, BSTR put_name) override;
 114
 115   //
 116   // IAccessible2 methods.
 117   //
 118
 119   STDMETHODIMP role(LONG* role) override;
 120
 121   STDMETHODIMP get_states(AccessibleStates* states) override;
 122
 123   STDMETHODIMP get_uniqueID(LONG* unique_id) override;
 124
 125   STDMETHODIMP get_windowHandle(HWND* window_handle) override;
 126
 127   STDMETHODIMP get_relationTargetsOfType(BSTR type,
 128                                          long max_targets,
 129                                          IUnknown*** targets,
 130                                          long* n_targets) override;
 131
 132   STDMETHODIMP get_attributes(BSTR* attributes) override;
 133
 134   STDMETHODIMP get_indexInParent(LONG* index_in_parent) override;
 135
 136   //
 137   // IAccessible2 methods not implemented.
 138   //
 139
 140   STDMETHODIMP get_attribute(BSTR name, VARIANT* attribute) override {
 141     return E_NOTIMPL;
 142   }
 143   STDMETHODIMP get_extendedRole(BSTR* extended_role) override {
 144     return E_NOTIMPL;
 145   }
 146   STDMETHODIMP get_nRelations(LONG* n_relations) override { return E_NOTIMPL; }
 147   STDMETHODIMP get_relation(LONG relation_index,
 148                             IAccessibleRelation** relation) override {
 149     return E_NOTIMPL;
 150   }
 151   STDMETHODIMP get_relations(LONG max_relations,
 152                              IAccessibleRelation** relations,
 153                              LONG* n_relations) override {
 154     return E_NOTIMPL;
 155   }
 156   STDMETHODIMP scrollTo(enum IA2ScrollType scroll_type) override {
 157     return E_NOTIMPL;
 158   }
 159   STDMETHODIMP scrollToPoint(enum IA2CoordinateType coordinate_type,
 160                              LONG x,
 161                              LONG y) override {
 162     return E_NOTIMPL;
 163   }
 164   STDMETHODIMP get_groupPosition(LONG* group_level,
 165                                  LONG* similar_items_in_group,
 166                                  LONG* position_in_group) override {
 167     return E_NOTIMPL;
 168   }
 169   STDMETHODIMP get_localizedExtendedRole(
 170       BSTR* localized_extended_role) override {
 171     return E_NOTIMPL;
 172   }
 173   STDMETHODIMP get_nExtendedStates(LONG* n_extended_states) override {
 174     return E_NOTIMPL;
 175   }
 176   STDMETHODIMP get_extendedStates(LONG max_extended_states,
 177                                   BSTR** extended_states,
 178                                   LONG* n_extended_states) override {
 179     return E_NOTIMPL;
 180   }
 181   STDMETHODIMP get_localizedExtendedStates(
 182       LONG max_localized_extended_states,
 183       BSTR** localized_extended_states,
 184       LONG* n_localized_extended_states) override {
 185     return E_NOTIMPL;
 186   }
 187   STDMETHODIMP get_locale(IA2Locale* locale) override { return E_NOTIMPL; }
 188   STDMETHODIMP get_accessibleWithCaret(IUnknown** accessible,
 189                                        long* caret_offset) override {
 190     return E_NOTIMPL;
 191   }
 192
 193   //
 194   // IAccessibleText methods.
 195   //
 196
 197   STDMETHODIMP get_nCharacters(LONG* n_characters) override;
 198
 199   STDMETHODIMP get_caretOffset(LONG* offset) override;
 200
 201   STDMETHODIMP get_nSelections(LONG* n_selections) override;
 202
 203   STDMETHODIMP get_selection(LONG selection_index,
 204                              LONG* start_offset,
 205                              LONG* end_offset) override;
 206
 207   STDMETHODIMP get_text(LONG start_offset,
 208                         LONG end_offset,
 209                         BSTR* text) override;
 210
 211   STDMETHODIMP get_textAtOffset(LONG offset,
 212                                 enum IA2TextBoundaryType boundary_type,
 213                                 LONG* start_offset,
 214                                 LONG* end_offset,
 215                                 BSTR* text) override;
 216
 217   STDMETHODIMP get_textBeforeOffset(LONG offset,
 218                                     enum IA2TextBoundaryType boundary_type,
 219                                     LONG* start_offset,
 220                                     LONG* end_offset,
 221                                     BSTR* text) override;
 222
 223   STDMETHODIMP get_textAfterOffset(LONG offset,
 224                                    enum IA2TextBoundaryType boundary_type,
 225                                    LONG* start_offset,
 226                                    LONG* end_offset,
 227                                    BSTR* text) override;
 228
 229   STDMETHODIMP get_offsetAtPoint(LONG x,
 230                                  LONG y,
 231                                  enum IA2CoordinateType coord_type,
 232                                  LONG* offset) override;
 233
 234   //
 235   // IAccessibleText methods not implemented.
 236   //
 237
 238   STDMETHODIMP get_newText(IA2TextSegment* new_text) override {
 239     return E_NOTIMPL;
 240   }
 241   STDMETHODIMP get_oldText(IA2TextSegment* old_text) override {
 242     return E_NOTIMPL;
 243   }
 244   STDMETHODIMP addSelection(LONG start_offset, LONG end_offset) override {
 245     return E_NOTIMPL;
 246   }
 247   STDMETHODIMP get_attributes(LONG offset,
 248                               LONG* start_offset,
 249                               LONG* end_offset,
 250                               BSTR* text_attributes) override {
 251     return E_NOTIMPL;
 252   }
 253   STDMETHODIMP get_characterExtents(LONG offset,
 254                                     enum IA2CoordinateType coord_type,
 255                                     LONG* x,
 256                                     LONG* y,
 257                                     LONG* width,
 258                                     LONG* height) override {
 259     return E_NOTIMPL;
 260   }
 261   STDMETHODIMP removeSelection(LONG selection_index) override {
 262     return E_NOTIMPL;
 263   }
 264   STDMETHODIMP setCaretOffset(LONG offset) override { return E_NOTIMPL; }
 265   STDMETHODIMP setSelection(LONG selection_index,
 266                             LONG start_offset,
 267                             LONG end_offset) override {
 268     return E_NOTIMPL;
 269   }
 270   STDMETHODIMP scrollSubstringTo(LONG start_index,
 271                                  LONG end_index,
 272                                  enum IA2ScrollType scroll_type) override {
 273     return E_NOTIMPL;
 274   }
 275   STDMETHODIMP scrollSubstringToPoint(LONG start_index,
 276                                       LONG end_index,
 277                                       enum IA2CoordinateType coordinate_type,
 278                                       LONG x,
 279                                       LONG y) override {
 280     return E_NOTIMPL;
 281   }
 282
 283   //
 284   // IServiceProvider methods.
 285   //
 286
 287   STDMETHODIMP QueryService(REFGUID guidService,
 288                             REFIID riid,
 289                             void** object) override;
 290
 291  protected:
 292   AXPlatformNodeWin();
 293
 294  private:
 295   bool IsValidId(const VARIANT& child) const;
 296   int MSAARole();
 297   int MSAAState();
 298   int MSAAEvent(ui::AXEvent event);
 299
 300   HRESULT GetStringAttributeAsBstr(
 301       ui::AXStringAttribute attribute,
 302       BSTR* value_bstr) const;
 303
 304   void AddAlertTarget();
 305   void RemoveAlertTarget();
 306
 307   // Return the text to use for IAccessibleText.
 308   base::string16 TextForIAccessibleText();
 309
 310   // If offset is a member of IA2TextSpecialOffsets this function updates the
 311   // value of offset and returns, otherwise offset remains unchanged.
 312   void HandleSpecialTextOffset(const base::string16& text, LONG* offset);
 313
 314   // Convert from a IA2TextBoundaryType to a ui::TextBoundaryType.
 315   ui::TextBoundaryType IA2TextBoundaryToTextBoundary(IA2TextBoundaryType type);
 316
 317   // Search forwards (direction == 1) or backwards (direction == -1)
 318   // from the given offset until the given boundary is found, and
 319   // return the offset of that boundary.
 320   LONG FindBoundary(const base::string16& text,
 321                     IA2TextBoundaryType ia2_boundary,
 322                     LONG start_offset,
 323                     ui::TextBoundaryDirection direction);
 324
 325   // A windows-specific unique ID for this object. It's returned in
 326   // IAccessible2::get_uniqueID, but more importantly it's used for
 327   // firing events. On Windows, we fire events on the nearest parent HWND
 328   // and pass the unique ID as the child id parameter. When the client
 329   // wants to retrieve the object the event was fired on, it calls
 330   // get_accChild and passes the child ID. We use negative IDs for the unique
 331   // ID so we can distinguish a request for an arbitrary child from a request
 332   // for an immediate child of an object by its 0-based index.
 333   LONG unique_id_win_;
 334 };
 335
 336 }  // namespace ui
 337
 338 #endif  // UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_WIN_H_