accessible/base/nsAccessibilityService.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef __nsAccessibilityService_h__
   7 #define __nsAccessibilityService_h__
   8
   9 #include "mozilla/a11y/DocManager.h"
  10 #include "mozilla/a11y/FocusManager.h"
  11 #include "mozilla/a11y/Platform.h"
  12 #include "mozilla/a11y/Role.h"
  13 #include "mozilla/a11y/SelectionManager.h"
  14 #include "mozilla/Preferences.h"
  15
  16 #include "nsIObserver.h"
  17 #include "nsIAccessibleEvent.h"
  18 #include "nsIEventListenerService.h"
  19 #include "xpcAccessibilityService.h"
  20
  21 class nsImageFrame;
  22 class nsIArray;
  23 class nsIPersistentProperties;
  24 class nsPluginFrame;
  25 class nsITreeView;
  26
  27 namespace mozilla {
  28
  29 class PresShell;
  30
  31 namespace dom {
  32 class DOMStringList;
  33 }
  34
  35 namespace a11y {
  36
  37 class ApplicationAccessible;
  38 class xpcAccessibleApplication;
  39
  40 /**
  41  * Return focus manager.
  42  */
  43 FocusManager* FocusMgr();
  44
  45 /**
  46  * Return selection manager.
  47  */
  48 SelectionManager* SelectionMgr();
  49
  50 /**
  51  * Returns the application accessible.
  52  */
  53 ApplicationAccessible* ApplicationAcc();
  54 xpcAccessibleApplication* XPCApplicationAcc();
  55
  56 typedef Accessible*(New_Accessible)(Element* aElement, Accessible* aContext);
  57
  58 // These fields are not `nsStaticAtom* const` because MSVC doesn't like it.
  59 struct MarkupAttrInfo {
  60   nsStaticAtom* name;
  61   nsStaticAtom* value;
  62
  63   nsStaticAtom* DOMAttrName;
  64   nsStaticAtom* DOMAttrValue;
  65 };
  66
  67 struct HTMLMarkupMapInfo {
  68   const nsStaticAtom* const tag;
  69   New_Accessible* new_func;
  70   a11y::role role;
  71   MarkupAttrInfo attrs[4];
  72 };
  73
  74 #ifdef MOZ_XUL
  75 struct XULMarkupMapInfo {
  76   const nsStaticAtom* const tag;
  77   New_Accessible* new_func;
  78 };
  79 #endif
  80
  81 /**
  82  * PREF_ACCESSIBILITY_FORCE_DISABLED preference change callback.
  83  */
  84 void PrefChanged(const char* aPref, void* aClosure);
  85
  86 /**
  87  * Read and normalize PREF_ACCESSIBILITY_FORCE_DISABLED preference.
  88  */
  89 EPlatformDisabledState ReadPlatformDisabledState();
  90
  91 }  // namespace a11y
  92 }  // namespace mozilla
  93
  94 class nsAccessibilityService final : public mozilla::a11y::DocManager,
  95                                      public mozilla::a11y::FocusManager,
  96                                      public mozilla::a11y::SelectionManager,
  97                                      public nsIListenerChangeListener,
  98                                      public nsIObserver {
  99  public:
 100   typedef mozilla::a11y::Accessible Accessible;
 101   typedef mozilla::a11y::DocAccessible DocAccessible;
 102
 103   // nsIListenerChangeListener
 104   NS_IMETHOD ListenersChanged(nsIArray* aEventChanges) override;
 105
 106  protected:
 107   ~nsAccessibilityService();
 108
 109  public:
 110   NS_DECL_ISUPPORTS_INHERITED
 111   NS_DECL_NSIOBSERVER
 112
 113   Accessible* GetRootDocumentAccessible(mozilla::PresShell* aPresShell,
 114                                         bool aCanCreate);
 115   already_AddRefed<Accessible> CreatePluginAccessible(nsPluginFrame* aFrame,
 116                                                       nsIContent* aContent,
 117                                                       Accessible* aContext);
 118
 119   /**
 120    * Adds/remove ATK root accessible for gtk+ native window to/from children
 121    * of the application accessible.
 122    */
 123   Accessible* AddNativeRootAccessible(void* aAtkAccessible);
 124   void RemoveNativeRootAccessible(Accessible* aRootAccessible);
 125
 126   bool HasAccessible(nsINode* aDOMNode);
 127
 128   /**
 129    * Get a string equivalent for an accessible role value.
 130    */
 131   void GetStringRole(uint32_t aRole, nsAString& aString);
 132
 133   /**
 134    * Get a string equivalent for an accessible state/extra state.
 135    */
 136   already_AddRefed<mozilla::dom::DOMStringList> GetStringStates(
 137       uint64_t aStates) const;
 138   void GetStringStates(uint32_t aState, uint32_t aExtraState,
 139                        nsISupports** aStringStates);
 140
 141   /**
 142    * Get a string equivalent for an accessible event value.
 143    */
 144   void GetStringEventType(uint32_t aEventType, nsAString& aString);
 145
 146   /**
 147    * Get a string equivalent for an accessible event value.
 148    */
 149   void GetStringEventType(uint32_t aEventType, nsACString& aString);
 150
 151   /**
 152    * Get a string equivalent for an accessible relation type.
 153    */
 154   void GetStringRelationType(uint32_t aRelationType, nsAString& aString);
 155
 156   // nsAccesibilityService
 157   /**
 158    * Notification used to update the accessible tree when deck panel is
 159    * switched.
 160    */
 161   void DeckPanelSwitched(mozilla::PresShell* aPresShell, nsIContent* aDeckNode,
 162                          nsIFrame* aPrevBoxFrame, nsIFrame* aCurrentBoxFrame);
 163
 164   /**
 165    * Notification used to update the accessible tree when new content is
 166    * inserted.
 167    */
 168   void ContentRangeInserted(mozilla::PresShell* aPresShell,
 169                             nsIContent* aStartChild, nsIContent* aEndChild);
 170
 171   /**
 172    * Notification used to update the accessible tree when content is removed.
 173    */
 174   void ContentRemoved(mozilla::PresShell* aPresShell, nsIContent* aChild);
 175
 176   void UpdateText(mozilla::PresShell* aPresShell, nsIContent* aContent);
 177
 178   /**
 179    * Update XUL:tree accessible tree when treeview is changed.
 180    */
 181   void TreeViewChanged(mozilla::PresShell* aPresShell, nsIContent* aContent,
 182                        nsITreeView* aView);
 183
 184   /**
 185    * Notify of input@type="element" value change.
 186    */
 187   void RangeValueChanged(mozilla::PresShell* aPresShell, nsIContent* aContent);
 188
 189   /**
 190    * Update list bullet accessible.
 191    */
 192   void UpdateListBullet(mozilla::PresShell* aPresShell,
 193                         nsIContent* aHTMLListItemContent, bool aHasBullet);
 194
 195   /**
 196    * Update the image map.
 197    */
 198   void UpdateImageMap(nsImageFrame* aImageFrame);
 199
 200   /**
 201    * Update the label accessible tree when rendered @value is changed.
 202    */
 203   void UpdateLabelValue(mozilla::PresShell* aPresShell, nsIContent* aLabelElm,
 204                         const nsString& aNewValue);
 205
 206   /**
 207    * Notify accessibility that anchor jump has been accomplished to the given
 208    * target. Used by layout.
 209    */
 210   void NotifyOfAnchorJumpTo(nsIContent* aTarget);
 211
 212   /**
 213    * Notify that presshell is activated.
 214    */
 215   void PresShellActivated(mozilla::PresShell* aPresShell);
 216
 217   /**
 218    * Recreate an accessible for the given content node in the presshell.
 219    */
 220   void RecreateAccessible(mozilla::PresShell* aPresShell, nsIContent* aContent);
 221
 222   void FireAccessibleEvent(uint32_t aEvent, Accessible* aTarget);
 223
 224   // nsAccessibiltiyService
 225
 226   /**
 227    * Return true if accessibility service has been shutdown.
 228    */
 229   static bool IsShutdown() { return gConsumers == 0; };
 230
 231   /**
 232    * Creates an accessible for the given DOM node.
 233    *
 234    * @param  aNode             [in] the given node
 235    * @param  aContext          [in] context the accessible is created in
 236    * @param  aIsSubtreeHidden  [out, optional] indicates whether the node's
 237    *                             frame and its subtree is hidden
 238    */
 239   Accessible* CreateAccessible(nsINode* aNode, Accessible* aContext,
 240                                bool* aIsSubtreeHidden = nullptr);
 241
 242   mozilla::a11y::role MarkupRole(const nsIContent* aContent) const {
 243     const mozilla::a11y::HTMLMarkupMapInfo* markupMap =
 244         mHTMLMarkupMap.Get(aContent->NodeInfo()->NameAtom());
 245     return markupMap ? markupMap->role : mozilla::a11y::roles::NOTHING;
 246   }
 247
 248   /**
 249    * Set the object attribute defined by markup for the given element.
 250    */
 251   void MarkupAttributes(const nsIContent* aContent,
 252                         nsIPersistentProperties* aAttributes) const;
 253
 254   /**
 255    * A list of possible accessibility service consumers. Accessibility service
 256    * can only be shut down when there are no remaining consumers.
 257    *
 258    * eXPCOM       - accessibility service is used by XPCOM.
 259    *
 260    * eMainProcess - accessibility service was started by main process in the
 261    *                content process.
 262    *
 263    * ePlatformAPI - accessibility service is used by the platform api in the
 264    *                main process.
 265    */
 266   enum ServiceConsumer {
 267     eXPCOM = 1 << 0,
 268     eMainProcess = 1 << 1,
 269     ePlatformAPI = 1 << 2,
 270   };
 271
 272  private:
 273   // nsAccessibilityService creation is controlled by friend
 274   // GetOrCreateAccService, keep constructors private.
 275   nsAccessibilityService();
 276   nsAccessibilityService(const nsAccessibilityService&);
 277   nsAccessibilityService& operator=(const nsAccessibilityService&);
 278
 279  private:
 280   /**
 281    * Initialize accessibility service.
 282    */
 283   bool Init();
 284
 285   /**
 286    * Shutdowns accessibility service.
 287    */
 288   void Shutdown();
 289
 290   /**
 291    * Create an accessible whose type depends on the given frame.
 292    */
 293   already_AddRefed<Accessible> CreateAccessibleByFrameType(
 294       nsIFrame* aFrame, nsIContent* aContent, Accessible* aContext);
 295
 296   /**
 297    * Notify observers about change of the accessibility service's consumers.
 298    */
 299   void NotifyOfConsumersChange();
 300
 301   /**
 302    * Get a JSON string representing the accessibility service consumers.
 303    */
 304   void GetConsumers(nsAString& aString);
 305
 306   /**
 307    * Set accessibility service consumers.
 308    */
 309   void SetConsumers(uint32_t aConsumers, bool aNotify = true);
 310
 311   /**
 312    * Unset accessibility service consumers.
 313    */
 314   void UnsetConsumers(uint32_t aConsumers);
 315
 316   /**
 317    * Reference for accessibility service instance.
 318    */
 319   static nsAccessibilityService* gAccessibilityService;
 320
 321   /**
 322    * Reference for application accessible instance.
 323    */
 324   static mozilla::a11y::ApplicationAccessible* gApplicationAccessible;
 325   static mozilla::a11y::xpcAccessibleApplication* gXPCApplicationAccessible;
 326
 327   /**
 328    * Contains a set of accessibility service consumers.
 329    */
 330   static uint32_t gConsumers;
 331
 332   nsDataHashtable<nsPtrHashKey<const nsAtom>,
 333                   const mozilla::a11y::HTMLMarkupMapInfo*>
 334       mHTMLMarkupMap;
 335 #ifdef MOZ_XUL
 336   nsDataHashtable<nsPtrHashKey<const nsAtom>,
 337                   const mozilla::a11y::XULMarkupMapInfo*>
 338       mXULMarkupMap;
 339 #endif
 340
 341   friend nsAccessibilityService* GetAccService();
 342   friend nsAccessibilityService* GetOrCreateAccService(uint32_t);
 343   friend void MaybeShutdownAccService(uint32_t);
 344   friend void mozilla::a11y::PrefChanged(const char*, void*);
 345   friend mozilla::a11y::FocusManager* mozilla::a11y::FocusMgr();
 346   friend mozilla::a11y::SelectionManager* mozilla::a11y::SelectionMgr();
 347   friend mozilla::a11y::ApplicationAccessible* mozilla::a11y::ApplicationAcc();
 348   friend mozilla::a11y::xpcAccessibleApplication*
 349   mozilla::a11y::XPCApplicationAcc();
 350   friend class xpcAccessibilityService;
 351 };
 352
 353 /**
 354  * Return the accessibility service instance. (Handy global function)
 355  */
 356 inline nsAccessibilityService* GetAccService() {
 357   return nsAccessibilityService::gAccessibilityService;
 358 }
 359
 360 /**
 361  * Return accessibility service instance; creating one if necessary.
 362  */
 363 nsAccessibilityService* GetOrCreateAccService(
 364     uint32_t aNewConsumer = nsAccessibilityService::ePlatformAPI);
 365
 366 /**
 367  * Shutdown accessibility service if needed.
 368  */
 369 void MaybeShutdownAccService(uint32_t aFormerConsumer);
 370
 371 /**
 372  * Return true if we're in a content process and not B2G.
 373  */
 374 inline bool IPCAccessibilityActive() { return XRE_IsContentProcess(); }
 375
 376 /**
 377  * Map nsIAccessibleEvents constants to strings. Used by
 378  * nsAccessibilityService::GetStringEventType() method.
 379  */
 380 static const char kEventTypeNames[][40] = {
 381     "unknown",                           //
 382     "show",                              // EVENT_SHOW
 383     "hide",                              // EVENT_HIDE
 384     "reorder",                           // EVENT_REORDER
 385     "active decendent change",           // EVENT_ACTIVE_DECENDENT_CHANGED
 386     "focus",                             // EVENT_FOCUS
 387     "state change",                      // EVENT_STATE_CHANGE
 388     "location change",                   // EVENT_LOCATION_CHANGE
 389     "name changed",                      // EVENT_NAME_CHANGE
 390     "description change",                // EVENT_DESCRIPTION_CHANGE
 391     "value change",                      // EVENT_VALUE_CHANGE
 392     "help change",                       // EVENT_HELP_CHANGE
 393     "default action change",             // EVENT_DEFACTION_CHANGE
 394     "action change",                     // EVENT_ACTION_CHANGE
 395     "accelerator change",                // EVENT_ACCELERATOR_CHANGE
 396     "selection",                         // EVENT_SELECTION
 397     "selection add",                     // EVENT_SELECTION_ADD
 398     "selection remove",                  // EVENT_SELECTION_REMOVE
 399     "selection within",                  // EVENT_SELECTION_WITHIN
 400     "alert",                             // EVENT_ALERT
 401     "foreground",                        // EVENT_FOREGROUND
 402     "menu start",                        // EVENT_MENU_START
 403     "menu end",                          // EVENT_MENU_END
 404     "menupopup start",                   // EVENT_MENUPOPUP_START
 405     "menupopup end",                     // EVENT_MENUPOPUP_END
 406     "capture start",                     // EVENT_CAPTURE_START
 407     "capture end",                       // EVENT_CAPTURE_END
 408     "movesize start",                    // EVENT_MOVESIZE_START
 409     "movesize end",                      // EVENT_MOVESIZE_END
 410     "contexthelp start",                 // EVENT_CONTEXTHELP_START
 411     "contexthelp end",                   // EVENT_CONTEXTHELP_END
 412     "dragdrop start",                    // EVENT_DRAGDROP_START
 413     "dragdrop end",                      // EVENT_DRAGDROP_END
 414     "dialog start",                      // EVENT_DIALOG_START
 415     "dialog end",                        // EVENT_DIALOG_END
 416     "scrolling start",                   // EVENT_SCROLLING_START
 417     "scrolling end",                     // EVENT_SCROLLING_END
 418     "minimize start",                    // EVENT_MINIMIZE_START
 419     "minimize end",                      // EVENT_MINIMIZE_END
 420     "document load complete",            // EVENT_DOCUMENT_LOAD_COMPLETE
 421     "document reload",                   // EVENT_DOCUMENT_RELOAD
 422     "document load stopped",             // EVENT_DOCUMENT_LOAD_STOPPED
 423     "document attributes changed",       // EVENT_DOCUMENT_ATTRIBUTES_CHANGED
 424     "document content changed",          // EVENT_DOCUMENT_CONTENT_CHANGED
 425     "property changed",                  // EVENT_PROPERTY_CHANGED
 426     "page changed",                      // EVENT_PAGE_CHANGED
 427     "text attribute changed",            // EVENT_TEXT_ATTRIBUTE_CHANGED
 428     "text caret moved",                  // EVENT_TEXT_CARET_MOVED
 429     "text changed",                      // EVENT_TEXT_CHANGED
 430     "text inserted",                     // EVENT_TEXT_INSERTED
 431     "text removed",                      // EVENT_TEXT_REMOVED
 432     "text updated",                      // EVENT_TEXT_UPDATED
 433     "text selection changed",            // EVENT_TEXT_SELECTION_CHANGED
 434     "visible data changed",              // EVENT_VISIBLE_DATA_CHANGED
 435     "text column changed",               // EVENT_TEXT_COLUMN_CHANGED
 436     "section changed",                   // EVENT_SECTION_CHANGED
 437     "table caption changed",             // EVENT_TABLE_CAPTION_CHANGED
 438     "table model changed",               // EVENT_TABLE_MODEL_CHANGED
 439     "table summary changed",             // EVENT_TABLE_SUMMARY_CHANGED
 440     "table row description changed",     // EVENT_TABLE_ROW_DESCRIPTION_CHANGED
 441     "table row header changed",          // EVENT_TABLE_ROW_HEADER_CHANGED
 442     "table row insert",                  // EVENT_TABLE_ROW_INSERT
 443     "table row delete",                  // EVENT_TABLE_ROW_DELETE
 444     "table row reorder",                 // EVENT_TABLE_ROW_REORDER
 445     "table column description changed",  // EVENT_TABLE_COLUMN_DESCRIPTION_CHANGED
 446     "table column header changed",       // EVENT_TABLE_COLUMN_HEADER_CHANGED
 447     "table column insert",               // EVENT_TABLE_COLUMN_INSERT
 448     "table column delete",               // EVENT_TABLE_COLUMN_DELETE
 449     "table column reorder",              // EVENT_TABLE_COLUMN_REORDER
 450     "window activate",                   // EVENT_WINDOW_ACTIVATE
 451     "window create",                     // EVENT_WINDOW_CREATE
 452     "window deactivate",                 // EVENT_WINDOW_DEACTIVATE
 453     "window destroy",                    // EVENT_WINDOW_DESTROY
 454     "window maximize",                   // EVENT_WINDOW_MAXIMIZE
 455     "window minimize",                   // EVENT_WINDOW_MINIMIZE
 456     "window resize",                     // EVENT_WINDOW_RESIZE
 457     "window restore",                    // EVENT_WINDOW_RESTORE
 458     "hyperlink end index changed",       // EVENT_HYPERLINK_END_INDEX_CHANGED
 459     "hyperlink number of anchors changed",  // EVENT_HYPERLINK_NUMBER_OF_ANCHORS_CHANGED
 460     "hyperlink selected link changed",  // EVENT_HYPERLINK_SELECTED_LINK_CHANGED
 461     "hypertext link activated",         // EVENT_HYPERTEXT_LINK_ACTIVATED
 462     "hypertext link selected",          // EVENT_HYPERTEXT_LINK_SELECTED
 463     "hyperlink start index changed",    // EVENT_HYPERLINK_START_INDEX_CHANGED
 464     "hypertext changed",                // EVENT_HYPERTEXT_CHANGED
 465     "hypertext links count changed",    // EVENT_HYPERTEXT_NLINKS_CHANGED
 466     "object attribute changed",         // EVENT_OBJECT_ATTRIBUTE_CHANGED
 467     "virtual cursor changed",           // EVENT_VIRTUALCURSOR_CHANGED
 468     "text value change",                // EVENT_TEXT_VALUE_CHANGE
 469     "scrolling",                        // EVENT_SCROLLING
 470     "announcement",                     // EVENT_ANNOUNCEMENT
 471 };
 472
 473 #endif