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 "nsIContent.h"
  17 #include "nsIObserver.h"
  18 #include "nsIAccessibleEvent.h"
  19 #include "nsIEventListenerService.h"
  20 #include "nsXULAppAPI.h"
  21 #include "xpcAccessibilityService.h"
  22
  23 class nsImageFrame;
  24 class nsIArray;
  25 class nsIPersistentProperties;
  26 class nsITreeView;
  27
  28 namespace mozilla {
  29
  30 class PresShell;
  31
  32 namespace dom {
  33 class DOMStringList;
  34 class Element;
  35 }  // namespace dom
  36
  37 namespace a11y {
  38
  39 class ApplicationAccessible;
  40 class xpcAccessibleApplication;
  41
  42 /**
  43  * Return focus manager.
  44  */
  45 FocusManager* FocusMgr();
  46
  47 /**
  48  * Return selection manager.
  49  */
  50 SelectionManager* SelectionMgr();
  51
  52 /**
  53  * Returns the application accessible.
  54  */
  55 ApplicationAccessible* ApplicationAcc();
  56 xpcAccessibleApplication* XPCApplicationAcc();
  57
  58 typedef LocalAccessible*(New_Accessible)(mozilla::dom::Element* aElement,
  59                                          LocalAccessible* aContext);
  60
  61 // These fields are not `nsStaticAtom* const` because MSVC doesn't like it.
  62 struct MarkupAttrInfo {
  63   nsStaticAtom* name;
  64   nsStaticAtom* value;
  65
  66   nsStaticAtom* DOMAttrName;
  67   nsStaticAtom* DOMAttrValue;
  68 };
  69
  70 struct MarkupMapInfo {
  71   const nsStaticAtom* const tag;
  72   New_Accessible* new_func;
  73   a11y::role role;
  74   MarkupAttrInfo attrs[4];
  75 };
  76
  77 #ifdef MOZ_XUL
  78 struct XULMarkupMapInfo {
  79   const nsStaticAtom* const tag;
  80   New_Accessible* new_func;
  81 };
  82 #endif
  83
  84 /**
  85  * PREF_ACCESSIBILITY_FORCE_DISABLED preference change callback.
  86  */
  87 void PrefChanged(const char* aPref, void* aClosure);
  88
  89 /**
  90  * Read and normalize PREF_ACCESSIBILITY_FORCE_DISABLED preference.
  91  */
  92 EPlatformDisabledState ReadPlatformDisabledState();
  93
  94 }  // namespace a11y
  95 }  // namespace mozilla
  96
  97 class nsAccessibilityService final : public mozilla::a11y::DocManager,
  98                                      public mozilla::a11y::FocusManager,
  99                                      public mozilla::a11y::SelectionManager,
 100                                      public nsIListenerChangeListener,
 101                                      public nsIObserver {
 102  public:
 103   typedef mozilla::a11y::LocalAccessible LocalAccessible;
 104   typedef mozilla::a11y::DocAccessible DocAccessible;
 105
 106   // nsIListenerChangeListener
 107   NS_IMETHOD ListenersChanged(nsIArray* aEventChanges) override;
 108
 109  protected:
 110   ~nsAccessibilityService();
 111
 112  public:
 113   NS_DECL_ISUPPORTS_INHERITED
 114   NS_DECL_NSIOBSERVER
 115
 116   LocalAccessible* GetRootDocumentAccessible(mozilla::PresShell* aPresShell,
 117                                              bool aCanCreate);
 118
 119   /**
 120    * Adds/remove ATK root accessible for gtk+ native window to/from children
 121    * of the application accessible.
 122    */
 123   LocalAccessible* AddNativeRootAccessible(void* aAtkAccessible);
 124   void RemoveNativeRootAccessible(LocalAccessible* 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   /**
 177    * Notification used to invalidate the isLayoutTable cache.
 178    */
 179   void TableLayoutGuessMaybeChanged(mozilla::PresShell* aPresShell,
 180                                     nsIContent* aContent);
 181
 182   void UpdateText(mozilla::PresShell* aPresShell, nsIContent* aContent);
 183
 184   /**
 185    * Update XUL:tree accessible tree when treeview is changed.
 186    */
 187   void TreeViewChanged(mozilla::PresShell* aPresShell, nsIContent* aContent,
 188                        nsITreeView* aView);
 189
 190   /**
 191    * Notify of input@type="element" value change.
 192    */
 193   void RangeValueChanged(mozilla::PresShell* aPresShell, nsIContent* aContent);
 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, LocalAccessible* aTarget);
 223
 224   /**
 225    * Notify accessibility that the size has become available for an image.
 226    * This occurs when the size of an image is initially not known, but we've
 227    * now loaded enough data to know the size.
 228    * Called by layout.
 229    */
 230   void NotifyOfImageSizeAvailable(mozilla::PresShell* aPresShell,
 231                                   nsIContent* aContent);
 232
 233   // nsAccessibiltiyService
 234
 235   /**
 236    * Return true if accessibility service has been shutdown.
 237    */
 238   static bool IsShutdown() { return gConsumers == 0; };
 239
 240   /**
 241    * Creates an accessible for the given DOM node.
 242    *
 243    * @param  aNode             [in] the given node
 244    * @param  aContext          [in] context the accessible is created in
 245    * @param  aIsSubtreeHidden  [out, optional] indicates whether the node's
 246    *                             frame and its subtree is hidden
 247    */
 248   LocalAccessible* CreateAccessible(nsINode* aNode, LocalAccessible* aContext,
 249                                     bool* aIsSubtreeHidden = nullptr);
 250
 251   mozilla::a11y::role MarkupRole(const nsIContent* aContent) const {
 252     const mozilla::a11y::MarkupMapInfo* markupMap =
 253         GetMarkupMapInfoForNode(aContent);
 254     return markupMap ? markupMap->role : mozilla::a11y::roles::NOTHING;
 255   }
 256
 257   /**
 258    * Return the associated value for a given attribute if
 259    * it appears in the MarkupMap. Otherwise, it returns null.
 260    */
 261   nsStaticAtom* MarkupAttribute(const nsIContent* aContent,
 262                                 nsStaticAtom* aAtom) const {
 263     const mozilla::a11y::MarkupMapInfo* markupMap =
 264         GetMarkupMapInfoForNode(aContent);
 265     if (markupMap) {
 266       for (size_t i = 0; i < mozilla::ArrayLength(markupMap->attrs); i++) {
 267         const mozilla::a11y::MarkupAttrInfo* info = markupMap->attrs + i;
 268         if (info->name == aAtom) {
 269           return info->value;
 270         }
 271       }
 272     }
 273     return nullptr;
 274   }
 275
 276   /**
 277    * Set the object attribute defined by markup for the given element.
 278    */
 279   void MarkupAttributes(const nsIContent* aContent,
 280                         nsIPersistentProperties* aAttributes) const;
 281
 282   /**
 283    * A list of possible accessibility service consumers. Accessibility service
 284    * can only be shut down when there are no remaining consumers.
 285    *
 286    * eXPCOM       - accessibility service is used by XPCOM.
 287    *
 288    * eMainProcess - accessibility service was started by main process in the
 289    *                content process.
 290    *
 291    * ePlatformAPI - accessibility service is used by the platform api in the
 292    *                main process.
 293    */
 294   enum ServiceConsumer {
 295     eXPCOM = 1 << 0,
 296     eMainProcess = 1 << 1,
 297     ePlatformAPI = 1 << 2,
 298   };
 299
 300  private:
 301   // nsAccessibilityService creation is controlled by friend
 302   // GetOrCreateAccService, keep constructors private.
 303   nsAccessibilityService();
 304   nsAccessibilityService(const nsAccessibilityService&);
 305   nsAccessibilityService& operator=(const nsAccessibilityService&);
 306
 307  private:
 308   /**
 309    * Initialize accessibility service.
 310    */
 311   bool Init();
 312
 313   /**
 314    * Shutdowns accessibility service.
 315    */
 316   void Shutdown();
 317
 318   /**
 319    * Create an accessible whose type depends on the given frame.
 320    */
 321   already_AddRefed<LocalAccessible> CreateAccessibleByFrameType(
 322       nsIFrame* aFrame, nsIContent* aContent, LocalAccessible* aContext);
 323
 324   /**
 325    * Notify observers about change of the accessibility service's consumers.
 326    */
 327   void NotifyOfConsumersChange();
 328
 329   /**
 330    * Get a JSON string representing the accessibility service consumers.
 331    */
 332   void GetConsumers(nsAString& aString);
 333
 334   /**
 335    * Set accessibility service consumers.
 336    */
 337   void SetConsumers(uint32_t aConsumers, bool aNotify = true);
 338
 339   /**
 340    * Unset accessibility service consumers.
 341    */
 342   void UnsetConsumers(uint32_t aConsumers);
 343
 344   /**
 345    * Reference for accessibility service instance.
 346    */
 347   static nsAccessibilityService* gAccessibilityService;
 348
 349   /**
 350    * Reference for application accessible instance.
 351    */
 352   static mozilla::a11y::ApplicationAccessible* gApplicationAccessible;
 353   static mozilla::a11y::xpcAccessibleApplication* gXPCApplicationAccessible;
 354
 355   /**
 356    * Contains a set of accessibility service consumers.
 357    */
 358   static uint32_t gConsumers;
 359
 360   using MarkupMap = nsTHashMap<nsPtrHashKey<const nsAtom>,
 361                                const mozilla::a11y::MarkupMapInfo*>;
 362   MarkupMap mHTMLMarkupMap;
 363   MarkupMap mMathMLMarkupMap;
 364
 365   const mozilla::a11y::MarkupMapInfo* GetMarkupMapInfoForNode(
 366       const nsIContent* aContent) const {
 367     if (aContent->IsHTMLElement()) {
 368       return mHTMLMarkupMap.Get(aContent->NodeInfo()->NameAtom());
 369     }
 370     if (aContent->IsMathMLElement()) {
 371       return mMathMLMarkupMap.Get(aContent->NodeInfo()->NameAtom());
 372     }
 373     // This function can be called by MarkupAttribute, etc. which might in turn
 374     // be called on a XUL, SVG, etc. element. For example, this can happen
 375     // with nsAccUtils::SetLiveContainerAttributes.
 376     return nullptr;
 377   }
 378
 379 #ifdef MOZ_XUL
 380   nsTHashMap<nsPtrHashKey<const nsAtom>, const mozilla::a11y::XULMarkupMapInfo*>
 381       mXULMarkupMap;
 382 #endif
 383
 384   friend nsAccessibilityService* GetAccService();
 385   friend nsAccessibilityService* GetOrCreateAccService(uint32_t);
 386   friend void MaybeShutdownAccService(uint32_t);
 387   friend void mozilla::a11y::PrefChanged(const char*, void*);
 388   friend mozilla::a11y::FocusManager* mozilla::a11y::FocusMgr();
 389   friend mozilla::a11y::SelectionManager* mozilla::a11y::SelectionMgr();
 390   friend mozilla::a11y::ApplicationAccessible* mozilla::a11y::ApplicationAcc();
 391   friend mozilla::a11y::xpcAccessibleApplication*
 392   mozilla::a11y::XPCApplicationAcc();
 393   friend class xpcAccessibilityService;
 394 };
 395
 396 /**
 397  * Return the accessibility service instance. (Handy global function)
 398  */
 399 inline nsAccessibilityService* GetAccService() {
 400   return nsAccessibilityService::gAccessibilityService;
 401 }
 402
 403 /**
 404  * Return accessibility service instance; creating one if necessary.
 405  */
 406 nsAccessibilityService* GetOrCreateAccService(
 407     uint32_t aNewConsumer = nsAccessibilityService::ePlatformAPI);
 408
 409 /**
 410  * Shutdown accessibility service if needed.
 411  */
 412 void MaybeShutdownAccService(uint32_t aFormerConsumer);
 413
 414 /**
 415  * Return true if we're in a content process and not B2G.
 416  */
 417 inline bool IPCAccessibilityActive() { return XRE_IsContentProcess(); }
 418
 419 /**
 420  * Map nsIAccessibleEvents constants to strings. Used by
 421  * nsAccessibilityService::GetStringEventType() method.
 422  */
 423 static const char kEventTypeNames[][40] = {
 424     "unknown",                           //
 425     "show",                              // EVENT_SHOW
 426     "hide",                              // EVENT_HIDE
 427     "reorder",                           // EVENT_REORDER
 428     "active decendent change",           // EVENT_ACTIVE_DECENDENT_CHANGED
 429     "focus",                             // EVENT_FOCUS
 430     "state change",                      // EVENT_STATE_CHANGE
 431     "location change",                   // EVENT_LOCATION_CHANGE
 432     "name changed",                      // EVENT_NAME_CHANGE
 433     "description change",                // EVENT_DESCRIPTION_CHANGE
 434     "value change",                      // EVENT_VALUE_CHANGE
 435     "help change",                       // EVENT_HELP_CHANGE
 436     "default action change",             // EVENT_DEFACTION_CHANGE
 437     "action change",                     // EVENT_ACTION_CHANGE
 438     "accelerator change",                // EVENT_ACCELERATOR_CHANGE
 439     "selection",                         // EVENT_SELECTION
 440     "selection add",                     // EVENT_SELECTION_ADD
 441     "selection remove",                  // EVENT_SELECTION_REMOVE
 442     "selection within",                  // EVENT_SELECTION_WITHIN
 443     "alert",                             // EVENT_ALERT
 444     "foreground",                        // EVENT_FOREGROUND
 445     "menu start",                        // EVENT_MENU_START
 446     "menu end",                          // EVENT_MENU_END
 447     "menupopup start",                   // EVENT_MENUPOPUP_START
 448     "menupopup end",                     // EVENT_MENUPOPUP_END
 449     "capture start",                     // EVENT_CAPTURE_START
 450     "capture end",                       // EVENT_CAPTURE_END
 451     "movesize start",                    // EVENT_MOVESIZE_START
 452     "movesize end",                      // EVENT_MOVESIZE_END
 453     "contexthelp start",                 // EVENT_CONTEXTHELP_START
 454     "contexthelp end",                   // EVENT_CONTEXTHELP_END
 455     "dragdrop start",                    // EVENT_DRAGDROP_START
 456     "dragdrop end",                      // EVENT_DRAGDROP_END
 457     "dialog start",                      // EVENT_DIALOG_START
 458     "dialog end",                        // EVENT_DIALOG_END
 459     "scrolling start",                   // EVENT_SCROLLING_START
 460     "scrolling end",                     // EVENT_SCROLLING_END
 461     "minimize start",                    // EVENT_MINIMIZE_START
 462     "minimize end",                      // EVENT_MINIMIZE_END
 463     "document load complete",            // EVENT_DOCUMENT_LOAD_COMPLETE
 464     "document reload",                   // EVENT_DOCUMENT_RELOAD
 465     "document load stopped",             // EVENT_DOCUMENT_LOAD_STOPPED
 466     "document attributes changed",       // EVENT_DOCUMENT_ATTRIBUTES_CHANGED
 467     "document content changed",          // EVENT_DOCUMENT_CONTENT_CHANGED
 468     "property changed",                  // EVENT_PROPERTY_CHANGED
 469     "page changed",                      // EVENT_PAGE_CHANGED
 470     "text attribute changed",            // EVENT_TEXT_ATTRIBUTE_CHANGED
 471     "text caret moved",                  // EVENT_TEXT_CARET_MOVED
 472     "text changed",                      // EVENT_TEXT_CHANGED
 473     "text inserted",                     // EVENT_TEXT_INSERTED
 474     "text removed",                      // EVENT_TEXT_REMOVED
 475     "text updated",                      // EVENT_TEXT_UPDATED
 476     "text selection changed",            // EVENT_TEXT_SELECTION_CHANGED
 477     "visible data changed",              // EVENT_VISIBLE_DATA_CHANGED
 478     "text column changed",               // EVENT_TEXT_COLUMN_CHANGED
 479     "section changed",                   // EVENT_SECTION_CHANGED
 480     "table caption changed",             // EVENT_TABLE_CAPTION_CHANGED
 481     "table model changed",               // EVENT_TABLE_MODEL_CHANGED
 482     "table summary changed",             // EVENT_TABLE_SUMMARY_CHANGED
 483     "table row description changed",     // EVENT_TABLE_ROW_DESCRIPTION_CHANGED
 484     "table row header changed",          // EVENT_TABLE_ROW_HEADER_CHANGED
 485     "table row insert",                  // EVENT_TABLE_ROW_INSERT
 486     "table row delete",                  // EVENT_TABLE_ROW_DELETE
 487     "table row reorder",                 // EVENT_TABLE_ROW_REORDER
 488     "table column description changed",  // EVENT_TABLE_COLUMN_DESCRIPTION_CHANGED
 489     "table column header changed",       // EVENT_TABLE_COLUMN_HEADER_CHANGED
 490     "table column insert",               // EVENT_TABLE_COLUMN_INSERT
 491     "table column delete",               // EVENT_TABLE_COLUMN_DELETE
 492     "table column reorder",              // EVENT_TABLE_COLUMN_REORDER
 493     "window activate",                   // EVENT_WINDOW_ACTIVATE
 494     "window create",                     // EVENT_WINDOW_CREATE
 495     "window deactivate",                 // EVENT_WINDOW_DEACTIVATE
 496     "window destroy",                    // EVENT_WINDOW_DESTROY
 497     "window maximize",                   // EVENT_WINDOW_MAXIMIZE
 498     "window minimize",                   // EVENT_WINDOW_MINIMIZE
 499     "window resize",                     // EVENT_WINDOW_RESIZE
 500     "window restore",                    // EVENT_WINDOW_RESTORE
 501     "hyperlink end index changed",       // EVENT_HYPERLINK_END_INDEX_CHANGED
 502     "hyperlink number of anchors changed",  // EVENT_HYPERLINK_NUMBER_OF_ANCHORS_CHANGED
 503     "hyperlink selected link changed",  // EVENT_HYPERLINK_SELECTED_LINK_CHANGED
 504     "hypertext link activated",         // EVENT_HYPERTEXT_LINK_ACTIVATED
 505     "hypertext link selected",          // EVENT_HYPERTEXT_LINK_SELECTED
 506     "hyperlink start index changed",    // EVENT_HYPERLINK_START_INDEX_CHANGED
 507     "hypertext changed",                // EVENT_HYPERTEXT_CHANGED
 508     "hypertext links count changed",    // EVENT_HYPERTEXT_NLINKS_CHANGED
 509     "object attribute changed",         // EVENT_OBJECT_ATTRIBUTE_CHANGED
 510     "virtual cursor changed",           // EVENT_VIRTUALCURSOR_CHANGED
 511     "text value change",                // EVENT_TEXT_VALUE_CHANGE
 512     "scrolling",                        // EVENT_SCROLLING
 513     "announcement",                     // EVENT_ANNOUNCEMENT
 514     "live region added",                // EVENT_LIVE_REGION_ADDED
 515     "live region removed",              // EVENT_LIVE_REGION_REMOVED
 516     "table styling changed",            // EVENT_TABLE_STYLING_CHANGED
 517 };
 518
 519 #endif