Implement computedRole and computedName (behind a flag)

Source/modules/accessibility/AXObject.cpp

 /*
  * Copyright (C) 2008, 2009, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 31 matching lines @@
 #include "platform/text/PlatformLocale.h"
 #include "wtf/StdLibExtras.h"
 #include "wtf/text/WTFString.h"
 
 using blink::WebLocalizedString;
 
 namespace blink {
 
 using namespace HTMLNames;
 
+namespace {
 typedef HashMap<String, AccessibilityRole, CaseFoldingHash> ARIARoleMap;
 
 struct RoleEntry {
     String ariaRole;
     AccessibilityRole webcoreRole;
 };
 
-static ARIARoleMap* createARIARoleMap()
+void fillRoles(Vector<RoleEntry>* rolesVector)
 {
-    const RoleEntry roles[] = {
+    RoleEntry roles[] = {
         { "alert", AlertRole },
         { "alertdialog", AlertDialogRole },
         { "application", ApplicationRole },
         { "article", ArticleRole },
         { "banner", BannerRole },
         { "button", ButtonRole },
         { "checkbox", CheckBoxRole },
         { "complementary", ComplementaryRole },
         { "contentinfo", ContentInfoRole },
         { "dialog", DialogRole },
         { "directory", DirectoryRole },
         { "grid", GridRole },
         { "gridcell", CellRole },
         { "columnheader", ColumnHeaderRole },
         { "combobox", ComboBoxRole },
         { "definition", DefinitionRole },
         { "document", DocumentRole },
         { "rowheader", RowHeaderRole },
         { "form", FormRole },
         { "group", GroupRole },
         { "heading", HeadingRole },
         { "img", ImageRole },
         { "link", LinkRole },
         { "list", ListRole },
         { "listitem", ListItemRole },
         { "listbox", ListBoxRole },
         { "log", LogRole },
-        // "option" isn't here because it may map to different roles depending on the parent element's role
         { "main", MainRole },
         { "marquee", MarqueeRole },
         { "math", MathRole },
         { "menu", MenuRole },
         { "menubar", MenuBarRole },
         { "menuitem", MenuItemRole },
         { "menuitemcheckbox", MenuItemCheckBoxRole },
         { "menuitemradio", MenuItemRadioRole },
         { "note", NoteRole },
         { "navigation", NavigationRole },
@@ skipping 16 matching lines @@
         { "tabpanel", TabPanelRole },
         { "text", StaticTextRole },
         { "textbox", TextAreaRole },
         { "timer", TimerRole },
         { "toolbar", ToolbarRole },
         { "tooltip", UserInterfaceTooltipRole },
         { "tree", TreeRole },
         { "treegrid", TreeGridRole },
         { "treeitem", TreeItemRole }
     };
+    size_t numRoles = WTF_ARRAY_LENGTH(roles);
+    rolesVector->resize(numRoles);
+    for (size_t i = 0; i < numRoles; ++i)
+        rolesVector->at(i) = roles[i];
+}
+
+static ARIARoleMap* createARIARoleMap()
+{
     ARIARoleMap* roleMap = new ARIARoleMap;
 
-    for (size_t i = 0; i < WTF_ARRAY_LENGTH(roles); ++i)
+    Vector<RoleEntry> roles;
+    fillRoles(&roles);
+    for (size_t i = 0; i < roles.size(); ++i)
         roleMap->set(roles[i].ariaRole, roles[i].webcoreRole);
     return roleMap;
 }
 
+static Vector<AtomicString>* createRoleNameVector()

[adamk, 2014/12/16 01:54:49]

Sorry, I'm having trouble figuring out exactly why we need this vector, can you
explain?

[aboxhall, 2014/12/16 04:15:26]

It's just a map of role enum to name; used on line 991. If there's an
obvious-to-you better way to do this, please don't assume it's obvious to me; I
would be very glad to hear it :)

[adamk, 2014/12/16 18:25:15]

What about making the array of roles statically scoped to the file, and then
indexing into that in roleName()? You could even add a COMPILE_ASSERT that the
array has the right length, which would make your ASSERT below a compile-time
instead of a runtime error. I guess what I'm missing is what the Vector is
buying you that the array doesn't get you already.

[aboxhall, 2014/12/17 22:21:26]

Sorry, I missed this comment.

I think what you're missing is that roles[] is a subset of roleNameVector -
there are more values in AccessibilityRole than there are ARIA roles (which is
what roles[] is indexing).

+{
+    Vector<AtomicString>* roleNameVector = new Vector<AtomicString>;
+    roleNameVector->resize(NumRoles);
+    for (int i = 0; i < NumRoles; i++)
+        roleNameVector->at(i) = nullAtom;
+
+    Vector<RoleEntry> roles;
+    fillRoles(&roles);
+
+    for (size_t i = 0; i < roles.size(); ++i)
+        (*roleNameVector)[roles[i].webcoreRole] = AtomicString(roles[i].ariaRole);
+
+    return roleNameVector;
+}
+
+} // namespace
+
 AXObject::AXObject(AXObjectCacheImpl* axObjectCache)
     : m_id(0)
     , m_haveChildren(false)
     , m_role(UnknownRole)
     , m_lastKnownIsIgnoredValue(DefaultBehavior)
     , m_detached(false)
     , m_parent(0)
     , m_lastModificationCount(-1)
     , m_cachedIsIgnored(false)
     , m_cachedLiveRegionRoot(0)
@@ skipping 804 matching lines @@
     if (ariaPressedIsPresent())
         return ToggleButtonRole;
     if (ariaHasPopup())
         return PopUpButtonRole;
     // We don't contemplate RadioButtonRole, as it depends on the input
     // type.
 
     return ButtonRole;
 }
 
+const AtomicString& AXObject::roleName(const AccessibilityRole role)
+{
+    static const Vector<AtomicString>* roleNameVector = createRoleNameVector();
+
+    // TODO(aboxhall): assert with security (maybe)
+    ASSERT(role < roleNameVector->size());
+    return roleNameVector->at(role);
+}
+
 } // namespace blink