Implement computedRole and computedName (behind a flag)

Source/modules/accessibility/AXObject.cpp

Index: Source/modules/accessibility/AXObject.cpp
diff --git a/Source/modules/accessibility/AXObject.cpp b/Source/modules/accessibility/AXObject.cpp
index d4d99c2affaec06beb3b5ba635a6332c91b0ebb0..afd5c64a815474921c57bcedfdf9cf4bb97405bc 100644
--- a/Source/modules/accessibility/AXObject.cpp
+++ b/Source/modules/accessibility/AXObject.cpp
@@ -49,6 +49,7 @@ namespace blink {
 
 using namespace HTMLNames;
 
+namespace {
 typedef HashMap<String, AccessibilityRole, CaseFoldingHash> ARIARoleMap;
 
 struct RoleEntry {
@@ -56,9 +57,9 @@ struct RoleEntry {
     AccessibilityRole webcoreRole;
 };
 
-static ARIARoleMap* createARIARoleMap()
+void fillRoles(Vector<RoleEntry>* rolesVector)
 {
-    const RoleEntry roles[] = {
+    RoleEntry roles[] = {
         { "alert", AlertRole },
         { "alertdialog", AlertDialogRole },
         { "application", ApplicationRole },
@@ -86,7 +87,6 @@ static ARIARoleMap* createARIARoleMap()
         { "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 },
@@ -123,13 +123,41 @@ static ARIARoleMap* createARIARoleMap()
         { "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)
@@ -954,4 +982,13 @@ AccessibilityRole AXObject::buttonRoleType() const
     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