Bug 1551684 part 2. Stop using [array] in nsIAccessiblePivot. r=surkov

Differential Revision: https://phabricator.services.mozilla.com/D31180

--HG--
extra : moz-landing-system : lando

accessible/base/nsAccessiblePivot.cpp

@@ -10,8 +10,11 @@
 #include "nsAccUtils.h"
 #include "States.h"
 #include "xpcAccessibleDocument.h"
+#include "nsTArray.h"
+#include "mozilla/Maybe.h"
 
 using namespace mozilla::a11y;
+using mozilla::Maybe;
 
 /**
  * An object that stores a given traversal rule during the pivot movement.
@@ -19,20 +22,14 @@ using namespace mozilla::a11y;
 class RuleCache {
  public:
   explicit RuleCache(nsIAccessibleTraversalRule* aRule)
-      : mRule(aRule),
+      : mRule(aRule), mPreFilter{0} {}
-        mAcceptRoles(nullptr),
+  ~RuleCache() {}
-        mAcceptRolesLength{0},
-        mPreFilter{0} {}
-  ~RuleCache() {
-    if (mAcceptRoles) free(mAcceptRoles);
-  }
 
   nsresult ApplyFilter(Accessible* aAccessible, uint16_t* aResult);
 
  private:
   nsCOMPtr<nsIAccessibleTraversalRule> mRule;
-  uint32_t* mAcceptRoles;
+  Maybe<nsTArray<uint32_t>> mAcceptRoles;
-  uint32_t mAcceptRolesLength;
   uint32_t mPreFilter;
 };
 
@@ -822,7 +819,7 @@ bool nsAccessiblePivot::NotifyOfPivotChange(Accessible* aOldPosition,
     return false;
 
   nsCOMPtr<nsIAccessible> xpcOldPos = ToXPC(aOldPosition);  // death grip
-  nsTObserverArray<nsCOMPtr<nsIAccessiblePivotObserver> >::ForwardIterator iter(
+  nsTObserverArray<nsCOMPtr<nsIAccessiblePivotObserver>>::ForwardIterator iter(
       mObservers);
   while (iter.HasMore()) {
     nsIAccessiblePivotObserver* obs = iter.GetNext();
@@ -838,7 +835,8 @@ nsresult RuleCache::ApplyFilter(Accessible* aAccessible, uint16_t* aResult) {
   *aResult = nsIAccessibleTraversalRule::FILTER_IGNORE;
 
   if (!mAcceptRoles) {
-    nsresult rv = mRule->GetMatchRoles(&mAcceptRoles, &mAcceptRolesLength);
+    mAcceptRoles.emplace();
+    nsresult rv = mRule->GetMatchRoles(*mAcceptRoles);
     NS_ENSURE_SUCCESS(rv, rv);
     rv = mRule->GetPreFilter(&mPreFilter);
     NS_ENSURE_SUCCESS(rv, rv);
@@ -874,11 +872,11 @@ nsresult RuleCache::ApplyFilter(Accessible* aAccessible, uint16_t* aResult) {
     }
   }
 
-  if (mAcceptRolesLength > 0) {
+  if (mAcceptRoles->Length() > 0) {
     uint32_t accessibleRole = aAccessible->Role();
     bool matchesRole = false;
-    for (uint32_t idx = 0; idx < mAcceptRolesLength; idx++) {
+    for (uint32_t idx = 0; idx < mAcceptRoles->Length(); idx++) {
-      matchesRole = mAcceptRoles[idx] == accessibleRole;
+      matchesRole = mAcceptRoles->ElementAt(idx) == accessibleRole;
       if (matchesRole) break;
     }
     if (!matchesRole) return NS_OK;

accessible/interfaces/nsIAccessiblePivot.idl

@@ -245,11 +245,9 @@ interface nsIAccessibleTraversalRule : nsISupports
    * at the start of a traversal, so changing the method's return result after
    * that would have no affect.
    *
-   * @param aRoles [out] an array of the roles to match.
+   * @return an array of the roles to match.
-   * @param aCount [out] the length of the array.
    */
-  void getMatchRoles([array, size_is(aCount)]out unsigned long aRoles,
+  Array<unsigned long> getMatchRoles();
-                     [retval]out unsigned long aCount);
 
   /**
    * Determines if a given accessible is to be accepted in our traversal rule

accessible/jsat/Traversal.jsm

@@ -36,9 +36,8 @@ function BaseTraversalRule(aRoles, aMatchFunc, aPreFilter, aContainerRule) {
 }
 
 BaseTraversalRule.prototype = {
-    getMatchRoles: function BaseTraversalRule_getmatchRoles(aRoles) {
+    getMatchRoles: function BaseTraversalRule_getmatchRoles() {
-      aRoles.value = this._matchRoles;
+      return this._matchRoles;
-      return aRoles.value.length;
     },
 
     match: function BaseTraversalRule_match(aAccessible) {

accessible/tests/mochitest/pivot.js

@@ -23,9 +23,8 @@ const NS_ERROR_INVALID_ARG = 0x80070057;
  */
 var HeadersTraversalRule =
 {
-  getMatchRoles(aRules) {
+  getMatchRoles() {
-    aRules.value = [ROLE_HEADING];
+    return [ROLE_HEADING];
-    return aRules.value.length;
   },
 
   preFilter: PREFILTER_INVISIBLE,
@@ -42,9 +41,8 @@ var HeadersTraversalRule =
  */
 var ObjectTraversalRule =
 {
-  getMatchRoles(aRules) {
+  getMatchRoles() {
-    aRules.value = [];
+    return [];
-    return 0;
   },
 
   preFilter: PREFILTER_INVISIBLE | PREFILTER_TRANSPARENT,