bug 856790 - make nsTArray::EnsureLengthAtleast() return void r=jlebar

xpcom/glue/nsCOMArray.cpp

@@ -169,14 +169,13 @@ nsCOMArray_base::InsertElementsAt(uint32_t aIndex, nsISupports* const* aElements
 bool
 nsCOMArray_base::ReplaceObjectAt(nsISupports* aObject, int32_t aIndex)
 {
-    bool result = mArray.EnsureLengthAtLeast(aIndex + 1);
-    if (result) {
-        nsISupports *oldObject = mArray[aIndex];
-        // Make sure to addref first, in case aObject == oldObject
-        NS_IF_ADDREF(mArray[aIndex] = aObject);
-        NS_IF_RELEASE(oldObject);
-    }
-    return result;
+  mArray.EnsureLengthAtLeast(aIndex + 1);
+  nsISupports *oldObject = mArray[aIndex];
+  // Make sure to addref first, in case aObject == oldObject
+  NS_IF_ADDREF(mArray[aIndex] = aObject);
+  NS_IF_RELEASE(oldObject);
+  // XXX make this return void
+  return true;
 }
 
 bool

xpcom/glue/nsTArray.h

@@ -131,6 +131,10 @@ struct nsTArrayFallibleAllocatorBase
   static ResultTypeProxy FailureResult() {
     return false;
   }
+
+  static ResultType ConvertBoolToResultType(bool aValue) {
+    return aValue;
+  }
 };
 
 struct nsTArrayInfallibleAllocatorBase
@@ -153,6 +157,12 @@ struct nsTArrayInfallibleAllocatorBase
     NS_RUNTIMEABORT("Infallible nsTArray should never fail");
     return ResultTypeProxy();
   }
+
+  static ResultType ConvertBoolToResultType(bool aValue) {
+    if (!aValue) {
+      NS_RUNTIMEABORT("infallible nsTArray should never convert false to ResultType");
+    }
+  }
 };
 
 #if defined(MOZALLOC_HAVE_XMALLOC)
@@ -1215,12 +1225,12 @@ public:
   // constructor.
   // @param minLen  The desired minimum length of this array.
   // @return        True if the operation succeeded; false otherwise.
-  bool EnsureLengthAtLeast(size_type minLen) {
+typename Alloc::ResultType EnsureLengthAtLeast(size_type minLen) {
     size_type oldLen = Length();
     if (minLen > oldLen) {
-      return InsertElementsAt(oldLen, minLen - oldLen) != nullptr;
+      return Alloc::ConvertBoolToResultType(!!InsertElementsAt(oldLen, minLen - oldLen));
     }
-    return true;
+    return Alloc::ConvertBoolToResultType(true);
   }
 
   // This method inserts elements into the array, constructing