Bug 1546697 - EnumeratedArray should have a copy assignment operator. r=froydnj

I'll use this in a following patch.

Differential Revision: https://phabricator.services.mozilla.com/D28679

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

mfbt/EnumeratedArray.h

@@ -80,6 +80,13 @@ class EnumeratedArray {
     return *this;
   }
 
+  EnumeratedArray& operator=(const EnumeratedArray& aOther) {
+    for (size_t i = 0; i < kSize; i++) {
+      mArray[i] = aOther.mArray[i];
+    }
+    return *this;
+  }
+
   typedef typename ArrayType::iterator iterator;
   typedef typename ArrayType::const_iterator const_iterator;
   typedef typename ArrayType::reverse_iterator reverse_iterator;

mfbt/tests/TestEnumeratedArray.cpp

@@ -6,29 +6,41 @@
 
 #include "mozilla/EnumeratedArray.h"
 
+using mozilla::EnumeratedArray;
+
 enum class AnimalSpecies { Cow, Sheep, Pig, Count };
 
+using TestArray = EnumeratedArray<AnimalSpecies, AnimalSpecies::Count, int>;
+
 void TestInitialValueByConstructor() {
-  using namespace mozilla;
   // Style 1
-  EnumeratedArray<AnimalSpecies, AnimalSpecies::Count, int> headCount(1, 2, 3);
+  TestArray headCount(1, 2, 3);
   MOZ_RELEASE_ASSERT(headCount[AnimalSpecies::Cow] == 1);
   MOZ_RELEASE_ASSERT(headCount[AnimalSpecies::Sheep] == 2);
   MOZ_RELEASE_ASSERT(headCount[AnimalSpecies::Pig] == 3);
   // Style 2
-  EnumeratedArray<AnimalSpecies, AnimalSpecies::Count, int> headCount2{5, 6, 7};
+  TestArray headCount2{5, 6, 7};
   MOZ_RELEASE_ASSERT(headCount2[AnimalSpecies::Cow] == 5);
   MOZ_RELEASE_ASSERT(headCount2[AnimalSpecies::Sheep] == 6);
   MOZ_RELEASE_ASSERT(headCount2[AnimalSpecies::Pig] == 7);
   // Style 3
-  EnumeratedArray<AnimalSpecies, AnimalSpecies::Count, int> headCount3(
-      {8, 9, 10});
+  TestArray headCount3({8, 9, 10});
   MOZ_RELEASE_ASSERT(headCount3[AnimalSpecies::Cow] == 8);
   MOZ_RELEASE_ASSERT(headCount3[AnimalSpecies::Sheep] == 9);
   MOZ_RELEASE_ASSERT(headCount3[AnimalSpecies::Pig] == 10);
 }
 
+void TestAssignment() {
+  TestArray headCount{8, 9, 10};
+  TestArray headCount2;
+  headCount2 = headCount;
+  MOZ_RELEASE_ASSERT(headCount2[AnimalSpecies::Cow] == 8);
+  MOZ_RELEASE_ASSERT(headCount2[AnimalSpecies::Sheep] == 9);
+  MOZ_RELEASE_ASSERT(headCount2[AnimalSpecies::Pig] == 10);
+}
+
 int main() {
   TestInitialValueByConstructor();
+  TestAssignment();
   return 0;
-}
+}