Bug 1648044 - Add Maybe<T&>::refEquals methods. r=froydnj

Differential Revision: https://phabricator.services.mozilla.com/D80845

mfbt/Maybe.h

@@ -744,6 +744,12 @@ class Maybe<T&> {
     return val;
   }
 
+  bool refEquals(const Maybe<T&>& aOther) const {
+    return mValue == aOther.mValue;
+  }
+
+  bool refEquals(const T& aOther) const { return mValue == &aOther; }
+
  private:
   T* mValue = nullptr;
 };

mfbt/tests/TestMaybe.cpp

@@ -1265,7 +1265,7 @@ static bool TestReference() {
   }
 
   {
-    int foo = 42;
+    int foo = 42, bar = 42;
     Maybe<int&> some = SomeRef(foo);
 
     MOZ_RELEASE_ASSERT(!some.isNothing());
@@ -1273,6 +1273,12 @@ static bool TestReference() {
     MOZ_RELEASE_ASSERT(some);
     MOZ_RELEASE_ASSERT(&some.ref() == &foo);
 
+    MOZ_RELEASE_ASSERT(some.refEquals(foo));
+    MOZ_RELEASE_ASSERT(some.refEquals(SomeRef(foo)));
+    MOZ_RELEASE_ASSERT(!some.refEquals(Nothing()));
+    MOZ_RELEASE_ASSERT(!some.refEquals(bar));
+    MOZ_RELEASE_ASSERT(!some.refEquals(SomeRef(bar)));
+
     some.ref()++;
     MOZ_RELEASE_ASSERT(43 == foo);
 
@@ -1281,7 +1287,7 @@ static bool TestReference() {
   }
 
   {
-    int foo = 42;
+    int foo = 42, bar = 42;
     Maybe<int&> some;
     some.emplace(foo);
 
@@ -1290,6 +1296,12 @@ static bool TestReference() {
     MOZ_RELEASE_ASSERT(some);
     MOZ_RELEASE_ASSERT(&some.ref() == &foo);
 
+    MOZ_RELEASE_ASSERT(some.refEquals(foo));
+    MOZ_RELEASE_ASSERT(some.refEquals(SomeRef(foo)));
+    MOZ_RELEASE_ASSERT(!some.refEquals(Nothing()));
+    MOZ_RELEASE_ASSERT(!some.refEquals(bar));
+    MOZ_RELEASE_ASSERT(!some.refEquals(SomeRef(bar)));
+
     some.ref()++;
     MOZ_RELEASE_ASSERT(43 == foo);
   }