Bug 993410 - Improve coverage of nsTArray post barriers test r=terrence

xpcom/glue/tests/gtest/TestGCPostBarriers.cpp

@@ -23,8 +23,7 @@
 using namespace JS;
 using namespace mozilla;
 
-typedef nsTArray<Heap<JSObject*> > ArrayT;
-
+template <class ArrayT>
 static void
 TraceArray(JSTracer* trc, void* data)
 {
@@ -33,19 +32,21 @@ TraceArray(JSTracer* trc, void* data)
     JS_CallHeapObjectTracer(trc, &array->ElementAt(i), "array-element");
 }
 
+/*
+ * Use arrays with initial size much smaller than the final number of elements
+ * to test that moving Heap<T> elements works correctly.
+ */
+const size_t ElementCount = 100;
+const size_t InitialElements = ElementCount / 10;
+
+template <class ArrayT>
 static void
-RunTest(JSRuntime* rt, JSContext* cx)
+RunTest(JSRuntime* rt, JSContext* cx, ArrayT* array)
 {
   JS_GC(rt);
 
-  /*
-   * Create an array with space for half the final number of elements to test
-   * that moving Heap<T> elements works correctly.
-   */
-  const int elements = 100;
-  ArrayT* array = new ArrayT(elements / 2);
   ASSERT_TRUE(array != nullptr);
-  JS_AddExtraGCRootsTracer(rt, TraceArray, array);
+  JS_AddExtraGCRootsTracer(rt, TraceArray<ArrayT>, array);
 
   /*
    * Create the array and fill it with new JS objects. With GGC these will be
@@ -54,7 +55,7 @@ RunTest(JSRuntime* rt, JSContext* cx)
   RootedValue value(cx);
   const char* property = "foo";
   JS::shadow::Runtime* srt = reinterpret_cast<JS::shadow::Runtime*>(rt);
-  for (int i = 0; i < elements; ++i) {
+  for (int i = 0; i < ElementCount; ++i) {
     RootedObject obj(cx, JS_NewObject(cx, nullptr, JS::NullPtr(), JS::NullPtr()));
 #ifdef JSGC_GENERATIONAL
     ASSERT_TRUE(js::gc::IsInsideNursery(srt, obj));
@@ -75,7 +76,7 @@ RunTest(JSRuntime* rt, JSContext* cx)
   /*
    * Sanity check that our array contains what we expect.
    */
-  for (int i = 0; i < elements; ++i) {
+  for (int i = 0; i < ElementCount; ++i) {
     RootedObject obj(cx, array->ElementAt(i));
     ASSERT_FALSE(js::gc::IsInsideNursery(srt, obj));
     ASSERT_TRUE(JS_GetProperty(cx, obj, property, &value));
@@ -83,7 +84,7 @@ RunTest(JSRuntime* rt, JSContext* cx)
     ASSERT_EQ(i, value.toInt32());
   }
 
-  JS_RemoveExtraGCRootsTracer(rt, TraceArray, array);
+  JS_RemoveExtraGCRootsTracer(rt, TraceArray<ArrayT>, array);
 }
 
 static void
@@ -99,17 +100,37 @@ CreateGlobalAndRunTest(JSRuntime* rt, JSContext* cx)
 
   JS::CompartmentOptions options;
   options.setVersion(JSVERSION_LATEST);
-  JS::RootedObject global(cx);
+  JS::PersistentRootedObject global(cx);
   global = JS_NewGlobalObject(cx, &GlobalClass, nullptr, JS::FireOnNewGlobalHook, options);
   ASSERT_TRUE(global != nullptr);
 
-  JS_AddNamedObjectRoot(cx, global.address(), "test-global");
   JSCompartment *oldCompartment = JS_EnterCompartment(cx, global);
 
-  RunTest(rt, cx);
+  typedef Heap<JSObject*> ElementT;
+
+  {
+    nsTArray<ElementT>* array = new nsTArray<ElementT>(InitialElements);
+    RunTest(rt, cx, array);
+    delete array;
+  }
+
+  {
+    FallibleTArray<ElementT>* array = new FallibleTArray<ElementT>(InitialElements);
+    RunTest(rt, cx, array);
+    delete array;
+  }
+
+  {
+    nsAutoTArray<ElementT, InitialElements> array;
+    RunTest(rt, cx, &array);
+  }
+
+  {
+    AutoFallibleTArray<ElementT, InitialElements> array;
+    RunTest(rt, cx, &array);
+  }
 
   JS_LeaveCompartment(cx, oldCompartment);
-  JS_RemoveObjectRoot(cx, global.address());
 }
 
 TEST(GCPostBarriers, nsTArray) {