1 files changed, 345 insertions, 0 deletions
diff --git a/xpcom/tests/gtest/TestJSHolderMap.cpp b/xpcom/tests/gtest/TestJSHolderMap.cpp
new file mode 100644
index 0000000000..2255e2e773
--- /dev/null
+++ b/xpcom/tests/gtest/TestJSHolderMap.cpp
@@ -0,0 +1,345 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/CycleCollectedJSRuntime.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/Vector.h"
+
+#include "nsCycleCollectionParticipant.h"
+#include "nsCycleCollector.h"
+
+#include "js/GCAPI.h"
+
+#include "gtest/gtest.h"
+
+using namespace mozilla;
+
+enum HolderKind { SingleZone, MultiZone };
+
+class MyHolder final : public nsScriptObjectTracer {
+ public:
+  explicit MyHolder(HolderKind kind = SingleZone, size_t value = 0)
+      : nsScriptObjectTracer(FlagsForKind(kind)), value(value) {}
+
+  const size_t value;
+
+  NS_IMETHOD_(void) Root(void*) override { MOZ_CRASH(); }
+  NS_IMETHOD_(void) Unlink(void*) override { MOZ_CRASH(); }
+  NS_IMETHOD_(void) Unroot(void*) override { MOZ_CRASH(); }
+  NS_IMETHOD_(void) DeleteCycleCollectable(void*) override { MOZ_CRASH(); }
+  NS_IMETHOD_(void)
+  Trace(void* aPtr, const TraceCallbacks& aCb, void* aClosure) override {
+    MOZ_CRASH();
+  }
+  NS_IMETHOD TraverseNative(void* aPtr,
+                            nsCycleCollectionTraversalCallback& aCb) override {
+    MOZ_CRASH();
+  }
+
+  NS_DECL_CYCLE_COLLECTION_CLASS_NAME_METHOD(MyHolder)
+
+ private:
+  Flags FlagsForKind(HolderKind kind) {
+    return kind == MultiZone ? FlagMultiZoneJSHolder
+                             : FlagMaybeSingleZoneJSHolder;
+  }
+};
+
+static size_t CountEntries(JSHolderMap& map) {
+  size_t count = 0;
+  for (JSHolderMap::Iter i(map); !i.Done(); i.Next()) {
+    MOZ_RELEASE_ASSERT(i->mHolder);
+    MOZ_RELEASE_ASSERT(i->mTracer);
+    count++;
+  }
+  return count;
+}
+
+JS::Zone* DummyZone = reinterpret_cast<JS::Zone*>(1);
+
+JS::Zone* ZoneForKind(HolderKind kind) {
+  return kind == MultiZone ? nullptr : DummyZone;
+}
+
+TEST(JSHolderMap, Empty)
+{
+  JSHolderMap map;
+  ASSERT_EQ(CountEntries(map), 0u);
+}
+
+static void TestAddAndRemove(HolderKind kind) {
+  JSHolderMap map;
+
+  MyHolder holder(kind);
+  nsScriptObjectTracer* tracer = &holder;
+
+  ASSERT_FALSE(map.Has(&holder));
+  ASSERT_EQ(map.Extract(&holder), nullptr);
+
+  map.Put(&holder, tracer, ZoneForKind(kind));
+  ASSERT_TRUE(map.Has(&holder));
+  ASSERT_EQ(CountEntries(map), 1u);
+  ASSERT_EQ(map.Get(&holder), tracer);
+
+  ASSERT_EQ(map.Extract(&holder), tracer);
+  ASSERT_EQ(map.Extract(&holder), nullptr);
+  ASSERT_FALSE(map.Has(&holder));
+  ASSERT_EQ(CountEntries(map), 0u);
+}
+
+TEST(JSHolderMap, AddAndRemove)
+{
+  TestAddAndRemove(SingleZone);
+  TestAddAndRemove(MultiZone);
+}
+
+static void TestIterate(HolderKind kind) {
+  JSHolderMap map;
+
+  MyHolder holder(kind, 0);
+  nsScriptObjectTracer* tracer = &holder;
+
+  Maybe<JSHolderMap::Iter> iter;
+
+  // Iterate an empty map.
+  iter.emplace(map);
+  ASSERT_TRUE(iter->Done());
+  iter.reset();
+
+  // Iterate a map with one entry.
+  map.Put(&holder, tracer, ZoneForKind(kind));
+  iter.emplace(map);
+  ASSERT_FALSE(iter->Done());
+  ASSERT_EQ(iter->Get().mHolder, &holder);
+  iter->Next();
+  ASSERT_TRUE(iter->Done());
+  iter.reset();
+
+  // Iterate a map with 10 entries.
+  constexpr size_t count = 10;
+  Vector<UniquePtr<MyHolder>, 0, InfallibleAllocPolicy> holders;
+  bool seen[count] = {};
+  for (size_t i = 1; i < count; i++) {
+    MOZ_ALWAYS_TRUE(
+        holders.emplaceBack(mozilla::MakeUnique<MyHolder>(kind, i)));
+    map.Put(holders.back().get(), tracer, ZoneForKind(kind));
+  }
+  for (iter.emplace(map); !iter->Done(); iter->Next()) {
+    MyHolder* holder = static_cast<MyHolder*>(iter->Get().mHolder);
+    size_t value = holder->value;
+    ASSERT_TRUE(value < count);
+    ASSERT_FALSE(seen[value]);
+    seen[value] = true;
+  }
+  for (const auto& s : seen) {
+    ASSERT_TRUE(s);
+  }
+}
+
+TEST(JSHolderMap, Iterate)
+{
+  TestIterate(SingleZone);
+  TestIterate(MultiZone);
+}
+
+static void TestAddRemoveMany(HolderKind kind, size_t count) {
+  JSHolderMap map;
+
+  Vector<UniquePtr<MyHolder>, 0, InfallibleAllocPolicy> holders;
+  for (size_t i = 0; i < count; i++) {
+    MOZ_ALWAYS_TRUE(holders.emplaceBack(mozilla::MakeUnique<MyHolder>(kind)));
+  }
+
+  for (size_t i = 0; i < count; i++) {
+    MyHolder* holder = holders[i].get();
+    map.Put(holder, holder, ZoneForKind(kind));
+  }
+
+  ASSERT_EQ(CountEntries(map), count);
+
+  for (size_t i = 0; i < count; i++) {
+    MyHolder* holder = holders[i].get();
+    ASSERT_EQ(map.Extract(holder), holder);
+  }
+
+  ASSERT_EQ(CountEntries(map), 0u);
+}
+
+TEST(JSHolderMap, TestAddRemoveMany)
+{
+  TestAddRemoveMany(SingleZone, 10000);
+  TestAddRemoveMany(MultiZone, 10000);
+}
+
+static void TestRemoveWhileIterating(HolderKind kind, size_t count) {
+  JSHolderMap map;
+  Vector<UniquePtr<MyHolder>, 0, InfallibleAllocPolicy> holders;
+  Maybe<JSHolderMap::Iter> iter;
+
+  for (size_t i = 0; i < count; i++) {
+    MOZ_ALWAYS_TRUE(holders.emplaceBack(MakeUnique<MyHolder>(kind)));
+  }
+
+  // Iterate a map with one entry but remove it before we get to it.
+  MyHolder* holder = holders[0].get();
+  map.Put(holder, holder, ZoneForKind(kind));
+  iter.emplace(map);
+  ASSERT_FALSE(iter->Done());
+  ASSERT_EQ(map.Extract(holder), holder);
+  iter->UpdateForRemovals();
+  ASSERT_TRUE(iter->Done());
+
+  // Check UpdateForRemovals is safe to call on a done iterator.
+  iter->UpdateForRemovals();
+  ASSERT_TRUE(iter->Done());
+  iter.reset();
+
+  // Add many holders and remove them mid way through iteration.
+
+  for (size_t i = 0; i < count; i++) {
+    MyHolder* holder = holders[i].get();
+    map.Put(holder, holder, ZoneForKind(kind));
+  }
+
+  iter.emplace(map);
+  for (size_t i = 0; i < count / 2; i++) {
+    iter->Next();
+    ASSERT_FALSE(iter->Done());
+  }
+
+  for (size_t i = 0; i < count; i++) {
+    MyHolder* holder = holders[i].get();
+    ASSERT_EQ(map.Extract(holder), holder);
+  }
+
+  iter->UpdateForRemovals();
+
+  ASSERT_TRUE(iter->Done());
+  iter.reset();
+
+  ASSERT_EQ(CountEntries(map), 0u);
+}
+
+TEST(JSHolderMap, TestRemoveWhileIterating)
+{
+  TestRemoveWhileIterating(SingleZone, 10000);
+  TestRemoveWhileIterating(MultiZone, 10000);
+}
+
+class ObjectHolder final {
+ public:
+  ObjectHolder() { HoldJSObjects(this); }
+
+  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(ObjectHolder)
+  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(ObjectHolder)
+
+  void SetObject(JSObject* aObject) { mObject = aObject; }
+
+  void ClearObject() { mObject = nullptr; }
+
+  JSObject* GetObject() const { return mObject; }
+  JSObject* GetObjectUnbarriered() const { return mObject.unbarrieredGet(); }
+
+  bool ObjectIsGray() const {
+    JSObject* obj = mObject.unbarrieredGet();
+    MOZ_RELEASE_ASSERT(obj);
+    return JS::GCThingIsMarkedGray(JS::GCCellPtr(obj));
+  }
+
+ private:
+  JS::Heap<JSObject*> mObject;
+
+  ~ObjectHolder() { DropJSObjects(this); }
+};
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(ObjectHolder)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(ObjectHolder)
+  tmp->ClearObject();
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(ObjectHolder)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(ObjectHolder)
+  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mObject)
+NS_IMPL_CYCLE_COLLECTION_TRACE_END
+
+// Test GC things stored in JS holders are marked as gray roots by the GC.
+static void TestHoldersAreMarkedGray(JSContext* cx) {
+  RefPtr holder(new ObjectHolder);
+
+  JSObject* obj = JS_NewPlainObject(cx);
+  ASSERT_TRUE(obj);
+  holder->SetObject(obj);
+  obj = nullptr;
+
+  JS_GC(cx);
+
+  ASSERT_TRUE(holder->ObjectIsGray());
+}
+
+// Test GC things stored in JS holders are updated by compacting GC.
+static void TestHoldersAreMoved(JSContext* cx, bool singleZone) {
+  JS::RootedObject obj(cx, JS_NewPlainObject(cx));
+  ASSERT_TRUE(obj);
+
+  // Set a property so we can check we have the same object at the end.
+  const char* PropertyName = "answer";
+  const int32_t PropertyValue = 42;
+  JS::RootedValue value(cx, JS::Int32Value(PropertyValue));
+  ASSERT_TRUE(JS_SetProperty(cx, obj, PropertyName, value));
+
+  // Ensure the object is tenured.
+  JS_GC(cx);
+
+  RefPtr<ObjectHolder> holder(new ObjectHolder);
+  holder->SetObject(obj);
+
+  uintptr_t original = uintptr_t(obj.get());
+
+  if (singleZone) {
+    JS::PrepareZoneForGC(cx, js::GetContextZone(cx));
+  } else {
+    JS::PrepareForFullGC(cx);
+  }
+
+  JS::NonIncrementalGC(cx, JS::GCOptions::Shrink, JS::GCReason::DEBUG_GC);
+
+  // Shrinking DEBUG_GC should move all GC things.
+  ASSERT_NE(uintptr_t(holder->GetObject()), original);
+
+  // Both root and holder should have been updated.
+  ASSERT_EQ(obj, holder->GetObject());
+
+  // Check it's the object we expect.
+  value.setUndefined();
+  ASSERT_TRUE(JS_GetProperty(cx, obj, PropertyName, &value));
+  ASSERT_EQ(value, JS::Int32Value(PropertyValue));
+}
+
+TEST(JSHolderMap, GCIntegration)
+{
+  CycleCollectedJSContext* ccjscx = CycleCollectedJSContext::Get();
+  ASSERT_NE(ccjscx, nullptr);
+  JSContext* cx = ccjscx->Context();
+  ASSERT_NE(cx, nullptr);
+
+  static const JSClass GlobalClass = {"global", JSCLASS_GLOBAL_FLAGS,
+                                      &JS::DefaultGlobalClassOps};
+
+  JS::RealmOptions options;
+  JS::RootedObject global(cx);
+  global = JS_NewGlobalObject(cx, &GlobalClass, nullptr,
+                              JS::FireOnNewGlobalHook, options);
+  ASSERT_NE(global, nullptr);
+
+  JSAutoRealm ar(cx, global);
+
+  TestHoldersAreMarkedGray(cx);
+  TestHoldersAreMoved(cx, true);
+  TestHoldersAreMoved(cx, false);
+}