1 // Copyright 2015 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef TRACEIMPL_OMITTED_TRACE_H_
6 #define TRACEIMPL_OMITTED_TRACE_H_
7 
8 #include "heap/stubs.h"
9 
10 namespace blink {
11 
12 class A : public GarbageCollected<A> {
13  public:
trace(Visitor * visitor)14   virtual void trace(Visitor* visitor) { traceImpl(visitor); }
trace(InlinedGlobalMarkingVisitor visitor)15   virtual void trace(InlinedGlobalMarkingVisitor visitor) {
16     traceImpl(visitor);
17   }
18 
19  private:
20   template <typename VisitorDispatcher>
traceImpl(VisitorDispatcher visitor)21   void traceImpl(VisitorDispatcher visitor) {}
22 };
23 
24 class B : public A {
25   // trace() isn't necessary because we've got nothing to trace here.
26 };
27 
28 class C : public B {
29  public:
trace(Visitor * visitor)30   void trace(Visitor* visitor) override { traceImpl(visitor); }
trace(InlinedGlobalMarkingVisitor visitor)31   void trace(InlinedGlobalMarkingVisitor visitor) override {
32     traceImpl(visitor);
33   }
34 
35  private:
36   template <typename VisitorDispatcher>
traceImpl(VisitorDispatcher visitor)37   void traceImpl(VisitorDispatcher visitor) {
38     // B::trace() is actually A::trace(), and in certain cases we only get
39     // limited information like "there is a function call that will be resolved
40     // to A::trace()". We still want to mark B as traced.
41     B::trace(visitor);
42   }
43 };
44 
45 }
46 
47 #endif  // TRACEIMPL_OMITTED_TRACE_H_
48