Tries to catch callbacks expecting scoped_refptr<T> and getting T* using template magic

Review URL: http://codereview.chromium.org/414024

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@33531 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 170 insertions, 0 deletions

diff --git a/base/raw_scoped_refptr_mismatch_checker.h b/base/raw_scoped_refptr_mismatch_checker.h
new file mode 100644
index 0000000..598710f
--- /dev/null
+++ b/base/raw_scoped_refptr_mismatch_checker.h
@@ -0,0 +1,170 @@
+// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_
+#define BASE_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_
+
+#include "base/ref_counted.h"
+#include "base/tuple.h"
+
+// It is dangerous to post a task with a raw pointer argument to a function
+// that expects a scoped_refptr<>.  The compiler will happily accept the
+// situation, but it will not attempt to increase the refcount until the task
+// runs.  Callers expecting the argument to be refcounted up at post time are
+// in for a nasty surprise!  Example: http://crbug.com/27191
+// The following set of traits are designed to generate a compile error
+// whenever this antipattern is attempted.
+template <class A, class B>
+struct ExpectsScopedRefptrButGetsRawPtr {
+  enum { value = 0 };
+};
+
+template <class A, class B>
+struct ExpectsScopedRefptrButGetsRawPtr<scoped_refptr<A>, B*> {
+  enum { value = 1 };
+};
+
+template <class Function, class Params>
+struct FunctionUsesScopedRefptrCorrectly {
+  enum { value = 1 };
+};
+
+template <class A1, class A2>
+struct FunctionUsesScopedRefptrCorrectly<void (*)(A1), Tuple1<A2> > {
+  enum { value = !ExpectsScopedRefptrButGetsRawPtr<A1, A2>::value };
+};
+
+template <class A1, class B1, class A2, class B2>
+struct FunctionUsesScopedRefptrCorrectly<void (*)(A1, B1), Tuple2<A2, B2> > {
+  enum { value = !(ExpectsScopedRefptrButGetsRawPtr<A1, A2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<B1, B2>::value) };
+};
+
+template <class A1, class B1, class C1, class A2, class B2, class C2>
+struct FunctionUsesScopedRefptrCorrectly<void (*)(A1, B1, C1),
+                                         Tuple3<A2, B2, C2> > {
+  enum { value = !(ExpectsScopedRefptrButGetsRawPtr<A1, A2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<B1, B2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<C1, C2>::value) };
+};
+
+template <class A1, class B1, class C1, class D1,
+          class A2, class B2, class C2, class D2>
+struct FunctionUsesScopedRefptrCorrectly<void (*)(A1, B1, C1, D1),
+                                         Tuple4<A2, B2, C2, D2> > {
+  enum { value = !(ExpectsScopedRefptrButGetsRawPtr<A1, A2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<B1, B2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<C1, C2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<D1, D2>::value) };
+};
+
+template <class A1, class B1, class C1, class D1, class E1,
+          class A2, class B2, class C2, class D2, class E2>
+struct FunctionUsesScopedRefptrCorrectly<void (*)(A1, B1, C1, D1, E1),
+                                         Tuple5<A2, B2, C2, D2, E2> > {
+  enum { value = !(ExpectsScopedRefptrButGetsRawPtr<A1, A2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<B1, B2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<C1, C2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<D1, D2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<E1, E2>::value) };
+};
+
+template <class A1, class B1, class C1, class D1, class E1, class F1,
+          class A2, class B2, class C2, class D2, class E2, class F2>
+struct FunctionUsesScopedRefptrCorrectly<void (*)(A1, B1, C1, D1, E1, F1),
+                                         Tuple6<A2, B2, C2, D2, E2, F2> > {
+  enum { value = !(ExpectsScopedRefptrButGetsRawPtr<A1, A2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<B1, B2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<C1, C2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<D1, D2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<E1, E2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<F1, F2>::value) };
+};
+
+template <class A1, class B1, class C1, class D1, class E1, class F1, class G1,
+          class A2, class B2, class C2, class D2, class E2, class F2, class G2>
+struct FunctionUsesScopedRefptrCorrectly<void (*)(A1, B1, C1, D1, E1, F1, G1),
+                                         Tuple7<A2, B2, C2, D2, E2, F2, G2> > {
+  enum { value = !(ExpectsScopedRefptrButGetsRawPtr<A1, A2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<B1, B2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<C1, C2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<D1, D2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<E1, E2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<F1, F2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<G1, G2>::value) };
+};
+
+template <class Method, class Params>
+struct MethodUsesScopedRefptrCorrectly {
+  enum { value = 1 };
+};
+
+template <class T, class A1, class A2>
+struct MethodUsesScopedRefptrCorrectly<void (T::*)(A1), Tuple1<A2> > {
+  enum { value = !ExpectsScopedRefptrButGetsRawPtr<A1, A2>::value };
+};
+
+template <class T, class A1, class B1, class A2, class B2>
+struct MethodUsesScopedRefptrCorrectly<void (T::*)(A1, B1), Tuple2<A2, B2> > {
+  enum { value = !(ExpectsScopedRefptrButGetsRawPtr<A1, A2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<B1, B2>::value) };
+};
+
+template <class T, class A1, class B1, class C1,
+                   class A2, class B2, class C2>
+struct MethodUsesScopedRefptrCorrectly<void (T::*)(A1, B1, C1),
+                                       Tuple3<A2, B2, C2> > {
+  enum { value = !(ExpectsScopedRefptrButGetsRawPtr<A1, A2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<B1, B2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<C1, C2>::value) };
+};
+
+template <class T, class A1, class B1, class C1, class D1,
+          class A2, class B2, class C2, class D2>
+struct MethodUsesScopedRefptrCorrectly<void (T::*)(A1, B1, C1, D1),
+                                       Tuple4<A2, B2, C2, D2> > {
+  enum { value = !(ExpectsScopedRefptrButGetsRawPtr<A1, A2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<B1, B2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<C1, C2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<D1, D2>::value) };
+};
+
+template <class T, class A1, class B1, class C1, class D1, class E1,
+                   class A2, class B2, class C2, class D2, class E2>
+struct MethodUsesScopedRefptrCorrectly<void (T::*)(A1, B1, C1, D1, E1),
+                                       Tuple5<A2, B2, C2, D2, E2> > {
+  enum { value = !(ExpectsScopedRefptrButGetsRawPtr<A1, A2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<B1, B2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<C1, C2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<D1, D2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<E1, E2>::value) };
+};
+
+template <class T, class A1, class B1, class C1, class D1, class E1, class F1,
+                   class A2, class B2, class C2, class D2, class E2, class F2>
+struct MethodUsesScopedRefptrCorrectly<void (T::*)(A1, B1, C1, D1, E1, F1),
+                                       Tuple6<A2, B2, C2, D2, E2, F2> > {
+  enum { value = !(ExpectsScopedRefptrButGetsRawPtr<A1, A2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<B1, B2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<C1, C2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<D1, D2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<E1, E2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<F1, F2>::value) };
+};
+
+template <class T,
+          class A1, class B1, class C1, class D1, class E1, class F1, class G1,
+          class A2, class B2, class C2, class D2, class E2, class F2, class G2>
+struct MethodUsesScopedRefptrCorrectly<void (T::*)(A1, B1, C1, D1, E1, F1, G1),
+                                       Tuple7<A2, B2, C2, D2, E2, F2, G2> > {
+  enum { value = !(ExpectsScopedRefptrButGetsRawPtr<A1, A2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<B1, B2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<C1, C2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<D1, D2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<E1, E2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<F1, F2>::value ||
+                   ExpectsScopedRefptrButGetsRawPtr<G1, G2>::value) };
+};
+
+#endif  // BASE_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_