Move files in wtf/ to platform/wtf/ (Part 8).

third_party/WebKit/Source/wtf/VectorTraits.h

Index: third_party/WebKit/Source/wtf/VectorTraits.h
diff --git a/third_party/WebKit/Source/wtf/VectorTraits.h b/third_party/WebKit/Source/wtf/VectorTraits.h
index b721f4622d267b203c6b45c18fed686488e50762..eadd393cd9df8f58d15cd7d89e265d247c6bdd27 100644
--- a/third_party/WebKit/Source/wtf/VectorTraits.h
+++ b/third_party/WebKit/Source/wtf/VectorTraits.h
@@ -1,186 +1,9 @@
-/*
- * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public License
- * along with this library; see the file COPYING.LIB.  If not, write to
- * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- * Boston, MA 02110-1301, USA.
- *
- */
+// Copyright 2017 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 WTF_VectorTraits_h
-#define WTF_VectorTraits_h
+#include "platform/wtf/VectorTraits.h"
 
-#include "wtf/RefPtr.h"
-#include "wtf/TypeTraits.h"
-#include <memory>
-#include <type_traits>
-#include <utility>
-
-namespace WTF {
-
-template <typename T>
-struct VectorTraitsBase {
-  static const bool needsDestruction = !IsTriviallyDestructible<T>::value;
-
-  static const bool canInitializeWithMemset =
-      IsTriviallyDefaultConstructible<T>::value;
-  // true iff memset(slot, 0, size) constructs an unused slot value that is
-  // valid for Oilpan to trace and if the value needs destruction, its
-  // destructor can be invoked over. The zero'ed value representing an unused
-  // slot in the vector's backing storage; it does not have to be equal to
-  // what its constructor(s) would create, only be valid for those two uses.
-  static const bool canClearUnusedSlotsWithMemset =
-      IsTriviallyDefaultConstructible<T>::value;
-
-  static const bool canMoveWithMemcpy = IsTriviallyMoveAssignable<T>::value;
-  static const bool canCopyWithMemcpy = IsTriviallyCopyAssignable<T>::value;
-  static const bool canFillWithMemset =
-      IsTriviallyDefaultConstructible<T>::value && (sizeof(T) == sizeof(char));
-  static const bool canCompareWithMemcmp =
-      std::is_scalar<T>::value;  // Types without padding.
-
-  // Supports swapping elements using regular std::swap semantics.
-  static const bool canSwapUsingCopyOrMove = true;
-
-  template <typename U = void>
-  struct IsTraceableInCollection {
-    static const bool value = IsTraceable<T>::value;
-  };
-  // We don't support weak handling in vectors.
-  static const WeakHandlingFlag weakHandlingFlag = NoWeakHandlingInCollections;
-};
-
-template <typename T>
-struct VectorTraits : VectorTraitsBase<T> {};
-
-// Classes marked with SimpleVectorTraits will use memmov, memcpy, memcmp
-// instead of constructors, copy operators, etc for initialization, move and
-// comparison.
-template <typename T>
-struct SimpleClassVectorTraits : VectorTraitsBase<T> {
-  static const bool canInitializeWithMemset = true;
-  static const bool canClearUnusedSlotsWithMemset = true;
-  static const bool canMoveWithMemcpy = true;
-  static const bool canCompareWithMemcmp = true;
-};
-
-// We know std::unique_ptr and RefPtr are simple enough that initializing to 0
-// and moving with memcpy (and then not destructing the original) will totally
-// work.
-template <typename P>
-struct VectorTraits<RefPtr<P>> : SimpleClassVectorTraits<RefPtr<P>> {};
-
-template <typename P>
-struct VectorTraits<std::unique_ptr<P>>
-    : SimpleClassVectorTraits<std::unique_ptr<P>> {
-  // std::unique_ptr -> std::unique_ptr has a very particular structure that
-  // tricks the normal type traits into thinking that the class is "trivially
-  // copyable".
-  static const bool canCopyWithMemcpy = false;
-};
-static_assert(VectorTraits<RefPtr<int>>::canInitializeWithMemset,
-              "inefficient RefPtr Vector");
-static_assert(VectorTraits<RefPtr<int>>::canMoveWithMemcpy,
-              "inefficient RefPtr Vector");
-static_assert(VectorTraits<RefPtr<int>>::canCompareWithMemcmp,
-              "inefficient RefPtr Vector");
-static_assert(VectorTraits<std::unique_ptr<int>>::canInitializeWithMemset,
-              "inefficient std::unique_ptr Vector");
-static_assert(VectorTraits<std::unique_ptr<int>>::canMoveWithMemcpy,
-              "inefficient std::unique_ptr Vector");
-static_assert(VectorTraits<std::unique_ptr<int>>::canCompareWithMemcmp,
-              "inefficient std::unique_ptr Vector");
-
-template <typename First, typename Second>
-struct VectorTraits<std::pair<First, Second>> {
-  typedef VectorTraits<First> FirstTraits;
-  typedef VectorTraits<Second> SecondTraits;
-
-  static const bool needsDestruction =
-      FirstTraits::needsDestruction || SecondTraits::needsDestruction;
-  static const bool canInitializeWithMemset =
-      FirstTraits::canInitializeWithMemset &&
-      SecondTraits::canInitializeWithMemset;
-  static const bool canMoveWithMemcpy =
-      FirstTraits::canMoveWithMemcpy && SecondTraits::canMoveWithMemcpy;
-  static const bool canCopyWithMemcpy =
-      FirstTraits::canCopyWithMemcpy && SecondTraits::canCopyWithMemcpy;
-  static const bool canFillWithMemset = false;
-  static const bool canCompareWithMemcmp =
-      FirstTraits::canCompareWithMemcmp && SecondTraits::canCompareWithMemcmp;
-  static const bool canClearUnusedSlotsWithMemset =
-      FirstTraits::canClearUnusedSlotsWithMemset &&
-      SecondTraits::canClearUnusedSlotsWithMemset;
-  // Supports swapping elements using regular std::swap semantics.
-  static const bool canSwapUsingCopyOrMove = true;
-  template <typename U = void>
-  struct IsTraceableInCollection {
-    static const bool value =
-        IsTraceableInCollectionTrait<FirstTraits>::value ||
-        IsTraceableInCollectionTrait<SecondTraits>::value;
-  };
-  // We don't support weak handling in vectors.
-  static const WeakHandlingFlag weakHandlingFlag = NoWeakHandlingInCollections;
-};
-
-}  // namespace WTF
-
-#define WTF_ALLOW_MOVE_INIT_AND_COMPARE_WITH_MEM_FUNCTIONS(ClassName)     \
-  namespace WTF {                                                         \
-  static_assert(!IsTriviallyDefaultConstructible<ClassName>::value ||     \
-                    !IsTriviallyMoveAssignable<ClassName>::value ||       \
-                    !std::is_scalar<ClassName>::value,                    \
-                "macro not needed");                                      \
-  template <>                                                             \
-  struct VectorTraits<ClassName> : SimpleClassVectorTraits<ClassName> {}; \
-  }
-
-#define WTF_ALLOW_MOVE_AND_INIT_WITH_MEM_FUNCTIONS(ClassName)         \
-  namespace WTF {                                                     \
-  static_assert(!IsTriviallyDefaultConstructible<ClassName>::value || \
-                    !IsTriviallyMoveAssignable<ClassName>::value,     \
-                "macro not needed");                                  \
-  template <>                                                         \
-  struct VectorTraits<ClassName> : VectorTraitsBase<ClassName> {      \
-    static const bool canInitializeWithMemset = true;                 \
-    static const bool canClearUnusedSlotsWithMemset = true;           \
-    static const bool canMoveWithMemcpy = true;                       \
-  };                                                                  \
-  }
-
-#define WTF_ALLOW_INIT_WITH_MEM_FUNCTIONS(ClassName)                \
-  namespace WTF {                                                   \
-  static_assert(!IsTriviallyDefaultConstructible<ClassName>::value, \
-                "macro not needed");                                \
-  template <>                                                       \
-  struct VectorTraits<ClassName> : VectorTraitsBase<ClassName> {    \
-    static const bool canInitializeWithMemset = true;               \
-    static const bool canClearUnusedSlotsWithMemset = true;         \
-  };                                                                \
-  }
-
-#define WTF_ALLOW_CLEAR_UNUSED_SLOTS_WITH_MEM_FUNCTIONS(ClassName)  \
-  namespace WTF {                                                   \
-  static_assert(!IsTriviallyDefaultConstructible<ClassName>::value, \
-                "macro not needed");                                \
-  template <>                                                       \
-  struct VectorTraits<ClassName> : VectorTraitsBase<ClassName> {    \
-    static const bool canClearUnusedSlotsWithMemset = true;         \
-  };                                                                \
-  }
-
-using WTF::VectorTraits;
-using WTF::SimpleClassVectorTraits;
-
-#endif  // WTF_VectorTraits_h
+// The contents of this header was moved to platform/wtf as part of
+// WTF migration project. See the following post for details:
+// https://groups.google.com/a/chromium.org/d/msg/blink-dev/tLdAZCTlcAA/bYXVT8gYCAAJ