| Index: chrome/browser/sync/util/immutable.h
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| diff --git a/chrome/browser/sync/util/immutable.h b/chrome/browser/sync/util/immutable.h
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| deleted file mode 100644
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| index 8bb03c7f3fad41f07cc6fa44621d254d41bc7914..0000000000000000000000000000000000000000
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| --- a/chrome/browser/sync/util/immutable.h
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| +++ /dev/null
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| @@ -1,262 +0,0 @@
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| -// Copyright (c) 2011 The Chromium Authors. All rights reserved.
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| -// Use of this source code is governed by a BSD-style license that can be
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| -// found in the LICENSE file.
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| -
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| -// Immutable<T> provides an easy, cheap, and thread-safe way to pass
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| -// large immutable data around.
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| -//
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| -// For example, consider the following code:
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| -//
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| -//  typedef std::vector<LargeObject> LargeObjectList;
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| -//
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| -//   void ProcessStuff(const LargeObjectList& stuff) {
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| -//     for (LargeObjectList::const_iterator it = stuff.begin();
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| -//          it != stuff.end(); ++it) {
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| -//       ... process it ...
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| -//     }
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| -//   }
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| -//
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| -//   ...
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| -//
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| -//   LargeObjectList my_stuff;
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| -//   ... fill my_stuff with lots of LargeObjects ...
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| -//   some_loop->PostTask(FROM_HERE, base::Bind(&ProcessStuff, my_stuff));
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| -//
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| -// The last line incurs the cost of copying my_stuff, which is
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| -// undesirable.  Here's the above code re-written using Immutable<T>:
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| -//
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| -//   void ProcessStuff(
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| -//       const browser_sync::Immutable<LargeObjectList>& stuff) {
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| -//     for (LargeObjectList::const_iterator it = stuff.Get().begin();
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| -//          it != stuff.Get().end(); ++it) {
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| -//       ... process it ...
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| -//     }
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| -//   }
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| -//
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| -//   ...
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| -//
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| -//   LargeObjectList my_stuff;
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| -//   ... fill my_stuff with lots of LargeObjects ...
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| -//   some_loop->PostTask(
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| -//       FROM_HERE, base::Bind(&ProcessStuff, MakeImmutable(&my_stuff)));
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| -//
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| -// The last line, which resets my_stuff to a default-initialized
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| -// state, incurs only the cost of a swap of LargeObjectLists, which is
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| -// O(1) for most STL container implementations.  The data in my_stuff
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| -// is ref-counted (thread-safely), so it is freed as soon as
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| -// ProcessStuff is finished.
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| -//
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| -// NOTE: By default, Immutable<T> relies on ADL
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| -// (http://en.wikipedia.org/wiki/Argument-dependent_name_lookup) to
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| -// find a swap() function for T, falling back to std::swap() when
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| -// necessary.  If you overload swap() for your type in its namespace,
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| -// or if you specialize std::swap() for your type, (see
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| -// http://stackoverflow.com/questions/11562/how-to-overload-stdswap
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| -// for discussion) Immutable<T> should be able to find it.
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| -//
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| -// Alternatively, you could explicitly control which swap function is
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| -// used by providing your own traits class or using one of the
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| -// pre-defined ones below.  See comments on traits below for details.
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| -//
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| -// NOTE: Some complexity is necessary in order to use Immutable<T>
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| -// with forward-declared types.  See comments on traits below for
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| -// details.
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| -
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| -#ifndef CHROME_BROWSER_SYNC_UTIL_IMMUTABLE_H_
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| -#define CHROME_BROWSER_SYNC_UTIL_IMMUTABLE_H_
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| -#pragma once
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| -
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| -// For std::swap().
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| -#include <algorithm>
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| -
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| -#include "base/basictypes.h"
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| -#include "base/memory/ref_counted.h"
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| -
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| -namespace browser_sync {
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| -
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| -namespace internal {
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| -// This class is part of the Immutable implementation.  DO NOT USE
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| -// THIS CLASS DIRECTLY YOURSELF.
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| -
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| -template <typename T, typename Traits>
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| -class ImmutableCore
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| -    : public base::RefCountedThreadSafe<ImmutableCore<T, Traits> > {
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| - public:
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| -  // wrapper_ is always explicitly default-initialized to handle
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| -  // primitive types and the case where Traits::Wrapper == T.
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| -
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| -  ImmutableCore() : wrapper_() {
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| -    Traits::InitializeWrapper(&wrapper_);
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| -  }
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| -
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| -  explicit ImmutableCore(T* t) : wrapper_() {
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| -    Traits::InitializeWrapper(&wrapper_);
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| -    Traits::Swap(Traits::UnwrapMutable(&wrapper_), t);
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| -  }
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| -
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| -  const T& Get() const {
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| -    return Traits::Unwrap(wrapper_);
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| -  }
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| -
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| - private:
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| -  ~ImmutableCore() {
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| -    Traits::DestroyWrapper(&wrapper_);
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| -  }
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| -  friend class base::RefCountedThreadSafe<ImmutableCore<T, Traits> >;
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| -
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| -  // This is semantically const, but we can't mark it a such as we
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| -  // modify it in the constructor.
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| -  typename Traits::Wrapper wrapper_;
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| -
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| -  DISALLOW_COPY_AND_ASSIGN(ImmutableCore);
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| -};
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| -
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| -}  // namespace internal
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| -
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| -// Traits usage notes
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| -// ------------------
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| -// The most common reason to use your own traits class is to provide
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| -// your own swap method.  First, consider the pre-defined traits
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| -// classes HasSwapMemFn{ByRef,ByPtr} below.  If neither of those work,
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| -// then define your own traits class inheriting from
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| -// DefaultImmutableTraits<YourType> (to pick up the defaults for
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| -// everything else) and provide your own Swap() method.
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| -//
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| -// Another reason to use your own traits class is to be able to use
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| -// Immutable<T> with a forward-declared type (important for protobuf
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| -// classes, when you want to avoid headers pulling in generated
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| -// headers).  (This is why the Traits::Wrapper type exists; normally,
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| -// Traits::Wrapper is just T itself, but that needs to be changed for
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| -// forward-declared types.)
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| -//
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| -// For example, if you want to do this:
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| -//
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| -//   my_class.h
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| -//   ----------
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| -//   #include ".../immutable.h"
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| -//
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| -//   // Forward declaration.
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| -//   class SomeOtherType;
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| -//
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| -//   class MyClass {
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| -//     ...
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| -//    private:
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| -//     // Doesn't work, as defaults traits class needs SomeOtherType's
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| -//     // definition to be visible.
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| -//     Immutable<SomeOtherType> foo_;
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| -//   };
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| -//
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| -// You'll have to do this:
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| -//
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| -//   my_class.h
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| -//   ----------
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| -//   #include ".../immutable.h"
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| -//
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| -//   // Forward declaration.
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| -//   class SomeOtherType;
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| -//
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| -//   class MyClass {
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| -//     ...
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| -//    private:
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| -//     struct ImmutableSomeOtherTypeTraits {
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| -//       // scoped_ptr<SomeOtherType> won't work here, either.
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| -//       typedef SomeOtherType* Wrapper;
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| -//
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| -//       static void InitializeWrapper(Wrapper* wrapper);
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| -//
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| -//       static void DestroyWrapper(Wrapper* wrapper);
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| -//       ...
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| -//     };
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| -//
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| -//     typedef Immutable<SomeOtherType, ImmutableSomeOtherTypeTraits>
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| -//         ImmutableSomeOtherType;
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| -//
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| -//     ImmutableSomeOtherType foo_;
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| -//   };
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| -//
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| -//   my_class.cc
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| -//   -----------
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| -//   #include ".../some_other_type.h"
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| -//
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| -//   void MyClass::ImmutableSomeOtherTypeTraits::InitializeWrapper(
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| -//       Wrapper* wrapper) {
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| -//     *wrapper = new SomeOtherType();
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| -//   }
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| -//
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| -//   void MyClass::ImmutableSomeOtherTypeTraits::DestroyWrapper(
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| -//       Wrapper* wrapper) {
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| -//     delete *wrapper;
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| -//   }
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| -//
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| -//   ...
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| -//
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| -// Also note that this incurs an additional memory allocation when you
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| -// create an Immutable<SomeOtherType>.
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| -
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| -template <typename T>
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| -struct DefaultImmutableTraits {
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| -  typedef T Wrapper;
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| -
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| -  static void InitializeWrapper(Wrapper* wrapper) {}
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| -
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| -  static void DestroyWrapper(Wrapper* wrapper) {}
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| -
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| -  static const T& Unwrap(const Wrapper& wrapper) { return wrapper; }
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| -
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| -  static T* UnwrapMutable(Wrapper* wrapper) { return wrapper; }
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| -
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| -  static void Swap(T* t1, T* t2) {
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| -    // Uses ADL (see
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| -    // http://en.wikipedia.org/wiki/Argument-dependent_name_lookup).
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| -    using std::swap;
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| -    swap(*t1, *t2);
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| -  }
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| -};
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| -
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| -// Most STL containers have by-reference swap() member functions,
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| -// although they usually already overload std::swap() to use those.
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| -template <typename T>
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| -struct HasSwapMemFnByRef : public DefaultImmutableTraits<T> {
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| -  static void Swap(T* t1, T* t2) {
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| -    t1->swap(*t2);
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| -  }
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| -};
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| -
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| -// Most Google-style objects have by-pointer Swap() member functions
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| -// (for example, generated protocol buffer classes).
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| -template <typename T>
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| -struct HasSwapMemFnByPtr : public DefaultImmutableTraits<T> {
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| -  static void Swap(T* t1, T* t2) {
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| -    t1->Swap(t2);
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| -  }
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| -};
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| -
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| -template <typename T, typename Traits = DefaultImmutableTraits<T> >
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| -class Immutable {
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| - public:
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| -  // Puts the underlying object in a default-initialized state.
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| -  Immutable() : core_(new internal::ImmutableCore<T, Traits>()) {}
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| -
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| -  // Copy constructor and assignment welcome.
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| -
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| -  // Resets |t| to a default-initialized state.
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| -  explicit Immutable(T* t)
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| -      : core_(new internal::ImmutableCore<T, Traits>(t)) {}
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| -
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| -  const T& Get() const {
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| -    return core_->Get();
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| -  }
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| -
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| - private:
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| -  scoped_refptr<const internal::ImmutableCore<T, Traits> > core_;
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| -};
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| -
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| -// Helper function to avoid having to write out template arguments.
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| -template <typename T>
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| -Immutable<T> MakeImmutable(T* t) {
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| -  return Immutable<T>(t);
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| -}
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| -
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| -}  // namespace browser_sync
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| -
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| -#endif  // CHROME_BROWSER_SYNC_UTIL_IMMUTABLE_H_
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| 
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