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+// Copyright (c) 2012 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.
+
+// Scopers help you manage ownership of a pointer, helping you easily manage a
+// pointer within a scope, and automatically destroying the pointer at the end
+// of a scope. There are two main classes you will use, which correspond to the
+// operators new/delete and new[]/delete[].
+//
+// Example usage (scoped_ptr<T>):
+// {
+// scoped_ptr<Foo> foo(new Foo("wee"));
+// } // foo goes out of scope, releasing the pointer with it.
+//
+// {
+// scoped_ptr<Foo> foo; // No pointer managed.
+// foo.reset(new Foo("wee")); // Now a pointer is managed.
+// foo.reset(new Foo("wee2")); // Foo("wee") was destroyed.
+// foo.reset(new Foo("wee3")); // Foo("wee2") was destroyed.
+// foo->Method(); // Foo::Method() called.
+// foo.get()->Method(); // Foo::Method() called.
+// SomeFunc(foo.release()); // SomeFunc takes ownership, foo no longer
+// // manages a pointer.
+// foo.reset(new Foo("wee4")); // foo manages a pointer again.
+// foo.reset(); // Foo("wee4") destroyed, foo no longer
+// // manages a pointer.
+// } // foo wasn't managing a pointer, so nothing was destroyed.
+//
+// Example usage (scoped_ptr<T[]>):
+// {
+// scoped_ptr<Foo[]> foo(new Foo[100]);
+// foo.get()->Method(); // Foo::Method on the 0th element.
+// foo[10].Method(); // Foo::Method on the 10th element.
+// }
+//
+// Scopers are testable as booleans:
+// {
+// scoped_ptr<Foo> foo;
+// if (!foo)
+// foo.reset(new Foo());
+// if (foo)
+// LOG(INFO) << "This code is reached."
+// }
+//
+// These scopers also implement part of the functionality of C++11 unique_ptr
+// in that they are "movable but not copyable." You can use the scopers in
+// the parameter and return types of functions to signify ownership transfer
+// in to and out of a function. When calling a function that has a scoper
+// as the argument type, it must be called with an rvalue of a scoper, which
+// can be created by using std::move(), or the result of another function that
+// generates a temporary; passing by copy will NOT work. Here is an example
+// using scoped_ptr:
+//
+// void TakesOwnership(scoped_ptr<Foo> arg) {
+// // Do something with arg.
+// }
+// scoped_ptr<Foo> CreateFoo() {
+// // No need for calling std::move() for returning a move-only value, or
+// // when you already have an rvalue as we do here.
+// return scoped_ptr<Foo>(new Foo("new"));
+// }
+// scoped_ptr<Foo> PassThru(scoped_ptr<Foo> arg) {
+// return arg;
+// }
+//
+// {
+// scoped_ptr<Foo> ptr(new Foo("yay")); // ptr manages Foo("yay").
+// TakesOwnership(std::move(ptr)); // ptr no longer owns Foo("yay").
+// scoped_ptr<Foo> ptr2 = CreateFoo(); // ptr2 owns the return Foo.
+// scoped_ptr<Foo> ptr3 = // ptr3 now owns what was in ptr2.
+// PassThru(std::move(ptr2)); // ptr2 is correspondingly nullptr.
+// }
+//
+// Notice that if you do not call std::move() when returning from PassThru(), or
+// when invoking TakesOwnership(), the code will not compile because scopers
+// are not copyable; they only implement move semantics which require calling
+// the std::move() function to signify a destructive transfer of state.
+// CreateFoo() is different though because we are constructing a temporary on
+// the return line and thus can avoid needing to call std::move().
+//
+// The conversion move-constructor properly handles upcast in initialization,
+// i.e. you can use a scoped_ptr<Child> to initialize a scoped_ptr<Parent>:
+//
+// scoped_ptr<Foo> foo(new Foo());
+// scoped_ptr<FooParent> parent(std::move(foo));
+
+#ifndef BASE_MEMORY_SCOPED_PTR_H_
+#define BASE_MEMORY_SCOPED_PTR_H_
+
+// This is an implementation designed to match the anticipated future TR2
+// implementation of the scoped_ptr class.
+
+// TODO(dcheng): Clean up these headers, but there are likely lots of existing
+// IWYU violations.
+#include <stddef.h>
+#include <stdlib.h>
+
+#include <iosfwd>
+#include <memory>
+#include <type_traits>
+#include <utility>
+
+#include "base/compiler_specific.h"
+#include "base/logging.h"
+#include "base/macros.h"
+#include "base/move.h"
+#include "build/build_config.h"
+
+namespace base {
+
+// Function object which invokes 'free' on its parameter, which must be
+// a pointer. Can be used to store malloc-allocated pointers in scoped_ptr:
+//
+// scoped_ptr<int, base::FreeDeleter> foo_ptr(
+// static_cast<int*>(malloc(sizeof(int))));
+struct FreeDeleter {
+ inline void operator()(void* ptr) const {
+ free(ptr);
+ }
+};
+
+} // namespace base
+
+template <typename T, typename D = std::default_delete<T>>
+using scoped_ptr = std::unique_ptr<T, D>;
+
+// A function to convert T* into scoped_ptr<T>
+// Doing e.g. make_scoped_ptr(new FooBarBaz<type>(arg)) is a shorter notation
+// for scoped_ptr<FooBarBaz<type> >(new FooBarBaz<type>(arg))
+template <typename T>
+scoped_ptr<T> make_scoped_ptr(T* ptr) {
+ return scoped_ptr<T>(ptr);
+}
+
+#endif // BASE_MEMORY_SCOPED_PTR_H_