scoped_nsobject.h - mozsearch

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

// Copyright (c) 2009 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_SCOPED_NSOBJECT_H_

#define BASE_SCOPED_NSOBJECT_H_

#import <Foundation/Foundation.h>

#include "base/basictypes.h"

// scoped_nsobject<> is patterned after scoped_ptr<>, but maintains ownership

// of an NSObject subclass object.  Style deviations here are solely for

// compatibility with scoped_ptr<>'s interface, with which everyone is already

// familiar.

//

// When scoped_nsobject<> takes ownership of an object (in the constructor or

// in reset()), it takes over the caller's existing ownership claim.  The

// caller must own the object it gives to scoped_nsobject<>, and relinquishes

// an ownership claim to that object.  scoped_nsobject<> does not call

// -retain.

template <typename NST>

class scoped_nsobject {

 public:

  typedef NST* element_type;

  explicit scoped_nsobject(NST* object = nil) : object_(object) {}

  ~scoped_nsobject() { [object_ release]; }

  void reset(NST* object = nil) {

    [object_ release];

    object_ = object;

  bool operator==(NST* that) const { return object_ == that; }

  bool operator!=(NST* that) const { return object_ != that; }

  operator NST*() const { return object_; }

  NST* get() const { return object_; }

  void swap(scoped_nsobject& that) {

    NST* temp = that.object_;

    that.object_ = object_;

    object_ = temp;

  // scoped_nsobject<>::release() is like scoped_ptr<>::release.  It is NOT

  // a wrapper for [object_ release].  To force a scoped_nsobject<> object to

  // call [object_ release], use scoped_nsobject<>::reset().

  NST* release() {

    NST* temp = object_;

    object_ = nil;

    return temp;

 private:

  NST* object_;

  DISALLOW_COPY_AND_ASSIGN(scoped_nsobject);

};

#endif  // BASE_SCOPED_NSOBJECT_H_