michael@0: // Copyright (c) 2009 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #ifndef BASE_SCOPED_NSOBJECT_H_
michael@0: #define BASE_SCOPED_NSOBJECT_H_
michael@0: 
michael@0: #import <Foundation/Foundation.h>
michael@0: #include "base/basictypes.h"
michael@0: 
michael@0: // scoped_nsobject<> is patterned after scoped_ptr<>, but maintains ownership
michael@0: // of an NSObject subclass object.  Style deviations here are solely for
michael@0: // compatibility with scoped_ptr<>'s interface, with which everyone is already
michael@0: // familiar.
michael@0: //
michael@0: // When scoped_nsobject<> takes ownership of an object (in the constructor or
michael@0: // in reset()), it takes over the caller's existing ownership claim.  The
michael@0: // caller must own the object it gives to scoped_nsobject<>, and relinquishes
michael@0: // an ownership claim to that object.  scoped_nsobject<> does not call
michael@0: // -retain.
michael@0: template<typename NST>
michael@0: class scoped_nsobject {
michael@0:  public:
michael@0:   typedef NST* element_type;
michael@0: 
michael@0:   explicit scoped_nsobject(NST* object = nil)
michael@0:       : object_(object) {
michael@0:   }
michael@0: 
michael@0:   ~scoped_nsobject() {
michael@0:     [object_ release];
michael@0:   }
michael@0: 
michael@0:   void reset(NST* object = nil) {
michael@0:     [object_ release];
michael@0:     object_ = object;
michael@0:   }
michael@0: 
michael@0:   bool operator==(NST* that) const {
michael@0:     return object_ == that;
michael@0:   }
michael@0: 
michael@0:   bool operator!=(NST* that) const {
michael@0:     return object_ != that;
michael@0:   }
michael@0: 
michael@0:   operator NST*() const {
michael@0:     return object_;
michael@0:   }
michael@0: 
michael@0:   NST* get() const {
michael@0:     return object_;
michael@0:   }
michael@0: 
michael@0:   void swap(scoped_nsobject& that) {
michael@0:     NST* temp = that.object_;
michael@0:     that.object_ = object_;
michael@0:     object_ = temp;
michael@0:   }
michael@0: 
michael@0:   // scoped_nsobject<>::release() is like scoped_ptr<>::release.  It is NOT
michael@0:   // a wrapper for [object_ release].  To force a scoped_nsobject<> object to
michael@0:   // call [object_ release], use scoped_nsobject<>::reset().
michael@0:   NST* release() {
michael@0:     NST* temp = object_;
michael@0:     object_ = nil;
michael@0:     return temp;
michael@0:   }
michael@0: 
michael@0:  private:
michael@0:   NST* object_;
michael@0: 
michael@0:   DISALLOW_COPY_AND_ASSIGN(scoped_nsobject);
michael@0: };
michael@0: 
michael@0: #endif  // BASE_SCOPED_NSOBJECT_H_