scoped_ptr.h | Explore in Territory

// Copyright 2013 Google LLC
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google LLC nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// Scopers help you manage ownership of a pointer, helping you easily manage the
// 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):
//   {
//     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_array):
//   {
//     scoped_array<Foo> foo(new Foo[100]);
//     foo.get()->Method();  // Foo::Method on the 0th element.
//     foo[10].Method();     // Foo::Method on the 10th element.
//   }

#ifndef COMMON_SCOPED_PTR_H_
#define COMMON_SCOPED_PTR_H_

// This is an implementation designed to match the anticipated future TR2
// implementation of the scoped_ptr class, and its closely-related brethren,
// scoped_array, scoped_ptr_malloc.

#include <assert.h>
#include <stddef.h>
#include <stdlib.h>

namespace google_breakpad {

// A scoped_ptr<T> is like a T*, except that the destructor of scoped_ptr<T>
// automatically deletes the pointer it holds (if any).
// That is, scoped_ptr<T> owns the T object that it points to.
// Like a T*, a scoped_ptr<T> may hold either NULL or a pointer to a T object.
// Also like T*, scoped_ptr<T> is thread-compatible, and once you
// dereference it, you get the threadsafety guarantees of T.
//
// The size of a scoped_ptr is small:
// sizeof(scoped_ptr<C>) == sizeof(C*)
template <class C>
class scoped_ptr { … };

// Free functions
template <class C>
void swap(scoped_ptr<C>& p1, scoped_ptr<C>& p2) { … }

template <class C>
bool operator==(C* p1, const scoped_ptr<C>& p2) { … }

template <class C>
bool operator!=(C* p1, const scoped_ptr<C>& p2) { … }

// scoped_array<C> is like scoped_ptr<C>, except that the caller must allocate
// with new [] and the destructor deletes objects with delete [].
//
// As with scoped_ptr<C>, a scoped_array<C> either points to an object
// or is NULL.  A scoped_array<C> owns the object that it points to.
// scoped_array<T> is thread-compatible, and once you index into it,
// the returned objects have only the threadsafety guarantees of T.
//
// Size: sizeof(scoped_array<C>) == sizeof(C*)
template <class C>
class scoped_array { … };

// Free functions
template <class C>
void swap(scoped_array<C>& p1, scoped_array<C>& p2) { … }

template <class C>
bool operator==(C* p1, const scoped_array<C>& p2) { … }

template <class C>
bool operator!=(C* p1, const scoped_array<C>& p2) { … }

// This class wraps the c library function free() in a class that can be
// passed as a template argument to scoped_ptr_malloc below.
class ScopedPtrMallocFree { … };

// scoped_ptr_malloc<> is similar to scoped_ptr<>, but it accepts a
// second template argument, the functor used to free the object.

template<class C, class FreeProc = ScopedPtrMallocFree>
class scoped_ptr_malloc { … };

template<class C, class FP> inline
void swap(scoped_ptr_malloc<C, FP>& a, scoped_ptr_malloc<C, FP>& b) { … }

template<class C, class FP> inline
bool operator==(C* p, const scoped_ptr_malloc<C, FP>& b) { … }

template<class C, class FP> inline
bool operator!=(C* p, const scoped_ptr_malloc<C, FP>& b) { … }

}  // namespace google_breakpad

#endif  // COMMON_SCOPED_PTR_H_
chromium/third_party/breakpad/breakpad/src/common/scoped_ptr.h
