The Tor Browser: comparison security/sandbox/chromium/base/memory/ref

--1:000000000000
+:2fc76879c354
+// 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.
+#ifndef BASE_MEMORY_REF_COUNTED_H_
+#define BASE_MEMORY_REF_COUNTED_H_
+#include <cassert>
+#include "base/atomic_ref_count.h"
+#include "base/base_export.h"
+#include "base/compiler_specific.h"
+#include "base/threading/thread_collision_warner.h"
+namespace base {
+namespace subtle {
+class BASE_EXPORT RefCountedBase {
+public:
+bool HasOneRef() const { return ref_count_ == 1; }
+protected:
+RefCountedBase();
+~RefCountedBase();
+void AddRef() const;
+// Returns true if the object should self-delete.
+bool Release() const;
+private:
+mutable int ref_count_;
+#ifndef NDEBUG
+mutable bool in_dtor_;
+#endif
+DFAKE_MUTEX(add_release_);
+DISALLOW_COPY_AND_ASSIGN(RefCountedBase);
+};
+class BASE_EXPORT RefCountedThreadSafeBase {
+public:
+bool HasOneRef() const;
+protected:
+RefCountedThreadSafeBase();
+~RefCountedThreadSafeBase();
+void AddRef() const;
+// Returns true if the object should self-delete.
+bool Release() const;
+private:
+mutable AtomicRefCount ref_count_;
+#ifndef NDEBUG
+mutable bool in_dtor_;
+#endif
+DISALLOW_COPY_AND_ASSIGN(RefCountedThreadSafeBase);
+};
+}  // namespace subtle
+//
+// A base class for reference counted classes.  Otherwise, known as a cheap
+// knock-off of WebKit's RefCounted<T> class.  To use this guy just extend your
+// class from it like so:
+//
+//   class MyFoo : public base::RefCounted<MyFoo> {
+//    ...
+//    private:
+//     friend class base::RefCounted<MyFoo>;
+//     ~MyFoo();
+//   };
+//
+// You should always make your destructor private, to avoid any code deleting
+// the object accidently while there are references to it.
+template <class T>
+class RefCounted : public subtle::RefCountedBase {
+public:
+RefCounted() {}
+void AddRef() const {
+subtle::RefCountedBase::AddRef();
+}
+void Release() const {
+if (subtle::RefCountedBase::Release()) {
+delete static_cast<const T*>(this);
+}
+}
+protected:
+~RefCounted() {}
+private:
+DISALLOW_COPY_AND_ASSIGN(RefCounted<T>);
+};
+// Forward declaration.
+template <class T, typename Traits> class RefCountedThreadSafe;
+// Default traits for RefCountedThreadSafe<T>.  Deletes the object when its ref
+// count reaches 0.  Overload to delete it on a different thread etc.
+template<typename T>
+struct DefaultRefCountedThreadSafeTraits {
+static void Destruct(const T* x) {
+// Delete through RefCountedThreadSafe to make child classes only need to be
+// friend with RefCountedThreadSafe instead of this struct, which is an
+// implementation detail.
+RefCountedThreadSafe<T,
+DefaultRefCountedThreadSafeTraits>::DeleteInternal(x);
+}
+};
+//
+// A thread-safe variant of RefCounted<T>
+//
+//   class MyFoo : public base::RefCountedThreadSafe<MyFoo> {
+//    ...
+//   };
+//
+// If you're using the default trait, then you should add compile time
+// asserts that no one else is deleting your object.  i.e.
+//    private:
+//     friend class base::RefCountedThreadSafe<MyFoo>;
+//     ~MyFoo();
+template <class T, typename Traits = DefaultRefCountedThreadSafeTraits<T> >
+class RefCountedThreadSafe : public subtle::RefCountedThreadSafeBase {
+public:
+RefCountedThreadSafe() {}
+void AddRef() const {
+subtle::RefCountedThreadSafeBase::AddRef();
+}
+void Release() const {
+if (subtle::RefCountedThreadSafeBase::Release()) {
+Traits::Destruct(static_cast<const T*>(this));
+}
+}
+protected:
+~RefCountedThreadSafe() {}
+private:
+friend struct DefaultRefCountedThreadSafeTraits<T>;
+static void DeleteInternal(const T* x) { delete x; }
+DISALLOW_COPY_AND_ASSIGN(RefCountedThreadSafe);
+};
+//
+// A thread-safe wrapper for some piece of data so we can place other
+// things in scoped_refptrs<>.
+//
+template<typename T>
+class RefCountedData
+: public base::RefCountedThreadSafe< base::RefCountedData<T> > {
+public:
+RefCountedData() : data() {}
+RefCountedData(const T& in_value) : data(in_value) {}
+T data;
+private:
+friend class base::RefCountedThreadSafe<base::RefCountedData<T> >;
+~RefCountedData() {}
+};
+}  // namespace base
+//
+// A smart pointer class for reference counted objects.  Use this class instead
+// of calling AddRef and Release manually on a reference counted object to
+// avoid common memory leaks caused by forgetting to Release an object
+// reference.  Sample usage:
+//
+//   class MyFoo : public RefCounted<MyFoo> {
+//    ...
+//   };
+//
+//   void some_function() {
+//     scoped_refptr<MyFoo> foo = new MyFoo();
+//     foo->Method(param);
+//     // |foo| is released when this function returns
+//   }
+//
+//   void some_other_function() {
+//     scoped_refptr<MyFoo> foo = new MyFoo();
+//     ...
+//     foo = NULL;  // explicitly releases |foo|
+//     ...
+//     if (foo)
+//       foo->Method(param);
+//   }
+//
+// The above examples show how scoped_refptr<T> acts like a pointer to T.
+// Given two scoped_refptr<T> classes, it is also possible to exchange
+// references between the two objects, like so:
+//
+//   {
+//     scoped_refptr<MyFoo> a = new MyFoo();
+//     scoped_refptr<MyFoo> b;
+//
+//     b.swap(a);
+//     // now, |b| references the MyFoo object, and |a| references NULL.
+//   }
+//
+// To make both |a| and |b| in the above example reference the same MyFoo
+// object, simply use the assignment operator:
+//
+//   {
+//     scoped_refptr<MyFoo> a = new MyFoo();
+//     scoped_refptr<MyFoo> b;
+//
+//     b = a;
+//     // now, |a| and |b| each own a reference to the same MyFoo object.
+//   }
+//
+template <class T>
+class scoped_refptr {
+public:
+typedef T element_type;
+scoped_refptr() : ptr_(NULL) {
+}
+scoped_refptr(T* p) : ptr_(p) {
+if (ptr_)
+ptr_->AddRef();
+}
+scoped_refptr(const scoped_refptr<T>& r) : ptr_(r.ptr_) {
+if (ptr_)
+ptr_->AddRef();
+}
+template <typename U>
+scoped_refptr(const scoped_refptr<U>& r) : ptr_(r.get()) {
+if (ptr_)
+ptr_->AddRef();
+}
+~scoped_refptr() {
+if (ptr_)
+ptr_->Release();
+}
+T* get() const { return ptr_; }
+operator T*() const { return ptr_; }
+T* operator->() const {
+assert(ptr_ != NULL);
+return ptr_;
+}
+scoped_refptr<T>& operator=(T* p) {
+// AddRef first so that self assignment should work
+if (p)
+p->AddRef();
+T* old_ptr = ptr_;
+ptr_ = p;
+if (old_ptr)
+old_ptr->Release();
+return *this;
+}
+scoped_refptr<T>& operator=(const scoped_refptr<T>& r) {
+return *this = r.ptr_;
+}
+template <typename U>
+scoped_refptr<T>& operator=(const scoped_refptr<U>& r) {
+return *this = r.get();
+}
+void swap(T** pp) {
+T* p = ptr_;
+ptr_ = *pp;
+*pp = p;
+}
+void swap(scoped_refptr<T>& r) {
+swap(&r.ptr_);
+}
+protected:
+T* ptr_;
+};
+// Handy utility for creating a scoped_refptr<T> out of a T* explicitly without
+// having to retype all the template arguments
+template <typename T>
+scoped_refptr<T> make_scoped_refptr(T* t) {
+return scoped_refptr<T>(t);
+}
+#endif  // BASE_MEMORY_REF_COUNTED_H_

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comparison: security/sandbox/chromium/base/memory/ref_counted.h

security/sandbox/chromium/base/memory/ref_counted.h