mojo/public/cpp/bindings/lib/shared_ptr.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_SHARED_PTR_H_
   6 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_SHARED_PTR_H_
   7
   8 #include "mojo/public/cpp/bindings/lib/shared_data.h"
   9
  10 namespace mojo {
  11 namespace internal {
  12
  13 // Used to manage a heap-allocated instance of P that can be shared via
  14 // reference counting. When the last reference is dropped, the instance is
  15 // deleted.
  16 template <typename P>
  17 class SharedPtr {
  18  public:
  19   SharedPtr() {}
  20
  21   explicit SharedPtr(P* ptr) {
  22     impl_.mutable_value()->ptr = ptr;
  23   }
  24
  25   // Default copy-constructor and assignment operator are OK.
  26
  27   P* get() {
  28     return impl_.value().ptr;
  29   }
  30   const P* get() const {
  31     return impl_.value().ptr;
  32   }
  33
  34   P* operator->() { return get(); }
  35   const P* operator->() const { return get(); }
  36
  37  private:
  38   class Impl {
  39    public:
  40     ~Impl() {
  41       if (ptr)
  42         delete ptr;
  43     }
  44
  45     Impl() : ptr(NULL) {
  46     }
  47
  48     Impl(P* ptr) : ptr(ptr) {
  49     }
  50
  51     P* ptr;
  52
  53    private:
  54     MOJO_DISALLOW_COPY_AND_ASSIGN(Impl);
  55   };
  56
  57   SharedData<Impl> impl_;
  58 };
  59
  60 }  // namespace mojo
  61 }  // namespace internal
  62
  63 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_SHARED_PTR_H_