src/mojo/public/cpp/application/lazy_interface_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_APPLICATION_LAZY_INTERFACE_PTR_H_
   6 #define MOJO_PUBLIC_CPP_APPLICATION_LAZY_INTERFACE_PTR_H_
   7
   8 #include "mojo/public/cpp/application/connect.h"
   9 #include "mojo/public/interfaces/application/service_provider.mojom.h"
  10
  11 namespace mojo {
  12
  13 template <typename Interface>
  14 class LazyInterfacePtr : public InterfacePtr<Interface> {
  15  public:
  16   LazyInterfacePtr() : service_provider_(nullptr) {}
  17
  18   LazyInterfacePtr(ServiceProvider* service_provider)
  19       : service_provider_(service_provider) {}
  20
  21   void set_service_provider(ServiceProvider* service_provider) {
  22     if (service_provider != service_provider_) {
  23       InterfacePtr<Interface>::reset();
  24     }
  25     service_provider_ = service_provider;
  26   }
  27
  28   Interface* get() const {
  29     if (!InterfacePtr<Interface>::get()) {
  30       mojo::ConnectToService<Interface>(
  31           service_provider_, const_cast<LazyInterfacePtr<Interface>*>(this));
  32     }
  33     return InterfacePtr<Interface>::get();
  34   }
  35   Interface* operator->() const { return get(); }
  36   Interface& operator*() const { return *get(); }
  37
  38  private:
  39   ServiceProvider* service_provider_;
  40 };
  41
  42 }  // namespace mojo
  43
  44 #endif  // MOJO_PUBLIC_CPP_APPLICATION_LAZY_INTERFACE_PTR_H_