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 <string>
   9
  10 #include "mojo/public/cpp/application/connect.h"
  11 #include "mojo/public/interfaces/application/service_provider.mojom.h"
  12
  13 namespace mojo {
  14
  15 template<typename Interface>
  16 class LazyInterfacePtr : public InterfacePtr<Interface> {
  17  public:
  18   LazyInterfacePtr() : service_provider_(NULL) {}
  19
  20   LazyInterfacePtr(ServiceProvider* service_provider)
  21       : service_provider_(service_provider) {
  22   }
  23
  24   void set_service_provider(ServiceProvider* service_provider) {
  25     if (service_provider != service_provider_) {
  26       InterfacePtr<Interface>::reset();
  27     }
  28     service_provider_ = service_provider;
  29   }
  30
  31   Interface* get() const {
  32     if (!InterfacePtr<Interface>::get()) {
  33       mojo::ConnectToService<Interface>(
  34           service_provider_,
  35           const_cast<LazyInterfacePtr<Interface>*>(this));
  36     }
  37     return InterfacePtr<Interface>::get();
  38   }
  39   Interface* operator->() const { return get(); }
  40   Interface& operator*() const { return *get(); }
  41
  42  private:
  43   ServiceProvider* service_provider_;
  44 };
  45
  46 }  // namespace mojo
  47
  48 #endif  // MOJO_PUBLIC_CPP_APPLICATION_LAZY_INTERFACE_PTR_H_