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      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_
     49