1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef NVRAM_HAL_NVRAM_DEVICE_ADAPTER_H_ 18 #define NVRAM_HAL_NVRAM_DEVICE_ADAPTER_H_ 19 20 #include <memory> 21 22 #include <hardware/nvram.h> 23 #include <nvram/messages/nvram_messages.h> 24 25 namespace nvram { 26 27 // |NvramImplementation| subclasses provide an implementation of the NVRAM HAL 28 // logic. 29 class NvramImplementation { 30 public: 31 virtual ~NvramImplementation() = default; 32 33 // This function services all operations defined for the NVRAM HAL. The input 34 // parameters are passed in |request| and |response| will be filled in with 35 // the result and output parameters of the operation. 36 virtual void Execute(const nvram::Request& request, 37 nvram::Response* response) = 0; 38 }; 39 40 // |NvramDeviceAdapater| provides glue to turn an |NvramImplementation| object 41 // into an |nvram_device_t| as defined by the NVRAM HAL C API. This is intended 42 // to be used in the HAL module's |open()| operation. To obtain the desired 43 // |hw_device_t|, just create an |NvramDeviceAdapter| with a suitable 44 // |NvramImplementation| and call |as_device()| to get the HAL device pointer. 45 struct NvramDeviceAdapter { 46 public: 47 // Takes ownership of |implementation|. 48 NvramDeviceAdapter(const hw_module_t* module, 49 NvramImplementation* implementation); 50 as_deviceNvramDeviceAdapter51 hw_device_t* as_device() { return &device_.common; } nvram_implementationNvramDeviceAdapter52 NvramImplementation* nvram_implementation() { return implementation_.get(); } 53 54 private: 55 nvram_device_t device_; 56 std::unique_ptr<NvramImplementation> implementation_; 57 }; 58 59 // Make sure |NvramDeviceAdapter| is a standard layout type. This guarantees 60 // that casting from/to the type of the first non-static member (i.e. |device_|) 61 // works as expected. 62 static_assert(std::is_standard_layout<NvramDeviceAdapter>::value, 63 "NvramDeviceAdapater must be a standard layout type."); 64 65 } // namespace nvram 66 67 #endif // NVRAM_HAL_NVRAM_DEVICE_ADAPTER_H_ 68