1 // 2 // Copyright (C) 2017 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 UPDATE_ENGINE_PAYLOAD_CONSUMER_EXTENT_READER_H_ 18 #define UPDATE_ENGINE_PAYLOAD_CONSUMER_EXTENT_READER_H_ 19 20 #include <vector> 21 22 #include "update_engine/payload_consumer/file_descriptor.h" 23 #include "update_engine/update_metadata.pb.h" 24 25 namespace chromeos_update_engine { 26 27 // ExtentReader is an abstract class with reads from a given file descriptor at 28 // the extents given. 29 class ExtentReader { 30 public: 31 virtual ~ExtentReader() = default; 32 33 // Initializes |ExtentReader| 34 virtual bool Init(FileDescriptorPtr fd, 35 const google::protobuf::RepeatedPtrField<Extent>& extents, 36 uint32_t block_size) = 0; 37 38 // Seeks to the given |offset| assuming all extents are concatenated together. 39 virtual bool Seek(uint64_t offset) = 0; 40 41 // Returns true on success. 42 virtual bool Read(void* buffer, size_t count) = 0; 43 }; 44 45 // DirectExtentReader is probably the simplest ExtentReader implementation. 46 // It reads the data directly from the extents. 47 class DirectExtentReader : public ExtentReader { 48 public: 49 DirectExtentReader() = default; 50 ~DirectExtentReader() override = default; 51 52 bool Init(FileDescriptorPtr fd, 53 const google::protobuf::RepeatedPtrField<Extent>& extents, 54 uint32_t block_size) override; 55 bool Seek(uint64_t offset) override; 56 bool Read(void* bytes, size_t count) override; 57 58 private: 59 FileDescriptorPtr fd_{nullptr}; 60 google::protobuf::RepeatedPtrField<Extent> extents_; 61 size_t block_size_{0}; 62 63 // Current extent being read from |fd_|. 64 google::protobuf::RepeatedPtrField<Extent>::iterator cur_extent_; 65 66 // Bytes read from |cur_extent_| thus far. 67 uint64_t cur_extent_bytes_read_{0}; 68 69 // Offset assuming all extents are concatenated. 70 uint64_t offset_{0}; 71 72 // The accelaring upper bounds for |extents_| if we assume all extents are 73 // concatenated. 74 std::vector<uint64_t> extents_upper_bounds_; 75 uint64_t total_size_{0}; 76 77 DISALLOW_COPY_AND_ASSIGN(DirectExtentReader); 78 }; 79 80 } // namespace chromeos_update_engine 81 82 #endif // UPDATE_ENGINE_PAYLOAD_CONSUMER_EXTENT_READER_H_ 83