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 UPDATE_ENGINE_COMMON_FILE_FETCHER_H_ 18 #define UPDATE_ENGINE_COMMON_FILE_FETCHER_H_ 19 20 #include <memory> 21 #include <string> 22 #include <utility> 23 24 #include <base/logging.h> 25 #include <base/macros.h> 26 #include <brillo/streams/stream.h> 27 28 #include "update_engine/common/http_fetcher.h" 29 30 // This is a concrete implementation of HttpFetcher that reads files 31 // asynchronously. 32 33 namespace chromeos_update_engine { 34 35 class FileFetcher : public HttpFetcher { 36 public: 37 // Returns whether the passed url is supported. 38 static bool SupportedUrl(const std::string& url); 39 FileFetcher()40 FileFetcher() : HttpFetcher() {} 41 42 // Cleans up all internal state. Does not notify delegate. 43 ~FileFetcher() override; 44 45 // HttpFetcher overrides. SetOffset(off_t offset)46 void SetOffset(off_t offset) override { offset_ = offset; } SetLength(size_t length)47 void SetLength(size_t length) override { data_length_ = length; } UnsetLength()48 void UnsetLength() override { SetLength(0); } 49 50 // Begins the transfer if it hasn't already begun. 51 void BeginTransfer(const std::string& url) override; 52 53 // If the transfer is in progress, aborts the transfer early. The transfer 54 // cannot be resumed. 55 void TerminateTransfer() override; 56 57 // Ignore all extra headers for files. SetHeader(const std::string & header_name,const std::string & header_value)58 void SetHeader(const std::string& header_name, 59 const std::string& header_value) override {} 60 GetHeader(const std::string & header_name,std::string * header_value)61 bool GetHeader(const std::string& header_name, 62 std::string* header_value) const override { 63 header_value->clear(); 64 return false; 65 } 66 67 // Suspend the asynchronous file read. 68 void Pause() override; 69 70 // Resume the suspended file read. 71 void Unpause() override; 72 GetBytesDownloaded()73 size_t GetBytesDownloaded() override { 74 return static_cast<size_t>(bytes_copied_); 75 } 76 77 // Ignore all the time limits for files. set_low_speed_limit(int low_speed_bps,int low_speed_sec)78 void set_low_speed_limit(int low_speed_bps, int low_speed_sec) override {} set_connect_timeout(int connect_timeout_seconds)79 void set_connect_timeout(int connect_timeout_seconds) override {} set_max_retry_count(int max_retry_count)80 void set_max_retry_count(int max_retry_count) override {} 81 82 private: 83 // Cleans up the fetcher, resetting its status to a newly constructed one. 84 void CleanUp(); 85 86 // Schedule a new asynchronous read if the stream is not paused and no other 87 // read is in process. This method can be called at any point. 88 void ScheduleRead(); 89 90 // Called from the main loop when a single read from |stream_| succeeds or 91 // fails, calling OnReadDoneCallback() and OnReadErrorCallback() respectively. 92 void OnReadDoneCallback(size_t bytes_read); 93 void OnReadErrorCallback(const brillo::Error* error); 94 95 // Whether the transfer was started and didn't finish yet. 96 bool transfer_in_progress_{false}; 97 98 // Whether the transfer is paused. 99 bool transfer_paused_{false}; 100 101 // Whether there's an ongoing asynchronous read. When this value is true, the 102 // the |buffer_| is being used by the |stream_|. 103 bool ongoing_read_{false}; 104 105 // Total number of bytes copied. 106 uint64_t bytes_copied_{0}; 107 108 // The offset inside the file where the read should start. 109 uint64_t offset_{0}; 110 111 // The length of the data or -1 if unknown (will read until EOF). 112 int64_t data_length_{-1}; 113 114 brillo::StreamPtr stream_; 115 116 // The buffer used for reading from the stream. 117 brillo::Blob buffer_; 118 119 DISALLOW_COPY_AND_ASSIGN(FileFetcher); 120 }; 121 122 } // namespace chromeos_update_engine 123 124 #endif // UPDATE_ENGINE_COMMON_FILE_FETCHER_H_ 125