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/message_loops/message_loop.h> 27 #include <brillo/streams/stream.h> 28 29 #include "update_engine/common/http_fetcher.h" 30 31 // This is a concrete implementation of HttpFetcher that reads files 32 // asynchronously. 33 34 namespace chromeos_update_engine { 35 36 class FileFetcher : public HttpFetcher { 37 public: 38 // Returns whether the passed url is supported. 39 static bool SupportedUrl(const std::string& url); 40 FileFetcher()41 FileFetcher() : HttpFetcher(nullptr) {} 42 43 // Cleans up all internal state. Does not notify delegate. 44 ~FileFetcher() override; 45 46 // HttpFetcher overrides. SetOffset(off_t offset)47 void SetOffset(off_t offset) override { offset_ = offset; } SetLength(size_t length)48 void SetLength(size_t length) override { data_length_ = length; } UnsetLength()49 void UnsetLength() override { SetLength(0); } 50 51 // Begins the transfer if it hasn't already begun. 52 void BeginTransfer(const std::string& url) override; 53 54 // If the transfer is in progress, aborts the transfer early. The transfer 55 // cannot be resumed. 56 void TerminateTransfer() override; 57 58 // Ignore all extra headers for files. SetHeader(const std::string & header_name,const std::string & header_value)59 void SetHeader(const std::string& header_name, 60 const std::string& header_value) override {} 61 GetHeader(const std::string & header_name,std::string * header_value)62 bool GetHeader(const std::string& header_name, 63 std::string* header_value) const override { 64 header_value->clear(); 65 return false; 66 } 67 68 // Suspend the asynchronous file read. 69 void Pause() override; 70 71 // Resume the suspended file read. 72 void Unpause() override; 73 GetBytesDownloaded()74 size_t GetBytesDownloaded() override { 75 return static_cast<size_t>(bytes_copied_); 76 } 77 78 // Ignore all the time limits for files. set_low_speed_limit(int low_speed_bps,int low_speed_sec)79 void set_low_speed_limit(int low_speed_bps, int low_speed_sec) override {} set_connect_timeout(int connect_timeout_seconds)80 void set_connect_timeout(int connect_timeout_seconds) override {} set_max_retry_count(int max_retry_count)81 void set_max_retry_count(int max_retry_count) override {} 82 83 private: 84 // Cleans up the fetcher, resetting its status to a newly constructed one. 85 void CleanUp(); 86 87 // Schedule a new asynchronous read if the stream is not paused and no other 88 // read is in process. This method can be called at any point. 89 void ScheduleRead(); 90 91 // Called from the main loop when a single read from |stream_| succeeds or 92 // fails, calling OnReadDoneCallback() and OnReadErrorCallback() respectively. 93 void OnReadDoneCallback(size_t bytes_read); 94 void OnReadErrorCallback(const brillo::Error* error); 95 96 // Whether the transfer was started and didn't finish yet. 97 bool transfer_in_progress_{false}; 98 99 // Whether the transfer is paused. 100 bool transfer_paused_{false}; 101 102 // Whether there's an ongoing asynchronous read. When this value is true, the 103 // the |buffer_| is being used by the |stream_|. 104 bool ongoing_read_{false}; 105 106 // Total number of bytes copied. 107 uint64_t bytes_copied_{0}; 108 109 // The offset inside the file where the read should start. 110 uint64_t offset_{0}; 111 112 // The length of the data or -1 if unknown (will read until EOF). 113 int64_t data_length_{-1}; 114 115 brillo::StreamPtr stream_; 116 117 // The buffer used for reading from the stream. 118 brillo::Blob buffer_; 119 120 DISALLOW_COPY_AND_ASSIGN(FileFetcher); 121 }; 122 123 } // namespace chromeos_update_engine 124 125 #endif // UPDATE_ENGINE_COMMON_FILE_FETCHER_H_ 126