AU: MultiHttpFetcher, an HttpFetcher for specific byte ranges

http_fetcher.h

 // Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_HTTP_FETCHER_H__
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_HTTP_FETCHER_H__
 
 #include <string>
 #include <vector>
 #include <glib.h>
@@ skipping 24 matching lines @@
 
   // Optional: Post data to the server. The HttpFetcher should make a copy
   // of this data and upload it via HTTP POST during the transfer.
   void SetPostData(const void* data, size_t size) {
     post_data_set_ = true;
     post_data_.clear();
     const char *char_data = reinterpret_cast<const char*>(data);
     post_data_.insert(post_data_.end(), char_data, char_data + size);
   }
 
+  // Downloading should resume from this offset
+  virtual void SetOffset(off_t offset) = 0;
+
   // Begins the transfer to the specified URL.
   virtual void BeginTransfer(const std::string& url) = 0;
 
   // Aborts the transfer. TransferComplete() will not be called on the
   // delegate.
   virtual void TerminateTransfer() = 0;
 
   // If data is coming in too quickly, you can call Pause() to pause the
   // transfer. The delegate will not have ReceivedBytes() called while
   // an HttpFetcher is paused.
   virtual void Pause() = 0;
 
   // Used to unpause an HttpFetcher and let the bytes stream in again.
   // If a delegate is set, ReceivedBytes() may be called on it before
   // Unpause() returns
   virtual void Unpause() = 0;
 
+  // These two function are overloaded in LibcurlHttp fetcher to speed
+  // testing.
+  virtual void set_idle_seconds(int seconds) {}
+  virtual void set_retry_seconds(int seconds) {}
+
  protected:
   // The URL we're actively fetching from
   std::string url_;
 
   // POST data for the transfer, and whether or not it was ever set
   bool post_data_set_;
   std::vector<char> post_data_;
 
   // The server's HTTP response code from the last transfer. This
   // field should be set to 0 when a new transfer is initiated, and
@@ skipping 16 matching lines @@
                              int length) = 0;
 
   // Called when the transfer has completed successfully or been somehow
   // aborted.
   virtual void TransferComplete(HttpFetcher* fetcher, bool successful) = 0;
 };
 
 }  // namespace chromeos_update_engine
 
 #endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_HTTP_FETCHER_H__