Added member data to classes to support download resumption.

content/browser/download/download_resource_handler.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/download/download_resource_handler.h"
 
 #include <string>
 
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
@@ skipping 33 matching lines @@
       global_id_(render_process_host_id, request_id),
       render_view_id_(render_view_id),
       content_length_(0),
       download_file_manager_(download_file_manager),
       request_(request),
       save_as_(save_as),
       started_cb_(started_cb),
       save_info_(save_info),
       buffer_(new content::DownloadBuffer),
       rdh_(rdh),
-      is_paused_(false) {
+      is_paused_(false),
+      was_interrupted_(false),
+      interrupted_bytes_(0) {
   DCHECK(dl_id.IsValid());
   download_stats::RecordDownloadCount(download_stats::UNTHROTTLED_COUNT);
 }
 
 bool DownloadResourceHandler::OnUploadProgress(int request_id,
                                                uint64 position,
                                                uint64 size) {
   return true;
 }
 
@@ skipping 22 matching lines @@
     ResourceDispatcherHost::InfoForRequest(request_);
 
   // Deleted in DownloadManager.
   DownloadCreateInfo* info = new DownloadCreateInfo(FilePath(), GURL(),
       base::Time::Now(), 0, content_length_, DownloadItem::IN_PROGRESS,
       download_id_.local(), request_info->has_user_gesture(),
       request_info->transition_type());
   info->url_chain = request_->url_chain();
   info->referrer_url = GURL(request_->referrer());
   info->start_time = base::Time::Now();
-  info->received_bytes = 0;
+  info->received_bytes = was_interrupted_ ? interrupted_bytes_ : 0;
   info->total_bytes = content_length_;
   info->state = DownloadItem::IN_PROGRESS;
   info->download_id = download_id_.local();
   info->has_user_gesture = request_info->has_user_gesture();
   info->content_disposition = content_disposition_;
   info->mime_type = response->response_head.mime_type;
   download_stats::RecordDownloadMimeType(info->mime_type);
+  info->continued_download = was_interrupted_;
 
   DownloadRequestHandle request_handle(rdh_, global_id_.child_id,
                                        render_view_id_, global_id_.request_id);
 
-  // TODO(ahendrickson) -- Get the last modified time and etag, so we can
-  // resume downloading.
+  // If we're starting a new download, get the last modified time and etag.

[Randy Smith (Not in Mondays), 2011/10/31 18:46:43]

Why don't we get these all the time?  Why conditionalize?  My sense is that we
need them on both start and restart to compare against each other, but even if
we don't, the code's simpler if we always get them.

[ahendrickson, 2011/11/13 21:15:20]

Done.

+  if (was_interrupted_) {
+    const net::HttpResponseHeaders* headers = request_->response_headers();
+    if (headers) {
+      std::string last_modified_hdr;
+      std::string etag;
+      if (headers->EnumerateHeader(NULL, "Last-Modified", &last_modified_hdr))
+        info->last_modified = last_modified_hdr;
+      if (headers->EnumerateHeader(NULL, "ETag", &etag))
+        info->etag = etag;
+    }
+  }
 
   CallStartedCB(net::OK);
 
   std::string content_type_header;
   if (!response->response_head.headers ||
       !response->response_head.headers->GetMimeType(&content_type_header))
     content_type_header = "";
   info->original_mime_type = content_type_header;
 
   info->prompt_user_for_save_location =
@@ skipping 172 matching lines @@
                             " render_view_id_ = " "%d"
                             " save_info_.file_path = \"%" PRFilePath "\""
                             " }",
                             request_->url().spec().c_str(),
                             download_id_.local(),
                             global_id_.child_id,
                             global_id_.request_id,
                             render_view_id_,
                             save_info_.file_path.value().c_str());
 }