Download resumption - Preliminary

content/browser/download/download_resource_handler.cc

Index: content/browser/download/download_resource_handler.cc
diff --git a/content/browser/download/download_resource_handler.cc b/content/browser/download/download_resource_handler.cc
index 29f7e8e194fcca59bb94c18c8a81f493ca7e0588..fa4fb84a761a66a923bc7e080795e729500b7d74 100644
--- a/content/browser/download/download_resource_handler.cc
+++ b/content/browser/download/download_resource_handler.cc
@@ -172,6 +172,14 @@ bool DownloadResourceHandler::OnResponseStarted(
       info->last_modified = last_modified_hdr;
     if (headers->EnumerateHeader(NULL, "ETag", &etag))
       info->etag = etag;
+
+    int status = headers->response_code();
+    if (status == 200) {  // Continue with download:
+      // Downloading the full file, even if we asked for a range.
+      // If there is a temporary file and |received_bytes == 0|, delete it.
+      save_info_->offset = 0;
+      save_info_->hash_state = "";
+    }
   }
 
   std::string content_type_header;
@@ -322,19 +330,32 @@ bool DownloadResourceHandler::OnResponseCompleted(
     reason = DOWNLOAD_INTERRUPT_REASON_USER_CANCELED;
   }
 
-  if (status.is_success()) {
-    if (response_code >= 400) {
+  if (status.is_success() &&
+      (reason == DOWNLOAD_INTERRUPT_REASON_NONE) &&
+      request_->response_headers()) {
+    // Handle server's response codes.
+    if ((response_code >= 0) && ((response_code % 100) != 2)) {
       switch(response_code) {
-        case 404:  // File Not Found.
+        // Continue with download:
+        case 200:   // Downloading the full file, even if we asked for a
+                    // range.
+        case 206:   // Partial content.  Leave alone.
+          break;
+        case 204:   // No content.  File not present.
+        case 404:   // File Not Found.
           reason = DOWNLOAD_INTERRUPT_REASON_SERVER_BAD_CONTENT;
           break;
+        case 412:   // Precondition failed.  Fails 'If-Unmodified-Since' or
+                    // 'If-Match'.
+          reason = DOWNLOAD_INTERRUPT_REASON_SERVER_PRECONDITION;
+          break;
         case 416:  // Range Not Satisfiable.
+          // Retry by downloading from the start automatically:
+          // If we haven't received data when we get this error, we won't.
           reason = DOWNLOAD_INTERRUPT_REASON_SERVER_NO_RANGE;
-          break;
-        case 412:  // Precondition Failed.
           reason = DOWNLOAD_INTERRUPT_REASON_SERVER_PRECONDITION;
           break;
-        default:
+        default:    // All other errors.
           reason = DOWNLOAD_INTERRUPT_REASON_SERVER_FAILED;
           break;
       }