Detect file system errors during downloads.

content/browser/download/base_file.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/base_file.h"
 
 #include "base/file_util.h"
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "base/stringprintf.h"
@@ skipping 185 matching lines @@
   win_util::SetInternetZoneIdentifier(full_path_,
                                       UTF8ToWide(source_url_.spec()));
 #elif defined(OS_MACOSX)
   file_metadata::AddQuarantineMetadataToFile(full_path_, source_url_,
                                              referrer_url_);
   file_metadata::AddOriginMetadataToFile(full_path_, source_url_,
                                          referrer_url_);
 #endif
 }
 
+void BaseFile::CreateFileStream() {
+  file_stream_.reset(new net::FileStream);
+}
+
 bool BaseFile::Open() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   DCHECK(!detached_);
   DCHECK(!full_path_.empty());
 
   // Create a new file stream if it is not provided.
   if (!file_stream_.get()) {
-    file_stream_.reset(new net::FileStream);
+    CreateFileStream();
     if (file_stream_->Open(full_path_,
                            base::PLATFORM_FILE_OPEN_ALWAYS |
                                base::PLATFORM_FILE_WRITE) != net::OK) {
       file_stream_.reset();
       return false;
     }
 
     // We may be re-opening the file after rename. Always make sure we're
     // writing at the end of the file.
     if (file_stream_->Seek(net::FROM_END, 0) < 0) {
@@ skipping 23 matching lines @@
 
 std::string BaseFile::DebugString() const {
   return base::StringPrintf("{ source_url_ = \"%s\""
                             " full_path_ = \"%" PRFilePath "\""
                             " bytes_so_far_ = %" PRId64 " detached_ = %c }",
                             source_url_.spec().c_str(),
                             full_path_.value().c_str(),
                             bytes_so_far_,
                             detached_ ? 'T' : 'F');
 }