storage/browser/fileapi/file_stream_reader.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "storage/browser/fileapi/file_stream_reader.h"
   6
   7 #include "base/time/time.h"
   8
   9 namespace storage {
  10
  11 // Int64->double->int64 conversions (e.g. through Blink) may lose some
  12 // precision in the microsecond range. Allow 10us delta.
  13 const int kModificationTimeAllowedDeltaMicroseconds = 10;
  14
  15 // Verify if the underlying file has not been modified.
  16 bool FileStreamReader::VerifySnapshotTime(
  17     const base::Time& expected_modification_time,
  18     const base::File::Info& file_info) {
  19   return expected_modification_time.is_null() ||
  20          (expected_modification_time - file_info.last_modified)
  21                  .magnitude()
  22                  .InMicroseconds() < kModificationTimeAllowedDeltaMicroseconds;
  23 }
  24
  25 }  // namespace storage