diff options
| author | jsbell <jsbell@chromium.org> | 2015-09-01 17:55:03 -0700 |
|---|---|---|
| committer | Commit bot <commit-bot@chromium.org> | 2015-09-02 00:55:39 +0000 |
| commit | 1d45da203ac9fc8ea3f119edf9030d8e948722a3 (patch) | |
| tree | 704760bf7c661adcc3155576b9bf16e3d4f20c82 /storage/browser | |
| parent | a777250f5630d1e4880d9a4430aa7bdc7e18e23f (diff) | |
| download | chromium_src-1d45da203ac9fc8ea3f119edf9030d8e948722a3.zip chromium_src-1d45da203ac9fc8ea3f119edf9030d8e948722a3.tar.gz chromium_src-1d45da203ac9fc8ea3f119edf9030d8e948722a3.tar.bz2 | |
FileAPI: Compare expected modification time with delta on file read
The File API reader validates that the "expected" modification time -
e.g. taken when a user selects a file via <input type=file> matches
the "actual" modification time when trying to read. Certain file
timestamps (on Windows/NTFS at least) are high enough precision
(tenths of microseconds) that an int64->double->int64 round trip
through Blink loses bits. Files with these timestamps can't be read!
Sample timestamp: 2011-01-01T01:23:45.999999Z (that's a lot of 9s)
Make the comparison with an epsilon of 10us.
BUG=525088
R=michaeln@chromium.org
Review URL: https://codereview.chromium.org/1308773006
Cr-Commit-Position: refs/heads/master@{#346802}
Diffstat (limited to 'storage/browser')
| -rw-r--r-- | storage/browser/fileapi/file_stream_reader.cc | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/storage/browser/fileapi/file_stream_reader.cc b/storage/browser/fileapi/file_stream_reader.cc index cb87ecb..00d3e22 100644 --- a/storage/browser/fileapi/file_stream_reader.cc +++ b/storage/browser/fileapi/file_stream_reader.cc @@ -8,13 +8,18 @@ namespace storage { +// Int64->double->int64 conversions (e.g. through Blink) may lose some +// precision in the microsecond range. Allow 10us delta. +const int kModificationTimeAllowedDeltaMicroseconds = 10; + // Verify if the underlying file has not been modified. bool FileStreamReader::VerifySnapshotTime( const base::Time& expected_modification_time, const base::File::Info& file_info) { return expected_modification_time.is_null() || - expected_modification_time.ToTimeT() == - file_info.last_modified.ToTimeT(); + (expected_modification_time - file_info.last_modified) + .magnitude() + .InMicroseconds() < kModificationTimeAllowedDeltaMicroseconds; } } // namespace storage |