private bool IsFileContentsUpToDate(FullPathChanges fullPathChanges, FileData oldFileData)
{
Debug.Assert(oldFileData.Contents != null);
var fullPath = oldFileData.FileName.FullPath;
if (fullPathChanges != null)
{
// We don't get file change events for file in symlinks, so we can't
// rely on fullPathChanges contents for our heuristic of avoiding file
// system access.
if (!FileDatabase.IsContainedInSymLinkHelper(_directories, oldFileData.FileName))
{
return(fullPathChanges.GetPathChangeKind(fullPath) == PathChangeKind.None);
}
}
// Do the "expensive" check by going to the file system.
var fi = _fileSystem.GetFileInfoSnapshot(fullPath);
return
((fi.Exists) &&
(fi.IsFile) &&
(fi.LastWriteTimeUtc == oldFileData.Contents.UtcLastModified));
}
private IEnumerable <FileData> GetCommonFiles(FileDatabase oldState)
{
if (_files.Count == 0 || oldState.Files.Count == 0)
{
return(Enumerable.Empty <FileData>());
}
return(oldState.Files.Values.Intersect(_files.Values.Select(x => x.FileData), FileDataComparer.Instance));
}
/// <summary>
/// Prepares this instance for searches by computing various snapshots from
/// the previous <see cref="FileDatabase"/> snapshot and the new current
/// <see cref="FileSystemTreeSnapshot"/> instance.
/// </summary>
private FileDatabase ComputeFileDatabase(FileDatabase previousFileDatabase, FileSystemTreeSnapshot newSnapshot)
{
if (previousFileDatabase == null)
{
throw new ArgumentNullException("previousFileDatabase");
}
if (newSnapshot == null)
{
throw new ArgumentNullException("newSnapshot");
}
// Compute list of files from tree
ComputeFileCollection(newSnapshot);
// Merge old state in new state
TransferUnchangedFileContents(previousFileDatabase);
// Load file contents into newState
ReadMissingFileContents();
return(CreateFileDatabse());
}
private void TransferUnchangedFileContents(FileDatabase oldState)
{
Logger.Log("Checking for out of date files.");
var sw = Stopwatch.StartNew();
IList <FileData> commonOldFiles = GetCommonFiles(oldState).ToArray();
using (var progress = _progressTrackerFactory.CreateTracker(commonOldFiles.Count)) {
commonOldFiles
.AsParallel()
.Where(oldFileData => {
if (progress.Step())
{
progress.DisplayProgress((i, n) => string.Format("Checking file timestamp {0:n0} of {1:n0}: {2}", i, n, oldFileData.FileName.FullPathName));
}
return(IsFileContentsUpToDate(oldFileData));
})
.ForAll(oldFileData => _files[oldFileData.FileName].FileData.UpdateContents(oldFileData.Contents));
}
Logger.Log("Done checking for {0:n0} out of date files in {1:n0} msec.", commonOldFiles.Count,
sw.ElapsedMilliseconds);
Logger.LogMemoryStats();
}