/// <summary>
/// Gets link impact.
/// </summary>
internal static LinkImpact LinkImpact(this UsnChangeReasons reasons)
{
const UsnChangeReasons AllLinkChangeReasons =
UsnChangeReasons.FileDelete |
// Only caused by deletion of the last link, so let's be thrifty and claim 'all links' affected.
UsnChangeReasons.DataExtend |
UsnChangeReasons.DataOverwrite |
UsnChangeReasons.DataTruncation |
UsnChangeReasons.StreamChange |
UsnChangeReasons.ReparsePointChange;
const UsnChangeReasons SingleLinkChangeReasons =
UsnChangeReasons.HardLinkChange | // This is a deletion or creation of a link (other than the last).
UsnChangeReasons.RenameOldName;
if ((reasons & AllLinkChangeReasons) != 0)
{
return(ChangeTracking.LinkImpact.AllLinks);
}
if ((reasons & SingleLinkChangeReasons) != 0)
{
return(ChangeTracking.LinkImpact.SingleLink);
}
return(ChangeTracking.LinkImpact.None);
}
/// <summary>
/// Creates a UsnRecord
/// </summary>
public UsnRecord(FileId file, FileId container, Usn usn, UsnChangeReasons reasons)
{
FileId = file;
ContainerFileId = container;
Usn = usn;
Reason = reasons;
}
private void ExpectChangesSinceUsn(
UsnChangeReasons expectedChangeReasons,
SafeFileHandle volumeHandle,
Usn startUsn,
FileId fileId,
out Usn nextUsn,
TimeSpan?timeLimit = default(TimeSpan?))
{
const int DefaultTimeLimitForScanningInSecond = 30; // 30 sec for scanning.
QueryUsnJournalData journalState = QueryJournal(volumeHandle);
byte[] buffer = new byte[64 * 1024]; // 655 records per read.
timeLimit = timeLimit.HasValue ? timeLimit : TimeSpan.FromSeconds(DefaultTimeLimitForScanningInSecond);
var stopWatch = System.Diagnostics.Stopwatch.StartNew();
UsnChangeReasons foundChangeReasons = 0;
nextUsn = startUsn;
while (true)
{
if (stopWatch.ElapsedTicks > timeLimit.Value.Ticks)
{
break;
}
ReadUsnJournalResult result = FileUtilities.TryReadUsnJournal(
volumeHandle,
buffer,
journalState.UsnJournalId,
startUsn);
nextUsn = result.NextUsn;
if (!result.Succeeded)
{
break;
}
if (result.Records.Count == 0)
{
break;
}
foundChangeReasons |= UsnJournalUtilities.GetAggregateChangeReasons(fileId, result.Records);
if (expectedChangeReasons == (foundChangeReasons & expectedChangeReasons))
{
// Found all expected change reasons.
return;
}
startUsn = result.NextUsn;
}
XAssert.AreEqual(expectedChangeReasons, foundChangeReasons & expectedChangeReasons);
}
/// <summary>
/// Gets membership impacts.
/// </summary>
internal static MembershipImpact MembershipImpact(this UsnChangeReasons reasons)
{
const UsnChangeReasons CreationReasons =
UsnChangeReasons.FileCreate |
UsnChangeReasons.RenameNewName |
UsnChangeReasons.HardLinkChange; // Can be either a creation or deletion
const UsnChangeReasons DeletionReasons =
UsnChangeReasons.FileDelete |
UsnChangeReasons.RenameOldName |
UsnChangeReasons.HardLinkChange; // Can be either a creation or deletion
return(((reasons & CreationReasons) != 0 ? ChangeTracking.MembershipImpact.Creation : ChangeTracking.MembershipImpact.None) |
((reasons & DeletionReasons) != 0 ? ChangeTracking.MembershipImpact.Deletion : ChangeTracking.MembershipImpact.None));
}
public static UsnChangeReasons GetAggregateChangeReasons(
FileId fileFilter,
IEnumerable <UsnRecord> records)
{
UsnChangeReasons reasons = default(UsnChangeReasons);
foreach (UsnRecord record in records)
{
if (fileFilter == record.FileId)
{
reasons |= record.Reason;
}
}
return(reasons);
}
public void ReadChangesToFile()
{
string path = GetFullPath("File");
WithVolumeHandle(
volumeHandle =>
{
Usn initialUsn = QueryJournal(volumeHandle).NextUsn;
FileId fileId;
using (FileStream file = File.Create(path))
{
fileId = FileUtilities.ReadFileUsnByHandle(file.SafeFileHandle).Value.FileId;
file.WriteByte(1);
}
const UsnChangeReasons ExpectedCreationChangeReasons =
UsnChangeReasons.FileCreate |
UsnChangeReasons.DataExtend |
UsnChangeReasons.Close;
Usn nextUsn;
ExpectChangesSinceUsn(ExpectedCreationChangeReasons, volumeHandle, initialUsn, fileId, out nextUsn);
using (FileStream file = File.OpenWrite(path))
{
file.WriteByte(1);
}
File.SetAttributes(path, FileAttributes.Normal | FileAttributes.ReadOnly);
const UsnChangeReasons ExpectedModificationChangeReasons =
UsnChangeReasons.DataOverwrite |
UsnChangeReasons.BasicInfoChange |
UsnChangeReasons.Close;
ExpectChangesSinceUsn(ExpectedModificationChangeReasons, volumeHandle, nextUsn, fileId, out nextUsn);
});
}
