public static EntryPartition?FindLastMessagePartitionKey(IAzureDiagnosticLogsTable wadTable, DateTime utcNow, CancellationToken cancellation)
{
if (utcNow.Kind != DateTimeKind.Utc)
{
throw new ArgumentException("time must be of UTC kind", "utcNow");
}
var rangeForBinarySearch = GetRangeForLastMessageBinarySearch(wadTable, utcNow, cancellation);
if (rangeForBinarySearch == null)
{
return(null);
}
EntryPartition begin = rangeForBinarySearch.Item1;
EntryPartition end = rangeForBinarySearch.Item2;
int searchRangeDuration = EntryPartition.Distance(begin, end);
int pos = ListUtils.BinarySearch(
new ListUtils.VirtualList <int>(searchRangeDuration, i => i), 0, searchRangeDuration,
i => {
cancellation.ThrowIfCancellationRequested();
return(wadTable.GetFirstEntryOlderThan(begin.Advance(i).ToString()) != null);
});
if (pos == searchRangeDuration)
{
return(null);
}
return(begin.Advance(pos));
}
static Tuple <EntryPartition, EntryPartition> GetRangeForLowerReversedDateBoundBinarySearch(
IAzureDiagnosticLogsTable wadTable,
long dateTicks,
EntryPartition searchRangeBegin,
CancellationToken cancellationToken)
{
EntryPartition datePartition = new EntryPartition(new EntryTimestamp(dateTicks));
EntryPartition lastStepPartition = datePartition;
for (int step = 1; ; step *= 2)
{
EntryPartition p = EntryPartition.Max(searchRangeBegin, datePartition.Advance(step));
if (EntryPartition.Compare(p, lastStepPartition) == 0)
{
return(null);
}
var tmp = wadTable.GetFirstEntryOlderThan(p.ToString());
if (tmp != null && tmp.EventTickCount < dateTicks)
{
return(new Tuple <EntryPartition, EntryPartition>(
new EntryPartition(tmp.PartitionKey),
lastStepPartition.Advance()));
}
lastStepPartition = p;
cancellationToken.ThrowIfCancellationRequested();
}
}
static Tuple <EntryPartition, EntryPartition> GetRangeForLastMessageBinarySearch(IAzureDiagnosticLogsTable wadTable, DateTime utcNow, CancellationToken cancellation)
{
EntryPartition initialPartition = new EntryTimestamp(utcNow).Partition;
bool thereAreEntriesOlderThanNow = wadTable.GetFirstEntryOlderThan(initialPartition.ToString()) != null;
bool searchingForward = thereAreEntriesOlderThanNow;
EntryPartition currentPartition = initialPartition;
for (long step = searchingForward ? 1 : -1; ; step *= 2)
{
cancellation.ThrowIfCancellationRequested();
EntryPartition t = initialPartition.Advance(step);
if (EntryPartition.Compare(currentPartition, t) == 0)
{
return(null);
}
var tmp = wadTable.GetFirstEntryOlderThan(t.ToString());
if (searchingForward)
{
if (tmp == null)
{
return(new Tuple <EntryPartition, EntryPartition>(currentPartition.Advance(), t));
}
}
else
{
if (tmp != null)
{
return(new Tuple <EntryPartition, EntryPartition>(new EntryPartition(tmp.EventTickCount), currentPartition.Advance()));
}
}
currentPartition = t;
}
}
static IndexedAzureDiagnosticLogEntry FindLowerReversedDateBoundInPartition(IAzureDiagnosticLogsTable wadTable,
EntryPartition partition, long dateTicks, CancellationToken cancellation)
{
var ret = LoadEntriesRange(wadTable, partition, partition.Advance(), null, cancellation)
.LastOrDefault(e => e.Entry.EventTickCount <= dateTicks);
return(ret);
}
static IndexedAzureDiagnosticLogEntry?FindLowerReversedDateBound(
IAzureDiagnosticLogsTable wadTable,
DateTime date,
EntryPartition searchRangeBegin,
CancellationToken cancellationToken)
{
EntryTimestamp dateTimestamp = new EntryTimestamp(date);
var ret = FindLowerReversedDateBoundInPartition(wadTable, dateTimestamp.Partition, dateTimestamp.Ticks, cancellationToken);
if (ret.Entry != null)
{
return(ret);
}
var rangeForBinarySearch = GetRangeForLowerReversedDateBoundBinarySearch(wadTable, dateTimestamp.Ticks,
searchRangeBegin, cancellationToken);
if (rangeForBinarySearch == null)
{
return(null);
}
EntryPartition begin = rangeForBinarySearch.Item1;
EntryPartition end = rangeForBinarySearch.Item2;
int searchRangeDuration = (int)EntryPartition.Distance(begin, end);
int pos = ListUtils.BinarySearch(
new ListUtils.VirtualList <int>(searchRangeDuration, i => i), 0, searchRangeDuration,
timeBeingTested =>
{
cancellationToken.ThrowIfCancellationRequested();
var firstEntryFollowingTimeBeingTested = wadTable.GetFirstEntryOlderThan(begin.Advance(timeBeingTested).ToString());
bool lessThanBoundaryBeingSearched;
if (firstEntryFollowingTimeBeingTested == null)
{
lessThanBoundaryBeingSearched = false;
}
else
{
lessThanBoundaryBeingSearched = firstEntryFollowingTimeBeingTested.EventTickCount < dateTimestamp.Ticks;
}
return(lessThanBoundaryBeingSearched);
});
if (pos == searchRangeDuration)
{
return(null);
}
ret = FindLowerReversedDateBoundInPartition(wadTable, begin.Advance(pos), dateTimestamp.Ticks, cancellationToken);
if (ret.Entry != null)
{
return(ret);
}
return(null);
}
