/// <summary>
/// A variant of WrapEnumerable that accepts a QueryOperatorEnumerator{,} instead of an IEnumerable{}.
/// The code duplication is necessary to avoid extra virtual method calls that would otherwise be needed to
/// convert the QueryOperatorEnumerator{,} to an IEnumerator{}.
/// </summary>
internal static IEnumerable <TElement> WrapQueryEnumerator <TElement, TIgnoreKey>(QueryOperatorEnumerator <TElement, TIgnoreKey> source,
CancellationState cancellationState)
{
TElement elem = default(TElement);
TIgnoreKey ignoreKey = default(TIgnoreKey);
try
{
while (true)
{
try
{
if (!source.MoveNext(ref elem, ref ignoreKey))
{
yield break;
}
}
catch (ThreadAbortException)
{
// Do not wrap ThreadAbortExceptions
throw;
}
catch (Exception ex)
{
ThrowOCEorAggregateException(ex, cancellationState);
}
yield return(elem);
}
}
finally
{
source.Dispose();
}
}
//---------------------------------------------------------------------------------------
// Straightforward IEnumerator<T> methods.
//
internal override bool MoveNext(ref TResult currentElement, ref TKey currentKey)
{
// If the buffer has not been created, we will generate it lazily on demand.
if (_buffer == null)
{
// Create a buffer, but don't publish it yet (in case of exception).
List <Pair <TResult, TKey> > buffer = new List <Pair <TResult, TKey> >();
// Enter the search phase. In this phase, we scan the input until one of three
// things happens: (1) all input has been exhausted, (2) the predicate yields
// false for one of our elements, or (3) we move past the current lowest index
// found by other partitions for a false element. As we go, we have to remember
// the elements by placing them into the buffer.
try
{
TResult current = default(TResult);
TKey key = default(TKey);
int i = 0; //counter to help with cancellation
while (_source.MoveNext(ref current, ref key))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
// Add the current element to our buffer.
buffer.Add(new Pair <TResult, TKey>(current, key));
// See if another partition has found a false value before this element. If so,
// we should stop scanning the input now and reach the barrier ASAP.
if (_updatesSeen != _operatorState._updatesDone)
{
lock (_operatorState)
{
_currentLowKey = _operatorState._currentLowKey;
_updatesSeen = _operatorState._updatesDone;
}
}
if (_updatesSeen > 0 && _keyComparer.Compare(key, _currentLowKey) > 0)
{
break;
}
// Evaluate the predicate, either indexed or not based on info passed to the ctor.
bool predicateResult;
if (_predicate != null)
{
predicateResult = _predicate(current);
}
else
{
Debug.Assert(_indexedPredicate != null);
predicateResult = _indexedPredicate(current, key);
}
if (!predicateResult)
{
// Signal that we've found a false element, racing with other partitions to
// set the shared index value.
lock (_operatorState)
{
if (_operatorState._updatesDone == 0 || _keyComparer.Compare(_operatorState._currentLowKey, key) > 0)
{
_currentLowKey = _operatorState._currentLowKey = key;
_updatesSeen = ++_operatorState._updatesDone;
}
}
break;
}
}
}
finally
{
// No matter whether we exit due to an exception or normal completion, we must ensure
// that we signal other partitions that we have completed. Otherwise, we can cause deadlocks.
_sharedBarrier.Signal();
}
// Before exiting the search phase, we will synchronize with others. This is a barrier.
_sharedBarrier.Wait(_cancellationToken);
// Publish the buffer and set the index to just before the 1st element.
_buffer = buffer;
_bufferIndex = new Shared <int>(-1);
}
// Now either enter (or continue) the yielding phase. As soon as we reach this, we know the
// current shared "low false" value is the absolute lowest with a false.
if (_take)
{
// In the case of a take-while, we will yield each element from our buffer for which
// the element is lesser than the lowest false index found.
if (_bufferIndex.Value >= _buffer.Count - 1)
{
return(false);
}
// Increment the index, and remember the values.
++_bufferIndex.Value;
currentElement = _buffer[_bufferIndex.Value].First;
currentKey = _buffer[_bufferIndex.Value].Second;
return(_operatorState._updatesDone == 0 || _keyComparer.Compare(_operatorState._currentLowKey, currentKey) > 0);
}
else
{
// If no false was found, the output is empty.
if (_operatorState._updatesDone == 0)
{
return(false);
}
// In the case of a skip-while, we must skip over elements whose index is lesser than the
// lowest index found. Once we've exhausted the buffer, we must go back and continue
// enumerating the data source until it is empty.
if (_bufferIndex.Value < _buffer.Count - 1)
{
for (_bufferIndex.Value++; _bufferIndex.Value < _buffer.Count; _bufferIndex.Value++)
{
// If the current buffered element's index is greater than or equal to the smallest
// false index found, we will yield it as a result.
if (_keyComparer.Compare(_buffer[_bufferIndex.Value].Second, _operatorState._currentLowKey) >= 0)
{
currentElement = _buffer[_bufferIndex.Value].First;
currentKey = _buffer[_bufferIndex.Value].Second;
return(true);
}
}
}
// Lastly, so long as our input still has elements, they will be yieldable.
if (_source.MoveNext(ref currentElement, ref currentKey))
{
Debug.Assert(_keyComparer.Compare(currentKey, _operatorState._currentLowKey) > 0,
"expected remaining element indices to be greater than smallest");
return(true);
}
}
return(false);
}
//-----------------------------------------------------------------------------------
// Marks the end of a query's execution, waiting for all tasks to finish and
// propagating any relevant exceptions. Note that the full set of tasks must have
// been initialized (with SetTask) before calling this.
//
internal void QueryEnd(bool userInitiatedDispose)
{
Debug.Assert(_rootTask != null);
//Debug.Assert(Task.Current == null || (Task.Current != _rootTask && Task.Current.Parent != _rootTask));
if (Interlocked.Exchange(ref _alreadyEnded, 1) == 0)
{
// There are four cases:
// Case #1: Wait produced an exception that is not OCE(ct), or an AggregateException which is not full of OCE(ct) ==> We rethrow.
// Case #2: External cancellation has been requested ==> we'll manually throw OCE(externalToken).
// Case #3a: We are servicing a call to Dispose() (and possibly also external cancellation has been requested).. simply return.
// Case #3b: The enumerator has already been disposed (and possibly also external cancellation was requested). Throw an ODE.
// Case #4: No exceptions or explicit call to Dispose() by this caller ==> we just return.
// See also "InlinedAggregationOperator" which duplicates some of this logic for the aggregators.
// See also "QueryOpeningEnumerator" which duplicates some of this logic.
// See also "ExceptionAggregator" which duplicates some of this logic.
try
{
// Wait for all the tasks to complete
// If any of the tasks ended in the Faulted stated, an AggregateException will be thrown.
_rootTask.Wait();
}
catch (AggregateException ae)
{
AggregateException flattenedAE = ae.Flatten();
bool allOCEsOnTrackedExternalCancellationToken = true;
for (int i = 0; i < flattenedAE.InnerExceptions.Count; i++)
{
OperationCanceledException?oce = flattenedAE.InnerExceptions[i] as OperationCanceledException;
// we only let it pass through iff:
// it is not null, not default, and matches the exact token we were given as being the external token
// and the external Token is actually canceled (i.e. not a spoof OCE(extCT) for a non-canceled extCT)
if (oce == null ||
!oce.CancellationToken.IsCancellationRequested ||
oce.CancellationToken != _cancellationState.ExternalCancellationToken)
{
allOCEsOnTrackedExternalCancellationToken = false;
break;
}
}
// if all the exceptions were OCE(externalToken), then we will propagate only a single OCE(externalToken) below
// otherwise, we flatten the aggregate (because the WaitAll above already aggregated) and rethrow.
if (!allOCEsOnTrackedExternalCancellationToken || flattenedAE.InnerExceptions.Count == 0)
{
throw flattenedAE; // Case #1
}
}
finally
{
//_rootTask don't support Dispose on some platforms
(_rootTask as IDisposable)?.Dispose();
}
if (_cancellationState.MergedCancellationToken.IsCancellationRequested)
{
// cancellation has occurred but no user-delegate exceptions were detected
// NOTE: it is important that we see other state variables correctly here, and that
// read-reordering hasn't played havoc.
// This is OK because
// 1. all the state writes (e,g. in the Initiate* methods) are volatile writes (standard .NET MM)
// 2. tokenCancellationRequested is backed by a volatile field, hence the reads below
// won't get reordered about the read of token.IsCancellationRequested.
// If the query has already been disposed, we don't want to throw an OCE
if (!_cancellationState.TopLevelDisposedFlag.Value)
{
CancellationState.ThrowWithStandardMessageIfCanceled(_cancellationState.ExternalCancellationToken); // Case #2
}
//otherwise, given that there were no user-delegate exceptions (they would have been rethrown above),
//the only remaining situation is user-initiated dispose.
Debug.Assert(_cancellationState.TopLevelDisposedFlag.Value);
// If we aren't actively disposing, that means somebody else previously disposed
// of the enumerator. We must throw an ObjectDisposedException.
if (!userInitiatedDispose)
{
throw new ObjectDisposedException("enumerator", SR.PLINQ_DisposeRequested); // Case #3
}
}
// Case #4. nothing to do.
}
}
//---------------------------------------------------------------------------------------
// MoveNext implements all the hash-join logic noted earlier. When it is called first, it
// will execute the entire inner query tree, and build a hash-table lookup. This is the
// Building phase. Then for the first call and all subsequent calls to MoveNext, we will
// incrementally perform the Probing phase. We'll keep getting elements from the outer
// data source, looking into the hash-table we built, and enumerating the full results.
//
// This routine supports both inner and outer (group) joins. An outer join will yield a
// (possibly empty) list of matching elements from the inner instead of one-at-a-time,
// as we do for inner joins.
//
internal override bool MoveNext(ref TOutput currentElement, ref TOutputKey currentKey)
{
Debug.Assert(_resultSelector != null, "expected a compiled result selector");
Debug.Assert(_leftSource != null);
Debug.Assert(_rightLookupBuilder != null);
// BUILD phase: If we haven't built the hash-table yet, create that first.
Mutables mutables = _mutables;
if (mutables == null)
{
mutables = _mutables = new Mutables();
mutables._rightHashLookup = _rightLookupBuilder.BuildHashLookup(_cancellationToken);
}
// PROBE phase: So long as the source has a next element, return the match.
ListChunk <Pair <TRightInput, TRightKey> > currentRightChunk = mutables._currentRightMatches;
if (currentRightChunk != null && mutables._currentRightMatchesIndex == currentRightChunk.Count)
{
mutables._currentRightMatches = currentRightChunk.Next;
mutables._currentRightMatchesIndex = 0;
}
if (mutables._currentRightMatches == null)
{
// We have to look up the next list of matches in the hash-table.
Pair <TLeftInput, THashKey> leftPair = default(Pair <TLeftInput, THashKey>);
TLeftKey leftKey = default(TLeftKey);
while (_leftSource.MoveNext(ref leftPair, ref leftKey))
{
if ((mutables._outputLoopCount++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
// Find the match in the hash table.
HashLookupValueList <TRightInput, TRightKey> matchValue = default(HashLookupValueList <TRightInput, TRightKey>);
TLeftInput leftElement = leftPair.First;
THashKey leftHashKey = leftPair.Second;
// Ignore null keys.
if (leftHashKey != null)
{
if (mutables._rightHashLookup.TryGetValue(leftHashKey, ref matchValue))
{
// We found a new match. We remember the list in case there are multiple
// values under this same key -- the next iteration will pick them up.
mutables._currentRightMatches = matchValue.Tail;
Debug.Assert(mutables._currentRightMatches == null || mutables._currentRightMatches.Count > 0,
"we were expecting that the list would be either null or empty");
mutables._currentRightMatchesIndex = 0;
// Yield the value.
currentElement = _resultSelector(leftElement, matchValue.Head.First);
currentKey = _outputKeyBuilder.Combine(leftKey, matchValue.Head.Second);
// If there is a list of matches, remember the left values for next time.
if (matchValue.Tail != null)
{
mutables._currentLeft = leftElement;
mutables._currentLeftKey = leftKey;
}
return(true);
}
}
}
// If we've reached the end of the data source, we're done.
return(false);
}
// Produce the next element.
Debug.Assert(mutables._currentRightMatches != null);
Debug.Assert(0 <= mutables._currentRightMatchesIndex && mutables._currentRightMatchesIndex < mutables._currentRightMatches.Count);
Pair <TRightInput, TRightKey> rightMatch = mutables._currentRightMatches._chunk[mutables._currentRightMatchesIndex];
currentElement = _resultSelector(mutables._currentLeft, rightMatch.First);
currentKey = _outputKeyBuilder.Combine(mutables._currentLeftKey, rightMatch.Second);
mutables._currentRightMatchesIndex++;
return(true);
}
//---------------------------------------------------------------------------------------
// Called when this enumerator is first enumerated; it must walk through the source
// and redistribute elements to their slot in the exchange matrix.
//
private void EnumerateAndRedistributeElements()
{
Mutables mutables = _mutables;
Debug.Assert(mutables != null);
ListChunk <Pair>[] privateBuffers = new ListChunk <Pair> [_partitionCount];
TInputOutput element = default(TInputOutput);
TIgnoreKey ignoreKey = default(TIgnoreKey);
int loopCount = 0;
while (_source.MoveNext(ref element, ref ignoreKey))
{
if ((loopCount++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
// Calculate the element's destination partition index, placing it into the
// appropriate buffer from which partitions will later enumerate.
int destinationIndex;
THashKey elementHashKey = default(THashKey);
if (_keySelector != null)
{
elementHashKey = _keySelector(element);
destinationIndex = _repartitionStream.GetHashCode(elementHashKey) % _partitionCount;
}
else
{
Debug.Assert(typeof(THashKey) == typeof(NoKeyMemoizationRequired));
destinationIndex = _repartitionStream.GetHashCode(element) % _partitionCount;
}
Debug.Assert(0 <= destinationIndex && destinationIndex < _partitionCount,
"destination partition outside of the legal range of partitions");
// Get the buffer for the destination partition, lazily allocating if needed. We maintain
// this list in our own private cache so that we avoid accessing shared memory locations
// too much. In the original implementation, we'd access the buffer in the matrix ([N,M],
// where N is the current partition and M is the destination), but some rudimentary
// performance profiling indicates copying at the end performs better.
ListChunk <Pair> buffer = privateBuffers[destinationIndex];
if (buffer == null)
{
const int INITIAL_PRIVATE_BUFFER_SIZE = 128;
privateBuffers[destinationIndex] = buffer = new ListChunk <Pair>(INITIAL_PRIVATE_BUFFER_SIZE);
}
buffer.Add(new Pair(element, elementHashKey));
}
// Copy the local buffers to the shared space and then signal to other threads that
// we are done. We can then immediately move on to enumerating the elements we found
// for the current partition before waiting at the barrier. If we found a lot, we will
// hopefully never have to physically wait.
for (int i = 0; i < _partitionCount; i++)
{
_valueExchangeMatrix[_partitionIndex][i] = privateBuffers[i];
}
_barrier.Signal();
// Begin at our own buffer.
mutables._currentBufferIndex = _partitionIndex;
mutables._currentBuffer = privateBuffers[_partitionIndex];
mutables._currentIndex = ENUMERATION_NOT_STARTED;
}
//---------------------------------------------------------------------------------------
// MoveNext implements all the hash-join logic noted earlier. When it is called first, it
// will execute the entire inner query tree, and build a hash-table lookup. This is the
// Building phase. Then for the first call and all subsequent calls to MoveNext, we will
// incrementally perform the Probing phase. We'll keep getting elements from the outer
// data source, looking into the hash-table we built, and enumerating the full results.
//
// This routine supports both inner and outer (group) joins. An outer join will yield a
// (possibly empty) list of matching elements from the inner instead of one-at-a-time,
// as we do for inner joins.
//
internal override bool MoveNext(ref TOutput currentElement, ref TLeftKey currentKey)
{
Contract.Assert(_singleResultSelector != null || _groupResultSelector != null, "expected a compiled result selector");
Contract.Assert(_leftSource != null);
Contract.Assert(_rightSource != null);
// BUILD phase: If we haven't built the hash-table yet, create that first.
Mutables mutables = _mutables;
if (mutables == null)
{
mutables = _mutables = new Mutables();
#if DEBUG
int hashLookupCount = 0;
int hashKeyCollisions = 0;
#endif
mutables._rightHashLookup = new HashLookup <THashKey, Pair>(_keyComparer);
Pair rightPair = new Pair(default(TRightInput), default(THashKey));
int rightKeyUnused = default(int);
int i = 0;
while (_rightSource.MoveNext(ref rightPair, ref rightKeyUnused))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
TRightInput rightElement = (TRightInput)rightPair.First;
THashKey rightHashKey = (THashKey)rightPair.Second;
// We ignore null keys.
if (rightHashKey != null)
{
#if DEBUG
hashLookupCount++;
#endif
// See if we've already stored an element under the current key. If not, we
// lazily allocate a pair to hold the elements mapping to the same key.
const int INITIAL_CHUNK_SIZE = 2;
Pair currentValue = new Pair(default(TRightInput), default(ListChunk <TRightInput>));
if (!mutables._rightHashLookup.TryGetValue(rightHashKey, ref currentValue))
{
currentValue = new Pair(rightElement, null);
if (_groupResultSelector != null)
{
// For group joins, we also add the element to the list. This makes
// it easier later to yield the list as-is.
currentValue.Second = new ListChunk <TRightInput>(INITIAL_CHUNK_SIZE);
((ListChunk <TRightInput>)currentValue.Second).Add((TRightInput)rightElement);
}
mutables._rightHashLookup.Add(rightHashKey, currentValue);
}
else
{
if (currentValue.Second == null)
{
// Lazily allocate a list to hold all but the 1st value. We need to
// re-store this element because the pair is a value type.
currentValue.Second = new ListChunk <TRightInput>(INITIAL_CHUNK_SIZE);
mutables._rightHashLookup[rightHashKey] = currentValue;
}
((ListChunk <TRightInput>)currentValue.Second).Add((TRightInput)rightElement);
#if DEBUG
hashKeyCollisions++;
#endif
}
}
}
#if DEBUG
TraceHelpers.TraceInfo("ParallelJoinQueryOperator::MoveNext - built hash table [count = {0}, collisions = {1}]",
hashLookupCount, hashKeyCollisions);
#endif
}
// PROBE phase: So long as the source has a next element, return the match.
ListChunk <TRightInput> currentRightChunk = mutables._currentRightMatches;
if (currentRightChunk != null && mutables._currentRightMatchesIndex == currentRightChunk.Count)
{
currentRightChunk = mutables._currentRightMatches = currentRightChunk.Next;
mutables._currentRightMatchesIndex = 0;
}
if (mutables._currentRightMatches == null)
{
// We have to look up the next list of matches in the hash-table.
Pair leftPair = new Pair(default(TLeftInput), default(THashKey));
TLeftKey leftKey = default(TLeftKey);
while (_leftSource.MoveNext(ref leftPair, ref leftKey))
{
if ((mutables._outputLoopCount++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
// Find the match in the hash table.
Pair matchValue = new Pair(default(TRightInput), default(ListChunk <TRightInput>));
TLeftInput leftElement = (TLeftInput)leftPair.First;
THashKey leftHashKey = (THashKey)leftPair.Second;
// Ignore null keys.
if (leftHashKey != null)
{
if (mutables._rightHashLookup.TryGetValue(leftHashKey, ref matchValue))
{
// We found a new match. For inner joins, we remember the list in case
// there are multiple value under this same key -- the next iteration will pick
// them up. For outer joins, we will use the list momentarily.
if (_singleResultSelector != null)
{
mutables._currentRightMatches = (ListChunk <TRightInput>)matchValue.Second;
Contract.Assert(mutables._currentRightMatches == null || mutables._currentRightMatches.Count > 0,
"we were expecting that the list would be either null or empty");
mutables._currentRightMatchesIndex = 0;
// Yield the value.
currentElement = _singleResultSelector(leftElement, (TRightInput)matchValue.First);
currentKey = leftKey;
// If there is a list of matches, remember the left values for next time.
if (matchValue.Second != null)
{
mutables._currentLeft = leftElement;
mutables._currentLeftKey = leftKey;
}
return(true);
}
}
}
// For outer joins, we always yield a result.
if (_groupResultSelector != null)
{
// Grab the matches, or create an empty list if there are none.
IEnumerable <TRightInput> matches = (ListChunk <TRightInput>)matchValue.Second;
if (matches == null)
{
matches = ParallelEnumerable.Empty <TRightInput>();
}
// Generate the current value.
currentElement = _groupResultSelector(leftElement, matches);
currentKey = leftKey;
return(true);
}
}
// If we've reached the end of the data source, we're done.
return(false);
}
// Produce the next element and increment our index within the matches.
Contract.Assert(_singleResultSelector != null);
Contract.Assert(mutables._currentRightMatches != null);
Contract.Assert(0 <= mutables._currentRightMatchesIndex && mutables._currentRightMatchesIndex < mutables._currentRightMatches.Count);
currentElement = _singleResultSelector(
mutables._currentLeft, mutables._currentRightMatches._chunk[mutables._currentRightMatchesIndex]);
currentKey = mutables._currentLeftKey;
mutables._currentRightMatchesIndex++;
return(true);
}
//---------------------------------------------------------------------------------------
// Walks the two data sources, left and then right, to produce the intersection.
//
internal override bool MoveNext(ref TInputOutput currentElement, ref TLeftKey currentKey)
{
Contract.Assert(m_leftSource != null);
Contract.Assert(m_rightSource != null);
// Build the set out of the left data source, if we haven't already.
int i = 0;
if (m_hashLookup == null)
{
// @TODO: @PERF: @BUG#594: different implementation of set operations. Consider a treap.
m_hashLookup = new Dictionary <Wrapper <TInputOutput>, Pair <TInputOutput, TLeftKey> >(m_comparer);
Pair <TInputOutput, NoKeyMemoizationRequired> leftElement = default(Pair <TInputOutput, NoKeyMemoizationRequired>);
TLeftKey leftKey = default(TLeftKey);
while (m_leftSource.MoveNext(ref leftElement, ref leftKey))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(m_cancellationToken);
}
// For each element, we track the smallest order key for that element that we saw so far
Pair <TInputOutput, TLeftKey> oldEntry;
Wrapper <TInputOutput> wrappedLeftElem = new Wrapper <TInputOutput>(leftElement.First);
// If this is the first occurence of this element, or the order key is lower than all keys we saw previously,
// update the order key for this element.
if (!m_hashLookup.TryGetValue(wrappedLeftElem, out oldEntry) || m_leftKeyComparer.Compare(leftKey, oldEntry.Second) < 0)
{
// For each "elem" value, we store the smallest key, and the element value that had that key.
// Note that even though two element values are "equal" according to the EqualityComparer,
// we still cannot choose arbitrarily which of the two to yield.
m_hashLookup[wrappedLeftElem] = new Pair <TInputOutput, TLeftKey>(leftElement.First, leftKey);
}
}
}
// Now iterate over the right data source, looking for matches.
Pair <TInputOutput, NoKeyMemoizationRequired> rightElement = default(Pair <TInputOutput, NoKeyMemoizationRequired>);
int rightKeyUnused = default(int);
while (m_rightSource.MoveNext(ref rightElement, ref rightKeyUnused))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(m_cancellationToken);
}
// If we found the element in our set, and if we haven't returned it yet,
// we can yield it to the caller. We also mark it so we know we've returned
// it once already and never will again.
Pair <TInputOutput, TLeftKey> entry;
Wrapper <TInputOutput> wrappedRightElem = new Wrapper <TInputOutput>(rightElement.First);
if (m_hashLookup.TryGetValue(wrappedRightElem, out entry))
{
currentElement = entry.First;
currentKey = entry.Second;
// @TODO: @PERF: avoid the double lookup required to remove the element
// we have already found in the hashtable.
m_hashLookup.Remove(new Wrapper <TInputOutput>(entry.First));
return(true);
}
}
return(false);
}
private void MergeSortCooperatively()
{
CancellationToken mergedCancellationToken = this.m_groupState.CancellationState.MergedCancellationToken;
int length = this.m_sharedBarriers.GetLength(0);
for (int i = 0; i < length; i++)
{
bool flag = i == (length - 1);
int num3 = this.ComputePartnerIndex(i);
if (num3 < this.m_partitionCount)
{
int[] numArray = this.m_sharedIndices[this.m_partitionIndex];
GrowingArray <TKey> array = this.m_sharedKeys[this.m_partitionIndex];
TKey[] internalArray = array.InternalArray;
TInputOutput[] sourceArray = this.m_sharedValues[this.m_partitionIndex];
this.m_sharedBarriers[i, Math.Min(this.m_partitionIndex, num3)].SignalAndWait(mergedCancellationToken);
if (this.m_partitionIndex >= num3)
{
this.m_sharedBarriers[i, num3].SignalAndWait(mergedCancellationToken);
int[] numArray4 = this.m_sharedIndices[this.m_partitionIndex];
TKey[] localArray6 = this.m_sharedKeys[this.m_partitionIndex].InternalArray;
TInputOutput[] localArray7 = this.m_sharedValues[this.m_partitionIndex];
int[] numArray5 = this.m_sharedIndices[num3];
GrowingArray <TKey> array2 = this.m_sharedKeys[num3];
TInputOutput[] localArray8 = this.m_sharedValues[num3];
int destinationIndex = localArray7.Length;
int num12 = sourceArray.Length;
int num13 = destinationIndex + num12;
int num14 = (num13 + 1) / 2;
int num15 = num13 - 1;
int num16 = destinationIndex - 1;
int num17 = num12 - 1;
while (num15 >= num14)
{
if ((num15 & 0x3f) == 0)
{
CancellationState.ThrowIfCanceled(mergedCancellationToken);
}
if ((num16 >= 0) && ((num17 < 0) || (this.m_keyComparer.Compare(localArray6[numArray4[num16]], internalArray[numArray[num17]]) > 0)))
{
if (flag)
{
localArray8[num15] = localArray7[numArray4[num16]];
}
else
{
numArray5[num15] = numArray4[num16];
}
num16--;
}
else
{
if (flag)
{
localArray8[num15] = sourceArray[numArray[num17]];
}
else
{
numArray5[num15] = destinationIndex + numArray[num17];
}
num17--;
}
num15--;
}
if (!flag && (sourceArray.Length > 0))
{
array2.CopyFrom(internalArray, sourceArray.Length);
Array.Copy(sourceArray, 0, localArray8, destinationIndex, sourceArray.Length);
}
this.m_sharedBarriers[i, num3].SignalAndWait(mergedCancellationToken);
return;
}
int[] numArray2 = this.m_sharedIndices[num3];
TKey[] localArray3 = this.m_sharedKeys[num3].InternalArray;
TInputOutput[] localArray4 = this.m_sharedValues[num3];
this.m_sharedIndices[num3] = numArray;
this.m_sharedKeys[num3] = array;
this.m_sharedValues[num3] = sourceArray;
int num4 = sourceArray.Length;
int num5 = localArray4.Length;
int num6 = num4 + num5;
int[] numArray3 = null;
TInputOutput[] destinationArray = new TInputOutput[num6];
if (!flag)
{
numArray3 = new int[num6];
}
this.m_sharedIndices[this.m_partitionIndex] = numArray3;
this.m_sharedKeys[this.m_partitionIndex] = array;
this.m_sharedValues[this.m_partitionIndex] = destinationArray;
this.m_sharedBarriers[i, this.m_partitionIndex].SignalAndWait(mergedCancellationToken);
int num7 = (num6 + 1) / 2;
int index = 0;
int num9 = 0;
int num10 = 0;
while (index < num7)
{
if ((index & 0x3f) == 0)
{
CancellationState.ThrowIfCanceled(mergedCancellationToken);
}
if ((num9 < num4) && ((num10 >= num5) || (this.m_keyComparer.Compare(internalArray[numArray[num9]], localArray3[numArray2[num10]]) <= 0)))
{
if (flag)
{
destinationArray[index] = sourceArray[numArray[num9]];
}
else
{
numArray3[index] = numArray[num9];
}
num9++;
}
else
{
if (flag)
{
destinationArray[index] = localArray4[numArray2[num10]];
}
else
{
numArray3[index] = num4 + numArray2[num10];
}
num10++;
}
index++;
}
if (!flag && (num4 > 0))
{
Array.Copy(sourceArray, 0, destinationArray, 0, num4);
}
this.m_sharedBarriers[i, this.m_partitionIndex].SignalAndWait(mergedCancellationToken);
}
}
}
internal PartitionedStreamMerger(bool forEffectMerge, ParallelMergeOptions mergeOptions, TaskScheduler taskScheduler, bool outputOrdered, CancellationState cancellationState, int queryId)
{
this.m_forEffectMerge = forEffectMerge;
this.m_mergeOptions = mergeOptions;
this.m_isOrdered = outputOrdered;
this.m_taskScheduler = taskScheduler;
this.m_cancellationState = cancellationState;
this.m_queryId = queryId;
}
internal override bool MoveNext(ref TResult currentElement, ref int currentKey)
{
if ((this.m_buffer == null) && (this.m_count > 0))
{
List <Pair <TResult, int> > list = new List <Pair <TResult, int> >();
TResult local = default(TResult);
int num = 0;
int num2 = 0;
while ((list.Count < this.m_count) && this.m_source.MoveNext(ref local, ref num))
{
if ((num2++ & 0x3f) == 0)
{
CancellationState.ThrowIfCanceled(this.m_cancellationToken);
}
list.Add(new Pair <TResult, int>(local, num));
lock (this.m_sharedIndices)
{
if (!this.m_sharedIndices.Insert(num))
{
break;
}
continue;
}
}
this.m_sharedBarrier.Signal();
this.m_sharedBarrier.Wait(this.m_cancellationToken);
this.m_buffer = list;
this.m_bufferIndex = new Shared <int>(-1);
}
if (this.m_take)
{
if ((this.m_count == 0) || (this.m_bufferIndex.Value >= (this.m_buffer.Count - 1)))
{
return(false);
}
this.m_bufferIndex.Value += 1;
Pair <TResult, int> pair = this.m_buffer[this.m_bufferIndex.Value];
currentElement = pair.First;
Pair <TResult, int> pair2 = this.m_buffer[this.m_bufferIndex.Value];
currentKey = pair2.Second;
int maxValue = this.m_sharedIndices.MaxValue;
if (maxValue != -1)
{
Pair <TResult, int> pair3 = this.m_buffer[this.m_bufferIndex.Value];
return(pair3.Second <= maxValue);
}
return(true);
}
int num4 = -1;
if (this.m_count > 0)
{
if (this.m_sharedIndices.Count < this.m_count)
{
return(false);
}
num4 = this.m_sharedIndices.MaxValue;
if (this.m_bufferIndex.Value < (this.m_buffer.Count - 1))
{
this.m_bufferIndex.Value += 1;
while (this.m_bufferIndex.Value < this.m_buffer.Count)
{
Pair <TResult, int> pair4 = this.m_buffer[this.m_bufferIndex.Value];
if (pair4.Second > num4)
{
Pair <TResult, int> pair5 = this.m_buffer[this.m_bufferIndex.Value];
currentElement = pair5.First;
Pair <TResult, int> pair6 = this.m_buffer[this.m_bufferIndex.Value];
currentKey = pair6.Second;
return(true);
}
this.m_bufferIndex.Value += 1;
}
}
}
return(this.m_source.MoveNext(ref currentElement, ref currentKey));
}
//---------------------------------------------------------------------------------------
// Walks the two data sources, left and then right, to produce the union.
//
internal override bool MoveNext(ref TInputOutput currentElement, ref ConcatKey <TLeftKey, TRightKey> currentKey)
{
Contract.Assert(m_leftSource != null);
Contract.Assert(m_rightSource != null);
if (m_outputEnumerator == null)
{
IEqualityComparer <Wrapper <TInputOutput> > wrapperComparer = new WrapperEqualityComparer <TInputOutput>(m_comparer);
Dictionary <Wrapper <TInputOutput>, Pair <TInputOutput, ConcatKey <TLeftKey, TRightKey> > > union =
new Dictionary <Wrapper <TInputOutput>, Pair <TInputOutput, ConcatKey <TLeftKey, TRightKey> > >(wrapperComparer);
Pair <TInputOutput, NoKeyMemoizationRequired> elem = default(Pair <TInputOutput, NoKeyMemoizationRequired>);
TLeftKey leftKey = default(TLeftKey);
int i = 0;
while (m_leftSource.MoveNext(ref elem, ref leftKey))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(m_cancellationToken);
}
ConcatKey <TLeftKey, TRightKey> key =
ConcatKey <TLeftKey, TRightKey> .MakeLeft(m_leftOrdered?leftKey : default(TLeftKey));
Pair <TInputOutput, ConcatKey <TLeftKey, TRightKey> > oldEntry;
Wrapper <TInputOutput> wrappedElem = new Wrapper <TInputOutput>(elem.First);
if (!union.TryGetValue(wrappedElem, out oldEntry) || m_keyComparer.Compare(key, oldEntry.Second) < 0)
{
union[wrappedElem] = new Pair <TInputOutput, ConcatKey <TLeftKey, TRightKey> >(elem.First, key);
}
}
TRightKey rightKey = default(TRightKey);
while (m_rightSource.MoveNext(ref elem, ref rightKey))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(m_cancellationToken);
}
ConcatKey <TLeftKey, TRightKey> key =
ConcatKey <TLeftKey, TRightKey> .MakeRight(m_rightOrdered?rightKey : default(TRightKey));
Pair <TInputOutput, ConcatKey <TLeftKey, TRightKey> > oldEntry;
Wrapper <TInputOutput> wrappedElem = new Wrapper <TInputOutput>(elem.First);
if (!union.TryGetValue(wrappedElem, out oldEntry) || m_keyComparer.Compare(key, oldEntry.Second) < 0)
{
union[wrappedElem] = new Pair <TInputOutput, ConcatKey <TLeftKey, TRightKey> >(elem.First, key);;
}
}
m_outputEnumerator = union.GetEnumerator();
}
if (m_outputEnumerator.MoveNext())
{
Pair <TInputOutput, ConcatKey <TLeftKey, TRightKey> > current = m_outputEnumerator.Current.Value;
currentElement = current.First;
currentKey = current.Second;
return(true);
}
return(false);
}
internal DefaultMergeHelper(PartitionedStream <TInputOutput, TIgnoreKey> partitions, bool ignoreOutput, ParallelMergeOptions options, TaskScheduler taskScheduler, CancellationState cancellationState, int queryId)
{
this.m_taskGroupState = new QueryTaskGroupState(cancellationState, queryId);
this.m_partitions = partitions;
this.m_taskScheduler = taskScheduler;
this.m_ignoreOutput = ignoreOutput;
if (!ignoreOutput)
{
if (options != ParallelMergeOptions.FullyBuffered)
{
if (partitions.PartitionCount > 1)
{
this.m_asyncChannels = MergeExecutor <TInputOutput> .MakeAsynchronousChannels(partitions.PartitionCount, options, cancellationState.MergedCancellationToken);
this.m_channelEnumerator = new AsynchronousChannelMergeEnumerator <TInputOutput>(this.m_taskGroupState, this.m_asyncChannels);
}
else
{
this.m_channelEnumerator = ExceptionAggregator.WrapQueryEnumerator <TInputOutput, TIgnoreKey>(partitions[0], this.m_taskGroupState.CancellationState).GetEnumerator();
}
}
else
{
this.m_syncChannels = MergeExecutor <TInputOutput> .MakeSynchronousChannels(partitions.PartitionCount);
this.m_channelEnumerator = new SynchronousChannelMergeEnumerator <TInputOutput>(this.m_taskGroupState, this.m_syncChannels);
}
}
}
//---------------------------------------------------------------------------------------
// Straightforward IEnumerator<T> methods.
//
internal override bool MoveNext(ref TSource currentElement, ref int currentKey)
{
Contract.Assert(m_source != null);
if (m_alreadySearched)
{
return(false);
}
// Look for the lowest element.
TSource candidate = default(TSource);
int candidateIndex = -1;
try
{
int key = default(int);
int i = 0;
while (m_source.MoveNext(ref candidate, ref key))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(m_cancellationToken);
}
// If the predicate is null or the current element satisfies it, we have found the
// current partition's "candidate" for the first element. Note it.
if (m_predicate == null || m_predicate(candidate))
{
candidateIndex = key;
// Try to swap our index with the shared one, so long as it's smaller.
int observedSharedIndex;
do
{
observedSharedIndex = m_sharedFirstCandidate.Value;
} while ((observedSharedIndex == -1 || candidateIndex < observedSharedIndex) &&
Interlocked.CompareExchange(ref m_sharedFirstCandidate.Value, candidateIndex, observedSharedIndex) != observedSharedIndex);
break;
}
else if (m_sharedFirstCandidate.Value != -1 && key > m_sharedFirstCandidate.Value)
{
// We've scanned past another partition's best element. Bail.
break;
}
}
}
finally
{
// No matter whether we exit due to an exception or normal completion, we must ensure
// that we signal other partitions that we have completed. Otherwise, we can cause deadlocks.
m_sharedBarrier.Signal();
}
m_alreadySearched = true;
// Only if we might be a candidate do we wait.
if (candidateIndex != -1)
{
m_sharedBarrier.Wait(m_cancellationToken);
// Now re-read the shared index. If it's the same as ours, we won and return true.
if (m_sharedFirstCandidate.Value == candidateIndex)
{
currentElement = candidate;
currentKey = 0; // 1st (and only) element, so we hardcode the output index to 0.
return(true);
}
}
// If we got here, we didn't win. Return false.
return(false);
}
//---------------------------------------------------------------------------------------
// Straightforward IEnumerator<T> methods.
//
internal override bool MoveNext(ref TResult currentElement, ref int currentKey)
{
// If the buffer has not been created, we will generate it lazily on demand.
if (m_buffer == null)
{
// Create a buffer, but don't publish it yet (in case of exception).
List <Pair <TResult, int> > buffer = new List <Pair <TResult, int> >();
// Enter the search phase. In this phase, we scan the input until one of three
// things happens: (1) all input has been exhausted, (2) the predicate yields
// false for one of our elements, or (3) we move past the current lowest index
// found by other partitions for a false element. As we go, we have to remember
// the elements by placing them into the buffer.
// @TODO: @BUG#595: should we integrate these kinds of loops with cancelation due to exceptions?
try
{
TResult current = default(TResult);
int index = default(int);
int i = 0; //counter to help with cancellation
while (m_source.MoveNext(ref current, ref index))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(m_cancellationToken);
}
// Add the current element to our buffer.
// @TODO: @PERF: @BUG#414: some day we can optimize this, e.g. if the input is an array,
// we can always just rescan it later. Could expose this via a "Reset" mechanism.
buffer.Add(new Pair <TResult, int>(current, index));
// See if another partition has found a false value before this element. If so,
// we should stop scanning the input now and reach the barrier ASAP.
int currentLowIndex = m_sharedLowFalse.Value;
if (currentLowIndex != -1 && index > currentLowIndex)
{
break;
}
// Evaluate the predicate, either indexed or not based on info passed to the ctor.
bool predicateResult;
if (m_predicate != null)
{
predicateResult = m_predicate(current);
}
else
{
Contract.Assert(m_indexedPredicate != null);
predicateResult = m_indexedPredicate(current, index);
}
if (!predicateResult)
{
// Signal that we've found a false element, racing with other partitions to
// set the shared index value. If we lose this race, that's fine: the one trying
// to publish the lowest value will ultimately win; so we retry if ours is
// lower, or bail right away otherwise. We use a spin wait to deal with contention.
int observedLowIndex;
SpinWait s = new SpinWait();
while (true)
{
// Read the current value of the index with a volatile load to prevent movement.
observedLowIndex = Thread.VolatileRead(ref m_sharedLowFalse.Value);
// If the current shared index is set and lower than ours, we won't try to CAS.
if ((observedLowIndex != -1 && observedLowIndex < index) ||
Interlocked.CompareExchange(ref m_sharedLowFalse.Value, index, observedLowIndex) == observedLowIndex)
{
// Either the current value is lower or we succeeded in swapping the
// current value with ours. We're done.
break;
}
// If we failed the swap, we will spin briefly to reduce contention.
s.SpinOnce();
}
// Exit the loop and reach the barrier.
break;
}
}
}
finally
{
// No matter whether we exit due to an exception or normal completion, we must ensure
// that we signal other partitions that we have completed. Otherwise, we can cause deadlocks.
m_sharedBarrier.Signal();
}
// Before exiting the search phase, we will synchronize with others. This is a barrier.
m_sharedBarrier.Wait(m_cancellationToken);
// Publish the buffer and set the index to just before the 1st element.
m_buffer = buffer;
m_bufferIndex = new Shared <int>(-1);
}
// Now either enter (or continue) the yielding phase. As soon as we reach this, we know the
// current shared "low false" value is the absolute lowest with a false.
if (m_take)
{
// In the case of a take-while, we will yield each element from our buffer for which
// the element is lesser than the lowest false index found.
if (m_bufferIndex.Value >= m_buffer.Count - 1)
{
return(false);
}
// Increment the index, and remember the values.
++m_bufferIndex.Value;
currentElement = m_buffer[m_bufferIndex.Value].First;
currentKey = m_buffer[m_bufferIndex.Value].Second;
return(m_sharedLowFalse.Value == -1 ||
m_sharedLowFalse.Value > m_buffer[m_bufferIndex.Value].Second);
}
else
{
// If no false was found, the output is empty.
if (m_sharedLowFalse.Value == -1)
{
return(false);
}
// In the case of a skip-while, we must skip over elements whose index is lesser than the
// lowest index found. Once we've exhausted the buffer, we must go back and continue
// enumerating the data source until it is empty.
if (m_bufferIndex.Value < m_buffer.Count - 1)
{
for (m_bufferIndex.Value++; m_bufferIndex.Value < m_buffer.Count; m_bufferIndex.Value++)
{
// If the current buffered element's index is greater than or equal to the smallest
// false index found, we will yield it as a result.
if (m_buffer[m_bufferIndex.Value].Second >= m_sharedLowFalse.Value)
{
currentElement = m_buffer[m_bufferIndex.Value].First;
currentKey = m_buffer[m_bufferIndex.Value].Second;
return(true);
}
}
}
// Lastly, so long as our input still has elements, they will be yieldable.
if (m_source.MoveNext(ref currentElement, ref currentKey))
{
Contract.Assert(currentKey > m_sharedLowFalse.Value,
"expected remaining element indices to be greater than smallest");
return(true);
}
}
return(false);
}
//---------------------------------------------------------------------------------------
// Straightforward IEnumerator<T> methods.
//
internal override bool MoveNext(ref TResult currentElement, ref int currentKey)
{
Contract.Assert(m_sharedIndices != null);
// If the buffer has not been created, we will populate it lazily on demand.
if (m_buffer == null && m_count > 0)
{
// Create a buffer, but don't publish it yet (in case of exception).
List <Pair <TResult, int> > buffer = new List <Pair <TResult, int> >();
// Enter the search phase. In this phase, all partitions race to populate
// the shared indices with their first 'count' contiguous elements.
TResult current = default(TResult);
int index = default(int);
int i = 0; //counter to help with cancellation
while (buffer.Count < m_count && m_source.MoveNext(ref current, ref index))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(m_cancellationToken);
}
// Add the current element to our buffer.
// @TODO: @PERF: @BUG#414: some day we can optimize this, e.g. if the input is an array,
// we can always just rescan it later. Could expose this via a "Reset" mechanism.
buffer.Add(new Pair <TResult, int>(current, index));
// Now we will try to insert our index into the shared indices list, quitting if
// our index is greater than all of the indices already inside it.
lock (m_sharedIndices)
{
if (!m_sharedIndices.Insert(index))
{
// We have read past the maximum index. We can move to the barrier now.
break;
}
}
}
// Before exiting the search phase, we will synchronize with others. This is a barrier.
m_sharedBarrier.Signal();
m_sharedBarrier.Wait(m_cancellationToken);
// Publish the buffer and set the index to just before the 1st element.
m_buffer = buffer;
m_bufferIndex = new Shared <int>(-1);
}
// Now either enter (or continue) the yielding phase. As soon as we reach this, we know the
// index of the 'count'-th input element.
if (m_take)
{
// In the case of a Take, we will yield each element from our buffer for which
// the element is lesser than the 'count'-th index found.
if (m_count == 0 || m_bufferIndex.Value >= m_buffer.Count - 1)
{
return(false);
}
// Increment the index, and remember the values.
++m_bufferIndex.Value;
currentElement = m_buffer[m_bufferIndex.Value].First;
currentKey = m_buffer[m_bufferIndex.Value].Second;
// Only yield the element if its index is less than or equal to the max index.
int maxIndex = m_sharedIndices.MaxValue;
return(maxIndex == -1 || m_buffer[m_bufferIndex.Value].Second <= maxIndex);
}
else
{
int minIndex = -1;
// If the count to skip was greater than 0, look at the buffer.
if (m_count > 0)
{
// If there wasn't enough input to skip, return right away.
if (m_sharedIndices.Count < m_count)
{
return(false);
}
minIndex = m_sharedIndices.MaxValue;
// In the case of a skip, we must skip over elements whose index is lesser than the
// 'count'-th index found. Once we've exhausted the buffer, we must go back and continue
// enumerating the data source until it is empty.
if (m_bufferIndex.Value < m_buffer.Count - 1)
{
for (m_bufferIndex.Value++; m_bufferIndex.Value < m_buffer.Count; m_bufferIndex.Value++)
{
// If the current buffered element's index is greater than the 'count'-th index,
// we will yield it as a result.
if (m_buffer[m_bufferIndex.Value].Second > minIndex)
{
currentElement = m_buffer[m_bufferIndex.Value].First;
currentKey = m_buffer[m_bufferIndex.Value].Second;
return(true);
}
}
}
}
// Lastly, so long as our input still has elements, they will be yieldable.
if (m_source.MoveNext(ref currentElement, ref currentKey))
{
Contract.Assert(currentKey > minIndex,
"expected remaining element indices to be greater than smallest");
return(true);
}
}
return(false);
}
internal static MergeExecutor <TInputOutput> Execute <TKey>(PartitionedStream <TInputOutput, TKey> partitions, bool ignoreOutput, ParallelMergeOptions options, TaskScheduler taskScheduler, bool isOrdered, CancellationState cancellationState, int queryId)
{
MergeExecutor <TInputOutput> executor = new MergeExecutor <TInputOutput>();
if (isOrdered && !ignoreOutput)
{
if ((options != ParallelMergeOptions.FullyBuffered) && !partitions.OrdinalIndexState.IsWorseThan(OrdinalIndexState.Increasing))
{
bool autoBuffered = options == ParallelMergeOptions.AutoBuffered;
if (partitions.PartitionCount > 1)
{
executor.m_mergeHelper = new OrderPreservingPipeliningMergeHelper <TInputOutput>((PartitionedStream <TInputOutput, int>)partitions, taskScheduler, cancellationState, autoBuffered, queryId);
}
else
{
executor.m_mergeHelper = new DefaultMergeHelper <TInputOutput, TKey>(partitions, false, options, taskScheduler, cancellationState, queryId);
}
}
else
{
executor.m_mergeHelper = new OrderPreservingMergeHelper <TInputOutput, TKey>(partitions, taskScheduler, cancellationState, queryId);
}
}
else
{
executor.m_mergeHelper = new DefaultMergeHelper <TInputOutput, TKey>(partitions, ignoreOutput, options, taskScheduler, cancellationState, queryId);
}
executor.Execute();
return(executor);
}
//-----------------------------------------------------------------------------------
// Constructs a new settings structure.
//
internal QuerySettings(TaskScheduler taskScheduler, int? degreeOfParallelism,
CancellationToken externalCancellationToken, ParallelExecutionMode? executionMode,
ParallelMergeOptions? mergeOptions)
{
_taskScheduler = taskScheduler;
_degreeOfParallelism = degreeOfParallelism;
_cancellationState = new CancellationState(externalCancellationToken);
_executionMode = executionMode;
_mergeOptions = mergeOptions;
_queryId = -1;
Contract.Assert(_cancellationState != null);
}
//---------------------------------------------------------------------------------------
// Walks the two data sources, left and then right, to produce the distinct set
//
internal override bool MoveNext(ref TInputOutput currentElement, ref TLeftKey currentKey)
{
Debug.Assert(_leftSource != null);
Debug.Assert(_rightSource != null);
// Build the set out of the left data source, if we haven't already.
if (_outputEnumerator == null)
{
Set <TInputOutput> rightLookup = new Set <TInputOutput>(_comparer);
Pair <TInputOutput, NoKeyMemoizationRequired> rightElement = default(Pair <TInputOutput, NoKeyMemoizationRequired>);
int rightKeyUnused = default(int);
int i = 0;
while (_rightSource.MoveNext(ref rightElement, ref rightKeyUnused))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
rightLookup.Add(rightElement.First);
}
var leftLookup =
new Dictionary <Wrapper <TInputOutput>, Pair <TInputOutput, TLeftKey> >(
new WrapperEqualityComparer <TInputOutput>(_comparer));
Pair <TInputOutput, NoKeyMemoizationRequired> leftElement = default(Pair <TInputOutput, NoKeyMemoizationRequired>);
TLeftKey leftKey = default(TLeftKey);
while (_leftSource.MoveNext(ref leftElement, ref leftKey))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
if (rightLookup.Contains(leftElement.First))
{
continue;
}
Pair <TInputOutput, TLeftKey> oldEntry;
Wrapper <TInputOutput> wrappedLeftElement = new Wrapper <TInputOutput>(leftElement.First);
if (!leftLookup.TryGetValue(wrappedLeftElement, out oldEntry) || _leftKeyComparer.Compare(leftKey, oldEntry.Second) < 0)
{
// For each "elem" value, we store the smallest key, and the element value that had that key.
// Note that even though two element values are "equal" according to the EqualityComparer,
// we still cannot choose arbitrarily which of the two to yield.
leftLookup[wrappedLeftElement] = new Pair <TInputOutput, TLeftKey>(leftElement.First, leftKey);
}
}
_outputEnumerator = leftLookup.GetEnumerator();
}
if (_outputEnumerator.MoveNext())
{
Pair <TInputOutput, TLeftKey> currentPair = _outputEnumerator.Current.Value;
currentElement = currentPair.First;
currentKey = currentPair.Second;
return(true);
}
return(false);
}
//---------------------------------------------------------------------------------------
// Straightforward IEnumerator<T> methods.
//
internal override bool MoveNext(ref TResult currentElement, ref TKey currentKey)
{
Debug.Assert(_sharedIndices != null);
// If the buffer has not been created, we will populate it lazily on demand.
if (_buffer == null && _count > 0)
{
// Create a buffer, but don't publish it yet (in case of exception).
List <Pair> buffer = new List <Pair>();
// Enter the search phase. In this phase, all partitions race to populate
// the shared indices with their first 'count' contiguous elements.
TResult current = default(TResult);
TKey index = default(TKey);
int i = 0; //counter to help with cancellation
while (buffer.Count < _count && _source.MoveNext(ref current, ref index))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
// Add the current element to our buffer.
buffer.Add(new Pair(current, index));
// Now we will try to insert our index into the shared indices list, quitting if
// our index is greater than all of the indices already inside it.
lock (_sharedIndices)
{
if (!_sharedIndices.Insert(index))
{
// We have read past the maximum index. We can move to the barrier now.
break;
}
}
}
// Before exiting the search phase, we will synchronize with others. This is a barrier.
_sharedBarrier.Signal();
_sharedBarrier.Wait(_cancellationToken);
// Publish the buffer and set the index to just before the 1st element.
_buffer = buffer;
_bufferIndex = new Shared <int>(-1);
}
// Now either enter (or continue) the yielding phase. As soon as we reach this, we know the
// index of the 'count'-th input element.
if (_take)
{
// In the case of a Take, we will yield each element from our buffer for which
// the element is lesser than the 'count'-th index found.
if (_count == 0 || _bufferIndex.Value >= _buffer.Count - 1)
{
return(false);
}
// Increment the index, and remember the values.
++_bufferIndex.Value;
currentElement = (TResult)_buffer[_bufferIndex.Value].First;
currentKey = (TKey)_buffer[_bufferIndex.Value].Second;
// Only yield the element if its index is less than or equal to the max index.
return(_sharedIndices.Count == 0 ||
_keyComparer.Compare((TKey)_buffer[_bufferIndex.Value].Second, _sharedIndices.MaxValue) <= 0);
}
else
{
TKey minKey = default(TKey);
// If the count to skip was greater than 0, look at the buffer.
if (_count > 0)
{
// If there wasn't enough input to skip, return right away.
if (_sharedIndices.Count < _count)
{
return(false);
}
minKey = _sharedIndices.MaxValue;
// In the case of a skip, we must skip over elements whose index is lesser than the
// 'count'-th index found. Once we've exhausted the buffer, we must go back and continue
// enumerating the data source until it is empty.
if (_bufferIndex.Value < _buffer.Count - 1)
{
for (_bufferIndex.Value++; _bufferIndex.Value < _buffer.Count; _bufferIndex.Value++)
{
// If the current buffered element's index is greater than the 'count'-th index,
// we will yield it as a result.
if (_keyComparer.Compare((TKey)_buffer[_bufferIndex.Value].Second, minKey) > 0)
{
currentElement = (TResult)_buffer[_bufferIndex.Value].First;
currentKey = (TKey)_buffer[_bufferIndex.Value].Second;
return(true);
}
}
}
}
// Lastly, so long as our input still has elements, they will be yieldable.
if (_source.MoveNext(ref currentElement, ref currentKey))
{
Debug.Assert(_count <= 0 || _keyComparer.Compare(currentKey, minKey) > 0,
"expected remaining element indices to be greater than smallest");
return(true);
}
}
return(false);
}
//---------------------------------------------------------------------------------------
// Straightforward IEnumerator<T> methods.
//
internal override bool MoveNext(ref TSource currentElement, ref int currentKey)
{
Contract.Assert(m_source != null);
if (m_alreadySearched)
{
return(false);
}
// Look for the lowest element.
TSource candidate = default(TSource);
TKey candidateKey = default(TKey);
try
{
TSource value = default(TSource);
TKey key = default(TKey);
int i = 0;
while (m_source.MoveNext(ref value, ref key))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(m_cancellationToken);
}
// If the predicate is null or the current element satisfies it, we have found the
// current partition's "candidate" for the first element. Note it.
if (m_predicate == null || m_predicate(value))
{
candidate = value;
candidateKey = key;
lock (m_operatorState)
{
if (m_operatorState.m_partitionId == -1 || m_keyComparer.Compare(candidateKey, m_operatorState.m_key) < 0)
{
m_operatorState.m_key = candidateKey;
m_operatorState.m_partitionId = m_partitionId;
}
}
break;
}
}
}
finally
{
// No matter whether we exit due to an exception or normal completion, we must ensure
// that we signal other partitions that we have completed. Otherwise, we can cause deadlocks.
m_sharedBarrier.Signal();
}
m_alreadySearched = true;
// Wait only if we may have the result
if (m_partitionId == m_operatorState.m_partitionId)
{
m_sharedBarrier.Wait(m_cancellationToken);
// Now re-read the shared index. If it's the same as ours, we won and return true.
if (m_partitionId == m_operatorState.m_partitionId)
{
currentElement = candidate;
currentKey = 0; // 1st (and only) element, so we hardcode the output index to 0.
return(true);
}
}
// If we got here, we didn't win. Return false.
return(false);
}
//---------------------------------------------------------------------------------------
// Walks the two data sources, left and then right, to produce the union.
//
internal override bool MoveNext(ref TInputOutput currentElement, ref ConcatKey currentKey)
{
Debug.Assert(_leftSource != null);
Debug.Assert(_rightSource != null);
if (_outputEnumerator == null)
{
IEqualityComparer <Wrapper <TInputOutput> > wrapperComparer = new WrapperEqualityComparer <TInputOutput>(_comparer);
Dictionary <Wrapper <TInputOutput>, Pair> union =
new Dictionary <Wrapper <TInputOutput>, Pair>(wrapperComparer);
Pair elem = new Pair(default(TInputOutput), default(NoKeyMemoizationRequired));
TLeftKey leftKey = default(TLeftKey);
int i = 0;
while (_leftSource.MoveNext(ref elem, ref leftKey))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
ConcatKey key =
ConcatKey.MakeLeft <TLeftKey, TRightKey>(_leftOrdered ? leftKey : default(TLeftKey));
Pair oldEntry;
Wrapper <TInputOutput> wrappedElem = new Wrapper <TInputOutput>((TInputOutput)elem.First);
if (!union.TryGetValue(wrappedElem, out oldEntry) || _keyComparer.Compare(key, (ConcatKey)oldEntry.Second) < 0)
{
union[wrappedElem] = new Pair(elem.First, key);
}
}
TRightKey rightKey = default(TRightKey);
while (_rightSource.MoveNext(ref elem, ref rightKey))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
ConcatKey key =
ConcatKey.MakeRight <TLeftKey, TRightKey>(_rightOrdered ? rightKey : default(TRightKey));
Pair oldEntry;
Wrapper <TInputOutput> wrappedElem = new Wrapper <TInputOutput>((TInputOutput)elem.First);
if (!union.TryGetValue(wrappedElem, out oldEntry) || _keyComparer.Compare(key, (ConcatKey)oldEntry.Second) < 0)
{
union[wrappedElem] = new Pair(elem.First, key);;
}
}
_outputEnumerator = union.GetEnumerator();
}
if (_outputEnumerator.MoveNext())
{
Pair current = _outputEnumerator.Current.Value;
currentElement = (TInputOutput)current.First;
currentKey = (ConcatKey)current.Second;
return(true);
}
return(false);
}
internal override bool MoveNext(ref TOutput currentElement, ref TLeftKey currentKey)
{
Mutables <TLeftInput, TLeftKey, TRightInput, THashKey, TOutput> mutables = this.m_mutables;
if (mutables == null)
{
mutables = this.m_mutables = new Mutables <TLeftInput, TLeftKey, TRightInput, THashKey, TOutput>();
mutables.m_rightHashLookup = new HashLookup <THashKey, Pair <TRightInput, ListChunk <TRightInput> > >(this.m_keyComparer);
Pair <TRightInput, THashKey> pair = new Pair <TRightInput, THashKey>();
int num = 0;
int num2 = 0;
while (this.m_rightSource.MoveNext(ref pair, ref num))
{
if ((num2++ & 0x3f) == 0)
{
CancellationState.ThrowIfCanceled(this.m_cancellationToken);
}
TRightInput first = pair.First;
THashKey second = pair.Second;
if (second != null)
{
Pair <TRightInput, ListChunk <TRightInput> > pair2 = new Pair <TRightInput, ListChunk <TRightInput> >();
if (!mutables.m_rightHashLookup.TryGetValue(second, ref pair2))
{
pair2 = new Pair <TRightInput, ListChunk <TRightInput> >(first, null);
if (this.m_groupResultSelector != null)
{
pair2.Second = new ListChunk <TRightInput>(2);
pair2.Second.Add(first);
}
mutables.m_rightHashLookup.Add(second, pair2);
}
else
{
if (pair2.Second == null)
{
pair2.Second = new ListChunk <TRightInput>(2);
mutables.m_rightHashLookup[second] = pair2;
}
pair2.Second.Add(first);
}
}
}
}
ListChunk <TRightInput> currentRightMatches = mutables.m_currentRightMatches;
if ((currentRightMatches != null) && (mutables.m_currentRightMatchesIndex == currentRightMatches.Count))
{
currentRightMatches = mutables.m_currentRightMatches = currentRightMatches.Next;
mutables.m_currentRightMatchesIndex = 0;
}
if (mutables.m_currentRightMatches == null)
{
Pair <TLeftInput, THashKey> pair3 = new Pair <TLeftInput, THashKey>();
TLeftKey local3 = default(TLeftKey);
while (this.m_leftSource.MoveNext(ref pair3, ref local3))
{
if ((mutables.m_outputLoopCount++ & 0x3f) == 0)
{
CancellationState.ThrowIfCanceled(this.m_cancellationToken);
}
Pair <TRightInput, ListChunk <TRightInput> > pair4 = new Pair <TRightInput, ListChunk <TRightInput> >();
TLeftInput local4 = pair3.First;
THashKey key = pair3.Second;
if (((key != null) && mutables.m_rightHashLookup.TryGetValue(key, ref pair4)) && (this.m_singleResultSelector != null))
{
mutables.m_currentRightMatches = pair4.Second;
mutables.m_currentRightMatchesIndex = 0;
currentElement = this.m_singleResultSelector(local4, pair4.First);
currentKey = local3;
if (pair4.Second != null)
{
mutables.m_currentLeft = local4;
mutables.m_currentLeftKey = local3;
}
return(true);
}
if (this.m_groupResultSelector != null)
{
IEnumerable <TRightInput> enumerable = pair4.Second;
if (enumerable == null)
{
enumerable = (IEnumerable <TRightInput>)ParallelEnumerable.Empty <TRightInput>();
}
currentElement = this.m_groupResultSelector(local4, enumerable);
currentKey = local3;
return(true);
}
}
return(false);
}
currentElement = this.m_singleResultSelector(mutables.m_currentLeft, mutables.m_currentRightMatches.m_chunk[mutables.m_currentRightMatchesIndex]);
currentKey = mutables.m_currentLeftKey;
mutables.m_currentRightMatchesIndex++;
return(true);
}
//---------------------------------------------------------------------------------------
// Straightforward IEnumerator<T> methods.
//
internal override bool MoveNext(ref TOutput currentElement, ref Pair currentKey)
{
while (true)
{
if (_currentRightSource == null)
{
_mutables = new Mutables();
// Check cancellation every few lhs-enumerations in case none of them are producing
// any outputs. Otherwise, we rely on the consumer of this operator to be performing the checks.
if ((_mutables._lhsCount++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
// We don't have a "current" right enumerator to use. We have to fetch the next
// one. If the left has run out of elements, however, we're done and just return
// false right away.
if (!_leftSource.MoveNext(ref _mutables._currentLeftElement, ref _mutables._currentLeftKey))
{
return(false);
}
// Use the source selection routine to create a right child.
IEnumerable <TRightInput> rightChild = _selectManyOperator._rightChildSelector(_mutables._currentLeftElement);
Contract.Assert(rightChild != null);
_currentRightSource = rightChild.GetEnumerator();
Contract.Assert(_currentRightSource != null);
// If we have no result selector, we will need to access the Current element of the right
// data source as though it is a TOutput. Unfortunately, we know that TRightInput must
// equal TOutput (we check it during operator construction), but the type system doesn't.
// Thus we would have to cast the result of invoking Current from type TRightInput to
// TOutput. This is no good, since the results could be value types. Instead, we save the
// enumerator object as an IEnumerator<TOutput> and access that later on.
if (_selectManyOperator._resultSelector == null)
{
_currentRightSourceAsOutput = (IEnumerator <TOutput>)(object) _currentRightSource;
Contract.Assert(_currentRightSourceAsOutput == _currentRightSource,
"these must be equal, otherwise the surrounding logic will be broken");
}
}
if (_currentRightSource.MoveNext())
{
_mutables._currentRightSourceIndex++;
// If the inner data source has an element, we can yield it.
if (_selectManyOperator._resultSelector != null)
{
// In the case of a selection function, use that to yield the next element.
currentElement = _selectManyOperator._resultSelector(_mutables._currentLeftElement, _currentRightSource.Current);
}
else
{
// Otherwise, the right input and output types must be the same. We use the
// casted copy of the current right source and just return its current element.
Contract.Assert(_currentRightSourceAsOutput != null);
currentElement = _currentRightSourceAsOutput.Current;
}
currentKey = new Pair(_mutables._currentLeftKey, _mutables._currentRightSourceIndex);
return(true);
}
else
{
// Otherwise, we have exhausted the right data source. Loop back around and try
// to get the next left element, then its right, and so on.
_currentRightSource.Dispose();
_currentRightSource = null;
_currentRightSourceAsOutput = null;
}
}
}
//---------------------------------------------------------------------------------------
// Straightforward IEnumerator<T> methods.
//
internal override bool MoveNext([MaybeNullWhen(false), AllowNull] ref TSource currentElement, ref int currentKey)
{
Debug.Assert(_source != null);
if (_alreadySearched)
{
return(false);
}
// Look for the greatest element.
TSource candidate = default(TSource) !;
TKey candidateKey = default(TKey) !;
bool candidateFound = false;
try
{
int loopCount = 0; //counter to help with cancellation
TSource value = default(TSource) !;
TKey key = default(TKey) !;
while (_source.MoveNext(ref value !, ref key))
{
if ((loopCount & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
// If the predicate is null or the current element satisfies it, we will remember
// it as the current partition's candidate for the last element, and move on.
if (_predicate == null || _predicate(value))
{
candidate = value;
candidateKey = key;
candidateFound = true;
}
loopCount++;
}
// If we found a candidate element, try to publish it, so long as it's greater.
if (candidateFound)
{
lock (_operatorState)
{
if (_operatorState._partitionId == -1 || _keyComparer.Compare(candidateKey, _operatorState._key) > 0)
{
_operatorState._partitionId = _partitionId;
_operatorState._key = candidateKey;
}
}
}
}
finally
{
// No matter whether we exit due to an exception or normal completion, we must ensure
// that we signal other partitions that we have completed. Otherwise, we can cause deadlocks.
_sharedBarrier.Signal();
}
_alreadySearched = true;
// Only if we have a candidate do we wait.
if (_partitionId == _operatorState._partitionId)
{
_sharedBarrier.Wait(_cancellationToken);
// Now re-read the shared index. If it's the same as ours, we won and return true.
if (_operatorState._partitionId == _partitionId)
{
currentElement = candidate;
currentKey = 0; // 1st (and only) element, so we hardcode the output index to 0.
return(true);
}
}
// If we got here, we didn't win. Return false.
return(false);
}
//---------------------------------------------------------------------------------------
// Walks the two data sources, left and then right, to produce the union.
//
internal override bool MoveNext([MaybeNullWhen(false), AllowNull] ref TInputOutput currentElement, ref int currentKey)
{
if (_hashLookup == null)
{
_hashLookup = new Set <TInputOutput>(_comparer);
_outputLoopCount = new Shared <int>(0);
}
Debug.Assert(_hashLookup != null);
// Enumerate the left and then right data source. When each is done, we set the
// field to null so we will skip it upon subsequent calls to MoveNext.
if (_leftSource != null)
{
// Iterate over this set's elements until we find a unique element.
TLeftKey keyUnused = default(TLeftKey) !;
Pair <TInputOutput, NoKeyMemoizationRequired> currentLeftElement = default(Pair <TInputOutput, NoKeyMemoizationRequired>);
int i = 0;
while (_leftSource.MoveNext(ref currentLeftElement, ref keyUnused))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
// We ensure we never return duplicates by tracking them in our set.
if (_hashLookup.Add(currentLeftElement.First))
{
#if DEBUG
currentKey = unchecked ((int)0xdeadbeef);
#endif
currentElement = currentLeftElement.First;
return(true);
}
}
_leftSource.Dispose();
_leftSource = null;
}
if (_rightSource != null)
{
// Iterate over this set's elements until we find a unique element.
TRightKey keyUnused = default(TRightKey) !;
Pair <TInputOutput, NoKeyMemoizationRequired> currentRightElement = default(Pair <TInputOutput, NoKeyMemoizationRequired>);
while (_rightSource.MoveNext(ref currentRightElement, ref keyUnused))
{
Debug.Assert(_outputLoopCount != null);
if ((_outputLoopCount.Value++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
// We ensure we never return duplicates by tracking them in our set.
if (_hashLookup.Add(currentRightElement.First))
{
#if DEBUG
currentKey = unchecked ((int)0xdeadbeef);
#endif
currentElement = currentRightElement.First;
return(true);
}
}
_rightSource.Dispose();
_rightSource = null;
}
return(false);
}
internal override bool MoveNext(ref TResult currentElement, ref int currentKey)
{
if (this.m_buffer != null)
{
goto Label_0114;
}
List <Pair <TResult, int> > list = new List <Pair <TResult, int> >();
try
{
TResult local = default(TResult);
int num = 0;
int num2 = 0;
while (this.m_source.MoveNext(ref local, ref num))
{
bool flag;
if ((num2++ & 0x3f) == 0)
{
CancellationState.ThrowIfCanceled(this.m_cancellationToken);
}
list.Add(new Pair <TResult, int>(local, num));
int num3 = this.m_sharedLowFalse.Value;
if ((num3 != -1) && (num > num3))
{
goto Label_00F0;
}
if (this.m_predicate != null)
{
flag = this.m_predicate(local);
}
else
{
flag = this.m_indexedPredicate(local, num);
}
if (!flag)
{
SpinWait wait = new SpinWait();
while (true)
{
int comparand = Thread.VolatileRead(ref this.m_sharedLowFalse.Value);
if (((comparand != -1) && (comparand < num)) || (Interlocked.CompareExchange(ref this.m_sharedLowFalse.Value, num, comparand) == comparand))
{
goto Label_00F0;
}
wait.SpinOnce();
}
}
}
}
finally
{
this.m_sharedBarrier.Signal();
}
Label_00F0:
this.m_sharedBarrier.Wait(this.m_cancellationToken);
this.m_buffer = list;
this.m_bufferIndex = new Shared <int>(-1);
Label_0114:
if (this.m_take)
{
if (this.m_bufferIndex.Value >= (this.m_buffer.Count - 1))
{
return(false);
}
this.m_bufferIndex.Value += 1;
Pair <TResult, int> pair = this.m_buffer[this.m_bufferIndex.Value];
currentElement = pair.First;
Pair <TResult, int> pair2 = this.m_buffer[this.m_bufferIndex.Value];
currentKey = pair2.Second;
if (this.m_sharedLowFalse.Value != -1)
{
Pair <TResult, int> pair3 = this.m_buffer[this.m_bufferIndex.Value];
return(this.m_sharedLowFalse.Value > pair3.Second);
}
return(true);
}
if (this.m_sharedLowFalse.Value == -1)
{
return(false);
}
if (this.m_bufferIndex.Value < (this.m_buffer.Count - 1))
{
this.m_bufferIndex.Value += 1;
while (this.m_bufferIndex.Value < this.m_buffer.Count)
{
Pair <TResult, int> pair4 = this.m_buffer[this.m_bufferIndex.Value];
if (pair4.Second >= this.m_sharedLowFalse.Value)
{
Pair <TResult, int> pair5 = this.m_buffer[this.m_bufferIndex.Value];
currentElement = pair5.First;
Pair <TResult, int> pair6 = this.m_buffer[this.m_bufferIndex.Value];
currentKey = pair6.Second;
return(true);
}
this.m_bufferIndex.Value += 1;
}
}
return(this.m_source.MoveNext(ref currentElement, ref currentKey));
}
private readonly int _queryId; // Id of this query execution.
//-----------------------------------------------------------------------------------
// Creates a new shared bit of state among tasks.
//
internal QueryTaskGroupState(CancellationState cancellationState, int queryId)
{
_cancellationState = cancellationState;
_queryId = queryId;
}
protected override bool MoveNextCore(ref float?currentElement)
{
QueryOperatorEnumerator <float?, TKey> source = this.m_source;
TKey currentKey = default(TKey);
if (!source.MoveNext(ref currentElement, ref currentKey))
{
return(false);
}
int num = 0;
if (this.m_sign != -1)
{
float?nullable2 = null;
while (source.MoveNext(ref nullable2, ref currentKey))
{
if ((num++ & 0x3f) == 0)
{
CancellationState.ThrowIfCanceled(base.m_cancellationToken);
}
if (nullable2.HasValue)
{
if (currentElement.HasValue)
{
float?nullable5 = nullable2;
float?nullable6 = currentElement;
if (((nullable5.GetValueOrDefault() <= nullable6.GetValueOrDefault()) || !(nullable5.HasValue & nullable6.HasValue)) && !float.IsNaN(currentElement.GetValueOrDefault()))
{
continue;
}
}
currentElement = nullable2;
}
}
}
else
{
float?nullable = null;
while (source.MoveNext(ref nullable, ref currentKey))
{
if ((num++ & 0x3f) == 0)
{
CancellationState.ThrowIfCanceled(base.m_cancellationToken);
}
if (nullable.HasValue)
{
if (currentElement.HasValue)
{
float?nullable3 = nullable;
float?nullable4 = currentElement;
if (((nullable3.GetValueOrDefault() >= nullable4.GetValueOrDefault()) || !(nullable3.HasValue & nullable4.HasValue)) && !float.IsNaN(nullable.GetValueOrDefault()))
{
continue;
}
}
currentElement = nullable;
}
}
}
return(true);
}
/// <summary>
/// WrapEnumerable.ExceptionAggregator wraps the enumerable with another enumerator that will
/// catch exceptions, and wrap each with an AggregateException.
///
/// If PLINQ decides to execute a query sequentially, we will reuse LINQ-to-objects
/// implementations for the different operators. However, we still need to throw
/// AggregateException in the cases when parallel execution would have thrown an
/// AggregateException. Thus, we introduce a wrapper enumerator that catches exceptions
/// and wraps them with an AggregateException.
/// </summary>
internal static IEnumerable <TElement> WrapEnumerable <TElement>(IEnumerable <TElement> source, CancellationState cancellationState)
{
using (IEnumerator <TElement> enumerator = source.GetEnumerator())
{
while (true)
{
TElement elem = default(TElement);
try
{
if (!enumerator.MoveNext())
{
yield break;
}
elem = enumerator.Current;
}
catch (ThreadAbortException)
{
// Do not wrap ThreadAbortExceptions
throw;
}
catch (Exception ex)
{
ThrowOCEorAggregateException(ex, cancellationState);
}
yield return(elem);
}
}
}
//---------------------------------------------------------------------------------------
// This API, upon the first time calling it, walks the entire source query tree. It begins
// with an accumulator value set to the aggregation operator's seed, and always passes
// the accumulator along with the current element from the data source to the binary
// intermediary aggregation operator. The return value is kept in the accumulator. At
// the end, we will have our intermediate result, ready for final aggregation.
//
internal override bool MoveNext(ref TIntermediate currentElement, ref int currentKey)
{
Debug.Assert(_reduceOperator != null);
Debug.Assert(_reduceOperator._intermediateReduce != null, "expected a compiled operator");
// Only produce a single element. Return false if MoveNext() was already called before.
if (_accumulated)
{
return(false);
}
_accumulated = true;
bool hadNext = false;
TIntermediate accumulator = default(TIntermediate);
// Initialize the accumulator.
if (_reduceOperator._seedIsSpecified)
{
// If the seed is specified, initialize accumulator to the seed value.
accumulator = _reduceOperator._seedFactory == null
? _reduceOperator._seed
: _reduceOperator._seedFactory();
}
else
{
// If the seed is not specified, then we take the first element as the seed.
// Seed may be unspecified only if TInput is the same as TIntermediate.
Debug.Assert(typeof(TInput) == typeof(TIntermediate));
TInput acc = default(TInput);
TKey accKeyUnused = default(TKey);
if (!_source.MoveNext(ref acc, ref accKeyUnused))
{
return(false);
}
hadNext = true;
accumulator = (TIntermediate)((object)acc);
}
// Scan through the source and accumulate the result.
TInput input = default(TInput);
TKey keyUnused = default(TKey);
int i = 0;
while (_source.MoveNext(ref input, ref keyUnused))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
hadNext = true;
accumulator = _reduceOperator._intermediateReduce(accumulator, input);
}
if (hadNext)
{
currentElement = accumulator;
currentKey = _partitionIndex; // A reduction's "index" is just its partition number.
return(true);
}
return(false);
}
private int m_queryId; // Id of this query execution.
//-----------------------------------------------------------------------------------
// Creates a new shared bit of state among tasks.
//
internal QueryTaskGroupState(CancellationState cancellationState, int queryId)
{
m_cancellationState = cancellationState;
m_queryId = queryId;
}
//---------------------------------------------------------------------------------------
// Straightforward IEnumerator<T> methods.
//
internal override bool MoveNext(ref TSource currentElement, ref int currentKey)
{
Contract.Assert(m_source != null);
if (m_alreadySearched)
{
return(false);
}
// Look for the greatest element.
TSource candidate = default(TSource);
int candidateIndex = -1;
try
{
TSource current = default(TSource);
int key = default(int);
int loopCount = 0; //counter to help with cancellation
while (m_source.MoveNext(ref current, ref key))
{
if ((loopCount & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(m_cancellationToken);
}
// If the predicate is null or the current element satisfies it, we will remember
// it as the current partition's candidate for the last element, and move on.
if (m_predicate == null || m_predicate(current))
{
candidate = current;
candidateIndex = key;
}
loopCount++;
}
// If we found a candidate element, try to publish it, so long as it's greater.
if (candidateIndex != -1)
{
int observedSharedIndex;
do
{
observedSharedIndex = m_sharedLastCandidate.Value;
}while ((observedSharedIndex == -1 || candidateIndex > observedSharedIndex) &&
Interlocked.CompareExchange(ref m_sharedLastCandidate.Value, candidateIndex, observedSharedIndex) != observedSharedIndex);
}
}
finally
{
// No matter whether we exit due to an exception or normal completion, we must ensure
// that we signal other partitions that we have completed. Otherwise, we can cause deadlocks.
m_sharedBarrier.Signal();
}
m_alreadySearched = true;
// Only if we have a candidate do we wait.
if (candidateIndex != -1)
{
m_sharedBarrier.Wait(m_cancellationToken);
// Now re-read the shared index. If it's the same as ours, we won and return true.
if (m_sharedLastCandidate.Value == candidateIndex)
{
currentElement = candidate;
currentKey = 0; // 1st (and only) element, so we hardcode the output index to 0.
return(true);
}
}
// If we got here, we didn't win. Return false.
return(false);
}
