Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Core / System / Linq / Parallel / QueryOperators / Unary / SelectQueryOperator.cs / 1305376 / SelectQueryOperator.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ // // SelectQueryOperator.cs // //[....] // // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- using System.Collections.Generic; using System.Diagnostics.Contracts; using System.Threading; namespace System.Linq.Parallel { ////// The operator type for Select statements. This operator transforms elements as it /// enumerates them through the use of a selector delegate. /// ////// internal sealed class SelectQueryOperator : UnaryQueryOperator { // Selector function. Used to project elements to a transformed view during execution. private Func m_selector; //---------------------------------------------------------------------------------------- // Initializes a new select operator. // // Arguments: // child - the child operator or data source from which to pull data // selector - a delegate representing the selector function // // Assumptions: // selector must be non null. // internal SelectQueryOperator(IEnumerable child, Func selector) :base(child) { Contract.Assert(child != null, "child data source cannot be null"); Contract.Assert(selector != null, "need a selector function"); m_selector = selector; SetOrdinalIndexState(Child.OrdinalIndexState); } internal override void WrapPartitionedStream ( PartitionedStream inputStream, IPartitionedStreamRecipient recipient, bool preferStriping, QuerySettings settings) { PartitionedStream outputStream = new PartitionedStream (inputStream.PartitionCount, inputStream.KeyComparer, OrdinalIndexState); for (int i = 0; i < inputStream.PartitionCount; i++) { outputStream[i] = new SelectQueryOperatorEnumerator (inputStream[i], m_selector); } recipient.Receive(outputStream); } //--------------------------------------------------------------------------------------- // Just opens the current operator, including opening the child and wrapping it with // partitions as needed. // internal override QueryResults Open(QuerySettings settings, bool preferStriping) { QueryResults childQueryResults = Child.Open(settings, preferStriping); return SelectQueryOperatorResults.NewResults(childQueryResults, this, settings, preferStriping); } internal override IEnumerable AsSequentialQuery(CancellationToken token) { return Child.AsSequentialQuery(token).Select(m_selector); } //--------------------------------------------------------------------------------------- // Whether this operator performs a premature merge. // internal override bool LimitsParallelism { get { return false; } } //--------------------------------------------------------------------------------------- // The enumerator type responsible for projecting elements as it is walked. // class SelectQueryOperatorEnumerator : QueryOperatorEnumerator { private readonly QueryOperatorEnumerator m_source; // The data source to enumerate. private readonly Func m_selector; // The actual select function. //---------------------------------------------------------------------------------------- // Instantiates a new select enumerator. // internal SelectQueryOperatorEnumerator(QueryOperatorEnumerator source, Func selector) { Contract.Assert(source != null); Contract.Assert(selector != null); m_source = source; m_selector = selector; } //--------------------------------------------------------------------------------------- // Straightforward IEnumerator methods. // internal override bool MoveNext(ref TOutput currentElement, ref TKey currentKey) { // So long as the source has a next element, we have an element. TInput element = default(TInput); if (m_source.MoveNext(ref element, ref currentKey)) { Contract.Assert(m_selector != null, "expected a compiled operator"); currentElement = m_selector(element); return true; } return false; } protected override void Dispose(bool disposing) { m_source.Dispose(); } } //------------------------------------------------------------------------------------ // Query results for a Select operator. The results are indexible if the child // results were indexible. // class SelectQueryOperatorResults : UnaryQueryOperatorResults { private Func m_selector; // Selector function private int m_childCount; // The number of elements in child results public static QueryResults NewResults( QueryResults childQueryResults, SelectQueryOperator op, QuerySettings settings, bool preferStriping) { if (childQueryResults.IsIndexible) { return new SelectQueryOperatorResults(childQueryResults, op, settings, preferStriping); } else { return new UnaryQueryOperatorResults(childQueryResults, op, settings, preferStriping); } } private SelectQueryOperatorResults( QueryResults childQueryResults, SelectQueryOperator op, QuerySettings settings, bool preferStriping) : base(childQueryResults, op, settings, preferStriping) { Contract.Assert(op.m_selector != null); m_selector = op.m_selector; Contract.Assert(m_childQueryResults.IsIndexible); m_childCount = m_childQueryResults.ElementsCount; } internal override bool IsIndexible { get { return true; } } internal override int ElementsCount { get { return m_childCount; } } internal override TOutput GetElement(int index) { Contract.Assert(index >= 0); Contract.Assert(index < ElementsCount); return m_selector(m_childQueryResults.GetElement(index)); } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ // // SelectQueryOperator.cs // // [....] // // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- using System.Collections.Generic; using System.Diagnostics.Contracts; using System.Threading; namespace System.Linq.Parallel { ////// The operator type for Select statements. This operator transforms elements as it /// enumerates them through the use of a selector delegate. /// ////// internal sealed class SelectQueryOperator : UnaryQueryOperator { // Selector function. Used to project elements to a transformed view during execution. private Func m_selector; //---------------------------------------------------------------------------------------- // Initializes a new select operator. // // Arguments: // child - the child operator or data source from which to pull data // selector - a delegate representing the selector function // // Assumptions: // selector must be non null. // internal SelectQueryOperator(IEnumerable child, Func selector) :base(child) { Contract.Assert(child != null, "child data source cannot be null"); Contract.Assert(selector != null, "need a selector function"); m_selector = selector; SetOrdinalIndexState(Child.OrdinalIndexState); } internal override void WrapPartitionedStream ( PartitionedStream inputStream, IPartitionedStreamRecipient recipient, bool preferStriping, QuerySettings settings) { PartitionedStream outputStream = new PartitionedStream (inputStream.PartitionCount, inputStream.KeyComparer, OrdinalIndexState); for (int i = 0; i < inputStream.PartitionCount; i++) { outputStream[i] = new SelectQueryOperatorEnumerator (inputStream[i], m_selector); } recipient.Receive(outputStream); } //--------------------------------------------------------------------------------------- // Just opens the current operator, including opening the child and wrapping it with // partitions as needed. // internal override QueryResults Open(QuerySettings settings, bool preferStriping) { QueryResults childQueryResults = Child.Open(settings, preferStriping); return SelectQueryOperatorResults.NewResults(childQueryResults, this, settings, preferStriping); } internal override IEnumerable AsSequentialQuery(CancellationToken token) { return Child.AsSequentialQuery(token).Select(m_selector); } //--------------------------------------------------------------------------------------- // Whether this operator performs a premature merge. // internal override bool LimitsParallelism { get { return false; } } //--------------------------------------------------------------------------------------- // The enumerator type responsible for projecting elements as it is walked. // class SelectQueryOperatorEnumerator : QueryOperatorEnumerator { private readonly QueryOperatorEnumerator m_source; // The data source to enumerate. private readonly Func m_selector; // The actual select function. //---------------------------------------------------------------------------------------- // Instantiates a new select enumerator. // internal SelectQueryOperatorEnumerator(QueryOperatorEnumerator source, Func selector) { Contract.Assert(source != null); Contract.Assert(selector != null); m_source = source; m_selector = selector; } //--------------------------------------------------------------------------------------- // Straightforward IEnumerator methods. // internal override bool MoveNext(ref TOutput currentElement, ref TKey currentKey) { // So long as the source has a next element, we have an element. TInput element = default(TInput); if (m_source.MoveNext(ref element, ref currentKey)) { Contract.Assert(m_selector != null, "expected a compiled operator"); currentElement = m_selector(element); return true; } return false; } protected override void Dispose(bool disposing) { m_source.Dispose(); } } //------------------------------------------------------------------------------------ // Query results for a Select operator. The results are indexible if the child // results were indexible. // class SelectQueryOperatorResults : UnaryQueryOperatorResults { private Func m_selector; // Selector function private int m_childCount; // The number of elements in child results public static QueryResults NewResults( QueryResults childQueryResults, SelectQueryOperator op, QuerySettings settings, bool preferStriping) { if (childQueryResults.IsIndexible) { return new SelectQueryOperatorResults(childQueryResults, op, settings, preferStriping); } else { return new UnaryQueryOperatorResults(childQueryResults, op, settings, preferStriping); } } private SelectQueryOperatorResults( QueryResults childQueryResults, SelectQueryOperator op, QuerySettings settings, bool preferStriping) : base(childQueryResults, op, settings, preferStriping) { Contract.Assert(op.m_selector != null); m_selector = op.m_selector; Contract.Assert(m_childQueryResults.IsIndexible); m_childCount = m_childQueryResults.ElementsCount; } internal override bool IsIndexible { get { return true; } } internal override int ElementsCount { get { return m_childCount; } } internal override TOutput GetElement(int index) { Contract.Assert(index >= 0); Contract.Assert(index < ElementsCount); return m_selector(m_childQueryResults.GetElement(index)); } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- TagPrefixAttribute.cs
- DataFieldCollectionEditor.cs
- PenThread.cs
- DropDownButton.cs
- Attributes.cs
- StoragePropertyMapping.cs
- NetworkCredential.cs
- DataGridBoolColumn.cs
- StringFunctions.cs
- XmlParserContext.cs
- CombinedGeometry.cs
- RemotingSurrogateSelector.cs
- NodeInfo.cs
- EncodingDataItem.cs
- SoapExtensionReflector.cs
- VisualCollection.cs
- MimeTypeMapper.cs
- _SslState.cs
- ReferentialConstraint.cs
- InternalControlCollection.cs
- TemplateBamlRecordReader.cs
- _ListenerResponseStream.cs
- OciLobLocator.cs
- DbExpressionVisitor.cs
- SessionConnectionReader.cs
- COM2ColorConverter.cs
- InternalPermissions.cs
- DocumentViewer.cs
- CfgParser.cs
- UshortList2.cs
- validationstate.cs
- TextDecorationCollection.cs
- MiniLockedBorderGlyph.cs
- SortFieldComparer.cs
- FormsAuthentication.cs
- ResourceDefaultValueAttribute.cs
- DataGridViewTextBoxEditingControl.cs
- Socket.cs
- DelegateArgument.cs
- ComplexObject.cs
- __Error.cs
- NamespaceList.cs
- MainMenu.cs
- DispatcherEventArgs.cs
- WebSysDescriptionAttribute.cs
- Style.cs
- SafeNativeMethods.cs
- cache.cs
- ListDictionary.cs
- SequenceDesigner.cs
- FaultContractInfo.cs
- OptimizedTemplateContentHelper.cs
- DataRowView.cs
- SimpleMailWebEventProvider.cs
- MemberAssignment.cs
- ReversePositionQuery.cs
- PersonalizationState.cs
- NullableDecimalAverageAggregationOperator.cs
- OleDbTransaction.cs
- Label.cs
- TypeElementCollection.cs
- SelectionList.cs
- CoreSwitches.cs
- DataServicePagingProviderWrapper.cs
- ClientConfigPaths.cs
- XmlSerializationWriter.cs
- TagPrefixCollection.cs
- EdmRelationshipRoleAttribute.cs
- XmlAttributeCollection.cs
- UserControl.cs
- KeyedCollection.cs
- PeerCollaborationPermission.cs
- DriveInfo.cs
- ReadOnlyDataSourceView.cs
- KnownIds.cs
- QuaternionRotation3D.cs
- MasterPageCodeDomTreeGenerator.cs
- TimersDescriptionAttribute.cs
- ScriptRegistrationManager.cs
- Currency.cs
- _LocalDataStore.cs
- InkPresenter.cs
- DbExpressionRules.cs
- BaseTemplateBuildProvider.cs
- Expr.cs
- CultureInfo.cs
- SqlDataRecord.cs
- CoreSwitches.cs
- SqlDeflator.cs
- ViewBase.cs
- AccessDataSource.cs
- AlphabeticalEnumConverter.cs
- InvokeMethod.cs
- Oid.cs
- CustomGrammar.cs
- _LocalDataStoreMgr.cs
- RetrieveVirtualItemEventArgs.cs
- SoapSchemaExporter.cs
- DbExpressionVisitor_TResultType.cs
- ControlBuilder.cs