Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Common / internal / materialization / recordstate.cs / 1305376 / recordstate.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //[....] //----------------------------------------------------------------------------- using System.Collections.Generic; using System.Data.Metadata.Edm; using System.Linq; using System.Linq.Expressions; namespace System.Data.Common.Internal.Materialization { ////// The RecordState class is responsible for tracking state about a record /// that should be returned from a data reader. /// internal class RecordState { #region state ////// Where to find the static information about this record /// private readonly RecordStateFactory RecordStateFactory; ////// The coordinator factory (essentially, the reader) that we're a part of. /// internal readonly CoordinatorFactory CoordinatorFactory; ////// True when the record is supposed to be null. (Null Structured Types...) /// private bool _pendingIsNull; private bool _currentIsNull; ////// An EntityRecordInfo, with EntityKey and EntitySet populated; set /// by the GatherData expression. /// private EntityRecordInfo _currentEntityRecordInfo; private EntityRecordInfo _pendingEntityRecordInfo; ////// The column values; set by the GatherData expression. Really ought /// to be in the Shaper.State. /// internal object[] CurrentColumnValues; internal object[] PendingColumnValues; #endregion #region constructor internal RecordState(RecordStateFactory recordStateFactory, CoordinatorFactory coordinatorFactory) { this.RecordStateFactory = recordStateFactory; this.CoordinatorFactory = coordinatorFactory; this.CurrentColumnValues = new object[RecordStateFactory.ColumnCount]; this.PendingColumnValues = new object[RecordStateFactory.ColumnCount]; } #endregion #region "public" surface area ////// Move the PendingValues to the CurrentValues for this record and all nested /// records. We keep the pending values separate from the current ones because /// we may have a nested reader in the middle, and while we're reading forward /// on the nested reader we we'll blast over the pending values. /// /// This should be called as part of the data reader's Read() method. /// internal void AcceptPendingValues() { object[] temp = CurrentColumnValues; CurrentColumnValues = PendingColumnValues; PendingColumnValues = temp; _currentEntityRecordInfo = _pendingEntityRecordInfo; _pendingEntityRecordInfo = null; _currentIsNull = _pendingIsNull; // if (RecordStateFactory.HasNestedColumns) { for (int ordinal = 0; ordinal < CurrentColumnValues.Length; ordinal++) { if (RecordStateFactory.IsColumnNested[ordinal]) { RecordState recordState = CurrentColumnValues[ordinal] as RecordState; if (null != recordState) { recordState.AcceptPendingValues(); } } } } } ////// Return the number of columns /// internal int ColumnCount { get { return RecordStateFactory.ColumnCount; } } ////// Return the DataRecordInfo for this record; if we had an EntityRecordInfo /// set, then return it otherwise return the static one from the factory. /// internal DataRecordInfo DataRecordInfo { get { DataRecordInfo result = _currentEntityRecordInfo; if (null == result) { result = RecordStateFactory.DataRecordInfo; } return result; } } ////// Is the record NULL? /// internal bool IsNull { get { return _currentIsNull; } } ////// Implementation of DataReader's GetBytes method /// internal long GetBytes(int ordinal, long dataOffset, byte[] buffer, int bufferOffset, int length) { byte[] byteValue = (byte[])CurrentColumnValues[ordinal]; int valueLength = byteValue.Length; int sourceOffset = (int)dataOffset; int byteCount = valueLength - sourceOffset; if (null != buffer) { byteCount = Math.Min(byteCount, length); if (0 < byteCount) { Buffer.BlockCopy(byteValue, sourceOffset, buffer, bufferOffset, byteCount); } } return Math.Max(0, byteCount); } ////// Implementation of DataReader's GetChars method /// internal long GetChars(int ordinal, long dataOffset, char[] buffer, int bufferOffset, int length) { string stringValue = CurrentColumnValues[ordinal] as string; char[] charValue; if (stringValue != null) { charValue = stringValue.ToCharArray(); } else { charValue = (char[])CurrentColumnValues[ordinal]; } int valueLength = charValue.Length; int sourceOffset = (int)dataOffset; int charCount = valueLength - sourceOffset; if (null != buffer) { charCount = Math.Min(charCount, length); if (0 < charCount) { Buffer.BlockCopy(charValue, sourceOffset * System.Text.UnicodeEncoding.CharSize, buffer, bufferOffset * System.Text.UnicodeEncoding.CharSize, charCount * System.Text.UnicodeEncoding.CharSize); } } return Math.Max(0, charCount); } ////// Return the name of the column at the ordinal specified. /// internal string GetName(int ordinal) { // Some folks are picky about the exception we throw if (ordinal < 0 || ordinal >= RecordStateFactory.ColumnCount) { throw EntityUtil.ArgumentOutOfRange("ordinal"); } return RecordStateFactory.ColumnNames[ordinal]; } ////// This is where the GetOrdinal method for DbDataReader/DbDataRecord end up. /// internal int GetOrdinal(string name) { return RecordStateFactory.FieldNameLookup.GetOrdinal(name); } ////// Return the type of the column at the ordinal specified. /// internal TypeUsage GetTypeUsage(int ordinal) { return RecordStateFactory.TypeUsages[ordinal]; } ////// Returns true when the column at the ordinal specified is /// a record or reader column that requires special handling. /// internal bool IsNestedObject(int ordinal) { return RecordStateFactory.IsColumnNested[ordinal]; } ////// Called whenever we hand this record state out as the default state for /// a data reader; we will have already handled any existing data back to /// the previous group of records (that is, we couldn't be using it from two /// distinct readers at the same time). /// internal void ResetToDefaultState() { _currentEntityRecordInfo = null; } #endregion #region called from Shaper's Element Expression ////// Called from the Element expression on the Coordinator to gather all /// the data for the record; we just turn around and call the expression /// we build on the RecordStateFactory. /// internal RecordState GatherData(Shaper shaper) { RecordStateFactory.GatherData(shaper); _pendingIsNull = false; return this; } ////// Called by the GatherData expression to set the data for the /// specified column value /// internal bool SetColumnValue(int ordinal, object value) { PendingColumnValues[ordinal] = value; return true; } ////// Called by the GatherData expression to set the data for the /// EntityRecordInfo /// internal bool SetEntityRecordInfo(EntityKey entityKey, EntitySet entitySet) { _pendingEntityRecordInfo = new EntityRecordInfo(this.RecordStateFactory.DataRecordInfo, entityKey, entitySet); return true; } ////// Called from the Element expression on the Coordinator to indicate that /// the record should be NULL. /// internal RecordState SetNullRecord(Shaper shaper) { // for (int i = 0; i < PendingColumnValues.Length; i++) { PendingColumnValues[i] = DBNull.Value; } _pendingEntityRecordInfo = null; // the default is already setup correctly on the record state factory _pendingIsNull = true; return this; } #endregion } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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