Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Data / System / Data / SqlClient / SqlCachedBuffer.cs / 1 / SqlCachedBuffer.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //[....] //[....] //----------------------------------------------------------------------------- namespace System.Data.SqlClient { using System; using System.Collections; using System.ComponentModel; using System.Data; using System.Data.Common; using System.Diagnostics; using System.Globalization; using System.Text; using System.Xml; using System.Data.SqlTypes; using System.IO; using System.Runtime.InteropServices; using System.Reflection; // Caches the bytes returned from partial length prefixed datatypes, like XML sealed internal class SqlCachedBuffer : System.Data.SqlTypes.INullable{ ArrayList _cachedBytes; const int _maxChunkSize = 2048; // Arbitrary value for chunk size. Revisit this later for better perf // Reads off from the network buffer and caches bytes. Only reads one column value in the current row. internal SqlCachedBuffer(SqlMetaDataPriv metadata, TdsParser parser, TdsParserStateObject stateObj ) { int cb = 0; ulong plplength; byte[] byteArr; Debug.Assert(_cachedBytes == null, "Cache is already filled!"); _cachedBytes = new ArrayList(); // the very first length is already read. plplength = parser.PlpBytesLeft(stateObj);; // For now we only handle Plp data from the parser directly. Debug.Assert(metadata.metaType.IsPlp, "SqlCachedBuffer call on a non-plp data"); do { if (plplength == 0) break; do { cb = (plplength > (ulong) _maxChunkSize) ? _maxChunkSize : (int)plplength ; byteArr = new byte[cb]; cb = stateObj.ReadPlpBytes(ref byteArr, 0, cb); Debug.Assert(cb == byteArr.Length); if (_cachedBytes.Count == 0) { // Add the Byte order mark if needed if we read the first array AddByteOrderMark(byteArr); } _cachedBytes.Add(byteArr); plplength -= (ulong)cb; } while (plplength > 0); plplength = parser.PlpBytesLeft(stateObj); } while (plplength > 0); Debug.Assert(stateObj._longlen == 0 && stateObj._longlenleft == 0); } // Reads off from a reader and caches bytes. Only reads the first column of each row. internal SqlCachedBuffer(SqlDataReader dataRdr, bool cacheAllRows) { byte[] byteArr; long cb; long bytesRead; Debug.Assert(_cachedBytes == null, "Cache is already filled!"); _cachedBytes = new ArrayList(); do { if (dataRdr.Read()) { do { bytesRead = 0; cb = dataRdr.GetBytesInternal(0, 0, null, 0, 0); //InternalGetBytes(int i, long dataIndex, byte[] buffer, int bufferIndex, int length) // Get no. of bytes while (cb != 0) { int cbread = (cb > (long)_maxChunkSize || (cb < 0) ) ? _maxChunkSize : (int) cb; byteArr = new byte[cbread]; cbread = (int) dataRdr.GetBytesInternal(0, bytesRead, byteArr, 0, cbread); // If we got less bytes than we requested, we hit the end if((cbread > 0) && (cbread < byteArr.Length)) { byte[] newByteArr = new byte[cbread]; Buffer.BlockCopy(byteArr, 0, newByteArr, 0, cbread); byteArr = newByteArr; } if (_cachedBytes.Count == 0) { // Add the Byte order mark if needed if we read the first array AddByteOrderMark(byteArr); } if (cbread == 0) break; _cachedBytes.Add(byteArr); cb -= (long)cbread; bytesRead += cbread; if (cb == 0) { cb = dataRdr.GetBytesInternal(0, 0, null, 0, 0); } } }while(cacheAllRows && dataRdr.Read()); } } while (cacheAllRows && dataRdr.NextResult()); } private void AddByteOrderMark(byte[] byteArr ) { int bom = 0xfeff; // Need to find out if we should add byte order mark or not. // We need to add this if we are getting ntext xml, not if we are getting binary xml // Binary Xml always begins with the bytes 0xDF and 0xFF // If we aren't getting these, then we are getting unicode xml if ((byteArr.Length >= 2 ) && (byteArr[0] == 0xDF) && (byteArr[1] == 0xFF)){ bom = 0; } if (bom != 0) { byte[] b = new byte[2]; b[0] = (byte)bom; bom >>= 8; b[1] = (byte)bom; Debug.Assert(_cachedBytes.Count == 0); _cachedBytes.Add(b); } return; } private SqlCachedBuffer() { // For constructing Null } public static readonly SqlCachedBuffer Null = new SqlCachedBuffer(); internal ArrayList CachedBytes { get { return _cachedBytes; } } override public string ToString() { if (IsNull) throw new SqlNullValueException(); if (_cachedBytes.Count == 0) { return String.Empty; } SqlCachedStream fragment = new SqlCachedStream(this); SqlXml sxml = new SqlXml((Stream)fragment); return sxml.Value; } internal SqlString ToSqlString() { if (IsNull) return SqlString.Null; string str = ToString(); return new SqlString(str); } internal SqlXml ToSqlXml() { SqlCachedStream fragment = new SqlCachedStream(this); SqlXml sx = new SqlXml((Stream)fragment); return sx; } internal XmlReader ToXmlReader() { SqlCachedStream fragment = new SqlCachedStream(this); //XmlTextReader xr = new XmlTextReader(fragment, XmlNodeType.Element, null); XmlReaderSettings readerSettings = new XmlReaderSettings(); readerSettings.ConformanceLevel = ConformanceLevel.Fragment; // Call internal XmlReader.CreateSqlReader from System.Xml. // Signature: internal static XmlReader CreateSqlReader(Stream input, XmlReaderSettings settings, XmlParserContext inputContext); MethodInfo createSqlReaderMethodInfo = typeof(System.Xml.XmlReader).GetMethod("CreateSqlReader", BindingFlags.Static | BindingFlags.NonPublic); object[] args = new object[3] { (Stream)fragment, readerSettings, null }; XmlReader xr; new System.Security.Permissions.ReflectionPermission(System.Security.Permissions.ReflectionPermissionFlag.MemberAccess).Assert(); try { xr = (XmlReader)createSqlReaderMethodInfo.Invoke(null, args); } finally { System.Security.Permissions.ReflectionPermission.RevertAssert(); } return xr; } public bool IsNull { get { return (_cachedBytes == null) ? true : false ; } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- AttachInfo.cs
- XmlObjectSerializerContext.cs
- SimpleHandlerBuildProvider.cs
- PrintControllerWithStatusDialog.cs
- OleDbConnectionPoolGroupProviderInfo.cs
- XmlArrayItemAttributes.cs
- SearchForVirtualItemEventArgs.cs
- WebPartZoneBase.cs
- SystemThemeKey.cs
- XmlSchemaSimpleTypeUnion.cs
- x509utils.cs
- FormViewDeleteEventArgs.cs
- HealthMonitoringSectionHelper.cs
- SemanticTag.cs
- SystemInfo.cs
- TemplateXamlTreeBuilder.cs
- ECDsa.cs
- FontEmbeddingManager.cs
- MenuAdapter.cs
- GridViewColumnCollection.cs
- SqlUtil.cs
- BinaryObjectWriter.cs
- InputMethodStateTypeInfo.cs
- AddInActivator.cs
- AdornerLayer.cs
- BorderGapMaskConverter.cs
- AdRotator.cs
- BooleanStorage.cs
- PointKeyFrameCollection.cs
- RuntimeHandles.cs
- SqlDataRecord.cs
- Single.cs
- ServicePointManagerElement.cs
- SqlNotificationEventArgs.cs
- PathBox.cs
- ConversionContext.cs
- ApplyImportsAction.cs
- SmtpDigestAuthenticationModule.cs
- AccessText.cs
- TemplatedMailWebEventProvider.cs
- SmtpClient.cs
- ProtectedConfigurationProviderCollection.cs
- WebPartConnectionsCancelVerb.cs
- SQLMoneyStorage.cs
- ListChangedEventArgs.cs
- ObjectStateEntryDbDataRecord.cs
- ResourceAttributes.cs
- SqlGenerator.cs
- COM2DataTypeToManagedDataTypeConverter.cs
- FormsAuthenticationConfiguration.cs
- Color.cs
- ResourceReferenceExpression.cs
- safesecurityhelperavalon.cs
- Queue.cs
- QueryModel.cs
- Random.cs
- DbFunctionCommandTree.cs
- SubpageParaClient.cs
- SymbolMethod.cs
- Quaternion.cs
- ConnectionPoint.cs
- NamedPipeTransportSecurityElement.cs
- __Filters.cs
- CookieParameter.cs
- AliasGenerator.cs
- ExtensibleClassFactory.cs
- CompoundFileDeflateTransform.cs
- StorageAssociationSetMapping.cs
- ClassHandlersStore.cs
- SectionInput.cs
- CryptographicAttribute.cs
- AnnotationAuthorChangedEventArgs.cs
- httpstaticobjectscollection.cs
- JavaScriptString.cs
- FamilyCollection.cs
- FrameworkRichTextComposition.cs
- diagnosticsswitches.cs
- CaseInsensitiveOrdinalStringComparer.cs
- Figure.cs
- WindowsClaimSet.cs
- ValidateNames.cs
- ClassDataContract.cs
- AutomationIdentifierGuids.cs
- ConfigurationSection.cs
- StandardCommands.cs
- KeyNameIdentifierClause.cs
- AutomationProperties.cs
- ExpressionList.cs
- TextInfo.cs
- RequestValidator.cs
- BoolExpr.cs
- ThreadInterruptedException.cs
- OdbcConnectionString.cs
- RecipientIdentity.cs
- ScanQueryOperator.cs
- PkcsMisc.cs
- QueryableFilterUserControl.cs
- Point3DCollection.cs
- VScrollBar.cs
- BaseProcessor.cs