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//------------------------------------------------------------------------------
// <copyright file="SqlStream.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
// <owner current="true" primary="true">Microsoft</owner>
// <owner current="true" primary="false">Microsoft</owner>
//------------------------------------------------------------------------------
namespace System.Data.SqlClient {
using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.Common;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;
using System.Xml;
using System.Reflection;
using System.Runtime.CompilerServices;
sealed internal class SqlStream : Stream {
private SqlDataReader _reader; // reader we will stream off
private int _columnOrdinal;
private long _bytesCol;
int _bom;
private byte[] _bufferedData;
private bool _processAllRows;
private bool _advanceReader;
private bool _readFirstRow = false;
private bool _endOfColumn = false;
internal SqlStream(SqlDataReader reader, bool addByteOrderMark, bool processAllRows) :
this(0, reader, addByteOrderMark, processAllRows, true) {
}
internal SqlStream(int columnOrdinal, SqlDataReader reader, bool addByteOrderMark , bool processAllRows, bool advanceReader) {
_columnOrdinal = columnOrdinal;
_reader = reader;
_bom = addByteOrderMark ? 0xfeff : 0;
_processAllRows = processAllRows;
_advanceReader = advanceReader;
}
override public bool CanRead {
get {
return true;
}
}
override public bool CanSeek {
get {
return false;
}
}
override public bool CanWrite {
get {
return false;
}
}
override public long Length {
get {
throw ADP.NotSupported();
}
}
override public long Position {
get {
throw ADP.NotSupported();
}
set {
throw ADP.NotSupported();
}
}
override protected void Dispose(bool disposing) {
try {
if (disposing && _advanceReader && _reader != null && !_reader.IsClosed) {
_reader.Close();
}
_reader = null;
}
finally {
base.Dispose(disposing);
}
}
override public void Flush() {
throw ADP.NotSupported();
}
override public int Read(byte[] buffer, int offset, int count) {
int intCount = 0;
int cBufferedData = 0;
if ((null == _reader)) {
throw ADP.StreamClosed(ADP.Read);
}
if (null == buffer) {
throw ADP.ArgumentNull(ADP.ParameterBuffer);
}
if ((offset < 0) || (count < 0)) {
throw ADP.ArgumentOutOfRange(String.Empty, (offset < 0 ? ADP.ParameterOffset : ADP.ParameterCount));
}
if (buffer.Length - offset < count) {
throw ADP.ArgumentOutOfRange(ADP.ParameterCount);
}
// 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 (_bom > 0 ) {
// Read and buffer the first two bytes
_bufferedData = new byte[2];
cBufferedData = ReadBytes(_bufferedData, 0, 2);
// Check to se if we should add the byte order mark
if ((cBufferedData < 2) || ((_bufferedData[0] == 0xDF) && (_bufferedData[1] == 0xFF))){
_bom = 0;
}
while (count > 0) {
if (_bom > 0) {
buffer[offset] = (byte)_bom;
_bom >>= 8;
offset++;
count--;
intCount++;
}
else {
break;
}
}
}
if (cBufferedData > 0) {
while (count > 0) {
buffer[offset++] = _bufferedData[0];
intCount++;
count--;
if ((cBufferedData > 1) && (count > 0)) {
buffer[offset++] = _bufferedData[1];
intCount++;
count--;
break;
}
}
_bufferedData = null;
}
intCount += ReadBytes(buffer, offset, count);
return intCount;
}
private static bool AdvanceToNextRow(SqlDataReader reader) {
Debug.Assert(reader != null && !reader.IsClosed);
// this method skips empty result sets
do {
if (reader.Read()) {
return true;
}
} while (reader.NextResult());
// no more rows
return false;
}
private int ReadBytes(byte[] buffer, int offset, int count) {
bool gotData = true;
int intCount = 0;
int cb = 0;
if (_reader.IsClosed || _endOfColumn) {
return 0;
}
try {
while (count > 0) {
// if I haven't read any bytes, get the next row
if (_advanceReader && (0 == _bytesCol)) {
gotData = false;
if (_readFirstRow && !_processAllRows) {
// for XML column, stop processing after the first row
// no op here - reader is closed after the end of this loop
}
else if (AdvanceToNextRow(_reader)) {
_readFirstRow = true;
if (_reader.IsDBNull(_columnOrdinal)) {
// VSTFDEVDIV 479659: handle row with DBNULL as empty data
// for XML column, processing is stopped on the next loop since _readFirstRow is true
continue;
}
// the value is not null, read it
gotData = true;
}
// else AdvanceToNextRow has returned false - no more rows or result sets remained, stop processing
}
if (gotData) {
cb = (int) _reader.GetBytesInternal(_columnOrdinal, _bytesCol, buffer, offset, count);
if (cb < count) {
_bytesCol = 0;
gotData = false;
if (!_advanceReader) {
_endOfColumn = true;
}
}
else {
Debug.Assert(cb == count);
_bytesCol += cb;
}
// we are guaranteed that cb is < Int32.Max since we always pass in count which is of type Int32 to
// our getbytes interface
count -= (int)cb;
offset += (int)cb;
intCount += (int)cb;
}
else {
break; // no more data available, we are done
}
}
if (!gotData && _advanceReader) {
_reader.Close(); // Need to close the reader if we are done reading
}
}
catch (Exception e) {
if (_advanceReader && ADP.IsCatchableExceptionType(e)) {
_reader.Close();
}
throw;
}
return intCount;
}
internal XmlReader ToXmlReader() {
// Dev11 Bug #315513: Exception type breaking change from 4.0 RTM when calling GetChars on null xml
// We need to wrap all exceptions inside a TargetInvocationException to simulate calling CreateSqlReader via MethodInfo.Invoke
return SqlTypes.SqlXml.CreateSqlXmlReader(this, closeInput: true, throwTargetInvocationExceptions: true);
}
override public long Seek(long offset, SeekOrigin origin) {
throw ADP.NotSupported();
}
override public void SetLength(long value) {
throw ADP.NotSupported();
}
override public void Write(byte[] buffer, int offset, int count) {
throw ADP.NotSupported();
}
}
// XmlTextReader does not read all the bytes off the network buffers, so we have to cache it here in the random access
// case. This causes double buffering and is a perf hit, but this is not the high perf way for accessing this type of data.
// In the case of sequential access, we do not have to do any buffering since the XmlTextReader we return can become
// invalid as soon as we move off the current column.
sealed internal class SqlCachedStream : Stream {
int _currentPosition; // Position within the current array byte
int _currentArrayIndex; // Index into the _cachedBytes ArrayList
List<byte[]> _cachedBytes;
long _totalLength;
// Reads off from the network buffer and caches bytes. Only reads one column value in the current row.
internal SqlCachedStream(SqlCachedBuffer sqlBuf ) {
_cachedBytes = sqlBuf.CachedBytes;
}
override public bool CanRead {
get {
return true;
}
}
override public bool CanSeek {
get {
return true;
}
}
override public bool CanWrite {
get {
return false;
}
}
override public long Length {
get {
return TotalLength;
}
}
override public long Position {
get {
long pos = 0;
if (_currentArrayIndex > 0) {
for (int ii = 0 ; ii < _currentArrayIndex ; ii++) {
pos += _cachedBytes[ii].Length;
}
}
pos += _currentPosition;
return pos;
}
set {
if (null == _cachedBytes) {
throw ADP.StreamClosed(ADP.ParameterSetPosition);
}
SetInternalPosition(value, ADP.ParameterSetPosition);
}
}
override protected void Dispose(bool disposing) {
try {
if (disposing && _cachedBytes != null)
_cachedBytes.Clear();
_cachedBytes = null;
_currentPosition = 0;
_currentArrayIndex = 0;
_totalLength = 0;
}
finally {
base.Dispose(disposing);
}
}
override public void Flush() {
throw ADP.NotSupported();
}
override public int Read(byte[] buffer, int offset, int count) {
int cb;
int intCount = 0;
if (null == _cachedBytes) {
throw ADP.StreamClosed(ADP.Read);
}
if (null == buffer) {
throw ADP.ArgumentNull(ADP.ParameterBuffer);
}
if ((offset < 0) || (count < 0)) {
throw ADP.ArgumentOutOfRange(String.Empty, (offset < 0 ? ADP.ParameterOffset : ADP.ParameterCount));
}
if (buffer.Length - offset < count) {
throw ADP.ArgumentOutOfRange(ADP.ParameterCount);
}
if (_cachedBytes.Count <= _currentArrayIndex) {
return 0; // Everything is read!
}
while (count > 0) {
if (_cachedBytes[_currentArrayIndex].Length <= _currentPosition) {
_currentArrayIndex++; // We are done reading this chunk, go to next
if (_cachedBytes.Count > _currentArrayIndex) {
_currentPosition = 0;
}
else {
break;
}
}
cb = _cachedBytes[_currentArrayIndex].Length - _currentPosition;
if (cb > count)
cb = count;
Array.Copy(_cachedBytes[_currentArrayIndex], _currentPosition, buffer, offset, cb);
_currentPosition += cb;
count -= (int)cb;
offset += (int)cb;
intCount += (int)cb;
}
return intCount;
}
override public long Seek(long offset, SeekOrigin origin) {
long pos = 0;
if (null == _cachedBytes) {
throw ADP.StreamClosed(ADP.Read);
}
switch(origin) {
case SeekOrigin.Begin:
SetInternalPosition(offset, ADP.ParameterOffset);
break;
case SeekOrigin.Current:
pos = offset + Position;
SetInternalPosition(pos, ADP.ParameterOffset);
break;
case SeekOrigin.End:
pos = TotalLength + offset;
SetInternalPosition(pos, ADP.ParameterOffset);
break;
default:
throw ADP.InvalidSeekOrigin(ADP.ParameterOffset);
}
return pos;
}
override public void SetLength(long value) {
throw ADP.NotSupported();
}
override public void Write(byte[] buffer, int offset, int count) {
throw ADP.NotSupported();
}
private void SetInternalPosition(long lPos, string argumentName) {
long pos = lPos;
if (pos < 0) {
throw new ArgumentOutOfRangeException(argumentName);
}
for (int ii = 0 ; ii < _cachedBytes.Count ; ii++) {
if (pos > _cachedBytes[ii].Length) {
pos -= _cachedBytes[ii].Length;
}
else {
_currentArrayIndex = ii;
_currentPosition = (int)pos;
return;
}
}
if (pos > 0)
throw new ArgumentOutOfRangeException(argumentName);
}
private long TotalLength {
get {
if ((_totalLength == 0) && (_cachedBytes != null)) {
long pos = 0;
for (int ii = 0 ; ii < _cachedBytes.Count ; ii++) {
pos += _cachedBytes[ii].Length;
}
_totalLength = pos;
}
return _totalLength;
}
}
}
sealed internal class SqlStreamingXml {
int _columnOrdinal;
SqlDataReader _reader;
XmlReader _xmlReader;
XmlWriter _xmlWriter;
StringWriter _strWriter;
long _charsRemoved;
public SqlStreamingXml(int i, SqlDataReader reader) {
_columnOrdinal = i;
_reader = reader;
}
public void Close() {
((IDisposable)_xmlWriter).Dispose();
((IDisposable)_xmlReader).Dispose();
_reader = null;
_xmlReader = null;
_xmlWriter = null;
_strWriter = null;
}
public int ColumnOrdinal {
get {
return _columnOrdinal;
}
}
public long GetChars(long dataIndex, char[] buffer, int bufferIndex, int length) {
if (_xmlReader == null) {
SqlStream sqlStream = new SqlStream( _columnOrdinal, _reader, true /* addByteOrderMark */, false /* processAllRows*/, false /*advanceReader*/);
_xmlReader = sqlStream.ToXmlReader();
_strWriter = new StringWriter((System.IFormatProvider)null);
XmlWriterSettings writerSettings = new XmlWriterSettings();
writerSettings.CloseOutput = true; // close the memory stream when done
writerSettings.ConformanceLevel = ConformanceLevel.Fragment;
_xmlWriter = XmlWriter.Create(_strWriter, writerSettings);
}
int charsToSkip = 0;
int cnt = 0;
if (dataIndex < _charsRemoved) {
throw ADP.NonSeqByteAccess(dataIndex, _charsRemoved, ADP.GetChars);
}
else if (dataIndex > _charsRemoved) {
charsToSkip = (int)(dataIndex - _charsRemoved);
}
// If buffer parameter is null, we have to return -1 since there is no way for us to know the
// total size up front without reading and converting the XML.
if (buffer == null) {
return (long)(-1);
}
StringBuilder strBldr = _strWriter.GetStringBuilder();
while (!_xmlReader.EOF) {
if (strBldr.Length >= (length+ charsToSkip)) {
break;
}
// Can't call _xmlWriter.WriteNode here, since it reads all of the data in before returning the first char.
// Do own implementation of WriteNode instead that reads just enough data to return the required number of chars
//_xmlWriter.WriteNode(_xmlReader, true);
// _xmlWriter.Flush();
WriteXmlElement();
if (charsToSkip > 0) {
// Aggressively remove the characters we want to skip to avoid growing StringBuilder size too much
cnt = strBldr.Length < charsToSkip ? strBldr.Length : charsToSkip;
strBldr.Remove(0, cnt);
charsToSkip -= cnt;
_charsRemoved +=(long)cnt;
}
}
if (charsToSkip > 0) {
cnt = strBldr.Length < charsToSkip ? strBldr.Length : charsToSkip;
strBldr.Remove(0, cnt);
charsToSkip -= cnt;
_charsRemoved +=(long)cnt;
}
if (strBldr.Length == 0) {
return 0;
}
// At this point charsToSkip must be 0
Debug.Assert(charsToSkip == 0);
cnt = strBldr.Length < length ? strBldr.Length : length;
for (int i = 0 ; i < cnt ; i++) {
buffer[bufferIndex + i] = strBldr[i];
}
// Remove the characters we have already returned
strBldr.Remove(0, cnt);
_charsRemoved += (long)cnt;
return (long)cnt;
}
// This method duplicates the work of XmlWriter.WriteNode except that it reads one element at a time
// instead of reading the entire node like XmlWriter.
private void WriteXmlElement() {
if (_xmlReader.EOF)
return;
bool canReadChunk = _xmlReader.CanReadValueChunk;
char[] writeNodeBuffer = null;
// Constants
const int WriteNodeBufferSize = 1024;
_xmlReader.Read();
switch (_xmlReader.NodeType) {
case XmlNodeType.Element:
_xmlWriter.WriteStartElement(_xmlReader.Prefix, _xmlReader.LocalName, _xmlReader.NamespaceURI);
_xmlWriter.WriteAttributes(_xmlReader, true);
if (_xmlReader.IsEmptyElement) {
_xmlWriter.WriteEndElement();
break;
}
break;
case XmlNodeType.Text:
if (canReadChunk) {
if (writeNodeBuffer == null) {
writeNodeBuffer = new char[WriteNodeBufferSize];
}
int read;
while ((read = _xmlReader.ReadValueChunk(writeNodeBuffer, 0, WriteNodeBufferSize)) > 0) {
_xmlWriter.WriteChars(writeNodeBuffer, 0, read);
}
}
else {
_xmlWriter.WriteString(_xmlReader.Value);
}
break;
case XmlNodeType.Whitespace:
case XmlNodeType.SignificantWhitespace:
_xmlWriter.WriteWhitespace(_xmlReader.Value);
break;
case XmlNodeType.CDATA:
_xmlWriter.WriteCData(_xmlReader.Value);
break;
case XmlNodeType.EntityReference:
_xmlWriter.WriteEntityRef(_xmlReader.Name);
break;
case XmlNodeType.XmlDeclaration:
case XmlNodeType.ProcessingInstruction:
_xmlWriter.WriteProcessingInstruction(_xmlReader.Name, _xmlReader.Value);
break;
case XmlNodeType.DocumentType:
_xmlWriter.WriteDocType(_xmlReader.Name, _xmlReader.GetAttribute("PUBLIC"), _xmlReader.GetAttribute("SYSTEM"), _xmlReader.Value);
break;
case XmlNodeType.Comment:
_xmlWriter.WriteComment(_xmlReader.Value);
break;
case XmlNodeType.EndElement:
_xmlWriter.WriteFullEndElement();
break;
}
_xmlWriter.Flush();
}
}
}
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