com.mysql.cj.protocol.a.result.BinaryBufferRow Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of mysql-connector-java
Show all versions of mysql-connector-java
JDBC Type 4 driver for MySQL
/*
* Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License, version 2.0, as published by the
* Free Software Foundation.
*
* This program is also distributed with certain software (including but not
* limited to OpenSSL) that is licensed under separate terms, as designated in a
* particular file or component or in included license documentation. The
* authors of MySQL hereby grant you an additional permission to link the
* program and your derivative works with the separately licensed software that
* they have included with MySQL.
*
* Without limiting anything contained in the foregoing, this file, which is
* part of MySQL Connector/J, is also subject to the Universal FOSS Exception,
* version 1.0, a copy of which can be found at
* http://oss.oracle.com/licenses/universal-foss-exception.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
* for more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package com.mysql.cj.protocol.a.result;
import com.mysql.cj.Messages;
import com.mysql.cj.MysqlType;
import com.mysql.cj.exceptions.ExceptionFactory;
import com.mysql.cj.exceptions.ExceptionInterceptor;
import com.mysql.cj.exceptions.WrongArgumentException;
import com.mysql.cj.protocol.ColumnDefinition;
import com.mysql.cj.protocol.ValueDecoder;
import com.mysql.cj.protocol.a.NativeConstants.IntegerDataType;
import com.mysql.cj.protocol.a.NativeConstants.StringLengthDataType;
import com.mysql.cj.protocol.a.NativeConstants.StringSelfDataType;
import com.mysql.cj.protocol.a.NativePacketPayload;
import com.mysql.cj.protocol.a.NativeUtils;
import com.mysql.cj.result.Row;
import com.mysql.cj.result.ValueFactory;
/**
* A BufferRow implementation that holds one row packet from a server-side prepared statement (which is re-used by the driver,
* and thus saves memory allocations), and tries when possible to avoid allocations to break out the results as individual byte[]s.
* Rows from a server-side prepared statement are encoded differently, so we have different ways of finding where each column is, and
* unpacking them.
*
* (this isn't possible when doing things like reading floating point values).
*/
public class BinaryBufferRow extends AbstractBufferRow {
/**
* The home position before the is-null bitmask for server-side prepared statement result sets
*/
private int preNullBitmaskHomePosition = 0;
/**
* If binary-encoded, the NULL status of each column is at the beginning of the row, so we
*/
private boolean[] isNull;
public BinaryBufferRow(NativePacketPayload buf, ColumnDefinition cd, ExceptionInterceptor exceptionInterceptor, ValueDecoder valueDecoder) {
super(exceptionInterceptor);
this.rowFromServer = buf;
this.homePosition = this.rowFromServer.getPosition();
this.preNullBitmaskHomePosition = this.homePosition;
this.valueDecoder = valueDecoder;
if (cd.getFields() != null) {
setMetadata(cd);
}
}
@Override
public boolean isBinaryEncoded() {
return true;
}
@Override
protected int findAndSeekToOffset(int index) {
if (index == 0) {
this.lastRequestedIndex = 0;
this.lastRequestedPos = this.homePosition;
this.rowFromServer.setPosition(this.homePosition);
return 0;
}
if (index == this.lastRequestedIndex) {
this.rowFromServer.setPosition(this.lastRequestedPos);
return this.lastRequestedPos;
}
int startingIndex = 0;
if (index > this.lastRequestedIndex) {
if (this.lastRequestedIndex >= 0) {
startingIndex = this.lastRequestedIndex;
} else {
// First-time "scan"
startingIndex = 0;
this.lastRequestedPos = this.homePosition;
}
this.rowFromServer.setPosition(this.lastRequestedPos);
} else {
this.rowFromServer.setPosition(this.homePosition);
}
for (int i = startingIndex; i < index; i++) {
if (this.isNull[i]) {
continue;
}
int type = this.metadata.getFields()[i].getMysqlTypeId();
if (type != MysqlType.FIELD_TYPE_NULL) {
int length = NativeUtils.getBinaryEncodedLength(this.metadata.getFields()[i].getMysqlTypeId());
if (length == 0) {
this.rowFromServer.skipBytes(StringSelfDataType.STRING_LENENC);
} else if (length == -1) {
throw ExceptionFactory.createException(Messages.getString("MysqlIO.97", new Object[] { type, i + 1, this.metadata.getFields().length }),
this.exceptionInterceptor);
} else {
int curPosition = this.rowFromServer.getPosition();
this.rowFromServer.setPosition(curPosition + length);
}
}
}
this.lastRequestedIndex = index;
this.lastRequestedPos = this.rowFromServer.getPosition();
return this.lastRequestedPos;
}
@Override
public byte[] getBytes(int index) {
findAndSeekToOffset(index);
if (this.getNull(index)) {
return null;
}
int type = this.metadata.getFields()[index].getMysqlTypeId();
switch (type) {
case MysqlType.FIELD_TYPE_NULL:
return null;
case MysqlType.FIELD_TYPE_TINY:
return this.rowFromServer.readBytes(StringLengthDataType.STRING_FIXED, 1);
default:
int length = NativeUtils.getBinaryEncodedLength(type);
if (length == 0) {
return this.rowFromServer.readBytes(StringSelfDataType.STRING_LENENC);
} else if (length == -1) {
throw ExceptionFactory.createException(Messages.getString("MysqlIO.97", new Object[] { type, index + 1, this.metadata.getFields().length }),
this.exceptionInterceptor);
} else {
return this.rowFromServer.readBytes(StringLengthDataType.STRING_FIXED, length);
}
}
}
/**
* Check whether a column is NULL and update the 'wasNull' status.
*/
@Override
public boolean getNull(int columnIndex) {
this.wasNull = this.isNull[columnIndex];
return this.wasNull;
}
@Override
public Row setMetadata(ColumnDefinition f) {
super.setMetadata(f);
setupIsNullBitmask();
return this;
}
/**
* Unpacks the bitmask at the head of the row packet that tells us what
* columns hold null values, and sets the "home" position directly after the
* bitmask.
*/
private void setupIsNullBitmask() {
if (this.isNull != null) {
return; // we've already done this
}
this.rowFromServer.setPosition(this.preNullBitmaskHomePosition);
int len = this.metadata.getFields().length;
int nullCount = (len + 9) / 8;
byte[] nullBitMask = this.rowFromServer.readBytes(StringLengthDataType.STRING_FIXED, nullCount);
this.homePosition = this.rowFromServer.getPosition();
this.isNull = new boolean[len];
int nullMaskPos = 0;
int bit = 4; // first two bits are reserved for future use
for (int i = 0; i < len; i++) {
this.isNull[i] = ((nullBitMask[nullMaskPos] & bit) != 0);
if (((bit <<= 1) & 255) == 0) {
bit = 1; /* To next byte */
nullMaskPos++;
}
}
}
/**
* Implementation of getValue() based on the underlying Buffer object. Delegate to superclass for decoding.
*/
@Override
public T getValue(int columnIndex, ValueFactory vf) {
findAndSeekToOffset(columnIndex);
// field length is type-specific in binary-encoded results
int type = this.metadata.getFields()[columnIndex].getMysqlTypeId();
int length = NativeUtils.getBinaryEncodedLength(type);
if (!getNull(columnIndex)) {
if (length == 0) {
length = (int) this.rowFromServer.readInteger(IntegerDataType.INT_LENENC);
} else if (length == -1) {
throw ExceptionFactory.createException(
Messages.getString("MysqlIO.97", new Object[] { type, columnIndex + 1, this.metadata.getFields().length }), this.exceptionInterceptor);
}
}
return getValueFromBytes(columnIndex, this.rowFromServer.getByteBuffer(), this.rowFromServer.getPosition(), length, vf);
}
@Override
public void setBytes(int columnIndex, byte[] value) {
byte[] backup = null;
int backupLength = 0;
// backup the rest of bytes
if (columnIndex + 1 < this.metadata.getFields().length) {
findAndSeekToOffset(columnIndex + 1);
backupLength = this.rowFromServer.getPayloadLength() - this.rowFromServer.getPosition();
backup = new byte[backupLength];
System.arraycopy(this.rowFromServer.getByteBuffer(), this.rowFromServer.getPosition(), backup, 0, backupLength);
}
// write the replacement value
findAndSeekToOffset(columnIndex);
this.rowFromServer.setPayloadLength(this.rowFromServer.getPosition());
if (value == null) {
this.metadata.getFields()[columnIndex].setMysqlTypeId(MysqlType.FIELD_TYPE_NULL);
} else {
int type = this.metadata.getFields()[columnIndex].getMysqlTypeId();
int length = NativeUtils.getBinaryEncodedLength(type);
if (length == 0) {
this.rowFromServer.writeBytes(StringSelfDataType.STRING_LENENC, value);
} else if (length == -1) {
throw ExceptionFactory.createException(
Messages.getString("MysqlIO.97", new Object[] { type, columnIndex + 1, this.metadata.getFields().length }), this.exceptionInterceptor);
} else {
// write leading zeroes if value length < required length
if (length != value.length) {
throw ExceptionFactory.createException(WrongArgumentException.class, "Value length doesn't match the expected one for type " + type,
this.exceptionInterceptor);
}
// write value
this.rowFromServer.writeBytes(StringLengthDataType.STRING_FIXED, value);
}
}
if (backup != null) {
this.rowFromServer.writeBytes(StringLengthDataType.STRING_FIXED, backup);
}
}
}