| 1 | /* |
| 2 | |
| 3 | Derby - Class org.apache.derby.impl.store.raw.log.ChecksumOperation |
| 4 | |
| 5 | Copyright 1997, 2004 The Apache Software Foundation or its licensors, as applicable. |
| 6 | |
| 7 | Licensed under the Apache License, Version 2.0 (the "License"); |
| 8 | you may not use this file except in compliance with the License. |
| 9 | You may obtain a copy of the License at |
| 10 | |
| 11 | http://www.apache.org/licenses/LICENSE-2.0 |
| 12 | |
| 13 | Unless required by applicable law or agreed to in writing, software |
| 14 | distributed under the License is distributed on an "AS IS" BASIS, |
| 15 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 16 | See the License for the specific language governing permissions and |
| 17 | limitations under the License. |
| 18 | |
| 19 | */ |
| 20 | |
| 21 | package org.apache.derby.impl.store.raw.log; |
| 22 | |
| 23 | import org.apache.derby.iapi.services.sanity.SanityManager; |
| 24 | import org.apache.derby.iapi.services.io.Formatable; |
| 25 | import org.apache.derby.iapi.services.io.FormatIdUtil; |
| 26 | import org.apache.derby.iapi.services.io.StoredFormatIds; |
| 27 | import org.apache.derby.catalog.UUID; |
| 28 | |
| 29 | import org.apache.derby.iapi.store.raw.Transaction; |
| 30 | import org.apache.derby.iapi.store.raw.Loggable; |
| 31 | import org.apache.derby.iapi.store.raw.log.LogInstant; |
| 32 | import org.apache.derby.iapi.store.raw.log.LogFactory; |
| 33 | import org.apache.derby.iapi.store.raw.xact.RawTransaction; |
| 34 | |
| 35 | import org.apache.derby.iapi.error.StandardException; |
| 36 | |
| 37 | import org.apache.derby.iapi.services.io.CompressedNumber; |
| 38 | import org.apache.derby.iapi.util.ByteArray; |
| 39 | |
| 40 | import java.io.Externalizable; |
| 41 | import java.io.OutputStream; |
| 42 | import java.io.InputStream; |
| 43 | import java.io.ObjectInput; |
| 44 | import java.io.ObjectOutput; |
| 45 | import java.io.IOException; |
| 46 | import org.apache.derby.iapi.services.io.LimitObjectInput; |
| 47 | |
| 48 | import java.util.zip.Checksum; |
| 49 | import java.util.zip.CRC32; |
| 50 | |
| 51 | |
| 52 | /** |
| 53 | A Log Operation that represents a checksum for a group of log records |
| 54 | that are written to the tranaction log file. |
| 55 | |
| 56 | <PRE> |
| 57 | @format_id LOGOP_CHECKSUM |
| 58 | the formatId is written by FormatIdOutputStream when this object is |
| 59 | written out by writeObject |
| 60 | @purpose checksum one or more log records while writing to disk |
| 61 | @upgrade |
| 62 | @disk_layout |
| 63 | checksumAlgo(byte) the checksum algorithm |
| 64 | checksumValue(long) the checksum value |
| 65 | dataLength(int) number of bytes that the checksum is calculated |
| 66 | @end_format |
| 67 | </PRE> |
| 68 | |
| 69 | @author Suresh Thalamati |
| 70 | @see Loggable |
| 71 | */ |
| 72 | |
| 73 | public class ChecksumOperation implements Loggable |
| 74 | { |
| 75 | |
| 76 | private byte checksumAlgo; |
| 77 | private long checksumValue; |
| 78 | private int dataLength; |
| 79 | private Checksum checksum; |
| 80 | |
| 81 | /* |
| 82 | * constant values for algorithm that are used to perform the checksum. |
| 83 | */ |
| 84 | public static final byte CRC32_ALGORITHM = (byte) 0x1; //java.util.zip.CRC32 |
| 85 | |
| 86 | private static final int formatLength = FormatIdUtil.getFormatIdByteLength(StoredFormatIds.LOGOP_CHECKSUM); |
| 87 | |
| 88 | public void init() |
| 89 | { |
| 90 | this.checksumAlgo = CRC32_ALGORITHM; |
| 91 | initializeChecksumAlgo(); |
| 92 | dataLength = 0; |
| 93 | } |
| 94 | |
| 95 | |
| 96 | // update the checksum |
| 97 | protected void update(byte[] buf, int off, int len) |
| 98 | { |
| 99 | checksum.update(buf, off , len); |
| 100 | dataLength += len; |
| 101 | } |
| 102 | |
| 103 | |
| 104 | // reset the checksum |
| 105 | protected void reset() |
| 106 | { |
| 107 | checksum.reset(); |
| 108 | dataLength = 0; |
| 109 | } |
| 110 | |
| 111 | |
| 112 | private void initializeChecksumAlgo() |
| 113 | { |
| 114 | if(checksumAlgo == CRC32_ALGORITHM) |
| 115 | this.checksum = new CRC32(); |
| 116 | } |
| 117 | |
| 118 | |
| 119 | /* |
| 120 | * Formatable methods |
| 121 | */ |
| 122 | |
| 123 | // no-arg constructor, required by Formatable |
| 124 | public ChecksumOperation() { super();} |
| 125 | |
| 126 | public void writeExternal(ObjectOutput out) throws IOException |
| 127 | { |
| 128 | checksumValue = checksum.getValue(); |
| 129 | out.writeByte(checksumAlgo); |
| 130 | out.writeInt(dataLength); |
| 131 | out.writeLong(checksumValue); |
| 132 | } |
| 133 | |
| 134 | public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException |
| 135 | { |
| 136 | checksumAlgo = (byte) in.readUnsignedByte(); |
| 137 | dataLength = in.readInt(); |
| 138 | checksumValue = in.readLong(); |
| 139 | initializeChecksumAlgo(); |
| 140 | } |
| 141 | |
| 142 | |
| 143 | public int getStoredSize() |
| 144 | { |
| 145 | return formatLength + 1 + 4 + 8; |
| 146 | } |
| 147 | |
| 148 | |
| 149 | |
| 150 | /** |
| 151 | Return my format identifier. |
| 152 | */ |
| 153 | public int getTypeFormatId() { |
| 154 | return StoredFormatIds.LOGOP_CHECKSUM; |
| 155 | } |
| 156 | |
| 157 | |
| 158 | |
| 159 | |
| 160 | |
| 161 | /** |
| 162 | Loggable methods |
| 163 | */ |
| 164 | |
| 165 | /** |
| 166 | * Nothing to do for the checksum log record because it does need to be |
| 167 | * applied during redo. |
| 168 | */ |
| 169 | public void doMe(Transaction xact, LogInstant instant, LimitObjectInput in) throws StandardException |
| 170 | { |
| 171 | } |
| 172 | |
| 173 | /** |
| 174 | the default for prepared log is always null for all the operations |
| 175 | that don't have optionalData. If an operation has optional data, |
| 176 | the operation need to prepare the optional data for this method. |
| 177 | |
| 178 | Checksum has no optional data to write out |
| 179 | |
| 180 | |
| 181 | */ |
| 182 | public ByteArray getPreparedLog() |
| 183 | { |
| 184 | return (ByteArray) null; |
| 185 | } |
| 186 | |
| 187 | /** |
| 188 | Checksum does not need to be redone, it is used to just verify that |
| 189 | log records are written completely. |
| 190 | */ |
| 191 | public boolean needsRedo(Transaction xact) |
| 192 | { |
| 193 | return false; |
| 194 | } |
| 195 | |
| 196 | |
| 197 | /** |
| 198 | Checksum has no resources to release |
| 199 | */ |
| 200 | public void releaseResource(Transaction xact) |
| 201 | {} |
| 202 | |
| 203 | /** |
| 204 | Checksum is a raw store operation |
| 205 | */ |
| 206 | public int group() |
| 207 | { |
| 208 | return Loggable.RAWSTORE | Loggable.CHECKSUM; |
| 209 | } |
| 210 | |
| 211 | |
| 212 | |
| 213 | |
| 214 | /** |
| 215 | * Access attributes of the checksum log record |
| 216 | */ |
| 217 | |
| 218 | protected int getDataLength() |
| 219 | { |
| 220 | return dataLength; |
| 221 | } |
| 222 | |
| 223 | |
| 224 | protected boolean isChecksumValid(byte[] data, int off , int length) |
| 225 | { |
| 226 | checksum.reset(); |
| 227 | checksum.update(data , off , length); |
| 228 | return checksum.getValue()== checksumValue; |
| 229 | |
| 230 | } |
| 231 | |
| 232 | |
| 233 | /** |
| 234 | DEBUG: Print self. |
| 235 | */ |
| 236 | public String toString() |
| 237 | { |
| 238 | if (SanityManager.DEBUG) |
| 239 | { |
| 240 | StringBuffer str = new StringBuffer(200) |
| 241 | .append("Checksum Operation ") |
| 242 | .append(" algorithm = ") |
| 243 | .append(checksumAlgo) |
| 244 | .append(" value = ") |
| 245 | .append(checksumValue) |
| 246 | .append(" data length= ").append(dataLength); |
| 247 | |
| 248 | return str.toString(); |
| 249 | } |
| 250 | else |
| 251 | return null; |
| 252 | } |
| 253 | } |
| 254 | |
| 255 | |
| 256 | |
| 257 | |
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