1 | /** |
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2 | * Licensed to the Apache Software Foundation (ASF) under one or more |
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3 | * contributor license agreements. See the NOTICE file distributed with this |
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4 | * work for additional information regarding copyright ownership. The ASF |
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5 | * licenses this file to you under the Apache License, Version 2.0 (the |
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6 | * "License"); you may not use this file except in compliance with the License. |
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7 | * You may obtain a copy of the License at |
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8 | * |
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9 | * http://www.apache.org/licenses/LICENSE-2.0 |
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10 | * |
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11 | * Unless required by applicable law or agreed to in writing, software |
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12 | * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
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13 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
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14 | * License for the specific language governing permissions and limitations under |
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15 | * the License. |
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16 | */ |
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17 | |
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18 | package org.apache.hadoop.io.file.tfile; |
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19 | |
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20 | import java.io.Closeable; |
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21 | import java.io.DataInput; |
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22 | import java.io.DataInputStream; |
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23 | import java.io.DataOutput; |
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24 | import java.io.DataOutputStream; |
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25 | import java.io.IOException; |
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26 | import java.io.InputStream; |
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27 | import java.io.OutputStream; |
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28 | import java.util.ArrayList; |
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29 | import java.util.Arrays; |
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30 | import java.util.Map; |
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31 | import java.util.TreeMap; |
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32 | |
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33 | import org.apache.commons.logging.Log; |
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34 | import org.apache.commons.logging.LogFactory; |
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35 | import org.apache.hadoop.conf.Configuration; |
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36 | import org.apache.hadoop.fs.FSDataInputStream; |
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37 | import org.apache.hadoop.fs.FSDataOutputStream; |
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38 | import org.apache.hadoop.io.BytesWritable; |
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39 | import org.apache.hadoop.io.compress.Compressor; |
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40 | import org.apache.hadoop.io.compress.Decompressor; |
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41 | import org.apache.hadoop.io.file.tfile.CompareUtils.Scalar; |
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42 | import org.apache.hadoop.io.file.tfile.CompareUtils.ScalarComparator; |
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43 | import org.apache.hadoop.io.file.tfile.CompareUtils.ScalarLong; |
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44 | import org.apache.hadoop.io.file.tfile.Compression.Algorithm; |
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45 | import org.apache.hadoop.io.file.tfile.Utils.Version; |
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46 | |
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47 | /** |
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48 | * Block Compressed file, the underlying physical storage layer for TFile. |
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49 | * BCFile provides the basic block level compression for the data block and meta |
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50 | * blocks. It is separated from TFile as it may be used for other |
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51 | * block-compressed file implementation. |
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52 | */ |
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53 | final class BCFile { |
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54 | // the current version of BCFile impl, increment them (major or minor) made |
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55 | // enough changes |
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56 | static final Version API_VERSION = new Version((short) 1, (short) 0); |
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57 | static final Log LOG = LogFactory.getLog(BCFile.class); |
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58 | |
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59 | /** |
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60 | * Prevent the instantiation of BCFile objects. |
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61 | */ |
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62 | private BCFile() { |
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63 | // nothing |
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64 | } |
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65 | |
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66 | /** |
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67 | * BCFile writer, the entry point for creating a new BCFile. |
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68 | */ |
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69 | static public class Writer implements Closeable { |
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70 | private final FSDataOutputStream out; |
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71 | private final Configuration conf; |
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72 | // the single meta block containing index of compressed data blocks |
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73 | final DataIndex dataIndex; |
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74 | // index for meta blocks |
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75 | final MetaIndex metaIndex; |
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76 | boolean blkInProgress = false; |
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77 | private boolean metaBlkSeen = false; |
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78 | private boolean closed = false; |
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79 | long errorCount = 0; |
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80 | // reusable buffers. |
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81 | private BytesWritable fsOutputBuffer; |
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82 | |
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83 | /** |
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84 | * Call-back interface to register a block after a block is closed. |
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85 | */ |
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86 | private static interface BlockRegister { |
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87 | /** |
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88 | * Register a block that is fully closed. |
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89 | * |
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90 | * @param raw |
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91 | * The size of block in terms of uncompressed bytes. |
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92 | * @param offsetStart |
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93 | * The start offset of the block. |
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94 | * @param offsetEnd |
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95 | * One byte after the end of the block. Compressed block size is |
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96 | * offsetEnd - offsetStart. |
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97 | */ |
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98 | public void register(long raw, long offsetStart, long offsetEnd); |
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99 | } |
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100 | |
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101 | /** |
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102 | * Intermediate class that maintain the state of a Writable Compression |
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103 | * Block. |
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104 | */ |
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105 | private static final class WBlockState { |
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106 | private final Algorithm compressAlgo; |
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107 | private Compressor compressor; // !null only if using native |
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108 | // Hadoop compression |
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109 | private final FSDataOutputStream fsOut; |
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110 | private final long posStart; |
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111 | private final SimpleBufferedOutputStream fsBufferedOutput; |
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112 | private OutputStream out; |
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113 | |
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114 | /** |
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115 | * @param compressionAlgo |
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116 | * The compression algorithm to be used to for compression. |
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117 | * @throws IOException |
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118 | */ |
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119 | public WBlockState(Algorithm compressionAlgo, FSDataOutputStream fsOut, |
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120 | BytesWritable fsOutputBuffer, Configuration conf) throws IOException { |
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121 | this.compressAlgo = compressionAlgo; |
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122 | this.fsOut = fsOut; |
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123 | this.posStart = fsOut.getPos(); |
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124 | |
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125 | fsOutputBuffer.setCapacity(TFile.getFSOutputBufferSize(conf)); |
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126 | |
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127 | this.fsBufferedOutput = |
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128 | new SimpleBufferedOutputStream(this.fsOut, fsOutputBuffer.get()); |
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129 | this.compressor = compressAlgo.getCompressor(); |
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130 | |
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131 | try { |
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132 | this.out = |
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133 | compressionAlgo.createCompressionStream(fsBufferedOutput, |
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134 | compressor, 0); |
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135 | } catch (IOException e) { |
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136 | compressAlgo.returnCompressor(compressor); |
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137 | throw e; |
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138 | } |
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139 | } |
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140 | |
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141 | /** |
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142 | * Get the output stream for BlockAppender's consumption. |
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143 | * |
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144 | * @return the output stream suitable for writing block data. |
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145 | */ |
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146 | OutputStream getOutputStream() { |
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147 | return out; |
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148 | } |
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149 | |
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150 | /** |
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151 | * Get the current position in file. |
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152 | * |
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153 | * @return The current byte offset in underlying file. |
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154 | * @throws IOException |
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155 | */ |
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156 | long getCurrentPos() throws IOException { |
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157 | return fsOut.getPos() + fsBufferedOutput.size(); |
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158 | } |
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159 | |
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160 | long getStartPos() { |
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161 | return posStart; |
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162 | } |
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163 | |
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164 | /** |
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165 | * Current size of compressed data. |
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166 | * |
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167 | * @return |
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168 | * @throws IOException |
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169 | */ |
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170 | long getCompressedSize() throws IOException { |
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171 | long ret = getCurrentPos() - posStart; |
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172 | return ret; |
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173 | } |
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174 | |
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175 | /** |
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176 | * Finishing up the current block. |
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177 | */ |
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178 | public void finish() throws IOException { |
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179 | try { |
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180 | if (out != null) { |
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181 | out.flush(); |
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182 | out = null; |
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183 | } |
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184 | } finally { |
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185 | compressAlgo.returnCompressor(compressor); |
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186 | compressor = null; |
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187 | } |
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188 | } |
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189 | } |
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190 | |
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191 | /** |
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192 | * Access point to stuff data into a block. |
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193 | * |
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194 | * TODO: Change DataOutputStream to something else that tracks the size as |
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195 | * long instead of int. Currently, we will wrap around if the row block size |
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196 | * is greater than 4GB. |
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197 | */ |
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198 | public class BlockAppender extends DataOutputStream { |
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199 | private final BlockRegister blockRegister; |
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200 | private final WBlockState wBlkState; |
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201 | @SuppressWarnings("hiding") |
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202 | private boolean closed = false; |
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203 | |
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204 | /** |
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205 | * Constructor |
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206 | * |
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207 | * @param register |
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208 | * the block register, which is called when the block is closed. |
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209 | * @param wbs |
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210 | * The writable compression block state. |
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211 | */ |
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212 | BlockAppender(BlockRegister register, WBlockState wbs) { |
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213 | super(wbs.getOutputStream()); |
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214 | this.blockRegister = register; |
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215 | this.wBlkState = wbs; |
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216 | } |
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217 | |
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218 | /** |
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219 | * Get the raw size of the block. |
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220 | * |
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221 | * @return the number of uncompressed bytes written through the |
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222 | * BlockAppender so far. |
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223 | * @throws IOException |
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224 | */ |
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225 | public long getRawSize() throws IOException { |
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226 | /** |
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227 | * Expecting the size() of a block not exceeding 4GB. Assuming the |
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228 | * size() will wrap to negative integer if it exceeds 2GB. |
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229 | */ |
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230 | return size() & 0x00000000ffffffffL; |
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231 | } |
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232 | |
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233 | /** |
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234 | * Get the compressed size of the block in progress. |
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235 | * |
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236 | * @return the number of compressed bytes written to the underlying FS |
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237 | * file. The size may be smaller than actual need to compress the |
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238 | * all data written due to internal buffering inside the |
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239 | * compressor. |
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240 | * @throws IOException |
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241 | */ |
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242 | public long getCompressedSize() throws IOException { |
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243 | return wBlkState.getCompressedSize(); |
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244 | } |
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245 | |
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246 | @Override |
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247 | public void flush() { |
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248 | // The down stream is a special kind of stream that finishes a |
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249 | // compression block upon flush. So we disable flush() here. |
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250 | } |
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251 | |
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252 | /** |
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253 | * Signaling the end of write to the block. The block register will be |
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254 | * called for registering the finished block. |
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255 | */ |
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256 | @Override |
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257 | public void close() throws IOException { |
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258 | if (closed == true) { |
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259 | return; |
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260 | } |
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261 | try { |
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262 | ++errorCount; |
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263 | wBlkState.finish(); |
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264 | blockRegister.register(getRawSize(), wBlkState.getStartPos(), |
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265 | wBlkState.getCurrentPos()); |
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266 | --errorCount; |
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267 | } finally { |
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268 | closed = true; |
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269 | blkInProgress = false; |
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270 | } |
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271 | } |
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272 | } |
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273 | |
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274 | /** |
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275 | * Constructor |
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276 | * |
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277 | * @param fout |
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278 | * FS output stream. |
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279 | * @param compressionName |
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280 | * Name of the compression algorithm, which will be used for all |
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281 | * data blocks. |
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282 | * @throws IOException |
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283 | * @see Compression#getSupportedAlgorithms |
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284 | */ |
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285 | public Writer(FSDataOutputStream fout, String compressionName, |
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286 | Configuration conf) throws IOException { |
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287 | if (fout.getPos() != 0) { |
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288 | throw new IOException("Output file not at zero offset."); |
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289 | } |
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290 | |
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291 | this.out = fout; |
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292 | this.conf = conf; |
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293 | dataIndex = new DataIndex(compressionName); |
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294 | metaIndex = new MetaIndex(); |
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295 | fsOutputBuffer = new BytesWritable(); |
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296 | Magic.write(fout); |
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297 | } |
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298 | |
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299 | /** |
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300 | * Close the BCFile Writer. Attempting to use the Writer after calling |
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301 | * <code>close</code> is not allowed and may lead to undetermined results. |
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302 | */ |
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303 | public void close() throws IOException { |
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304 | if (closed == true) { |
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305 | return; |
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306 | } |
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307 | |
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308 | try { |
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309 | if (errorCount == 0) { |
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310 | if (blkInProgress == true) { |
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311 | throw new IllegalStateException( |
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312 | "Close() called with active block appender."); |
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313 | } |
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314 | |
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315 | // add metaBCFileIndex to metaIndex as the last meta block |
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316 | BlockAppender appender = |
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317 | prepareMetaBlock(DataIndex.BLOCK_NAME, |
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318 | getDefaultCompressionAlgorithm()); |
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319 | try { |
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320 | dataIndex.write(appender); |
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321 | } finally { |
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322 | appender.close(); |
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323 | } |
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324 | |
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325 | long offsetIndexMeta = out.getPos(); |
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326 | metaIndex.write(out); |
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327 | |
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328 | // Meta Index and the trailing section are written out directly. |
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329 | out.writeLong(offsetIndexMeta); |
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330 | |
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331 | API_VERSION.write(out); |
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332 | Magic.write(out); |
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333 | out.flush(); |
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334 | } |
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335 | } finally { |
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336 | closed = true; |
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337 | } |
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338 | } |
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339 | |
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340 | private Algorithm getDefaultCompressionAlgorithm() { |
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341 | return dataIndex.getDefaultCompressionAlgorithm(); |
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342 | } |
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343 | |
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344 | private BlockAppender prepareMetaBlock(String name, Algorithm compressAlgo) |
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345 | throws IOException, MetaBlockAlreadyExists { |
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346 | if (blkInProgress == true) { |
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347 | throw new IllegalStateException( |
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348 | "Cannot create Meta Block until previous block is closed."); |
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349 | } |
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350 | |
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351 | if (metaIndex.getMetaByName(name) != null) { |
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352 | throw new MetaBlockAlreadyExists("name=" + name); |
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353 | } |
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354 | |
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355 | MetaBlockRegister mbr = new MetaBlockRegister(name, compressAlgo); |
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356 | WBlockState wbs = |
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357 | new WBlockState(compressAlgo, out, fsOutputBuffer, conf); |
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358 | BlockAppender ba = new BlockAppender(mbr, wbs); |
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359 | blkInProgress = true; |
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360 | metaBlkSeen = true; |
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361 | return ba; |
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362 | } |
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363 | |
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364 | /** |
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365 | * Create a Meta Block and obtain an output stream for adding data into the |
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366 | * block. There can only be one BlockAppender stream active at any time. |
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367 | * Regular Blocks may not be created after the first Meta Blocks. The caller |
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368 | * must call BlockAppender.close() to conclude the block creation. |
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369 | * |
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370 | * @param name |
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371 | * The name of the Meta Block. The name must not conflict with |
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372 | * existing Meta Blocks. |
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373 | * @param compressionName |
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374 | * The name of the compression algorithm to be used. |
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375 | * @return The BlockAppender stream |
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376 | * @throws IOException |
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377 | * @throws MetaBlockAlreadyExists |
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378 | * If the meta block with the name already exists. |
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379 | */ |
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380 | public BlockAppender prepareMetaBlock(String name, String compressionName) |
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381 | throws IOException, MetaBlockAlreadyExists { |
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382 | return prepareMetaBlock(name, Compression |
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383 | .getCompressionAlgorithmByName(compressionName)); |
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384 | } |
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385 | |
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386 | /** |
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387 | * Create a Meta Block and obtain an output stream for adding data into the |
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388 | * block. The Meta Block will be compressed with the same compression |
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389 | * algorithm as data blocks. There can only be one BlockAppender stream |
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390 | * active at any time. Regular Blocks may not be created after the first |
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391 | * Meta Blocks. The caller must call BlockAppender.close() to conclude the |
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392 | * block creation. |
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393 | * |
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394 | * @param name |
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395 | * The name of the Meta Block. The name must not conflict with |
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396 | * existing Meta Blocks. |
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397 | * @return The BlockAppender stream |
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398 | * @throws MetaBlockAlreadyExists |
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399 | * If the meta block with the name already exists. |
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400 | * @throws IOException |
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401 | */ |
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402 | public BlockAppender prepareMetaBlock(String name) throws IOException, |
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403 | MetaBlockAlreadyExists { |
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404 | return prepareMetaBlock(name, getDefaultCompressionAlgorithm()); |
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405 | } |
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406 | |
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407 | /** |
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408 | * Create a Data Block and obtain an output stream for adding data into the |
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409 | * block. There can only be one BlockAppender stream active at any time. |
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410 | * Data Blocks may not be created after the first Meta Blocks. The caller |
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411 | * must call BlockAppender.close() to conclude the block creation. |
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412 | * |
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413 | * @return The BlockAppender stream |
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414 | * @throws IOException |
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415 | */ |
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416 | public BlockAppender prepareDataBlock() throws IOException { |
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417 | if (blkInProgress == true) { |
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418 | throw new IllegalStateException( |
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419 | "Cannot create Data Block until previous block is closed."); |
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420 | } |
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421 | |
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422 | if (metaBlkSeen == true) { |
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423 | throw new IllegalStateException( |
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424 | "Cannot create Data Block after Meta Blocks."); |
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425 | } |
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426 | |
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427 | DataBlockRegister dbr = new DataBlockRegister(); |
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428 | |
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429 | WBlockState wbs = |
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430 | new WBlockState(getDefaultCompressionAlgorithm(), out, |
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431 | fsOutputBuffer, conf); |
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432 | BlockAppender ba = new BlockAppender(dbr, wbs); |
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433 | blkInProgress = true; |
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434 | return ba; |
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435 | } |
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436 | |
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437 | /** |
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438 | * Callback to make sure a meta block is added to the internal list when its |
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439 | * stream is closed. |
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440 | */ |
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441 | private class MetaBlockRegister implements BlockRegister { |
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442 | private final String name; |
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443 | private final Algorithm compressAlgo; |
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444 | |
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445 | MetaBlockRegister(String name, Algorithm compressAlgo) { |
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446 | this.name = name; |
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447 | this.compressAlgo = compressAlgo; |
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448 | } |
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449 | |
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450 | public void register(long raw, long begin, long end) { |
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451 | metaIndex.addEntry(new MetaIndexEntry(name, compressAlgo, |
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452 | new BlockRegion(begin, end - begin, raw))); |
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453 | } |
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454 | } |
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455 | |
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456 | /** |
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457 | * Callback to make sure a data block is added to the internal list when |
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458 | * it's being closed. |
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459 | * |
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460 | */ |
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461 | private class DataBlockRegister implements BlockRegister { |
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462 | DataBlockRegister() { |
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463 | // do nothing |
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464 | } |
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465 | |
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466 | public void register(long raw, long begin, long end) { |
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467 | dataIndex.addBlockRegion(new BlockRegion(begin, end - begin, raw)); |
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468 | } |
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469 | } |
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470 | } |
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471 | |
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472 | /** |
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473 | * BCFile Reader, interface to read the file's data and meta blocks. |
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474 | */ |
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475 | static public class Reader implements Closeable { |
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476 | private final FSDataInputStream in; |
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477 | private final Configuration conf; |
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478 | final DataIndex dataIndex; |
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479 | // Index for meta blocks |
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480 | final MetaIndex metaIndex; |
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481 | final Version version; |
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482 | |
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483 | /** |
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484 | * Intermediate class that maintain the state of a Readable Compression |
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485 | * Block. |
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486 | */ |
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487 | static private final class RBlockState { |
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488 | private final Algorithm compressAlgo; |
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489 | private Decompressor decompressor; |
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490 | private final BlockRegion region; |
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491 | private final InputStream in; |
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492 | |
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493 | public RBlockState(Algorithm compressionAlgo, FSDataInputStream fsin, |
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494 | BlockRegion region, Configuration conf) throws IOException { |
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495 | this.compressAlgo = compressionAlgo; |
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496 | this.region = region; |
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497 | this.decompressor = compressionAlgo.getDecompressor(); |
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498 | |
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499 | try { |
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500 | this.in = |
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501 | compressAlgo |
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502 | .createDecompressionStream(new BoundedRangeFileInputStream( |
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503 | fsin, this.region.getOffset(), this.region |
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504 | .getCompressedSize()), decompressor, TFile |
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505 | .getFSInputBufferSize(conf)); |
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506 | } catch (IOException e) { |
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507 | compressAlgo.returnDecompressor(decompressor); |
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508 | throw e; |
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509 | } |
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510 | } |
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511 | |
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512 | /** |
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513 | * Get the output stream for BlockAppender's consumption. |
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514 | * |
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515 | * @return the output stream suitable for writing block data. |
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516 | */ |
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517 | public InputStream getInputStream() { |
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518 | return in; |
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519 | } |
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520 | |
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521 | public String getCompressionName() { |
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522 | return compressAlgo.getName(); |
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523 | } |
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524 | |
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525 | public BlockRegion getBlockRegion() { |
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526 | return region; |
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527 | } |
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528 | |
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529 | public void finish() throws IOException { |
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530 | try { |
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531 | in.close(); |
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532 | } finally { |
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533 | compressAlgo.returnDecompressor(decompressor); |
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534 | decompressor = null; |
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535 | } |
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536 | } |
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537 | } |
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538 | |
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539 | /** |
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540 | * Access point to read a block. |
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541 | */ |
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542 | public static class BlockReader extends DataInputStream { |
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543 | private final RBlockState rBlkState; |
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544 | private boolean closed = false; |
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545 | |
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546 | BlockReader(RBlockState rbs) { |
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547 | super(rbs.getInputStream()); |
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548 | rBlkState = rbs; |
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549 | } |
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550 | |
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551 | /** |
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552 | * Finishing reading the block. Release all resources. |
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553 | */ |
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554 | @Override |
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555 | public void close() throws IOException { |
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556 | if (closed == true) { |
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557 | return; |
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558 | } |
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559 | try { |
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560 | // Do not set rBlkState to null. People may access stats after calling |
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561 | // close(). |
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562 | rBlkState.finish(); |
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563 | } finally { |
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564 | closed = true; |
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565 | } |
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566 | } |
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567 | |
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568 | /** |
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569 | * Get the name of the compression algorithm used to compress the block. |
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570 | * |
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571 | * @return name of the compression algorithm. |
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572 | */ |
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573 | public String getCompressionName() { |
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574 | return rBlkState.getCompressionName(); |
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575 | } |
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576 | |
---|
577 | /** |
---|
578 | * Get the uncompressed size of the block. |
---|
579 | * |
---|
580 | * @return uncompressed size of the block. |
---|
581 | */ |
---|
582 | public long getRawSize() { |
---|
583 | return rBlkState.getBlockRegion().getRawSize(); |
---|
584 | } |
---|
585 | |
---|
586 | /** |
---|
587 | * Get the compressed size of the block. |
---|
588 | * |
---|
589 | * @return compressed size of the block. |
---|
590 | */ |
---|
591 | public long getCompressedSize() { |
---|
592 | return rBlkState.getBlockRegion().getCompressedSize(); |
---|
593 | } |
---|
594 | |
---|
595 | /** |
---|
596 | * Get the starting position of the block in the file. |
---|
597 | * |
---|
598 | * @return the starting position of the block in the file. |
---|
599 | */ |
---|
600 | public long getStartPos() { |
---|
601 | return rBlkState.getBlockRegion().getOffset(); |
---|
602 | } |
---|
603 | } |
---|
604 | |
---|
605 | /** |
---|
606 | * Constructor |
---|
607 | * |
---|
608 | * @param fin |
---|
609 | * FS input stream. |
---|
610 | * @param fileLength |
---|
611 | * Length of the corresponding file |
---|
612 | * @throws IOException |
---|
613 | */ |
---|
614 | public Reader(FSDataInputStream fin, long fileLength, Configuration conf) |
---|
615 | throws IOException { |
---|
616 | this.in = fin; |
---|
617 | this.conf = conf; |
---|
618 | |
---|
619 | // move the cursor to the beginning of the tail, containing: offset to the |
---|
620 | // meta block index, version and magic |
---|
621 | fin.seek(fileLength - Magic.size() - Version.size() - Long.SIZE |
---|
622 | / Byte.SIZE); |
---|
623 | long offsetIndexMeta = fin.readLong(); |
---|
624 | version = new Version(fin); |
---|
625 | Magic.readAndVerify(fin); |
---|
626 | |
---|
627 | if (!version.compatibleWith(BCFile.API_VERSION)) { |
---|
628 | throw new RuntimeException("Incompatible BCFile fileBCFileVersion."); |
---|
629 | } |
---|
630 | |
---|
631 | // read meta index |
---|
632 | fin.seek(offsetIndexMeta); |
---|
633 | metaIndex = new MetaIndex(fin); |
---|
634 | |
---|
635 | // read data:BCFile.index, the data block index |
---|
636 | BlockReader blockR = getMetaBlock(DataIndex.BLOCK_NAME); |
---|
637 | try { |
---|
638 | dataIndex = new DataIndex(blockR); |
---|
639 | } finally { |
---|
640 | blockR.close(); |
---|
641 | } |
---|
642 | } |
---|
643 | |
---|
644 | /** |
---|
645 | * Get the name of the default compression algorithm. |
---|
646 | * |
---|
647 | * @return the name of the default compression algorithm. |
---|
648 | */ |
---|
649 | public String getDefaultCompressionName() { |
---|
650 | return dataIndex.getDefaultCompressionAlgorithm().getName(); |
---|
651 | } |
---|
652 | |
---|
653 | /** |
---|
654 | * Get version of BCFile file being read. |
---|
655 | * |
---|
656 | * @return version of BCFile file being read. |
---|
657 | */ |
---|
658 | public Version getBCFileVersion() { |
---|
659 | return version; |
---|
660 | } |
---|
661 | |
---|
662 | /** |
---|
663 | * Get version of BCFile API. |
---|
664 | * |
---|
665 | * @return version of BCFile API. |
---|
666 | */ |
---|
667 | public Version getAPIVersion() { |
---|
668 | return API_VERSION; |
---|
669 | } |
---|
670 | |
---|
671 | /** |
---|
672 | * Finishing reading the BCFile. Release all resources. |
---|
673 | */ |
---|
674 | public void close() { |
---|
675 | // nothing to be done now |
---|
676 | } |
---|
677 | |
---|
678 | /** |
---|
679 | * Get the number of data blocks. |
---|
680 | * |
---|
681 | * @return the number of data blocks. |
---|
682 | */ |
---|
683 | public int getBlockCount() { |
---|
684 | return dataIndex.getBlockRegionList().size(); |
---|
685 | } |
---|
686 | |
---|
687 | /** |
---|
688 | * Stream access to a Meta Block. |
---|
689 | * |
---|
690 | * @param name |
---|
691 | * meta block name |
---|
692 | * @return BlockReader input stream for reading the meta block. |
---|
693 | * @throws IOException |
---|
694 | * @throws MetaBlockDoesNotExist |
---|
695 | * The Meta Block with the given name does not exist. |
---|
696 | */ |
---|
697 | public BlockReader getMetaBlock(String name) throws IOException, |
---|
698 | MetaBlockDoesNotExist { |
---|
699 | MetaIndexEntry imeBCIndex = metaIndex.getMetaByName(name); |
---|
700 | if (imeBCIndex == null) { |
---|
701 | throw new MetaBlockDoesNotExist("name=" + name); |
---|
702 | } |
---|
703 | |
---|
704 | BlockRegion region = imeBCIndex.getRegion(); |
---|
705 | return createReader(imeBCIndex.getCompressionAlgorithm(), region); |
---|
706 | } |
---|
707 | |
---|
708 | /** |
---|
709 | * Stream access to a Data Block. |
---|
710 | * |
---|
711 | * @param blockIndex |
---|
712 | * 0-based data block index. |
---|
713 | * @return BlockReader input stream for reading the data block. |
---|
714 | * @throws IOException |
---|
715 | */ |
---|
716 | public BlockReader getDataBlock(int blockIndex) throws IOException { |
---|
717 | if (blockIndex < 0 || blockIndex >= getBlockCount()) { |
---|
718 | throw new IndexOutOfBoundsException(String.format( |
---|
719 | "blockIndex=%d, numBlocks=%d", blockIndex, getBlockCount())); |
---|
720 | } |
---|
721 | |
---|
722 | BlockRegion region = dataIndex.getBlockRegionList().get(blockIndex); |
---|
723 | return createReader(dataIndex.getDefaultCompressionAlgorithm(), region); |
---|
724 | } |
---|
725 | |
---|
726 | private BlockReader createReader(Algorithm compressAlgo, BlockRegion region) |
---|
727 | throws IOException { |
---|
728 | RBlockState rbs = new RBlockState(compressAlgo, in, region, conf); |
---|
729 | return new BlockReader(rbs); |
---|
730 | } |
---|
731 | |
---|
732 | /** |
---|
733 | * Find the smallest Block index whose starting offset is greater than or |
---|
734 | * equal to the specified offset. |
---|
735 | * |
---|
736 | * @param offset |
---|
737 | * User-specific offset. |
---|
738 | * @return the index to the data Block if such block exists; or -1 |
---|
739 | * otherwise. |
---|
740 | */ |
---|
741 | public int getBlockIndexNear(long offset) { |
---|
742 | ArrayList<BlockRegion> list = dataIndex.getBlockRegionList(); |
---|
743 | int idx = |
---|
744 | Utils |
---|
745 | .lowerBound(list, new ScalarLong(offset), new ScalarComparator()); |
---|
746 | |
---|
747 | if (idx == list.size()) { |
---|
748 | return -1; |
---|
749 | } |
---|
750 | |
---|
751 | return idx; |
---|
752 | } |
---|
753 | } |
---|
754 | |
---|
755 | /** |
---|
756 | * Index for all Meta blocks. |
---|
757 | */ |
---|
758 | static class MetaIndex { |
---|
759 | // use a tree map, for getting a meta block entry by name |
---|
760 | final Map<String, MetaIndexEntry> index; |
---|
761 | |
---|
762 | // for write |
---|
763 | public MetaIndex() { |
---|
764 | index = new TreeMap<String, MetaIndexEntry>(); |
---|
765 | } |
---|
766 | |
---|
767 | // for read, construct the map from the file |
---|
768 | public MetaIndex(DataInput in) throws IOException { |
---|
769 | int count = Utils.readVInt(in); |
---|
770 | index = new TreeMap<String, MetaIndexEntry>(); |
---|
771 | |
---|
772 | for (int nx = 0; nx < count; nx++) { |
---|
773 | MetaIndexEntry indexEntry = new MetaIndexEntry(in); |
---|
774 | index.put(indexEntry.getMetaName(), indexEntry); |
---|
775 | } |
---|
776 | } |
---|
777 | |
---|
778 | public void addEntry(MetaIndexEntry indexEntry) { |
---|
779 | index.put(indexEntry.getMetaName(), indexEntry); |
---|
780 | } |
---|
781 | |
---|
782 | public MetaIndexEntry getMetaByName(String name) { |
---|
783 | return index.get(name); |
---|
784 | } |
---|
785 | |
---|
786 | public void write(DataOutput out) throws IOException { |
---|
787 | Utils.writeVInt(out, index.size()); |
---|
788 | |
---|
789 | for (MetaIndexEntry indexEntry : index.values()) { |
---|
790 | indexEntry.write(out); |
---|
791 | } |
---|
792 | } |
---|
793 | } |
---|
794 | |
---|
795 | /** |
---|
796 | * An entry describes a meta block in the MetaIndex. |
---|
797 | */ |
---|
798 | static final class MetaIndexEntry { |
---|
799 | private final String metaName; |
---|
800 | private final Algorithm compressionAlgorithm; |
---|
801 | private final static String defaultPrefix = "data:"; |
---|
802 | |
---|
803 | private final BlockRegion region; |
---|
804 | |
---|
805 | public MetaIndexEntry(DataInput in) throws IOException { |
---|
806 | String fullMetaName = Utils.readString(in); |
---|
807 | if (fullMetaName.startsWith(defaultPrefix)) { |
---|
808 | metaName = |
---|
809 | fullMetaName.substring(defaultPrefix.length(), fullMetaName |
---|
810 | .length()); |
---|
811 | } else { |
---|
812 | throw new IOException("Corrupted Meta region Index"); |
---|
813 | } |
---|
814 | |
---|
815 | compressionAlgorithm = |
---|
816 | Compression.getCompressionAlgorithmByName(Utils.readString(in)); |
---|
817 | region = new BlockRegion(in); |
---|
818 | } |
---|
819 | |
---|
820 | public MetaIndexEntry(String metaName, Algorithm compressionAlgorithm, |
---|
821 | BlockRegion region) { |
---|
822 | this.metaName = metaName; |
---|
823 | this.compressionAlgorithm = compressionAlgorithm; |
---|
824 | this.region = region; |
---|
825 | } |
---|
826 | |
---|
827 | public String getMetaName() { |
---|
828 | return metaName; |
---|
829 | } |
---|
830 | |
---|
831 | public Algorithm getCompressionAlgorithm() { |
---|
832 | return compressionAlgorithm; |
---|
833 | } |
---|
834 | |
---|
835 | public BlockRegion getRegion() { |
---|
836 | return region; |
---|
837 | } |
---|
838 | |
---|
839 | public void write(DataOutput out) throws IOException { |
---|
840 | Utils.writeString(out, defaultPrefix + metaName); |
---|
841 | Utils.writeString(out, compressionAlgorithm.getName()); |
---|
842 | |
---|
843 | region.write(out); |
---|
844 | } |
---|
845 | } |
---|
846 | |
---|
847 | /** |
---|
848 | * Index of all compressed data blocks. |
---|
849 | */ |
---|
850 | static class DataIndex { |
---|
851 | final static String BLOCK_NAME = "BCFile.index"; |
---|
852 | |
---|
853 | private final Algorithm defaultCompressionAlgorithm; |
---|
854 | |
---|
855 | // for data blocks, each entry specifies a block's offset, compressed size |
---|
856 | // and raw size |
---|
857 | private final ArrayList<BlockRegion> listRegions; |
---|
858 | |
---|
859 | // for read, deserialized from a file |
---|
860 | public DataIndex(DataInput in) throws IOException { |
---|
861 | defaultCompressionAlgorithm = |
---|
862 | Compression.getCompressionAlgorithmByName(Utils.readString(in)); |
---|
863 | |
---|
864 | int n = Utils.readVInt(in); |
---|
865 | listRegions = new ArrayList<BlockRegion>(n); |
---|
866 | |
---|
867 | for (int i = 0; i < n; i++) { |
---|
868 | BlockRegion region = new BlockRegion(in); |
---|
869 | listRegions.add(region); |
---|
870 | } |
---|
871 | } |
---|
872 | |
---|
873 | // for write |
---|
874 | public DataIndex(String defaultCompressionAlgorithmName) { |
---|
875 | this.defaultCompressionAlgorithm = |
---|
876 | Compression |
---|
877 | .getCompressionAlgorithmByName(defaultCompressionAlgorithmName); |
---|
878 | listRegions = new ArrayList<BlockRegion>(); |
---|
879 | } |
---|
880 | |
---|
881 | public Algorithm getDefaultCompressionAlgorithm() { |
---|
882 | return defaultCompressionAlgorithm; |
---|
883 | } |
---|
884 | |
---|
885 | public ArrayList<BlockRegion> getBlockRegionList() { |
---|
886 | return listRegions; |
---|
887 | } |
---|
888 | |
---|
889 | public void addBlockRegion(BlockRegion region) { |
---|
890 | listRegions.add(region); |
---|
891 | } |
---|
892 | |
---|
893 | public void write(DataOutput out) throws IOException { |
---|
894 | Utils.writeString(out, defaultCompressionAlgorithm.getName()); |
---|
895 | |
---|
896 | Utils.writeVInt(out, listRegions.size()); |
---|
897 | |
---|
898 | for (BlockRegion region : listRegions) { |
---|
899 | region.write(out); |
---|
900 | } |
---|
901 | } |
---|
902 | } |
---|
903 | |
---|
904 | /** |
---|
905 | * Magic number uniquely identifying a BCFile in the header/footer. |
---|
906 | */ |
---|
907 | static final class Magic { |
---|
908 | private final static byte[] AB_MAGIC_BCFILE = |
---|
909 | { |
---|
910 | // ... total of 16 bytes |
---|
911 | (byte) 0xd1, (byte) 0x11, (byte) 0xd3, (byte) 0x68, (byte) 0x91, |
---|
912 | (byte) 0xb5, (byte) 0xd7, (byte) 0xb6, (byte) 0x39, (byte) 0xdf, |
---|
913 | (byte) 0x41, (byte) 0x40, (byte) 0x92, (byte) 0xba, (byte) 0xe1, |
---|
914 | (byte) 0x50 }; |
---|
915 | |
---|
916 | public static void readAndVerify(DataInput in) throws IOException { |
---|
917 | byte[] abMagic = new byte[size()]; |
---|
918 | in.readFully(abMagic); |
---|
919 | |
---|
920 | // check against AB_MAGIC_BCFILE, if not matching, throw an |
---|
921 | // Exception |
---|
922 | if (!Arrays.equals(abMagic, AB_MAGIC_BCFILE)) { |
---|
923 | throw new IOException("Not a valid BCFile."); |
---|
924 | } |
---|
925 | } |
---|
926 | |
---|
927 | public static void write(DataOutput out) throws IOException { |
---|
928 | out.write(AB_MAGIC_BCFILE); |
---|
929 | } |
---|
930 | |
---|
931 | public static int size() { |
---|
932 | return AB_MAGIC_BCFILE.length; |
---|
933 | } |
---|
934 | } |
---|
935 | |
---|
936 | /** |
---|
937 | * Block region. |
---|
938 | */ |
---|
939 | static final class BlockRegion implements Scalar { |
---|
940 | private final long offset; |
---|
941 | private final long compressedSize; |
---|
942 | private final long rawSize; |
---|
943 | |
---|
944 | public BlockRegion(DataInput in) throws IOException { |
---|
945 | offset = Utils.readVLong(in); |
---|
946 | compressedSize = Utils.readVLong(in); |
---|
947 | rawSize = Utils.readVLong(in); |
---|
948 | } |
---|
949 | |
---|
950 | public BlockRegion(long offset, long compressedSize, long rawSize) { |
---|
951 | this.offset = offset; |
---|
952 | this.compressedSize = compressedSize; |
---|
953 | this.rawSize = rawSize; |
---|
954 | } |
---|
955 | |
---|
956 | public void write(DataOutput out) throws IOException { |
---|
957 | Utils.writeVLong(out, offset); |
---|
958 | Utils.writeVLong(out, compressedSize); |
---|
959 | Utils.writeVLong(out, rawSize); |
---|
960 | } |
---|
961 | |
---|
962 | public long getOffset() { |
---|
963 | return offset; |
---|
964 | } |
---|
965 | |
---|
966 | public long getCompressedSize() { |
---|
967 | return compressedSize; |
---|
968 | } |
---|
969 | |
---|
970 | public long getRawSize() { |
---|
971 | return rawSize; |
---|
972 | } |
---|
973 | |
---|
974 | @Override |
---|
975 | public long magnitude() { |
---|
976 | return offset; |
---|
977 | } |
---|
978 | } |
---|
979 | } |
---|