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a52fde77 | 1 | /******************************************************************************* |
60ae41e1 | 2 | * Copyright (c) 2012, 2014 Ericsson |
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3 | * Copyright (c) 2010, 2011 École Polytechnique de Montréal |
4 | * Copyright (c) 2010, 2011 Alexandre Montplaisir <alexandre.montplaisir@gmail.com> | |
3de60236 | 5 | * |
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6 | * All rights reserved. This program and the accompanying materials are |
7 | * made available under the terms of the Eclipse Public License v1.0 which | |
8 | * accompanies this distribution, and is available at | |
9 | * http://www.eclipse.org/legal/epl-v10.html | |
3de60236 | 10 | * |
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11 | *******************************************************************************/ |
12 | ||
e894a508 | 13 | package org.eclipse.tracecompass.internal.statesystem.core.backend.historytree; |
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14 | |
15 | import java.io.File; | |
16 | import java.io.FileInputStream; | |
17 | import java.io.FileOutputStream; | |
18 | import java.io.IOException; | |
3b7f5abe | 19 | import java.nio.channels.ClosedChannelException; |
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20 | import java.nio.channels.FileChannel; |
21 | ||
49a817d5 MK |
22 | import org.eclipse.tracecompass.internal.statesystem.core.Activator; |
23 | ||
a52fde77 | 24 | /** |
360f899e EB |
25 | * This class abstracts inputs/outputs of the HistoryTree nodes. |
26 | * | |
27 | * It contains all the methods and descriptors to handle reading/writing nodes | |
28 | * to the tree-file on disk and all the caching mechanisms. | |
29 | * | |
49a817d5 MK |
30 | * This abstraction is mainly for code isolation/clarification purposes. Every |
31 | * HistoryTree must contain 1 and only 1 HT_IO element. | |
3de60236 | 32 | * |
ffd0aa67 | 33 | * @author Alexandre Montplaisir |
3de60236 | 34 | * |
a52fde77 AM |
35 | */ |
36 | class HT_IO { | |
360f899e EB |
37 | /* Configuration of the History Tree */ |
38 | private final HTConfig fConfig; | |
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39 | |
40 | /* Fields related to the file I/O */ | |
3de60236 AM |
41 | private final FileInputStream fis; |
42 | private final FileOutputStream fos; | |
43 | private final FileChannel fcIn; | |
44 | private final FileChannel fcOut; | |
a52fde77 | 45 | |
0c1d4577 | 46 | // TODO test/benchmark optimal cache size |
49a817d5 | 47 | private static final int CACHE_SIZE = 256; |
6993c1ca EB |
48 | private final HTNode fNodeCache[] = new HTNode[CACHE_SIZE]; |
49 | ||
a52fde77 AM |
50 | /** |
51 | * Standard constructor | |
3de60236 | 52 | * |
360f899e | 53 | * @param config |
49a817d5 | 54 | * The configuration object for the StateHistoryTree |
ab604305 | 55 | * @param newFile |
360f899e | 56 | * Flag indicating that the file must be created from scratch |
49a817d5 | 57 | * |
a52fde77 | 58 | * @throws IOException |
360f899e | 59 | * An exception can be thrown when file cannot be accessed |
a52fde77 | 60 | */ |
8d47cc34 | 61 | public HT_IO(HTConfig config, boolean newFile) throws IOException { |
360f899e | 62 | fConfig = config; |
a52fde77 | 63 | |
360f899e | 64 | File historyTreeFile = config.getStateFile(); |
a52fde77 | 65 | if (newFile) { |
360f899e | 66 | boolean success1 = true; |
a52fde77 AM |
67 | /* Create a new empty History Tree file */ |
68 | if (historyTreeFile.exists()) { | |
ab604305 AM |
69 | success1 = historyTreeFile.delete(); |
70 | } | |
cb42195c | 71 | boolean success2 = historyTreeFile.createNewFile(); |
ab604305 AM |
72 | if (!(success1 && success2)) { |
73 | /* It seems we do not have permission to create the new file */ | |
74 | throw new IOException("Cannot create new file at " + //$NON-NLS-1$ | |
75 | historyTreeFile.getName()); | |
a52fde77 | 76 | } |
a52fde77 AM |
77 | fis = new FileInputStream(historyTreeFile); |
78 | fos = new FileOutputStream(historyTreeFile, false); | |
79 | } else { | |
80 | /* | |
81 | * We want to open an existing file, make sure we don't squash the | |
82 | * existing content when opening the fos! | |
83 | */ | |
84 | this.fis = new FileInputStream(historyTreeFile); | |
85 | this.fos = new FileOutputStream(historyTreeFile, true); | |
86 | } | |
87 | this.fcIn = fis.getChannel(); | |
88 | this.fcOut = fos.getChannel(); | |
89 | } | |
90 | ||
a52fde77 | 91 | /** |
8d47cc34 | 92 | * Read a node from the file on disk. |
3b7f5abe | 93 | * |
8d47cc34 AM |
94 | * @param seqNumber |
95 | * The sequence number of the node to read. | |
96 | * @return The object representing the node | |
3b7f5abe AM |
97 | * @throws ClosedChannelException |
98 | * Usually happens because the file was closed while we were | |
99 | * reading. Instead of using a big reader-writer lock, we'll | |
100 | * just catch this exception. | |
a52fde77 | 101 | */ |
8d47cc34 | 102 | public synchronized HTNode readNode(int seqNumber) throws ClosedChannelException { |
6993c1ca EB |
103 | /* Do a cache lookup */ |
104 | int offset = seqNumber & (CACHE_SIZE - 1); | |
105 | HTNode readNode = fNodeCache[offset]; | |
106 | if (readNode != null && readNode.getSequenceNumber() == seqNumber) { | |
49a817d5 | 107 | return readNode; |
6993c1ca EB |
108 | } |
109 | ||
110 | /* Lookup on disk */ | |
a52fde77 AM |
111 | try { |
112 | seekFCToNodePos(fcIn, seqNumber); | |
360f899e | 113 | readNode = HTNode.readNode(fConfig, fcIn); |
6993c1ca EB |
114 | |
115 | /* Put the node in the cache. */ | |
116 | fNodeCache[offset] = readNode; | |
a52fde77 | 117 | return readNode; |
3b7f5abe AM |
118 | } catch (ClosedChannelException e) { |
119 | throw e; | |
a52fde77 | 120 | } catch (IOException e) { |
3b7f5abe | 121 | /* Other types of IOExceptions shouldn't happen at this point though */ |
49a817d5 | 122 | Activator.getDefault().logError(e.getMessage(), e); |
a52fde77 AM |
123 | return null; |
124 | } | |
125 | } | |
126 | ||
e8b7cc14 | 127 | public synchronized void writeNode(HTNode node) { |
a52fde77 | 128 | try { |
6993c1ca EB |
129 | /* Insert the node into the cache. */ |
130 | int seqNumber = node.getSequenceNumber(); | |
131 | int offset = seqNumber & (CACHE_SIZE - 1); | |
132 | fNodeCache[offset] = node; | |
133 | ||
a52fde77 | 134 | /* Position ourselves at the start of the node and write it */ |
6993c1ca | 135 | seekFCToNodePos(fcOut, seqNumber); |
a52fde77 AM |
136 | node.writeSelf(fcOut); |
137 | } catch (IOException e) { | |
138 | /* If we were able to open the file, we should be fine now... */ | |
49a817d5 | 139 | Activator.getDefault().logError(e.getMessage(), e); |
a52fde77 AM |
140 | } |
141 | } | |
142 | ||
e8b7cc14 | 143 | public FileChannel getFcOut() { |
a52fde77 AM |
144 | return this.fcOut; |
145 | } | |
146 | ||
8d47cc34 | 147 | public FileInputStream supplyATReader(int nodeOffset) { |
a52fde77 AM |
148 | try { |
149 | /* | |
150 | * Position ourselves at the start of the Mapping section in the | |
151 | * file (which is right after the Blocks) | |
152 | */ | |
360f899e | 153 | seekFCToNodePos(fcIn, nodeOffset); |
a52fde77 | 154 | } catch (IOException e) { |
49a817d5 | 155 | Activator.getDefault().logError(e.getMessage(), e); |
a52fde77 AM |
156 | } |
157 | return fis; | |
158 | } | |
159 | ||
8d47cc34 | 160 | public synchronized void closeFile() { |
3de60236 AM |
161 | try { |
162 | fis.close(); | |
163 | fos.close(); | |
164 | } catch (IOException e) { | |
49a817d5 | 165 | Activator.getDefault().logError(e.getMessage(), e); |
3de60236 | 166 | } |
1a4205d9 AM |
167 | } |
168 | ||
8d47cc34 | 169 | public synchronized void deleteFile() { |
1a4205d9 | 170 | closeFile(); |
3de60236 | 171 | |
360f899e | 172 | File historyTreeFile = fConfig.getStateFile(); |
6993c1ca | 173 | if (!historyTreeFile.delete()) { |
36bf82a2 | 174 | /* We didn't succeed in deleting the file */ |
49a817d5 | 175 | Activator.getDefault().logError("Failed to delete" + historyTreeFile.getName()); //$NON-NLS-1$ |
36bf82a2 AM |
176 | } |
177 | } | |
178 | ||
a52fde77 AM |
179 | /** |
180 | * Seek the given FileChannel to the position corresponding to the node that | |
181 | * has seqNumber | |
3de60236 | 182 | * |
49a817d5 MK |
183 | * @param fc |
184 | * the channel to seek | |
185 | * @param seqNumber | |
186 | * the node sequence number to seek the channel to | |
a52fde77 | 187 | * @throws IOException |
49a817d5 | 188 | * If some other I/O error occurs |
a52fde77 AM |
189 | */ |
190 | private void seekFCToNodePos(FileChannel fc, int seqNumber) | |
191 | throws IOException { | |
a52fde77 | 192 | /* |
360f899e | 193 | * Cast to (long) is needed to make sure the result is a long too and |
a52fde77 AM |
194 | * doesn't get truncated |
195 | */ | |
360f899e | 196 | fc.position(HistoryTree.TREE_HEADER_SIZE |
49a817d5 | 197 | + ((long) seqNumber) * fConfig.getBlockSize()); |
a52fde77 AM |
198 | } |
199 | ||
200 | } |