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a52fde77 | 1 | /******************************************************************************* |
60ae41e1 | 2 | * Copyright (c) 2012, 2014 Ericsson |
a52fde77 AM |
3 | * Copyright (c) 2010, 2011 École Polytechnique de Montréal |
4 | * Copyright (c) 2010, 2011 Alexandre Montplaisir <alexandre.montplaisir@gmail.com> | |
3de60236 | 5 | * |
a52fde77 AM |
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 | * |
a52fde77 AM |
11 | *******************************************************************************/ |
12 | ||
e894a508 | 13 | package org.eclipse.tracecompass.internal.statesystem.core.backend.historytree; |
a52fde77 AM |
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; |
a52fde77 AM |
20 | import java.nio.channels.FileChannel; |
21 | ||
aa353506 | 22 | import org.eclipse.jdt.annotation.NonNull; |
4018d70a | 23 | import org.eclipse.jdt.annotation.NonNullByDefault; |
49a817d5 MK |
24 | import org.eclipse.tracecompass.internal.statesystem.core.Activator; |
25 | ||
a52fde77 | 26 | /** |
360f899e EB |
27 | * This class abstracts inputs/outputs of the HistoryTree nodes. |
28 | * | |
29 | * It contains all the methods and descriptors to handle reading/writing nodes | |
30 | * to the tree-file on disk and all the caching mechanisms. | |
31 | * | |
49a817d5 MK |
32 | * This abstraction is mainly for code isolation/clarification purposes. Every |
33 | * HistoryTree must contain 1 and only 1 HT_IO element. | |
3de60236 | 34 | * |
ffd0aa67 | 35 | * @author Alexandre Montplaisir |
3de60236 | 36 | * |
a52fde77 AM |
37 | */ |
38 | class HT_IO { | |
4018d70a MK |
39 | |
40 | @NonNullByDefault | |
41 | private static final class CacheElement { | |
42 | private final HTNode value; | |
43 | private final HT_IO key; | |
44 | ||
45 | public CacheElement(HT_IO ss, HTNode node) { | |
46 | key = ss; | |
47 | value = node; | |
48 | } | |
49 | ||
50 | public HT_IO getKey() { | |
51 | return key; | |
52 | } | |
53 | ||
54 | public HTNode getValue() { | |
55 | return value; | |
56 | } | |
57 | } | |
58 | ||
360f899e EB |
59 | /* Configuration of the History Tree */ |
60 | private final HTConfig fConfig; | |
a52fde77 AM |
61 | |
62 | /* Fields related to the file I/O */ | |
c772ff74 MK |
63 | private final FileInputStream fFileInputStream; |
64 | private final FileOutputStream fFileOutputStream; | |
65 | private final FileChannel fFileChannelIn; | |
66 | private final FileChannel fFileChannelOut; | |
a52fde77 | 67 | |
0c1d4577 | 68 | // TODO test/benchmark optimal cache size |
c772ff74 MK |
69 | /** |
70 | * Cache size, must be a power of 2 | |
71 | */ | |
49a817d5 | 72 | private static final int CACHE_SIZE = 256; |
c772ff74 | 73 | private static final int CACHE_MASK = CACHE_SIZE - 1; |
4018d70a | 74 | private static final CacheElement NODE_CACHE[] = new CacheElement[CACHE_SIZE]; |
6993c1ca | 75 | |
a52fde77 AM |
76 | /** |
77 | * Standard constructor | |
3de60236 | 78 | * |
360f899e | 79 | * @param config |
49a817d5 | 80 | * The configuration object for the StateHistoryTree |
ab604305 | 81 | * @param newFile |
360f899e | 82 | * Flag indicating that the file must be created from scratch |
49a817d5 | 83 | * |
a52fde77 | 84 | * @throws IOException |
360f899e | 85 | * An exception can be thrown when file cannot be accessed |
a52fde77 | 86 | */ |
8d47cc34 | 87 | public HT_IO(HTConfig config, boolean newFile) throws IOException { |
360f899e | 88 | fConfig = config; |
a52fde77 | 89 | |
360f899e | 90 | File historyTreeFile = config.getStateFile(); |
a52fde77 | 91 | if (newFile) { |
360f899e | 92 | boolean success1 = true; |
a52fde77 AM |
93 | /* Create a new empty History Tree file */ |
94 | if (historyTreeFile.exists()) { | |
ab604305 AM |
95 | success1 = historyTreeFile.delete(); |
96 | } | |
cb42195c | 97 | boolean success2 = historyTreeFile.createNewFile(); |
ab604305 AM |
98 | if (!(success1 && success2)) { |
99 | /* It seems we do not have permission to create the new file */ | |
100 | throw new IOException("Cannot create new file at " + //$NON-NLS-1$ | |
101 | historyTreeFile.getName()); | |
a52fde77 | 102 | } |
c772ff74 MK |
103 | fFileInputStream = new FileInputStream(historyTreeFile); |
104 | fFileOutputStream = new FileOutputStream(historyTreeFile, false); | |
a52fde77 AM |
105 | } else { |
106 | /* | |
107 | * We want to open an existing file, make sure we don't squash the | |
108 | * existing content when opening the fos! | |
109 | */ | |
c772ff74 MK |
110 | fFileInputStream = new FileInputStream(historyTreeFile); |
111 | fFileOutputStream = new FileOutputStream(historyTreeFile, true); | |
a52fde77 | 112 | } |
c772ff74 MK |
113 | fFileChannelIn = fFileInputStream.getChannel(); |
114 | fFileChannelOut = fFileOutputStream.getChannel(); | |
a52fde77 AM |
115 | } |
116 | ||
a52fde77 | 117 | /** |
8d47cc34 | 118 | * Read a node from the file on disk. |
3b7f5abe | 119 | * |
8d47cc34 AM |
120 | * @param seqNumber |
121 | * The sequence number of the node to read. | |
122 | * @return The object representing the node | |
3b7f5abe AM |
123 | * @throws ClosedChannelException |
124 | * Usually happens because the file was closed while we were | |
125 | * reading. Instead of using a big reader-writer lock, we'll | |
126 | * just catch this exception. | |
a52fde77 | 127 | */ |
aa353506 | 128 | public synchronized @NonNull HTNode readNode(int seqNumber) throws ClosedChannelException { |
6993c1ca | 129 | /* Do a cache lookup */ |
4018d70a MK |
130 | int offset = (seqNumber + hashCode()) & CACHE_MASK; |
131 | CacheElement cachedNode = NODE_CACHE[offset]; | |
132 | ||
133 | if (cachedNode != null && cachedNode.getKey() == this && cachedNode.getValue().getSequenceNumber() == seqNumber) { | |
134 | return cachedNode.getValue(); | |
6993c1ca EB |
135 | } |
136 | ||
137 | /* Lookup on disk */ | |
a52fde77 | 138 | try { |
c772ff74 | 139 | seekFCToNodePos(fFileChannelIn, seqNumber); |
4018d70a | 140 | HTNode readNode = HTNode.readNode(fConfig, fFileChannelIn); |
6993c1ca EB |
141 | |
142 | /* Put the node in the cache. */ | |
4018d70a | 143 | NODE_CACHE[offset] = new CacheElement(this, readNode); |
a52fde77 | 144 | return readNode; |
aa353506 | 145 | |
3b7f5abe AM |
146 | } catch (ClosedChannelException e) { |
147 | throw e; | |
a52fde77 | 148 | } catch (IOException e) { |
4018d70a MK |
149 | /* |
150 | * Other types of IOExceptions shouldn't happen at this point though | |
151 | */ | |
49a817d5 | 152 | Activator.getDefault().logError(e.getMessage(), e); |
aa353506 | 153 | throw new IllegalStateException(); |
a52fde77 AM |
154 | } |
155 | } | |
156 | ||
e8b7cc14 | 157 | public synchronized void writeNode(HTNode node) { |
a52fde77 | 158 | try { |
6993c1ca EB |
159 | /* Insert the node into the cache. */ |
160 | int seqNumber = node.getSequenceNumber(); | |
4018d70a MK |
161 | int offset = (seqNumber + hashCode()) & CACHE_MASK; |
162 | NODE_CACHE[offset] = new CacheElement(this, node); | |
6993c1ca | 163 | |
a52fde77 | 164 | /* Position ourselves at the start of the node and write it */ |
c772ff74 MK |
165 | seekFCToNodePos(fFileChannelOut, seqNumber); |
166 | node.writeSelf(fFileChannelOut); | |
a52fde77 AM |
167 | } catch (IOException e) { |
168 | /* If we were able to open the file, we should be fine now... */ | |
49a817d5 | 169 | Activator.getDefault().logError(e.getMessage(), e); |
a52fde77 AM |
170 | } |
171 | } | |
172 | ||
e8b7cc14 | 173 | public FileChannel getFcOut() { |
c772ff74 | 174 | return fFileChannelOut; |
a52fde77 AM |
175 | } |
176 | ||
8d47cc34 | 177 | public FileInputStream supplyATReader(int nodeOffset) { |
a52fde77 AM |
178 | try { |
179 | /* | |
180 | * Position ourselves at the start of the Mapping section in the | |
181 | * file (which is right after the Blocks) | |
182 | */ | |
c772ff74 | 183 | seekFCToNodePos(fFileChannelIn, nodeOffset); |
a52fde77 | 184 | } catch (IOException e) { |
49a817d5 | 185 | Activator.getDefault().logError(e.getMessage(), e); |
a52fde77 | 186 | } |
c772ff74 | 187 | return fFileInputStream; |
a52fde77 AM |
188 | } |
189 | ||
8d47cc34 | 190 | public synchronized void closeFile() { |
3de60236 | 191 | try { |
c772ff74 MK |
192 | fFileInputStream.close(); |
193 | fFileOutputStream.close(); | |
3de60236 | 194 | } catch (IOException e) { |
49a817d5 | 195 | Activator.getDefault().logError(e.getMessage(), e); |
3de60236 | 196 | } |
1a4205d9 AM |
197 | } |
198 | ||
8d47cc34 | 199 | public synchronized void deleteFile() { |
1a4205d9 | 200 | closeFile(); |
3de60236 | 201 | |
360f899e | 202 | File historyTreeFile = fConfig.getStateFile(); |
6993c1ca | 203 | if (!historyTreeFile.delete()) { |
36bf82a2 | 204 | /* We didn't succeed in deleting the file */ |
49a817d5 | 205 | Activator.getDefault().logError("Failed to delete" + historyTreeFile.getName()); //$NON-NLS-1$ |
36bf82a2 AM |
206 | } |
207 | } | |
208 | ||
a52fde77 AM |
209 | /** |
210 | * Seek the given FileChannel to the position corresponding to the node that | |
211 | * has seqNumber | |
3de60236 | 212 | * |
49a817d5 MK |
213 | * @param fc |
214 | * the channel to seek | |
215 | * @param seqNumber | |
216 | * the node sequence number to seek the channel to | |
a52fde77 | 217 | * @throws IOException |
49a817d5 | 218 | * If some other I/O error occurs |
a52fde77 AM |
219 | */ |
220 | private void seekFCToNodePos(FileChannel fc, int seqNumber) | |
221 | throws IOException { | |
a52fde77 | 222 | /* |
360f899e | 223 | * Cast to (long) is needed to make sure the result is a long too and |
a52fde77 AM |
224 | * doesn't get truncated |
225 | */ | |
360f899e | 226 | fc.position(HistoryTree.TREE_HEADER_SIZE |
49a817d5 | 227 | + ((long) seqNumber) * fConfig.getBlockSize()); |
a52fde77 AM |
228 | } |
229 | ||
230 | } |