| 1 | // Jomic - a viewer for comic book archives. |
| 2 | // Copyright (C) 2004-2011 Thomas Aglassinger |
| 3 | // |
| 4 | // This program is free software: you can redistribute it and/or modify |
| 5 | // it under the terms of the GNU General Public License as published by |
| 6 | // the Free Software Foundation, either version 3 of the License, or |
| 7 | // (at your option) any later version. |
| 8 | // |
| 9 | // This program is distributed in the hope that it will be useful, |
| 10 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | // GNU General Public License for more details. |
| 13 | // |
| 14 | // You should have received a copy of the GNU General Public License |
| 15 | // along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 16 | package net.sf.jomic.tools; |
| 17 | |
| 18 | import java.io.File; |
| 19 | |
| 20 | /** |
| 21 | * An entry in the cache. |
| 22 | * |
| 23 | * @author Thomas Aglassinger. |
| 24 | */ |
| 25 | public class ArchiveCacheEntry |
| 26 | { |
| 27 | /** |
| 28 | * Digits used to map the cache entry index to a sub directory name. The "long" directory is |
| 29 | * split in smaller subdirectories in order to prevent the cache main directory being |
| 30 | * cluttered with a sub directory for each cache entry. |
| 31 | */ |
| 32 | private static final int CACHE_DIR_DIGIT_COUNT = 8; |
| 33 | |
| 34 | /** |
| 35 | * Digits used to map the cache entry index to a directory name. |
| 36 | */ |
| 37 | private static final int CACHE_SUB_DIR_DIGIT_COUNT = 2; |
| 38 | |
| 39 | private File archiveFile; |
| 40 | private String cachedDir; |
| 41 | private int index; |
| 42 | private /*@ spec_public @*/ long lastAccessed; |
| 43 | private /*@ spec_public @*/ long lastModified; |
| 44 | private /*@ spec_public @*/ int lockCount; |
| 45 | private MutexLock lockMutex; |
| 46 | private /*@ spec_public @*/ long size; |
| 47 | |
| 48 | //@ invariant getArchiveFile() != null; |
| 49 | //@ invariant getCachedDirName() != null; |
| 50 | //@ invariant getIndex() >= 0; |
| 51 | //@ invariant getLockCount() >= 0; |
| 52 | //@ invariant getSize() >= 0; |
| 53 | |
| 54 | public ArchiveCacheEntry(File newArchiveFile, int newIndex) { |
| 55 | this(newArchiveFile, 0, 0, newIndex); |
| 56 | assert CACHE_DIR_DIGIT_COUNT % CACHE_SUB_DIR_DIGIT_COUNT == 0; |
| 57 | lastModified = newArchiveFile.lastModified(); |
| 58 | } |
| 59 | |
| 60 | public ArchiveCacheEntry(File newArchiveFile, long newLastAccessed, long newLastModified, int newIndex) { |
| 61 | StringTools stringTools = StringTools.instance(); |
| 62 | |
| 63 | archiveFile = newArchiveFile; |
| 64 | lastAccessed = newLastAccessed; |
| 65 | lastModified = newLastModified; |
| 66 | index = newIndex; |
| 67 | cachedDir = ""; |
| 68 | lockMutex = new MutexLock("ArchiveCacheEntry"); |
| 69 | |
| 70 | String indexText = stringTools.hexString(index, CACHE_DIR_DIGIT_COUNT, ""); |
| 71 | String separator = System.getProperty("file.separator"); |
| 72 | |
| 73 | for (int i = 0; i < indexText.length(); i += CACHE_SUB_DIR_DIGIT_COUNT) { |
| 74 | String pathPart = indexText.substring(i, i + CACHE_SUB_DIR_DIGIT_COUNT); |
| 75 | |
| 76 | if (cachedDir.length() > 0) { |
| 77 | cachedDir += separator; |
| 78 | } |
| 79 | cachedDir += pathPart; |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * Set the size used by all files stored in the cached directory relative to <code>baseDir</code> |
| 85 | * . |
| 86 | * |
| 87 | * @see ArchiveCache#setCacheEntrySize(ArchiveCacheEntry) |
| 88 | */ |
| 89 | //@ assignable size; |
| 90 | void setSize(File baseDir) { |
| 91 | FileTools fileTools = FileTools.instance(); |
| 92 | File dir = new File(baseDir, getCachedDirName()); |
| 93 | |
| 94 | size = fileTools.getSize(dir); |
| 95 | } |
| 96 | |
| 97 | /** |
| 98 | * Get the archive file from which the cache was extracted. |
| 99 | */ |
| 100 | public /*@ pure @*/ File getArchiveFile() { |
| 101 | return archiveFile; |
| 102 | } |
| 103 | |
| 104 | /** |
| 105 | * Get directory in <code>baseDir</code> where the files extracted from the archive are |
| 106 | * located. |
| 107 | */ |
| 108 | public /*@ pure @*/ File getCachedDir(File baseDir) { |
| 109 | assert baseDir != null; |
| 110 | return new File(baseDir, getCachedDirName()); |
| 111 | } |
| 112 | |
| 113 | /** |
| 114 | * Get relative directory name where the files extracted from the archive are located. |
| 115 | */ |
| 116 | public /*@ pure @*/ String getCachedDirName() { |
| 117 | return cachedDir; |
| 118 | } |
| 119 | |
| 120 | /** |
| 121 | * Get the index in the list of cached archives used to lookup the archive path. |
| 122 | */ |
| 123 | public /*@ pure @*/ int getIndex() { |
| 124 | return index; |
| 125 | } |
| 126 | |
| 127 | /** |
| 128 | * Get the timestamp when the cache was last accessed. |
| 129 | */ |
| 130 | public /*@ pure @*/ long getLastAccessed() { |
| 131 | return lastAccessed; |
| 132 | } |
| 133 | |
| 134 | /** |
| 135 | * Get the timestamp when the archive was cached. |
| 136 | */ |
| 137 | public /*@ pure @*/ long getLastModified() { |
| 138 | return lastModified; |
| 139 | } |
| 140 | |
| 141 | /** |
| 142 | * Number of clients that locked this entry to prevent it from being removed. |
| 143 | */ |
| 144 | public /*@ pure @*/ int getLockCount() { |
| 145 | return lockCount; |
| 146 | } |
| 147 | |
| 148 | /** |
| 149 | * Get the number of bytes used by all files in the archive. This is not the size it uses on |
| 150 | * the storage device though because this would depend on the block size of the device. |
| 151 | */ |
| 152 | public /*@ pure @*/ long getSize() { |
| 153 | return size; |
| 154 | } |
| 155 | |
| 156 | //@ assignable lockCount; |
| 157 | //@ ensures getLockCount() == \old(getLockCount()) + 1; |
| 158 | public void lock() { |
| 159 | synchronized (lockMutex) { |
| 160 | assert lockCount >= 0; |
| 161 | lockCount += 1; |
| 162 | } |
| 163 | } |
| 164 | |
| 165 | //@ requires getLockCount() > 0; |
| 166 | //@ assignable lockCount; |
| 167 | //@ ensures getLockCount() == \old(getLockCount()) - 1; |
| 168 | public void unlock() { |
| 169 | synchronized (lockMutex) { |
| 170 | assert lockCount > 0; |
| 171 | lockCount -= 1; |
| 172 | } |
| 173 | } |
| 174 | |
| 175 | //@ assignable lastAccessed; |
| 176 | void updateLastAccessed() { |
| 177 | lastAccessed = System.currentTimeMillis(); |
| 178 | } |
| 179 | |
| 180 | //@ assignable lastModified; |
| 181 | void updateLastModified() { |
| 182 | lastModified = System.currentTimeMillis(); |
| 183 | } |
| 184 | } |