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1 | package be.nikiroo.utils; |
2 | ||
3 | import java.io.File; | |
4 | import java.io.FileInputStream; | |
5 | import java.io.FileNotFoundException; | |
6 | import java.io.IOException; | |
7 | import java.io.InputStream; | |
8 | import java.net.URL; | |
9 | import java.util.Date; | |
10 | ||
11 | /** | |
12 | * A generic cache system, with special support for {@link URL}s. | |
13 | * <p> | |
14 | * This cache also manages timeout information. | |
15 | * | |
16 | * @author niki | |
17 | */ | |
18 | public class Cache { | |
19 | private File dir; | |
20 | private long tooOldChanging; | |
21 | private long tooOldStable; | |
530d4062 | 22 | private TraceHandler tracer = new TraceHandler(); |
8816d2f7 NR |
23 | |
24 | /** | |
25 | * Create a new {@link Cache} object. | |
26 | * | |
27 | * @param dir | |
28 | * the directory to use as cache | |
29 | * @param hoursChanging | |
30 | * the number of hours after which a cached file that is thought | |
31 | * to change ~often is considered too old (or -1 for | |
32 | * "never too old") | |
33 | * @param hoursStable | |
34 | * the number of hours after which a cached file that is thought | |
35 | * to change rarely is considered too old (or -1 for | |
36 | * "never too old") | |
37 | * | |
38 | * @throws IOException | |
39 | * in case of I/O error | |
40 | */ | |
41 | public Cache(File dir, int hoursChanging, int hoursStable) | |
42 | throws IOException { | |
43 | this.dir = dir; | |
44 | this.tooOldChanging = 1000 * 60 * 60 * hoursChanging; | |
45 | this.tooOldStable = 1000 * 60 * 60 * hoursStable; | |
46 | ||
47 | if (dir != null && !dir.exists()) { | |
48 | dir.mkdirs(); | |
49 | } | |
50 | ||
51 | if (dir == null || !dir.exists()) { | |
52 | throw new IOException("Cannot create the cache directory: " | |
53 | + (dir == null ? "null" : dir.getAbsolutePath())); | |
54 | } | |
55 | } | |
56 | ||
530d4062 NR |
57 | /** |
58 | * The traces handler for this {@link Cache}. | |
59 | * | |
60 | * @return the traces handler | |
61 | */ | |
62 | public TraceHandler getTraceHandler() { | |
63 | return tracer; | |
64 | } | |
65 | ||
66 | /** | |
67 | * The traces handler for this {@link Cache}. | |
68 | * | |
69 | * @param tracer | |
70 | * the new traces handler | |
71 | */ | |
72 | public void setTraceHandler(TraceHandler tracer) { | |
73 | this.tracer = tracer; | |
74 | } | |
75 | ||
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76 | /** |
77 | * Check the resource to see if it is in the cache. | |
78 | * | |
79 | * @param url | |
80 | * the resource to check | |
81 | * @param allowTooOld | |
82 | * allow files even if they are considered too old | |
83 | * @param stable | |
84 | * a stable file (that dones't change too often) -- parameter | |
85 | * used to check if the file is too old to keep or not | |
86 | * | |
87 | * @return TRUE if it is | |
88 | * | |
89 | */ | |
90 | public boolean check(URL url, boolean allowTooOld, boolean stable) { | |
91 | File file = getCached(url); | |
92 | if (file.exists()) { | |
93 | if (allowTooOld || !isOld(file, stable)) { | |
94 | return true; | |
95 | } | |
96 | } | |
97 | ||
98 | return false; | |
99 | } | |
100 | ||
101 | /** | |
102 | * Clean the cache (delete the cached items). | |
103 | * | |
104 | * @param onlyOld | |
105 | * only clean the files that are considered too old for a stable | |
106 | * resource | |
107 | * | |
108 | * @return the number of cleaned items | |
109 | */ | |
110 | public int clean(boolean onlyOld) { | |
111 | return clean(onlyOld, dir); | |
112 | } | |
113 | ||
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114 | /** |
115 | * Clean the cache (delete the cached items) in the given cache directory. | |
116 | * | |
117 | * @param onlyOld | |
118 | * only clean the files that are considered too old for stable | |
119 | * resources | |
120 | * @param cacheDir | |
121 | * the cache directory to clean | |
122 | * | |
123 | * @return the number of cleaned items | |
124 | */ | |
125 | private int clean(boolean onlyOld, File cacheDir) { | |
126 | int num = 0; | |
127 | for (File file : cacheDir.listFiles()) { | |
128 | if (file.isDirectory()) { | |
129 | num += clean(onlyOld, file); | |
130 | } else { | |
131 | if (!onlyOld || isOld(file, true)) { | |
132 | if (file.delete()) { | |
133 | num++; | |
134 | } else { | |
530d4062 NR |
135 | tracer.error("Cannot delete temporary file: " |
136 | + file.getAbsolutePath()); | |
8816d2f7 NR |
137 | } |
138 | } | |
139 | } | |
140 | } | |
141 | ||
142 | return num; | |
143 | } | |
144 | ||
145 | /** | |
146 | * Open a resource from the cache if it exists. | |
147 | * | |
148 | * @param uniqueID | |
149 | * the unique ID | |
150 | * @param allowTooOld | |
151 | * allow files even if they are considered too old | |
152 | * @param stable | |
153 | * a stable file (that dones't change too often) -- parameter | |
154 | * used to check if the file is too old to keep or not | |
155 | * | |
156 | * @return the opened resource if found, NULL if not | |
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157 | */ |
158 | public InputStream load(String uniqueID, boolean allowTooOld, boolean stable) { | |
159 | return load(getCached(uniqueID), allowTooOld, stable); | |
160 | } | |
161 | ||
162 | /** | |
163 | * Open a resource from the cache if it exists. | |
164 | * | |
165 | * @param url | |
166 | * the resource to open | |
167 | * @param allowTooOld | |
168 | * allow files even if they are considered too old | |
169 | * @param stable | |
170 | * a stable file (that dones't change too often) -- parameter | |
171 | * used to check if the file is too old to keep or not | |
172 | * | |
173 | * @return the opened resource if found, NULL if not | |
8816d2f7 | 174 | */ |
2ee6c205 | 175 | public InputStream load(URL url, boolean allowTooOld, boolean stable) { |
8816d2f7 NR |
176 | return load(getCached(url), allowTooOld, stable); |
177 | } | |
178 | ||
179 | /** | |
180 | * Open a resource from the cache if it exists. | |
181 | * | |
2ee6c205 | 182 | * @param cached |
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183 | * the resource to open |
184 | * @param allowTooOld | |
185 | * allow files even if they are considered too old | |
186 | * @param stable | |
187 | * a stable file (that dones't change too often) -- parameter | |
188 | * used to check if the file is too old to keep or not | |
189 | * | |
190 | * @return the opened resource if found, NULL if not | |
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191 | */ |
192 | private InputStream load(File cached, boolean allowTooOld, boolean stable) { | |
193 | if (cached.exists() && (allowTooOld || !isOld(cached, stable))) { | |
194 | try { | |
195 | return new MarkableFileInputStream(new FileInputStream(cached)); | |
196 | } catch (FileNotFoundException e) { | |
197 | return null; | |
198 | } | |
199 | } | |
200 | ||
201 | return null; | |
202 | } | |
203 | ||
204 | /** | |
205 | * Save the given resource to the cache. | |
206 | * | |
207 | * @param in | |
208 | * the input data | |
209 | * @param uniqueID | |
210 | * a unique ID used to locate the cached resource | |
211 | * | |
212 | * @return the resulting {@link File} | |
213 | * | |
214 | * @throws IOException | |
215 | * in case of I/O error | |
216 | */ | |
217 | public File save(InputStream in, String uniqueID) throws IOException { | |
218 | File cached = getCached(uniqueID); | |
219 | cached.getParentFile().mkdirs(); | |
220 | return save(in, cached); | |
221 | } | |
222 | ||
223 | /** | |
224 | * Save the given resource to the cache. | |
225 | * | |
226 | * @param in | |
227 | * the input data | |
228 | * @param url | |
229 | * the {@link URL} used to locate the cached resource | |
230 | * | |
2ee6c205 NR |
231 | * @return the actual cache file |
232 | * | |
8816d2f7 NR |
233 | * @throws IOException |
234 | * in case of I/O error | |
235 | */ | |
236 | public File save(InputStream in, URL url) throws IOException { | |
237 | File cached = getCached(url); | |
238 | return save(in, cached); | |
239 | } | |
240 | ||
241 | /** | |
242 | * Save the given resource to the cache. | |
243 | * | |
244 | * @param in | |
245 | * the input data | |
246 | * @param cached | |
247 | * the cached {@link File} to save to | |
248 | * | |
2ee6c205 NR |
249 | * @return the actual cache file |
250 | * | |
8816d2f7 NR |
251 | * @throws IOException |
252 | * in case of I/O error | |
253 | */ | |
254 | private File save(InputStream in, File cached) throws IOException { | |
255 | IOUtils.write(in, cached); | |
256 | return cached; | |
257 | } | |
258 | ||
2ee6c205 NR |
259 | /** |
260 | * Remove the given resource from the cache. | |
261 | * | |
262 | * @param uniqueID | |
263 | * a unique ID used to locate the cached resource | |
264 | * | |
265 | * @return TRUE if it was removed | |
266 | */ | |
267 | public boolean remove(String uniqueID) { | |
268 | File cached = getCached(uniqueID); | |
269 | return cached.delete(); | |
270 | } | |
271 | ||
272 | /** | |
273 | * Remove the given resource from the cache. | |
274 | * | |
275 | * @param url | |
276 | * the {@link URL} used to locate the cached resource | |
277 | * | |
278 | * @return TRUE if it was removed | |
279 | */ | |
280 | public boolean remove(URL url) { | |
281 | File cached = getCached(url); | |
282 | return cached.delete(); | |
283 | } | |
284 | ||
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285 | /** |
286 | * Check if the {@link File} is too old according to | |
287 | * {@link Cache#tooOldChanging}. | |
288 | * | |
289 | * @param file | |
290 | * the file to check | |
291 | * @param stable | |
292 | * TRUE to denote stable files, that are not supposed to change | |
293 | * too often | |
294 | * | |
295 | * @return TRUE if it is | |
296 | */ | |
297 | private boolean isOld(File file, boolean stable) { | |
298 | long max = tooOldChanging; | |
299 | if (stable) { | |
300 | max = tooOldStable; | |
301 | } | |
302 | ||
303 | if (max < 0) { | |
304 | return false; | |
305 | } | |
306 | ||
307 | long time = new Date().getTime() - file.lastModified(); | |
308 | if (time < 0) { | |
530d4062 NR |
309 | tracer.error("Timestamp in the future for file: " |
310 | + file.getAbsolutePath()); | |
8816d2f7 NR |
311 | } |
312 | ||
313 | return time < 0 || time > max; | |
314 | } | |
315 | ||
316 | /** | |
317 | * Return the associated cache {@link File} from this {@link URL}. | |
318 | * | |
319 | * @param url | |
320 | * the {@link URL} | |
321 | * | |
322 | * @return the cached {@link File} version of this {@link URL} | |
323 | */ | |
324 | private File getCached(URL url) { | |
325 | File subdir; | |
326 | ||
327 | String name = url.getHost(); | |
328 | if (name == null || name.isEmpty()) { | |
329 | // File | |
330 | File file = new File(url.getFile()); | |
331 | subdir = new File(file.getParent().replace("..", "__")); | |
332 | subdir = new File(dir, allowedChars(subdir.getPath())); | |
333 | name = allowedChars(url.getFile()); | |
334 | } else { | |
335 | // URL | |
336 | File subsubDir = new File(dir, allowedChars(url.getHost())); | |
337 | subdir = new File(subsubDir, "_" + allowedChars(url.getPath())); | |
338 | name = allowedChars("_" + url.getQuery()); | |
339 | } | |
340 | ||
341 | File cacheFile = new File(subdir, name); | |
342 | subdir.mkdirs(); | |
343 | ||
344 | return cacheFile; | |
345 | } | |
346 | ||
347 | /** | |
348 | * Get the basic cache resource file corresponding to this unique ID. | |
349 | * <p> | |
350 | * Note that you may need to add a sub-directory in some cases. | |
351 | * | |
352 | * @param uniqueID | |
353 | * the id | |
354 | * | |
355 | * @return the cached version if present, NULL if not | |
356 | */ | |
357 | private File getCached(String uniqueID) { | |
358 | File file = new File(dir, allowedChars(uniqueID)); | |
359 | File subdir = new File(file.getParentFile(), "_"); | |
360 | return new File(subdir, file.getName()); | |
361 | } | |
362 | ||
363 | /** | |
364 | * Replace not allowed chars (in a {@link File}) by "_". | |
365 | * | |
366 | * @param raw | |
367 | * the raw {@link String} | |
368 | * | |
369 | * @return the sanitised {@link String} | |
370 | */ | |
371 | private String allowedChars(String raw) { | |
372 | return raw.replace('/', '_').replace(':', '_').replace("\\", "_"); | |
373 | } | |
374 | } |