--- /dev/null
+package be.nikiroo.utils;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.util.Date;
+
+import be.nikiroo.utils.streams.MarkableFileInputStream;
+
+/**
+ * A generic cache system, with special support for {@link URL}s.
+ * <p>
+ * This cache also manages timeout information.
+ *
+ * @author niki
+ */
+public class Cache {
+ private File dir;
+ private long tooOldChanging;
+ private long tooOldStable;
+ private TraceHandler tracer = new TraceHandler();
+
+ /**
+ * Only for inheritance.
+ */
+ protected Cache() {
+ }
+
+ /**
+ * Create a new {@link Cache} object.
+ *
+ * @param dir
+ * the directory to use as cache
+ * @param hoursChanging
+ * the number of hours after which a cached file that is thought
+ * to change ~often is considered too old (or -1 for
+ * "never too old")
+ * @param hoursStable
+ * the number of hours after which a cached file that is thought
+ * to change rarely is considered too old (or -1 for
+ * "never too old")
+ *
+ * @throws IOException
+ * in case of I/O error
+ */
+ public Cache(File dir, int hoursChanging, int hoursStable)
+ throws IOException {
+ this.dir = dir;
+ this.tooOldChanging = 1000L * 60 * 60 * hoursChanging;
+ this.tooOldStable = 1000L * 60 * 60 * hoursStable;
+
+ if (dir != null && !dir.exists()) {
+ dir.mkdirs();
+ }
+
+ if (dir == null || !dir.exists()) {
+ throw new IOException("Cannot create the cache directory: "
+ + (dir == null ? "null" : dir.getAbsolutePath()));
+ }
+ }
+
+ /**
+ * The traces handler for this {@link Cache}.
+ *
+ * @return the traces handler
+ */
+ public TraceHandler getTraceHandler() {
+ return tracer;
+ }
+
+ /**
+ * The traces handler for this {@link Cache}.
+ *
+ * @param tracer
+ * the new traces handler
+ */
+ public void setTraceHandler(TraceHandler tracer) {
+ if (tracer == null) {
+ tracer = new TraceHandler(false, false, false);
+ }
+
+ this.tracer = tracer;
+ }
+
+ /**
+ * Check the resource to see if it is in the cache.
+ *
+ * @param uniqueID
+ * the resource to check
+ * @param allowTooOld
+ * allow files even if they are considered too old
+ * @param stable
+ * a stable file (that dones't change too often) -- parameter
+ * used to check if the file is too old to keep or not
+ *
+ * @return TRUE if it is
+ *
+ */
+ public boolean check(String uniqueID, boolean allowTooOld, boolean stable) {
+ return check(getCached(uniqueID), allowTooOld, stable);
+ }
+
+ /**
+ * Check the resource to see if it is in the cache.
+ *
+ * @param url
+ * the resource to check
+ * @param allowTooOld
+ * allow files even if they are considered too old
+ * @param stable
+ * a stable file (that dones't change too often) -- parameter
+ * used to check if the file is too old to keep or not
+ *
+ * @return TRUE if it is
+ *
+ */
+ public boolean check(URL url, boolean allowTooOld, boolean stable) {
+ return check(getCached(url), allowTooOld, stable);
+ }
+
+ /**
+ * Check the resource to see if it is in the cache.
+ *
+ * @param cached
+ * the resource to check
+ * @param allowTooOld
+ * allow files even if they are considered too old
+ * @param stable
+ * a stable file (that dones't change too often) -- parameter
+ * used to check if the file is too old to keep or not
+ *
+ * @return TRUE if it is
+ *
+ */
+ private boolean check(File cached, boolean allowTooOld, boolean stable) {
+ if (cached.exists() && cached.isFile()) {
+ if (!allowTooOld && isOld(cached, stable)) {
+ if (!cached.delete()) {
+ tracer.error("Cannot delete temporary file: "
+ + cached.getAbsolutePath());
+ }
+ } else {
+ return true;
+ }
+ }
+
+ return false;
+ }
+
+ /**
+ * Clean the cache (delete the cached items).
+ *
+ * @param onlyOld
+ * only clean the files that are considered too old for a stable
+ * resource
+ *
+ * @return the number of cleaned items
+ */
+ public int clean(boolean onlyOld) {
+ long ms = System.currentTimeMillis();
+
+ tracer.trace("Cleaning cache from old files...");
+
+ int num = clean(onlyOld, dir, -1);
+
+ tracer.trace(num + "cache items cleaned in "
+ + (System.currentTimeMillis() - ms) + " ms");
+
+ return num;
+ }
+
+ /**
+ * Clean the cache (delete the cached items) in the given cache directory.
+ *
+ * @param onlyOld
+ * only clean the files that are considered too old for stable
+ * resources
+ * @param cacheDir
+ * the cache directory to clean
+ * @param limit
+ * stop after limit files deleted, or -1 for unlimited
+ *
+ * @return the number of cleaned items
+ */
+ private int clean(boolean onlyOld, File cacheDir, int limit) {
+ int num = 0;
+ File[] files = cacheDir.listFiles();
+ if (files != null) {
+ for (File file : files) {
+ if (limit >= 0 && num >= limit) {
+ return num;
+ }
+
+ if (file.isDirectory()) {
+ num += clean(onlyOld, file, limit);
+ file.delete(); // only if empty
+ } else {
+ if (!onlyOld || isOld(file, true)) {
+ if (file.delete()) {
+ num++;
+ } else {
+ tracer.error("Cannot delete temporary file: "
+ + file.getAbsolutePath());
+ }
+ }
+ }
+ }
+ }
+
+ return num;
+ }
+
+ /**
+ * Open a resource from the cache if it exists.
+ *
+ * @param uniqueID
+ * the unique ID
+ * @param allowTooOld
+ * allow files even if they are considered too old
+ * @param stable
+ * a stable file (that dones't change too often) -- parameter
+ * used to check if the file is too old to keep or not
+ *
+ * @return the opened resource if found, NULL if not
+ */
+ public InputStream load(String uniqueID, boolean allowTooOld, boolean stable) {
+ return load(getCached(uniqueID), allowTooOld, stable);
+ }
+
+ /**
+ * Open a resource from the cache if it exists.
+ *
+ * @param url
+ * the resource to open
+ * @param allowTooOld
+ * allow files even if they are considered too old
+ * @param stable
+ * a stable file (that doesn't change too often) -- parameter
+ * used to check if the file is too old to keep or not in the
+ * cache
+ *
+ * @return the opened resource if found, NULL if not
+ */
+ public InputStream load(URL url, boolean allowTooOld, boolean stable) {
+ return load(getCached(url), allowTooOld, stable);
+ }
+
+ /**
+ * Open a resource from the cache if it exists.
+ *
+ * @param cached
+ * the resource to open
+ * @param allowTooOld
+ * allow files even if they are considered too old
+ * @param stable
+ * a stable file (that dones't change too often) -- parameter
+ * used to check if the file is too old to keep or not
+ *
+ * @return the opened resource if found, NULL if not
+ */
+ private InputStream load(File cached, boolean allowTooOld, boolean stable) {
+ if (cached.exists() && cached.isFile()
+ && (allowTooOld || !isOld(cached, stable))) {
+ try {
+ return new MarkableFileInputStream(cached);
+ } catch (FileNotFoundException e) {
+ return null;
+ }
+ }
+
+ return null;
+ }
+
+ /**
+ * Save the given resource to the cache.
+ *
+ * @param in
+ * the input data
+ * @param uniqueID
+ * a unique ID used to locate the cached resource
+ *
+ * @return the number of bytes written
+ *
+ * @throws IOException
+ * in case of I/O error
+ */
+ public long save(InputStream in, String uniqueID) throws IOException {
+ File cached = getCached(uniqueID);
+ cached.getParentFile().mkdirs();
+ return save(in, cached);
+ }
+
+ /**
+ * Save the given resource to the cache.
+ *
+ * @param in
+ * the input data
+ * @param url
+ * the {@link URL} used to locate the cached resource
+ *
+ * @return the number of bytes written
+ *
+ * @throws IOException
+ * in case of I/O error
+ */
+ public long save(InputStream in, URL url) throws IOException {
+ File cached = getCached(url);
+ return save(in, cached);
+ }
+
+ /**
+ * Save the given resource to the cache.
+ * <p>
+ * Will also clean the {@link Cache} from old files.
+ *
+ * @param in
+ * the input data
+ * @param cached
+ * the cached {@link File} to save to
+ *
+ * @return the number of bytes written
+ *
+ * @throws IOException
+ * in case of I/O error
+ */
+ private long save(InputStream in, File cached) throws IOException {
+ // We want to force at least an immediate SAVE/LOAD to work for some
+ // workflows, even if we don't accept cached files (times set to "0"
+ // -- and not "-1" or a positive value)
+ clean(true, dir, 10);
+ cached.getParentFile().mkdirs(); // in case we deleted our own parent
+ long bytes = IOUtils.write(in, cached);
+ return bytes;
+ }
+
+ /**
+ * Remove the given resource from the cache.
+ *
+ * @param uniqueID
+ * a unique ID used to locate the cached resource
+ *
+ * @return TRUE if it was removed
+ */
+ public boolean remove(String uniqueID) {
+ File cached = getCached(uniqueID);
+ return cached.delete();
+ }
+
+ /**
+ * Remove the given resource from the cache.
+ *
+ * @param url
+ * the {@link URL} used to locate the cached resource
+ *
+ * @return TRUE if it was removed
+ */
+ public boolean remove(URL url) {
+ File cached = getCached(url);
+ return cached.delete();
+ }
+
+ /**
+ * Check if the {@link File} is too old according to
+ * {@link Cache#tooOldChanging}.
+ *
+ * @param file
+ * the file to check
+ * @param stable
+ * TRUE to denote stable files, that are not supposed to change
+ * too often
+ *
+ * @return TRUE if it is
+ */
+ private boolean isOld(File file, boolean stable) {
+ long max = tooOldChanging;
+ if (stable) {
+ max = tooOldStable;
+ }
+
+ if (max < 0) {
+ return false;
+ }
+
+ long time = new Date().getTime() - file.lastModified();
+ if (time < 0) {
+ tracer.error("Timestamp in the future for file: "
+ + file.getAbsolutePath());
+ }
+
+ return time < 0 || time > max;
+ }
+
+ /**
+ * Return the associated cache {@link File} from this {@link URL}.
+ *
+ * @param url
+ * the {@link URL}
+ *
+ * @return the cached {@link File} version of this {@link URL}
+ */
+ private File getCached(URL url) {
+ File subdir;
+
+ String name = url.getHost();
+ if (name == null || name.isEmpty()) {
+ // File
+ File file = new File(url.getFile());
+ if (file.getParent() == null) {
+ subdir = new File("+");
+ } else {
+ subdir = new File(file.getParent().replace("..", "__"));
+ }
+ subdir = new File(dir, allowedChars(subdir.getPath()));
+ name = allowedChars(url.getFile());
+ } else {
+ // URL
+ File subsubDir = new File(dir, allowedChars(url.getHost()));
+ subdir = new File(subsubDir, "_" + allowedChars(url.getPath()));
+ name = allowedChars("_" + url.getQuery());
+ }
+
+ File cacheFile = new File(subdir, name);
+ subdir.mkdirs();
+
+ return cacheFile;
+ }
+
+ /**
+ * Get the basic cache resource file corresponding to this unique ID.
+ * <p>
+ * Note that you may need to add a sub-directory in some cases.
+ *
+ * @param uniqueID
+ * the id
+ *
+ * @return the cached version if present, NULL if not
+ */
+ private File getCached(String uniqueID) {
+ File file = new File(dir, allowedChars(uniqueID));
+ File subdir = new File(file.getParentFile(), "_");
+ return new File(subdir, file.getName());
+ }
+
+ /**
+ * Replace not allowed chars (in a {@link File}) by "_".
+ *
+ * @param raw
+ * the raw {@link String}
+ *
+ * @return the sanitised {@link String}
+ */
+ private String allowedChars(String raw) {
+ return raw.replace('/', '_').replace(':', '_').replace("\\", "_");
+ }
+}
\ No newline at end of file
git://git.nikiroo.be / fanfix.git / blobdiff