mirror of
https://gitlab.com/mangadex-pub/mangadex_at_home.git
synced 2024-01-19 02:48:37 +00:00
950 lines
28 KiB
Java
950 lines
28 KiB
Java
/*
|
|
* Copyright (C) 2011 The Android Open Source Project
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
package mdnet.cache;
|
|
|
|
import org.apache.commons.io.IOUtils;
|
|
import org.slf4j.Logger;
|
|
import org.slf4j.LoggerFactory;
|
|
|
|
import java.io.BufferedWriter;
|
|
import java.io.Closeable;
|
|
import java.io.EOFException;
|
|
import java.io.File;
|
|
import java.io.FileInputStream;
|
|
import java.io.FileNotFoundException;
|
|
import java.io.FileOutputStream;
|
|
import java.io.FilterOutputStream;
|
|
import java.io.IOException;
|
|
import java.io.InputStream;
|
|
import java.io.OutputStream;
|
|
import java.io.OutputStreamWriter;
|
|
import java.io.Writer;
|
|
import java.nio.charset.StandardCharsets;
|
|
import java.util.ArrayList;
|
|
import java.util.Iterator;
|
|
import java.util.LinkedHashMap;
|
|
import java.util.Map;
|
|
import java.util.concurrent.Callable;
|
|
import java.util.concurrent.LinkedBlockingQueue;
|
|
import java.util.concurrent.ThreadPoolExecutor;
|
|
import java.util.concurrent.TimeUnit;
|
|
import java.util.regex.Matcher;
|
|
import java.util.regex.Pattern;
|
|
|
|
/**
|
|
* A cache that uses a bounded amount of space on a filesystem. Each cache entry
|
|
* has a string key and a fixed number of values. Each key must match the regex
|
|
* <strong>[a-z0-9_-]{1,120}</strong>. Values are byte sequences, accessible as
|
|
* streams or files. Each value must be between {@code 0} and
|
|
* {@code Integer.MAX_VALUE} bytes in length.
|
|
*
|
|
* <p>
|
|
* The cache stores its data in a directory on the filesystem. This directory
|
|
* must be exclusive to the cache; the cache may delete or overwrite files from
|
|
* its directory. It is an error for multiple processes to use the same cache
|
|
* directory at the same time.
|
|
*
|
|
* <p>
|
|
* This cache limits the number of bytes that it will store on the filesystem.
|
|
* When the number of stored bytes exceeds the limit, the cache will remove
|
|
* entries in the background until the limit is satisfied. The limit is not
|
|
* strict: the cache may temporarily exceed it while waiting for files to be
|
|
* deleted. The limit does not include filesystem overhead or the cache journal
|
|
* so space-sensitive applications should set a conservative limit.
|
|
*
|
|
* <p>
|
|
* Clients call {@link #edit} to create or update the values of an entry. An
|
|
* entry may have only one editor at one time; if a value is not available to be
|
|
* edited then {@link #edit} will return null.
|
|
* <ul>
|
|
* <li>When an entry is being <strong>created</strong> it is necessary to supply
|
|
* a full set of values; the empty value should be used as a placeholder if
|
|
* necessary.
|
|
* <li>When an entry is being <strong>edited</strong>, it is not necessary to
|
|
* supply data for every value; values default to their previous value.
|
|
* </ul>
|
|
* Every {@link #edit} call must be matched by a call to {@link Editor#commit}
|
|
* or {@link Editor#abort}. Committing is atomic: a read observes the full set
|
|
* of values as they were before or after the commit, but never a mix of values.
|
|
*
|
|
* <p>
|
|
* Clients call {@link #get} to read a snapshot of an entry. The read will
|
|
* observe the value at the time that {@link #get} was called. Updates and
|
|
* removals after the call do not impact ongoing reads.
|
|
*
|
|
* <p>
|
|
* This class is tolerant of some I/O errors. If files are missing from the
|
|
* filesystem, the corresponding entries will be dropped from the cache. If an
|
|
* error occurs while writing a cache value, the edit will fail silently.
|
|
* Callers should handle other problems by catching {@code IOException} and
|
|
* responding appropriately.
|
|
*/
|
|
public final class DiskLruCache implements Closeable {
|
|
private final static Logger LOGGER = LoggerFactory.getLogger(DiskLruCache.class);
|
|
|
|
private static final String JOURNAL_FILE = "journal";
|
|
private static final String JOURNAL_FILE_TEMP = "journal.tmp";
|
|
private static final String JOURNAL_FILE_BACKUP = "journal.bkp";
|
|
|
|
private static final String MAGIC = "libcore.io.DiskLruCache";
|
|
private static final String VERSION_1 = "1";
|
|
private static final long ANY_SEQUENCE_NUMBER = -1;
|
|
private static final String STRING_KEY_PATTERN = "[a-z0-9_-]{1,120}";
|
|
public static final Pattern LEGAL_KEY_PATTERN = Pattern.compile(STRING_KEY_PATTERN);
|
|
private static final String CLEAN = "CLEAN";
|
|
private static final String DIRTY = "DIRTY";
|
|
private static final String REMOVE = "REMOVE";
|
|
private static final String READ = "READ";
|
|
|
|
/*
|
|
* This cache uses a journal file named "journal". A typical journal file looks
|
|
* like this: libcore.io.DiskLruCache 1 100 2
|
|
*
|
|
* CLEAN 3400330d1dfc7f3f7f4b8d4d803dfcf6 832 21054 DIRTY
|
|
* 335c4c6028171cfddfbaae1a9c313c52 CLEAN 335c4c6028171cfddfbaae1a9c313c52 3934
|
|
* 2342 REMOVE 335c4c6028171cfddfbaae1a9c313c52 DIRTY
|
|
* 1ab96a171faeeee38496d8b330771a7a CLEAN 1ab96a171faeeee38496d8b330771a7a 1600
|
|
* 234 READ 335c4c6028171cfddfbaae1a9c313c52 READ
|
|
* 3400330d1dfc7f3f7f4b8d4d803dfcf6
|
|
*
|
|
* The first five lines of the journal form its header. They are the constant
|
|
* string "libcore.io.DiskLruCache", the disk cache's version, the application's
|
|
* version, the value count, and a blank line.
|
|
*
|
|
* Each of the subsequent lines in the file is a record of the state of a cache
|
|
* entry. Each line contains space-separated values: a state, a key, and
|
|
* optional state-specific values. o DIRTY lines track that an entry is actively
|
|
* being created or updated. Every successful DIRTY action should be followed by
|
|
* a CLEAN or REMOVE action. DIRTY lines without a matching CLEAN or REMOVE
|
|
* indicate that temporary files may need to be deleted. o CLEAN lines track a
|
|
* cache entry that has been successfully published and may be read. A publish
|
|
* line is followed by the lengths of each of its values. o READ lines track
|
|
* accesses for LRU. o REMOVE lines track entries that have been deleted.
|
|
*
|
|
* The journal file is appended to as cache operations occur. The journal may
|
|
* occasionally be compacted by dropping redundant lines. A temporary file named
|
|
* "journal.tmp" will be used during compaction; that file should be deleted if
|
|
* it exists when the cache is opened.
|
|
*/
|
|
|
|
private final File directory;
|
|
private final File journalFile;
|
|
private final File journalFileTmp;
|
|
private final File journalFileBackup;
|
|
private final int appVersion;
|
|
private long maxSize;
|
|
private final int valueCount;
|
|
private long size = 0;
|
|
private Writer journalWriter;
|
|
private final LinkedHashMap<String, Entry> lruEntries = new LinkedHashMap<>(0, 0.75f, true);
|
|
private int redundantOpCount;
|
|
|
|
/**
|
|
* To differentiate between old and current snapshots, each entry is given a
|
|
* sequence number each time an edit is committed. A snapshot is stale if its
|
|
* sequence number is not equal to its entry's sequence number.
|
|
*/
|
|
private long nextSequenceNumber = 0;
|
|
|
|
/** This cache uses a single background thread to evict entries. */
|
|
final ThreadPoolExecutor executorService = new ThreadPoolExecutor(0, 1, 60L, TimeUnit.SECONDS,
|
|
new LinkedBlockingQueue<>());
|
|
private final Callable<Void> cleanupCallable = new Callable<Void>() {
|
|
public Void call() throws Exception {
|
|
synchronized (DiskLruCache.this) {
|
|
if (journalWriter == null) {
|
|
return null; // Closed.
|
|
}
|
|
trimToSize();
|
|
if (journalRebuildRequired()) {
|
|
rebuildJournal();
|
|
redundantOpCount = 0;
|
|
}
|
|
}
|
|
return null;
|
|
}
|
|
};
|
|
|
|
private DiskLruCache(File directory, int appVersion, int valueCount, long maxSize) {
|
|
this.directory = directory;
|
|
this.appVersion = appVersion;
|
|
this.journalFile = new File(directory, JOURNAL_FILE);
|
|
this.journalFileTmp = new File(directory, JOURNAL_FILE_TEMP);
|
|
this.journalFileBackup = new File(directory, JOURNAL_FILE_BACKUP);
|
|
this.valueCount = valueCount;
|
|
this.maxSize = maxSize;
|
|
}
|
|
|
|
/**
|
|
* Opens the cache in {@code directory}, creating a cache if none exists there.
|
|
*
|
|
* @param directory
|
|
* a writable directory
|
|
* @param valueCount
|
|
* the number of values per cache entry. Must be positive.
|
|
* @param maxSize
|
|
* the maximum number of bytes this cache should use to store
|
|
* @throws IOException
|
|
* if reading or writing the cache directory fails
|
|
*/
|
|
public static DiskLruCache open(File directory, int appVersion, int valueCount, long maxSize) throws IOException {
|
|
if (maxSize <= 0) {
|
|
throw new IllegalArgumentException("maxSize <= 0");
|
|
}
|
|
if (valueCount <= 0) {
|
|
throw new IllegalArgumentException("valueCount <= 0");
|
|
}
|
|
|
|
// If a bkp file exists, use it instead.
|
|
File backupFile = new File(directory, JOURNAL_FILE_BACKUP);
|
|
if (backupFile.exists()) {
|
|
File journalFile = new File(directory, JOURNAL_FILE);
|
|
// If journal file also exists just delete backup file.
|
|
if (journalFile.exists()) {
|
|
backupFile.delete();
|
|
} else {
|
|
renameTo(backupFile, journalFile, false);
|
|
}
|
|
}
|
|
|
|
// Prefer to pick up where we left off.
|
|
DiskLruCache cache = new DiskLruCache(directory, appVersion, valueCount, maxSize);
|
|
if (cache.journalFile.exists()) {
|
|
try {
|
|
cache.readJournal();
|
|
cache.processJournal();
|
|
return cache;
|
|
} catch (IOException journalIsCorrupt) {
|
|
if (LOGGER.isWarnEnabled()) {
|
|
LOGGER.warn("DiskLruCache " + directory + " is corrupt - removing", journalIsCorrupt);
|
|
}
|
|
cache.delete();
|
|
}
|
|
}
|
|
|
|
// Create a new empty cache.
|
|
directory.mkdirs();
|
|
cache = new DiskLruCache(directory, appVersion, valueCount, maxSize);
|
|
cache.rebuildJournal();
|
|
return cache;
|
|
}
|
|
|
|
private void readJournal() throws IOException {
|
|
StrictLineReader reader = new StrictLineReader(new FileInputStream(journalFile), StandardCharsets.UTF_8);
|
|
try {
|
|
String magic = reader.readLine();
|
|
String version = reader.readLine();
|
|
String appVersionString = reader.readLine();
|
|
String valueCountString = reader.readLine();
|
|
String blank = reader.readLine();
|
|
if (!MAGIC.equals(magic) || !VERSION_1.equals(version)
|
|
|| !Integer.toString(appVersion).equals(appVersionString)
|
|
|| !Integer.toString(valueCount).equals(valueCountString) || !"".equals(blank)) {
|
|
throw new IOException("unexpected journal header: [" + magic + ", " + version + ", " + valueCountString
|
|
+ ", " + blank + "]");
|
|
}
|
|
|
|
int lineCount = 0;
|
|
while (true) {
|
|
try {
|
|
readJournalLine(reader.readLine());
|
|
lineCount++;
|
|
} catch (EOFException endOfJournal) {
|
|
break;
|
|
}
|
|
}
|
|
redundantOpCount = lineCount - lruEntries.size();
|
|
|
|
// If we ended on a truncated line, rebuild the journal before appending to it.
|
|
if (reader.hasUnterminatedLine()) {
|
|
rebuildJournal();
|
|
} else {
|
|
journalWriter = new BufferedWriter(
|
|
new OutputStreamWriter(new FileOutputStream(journalFile, true), StandardCharsets.UTF_8));
|
|
}
|
|
} finally {
|
|
Util.closeQuietly(reader);
|
|
}
|
|
}
|
|
|
|
private void readJournalLine(String line) throws IOException {
|
|
int firstSpace = line.indexOf(' ');
|
|
if (firstSpace == -1) {
|
|
throw new IOException("unexpected journal line: " + line);
|
|
}
|
|
|
|
int keyBegin = firstSpace + 1;
|
|
int secondSpace = line.indexOf(' ', keyBegin);
|
|
final String key;
|
|
if (secondSpace == -1) {
|
|
key = line.substring(keyBegin);
|
|
if (firstSpace == REMOVE.length() && line.startsWith(REMOVE)) {
|
|
lruEntries.remove(key);
|
|
return;
|
|
}
|
|
} else {
|
|
key = line.substring(keyBegin, secondSpace);
|
|
}
|
|
|
|
Entry entry = lruEntries.get(key);
|
|
if (entry == null) {
|
|
entry = new Entry(key);
|
|
lruEntries.put(key, entry);
|
|
}
|
|
|
|
if (secondSpace != -1 && firstSpace == CLEAN.length() && line.startsWith(CLEAN)) {
|
|
String[] parts = line.substring(secondSpace + 1).split(" ");
|
|
entry.readable = true;
|
|
entry.currentEditor = null;
|
|
entry.setLengths(parts);
|
|
} else if (secondSpace == -1 && firstSpace == DIRTY.length() && line.startsWith(DIRTY)) {
|
|
entry.currentEditor = new Editor(entry);
|
|
} else if (secondSpace == -1 && firstSpace == READ.length() && line.startsWith(READ)) {
|
|
// This work was already done by calling lruEntries.get().
|
|
} else {
|
|
throw new IOException("unexpected journal line: " + line);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Computes the initial size and collects garbage as a part of opening the
|
|
* cache. Dirty entries are assumed to be inconsistent and will be deleted.
|
|
*/
|
|
private void processJournal() throws IOException {
|
|
deleteIfExists(journalFileTmp);
|
|
for (Iterator<Entry> i = lruEntries.values().iterator(); i.hasNext();) {
|
|
Entry entry = i.next();
|
|
if (entry.currentEditor == null) {
|
|
for (int t = 0; t < valueCount; t++) {
|
|
size += entry.lengths[t];
|
|
}
|
|
} else {
|
|
entry.currentEditor = null;
|
|
for (int t = 0; t < valueCount; t++) {
|
|
deleteIfExists(entry.getCleanFile(t));
|
|
deleteIfExists(entry.getDirtyFile(t));
|
|
}
|
|
i.remove();
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Creates a new journal that omits redundant information. This replaces the
|
|
* current journal if it exists.
|
|
*/
|
|
private synchronized void rebuildJournal() throws IOException {
|
|
if (journalWriter != null) {
|
|
journalWriter.close();
|
|
}
|
|
|
|
Writer writer = new BufferedWriter(
|
|
new OutputStreamWriter(new FileOutputStream(journalFileTmp), StandardCharsets.UTF_8));
|
|
try {
|
|
writer.write(MAGIC);
|
|
writer.write("\n");
|
|
writer.write(VERSION_1);
|
|
writer.write("\n");
|
|
writer.write(Integer.toString(appVersion));
|
|
writer.write("\n");
|
|
writer.write(Integer.toString(valueCount));
|
|
writer.write("\n");
|
|
writer.write("\n");
|
|
|
|
for (Entry entry : lruEntries.values()) {
|
|
if (entry.currentEditor != null) {
|
|
writer.write(DIRTY + ' ' + entry.key + '\n');
|
|
} else {
|
|
writer.write(CLEAN + ' ' + entry.key + entry.getLengths() + '\n');
|
|
}
|
|
}
|
|
} finally {
|
|
Util.closeQuietly(writer);
|
|
}
|
|
|
|
if (journalFile.exists()) {
|
|
renameTo(journalFile, journalFileBackup, true);
|
|
}
|
|
renameTo(journalFileTmp, journalFile, false);
|
|
journalFileBackup.delete();
|
|
|
|
journalWriter = new BufferedWriter(
|
|
new OutputStreamWriter(new FileOutputStream(journalFile, true), StandardCharsets.UTF_8));
|
|
}
|
|
|
|
private static void deleteIfExists(File file) throws IOException {
|
|
if (file.exists() && !file.delete()) {
|
|
throw new IOException();
|
|
}
|
|
}
|
|
|
|
private static void renameTo(File from, File to, boolean deleteDestination) throws IOException {
|
|
if (deleteDestination) {
|
|
deleteIfExists(to);
|
|
}
|
|
if (!from.renameTo(to)) {
|
|
throw new IOException();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Returns a snapshot of the entry named {@code key}, or null if it doesn't
|
|
* exist is not currently readable. If a value is returned, it is moved to the
|
|
* head of the LRU queue.
|
|
*/
|
|
public synchronized Snapshot get(String key) throws IOException {
|
|
checkNotClosed();
|
|
validateKey(key);
|
|
Entry entry = lruEntries.get(key);
|
|
if (entry == null) {
|
|
return null;
|
|
}
|
|
|
|
if (!entry.readable) {
|
|
return null;
|
|
}
|
|
|
|
// Open all streams eagerly to guarantee that we see a single published
|
|
// snapshot. If we opened streams lazily then the streams could come
|
|
// from different edits.
|
|
InputStream[] ins = new InputStream[valueCount];
|
|
try {
|
|
for (int i = 0; i < valueCount; i++) {
|
|
ins[i] = new FileInputStream(entry.getCleanFile(i));
|
|
}
|
|
} catch (FileNotFoundException e) {
|
|
// A file must have been deleted manually!
|
|
for (int i = 0; i < valueCount; i++) {
|
|
if (ins[i] != null) {
|
|
Util.closeQuietly(ins[i]);
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
return null;
|
|
}
|
|
|
|
redundantOpCount++;
|
|
journalWriter.append(READ + ' ').append(key).append(String.valueOf('\n'));
|
|
if (journalRebuildRequired()) {
|
|
executorService.submit(cleanupCallable);
|
|
}
|
|
|
|
return new Snapshot(key, entry.sequenceNumber, ins, entry.lengths);
|
|
}
|
|
|
|
/**
|
|
* Returns an editor for the entry named {@code key}, or null if another edit is
|
|
* in progress.
|
|
*/
|
|
public Editor edit(String key) throws IOException {
|
|
return edit(key, ANY_SEQUENCE_NUMBER);
|
|
}
|
|
|
|
private synchronized Editor edit(String key, long expectedSequenceNumber) throws IOException {
|
|
checkNotClosed();
|
|
validateKey(key);
|
|
Entry entry = lruEntries.get(key);
|
|
if (expectedSequenceNumber != ANY_SEQUENCE_NUMBER
|
|
&& (entry == null || entry.sequenceNumber != expectedSequenceNumber)) {
|
|
return null; // Snapshot is stale.
|
|
}
|
|
if (entry == null) {
|
|
entry = new Entry(key);
|
|
lruEntries.put(key, entry);
|
|
} else if (entry.currentEditor != null) {
|
|
return null; // Another edit is in progress.
|
|
}
|
|
|
|
Editor editor = new Editor(entry);
|
|
entry.currentEditor = editor;
|
|
|
|
// Flush the journal before creating files to prevent file leaks.
|
|
journalWriter.write(DIRTY + ' ' + key + '\n');
|
|
journalWriter.flush();
|
|
return editor;
|
|
}
|
|
|
|
/** Returns the directory where this cache stores its data. */
|
|
public File getDirectory() {
|
|
return directory;
|
|
}
|
|
|
|
/**
|
|
* Returns the maximum number of bytes that this cache should use to store its
|
|
* data.
|
|
*/
|
|
public synchronized long getMaxSize() {
|
|
return maxSize;
|
|
}
|
|
|
|
/**
|
|
* Changes the maximum number of bytes the cache can store and queues a job to
|
|
* trim the existing store, if necessary.
|
|
*/
|
|
public synchronized void setMaxSize(long maxSize) {
|
|
this.maxSize = maxSize;
|
|
executorService.submit(cleanupCallable);
|
|
}
|
|
|
|
/**
|
|
* Returns the number of bytes currently being used to store the values in this
|
|
* cache. This may be greater than the max size if a background deletion is
|
|
* pending.
|
|
*/
|
|
public synchronized long size() {
|
|
return size;
|
|
}
|
|
|
|
private synchronized void completeEdit(Editor editor, boolean success) throws IOException {
|
|
Entry entry = editor.entry;
|
|
if (entry.currentEditor != editor) {
|
|
throw new IllegalStateException();
|
|
}
|
|
|
|
// If this edit is creating the entry for the first time, every index must have
|
|
// a value.
|
|
if (success && !entry.readable) {
|
|
for (int i = 0; i < valueCount; i++) {
|
|
if (!editor.written[i]) {
|
|
editor.abort();
|
|
throw new IllegalStateException("Newly created entry didn't create value for index " + i);
|
|
}
|
|
if (!entry.getDirtyFile(i).exists()) {
|
|
editor.abort();
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
for (int i = 0; i < valueCount; i++) {
|
|
File dirty = entry.getDirtyFile(i);
|
|
if (success) {
|
|
if (dirty.exists()) {
|
|
File clean = entry.getCleanFile(i);
|
|
dirty.renameTo(clean);
|
|
long oldLength = entry.lengths[i];
|
|
long newLength = clean.length();
|
|
entry.lengths[i] = newLength;
|
|
size = size - oldLength + newLength;
|
|
}
|
|
} else {
|
|
deleteIfExists(dirty);
|
|
}
|
|
}
|
|
|
|
redundantOpCount++;
|
|
entry.currentEditor = null;
|
|
if (entry.readable | success) {
|
|
entry.readable = true;
|
|
journalWriter.write(CLEAN + ' ' + entry.key + entry.getLengths() + '\n');
|
|
if (success) {
|
|
entry.sequenceNumber = nextSequenceNumber++;
|
|
}
|
|
} else {
|
|
lruEntries.remove(entry.key);
|
|
journalWriter.write(REMOVE + ' ' + entry.key + '\n');
|
|
}
|
|
journalWriter.flush();
|
|
|
|
if (size > maxSize || journalRebuildRequired()) {
|
|
executorService.submit(cleanupCallable);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* We only rebuild the journal when it will halve the size of the journal and
|
|
* eliminate at least 2000 ops.
|
|
*/
|
|
private boolean journalRebuildRequired() {
|
|
final int redundantOpCompactThreshold = 2000;
|
|
return redundantOpCount >= redundantOpCompactThreshold //
|
|
&& redundantOpCount >= lruEntries.size();
|
|
}
|
|
|
|
/**
|
|
* Drops the entry for {@code key} if it exists and can be removed. Entries
|
|
* actively being edited cannot be removed.
|
|
*
|
|
* @return true if an entry was removed.
|
|
*/
|
|
public synchronized boolean remove(String key) throws IOException {
|
|
checkNotClosed();
|
|
validateKey(key);
|
|
Entry entry = lruEntries.get(key);
|
|
if (entry == null || entry.currentEditor != null) {
|
|
return false;
|
|
}
|
|
|
|
for (int i = 0; i < valueCount; i++) {
|
|
File file = entry.getCleanFile(i);
|
|
if (file.exists() && !file.delete()) {
|
|
throw new IOException("failed to delete " + file);
|
|
}
|
|
size -= entry.lengths[i];
|
|
entry.lengths[i] = 0;
|
|
}
|
|
|
|
redundantOpCount++;
|
|
journalWriter.append(REMOVE + ' ' + key + '\n');
|
|
lruEntries.remove(key);
|
|
|
|
if (journalRebuildRequired()) {
|
|
executorService.submit(cleanupCallable);
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/** Returns true if this cache has been closed. */
|
|
public synchronized boolean isClosed() {
|
|
return journalWriter == null;
|
|
}
|
|
|
|
private void checkNotClosed() {
|
|
if (journalWriter == null) {
|
|
throw new IllegalStateException("cache is closed");
|
|
}
|
|
}
|
|
|
|
/** Force buffered operations to the filesystem. */
|
|
public synchronized void flush() throws IOException {
|
|
checkNotClosed();
|
|
trimToSize();
|
|
journalWriter.flush();
|
|
}
|
|
|
|
/** Closes this cache. Stored values will remain on the filesystem. */
|
|
public synchronized void close() throws IOException {
|
|
if (journalWriter == null) {
|
|
return; // Already closed.
|
|
}
|
|
for (Entry entry : new ArrayList<>(lruEntries.values())) {
|
|
if (entry.currentEditor != null) {
|
|
entry.currentEditor.abort();
|
|
}
|
|
}
|
|
trimToSize();
|
|
journalWriter.close();
|
|
journalWriter = null;
|
|
}
|
|
|
|
private void trimToSize() throws IOException {
|
|
while (size > maxSize) {
|
|
Map.Entry<String, Entry> toEvict = lruEntries.entrySet().iterator().next();
|
|
remove(toEvict.getKey());
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Closes the cache and deletes all of its stored values. This will delete all
|
|
* files in the cache directory including files that weren't created by the
|
|
* cache.
|
|
*/
|
|
public void delete() throws IOException {
|
|
close();
|
|
Util.deleteContents(directory);
|
|
}
|
|
|
|
private void validateKey(String key) {
|
|
Matcher matcher = LEGAL_KEY_PATTERN.matcher(key);
|
|
if (!matcher.matches()) {
|
|
throw new IllegalArgumentException("keys must match regex " + STRING_KEY_PATTERN + ": \"" + key + "\"");
|
|
}
|
|
}
|
|
|
|
/** A snapshot of the values for an entry. */
|
|
public final class Snapshot implements Closeable {
|
|
private final String key;
|
|
private final long sequenceNumber;
|
|
private final InputStream[] ins;
|
|
private final long[] lengths;
|
|
|
|
private Snapshot(String key, long sequenceNumber, InputStream[] ins, long[] lengths) {
|
|
this.key = key;
|
|
this.sequenceNumber = sequenceNumber;
|
|
this.ins = ins;
|
|
this.lengths = lengths;
|
|
}
|
|
|
|
/**
|
|
* Returns an editor for this snapshot's entry, or null if either the entry has
|
|
* changed since this snapshot was created or if another edit is in progress.
|
|
*/
|
|
public Editor edit() throws IOException {
|
|
return DiskLruCache.this.edit(key, sequenceNumber);
|
|
}
|
|
|
|
/** Returns the unbuffered stream with the value for {@code index}. */
|
|
public InputStream getInputStream(int index) {
|
|
return ins[index];
|
|
}
|
|
|
|
/** Returns the string value for {@code index}. */
|
|
public String getString(int index) throws IOException {
|
|
try (InputStream in = getInputStream(index)) {
|
|
return IOUtils.toString(in, StandardCharsets.UTF_8);
|
|
}
|
|
}
|
|
|
|
/** Returns the byte length of the value for {@code index}. */
|
|
public long getLength(int index) {
|
|
return lengths[index];
|
|
}
|
|
|
|
public void close() {
|
|
for (InputStream in : ins) {
|
|
Util.closeQuietly(in);
|
|
}
|
|
}
|
|
}
|
|
|
|
private static final OutputStream NULL_OUTPUT_STREAM = new OutputStream() {
|
|
@Override
|
|
public void write(int b) {
|
|
// Eat all writes silently. Nom nom.
|
|
}
|
|
};
|
|
|
|
/** Edits the values for an entry. */
|
|
public final class Editor {
|
|
private final Entry entry;
|
|
private final boolean[] written;
|
|
private boolean hasErrors;
|
|
private boolean committed;
|
|
|
|
private Editor(Entry entry) {
|
|
this.entry = entry;
|
|
this.written = (entry.readable) ? null : new boolean[valueCount];
|
|
}
|
|
|
|
/**
|
|
* Returns an unbuffered input stream to read the last committed value, or null
|
|
* if no value has been committed.
|
|
*/
|
|
public InputStream newInputStream(int index) throws IOException {
|
|
synchronized (DiskLruCache.this) {
|
|
if (entry.currentEditor != this) {
|
|
throw new IllegalStateException();
|
|
}
|
|
if (!entry.readable) {
|
|
return null;
|
|
}
|
|
try {
|
|
return new FileInputStream(entry.getCleanFile(index));
|
|
} catch (FileNotFoundException e) {
|
|
return null;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Returns the last committed value as a string, or null if no value has been
|
|
* committed.
|
|
*/
|
|
public String getString(int index) throws IOException {
|
|
InputStream in = newInputStream(index);
|
|
try {
|
|
return in != null ? IOUtils.toString(in, StandardCharsets.UTF_8) : null;
|
|
} finally {
|
|
Util.closeQuietly(in);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Write a string to the specified index.
|
|
*/
|
|
public void setString(int index, String value) throws IOException {
|
|
OutputStream out = newOutputStream(index);
|
|
try {
|
|
IOUtils.write(value, out, StandardCharsets.UTF_8);
|
|
} finally {
|
|
Util.closeQuietly(out);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Returns a new unbuffered output stream to write the value at {@code index}.
|
|
* If the underlying output stream encounters errors when writing to the
|
|
* filesystem, this edit will be aborted when {@link #commit} is called. The
|
|
* returned output stream does not throw IOExceptions.
|
|
*/
|
|
public OutputStream newOutputStream(int index) {
|
|
if (index < 0 || index >= valueCount) {
|
|
throw new IllegalArgumentException("Expected index " + index + " to "
|
|
+ "be greater than 0 and less than the maximum value count " + "of " + valueCount);
|
|
}
|
|
synchronized (DiskLruCache.this) {
|
|
if (entry.currentEditor != this) {
|
|
throw new IllegalStateException();
|
|
}
|
|
if (!entry.readable) {
|
|
written[index] = true;
|
|
}
|
|
File dirtyFile = entry.getDirtyFile(index);
|
|
FileOutputStream outputStream;
|
|
try {
|
|
outputStream = new FileOutputStream(dirtyFile);
|
|
} catch (FileNotFoundException e) {
|
|
// Attempt to recreate the cache directory.
|
|
directory.mkdirs();
|
|
try {
|
|
outputStream = new FileOutputStream(dirtyFile);
|
|
} catch (FileNotFoundException e2) {
|
|
// We are unable to recover. Silently eat the writes.
|
|
return NULL_OUTPUT_STREAM;
|
|
}
|
|
}
|
|
return new FaultHidingOutputStream(outputStream);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Commits this edit so it is visible to readers. This releases the edit lock so
|
|
* another edit may be started on the same key.
|
|
*/
|
|
public void commit() throws IOException {
|
|
if (hasErrors) {
|
|
completeEdit(this, false);
|
|
remove(entry.key); // The previous entry is stale.
|
|
} else {
|
|
completeEdit(this, true);
|
|
}
|
|
committed = true;
|
|
}
|
|
|
|
/**
|
|
* Aborts this edit. This releases the edit lock so another edit may be started
|
|
* on the same key.
|
|
*/
|
|
public void abort() throws IOException {
|
|
completeEdit(this, false);
|
|
}
|
|
|
|
public long getLength(int index) {
|
|
return entry.getDirtyFile(index).length();
|
|
}
|
|
|
|
public void abortUnlessCommitted() {
|
|
if (!committed) {
|
|
try {
|
|
abort();
|
|
} catch (IOException ignored) {
|
|
}
|
|
}
|
|
}
|
|
|
|
private class FaultHidingOutputStream extends FilterOutputStream {
|
|
private FaultHidingOutputStream(OutputStream out) {
|
|
super(out);
|
|
}
|
|
|
|
@Override
|
|
public void write(int oneByte) {
|
|
try {
|
|
out.write(oneByte);
|
|
} catch (IOException e) {
|
|
hasErrors = true;
|
|
}
|
|
}
|
|
|
|
@Override
|
|
public void write(byte[] buffer, int offset, int length) {
|
|
try {
|
|
out.write(buffer, offset, length);
|
|
} catch (IOException e) {
|
|
hasErrors = true;
|
|
}
|
|
}
|
|
|
|
@Override
|
|
public void close() {
|
|
try {
|
|
out.close();
|
|
} catch (IOException e) {
|
|
hasErrors = true;
|
|
}
|
|
}
|
|
|
|
@Override
|
|
public void flush() {
|
|
try {
|
|
out.flush();
|
|
} catch (IOException e) {
|
|
hasErrors = true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
private final class Entry {
|
|
private final String key;
|
|
|
|
/** Lengths of this entry's files. */
|
|
private final long[] lengths;
|
|
|
|
/** True if this entry has ever been published. */
|
|
private boolean readable;
|
|
|
|
/** The ongoing edit or null if this entry is not being edited. */
|
|
private Editor currentEditor;
|
|
|
|
/** The sequence number of the most recently committed edit to this entry. */
|
|
private long sequenceNumber;
|
|
|
|
private Entry(String key) {
|
|
this.key = key;
|
|
this.lengths = new long[valueCount];
|
|
}
|
|
|
|
public String getLengths() {
|
|
StringBuilder result = new StringBuilder();
|
|
for (long size : lengths) {
|
|
result.append(' ').append(size);
|
|
}
|
|
return result.toString();
|
|
}
|
|
|
|
/** Set lengths using decimal numbers like "10123". */
|
|
private void setLengths(String[] strings) throws IOException {
|
|
if (strings.length != valueCount) {
|
|
throw invalidLengths(strings);
|
|
}
|
|
|
|
try {
|
|
for (int i = 0; i < strings.length; i++) {
|
|
lengths[i] = Long.parseLong(strings[i]);
|
|
}
|
|
} catch (NumberFormatException e) {
|
|
throw invalidLengths(strings);
|
|
}
|
|
}
|
|
|
|
private IOException invalidLengths(String[] strings) throws IOException {
|
|
throw new IOException("unexpected journal line: " + java.util.Arrays.toString(strings));
|
|
}
|
|
|
|
public File getCleanFile(int i) {
|
|
return new File(directory, key + "." + i);
|
|
}
|
|
|
|
public File getDirtyFile(int i) {
|
|
return new File(directory, key + "." + i + ".tmp");
|
|
}
|
|
}
|
|
}
|