Bug 1290014 - Add DiskLruCache library. r=ahunt,Grisha
authorSebastian Kaspari <s.kaspari@gmail.com>
Wed, 27 Jul 2016 16:20:00 +0200
changeset 353645 1e8ebfb60a17b01fa25bd8557715a9002faf675f
parent 353644 347ed1510d82b1963573344a70e40f0903309b02
child 353646 7d65390d95e755b5cfd6896e0f564b41e6f47e7f
push id6570
push userraliiev@mozilla.com
push dateMon, 14 Nov 2016 12:26:13 +0000
treeherdermozilla-beta@f455459b2ae5 [default view] [failures only]
perfherder[talos] [build metrics] [platform microbench] (compared to previous push)
reviewersahunt, Grisha
bugs1290014, 1108084
milestone51.0a1
first release with
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
last release without
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
Bug 1290014 - Add DiskLruCache library. r=ahunt,Grisha This patch adds the known and widely used disk LRU cache library by Jake Wharton [1]. It's a standalone version of the disk LRU cache found in the AOSP tree. The goal is to use a flat file disk cache to avoid the overhead of storing blobs in a database [2] (and some bugs like bug 1108084). [1] https://github.com/JakeWharton/DiskLruCache [2] https://wiki.mozilla.org/Performance/Avoid_SQLite_In_Your_Next_Firefox_Feature MozReview-Commit-ID: 2ayN7SYVe4W
mobile/android/base/moz.build
mobile/android/thirdparty/com/jakewharton/disklrucache/DiskLruCache.java
mobile/android/thirdparty/com/jakewharton/disklrucache/StrictLineReader.java
mobile/android/thirdparty/com/jakewharton/disklrucache/Util.java
--- a/mobile/android/base/moz.build
+++ b/mobile/android/base/moz.build
@@ -857,16 +857,19 @@ gbjar.extra_jars += [CONFIG['ANDROID_DES
 gbjar.extra_jars += [CONFIG['ANDROID_RECYCLERVIEW_V7_AAR_LIB']]
 gbjar.extra_jars += [CONFIG['ANDROID_CUSTOMTABS_AAR_LIB']]
 
 gbjar.javac_flags += ['-Xlint:all,-deprecation,-fallthrough', '-J-Xmx512m', '-J-Xms128m']
 
 # gecko-thirdparty is a good place to put small independent libraries
 gtjar = add_java_jar('gecko-thirdparty')
 gtjar.sources += [ thirdparty_source_dir + f for f in [
+    'com/jakewharton/disklrucache/DiskLruCache.java',
+    'com/jakewharton/disklrucache/StrictLineReader.java',
+    'com/jakewharton/disklrucache/Util.java',
     'com/keepsafe/switchboard/AsyncConfigLoader.java',
     'com/keepsafe/switchboard/DeviceUuidFactory.java',
     'com/keepsafe/switchboard/Preferences.java',
     'com/keepsafe/switchboard/Switch.java',
     'com/keepsafe/switchboard/SwitchBoard.java',
     'com/squareup/leakcanary/LeakCanary.java',
     'com/squareup/leakcanary/RefWatcher.java',
     'com/squareup/picasso/Action.java',
new file mode 100644
--- /dev/null
+++ b/mobile/android/thirdparty/com/jakewharton/disklrucache/DiskLruCache.java
@@ -0,0 +1,943 @@
+/*
+ * 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 com.jakewharton.disklrucache;
+
+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.InputStreamReader;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+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 {
+  static final String JOURNAL_FILE = "journal";
+  static final String JOURNAL_FILE_TEMP = "journal.tmp";
+  static final String JOURNAL_FILE_BACKUP = "journal.bkp";
+  static final String MAGIC = "libcore.io.DiskLruCache";
+  static final String VERSION_1 = "1";
+  static final long ANY_SEQUENCE_NUMBER = -1;
+  static final String STRING_KEY_PATTERN = "[a-z0-9_-]{1,120}";
+  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<String, Entry>(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<Runnable>());
+  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) {
+        System.out
+            .println("DiskLruCache "
+                + directory
+                + " is corrupt: "
+                + journalIsCorrupt.getMessage()
+                + ", removing");
+        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), Util.US_ASCII);
+    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), Util.US_ASCII));
+      }
+    } 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), Util.US_ASCII));
+    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 {
+      writer.close();
+    }
+
+    if (journalFile.exists()) {
+      renameTo(journalFile, journalFileBackup, true);
+    }
+    renameTo(journalFileTmp, journalFile, false);
+    journalFileBackup.delete();
+
+    journalWriter = new BufferedWriter(
+        new OutputStreamWriter(new FileOutputStream(journalFile, true), Util.US_ASCII));
+  }
+
+  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 + ' ' + key + '\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<Entry>(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 + "\"");
+    }
+  }
+
+  private static String inputStreamToString(InputStream in) throws IOException {
+    return Util.readFully(new InputStreamReader(in, Util.UTF_8));
+  }
+
+  /** 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 {
+      return inputStreamToString(getInputStream(index));
+    }
+
+    /** 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) throws IOException {
+      // 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);
+      return in != null ? inputStreamToString(in) : null;
+    }
+
+    /**
+     * 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) throws IOException {
+      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);
+      }
+    }
+
+    /** Sets the value at {@code index} to {@code value}. */
+    public void set(int index, String value) throws IOException {
+      Writer writer = null;
+      try {
+        writer = new OutputStreamWriter(newOutputStream(index), Util.UTF_8);
+        writer.write(value);
+      } finally {
+        Util.closeQuietly(writer);
+      }
+    }
+
+    /**
+     * 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 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() throws IOException {
+      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");
+    }
+  }
+}
new file mode 100644
--- /dev/null
+++ b/mobile/android/thirdparty/com/jakewharton/disklrucache/StrictLineReader.java
@@ -0,0 +1,196 @@
+/*
+ * Copyright (C) 2012 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 com.jakewharton.disklrucache;
+
+import java.io.ByteArrayOutputStream;
+import java.io.Closeable;
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.UnsupportedEncodingException;
+import java.nio.charset.Charset;
+
+/**
+ * Buffers input from an {@link InputStream} for reading lines.
+ *
+ * <p>This class is used for buffered reading of lines. For purposes of this class, a line ends
+ * with "\n" or "\r\n". End of input is reported by throwing {@code EOFException}. Unterminated
+ * line at end of input is invalid and will be ignored, the caller may use {@code
+ * hasUnterminatedLine()} to detect it after catching the {@code EOFException}.
+ *
+ * <p>This class is intended for reading input that strictly consists of lines, such as line-based
+ * cache entries or cache journal. Unlike the {@link java.io.BufferedReader} which in conjunction
+ * with {@link java.io.InputStreamReader} provides similar functionality, this class uses different
+ * end-of-input reporting and a more restrictive definition of a line.
+ *
+ * <p>This class supports only charsets that encode '\r' and '\n' as a single byte with value 13
+ * and 10, respectively, and the representation of no other character contains these values.
+ * We currently check in constructor that the charset is one of US-ASCII, UTF-8 and ISO-8859-1.
+ * The default charset is US_ASCII.
+ */
+class StrictLineReader implements Closeable {
+  private static final byte CR = (byte) '\r';
+  private static final byte LF = (byte) '\n';
+
+  private final InputStream in;
+  private final Charset charset;
+
+  /*
+   * Buffered data is stored in {@code buf}. As long as no exception occurs, 0 <= pos <= end
+   * and the data in the range [pos, end) is buffered for reading. At end of input, if there is
+   * an unterminated line, we set end == -1, otherwise end == pos. If the underlying
+   * {@code InputStream} throws an {@code IOException}, end may remain as either pos or -1.
+   */
+  private byte[] buf;
+  private int pos;
+  private int end;
+
+  /**
+   * Constructs a new {@code LineReader} with the specified charset and the default capacity.
+   *
+   * @param in the {@code InputStream} to read data from.
+   * @param charset the charset used to decode data. Only US-ASCII, UTF-8 and ISO-8859-1 are
+   * supported.
+   * @throws NullPointerException if {@code in} or {@code charset} is null.
+   * @throws IllegalArgumentException if the specified charset is not supported.
+   */
+  public StrictLineReader(InputStream in, Charset charset) {
+    this(in, 8192, charset);
+  }
+
+  /**
+   * Constructs a new {@code LineReader} with the specified capacity and charset.
+   *
+   * @param in the {@code InputStream} to read data from.
+   * @param capacity the capacity of the buffer.
+   * @param charset the charset used to decode data. Only US-ASCII, UTF-8 and ISO-8859-1 are
+   * supported.
+   * @throws NullPointerException if {@code in} or {@code charset} is null.
+   * @throws IllegalArgumentException if {@code capacity} is negative or zero
+   * or the specified charset is not supported.
+   */
+  public StrictLineReader(InputStream in, int capacity, Charset charset) {
+    if (in == null || charset == null) {
+      throw new NullPointerException();
+    }
+    if (capacity < 0) {
+      throw new IllegalArgumentException("capacity <= 0");
+    }
+    if (!(charset.equals(Util.US_ASCII))) {
+      throw new IllegalArgumentException("Unsupported encoding");
+    }
+
+    this.in = in;
+    this.charset = charset;
+    buf = new byte[capacity];
+  }
+
+  /**
+   * Closes the reader by closing the underlying {@code InputStream} and
+   * marking this reader as closed.
+   *
+   * @throws IOException for errors when closing the underlying {@code InputStream}.
+   */
+  public void close() throws IOException {
+    synchronized (in) {
+      if (buf != null) {
+        buf = null;
+        in.close();
+      }
+    }
+  }
+
+  /**
+   * Reads the next line. A line ends with {@code "\n"} or {@code "\r\n"},
+   * this end of line marker is not included in the result.
+   *
+   * @return the next line from the input.
+   * @throws IOException for underlying {@code InputStream} errors.
+   * @throws EOFException for the end of source stream.
+   */
+  public String readLine() throws IOException {
+    synchronized (in) {
+      if (buf == null) {
+        throw new IOException("LineReader is closed");
+      }
+
+      // Read more data if we are at the end of the buffered data.
+      // Though it's an error to read after an exception, we will let {@code fillBuf()}
+      // throw again if that happens; thus we need to handle end == -1 as well as end == pos.
+      if (pos >= end) {
+        fillBuf();
+      }
+      // Try to find LF in the buffered data and return the line if successful.
+      for (int i = pos; i != end; ++i) {
+        if (buf[i] == LF) {
+          int lineEnd = (i != pos && buf[i - 1] == CR) ? i - 1 : i;
+          String res = new String(buf, pos, lineEnd - pos, charset.name());
+          pos = i + 1;
+          return res;
+        }
+      }
+
+      // Let's anticipate up to 80 characters on top of those already read.
+      ByteArrayOutputStream out = new ByteArrayOutputStream(end - pos + 80) {
+        @Override
+        public String toString() {
+          int length = (count > 0 && buf[count - 1] == CR) ? count - 1 : count;
+          try {
+            return new String(buf, 0, length, charset.name());
+          } catch (UnsupportedEncodingException e) {
+            throw new AssertionError(e); // Since we control the charset this will never happen.
+          }
+        }
+      };
+
+      while (true) {
+        out.write(buf, pos, end - pos);
+        // Mark unterminated line in case fillBuf throws EOFException or IOException.
+        end = -1;
+        fillBuf();
+        // Try to find LF in the buffered data and return the line if successful.
+        for (int i = pos; i != end; ++i) {
+          if (buf[i] == LF) {
+            if (i != pos) {
+              out.write(buf, pos, i - pos);
+            }
+            pos = i + 1;
+            return out.toString();
+          }
+        }
+      }
+    }
+  }
+
+  public boolean hasUnterminatedLine() {
+    return end == -1;
+  }
+
+  /**
+   * Reads new input data into the buffer. Call only with pos == end or end == -1,
+   * depending on the desired outcome if the function throws.
+   */
+  private void fillBuf() throws IOException {
+    int result = in.read(buf, 0, buf.length);
+    if (result == -1) {
+      throw new EOFException();
+    }
+    pos = 0;
+    end = result;
+  }
+}
+
new file mode 100644
--- /dev/null
+++ b/mobile/android/thirdparty/com/jakewharton/disklrucache/Util.java
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2010 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 com.jakewharton.disklrucache;
+
+import java.io.Closeable;
+import java.io.File;
+import java.io.IOException;
+import java.io.Reader;
+import java.io.StringWriter;
+import java.nio.charset.Charset;
+
+/** Junk drawer of utility methods. */
+final class Util {
+  static final Charset US_ASCII = Charset.forName("US-ASCII");
+  static final Charset UTF_8 = Charset.forName("UTF-8");
+
+  private Util() {
+  }
+
+  static String readFully(Reader reader) throws IOException {
+    try {
+      StringWriter writer = new StringWriter();
+      char[] buffer = new char[1024];
+      int count;
+      while ((count = reader.read(buffer)) != -1) {
+        writer.write(buffer, 0, count);
+      }
+      return writer.toString();
+    } finally {
+      reader.close();
+    }
+  }
+
+  /**
+   * Deletes the contents of {@code dir}. Throws an IOException if any file
+   * could not be deleted, or if {@code dir} is not a readable directory.
+   */
+  static void deleteContents(File dir) throws IOException {
+    File[] files = dir.listFiles();
+    if (files == null) {
+      throw new IOException("not a readable directory: " + dir);
+    }
+    for (File file : files) {
+      if (file.isDirectory()) {
+        deleteContents(file);
+      }
+      if (!file.delete()) {
+        throw new IOException("failed to delete file: " + file);
+      }
+    }
+  }
+
+  static void closeQuietly(/*Auto*/Closeable closeable) {
+    if (closeable != null) {
+      try {
+        closeable.close();
+      } catch (RuntimeException rethrown) {
+        throw rethrown;
+      } catch (Exception ignored) {
+      }
+    }
+  }
+}