Java 类com.google.android.exoplayer2.util.AtomicFile 实例源码

/**
 * Creates a CachedContentIndex which works on the index file in the given cacheDir.
 *
 * @param cacheDir Directory where the index file is kept.
 * @param secretKey If not null, cache keys will be stored encrypted on filesystem using AES/CBC.
 *     The key must be 16 bytes long.
 */
public CachedContentIndex(File cacheDir, byte[] secretKey) {
  if (secretKey != null) {
    Assertions.checkArgument(secretKey.length == 16);
    try {
      cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
      secretKeySpec = new SecretKeySpec(secretKey, "AES");
    } catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
      throw new IllegalStateException(e); // Should never happen.
    }
  } else {
    cipher = null;
    secretKeySpec = null;
  }
  keyToContent = new HashMap<>();
  idToKey = new SparseArray<>();
  atomicFile = new AtomicFile(new File(cacheDir, FILE_NAME));
}

/**
 * Creates a CachedContentIndex which works on the index file in the given cacheDir.
 *
 * @param cacheDir Directory where the index file is kept.
 * @param secretKey If not null, cache keys will be stored encrypted on filesystem using AES/CBC.
 *     The key must be 16 bytes long.
 */
public CachedContentIndex(File cacheDir, byte[] secretKey) {
  if (secretKey != null) {
    Assertions.checkArgument(secretKey.length == 16);
    try {
      cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
      secretKeySpec = new SecretKeySpec(secretKey, "AES");
    } catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
      throw new IllegalStateException(e); // Should never happen.
    }
  } else {
    cipher = null;
    secretKeySpec = null;
  }
  keyToContent = new HashMap<>();
  idToKey = new SparseArray<>();
  atomicFile = new AtomicFile(new File(cacheDir, FILE_NAME));
}

/**
 * Creates a CachedContentIndex which works on the index file in the given cacheDir.
 *
 * @param cacheDir Directory where the index file is kept.
 * @param secretKey 16 byte AES key for reading, and optionally writing, the cache index.
 * @param encrypt Whether the index will be encrypted when written. Must be false if {@code
 *     secretKey} is null.
 */
public CachedContentIndex(File cacheDir, byte[] secretKey, boolean encrypt) {
  this.encrypt = encrypt;
  if (secretKey != null) {
    Assertions.checkArgument(secretKey.length == 16);
    try {
      cipher = getCipher();
      secretKeySpec = new SecretKeySpec(secretKey, "AES");
    } catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
      throw new IllegalStateException(e); // Should never happen.
    }
  } else {
    Assertions.checkState(!encrypt);
    cipher = null;
    secretKeySpec = null;
  }
  keyToContent = new HashMap<>();
  idToKey = new SparseArray<>();
  atomicFile = new AtomicFile(new File(cacheDir, FILE_NAME));
}