AttachmentDownloadJob.java 文件源码

@VisibleForTesting
SignalServiceAttachmentPointer createAttachmentPointer(MasterSecret masterSecret, Attachment attachment)
    throws InvalidPartException
{
  if (TextUtils.isEmpty(attachment.getLocation())) {
    throw new InvalidPartException("empty content id");
  }

  if (TextUtils.isEmpty(attachment.getKey())) {
    throw new InvalidPartException("empty encrypted key");
  }

  try {
    AsymmetricMasterSecret asymmetricMasterSecret = MasterSecretUtil.getAsymmetricMasterSecret(context, masterSecret);
    long                   id                     = Long.parseLong(attachment.getLocation());
    byte[]                 key                    = MediaKey.getDecrypted(masterSecret, asymmetricMasterSecret, attachment.getKey());
    String                 relay                  = null;

    if (TextUtils.isEmpty(attachment.getRelay())) {
      relay = attachment.getRelay();
    }

    return new SignalServiceAttachmentPointer(id, null, null, key, relay, Optional.<byte[]>absent());
  } catch (InvalidMessageException | IOException e) {
    Log.w(TAG, e);
    throw new InvalidPartException(e);
  }
}