C++ Future::isDiscarded方法代码示例

/*
 * Class:     org_apache_mesos_state_ZooKeeperState
 * Method:    __names_cancel
 * Signature: (J)Z
 */
JNIEXPORT jboolean JNICALL Java_org_apache_mesos_state_ZooKeeperState__1_1names_1cancel
  (JNIEnv* env, jobject thiz, jlong jfuture)
{
  Future<vector<string> >* future = (Future<vector<string> >*) jfuture;

  if (!future->isDiscarded()) {
    future->discard();
    return (jboolean) future->isDiscarded();
  }

  return (jboolean) true;
}

void LeaderContenderProcess::cancelled(const Future<bool>& result)
{
  CHECK_READY(candidacy);
  LOG(INFO) << "Membership cancelled: " << candidacy->id();

  // Can be called as a result of either withdraw() or server side
  // expiration.
  CHECK(withdrawing.isSome() || watching.isSome());

  CHECK(!result.isDiscarded());

  if (result.isFailed()) {
    if (withdrawing.isSome()) {
      withdrawing.get()->fail(result.failure());
    }

    if (watching.isSome()) {
      watching.get()->fail(result.failure());
    }
  } else {
    if (withdrawing.isSome()) {
      withdrawing.get()->set(result);
    }

    if (watching.isSome()) {
      watching.get()->set(Nothing());
    }
  }
}

Future<bool> LeaderContenderProcess::withdraw()
{
  if (contending.isNone()) {
    // Nothing to withdraw because the contender has not contended.
    return false;
  }

  if (withdrawing.isSome()) {
    // Repeated calls to withdraw get the same result.
    return withdrawing.get();
  }

  withdrawing = new Promise<bool>();

  CHECK(!candidacy.isDiscarded());

  if (candidacy.isPending()) {
    // If we have not obtained the candidacy yet, we withdraw after
    // it is obtained.
    LOG(INFO) << "Withdraw requested before the candidacy is obtained; will "
              << "withdraw after it happens";
    candidacy.onAny(defer(self(), &Self::cancel));
  } else if (candidacy.isReady()) {
    cancel();
  } else {
    // We have failed to obtain the candidacy so we do not need to
    // cancel it.
    return false;
  }

  return withdrawing.get()->future();
}

/*
 * Class:     org_apache_mesos_state_AbstractState
 * Method:    __expunge_get
 * Signature: (J)Ljava/lang/Boolean;
 */
JNIEXPORT jobject JNICALL Java_org_apache_mesos_state_AbstractState__1_1expunge_1get
  (JNIEnv* env, jobject thiz, jlong jfuture)
{
  Future<bool>* future = (Future<bool>*) jfuture;

  future->await();

  if (future->isFailed()) {
    jclass clazz = env->FindClass("java/util/concurrent/ExecutionException");
    env->ThrowNew(clazz, future->failure().c_str());
    return NULL;
  } else if (future->isDiscarded()) {
    // TODO(benh): Consider throwing an ExecutionException since we
    // never return true for 'isCancelled'.
    jclass clazz = env->FindClass("java/util/concurrent/CancellationException");
    env->ThrowNew(clazz, "Future was discarded");
    return NULL;
  }

  CHECK_READY(*future);

  if (future->get()) {
    jclass clazz = env->FindClass("java/lang/Boolean");
    return env->GetStaticObjectField(
        clazz, env->GetStaticFieldID(clazz, "TRUE", "Ljava/lang/Boolean;"));
  }

  jclass clazz = env->FindClass("java/lang/Boolean");
  return env->GetStaticObjectField(
      clazz, env->GetStaticFieldID(clazz, "FALSE", "Ljava/lang/Boolean;"));
}

/*
 * Class:     org_apache_mesos_state_AbstractState
 * Method:    __fetch_get
 * Signature: (J)Lorg/apache/mesos/state/Variable;
 */
JNIEXPORT jobject JNICALL Java_org_apache_mesos_state_AbstractState__1_1fetch_1get
  (JNIEnv* env, jobject thiz, jlong jfuture)
{
  Future<Variable>* future = (Future<Variable>*) jfuture;

  future->await();

  if (future->isFailed()) {
    jclass clazz = env->FindClass("java/util/concurrent/ExecutionException");
    env->ThrowNew(clazz, future->failure().c_str());
    return nullptr;
  } else if (future->isDiscarded()) {
    // TODO(benh): Consider throwing an ExecutionException since we
    // never return true for 'isCancelled'.
    jclass clazz = env->FindClass("java/util/concurrent/CancellationException");
    env->ThrowNew(clazz, "Future was discarded");
    return nullptr;
  }

  CHECK_READY(*future);

  Variable* variable = new Variable(future->get());

  // Variable variable = new Variable();
  jclass clazz = env->FindClass("org/apache/mesos/state/Variable");

  jmethodID _init_ = env->GetMethodID(clazz, "<init>", "()V");
  jobject jvariable = env->NewObject(clazz, _init_);

  jfieldID __variable = env->GetFieldID(clazz, "__variable", "J");
  env->SetLongField(jvariable, __variable, (jlong) variable);

  return jvariable;
}

/*
 * Class:     org_apache_mesos_state_ZooKeeperState
 * Method:    __expunge_get
 * Signature: (J)Ljava/lang/Boolean;
 */
JNIEXPORT jobject JNICALL Java_org_apache_mesos_state_ZooKeeperState__1_1expunge_1get
  (JNIEnv* env, jobject thiz, jlong jfuture)
{
  Future<bool>* future = (Future<bool>*) jfuture;

  future->await();

  if (future->isFailed()) {
    jclass clazz = env->FindClass("java/util/concurrent/ExecutionException");
    env->ThrowNew(clazz, future->failure().c_str());
    return NULL;
  } else if (future->isDiscarded()) {
    jclass clazz = env->FindClass("java/util/concurrent/CancellationException");
    env->ThrowNew(clazz, "Future was discarded");
    return NULL;
  }

  CHECK(future->isReady());

  if (future->get()) {
    jclass clazz = env->FindClass("java/lang/Boolean");
    return env->GetStaticObjectField(
        clazz, env->GetStaticFieldID(clazz, "TRUE", "Ljava/lang/Boolean;"));
  }

  jclass clazz = env->FindClass("java/lang/Boolean");
  return env->GetStaticObjectField(
      clazz, env->GetStaticFieldID(clazz, "FALSE", "Ljava/lang/Boolean;"));
}

  void _healthCheck()
  {
    if (check.has_http()) {
      promise.fail("HTTP health check is not supported");
    } else if (check.has_command()) {
      const CommandInfo& command = check.command();

      map<string, string> environment;

      foreach (const Environment_Variable& variable,
               command.environment().variables()) {
        environment[variable.name()] = variable.value();
      }

      VLOG(2) << "Launching health command: " << command.value();

      Try<Subprocess> external =
        process::subprocess(
          command.value(),
          // Reading from STDIN instead of PIPE because scripts
          // seeing an open STDIN pipe might behave differently
          // and we do not expect to pass any value from STDIN
          // or PIPE.
          Subprocess::FD(STDIN_FILENO),
          Subprocess::FD(STDERR_FILENO),
          Subprocess::FD(STDERR_FILENO),
          environment);

      if (external.isError()) {
        promise.fail("Error creating subprocess for healthcheck");
      } else {
        Future<Option<int> > status = external.get().status();
        status.await(Seconds(check.timeout_seconds()));

        if (!status.isReady()) {
          string msg = "Shell command check failed with reason: ";
          if (status.isFailed()) {
            msg += "failed with error: " + status.failure();
          } else if (status.isDiscarded()) {
            msg += "status future discarded";
          } else {
            msg += "status still pending after timeout " +
                   stringify(Seconds(check.timeout_seconds()));
          }

          promise.fail(msg);
          return;
        }

        int statusCode = status.get().get();
        if (statusCode != 0) {
          string message = "Health command check " + WSTRINGIFY(statusCode);
          failure(message);
        } else {
          success();
        }
      }
    } else {

/*
 * Class:     org_apache_mesos_state_AbstractState
 * Method:    __names_get_timeout
 * Signature: (JJLjava/util/concurrent/TimeUnit;)Ljava/util/Iterator;
 */
JNIEXPORT jobject JNICALL Java_org_apache_mesos_state_AbstractState__1_1names_1get_1timeout
  (JNIEnv* env, jobject thiz, jlong jfuture, jlong jtimeout, jobject junit)
{
  Future<set<string> >* future = (Future<set<string> >*) jfuture;

  jclass clazz = env->GetObjectClass(junit);

  // long seconds = unit.toSeconds(time);
  jmethodID toSeconds = env->GetMethodID(clazz, "toSeconds", "(J)J");

  jlong jseconds = env->CallLongMethod(junit, toSeconds, jtimeout);

  Seconds seconds(jseconds);

  if (future->await(seconds)) {
    if (future->isFailed()) {
      clazz = env->FindClass("java/util/concurrent/ExecutionException");
      env->ThrowNew(clazz, future->failure().c_str());
      return NULL;
    } else if (future->isDiscarded()) {
      // TODO(benh): Consider throwing an ExecutionException since we
      // never return true for 'isCancelled'.
      clazz = env->FindClass("java/util/concurrent/CancellationException");
      env->ThrowNew(clazz, "Future was discarded");
      return NULL;
    }

    CHECK_READY(*future);

    // List names = new ArrayList();
    clazz = env->FindClass("java/util/ArrayList");

    jmethodID _init_ = env->GetMethodID(clazz, "<init>", "()V");
    jobject jnames = env->NewObject(clazz, _init_);

    jmethodID add = env->GetMethodID(clazz, "add", "(Ljava/lang/Object;)Z");

    foreach (const string& name, future->get()) {
      jobject jname = convert<string>(env, name);
      env->CallBooleanMethod(jnames, add, jname);
    }

    // Iterator iterator = jnames.iterator();
    jmethodID iterator =
      env->GetMethodID(clazz, "iterator", "()Ljava/util/Iterator;");
    jobject jiterator = env->CallObjectMethod(jnames, iterator);

    return jiterator;
  }

  clazz = env->FindClass("java/util/concurrent/TimeoutException");
  env->ThrowNew(clazz, "Failed to wait for future within timeout");

  return NULL;
}

void LeaderDetectorProcess::watched(Future<set<Group::Membership> > memberships)
{
  CHECK(!memberships.isDiscarded());

  if (memberships.isFailed()) {
    LOG(ERROR) << "Failed to watch memberships: " << memberships.failure();
    leader = None();
    foreach (Promise<Option<Group::Membership> >* promise, promises) {
      promise->fail(memberships.failure());
      delete promise;
    }

void LeaderDetectorProcess::watched(const Future<set<Group::Membership> >& memberships)
{
  CHECK(!memberships.isDiscarded());

  if (memberships.isFailed()) {
    LOG(ERROR) << "Failed to watch memberships: " << memberships.failure();

    // Setting this error stops the watch loop and the detector
    // transitions to an erroneous state. Further calls to detect()
    // will directly fail as a result.
    error = Error(memberships.failure());
    leader = None();
    foreach (Promise<Option<Group::Membership> >* promise, promises) {
      promise->fail(memberships.failure());
      delete promise;
    }

// See the comment below as to why subprocess is passed to cleanup.
inline void cleanup(
    const Future<Option<int> >& result,
    Promise<Option<int> >* promise,
    const Subprocess& subprocess)
{
  CHECK(!result.isPending());
  CHECK(!result.isDiscarded());

  if (result.isFailed()) {
    promise->fail(result.failure());
  } else {
    promise->set(result.get());
  }

  delete promise;
}

 void waited(const Future<T>& future)
 {
     if (future.isFailed()) {
         promise->fail("Collect failed: " + future.failure());
         terminate(this);
     } else if (future.isDiscarded()) {
         promise->fail("Collect failed: future discarded");
         terminate(this);
     } else {
         assert(future.isReady());
         values.push_back(future.get());
         if (futures.size() == values.size()) {
             promise->set(values);
             terminate(this);
         }
     }
 }

/*
 * Class:     org_apache_mesos_state_ZooKeeperState
 * Method:    __fetch_get_timeout
 * Signature: (JJLjava/util/concurrent/TimeUnit;)Lorg/apache/mesos/state/Variable;
 */
JNIEXPORT jobject JNICALL Java_org_apache_mesos_state_ZooKeeperState__1_1fetch_1get_1timeout
  (JNIEnv* env, jobject thiz, jlong jfuture, jlong jtimeout, jobject junit)
{
  Future<Variable>* future = (Future<Variable>*) jfuture;

  jclass clazz = env->GetObjectClass(junit);

  // long seconds = unit.toSeconds(time);
  jmethodID toSeconds = env->GetMethodID(clazz, "toSeconds", "(J)J");

  jlong jseconds = env->CallLongMethod(junit, toSeconds, jtimeout);

  Seconds seconds(jseconds);

  if (future->await(seconds)) {
    if (future->isFailed()) {
      clazz = env->FindClass("java/util/concurrent/ExecutionException");
      env->ThrowNew(clazz, future->failure().c_str());
      return NULL;
    } else if (future->isDiscarded()) {
      clazz = env->FindClass("java/util/concurrent/CancellationException");
      env->ThrowNew(clazz, "Future was discarded");
      return NULL;
    }

    CHECK(future->isReady());
    Variable* variable = new Variable(future->get());

    // Variable variable = new Variable();
    clazz = env->FindClass("org/apache/mesos/state/Variable");

    jmethodID _init_ = env->GetMethodID(clazz, "<init>", "()V");
    jobject jvariable = env->NewObject(clazz, _init_);

    jfieldID __variable = env->GetFieldID(clazz, "__variable", "J");
    env->SetLongField(jvariable, __variable, (jlong) variable);

    return jvariable;
  }

  clazz = env->FindClass("java/util/concurrent/TimeoutException");
  env->ThrowNew(clazz, "Failed to wait for future within timeout");

  return NULL;
}

  void _read(const Pipe::Reader& reader, const Future<Result<Event>>& event)
  {
    CHECK(!event.isDiscarded());

    // Ignore enqueued events from the previous Subscribe call reader.
    if (subscribed.isNone() || subscribed->reader != reader) {
      VLOG(1) << "Ignoring event from old stale connection";
      return;
    }

    CHECK_EQ(SUBSCRIBED, state);
    CHECK_SOME(connectionId);

    // This could happen if the agent process died while sending a response.
    if (event.isFailed()) {
      LOG(ERROR) << "Failed to decode the stream of events: "
                 << event.failure();

      disconnected(connectionId.get(), event.failure());
      return;
    }

    // This could happen if the agent failed over after sending an event.
    if (event->isNone()) {
      const string error =  "End-Of-File received from agent. The agent closed "
                            "the event stream";
      LOG(ERROR) << error;

      disconnected(connectionId.get(), error);
      return;
    }

    if (event->isError()) {
      error("Failed to de-serialize event: " + event->error());
      return;
    }

    receive(event.get().get(), false);
    read();
  }

void LeaderContenderProcess::joined()
{
  CHECK(!candidacy.isDiscarded());

  // Cannot be watching because the candidacy is not obtained yet.
  CHECK_NONE(watching);

  CHECK_SOME(contending);

  if (candidacy.isFailed()) {
    // The promise 'withdrawing' will be set to false in cancel().
    contending.get()->fail(candidacy.failure());
    return;
  }

  if (withdrawing.isSome()) {
    LOG(INFO) << "Joined group after the contender started withdrawing";

    // The promise 'withdrawing' will be set to 'false' in subsequent
    // 'cancel()' call.
    return;
  }

  LOG(INFO) << "New candidate (id='" << candidacy->id()
            << "') has entered the contest for leadership";

  // Transition to 'watching' state.
  watching = new Promise<Nothing>();

  // Notify the client.
  if (contending.get()->set(watching.get()->future())) {
    // Continue to watch that our membership is not removed (if the
    // client still cares about it).
    candidacy->cancelled()
      .onAny(defer(self(), &Self::cancelled, lambda::_1));
  }
}