foundationdb/flow/ActorCollection.h

66 lines
2.7 KiB
C++

/*
* ActorCollection.h
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
*
* 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.
*/
#ifndef FDBSERVER_ACTORCOLLECTION_H
#define FDBSERVER_ACTORCOLLECTION_H
#pragma once
#include "flow/flow.h"
// actorCollection
// - Can add a future at any time
// - Cancels all futures in deterministic order if cancelled
// - Throws an error immediately if any future throws an error
// - Never returns otherwise, unless returnWhenEmptied=true in which case returns the first time it goes from count 1 to count 0 futures
// - Uses memory proportional to the number of unready futures added (i.e. memory
// is freed promptly when an actor in the collection returns)
Future<Void> actorCollection( FutureStream<Future<Void>> const& addActor, int* const& optionalCountPtr = NULL, double* const& lastChangeTime = NULL, double* const& idleTime = NULL, double* const& allTime = NULL, bool const& returnWhenEmptied=false );
// ActorCollectionNoErrors is an easy-to-use wrapper for actorCollection() when you know that no errors will
// be thrown by the actors (e.g. because they are wrapped with individual error reporters).
struct ActorCollectionNoErrors : NonCopyable {
private:
Future<Void> m_ac;
PromiseStream<Future<Void>> m_add;
int m_size;
void init() { m_size = 0; m_ac = actorCollection(m_add.getFuture(), &m_size); }
public:
ActorCollectionNoErrors() { init(); }
void clear() { m_ac=Future<Void>(); init(); }
void add( Future<Void> actor ) { m_add.send(actor); }
int size() const { return m_size; }
};
// Easy-to-use wrapper that permits getting the result (error or returnWhenEmptied) from actorCollection
class ActorCollection : NonCopyable {
PromiseStream<Future<Void>> m_add;
Future<Void> m_out;
public:
explicit ActorCollection( bool returnWhenEmptied ) {
m_out = actorCollection(m_add.getFuture(), NULL, NULL, NULL, NULL, returnWhenEmptied );
}
void add( Future<Void> a ) { m_add.send(a); }
Future<Void> getResult() { return m_out; }
void clear( bool returnWhenEmptied ) { m_out.cancel(); m_out = actorCollection(m_add.getFuture(), NULL, NULL, NULL, NULL, returnWhenEmptied ); }
};
#endif