service_keepalive.h | Explore in Territory

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef SERVICES_SERVICE_MANAGER_PUBLIC_CPP_SERVICE_KEEPALIVE_H_
#define SERVICES_SERVICE_MANAGER_PUBLIC_CPP_SERVICE_KEEPALIVE_H_

#include <optional>

#include "base/component_export.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "base/observer_list_types.h"
#include "base/time/time.h"
#include "base/timer/timer.h"

namespace service_manager {

class ServiceReceiver;
class ServiceKeepaliveRef;

// Service implementations are responsible for managing their own lifetime and
// as such are expected to call |ServiceReceiver::RequestClose()| on their own
// ServiceReceiver when they are no longer in use by any clients and otherwise
// have no reason to keep running (e.g. no active UI visible).
//
// ServiceKeepalive helps Service implementations accomplish this by vending
// instances of ServiceKeepaliveRef (see |CreateRef()| below). Once any
// ServiceKeepaliveRef has been created by a ServiceKeepalive, the
// ServiceKeepalive begins keeping track of the number of existing
// ServiceKeepaliveRefs.
//
// If the ServiceKeepalive's number of living ServiceKeepaliveRef instances goes
// to zero, the service is considered idle. If the ServiceKeepalive is
// configured with an idle timeout, it will automatically invoke
// |ServiceReceiver::RequestClose()| on its associated ServiceReceiver once the
// service has remained idle for that continuous duration.
//
// Services can use this mechanism to vend ServiceKeepaliveRefs to various parts
// of their implementation (e.g. to individual bound interface implementations)
// in order to safely and cleanly distribute their lifetime control.
class COMPONENT_EXPORT(SERVICE_MANAGER_CPP) ServiceKeepalive { … };

// Objects which can be created by a |ServiceKeepalive| and cloned from each
// other. The ServiceReceiver referenced by a ServiceKeepalive is considered
// active as long as one of these objects exists and is associated with that
// ServiceKeepalive.
class COMPONENT_EXPORT(SERVICE_MANAGER_CPP) ServiceKeepaliveRef { … };

}  // namespace service_manager

#endif  // SERVICES_SERVICE_MANAGER_PUBLIC_CPP_SERVICE_KEEPALIVE_H_
chromium/services/service_manager/public/cpp/service_keepalive.h
