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/*
* Copyright (C) 2018 The Android Open Source Project
*
* 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.
*/
#pragma once
#include <functional>
#include <android/hidl/base/1.0/IBase.h>
#include <utils/RefBase.h>
#include <utils/StrongPointer.h>
namespace android {
namespace hardware {
namespace details {
class LazyServiceRegistrarImpl;
} // namespace details
/**
* Exits when all HALs registered through this object have 0 clients
*
* In order to use this class, it's expected that your service:
* - registers all services in the process with this API
* - configures services as oneshot + disabled in init .rc files
* - uses 'interface' declarations in init .rc files
*
* For more information on init .rc configuration, see system/core/init/README.md
**/
class LazyServiceRegistrar {
public:
static LazyServiceRegistrar& getInstance();
status_t registerService(const sp<::android::hidl::base::V1_0::IBase>& service,
const std::string& name = "default");
/**
* Set a callback that is invoked when the active HAL count (i.e. HALs with clients)
* registered with this process drops to zero (or becomes nonzero).
* The callback takes a boolean argument, which is 'true' if there is
* at least one HAL with clients.
*
* Callback return value:
* - false: Default behavior for lazy HALs (shut down the process if there
* are no clients).
* - true: Don't shut down the process even if there are no clients.
*
* This callback gives a chance to:
* 1 - Perform some additional operations before exiting;
* 2 - Prevent the process from exiting by returning "true" from the
* callback.
*
* This method should be called before 'registerService' to avoid races.
*/
void setActiveServicesCallback(const std::function<bool(bool)>& activeServicesCallback);
/**
* Try to unregister all services previously registered with 'registerService'.
* Returns 'true' if successful. This should only be called within
* the callback registered by setActiveServicesCallback.
*/
bool tryUnregister();
/**
* Re-register services that were unregistered by 'tryUnregister'.
* This method should be called in the case 'tryUnregister' fails
* (and should be called on the same thread).
*/
void reRegister();
private:
std::shared_ptr<details::LazyServiceRegistrarImpl> mImpl;
LazyServiceRegistrar();
};
} // namespace hardware
} // namespace android