android/utils/battery_listener.cpp

/*
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#include "battery_listener.h"
#ifdef LOG_TAG
#undef LOG_TAG
#endif
#define LOG_TAG "LocSvc_BatteryListener"
#define LOG_NDEBUG 0

#include <android/hidl/manager/1.0/IServiceManager.h>
#include <android/hardware/health/2.1/IHealth.h>
#include <android/hardware/health/2.1/IHealthInfoCallback.h>
#include <healthhalutils/HealthHalUtils.h>
#include <hidl/HidlTransportSupport.h>
#include <thread>
#include <log_util.h>

using android::hardware::interfacesEqual;
using android::hardware::Return;
using android::hardware::Void;
using android::hardware::health::V1_0::BatteryStatus;
using android::hardware::health::V1_0::toString;
using android::hardware::health::V2_0::get_health_service;
using android::hardware::health::V2_1::HealthInfo;
using android::hardware::health::V2_1::IHealthInfoCallback;
using android::hardware::health::V2_1::IHealth;
using android::hardware::health::V2_0::Result;
using android::hidl::manager::V1_0::IServiceManager;
using namespace std::literals::chrono_literals;

static bool sIsBatteryListened = false;
namespace android {

#define GET_HEALTH_SVC_RETRY_CNT 5
#define GET_HEALTH_SVC_WAIT_TIME_MS 500

struct BatteryListenerImpl : public hardware::health::V2_1::IHealthInfoCallback,
                             public hardware::hidl_death_recipient {
    typedef std::function<void(bool)> cb_fn_t;
    BatteryListenerImpl(cb_fn_t cb);
    virtual ~BatteryListenerImpl ();
    virtual hardware::Return<void> healthInfoChanged(
            const hardware::health::V2_0::HealthInfo& info);
    virtual hardware::Return<void> healthInfoChanged_2_1(
            const hardware::health::V2_1::HealthInfo& info);
    virtual void serviceDied(uint64_t cookie,
                             const wp<hidl::base::V1_0::IBase>& who);
    bool isCharging() {
        std::lock_guard<std::mutex> _l(mLock);
        return statusToBool(mStatus);
    }
  private:
    sp<hardware::health::V2_1::IHealth> mHealth;
    status_t init();
    BatteryStatus mStatus;
    cb_fn_t mCb;
    std::mutex mLock;
    std::condition_variable mCond;
    std::unique_ptr<std::thread> mThread;
    bool mDone;
    bool statusToBool(const BatteryStatus &s) const {
        return (s == BatteryStatus::CHARGING) ||
               (s ==  BatteryStatus::FULL);
    }
};

status_t BatteryListenerImpl::init()
{
    int tries = 0;

    if (mHealth != NULL)
        return INVALID_OPERATION;

    do {
        mHealth = IHealth::getService("default", true);
        if (mHealth != NULL)
            break;
        usleep(GET_HEALTH_SVC_WAIT_TIME_MS * 1000);
        tries++;
    } while(tries < GET_HEALTH_SVC_RETRY_CNT);

    if (mHealth == NULL) {
        LOC_LOGe("no health service found, retries %d", tries);
        return NO_INIT;
    } else {
        LOC_LOGi("Get health service in %d tries", tries);
    }
    mStatus = BatteryStatus::UNKNOWN;
    auto ret = mHealth->getChargeStatus([&](Result r, BatteryStatus status) {
        if (r != Result::SUCCESS) {
            LOC_LOGe("batterylistener: cannot get battery status");
            return;
        }
        mStatus = status;
    });
    if (!ret.isOk()) {
        LOC_LOGe("batterylistener: get charge status transaction error");
    }
    if (mStatus == BatteryStatus::UNKNOWN) {
        LOC_LOGw("batterylistener: init: invalid battery status");
    }
    mDone = false;
    mThread = std::make_unique<std::thread>([this]() {
            std::unique_lock<std::mutex> l(mLock);
            BatteryStatus local_status = mStatus;
            while (!mDone) {
                if (local_status == mStatus) {
                    mCond.wait(l);
                    continue;
                }
                local_status = mStatus;
                switch (local_status) {
                    // NOT_CHARGING is a special event that indicates, a battery is connected,
                    // but not charging. This is seen for approx a second
                    // after charger is plugged in. A charging event is eventually received.
                    // We must try to avoid an unnecessary cb to HAL
                    // only to call it again shortly.
                    // An option to deal with this transient event would be to ignore this.
                    // Or process this event with a slight delay (i.e cancel this event
                    // if a different event comes in within a timeout
                    case BatteryStatus::NOT_CHARGING : {
                        auto mStatusnot_ncharging =
                                [this, local_status]() { return mStatus != local_status; };
                        mCond.wait_for(l, 3s, mStatusnot_ncharging);
                        if (mStatusnot_ncharging()) // i.e event changed
                            break;
                        [[clang::fallthrough]]; //explicit fall-through between switch labels
                    }
                    default:
                        bool c = statusToBool(local_status);
                        LOC_LOGi("healthInfo cb thread: cb %s", c ? "CHARGING" : "NOT CHARGING");
                        l.unlock();
                        mCb(c);
                        l.lock();
                        break;
                }
            }
    });
    auto reg = mHealth->registerCallback(this);
    if (!reg.isOk()) {
        LOC_LOGe("Transaction error in registeringCb to HealthHAL death: %s",
                reg.description().c_str());
    }

    auto linked = mHealth->linkToDeath(this, 0 /* cookie */);
    if (!linked.isOk() || linked == false) {
        LOC_LOGe("Transaction error in linking to HealthHAL death: %s",
                linked.description().c_str());
    }
    return NO_ERROR;
}

BatteryListenerImpl::BatteryListenerImpl(cb_fn_t cb) :
        mCb(cb)
{
    init();
}

BatteryListenerImpl::~BatteryListenerImpl()
{
    {
        std::lock_guard<std::mutex> _l(mLock);
        if (mHealth != NULL)
            mHealth->unregisterCallback(this);
            auto r = mHealth->unlinkToDeath(this);
            if (!r.isOk() || r == false) {
                LOC_LOGe("Transaction error in unregister to HealthHAL death: %s",
                        r.description().c_str());
            }
    }
    mDone = true;
    mThread->join();
}

void BatteryListenerImpl::serviceDied(uint64_t cookie __unused,
                                     const wp<hidl::base::V1_0::IBase>& who)
{
    {
        std::lock_guard<std::mutex> _l(mLock);
        if (mHealth == NULL || !interfacesEqual(mHealth, who.promote())) {
            LOC_LOGe("health not initialized or unknown interface died");
            return;
        }
        LOC_LOGi("health service died, reinit");
        mDone = true;
    }
    mHealth = NULL;
    mCond.notify_one();
    mThread->join();
    std::lock_guard<std::mutex> _l(mLock);
    init();
}

// this callback seems to be a SYNC callback and so
// waits for return before next event is issued.
// therefore we need not have a queue to process
// NOT_CHARGING and CHARGING concurrencies.
// Replace single var by a list if this assumption is broken
Return<void> BatteryListenerImpl::healthInfoChanged(
        const hardware::health::V2_0::HealthInfo& info) {
    LOC_LOGv("healthInfoChanged: %d", info.legacy.batteryStatus);
    std::unique_lock<std::mutex> l(mLock);
    if (info.legacy.batteryStatus != mStatus) {
        mStatus = info.legacy.batteryStatus;
        mCond.notify_one();
    }
    return Void();
}

Return<void> BatteryListenerImpl::healthInfoChanged_2_1(
        const hardware::health::V2_1::HealthInfo& info) {
    LOC_LOGv("healthInfoChanged_2_1: %d", info.legacy.legacy.batteryStatus);
    healthInfoChanged(info.legacy);
    return Void();
}

static sp<BatteryListenerImpl> batteryListener;

bool batteryPropertiesListenerIsCharging() {
    return batteryListener->isCharging();
}

status_t batteryPropertiesListenerInit(BatteryListenerImpl::cb_fn_t cb) {
    batteryListener = new BatteryListenerImpl(cb);
    bool isCharging = batteryPropertiesListenerIsCharging();
    LOC_LOGv("charging status: %s charging", isCharging ? "" : "not");;
    if (isCharging) {
        cb(isCharging);
    }
    return NO_ERROR;
}

status_t batteryPropertiesListenerDeinit() {
    batteryListener.clear();
    return OK;
}

} // namespace android

void loc_extn_battery_properties_listener_init(battery_status_change_fn_t fn) {
    if (!sIsBatteryListened) {
        std::thread t1(android::batteryPropertiesListenerInit,
                [=](bool charging) { fn(charging); });
        t1.detach();
        sIsBatteryListened = true;
    }
}

void loc_extn_battery_properties_listener_deinit() {
    android::batteryPropertiesListenerDeinit();
}

bool loc_extn_battery_properties_is_charging() {
    return android::batteryPropertiesListenerIsCharging();
}