SensorService.cpp revision ac9a96da65f6eae4513654adaad8a457d1c1575c 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <stdint.h>
18#include <math.h>
19#include <sys/types.h>
20
21#include <cutils/properties.h>
22
23#include <utils/SortedVector.h>
24#include <utils/KeyedVector.h>
25#include <utils/threads.h>
26#include <utils/Atomic.h>
27#include <utils/Errors.h>
28#include <utils/RefBase.h>
29#include <utils/Singleton.h>
30#include <utils/String16.h>
31
32#include <binder/BinderService.h>
33#include <binder/IServiceManager.h>
34#include <binder/PermissionCache.h>
35
36#include <gui/ISensorServer.h>
37#include <gui/ISensorEventConnection.h>
38#include <gui/SensorEventQueue.h>
39
40#include <hardware/sensors.h>
41#include <hardware_legacy/power.h>
42
43#include "BatteryService.h"
44#include "CorrectedGyroSensor.h"
45#include "GravitySensor.h"
46#include "LinearAccelerationSensor.h"
47#include "OrientationSensor.h"
48#include "RotationVectorSensor.h"
49#include "SensorFusion.h"
50#include "SensorService.h"
51
52namespace android {
53// ---------------------------------------------------------------------------
54
55/*
56 * Notes:
57 *
58 * - what about a gyro-corrected magnetic-field sensor?
59 * - run mag sensor from time to time to force calibration
60 * - gravity sensor length is wrong (=> drift in linear-acc sensor)
61 *
62 */
63
64const char* SensorService::WAKE_LOCK_NAME = "SensorService";
65
66SensorService::SensorService()
67    : mInitCheck(NO_INIT)
68{
69}
70
71void SensorService::onFirstRef()
72{
73    ALOGD("nuSensorService starting...");
74
75    SensorDevice& dev(SensorDevice::getInstance());
76
77    if (dev.initCheck() == NO_ERROR) {
78        sensor_t const* list;
79        ssize_t count = dev.getSensorList(&list);
80        if (count > 0) {
81            ssize_t orientationIndex = -1;
82            bool hasGyro = false;
83            uint32_t virtualSensorsNeeds =
84                    (1<<SENSOR_TYPE_GRAVITY) |
85                    (1<<SENSOR_TYPE_LINEAR_ACCELERATION) |
86                    (1<<SENSOR_TYPE_ROTATION_VECTOR);
87
88            mLastEventSeen.setCapacity(count);
89            for (ssize_t i=0 ; i<count ; i++) {
90                registerSensor( new HardwareSensor(list[i]) );
91                switch (list[i].type) {
92                    case SENSOR_TYPE_ORIENTATION:
93                        orientationIndex = i;
94                        break;
95                    case SENSOR_TYPE_GYROSCOPE:
96                        hasGyro = true;
97                        break;
98                    case SENSOR_TYPE_GRAVITY:
99                    case SENSOR_TYPE_LINEAR_ACCELERATION:
100                    case SENSOR_TYPE_ROTATION_VECTOR:
101                        virtualSensorsNeeds &= ~(1<<list[i].type);
102                        break;
103                }
104            }
105
106            // it's safe to instantiate the SensorFusion object here
107            // (it wants to be instantiated after h/w sensors have been
108            // registered)
109            const SensorFusion& fusion(SensorFusion::getInstance());
110
111            if (hasGyro) {
112                // Always instantiate Android's virtual sensors. Since they are
113                // instantiated behind sensors from the HAL, they won't
114                // interfere with applications, unless they looks specifically
115                // for them (by name).
116
117                registerVirtualSensor( new RotationVectorSensor() );
118                registerVirtualSensor( new GravitySensor(list, count) );
119                registerVirtualSensor( new LinearAccelerationSensor(list, count) );
120
121                // these are optional
122                registerVirtualSensor( new OrientationSensor() );
123                registerVirtualSensor( new CorrectedGyroSensor(list, count) );
124            }
125
126            // build the sensor list returned to users
127            mUserSensorList = mSensorList;
128
129            if (hasGyro) {
130                // virtual debugging sensors are not added to mUserSensorList
131                registerVirtualSensor( new GyroDriftSensor() );
132            }
133
134            if (hasGyro &&
135                    (virtualSensorsNeeds & (1<<SENSOR_TYPE_ROTATION_VECTOR))) {
136                // if we have the fancy sensor fusion, and it's not provided by the
137                // HAL, use our own (fused) orientation sensor by removing the
138                // HAL supplied one form the user list.
139                if (orientationIndex >= 0) {
140                    mUserSensorList.removeItemsAt(orientationIndex);
141                }
142            }
143
144            // debugging sensor list
145            for (size_t i=0 ; i<mSensorList.size() ; i++) {
146                switch (mSensorList[i].getType()) {
147                    case SENSOR_TYPE_GRAVITY:
148                    case SENSOR_TYPE_LINEAR_ACCELERATION:
149                    case SENSOR_TYPE_ROTATION_VECTOR:
150                        if (strstr(mSensorList[i].getVendor().string(), "Google")) {
151                            mUserSensorListDebug.add(mSensorList[i]);
152                        }
153                        break;
154                    default:
155                        mUserSensorListDebug.add(mSensorList[i]);
156                        break;
157                }
158            }
159
160            run("SensorService", PRIORITY_URGENT_DISPLAY);
161            mInitCheck = NO_ERROR;
162        }
163    }
164}
165
166void SensorService::registerSensor(SensorInterface* s)
167{
168    sensors_event_t event;
169    memset(&event, 0, sizeof(event));
170
171    const Sensor sensor(s->getSensor());
172    // add to the sensor list (returned to clients)
173    mSensorList.add(sensor);
174    // add to our handle->SensorInterface mapping
175    mSensorMap.add(sensor.getHandle(), s);
176    // create an entry in the mLastEventSeen array
177    mLastEventSeen.add(sensor.getHandle(), event);
178}
179
180void SensorService::registerVirtualSensor(SensorInterface* s)
181{
182    registerSensor(s);
183    mVirtualSensorList.add( s );
184}
185
186SensorService::~SensorService()
187{
188    for (size_t i=0 ; i<mSensorMap.size() ; i++)
189        delete mSensorMap.valueAt(i);
190}
191
192static const String16 sDump("android.permission.DUMP");
193
194status_t SensorService::dump(int fd, const Vector<String16>& args)
195{
196    const size_t SIZE = 1024;
197    char buffer[SIZE];
198    String8 result;
199    if (!PermissionCache::checkCallingPermission(sDump)) {
200        snprintf(buffer, SIZE, "Permission Denial: "
201                "can't dump SurfaceFlinger from pid=%d, uid=%d\n",
202                IPCThreadState::self()->getCallingPid(),
203                IPCThreadState::self()->getCallingUid());
204        result.append(buffer);
205    } else {
206        Mutex::Autolock _l(mLock);
207        snprintf(buffer, SIZE, "Sensor List:\n");
208        result.append(buffer);
209        for (size_t i=0 ; i<mSensorList.size() ; i++) {
210            const Sensor& s(mSensorList[i]);
211            const sensors_event_t& e(mLastEventSeen.valueFor(s.getHandle()));
212            snprintf(buffer, SIZE,
213                    "%-48s| %-32s | 0x%08x | maxRate=%7.2fHz | "
214                    "last=<%5.1f,%5.1f,%5.1f>\n",
215                    s.getName().string(),
216                    s.getVendor().string(),
217                    s.getHandle(),
218                    s.getMinDelay() ? (1000000.0f / s.getMinDelay()) : 0.0f,
219                    e.data[0], e.data[1], e.data[2]);
220            result.append(buffer);
221        }
222        SensorFusion::getInstance().dump(result, buffer, SIZE);
223        SensorDevice::getInstance().dump(result, buffer, SIZE);
224
225        snprintf(buffer, SIZE, "%d active connections\n",
226                mActiveConnections.size());
227        result.append(buffer);
228        snprintf(buffer, SIZE, "Active sensors:\n");
229        result.append(buffer);
230        for (size_t i=0 ; i<mActiveSensors.size() ; i++) {
231            int handle = mActiveSensors.keyAt(i);
232            snprintf(buffer, SIZE, "%s (handle=0x%08x, connections=%d)\n",
233                    getSensorName(handle).string(),
234                    handle,
235                    mActiveSensors.valueAt(i)->getNumConnections());
236            result.append(buffer);
237        }
238    }
239    write(fd, result.string(), result.size());
240    return NO_ERROR;
241}
242
243void SensorService::cleanupAutoDisabledSensor(const sp<SensorEventConnection>& connection,
244        sensors_event_t const* buffer, const int count) {
245    SensorInterface* sensor;
246    status_t err = NO_ERROR;
247    for (int i=0 ; i<count ; i++) {
248        int handle = buffer[i].sensor;
249        if (getSensorType(handle) == SENSOR_TYPE_SIGNIFICANT_MOTION) {
250            if (connection->hasSensor(handle)) {
251                sensor = mSensorMap.valueFor(handle);
252                if (sensor != NULL) {
253                    sensor->autoDisable(connection.get(), handle);
254                }
255                cleanupWithoutDisable(connection, handle);
256            }
257        }
258    }
259}
260
261bool SensorService::threadLoop()
262{
263    ALOGD("nuSensorService thread starting...");
264
265    const size_t numEventMax = 16;
266    const size_t minBufferSize = numEventMax + numEventMax * mVirtualSensorList.size();
267    sensors_event_t buffer[minBufferSize];
268    sensors_event_t scratch[minBufferSize];
269    SensorDevice& device(SensorDevice::getInstance());
270    const size_t vcount = mVirtualSensorList.size();
271
272    ssize_t count;
273    bool wakeLockAcquired = false;
274    const int halVersion = device.getHalDeviceVersion();
275    do {
276        count = device.poll(buffer, numEventMax);
277        if (count<0) {
278            ALOGE("sensor poll failed (%s)", strerror(-count));
279            break;
280        }
281
282        // Poll has returned. Hold a wakelock.
283        // Todo(): add a flag to the sensors definitions to indicate
284        // the sensors which can wake up the AP
285        for (int i = 0; i < count; i++) {
286            if (getSensorType(buffer[i].sensor) == SENSOR_TYPE_SIGNIFICANT_MOTION) {
287                 acquire_wake_lock(PARTIAL_WAKE_LOCK, WAKE_LOCK_NAME);
288                 wakeLockAcquired = true;
289                 break;
290            }
291        }
292
293        recordLastValue(buffer, count);
294
295        // handle virtual sensors
296        if (count && vcount) {
297            sensors_event_t const * const event = buffer;
298            const DefaultKeyedVector<int, SensorInterface*> virtualSensors(
299                    getActiveVirtualSensors());
300            const size_t activeVirtualSensorCount = virtualSensors.size();
301            if (activeVirtualSensorCount) {
302                size_t k = 0;
303                SensorFusion& fusion(SensorFusion::getInstance());
304                if (fusion.isEnabled()) {
305                    for (size_t i=0 ; i<size_t(count) ; i++) {
306                        fusion.process(event[i]);
307                    }
308                }
309                for (size_t i=0 ; i<size_t(count) && k<minBufferSize ; i++) {
310                    for (size_t j=0 ; j<activeVirtualSensorCount ; j++) {
311                        if (count + k >= minBufferSize) {
312                            ALOGE("buffer too small to hold all events: "
313                                    "count=%u, k=%u, size=%u",
314                                    count, k, minBufferSize);
315                            break;
316                        }
317                        sensors_event_t out;
318                        SensorInterface* si = virtualSensors.valueAt(j);
319                        if (si->process(&out, event[i])) {
320                            buffer[count + k] = out;
321                            k++;
322                        }
323                    }
324                }
325                if (k) {
326                    // record the last synthesized values
327                    recordLastValue(&buffer[count], k);
328                    count += k;
329                    // sort the buffer by time-stamps
330                    sortEventBuffer(buffer, count);
331                }
332            }
333        }
334
335        // handle backward compatibility for RotationVector sensor
336        if (halVersion < SENSORS_DEVICE_API_VERSION_1_0) {
337            for (int i = 0; i < count; i++) {
338                if (getSensorType(buffer[i].sensor) == SENSOR_TYPE_ROTATION_VECTOR) {
339                    // All the 4 components of the quaternion should be available
340                    // No heading accuracy. Set it to -1
341                    buffer[i].data[4] = -1;
342                }
343            }
344        }
345
346        // send our events to clients...
347        const SortedVector< wp<SensorEventConnection> > activeConnections(
348                getActiveConnections());
349        size_t numConnections = activeConnections.size();
350        for (size_t i=0 ; i<numConnections ; i++) {
351            sp<SensorEventConnection> connection(
352                    activeConnections[i].promote());
353            if (connection != 0) {
354                connection->sendEvents(buffer, count, scratch);
355                // Some sensors need to be auto disabled after the trigger
356                cleanupAutoDisabledSensor(connection, buffer, count);
357            }
358        }
359
360        // We have read the data, upper layers should hold the wakelock.
361        if (wakeLockAcquired) release_wake_lock(WAKE_LOCK_NAME);
362
363    } while (count >= 0 || Thread::exitPending());
364
365    ALOGW("Exiting SensorService::threadLoop => aborting...");
366    abort();
367    return false;
368}
369
370void SensorService::recordLastValue(
371        sensors_event_t const * buffer, size_t count)
372{
373    Mutex::Autolock _l(mLock);
374
375    // record the last event for each sensor
376    int32_t prev = buffer[0].sensor;
377    for (size_t i=1 ; i<count ; i++) {
378        // record the last event of each sensor type in this buffer
379        int32_t curr = buffer[i].sensor;
380        if (curr != prev) {
381            mLastEventSeen.editValueFor(prev) = buffer[i-1];
382            prev = curr;
383        }
384    }
385    mLastEventSeen.editValueFor(prev) = buffer[count-1];
386}
387
388void SensorService::sortEventBuffer(sensors_event_t* buffer, size_t count)
389{
390    struct compar {
391        static int cmp(void const* lhs, void const* rhs) {
392            sensors_event_t const* l = static_cast<sensors_event_t const*>(lhs);
393            sensors_event_t const* r = static_cast<sensors_event_t const*>(rhs);
394            return l->timestamp - r->timestamp;
395        }
396    };
397    qsort(buffer, count, sizeof(sensors_event_t), compar::cmp);
398}
399
400SortedVector< wp<SensorService::SensorEventConnection> >
401SensorService::getActiveConnections() const
402{
403    Mutex::Autolock _l(mLock);
404    return mActiveConnections;
405}
406
407DefaultKeyedVector<int, SensorInterface*>
408SensorService::getActiveVirtualSensors() const
409{
410    Mutex::Autolock _l(mLock);
411    return mActiveVirtualSensors;
412}
413
414String8 SensorService::getSensorName(int handle) const {
415    size_t count = mUserSensorList.size();
416    for (size_t i=0 ; i<count ; i++) {
417        const Sensor& sensor(mUserSensorList[i]);
418        if (sensor.getHandle() == handle) {
419            return sensor.getName();
420        }
421    }
422    String8 result("unknown");
423    return result;
424}
425
426int SensorService::getSensorType(int handle) const {
427    size_t count = mUserSensorList.size();
428    for (size_t i=0 ; i<count ; i++) {
429        const Sensor& sensor(mUserSensorList[i]);
430        if (sensor.getHandle() == handle) {
431            return sensor.getType();
432        }
433    }
434    return -1;
435}
436
437
438Vector<Sensor> SensorService::getSensorList()
439{
440    char value[PROPERTY_VALUE_MAX];
441    property_get("debug.sensors", value, "0");
442    if (atoi(value)) {
443        return mUserSensorListDebug;
444    }
445    return mUserSensorList;
446}
447
448sp<ISensorEventConnection> SensorService::createSensorEventConnection()
449{
450    uid_t uid = IPCThreadState::self()->getCallingUid();
451    sp<SensorEventConnection> result(new SensorEventConnection(this, uid));
452    return result;
453}
454
455void SensorService::cleanupConnection(SensorEventConnection* c)
456{
457    Mutex::Autolock _l(mLock);
458    const wp<SensorEventConnection> connection(c);
459    size_t size = mActiveSensors.size();
460    ALOGD_IF(DEBUG_CONNECTIONS, "%d active sensors", size);
461    for (size_t i=0 ; i<size ; ) {
462        int handle = mActiveSensors.keyAt(i);
463        if (c->hasSensor(handle)) {
464            ALOGD_IF(DEBUG_CONNECTIONS, "%i: disabling handle=0x%08x", i, handle);
465            SensorInterface* sensor = mSensorMap.valueFor( handle );
466            ALOGE_IF(!sensor, "mSensorMap[handle=0x%08x] is null!", handle);
467            if (sensor) {
468                sensor->activate(c, false);
469            }
470        }
471        SensorRecord* rec = mActiveSensors.valueAt(i);
472        ALOGE_IF(!rec, "mActiveSensors[%d] is null (handle=0x%08x)!", i, handle);
473        ALOGD_IF(DEBUG_CONNECTIONS,
474                "removing connection %p for sensor[%d].handle=0x%08x",
475                c, i, handle);
476
477        if (rec && rec->removeConnection(connection)) {
478            ALOGD_IF(DEBUG_CONNECTIONS, "... and it was the last connection");
479            mActiveSensors.removeItemsAt(i, 1);
480            mActiveVirtualSensors.removeItem(handle);
481            delete rec;
482            size--;
483        } else {
484            i++;
485        }
486    }
487    mActiveConnections.remove(connection);
488    BatteryService::cleanup(c->getUid());
489}
490
491status_t SensorService::enable(const sp<SensorEventConnection>& connection,
492        int handle)
493{
494    if (mInitCheck != NO_ERROR)
495        return mInitCheck;
496
497    SensorInterface* sensor = mSensorMap.valueFor(handle);
498    if (sensor == NULL) {
499        return BAD_VALUE;
500    }
501
502    Mutex::Autolock _l(mLock);
503    SensorRecord* rec = mActiveSensors.valueFor(handle);
504    if (rec == 0) {
505        rec = new SensorRecord(connection);
506        mActiveSensors.add(handle, rec);
507        if (sensor->isVirtual()) {
508            mActiveVirtualSensors.add(handle, sensor);
509        }
510    } else {
511        if (rec->addConnection(connection)) {
512            // this sensor is already activated, but we are adding a
513            // connection that uses it. Immediately send down the last
514            // known value of the requested sensor if it's not a
515            // "continuous" sensor.
516            if (sensor->getSensor().getMinDelay() == 0) {
517                sensors_event_t scratch;
518                sensors_event_t& event(mLastEventSeen.editValueFor(handle));
519                if (event.version == sizeof(sensors_event_t)) {
520                    connection->sendEvents(&event, 1);
521                }
522            }
523        }
524    }
525
526    if (connection->addSensor(handle)) {
527        BatteryService::enableSensor(connection->getUid(), handle);
528        // the sensor was added (which means it wasn't already there)
529        // so, see if this connection becomes active
530        if (mActiveConnections.indexOf(connection) < 0) {
531            mActiveConnections.add(connection);
532        }
533    } else {
534        ALOGW("sensor %08x already enabled in connection %p (ignoring)",
535            handle, connection.get());
536    }
537
538    // we are setup, now enable the sensor.
539    status_t err = sensor->activate(connection.get(), true);
540    if (err != NO_ERROR) {
541        // enable has failed, reset our state.
542        cleanupWithoutDisableLocked(connection, handle);
543    }
544    return err;
545}
546
547status_t SensorService::disable(const sp<SensorEventConnection>& connection,
548        int handle)
549{
550    if (mInitCheck != NO_ERROR)
551        return mInitCheck;
552
553    Mutex::Autolock _l(mLock);
554    status_t err = cleanupWithoutDisableLocked(connection, handle);
555    if (err == NO_ERROR) {
556        SensorInterface* sensor = mSensorMap.valueFor(handle);
557        err = sensor ? sensor->activate(connection.get(), false) : status_t(BAD_VALUE);
558    }
559    return err;
560}
561
562status_t SensorService::cleanupWithoutDisable(
563        const sp<SensorEventConnection>& connection, int handle) {
564    Mutex::Autolock _l(mLock);
565    return cleanupWithoutDisableLocked(connection, handle);
566}
567
568status_t SensorService::cleanupWithoutDisableLocked(
569        const sp<SensorEventConnection>& connection, int handle) {
570    SensorRecord* rec = mActiveSensors.valueFor(handle);
571    if (rec) {
572        // see if this connection becomes inactive
573        if (connection->removeSensor(handle)) {
574            BatteryService::disableSensor(connection->getUid(), handle);
575        }
576        if (connection->hasAnySensor() == false) {
577            mActiveConnections.remove(connection);
578        }
579        // see if this sensor becomes inactive
580        if (rec->removeConnection(connection)) {
581            mActiveSensors.removeItem(handle);
582            mActiveVirtualSensors.removeItem(handle);
583            delete rec;
584        }
585        return NO_ERROR;
586    }
587    return BAD_VALUE;
588}
589
590status_t SensorService::setEventRate(const sp<SensorEventConnection>& connection,
591        int handle, nsecs_t ns)
592{
593    if (mInitCheck != NO_ERROR)
594        return mInitCheck;
595
596    SensorInterface* sensor = mSensorMap.valueFor(handle);
597    if (!sensor)
598        return BAD_VALUE;
599
600    if (ns < 0)
601        return BAD_VALUE;
602
603    nsecs_t minDelayNs = sensor->getSensor().getMinDelayNs();
604    if (ns < minDelayNs) {
605        ns = minDelayNs;
606    }
607
608    if (ns < MINIMUM_EVENTS_PERIOD)
609        ns = MINIMUM_EVENTS_PERIOD;
610
611    return sensor->setDelay(connection.get(), handle, ns);
612}
613
614// ---------------------------------------------------------------------------
615
616SensorService::SensorRecord::SensorRecord(
617        const sp<SensorEventConnection>& connection)
618{
619    mConnections.add(connection);
620}
621
622bool SensorService::SensorRecord::addConnection(
623        const sp<SensorEventConnection>& connection)
624{
625    if (mConnections.indexOf(connection) < 0) {
626        mConnections.add(connection);
627        return true;
628    }
629    return false;
630}
631
632bool SensorService::SensorRecord::removeConnection(
633        const wp<SensorEventConnection>& connection)
634{
635    ssize_t index = mConnections.indexOf(connection);
636    if (index >= 0) {
637        mConnections.removeItemsAt(index, 1);
638    }
639    return mConnections.size() ? false : true;
640}
641
642// ---------------------------------------------------------------------------
643
644SensorService::SensorEventConnection::SensorEventConnection(
645        const sp<SensorService>& service, uid_t uid)
646    : mService(service), mChannel(new BitTube()), mUid(uid)
647{
648}
649
650SensorService::SensorEventConnection::~SensorEventConnection()
651{
652    ALOGD_IF(DEBUG_CONNECTIONS, "~SensorEventConnection(%p)", this);
653    mService->cleanupConnection(this);
654}
655
656void SensorService::SensorEventConnection::onFirstRef()
657{
658}
659
660bool SensorService::SensorEventConnection::addSensor(int32_t handle) {
661    Mutex::Autolock _l(mConnectionLock);
662    if (mSensorInfo.indexOf(handle) < 0) {
663        mSensorInfo.add(handle);
664        return true;
665    }
666    return false;
667}
668
669bool SensorService::SensorEventConnection::removeSensor(int32_t handle) {
670    Mutex::Autolock _l(mConnectionLock);
671    if (mSensorInfo.remove(handle) >= 0) {
672        return true;
673    }
674    return false;
675}
676
677bool SensorService::SensorEventConnection::hasSensor(int32_t handle) const {
678    Mutex::Autolock _l(mConnectionLock);
679    return mSensorInfo.indexOf(handle) >= 0;
680}
681
682bool SensorService::SensorEventConnection::hasAnySensor() const {
683    Mutex::Autolock _l(mConnectionLock);
684    return mSensorInfo.size() ? true : false;
685}
686
687status_t SensorService::SensorEventConnection::sendEvents(
688        sensors_event_t const* buffer, size_t numEvents,
689        sensors_event_t* scratch)
690{
691    // filter out events not for this connection
692    size_t count = 0;
693    if (scratch) {
694        Mutex::Autolock _l(mConnectionLock);
695        size_t i=0;
696        while (i<numEvents) {
697            const int32_t curr = buffer[i].sensor;
698            if (mSensorInfo.indexOf(curr) >= 0) {
699                do {
700                    scratch[count++] = buffer[i++];
701                } while ((i<numEvents) && (buffer[i].sensor == curr));
702            } else {
703                i++;
704            }
705        }
706    } else {
707        scratch = const_cast<sensors_event_t *>(buffer);
708        count = numEvents;
709    }
710
711    // NOTE: ASensorEvent and sensors_event_t are the same type
712    ssize_t size = SensorEventQueue::write(mChannel,
713            reinterpret_cast<ASensorEvent const*>(scratch), count);
714    if (size == -EAGAIN) {
715        // the destination doesn't accept events anymore, it's probably
716        // full. For now, we just drop the events on the floor.
717        //ALOGW("dropping %d events on the floor", count);
718        return size;
719    }
720
721    return size < 0 ? status_t(size) : status_t(NO_ERROR);
722}
723
724sp<BitTube> SensorService::SensorEventConnection::getSensorChannel() const
725{
726    return mChannel;
727}
728
729status_t SensorService::SensorEventConnection::enableDisable(
730        int handle, bool enabled)
731{
732    status_t err;
733    if (enabled) {
734        err = mService->enable(this, handle);
735    } else {
736        err = mService->disable(this, handle);
737    }
738    return err;
739}
740
741status_t SensorService::SensorEventConnection::setEventRate(
742        int handle, nsecs_t ns)
743{
744    return mService->setEventRate(this, handle, ns);
745}
746
747// ---------------------------------------------------------------------------
748}; // namespace android
749
750