SensorEventQueue.cpp revision 2ffb24799e579c47a73c992ab567f05c4bf0c962 
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#define LOG_TAG "Sensors"
18
19#include <stdint.h>
20#include <sys/types.h>
21
22#include <utils/Errors.h>
23#include <utils/RefBase.h>
24#include <utils/Looper.h>
25
26#include <gui/Sensor.h>
27#include <gui/SensorChannel.h>
28#include <gui/SensorEventQueue.h>
29#include <gui/ISensorEventConnection.h>
30
31#include <android/sensor.h>
32
33// ----------------------------------------------------------------------------
34namespace android {
35// ----------------------------------------------------------------------------
36
37SensorEventQueue::SensorEventQueue(const sp<ISensorEventConnection>& connection)
38    : mSensorEventConnection(connection)
39{
40}
41
42SensorEventQueue::~SensorEventQueue()
43{
44}
45
46void SensorEventQueue::onFirstRef()
47{
48    mSensorChannel = mSensorEventConnection->getSensorChannel();
49}
50
51int SensorEventQueue::getFd() const
52{
53    return mSensorChannel->getFd();
54}
55
56ssize_t SensorEventQueue::write(ASensorEvent const* events, size_t numEvents)
57{
58    ssize_t size = mSensorChannel->write(events, numEvents * sizeof(events[0]));
59    if (size >= 0) {
60        if (size % sizeof(events[0])) {
61            // partial write!!! should never happen.
62            return -EINVAL;
63        }
64        // returns number of events written
65        size /= sizeof(events[0]);
66    }
67    return size;
68}
69
70ssize_t SensorEventQueue::read(ASensorEvent* events, size_t numEvents)
71{
72    ssize_t size = mSensorChannel->read(events, numEvents*sizeof(events[0]));
73    LOGE_IF(size<0 && size!=-EAGAIN,
74            "SensorChannel::read error (%s)", strerror(-size));
75    if (size >= 0) {
76        if (size % sizeof(events[0])) {
77            // partial read!!! should never happen.
78            LOGE("SensorEventQueue partial read (event-size=%u, read=%d)",
79                    sizeof(events[0]), int(size));
80            return -EINVAL;
81        }
82        // returns number of events read
83        size /= sizeof(events[0]);
84    }
85    return size;
86}
87
88sp<Looper> SensorEventQueue::getLooper() const
89{
90    Mutex::Autolock _l(mLock);
91    if (mLooper == 0) {
92        mLooper = new Looper(true);
93        mLooper->addFd(getFd(), getFd(), ALOOPER_EVENT_INPUT, NULL, NULL);
94    }
95    return mLooper;
96}
97
98status_t SensorEventQueue::waitForEvent() const
99{
100    const int fd = getFd();
101    sp<Looper> looper(getLooper());
102
103    int32_t result;
104    do {
105        result = looper->pollOnce(-1);
106        if (result == ALOOPER_EVENT_ERROR) {
107            LOGE("SensorChannel::waitForEvent error (errno=%d)", errno);
108            result = -EPIPE; // unknown error, so we make up one
109            break;
110        }
111    } while (result != fd);
112
113    return  (result == fd) ? status_t(NO_ERROR) : result;
114}
115
116status_t SensorEventQueue::wake() const
117{
118    sp<Looper> looper(getLooper());
119    looper->wake();
120    return NO_ERROR;
121}
122
123status_t SensorEventQueue::enableSensor(Sensor const* sensor) const {
124    return mSensorEventConnection->enableDisable(sensor->getHandle(), true);
125}
126
127status_t SensorEventQueue::disableSensor(Sensor const* sensor) const {
128    return mSensorEventConnection->enableDisable(sensor->getHandle(), false);
129}
130
131status_t SensorEventQueue::enableSensor(int32_t handle, int32_t us) const {
132    status_t err = mSensorEventConnection->enableDisable(handle, true);
133    if (err == NO_ERROR) {
134        mSensorEventConnection->setEventRate(handle, us2ns(us));
135    }
136    return err;
137}
138
139status_t SensorEventQueue::disableSensor(int32_t handle) const {
140    return mSensorEventConnection->enableDisable(handle, false);
141}
142
143status_t SensorEventQueue::setEventRate(Sensor const* sensor, nsecs_t ns) const {
144    return mSensorEventConnection->setEventRate(sensor->getHandle(), ns);
145}
146
147// ----------------------------------------------------------------------------
148}; // namespace android
149
150