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      1 /*
      2  * Copyright (C) 2016 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 #ifndef CHRE_CORE_SENSOR_REQUEST_H_
     18 #define CHRE_CORE_SENSOR_REQUEST_H_
     19 
     20 #include <cstdint>
     21 
     22 #include "chre_api/chre/sensor.h"
     23 #include "chre/core/nanoapp.h"
     24 #include "chre/util/time.h"
     25 
     26 namespace chre {
     27 
     28 // TODO: Move SensorType and related functions to a new file called
     29 // sensor_type.h and include it here. This will allow using this logic in util
     30 // code withput pulling in the entire SensorRequest class which is only intended
     31 // to be used by the CHRE implementation.
     32 
     33 //! The union of possible CHRE sensor data event type with one sample.
     34 union ChreSensorData {
     35   struct chreSensorThreeAxisData threeAxisData;
     36   struct chreSensorOccurrenceData occurrenceData;
     37   struct chreSensorFloatData floatData;
     38   struct chreSensorByteData byteData;
     39 };
     40 
     41 /**
     42  * This SensorType is designed to wrap constants provided by the CHRE API
     43  * to improve type-safety. In addition, an unknown sensor type is provided
     44  * for dealing with sensors that are not defined as per the CHRE API
     45  * specification. The details of these sensors are left to the CHRE API
     46  * sensor definitions.
     47  */
     48 enum class SensorType {
     49   Unknown,
     50   Accelerometer,
     51   InstantMotion,
     52   StationaryDetect,
     53   Gyroscope,
     54   GeomagneticField,
     55   Pressure,
     56   Light,
     57   Proximity,
     58   AccelerometerTemperature,
     59   GyroscopeTemperature,
     60   UncalibratedAccelerometer,
     61   UncalibratedGyroscope,
     62   UncalibratedGeomagneticField,
     63 
     64   // Note to future developers: don't forget to update the implementation of
     65   // 1) getSensorTypeName,
     66   // 2) getSensorTypeFromUnsignedInt,
     67   // 3) getUnsignedIntFromSensorType,
     68   // 4) getSensorSampleTypeFromSensorType
     69   // 5) sensorTypeIsOneShot
     70   // 6) sensorTypeIsOnChange
     71   // when adding or removing a new entry here :)
     72   // Have a nice day.
     73 
     74   //! The number of sensor types including unknown. This entry must be last.
     75   SENSOR_TYPE_COUNT,
     76 };
     77 
     78 /**
     79  * This SensorSampleType is designed to help classify SensorType's data type in
     80  * event handling.
     81  */
     82 enum class SensorSampleType {
     83   Byte,
     84   Float,
     85   Occurrence,
     86   ThreeAxis,
     87   Unknown,
     88 };
     89 
     90 /**
     91  * Returns a string representation of the given sensor type.
     92  *
     93  * @param sensorType The sensor type to obtain a string for.
     94  * @return A string representation of the sensor type.
     95  */
     96 const char *getSensorTypeName(SensorType sensorType);
     97 
     98 /**
     99  * Returns a sensor sample event type for a given sensor type. The sensor type
    100  * must not be SensorType::Unknown. This is a fatal error.
    101  *
    102  * @param sensorType The type of the sensor.
    103  * @return The event type for a sensor sample of the given sensor type.
    104  */
    105 uint16_t getSampleEventTypeForSensorType(SensorType sensorType);
    106 
    107 /**
    108  * Returns a sensor type for a given sensor sample event type.
    109  *
    110  * @param eventType The event type for a sensor sample.
    111  * @return The type of the sensor.
    112  */
    113 SensorType getSensorTypeForSampleEventType(uint16_t eventType);
    114 
    115 /**
    116  * @return An index into an array for a given sensor type. This is useful to map
    117  * sensor type to array index quickly. The range returned corresponds to any
    118  * SensorType except for Unknown starting from zero to the maximum value sensor
    119  * with no gaps.
    120  */
    121 constexpr size_t getSensorTypeArrayIndex(SensorType sensorType);
    122 
    123 /**
    124  * @return The number of valid sensor types in the SensorType enum.
    125  */
    126 constexpr size_t getSensorTypeCount();
    127 
    128 /**
    129  * Translates an unsigned integer as provided by a CHRE-compliant nanoapp to a
    130  * SensorType. If the integer sensor type does not match one of the internal
    131  * sensor types, SensorType::Unknown is returned.
    132  *
    133  * @param sensorType The integer sensor type.
    134  * @return The strongly-typed sensor if a match is found or SensorType::Unknown.
    135  */
    136 SensorType getSensorTypeFromUnsignedInt(uint8_t sensorType);
    137 
    138 /**
    139  * Translates a SensorType to an unsigned integer as provided by CHRE API. If
    140  * the sensor type is SensorType::Unknown, 0 is returned.
    141  *
    142  * @param sensorType The strongly-typed sensor.
    143  * @return The integer sensor type if sensorType is not SensorType::Unknown.
    144  */
    145 uint8_t getUnsignedIntFromSensorType(SensorType sensorType);
    146 
    147 /**
    148  * Provides a stable handle for a CHRE sensor type. This handle is exposed to
    149  * CHRE nanoapps as a way to refer to sensors that they are subscribing to. This
    150  * API is not expected to be called with SensorType::Unknown as nanoapps are not
    151  * able to subscribe to the Unknown sensor type.
    152  *
    153  * @param sensorType The type of the sensor to obtain a handle for.
    154  * @return The handle for a given sensor.
    155  */
    156 constexpr uint32_t getSensorHandleFromSensorType(SensorType sensorType);
    157 
    158 /**
    159  * Maps a sensor handle to a SensorType or returns SensorType::Unknown if the
    160  * provided handle is invalid.
    161  *
    162  * @param handle The sensor handle for a sensor.
    163  * @return The sensor type for a given handle.
    164  */
    165 constexpr SensorType getSensorTypeFromSensorHandle(uint32_t handle);
    166 
    167 /**
    168  * Maps a sensorType to its SensorSampleType.
    169  *
    170  * @param sensorType The type of the sensor to obtain its SensorSampleType for.
    171  * @return The SensorSampleType of the sensorType.
    172  */
    173 SensorSampleType getSensorSampleTypeFromSensorType(SensorType sensorType);
    174 
    175 /**
    176  * This SensorMode is designed to wrap constants provided by the CHRE API to
    177  * imrpove type-safety. The details of these modes are left to the CHRE API mode
    178  * definitions contained in the chreSensorConfigureMode enum.
    179  */
    180 enum class SensorMode {
    181   Off,
    182   ActiveContinuous,
    183   ActiveOneShot,
    184   PassiveContinuous,
    185   PassiveOneShot,
    186 };
    187 
    188 /**
    189  * @return true if the sensor mode is considered to be active and would cause a
    190  * sensor to be powered on in order to get sensor data.
    191  */
    192 constexpr bool sensorModeIsActive(SensorMode sensorMode);
    193 
    194 /**
    195  * @return true if the sensor mode is considered to be contunuous.
    196  */
    197 constexpr bool sensorModeIsContinuous(SensorMode sensorMode);
    198 
    199 /**
    200  * @return true if the sensor mode is considered to be one-shot.
    201  */
    202 constexpr bool sensorModeIsOneShot(SensorMode sensorMode);
    203 
    204 /**
    205  * Translates a CHRE API enum sensor mode to a SensorMode. This function also
    206  * performs input validation and will default to SensorMode::Off if the provided
    207  * value is not a valid enum value.
    208  *
    209  * @param enumSensorMode A potentially unsafe CHRE API enum sensor mode.
    210  * @return Returns a SensorMode given a CHRE API enum sensor mode.
    211  */
    212 SensorMode getSensorModeFromEnum(enum chreSensorConfigureMode enumSensorMode);
    213 
    214 /**
    215  * Indicates whether the sensor type is a one-shot sensor.
    216  *
    217  * @param sensorType The sensor type of the sensor.
    218  * @return true if the sensor is a one-shot sensor.
    219  */
    220 bool sensorTypeIsOneShot(SensorType sensorType);
    221 
    222 /**
    223  * Indicates whether the sensor type is an on-change sensor.
    224  *
    225  * @param sensorType The sensor type of the sensor.
    226  * @return true if the sensor is an on-change sensor.
    227  */
    228 bool sensorTypeIsOnChange(SensorType sensorType);
    229 
    230 /**
    231  * Models a request for sensor data. This class implements the API set forth by
    232  * the RequestMultiplexer container.
    233  */
    234 class SensorRequest {
    235  public:
    236   /**
    237    * Default constructs a sensor request to the minimal possible configuration.
    238    * The sensor is disabled and the interval and latency are both set to zero.
    239    */
    240   SensorRequest();
    241 
    242   /**
    243    * Constructs a sensor request given a mode, interval and latency.
    244    *
    245    * @param mode The mode of the sensor request.
    246    * @param interval The interval between samples.
    247    * @param latency The maximum amount of time to batch samples before
    248    *        delivering to a client.
    249    */
    250   SensorRequest(SensorMode mode, Nanoseconds interval, Nanoseconds latency);
    251 
    252   /**
    253    * Constructs a sensor request given an owning nanoapp, mode, interval and
    254    * latency.
    255    *
    256    * @param nanoapp The nanoapp that made this request.
    257    * @param mode The mode of the sensor request.
    258    * @param interval The interval between samples.
    259    * @param latency The maximum amount of time to batch samples before
    260    *        delivering to a client.
    261    */
    262   SensorRequest(Nanoapp *nanoapp, SensorMode mode, Nanoseconds interval,
    263                 Nanoseconds latency);
    264 
    265   /**
    266    * Performs an equivalency comparison of two sensor requests. This determines
    267    * if the effective request for sensor data is the same as another.
    268    *
    269    * @param request The request to compare against.
    270    * @return Returns true if this request is equivalent to another.
    271    */
    272   bool isEquivalentTo(const SensorRequest& request) const;
    273 
    274   /**
    275    * Assigns the current request to the maximal superset of the mode, rate
    276    * and latency of the other request.
    277    *
    278    * @param request The other request to compare the attributes of.
    279    * @return true if any of the attributes of this request changed.
    280    */
    281   bool mergeWith(const SensorRequest& request);
    282 
    283   /**
    284    * @return Returns the interval of samples for this request.
    285    */
    286   Nanoseconds getInterval() const;
    287 
    288   /**
    289    * @return Returns the maximum amount of time samples can be batched prior to
    290    * dispatching to the client.
    291    */
    292   Nanoseconds getLatency() const;
    293 
    294   /**
    295    * @return The mode of this request.
    296    */
    297   SensorMode getMode() const;
    298 
    299   /**
    300    * @return The nanoapp that owns this sensor request.
    301    */
    302   Nanoapp *getNanoapp() const;
    303 
    304  private:
    305   //! The nanoapp that made this request. This will be nullptr when returned by
    306   //! the generateIntersectionOf method.
    307   Nanoapp *mNanoapp = nullptr;
    308 
    309   //! The interval between samples for this request.
    310   Nanoseconds mInterval;
    311 
    312   //! The maximum amount of time samples can be batched prior to dispatching to
    313   //! the client
    314   Nanoseconds mLatency;
    315 
    316   //! The mode of this request.
    317   SensorMode mMode;
    318 };
    319 
    320 }  // namespace chre
    321 
    322 #include "chre/core/sensor_request_impl.h"
    323 
    324 #endif  // CHRE_CORE_SENSOR_REQUEST_H_
    325