src/general_test/basic_audio_test.cc

/*
 * 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.
 */
#include <cinttypes>

#include "audio_validation.h"
#include "chre/util/macros.h"
#include "chre/util/nanoapp/log.h"

#include <general_test/basic_audio_test.h>

#include <shared/send_message.h>
#include <shared/time_util.h>

#define LOG_TAG "[ChreBasicAudioTest]"

using chre::test_shared::checkAudioSamplesAllSame;
using chre::test_shared::checkAudioSamplesAllZeros;

using nanoapp_testing::kOneSecondInNanoseconds;
using nanoapp_testing::sendFatalFailureToHost;
using nanoapp_testing::sendSuccessToHost;

namespace general_test {
namespace {

//! This is a reasonably high limit on the number of audio sources that a system
//! would expose. Use this to verify that there are no gaps in the source
//! handles.
constexpr uint32_t kMaxAudioSources = 128;

//! This is a reasonably high limit on the sample rate for a source that the
//! system would expose. Sampling rates above 96kHz are likely to be too high
//! for always-on low-power use-cases. Yes, this omits 192kHz, but that is
//! generally reserved for professional audio/recording and mixing applications.
//! Even 96kHz is a stretch, but capping it here allows room to grow. Expected
//! values are more like 16kHz.
constexpr uint32_t kMaxAudioSampleRate = 96000;

//! Provide a floor for the sampling rate of an audio source that the system
//! would expose. Nyquist theorem dictates that the maximum frequency that can
//! be reproduced from given sequence of samples is equal to half that of the
//! sampling rate. This sets a lower bound to try to detect bugs or glitches.
constexpr uint32_t kMinAudioSampleRate = 4000;

//! Provide a floor for buffer duration. This ensures that at the maximum
//! sample rate possible, a minimum number of samples will be delivered in
//! a batch.
constexpr uint64_t kMinBufferDuration =
    (kOneSecondInNanoseconds / kMaxAudioSampleRate) * 10;

//! Provide a ceiling for the maximum buffer duration. This is to catch buggy
//! descriptors of audio sources who expose very long buffers of data which are
//! not practical for always-on, low-power use-cases.
constexpr uint64_t kMaxBufferDuration = kOneSecondInNanoseconds * 120;

//! While a variety of sample rates are supported, for the purposes of basic
//! audio data validation, we buffer about 4 seconds worth of PCM audio data
//! sampled at 16KHz.
constexpr uint32_t kRequiredSampleRate = 16000;

/**
 * @return true if the character is ASCII printable.
 */
bool isAsciiPrintable(char c) {
  // A simple enough test to verify that a character is printable. These
  // constants can be verified by reviewing an ASCII chart. All printable
  // characters that we care about for CHRE lie between these two bounds and are
  // contiguous.
  return (c >= ' ' && c <= '~');
}

/**
 * @return true if the supplied string is printable, null-terminated and not
 * longer than the supplied length (including null-terminator).
 */
bool verifyStringWithLength(const char *str, size_t length) {
  bool nullTerminatorFound = false;
  bool isPrintable = true;
  for (size_t i = 0; i < length; i++) {
    if (str[i] == '\0') {
      nullTerminatorFound = true;
      break;
    } else if (!isAsciiPrintable(str[i])) {
      isPrintable = false;
      break;
    }
  }

  return (isPrintable && nullTerminatorFound);
}

/**
 * Validates the fields of a chreAudioSource provided by the framework and posts
 * a failure if the source descriptor is malformed.
 *
 * @return true if the source was valid.
 */
bool validateAudioSource(uint32_t handle,
                         const struct chreAudioSource &source) {
  bool valid = false;
  if (!verifyStringWithLength(source.name, CHRE_AUDIO_SOURCE_NAME_MAX_SIZE)) {
    sendFatalFailureToHost("Invalid audio source name for handle ", &handle);
  } else if (source.sampleRate > kMaxAudioSampleRate ||
             source.sampleRate < kMinAudioSampleRate) {
    sendFatalFailureToHost("Invalid audio sample rate for handle ", &handle);
  } else if (source.minBufferDuration < kMinBufferDuration ||
             source.minBufferDuration > kMaxBufferDuration) {
    sendFatalFailureToHost("Invalid min buffer duration for handle ", &handle);
  } else if (source.maxBufferDuration < kMinBufferDuration ||
             source.maxBufferDuration > kMaxBufferDuration) {
    sendFatalFailureToHost("Invalid max buffer duration for handle ", &handle);
  } else if (source.format != CHRE_AUDIO_DATA_FORMAT_8_BIT_U_LAW &&
             source.format != CHRE_AUDIO_DATA_FORMAT_16_BIT_SIGNED_PCM) {
    sendFatalFailureToHost("Invalid audio format for handle ", &handle);
  } else {
    valid = true;
  }

  return valid;
}

bool validateMinimumAudioSource(const struct chreAudioSource &source) {
  // CHQTS requires a 16kHz, PCM-format, 2 second buffer.
  constexpr uint64_t kRequiredBufferDuration = 2 * kOneSecondInNanoseconds;

  // Ensure that the minimum buffer size is less than or equal to the required
  // size.
  return (source.sampleRate == kRequiredSampleRate &&
          source.minBufferDuration <= kRequiredBufferDuration &&
          source.maxBufferDuration >= kRequiredBufferDuration &&
          source.format == CHRE_AUDIO_DATA_FORMAT_16_BIT_SIGNED_PCM);
}

/**
 * Attempts to query for all audio sources up to kMaxAudioSources and posts a
 * failure if a gap is found in the handles or the provided descriptor is
 * invalid.
 */
void validateAudioSources() {
  uint32_t validHandleCount = 0;
  bool previousSourceFound = true;
  bool minimumRequirementMet = false;
  for (uint32_t handle = 0; handle < kMaxAudioSources; handle++) {
    struct chreAudioSource audioSource;
    bool sourceFound = chreAudioGetSource(handle, &audioSource);
    if (sourceFound) {
      validHandleCount++;
      if (!previousSourceFound) {
        sendFatalFailureToHost("Gap detected in audio handles at ", &handle);
      } else {
        bool valid = validateAudioSource(handle, audioSource);
        if (valid && !minimumRequirementMet) {
          minimumRequirementMet = validateMinimumAudioSource(audioSource);
        }
      }
    }

    previousSourceFound = sourceFound;
  }

  if (validHandleCount > 0) {
    if (!minimumRequirementMet) {
      sendFatalFailureToHost(
          "Failed to meet minimum audio source requirements");
    }

    if (validHandleCount == kMaxAudioSources) {
      sendFatalFailureToHost("System is reporting too many audio sources");
    }
  }
}

/**
 * Attempts to request audio data from the default microphone handle (0),
 * posts a failure if the data request failed
 */
void requestAudioData() {
  constexpr uint32_t kAudioHandle = 0;
  struct chreAudioSource audioSource;

  if (!chreAudioGetSource(kAudioHandle, &audioSource)) {
    sendFatalFailureToHost("Failed to query source for handle 0");
  } else if (!chreAudioConfigureSource(kAudioHandle, true /* enable */,
                                       audioSource.minBufferDuration,
                                       audioSource.minBufferDuration)) {
    sendFatalFailureToHost("Failed to request audio data for handle 0");
  }
}

void handleAudioDataEvent(const chreAudioDataEvent *dataEvent) {
  constexpr uint32_t kAudioHandle = 0;

  // A count of the number of data events we've received - we stop
  // the test after receiving 2 data events.
  static uint8_t numDataEventsSoFar = 1;

  if (dataEvent == nullptr) {
    sendFatalFailureToHost("Null event data");
  } else if (dataEvent->samplesS16 == nullptr) {
    sendFatalFailureToHost("Null audio data frame");
  } else if (dataEvent->sampleCount == 0) {
    sendFatalFailureToHost("0 samples in audio data frame");
  } else {
    struct chreAudioSource audioSource;
    if (!chreAudioGetSource(kAudioHandle, &audioSource)) {
      sendFatalFailureToHost("Failed to get audio source for handle 0");
    } else {
      // Per the CHRE Audio API requirements, it is expected that we exactly
      // the number of samples that we ask for - we verify that here.
      const auto kNumSamplesExpected =
          static_cast<uint32_t>(audioSource.minBufferDuration *
                                kRequiredSampleRate / kOneSecondInNanoseconds);
      if (dataEvent->sampleCount != kNumSamplesExpected) {
        LOGE("Unexpected num samples - Expected: %" PRIu32 ", Actual: %" PRIu32,
             kNumSamplesExpected, dataEvent->sampleCount);
        uint32_t sampleCountDifference =
            (kNumSamplesExpected > dataEvent->sampleCount)
                ? (kNumSamplesExpected - dataEvent->sampleCount)
                : (dataEvent->sampleCount - kNumSamplesExpected);
        sendFatalFailureToHost("Unexpected number of samples received",
                               &sampleCountDifference);
      }
    }
  }

  if (!checkAudioSamplesAllZeros(dataEvent->samplesS16,
                                 dataEvent->sampleCount)) {
    sendFatalFailureToHost("All audio samples were zeros");
  } else if (!checkAudioSamplesAllSame(dataEvent->samplesS16,
                                       dataEvent->sampleCount)) {
    sendFatalFailureToHost("All audio samples were identical");
  }

  if (numDataEventsSoFar == 2) {
    if (!chreAudioConfigureSource(kAudioHandle, false /* enable */,
                                  0 /* bufferDuration */,
                                  0 /* deliveryInterval */)) {
      sendFatalFailureToHost("Failed to disable audio source for handle 0");
    } else {
      sendSuccessToHost();
    }
  } else {
    ++numDataEventsSoFar;
  }
}

bool isAudioSupported() {
  struct chreAudioSource source;
  constexpr uint32_t kRequiredAudioHandle = 0;
  // If the DUT supports CHRE audio, then audio handle 0 is required to be
  // valid. There is the risk that the chreAudioGetSource function might
  // legitimately fail however - we should replace this function when CHRE
  // audio capabilities in b/185155280 are implemented.
  // TODO (b/185155280): fix this query
  return chreAudioGetSource(kRequiredAudioHandle, &source);
}
}  // anonymous namespace

BasicAudioTest::BasicAudioTest()
    : Test(CHRE_API_VERSION_1_2), mInMethod(false), mState(State::kPreStart) {}

void BasicAudioTest::setUp(uint32_t messageSize, const void * /* message */) {
  if (messageSize != 0) {
    sendFatalFailureToHost("Beginning message expects 0 additional bytes, got ",
                           &messageSize);
  }

  if (!isAudioSupported()) {
    sendSuccessToHost();

  } else {
    validateAudioSources();

    mState = State::kExpectingAudioData;

    requestAudioData();
  }
}

void BasicAudioTest::handleEvent(uint32_t senderInstanceId, uint16_t eventType,
                                 const void *eventData) {
  UNUSED_VAR(senderInstanceId);

  if (mInMethod) {
    sendFatalFailureToHost("handleEvent() invoked while already in method.");
  }

  mInMethod = true;

  if (mState == State::kPreStart) {
    unexpectedEvent(eventType);
  } else {
    switch (eventType) {
      case CHRE_EVENT_AUDIO_SAMPLING_CHANGE:
        /* This event is received, but not relevant to this test since we're
         * mostly interested in the audio data, so we ignore it. */
        break;

      case CHRE_EVENT_AUDIO_DATA:
        handleAudioDataEvent(
            static_cast<const chreAudioDataEvent *>(eventData));
        break;

      default:
        unexpectedEvent(eventType);
        break;
    }
  }

  mInMethod = false;
}

}  // namespace general_test