components/permissions/prediction_service/prediction_model_executor.cc

// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/permissions/prediction_service/prediction_model_executor.h"

#include "base/notreached.h"
#include "components/permissions/prediction_service/prediction_common.h"
#include "components/permissions/prediction_service/prediction_request_features.h"
#include "third_party/tflite_support/src/tensorflow_lite_support/cc/task/core/task_utils.h"

namespace permissions {

PredictionModelExecutorInput::PredictionModelExecutorInput() = default;
PredictionModelExecutorInput::~PredictionModelExecutorInput() = default;
PredictionModelExecutorInput::PredictionModelExecutorInput(
    const PredictionModelExecutorInput&) = default;

PredictionModelExecutor::PredictionModelExecutor() = default;
PredictionModelExecutor::~PredictionModelExecutor() = default;

bool PredictionModelExecutor::Preprocess(
    const std::vector<TfLiteTensor*>& input_tensors,
    const PredictionModelExecutorInput& input) {
  model_metadata_ = input.metadata;
  switch (input.request.permission_features()[0].permission_type_case()) {
    case PermissionFeatures::kNotificationPermission:
      request_type_ = RequestType::kNotifications;
      break;
    case PermissionFeatures::kGeolocationPermission:
      request_type_ = RequestType::kGeolocation;
      break;
    default:
      NOTREACHED();
  }

  if (!tflite::task::core::PopulateTensor<float>(
           input.request.client_features().client_stats().avg_deny_rate(),
           input_tensors[0])
           .ok()) {
    return false;
  }

  if (!tflite::task::core::PopulateTensor<float>(
           input.request.client_features().client_stats().avg_dismiss_rate(),
           input_tensors[1])
           .ok()) {
    return false;
  }

  if (!tflite::task::core::PopulateTensor<float>(
           input.request.client_features().client_stats().avg_grant_rate(),
           input_tensors[2])
           .ok()) {
    return false;
  }

  if (!tflite::task::core::PopulateTensor<float>(
           input.request.client_features().client_stats().avg_ignore_rate(),
           input_tensors[3])
           .ok()) {
    return false;
  }

  if (!tflite::task::core::PopulateTensor<float>(
           input.request.permission_features()[0]
               .permission_stats()
               .avg_deny_rate(),
           input_tensors[4])
           .ok()) {
    return false;
  }

  if (!tflite::task::core::PopulateTensor<float>(
           input.request.permission_features()[0]
               .permission_stats()
               .avg_dismiss_rate(),
           input_tensors[5])
           .ok()) {
    return false;
  }

  if (!tflite::task::core::PopulateTensor<float>(
           input.request.permission_features()[0]
               .permission_stats()
               .avg_grant_rate(),
           input_tensors[6])
           .ok()) {
    return false;
  }

  if (!tflite::task::core::PopulateTensor<float>(
           input.request.permission_features()[0]
               .permission_stats()
               .avg_ignore_rate(),
           input_tensors[7])
           .ok()) {
    return false;
  }

  if (!tflite::task::core::PopulateTensor<int64_t>(
           static_cast<int64_t>(input.request.permission_features()[0]
                                    .permission_stats()
                                    .prompts_count()),
           input_tensors[8])
           .ok()) {
    return false;
  }

  if (!tflite::task::core::PopulateTensor<int64_t>(
           static_cast<int64_t>(
               input.request.client_features().client_stats().prompts_count()),
           input_tensors[9])
           .ok()) {
    return false;
  }

  if (!tflite::task::core::PopulateTensor<int64_t>(
           static_cast<int64_t>(input.request.client_features().gesture_enum()),
           input_tensors[10])
           .ok()) {
    return false;
  }

  if (!tflite::task::core::PopulateTensor<int64_t>(
           static_cast<int64_t>(
               input.request.client_features().platform_enum()),
           input_tensors[11])
           .ok()) {
    return false;
  }

  return true;
}

std::optional<GeneratePredictionsResponse> PredictionModelExecutor::Postprocess(
    const std::vector<const TfLiteTensor*>& output_tensors) {
  DCHECK(request_type_ == RequestType::kNotifications ||
         request_type_ == RequestType::kGeolocation);

  if (!model_metadata_ || !model_metadata_->has_not_grant_thresholds()) {
    LOG(WARNING)
        << "[CPSS] Failed to read model thresholds from metadata";
    return std::nullopt;
  }

  std::vector<float> data;
  if (!tflite::task::core::PopulateVector<float>(output_tensors[0], &data)
           .ok()) {
    return std::nullopt;
  }

  // max_likely represents very likely to not grant
  float threshold = model_metadata_->not_grant_thresholds().max_likely();

  GeneratePredictionsResponse response;
  response.mutable_prediction()
      ->Add()
      ->mutable_grant_likelihood()
      ->set_discretized_likelihood(
          data[1] > threshold
              ? PermissionPrediction_Likelihood_DiscretizedLikelihood_VERY_UNLIKELY
              : PermissionPrediction_Likelihood_DiscretizedLikelihood_DISCRETIZED_LIKELIHOOD_UNSPECIFIED);

  return response;
}

}  // namespace permissions