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// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chromeos/components/quick_answers/utils/language_detector.h"
#include "base/functional/callback.h"
#include "base/metrics/field_trial_params.h"
#include "ui/base/l10n/l10n_util.h"
namespace quick_answers {
namespace {
constexpr double kSelectedTextConfidenceThreshold = 0.9;
constexpr double kSurroundingTextConfidenceThreshold = 0.9;
std::optional<std::string> GetLanguageWithConfidence(
const std::vector<chromeos::machine_learning::mojom::TextLanguagePtr>&
languages,
double confidence_threshold) {
// The languages are sorted according to the confidence score, from the
// highest to the lowest (according to the mojom method documentation).
if (!languages.empty() &&
languages.front()->confidence > confidence_threshold) {
return std::string(l10n_util::GetLanguage(languages.front()->locale));
}
return std::nullopt;
}
} // namespace
LanguageDetector::LanguageDetector(
chromeos::machine_learning::mojom::TextClassifier* text_classifier)
: text_classifier_(text_classifier) {}
LanguageDetector::~LanguageDetector() = default;
void LanguageDetector::DetectLanguage(const std::string& surrounding_text,
const std::string& selected_text,
DetectLanguageCallback callback) {
text_classifier_->FindLanguages(
selected_text,
base::BindOnce(&LanguageDetector::FindLanguagesForSelectedTextCallback,
weak_factory_.GetWeakPtr(), surrounding_text,
std::move(callback)));
}
void LanguageDetector::FindLanguagesForSelectedTextCallback(
const std::string& surrounding_text,
DetectLanguageCallback callback,
std::vector<chromeos::machine_learning::mojom::TextLanguagePtr> languages) {
auto locale = GetLanguageWithConfidence(std::move(languages),
kSelectedTextConfidenceThreshold);
if (locale.has_value()) {
std::move(callback).Run(std::move(locale));
return;
}
// If find language failed or the confidence level is too low, fall back to
// find language for the surrounding text.
text_classifier_->FindLanguages(
surrounding_text,
base::BindOnce(&LanguageDetector::FindLanguagesForSurroundingTextCallback,
weak_factory_.GetWeakPtr(), std::move(callback)));
}
void LanguageDetector::FindLanguagesForSurroundingTextCallback(
DetectLanguageCallback callback,
std::vector<chromeos::machine_learning::mojom::TextLanguagePtr> languages) {
auto locale =
GetLanguageWithConfidence(languages, kSurroundingTextConfidenceThreshold);
std::move(callback).Run(std::move(locale));
}
} // namespace quick_answers
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