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// Copyright 2022 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/reduce_accept_language/browser/reduce_accept_language_service.h"
#include <string>
#include "base/json/json_reader.h"
#include "base/metrics/histogram_functions.h"
#include "base/metrics/histogram_macros.h"
#include "base/strings/string_split.h"
#include "base/time/time.h"
#include "components/content_settings/core/browser/content_settings_utils.h"
#include "components/content_settings/core/browser/host_content_settings_map.h"
#include "components/content_settings/core/common/content_settings_constraints.h"
#include "components/content_settings/core/common/content_settings_types.h"
#include "components/content_settings/core/common/content_settings_utils.h"
#include "components/language/core/browser/language_prefs.h"
#include "components/language/core/browser/pref_names.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/render_frame_host.h"
#include "content/public/browser/render_process_host.h"
#include "net/http/http_util.h"
#include "services/network/public/cpp/features.h"
#include "url/gurl.h"
#include "url/origin.h"
namespace reduce_accept_language {
namespace {
const char kReduceAcceptLanguageSettingKey[] = "reduce-accept-language";
} // namespace
ReduceAcceptLanguageService::ReduceAcceptLanguageService(
HostContentSettingsMap* settings_map,
PrefService* pref_service,
bool is_incognito)
: settings_map_(settings_map), is_incognito_(is_incognito) {
DCHECK(settings_map_);
#if BUILDFLAG(IS_CHROMEOS)
const std::string& key = language::prefs::kPreferredLanguages;
#else
const std::string& key = language::prefs::kAcceptLanguages;
#endif
pref_accept_language_.Init(
key, pref_service,
base::BindRepeating(&ReduceAcceptLanguageService::UpdateAcceptLanguage,
base::Unretained(this)));
// StringPrefMember Init doesn't trigger the callback observer, we need to
// explicitly set the accept Language after init.
UpdateAcceptLanguage();
}
ReduceAcceptLanguageService::~ReduceAcceptLanguageService() = default;
void ReduceAcceptLanguageService::Shutdown() {
user_accept_languages_.clear();
pref_accept_language_.Destroy();
}
std::optional<std::string> ReduceAcceptLanguageService::GetReducedLanguage(
const url::Origin& origin) {
const GURL& url = origin.GetURL();
// Only reduce accept-language in http and https scheme.
if (!url.SchemeIsHTTPOrHTTPS())
return std::nullopt;
// Record the time spent getting the reduced accept language to better
// understand whether this prefs read can introduce any large latency.
SCOPED_UMA_HISTOGRAM_TIMER_MICROS("ReduceAcceptLanguage.FetchLatencyUs");
const base::Value& accept_language_rule = settings_map_->GetWebsiteSetting(
url, GURL(), ContentSettingsType::REDUCED_ACCEPT_LANGUAGE, nullptr);
if (accept_language_rule.is_none()) {
return std::nullopt;
}
DCHECK(accept_language_rule.is_dict());
const base::Value* language_value =
accept_language_rule.GetDict().Find(kReduceAcceptLanguageSettingKey);
if (language_value == nullptr) {
return std::nullopt;
}
// We should guarantee reduce accept language always be Type::String since
// we save it as string in the Prefs.
DCHECK(language_value->is_string());
return std::make_optional(language_value->GetString());
}
std::vector<std::string> ReduceAcceptLanguageService::GetUserAcceptLanguages()
const {
return user_accept_languages_;
}
void ReduceAcceptLanguageService::PersistReducedLanguage(
const url::Origin& origin,
const std::string& language) {
DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
const GURL url = origin.GetURL();
if (!url.is_valid() || !url.SchemeIsHTTPOrHTTPS())
return;
const base::TimeTicks start_time = base::TimeTicks::Now();
base::Value::Dict accept_language_dictionary;
base::TimeDelta cache_duration =
network::features::kReduceAcceptLanguageCacheDuration.Get();
accept_language_dictionary.Set(kReduceAcceptLanguageSettingKey, language);
content_settings::ContentSettingConstraints constraints;
constraints.set_lifetime(cache_duration);
constraints.set_session_model(content_settings::mojom::SessionModel::DURABLE);
settings_map_->SetWebsiteSettingDefaultScope(
url, GURL(), ContentSettingsType::REDUCED_ACCEPT_LANGUAGE,
base::Value(std::move(accept_language_dictionary)), constraints);
// Record the time spent getting the reduce accept language.
base::TimeDelta duration = base::TimeTicks::Now() - start_time;
base::UmaHistogramTimes("ReduceAcceptLanguage.StoreLatency", duration);
base::UmaHistogramCounts100("ReduceAcceptLanguage.UpdateSize",
language.size());
}
void ReduceAcceptLanguageService::ClearReducedLanguage(
const url::Origin& origin) {
const GURL& url = origin.GetURL();
// Only reduce accept-language in http and https scheme.
if (!url.SchemeIsHTTPOrHTTPS())
return;
SCOPED_UMA_HISTOGRAM_TIMER("ReduceAcceptLanguage.ClearLatency");
settings_map_->SetWebsiteSettingDefaultScope(
url, GURL(), ContentSettingsType::REDUCED_ACCEPT_LANGUAGE, base::Value());
}
void ReduceAcceptLanguageService::UpdateAcceptLanguage() {
// In incognito mode return only the first language.
std::string accept_languages_str = net::HttpUtil::ExpandLanguageList(
is_incognito_
? language::GetFirstLanguage(pref_accept_language_.GetValue())
: pref_accept_language_.GetValue());
user_accept_languages_ = base::SplitString(
accept_languages_str, ",", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
base::UmaHistogramBoolean(
"ReduceAcceptLanguage.AcceptLanguagePrefValueIsEmpty",
user_accept_languages_.empty());
}
} // namespace reduce_accept_language
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