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// Copyright 2014 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/safe_search_api/url_checker.h"
#include <string>
#include <string_view>
#include <utility>
#include <vector>
#include "base/functional/bind.h"
#include "base/functional/callback.h"
#include "base/logging.h"
#include "base/metrics/histogram_functions.h"
#include "base/metrics/histogram_macros.h"
#include "base/time/time.h"
#include "base/values.h"
namespace safe_search_api {
namespace {
const size_t kDefaultCacheSize = 1000;
const size_t kDefaultCacheTimeoutSeconds = 3600;
constexpr std::string_view kCacheHitMetricKey{"Net.SafeSearch.CacheHit"};
} // namespace
struct URLChecker::Check {
Check(const GURL& url, CheckCallback callback);
~Check();
GURL url;
std::vector<CheckCallback> callbacks;
};
URLChecker::Check::Check(const GURL& url, CheckCallback callback) : url(url) {
callbacks.push_back(std::move(callback));
}
URLChecker::Check::~Check() = default;
URLChecker::CheckResult::CheckResult(Classification classification)
: classification(classification), timestamp(base::TimeTicks::Now()) {}
URLChecker::URLChecker(std::unique_ptr<URLCheckerClient> async_checker)
: URLChecker(std::move(async_checker), kDefaultCacheSize) {}
URLChecker::URLChecker(std::unique_ptr<URLCheckerClient> async_checker,
size_t cache_size)
: async_checker_(std::move(async_checker)),
cache_(cache_size),
cache_timeout_(base::Seconds(kDefaultCacheTimeoutSeconds)) {}
URLChecker::~URLChecker() = default;
void URLChecker::MaybeScheduleAsyncCheck(const GURL& url,
CheckCallback callback) {
// See if we already have a check in progress for this URL.
for (const auto& check : checks_in_progress_) {
if (check->url == url) {
DVLOG(1) << "Adding to pending check for " << url.spec();
check->callbacks.push_back(std::move(callback));
return;
}
}
auto it = checks_in_progress_.insert(
checks_in_progress_.begin(),
std::make_unique<Check>(url, std::move(callback)));
async_checker_->CheckURL(url,
base::BindOnce(&URLChecker::OnAsyncCheckComplete,
weak_factory_.GetWeakPtr(), it));
}
bool URLChecker::CheckURL(const GURL& url, CheckCallback callback) {
auto cache_it = cache_.Get(url);
if (cache_it != cache_.end()) {
const CheckResult& result = cache_it->second;
base::TimeDelta age = base::TimeTicks::Now() - result.timestamp;
if (age < cache_timeout_) {
DVLOG(1) << "Cache hit! " << url.spec() << " is "
<< (result.classification == Classification::UNSAFE ? "NOT" : "")
<< " safe";
std::move(callback).Run(
url, result.classification,
ClassificationDetails{
.reason = ClassificationDetails::Reason::kCachedResponse});
base::UmaHistogramEnumeration(kCacheHitMetricKey,
CacheAccessStatus::kHit);
return true;
}
DVLOG(1) << "Outdated cache entry for " << url.spec() << ", purging";
cache_.Erase(cache_it);
base::UmaHistogramEnumeration(kCacheHitMetricKey,
CacheAccessStatus::kOutdated);
MaybeScheduleAsyncCheck(url, std::move(callback));
return false;
}
base::UmaHistogramEnumeration(kCacheHitMetricKey,
CacheAccessStatus::kNotFound);
MaybeScheduleAsyncCheck(url, std::move(callback));
return false;
}
void URLChecker::OnAsyncCheckComplete(CheckList::iterator it,
const GURL& url,
ClientClassification api_classification) {
bool uncertain = api_classification == ClientClassification::kUnknown;
// Fallback to a |SAFE| classification when the result is not explicitly
// marked as restricted.
Classification classification = Classification::SAFE;
if (api_classification == ClientClassification::kRestricted) {
classification = Classification::UNSAFE;
}
std::vector<CheckCallback> callbacks = std::move(it->get()->callbacks);
checks_in_progress_.erase(it);
if (!uncertain) {
cache_.Put(url, CheckResult(classification));
}
for (CheckCallback& callback : callbacks) {
std::move(callback).Run(
url, classification,
ClassificationDetails{
.reason =
uncertain
? ClassificationDetails::Reason::kFailedUseDefault
: ClassificationDetails::Reason::kFreshServerResponse});
}
}
} // namespace safe_search_api
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