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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.
#ifndef COMPONENTS_SAFE_SEARCH_API_URL_CHECKER_H_
#define COMPONENTS_SAFE_SEARCH_API_URL_CHECKER_H_
#include <list>
#include <memory>
#include "base/containers/lru_cache.h"
#include "base/functional/callback_forward.h"
#include "base/memory/weak_ptr.h"
#include "base/time/time.h"
#include "components/safe_search_api/url_checker_client.h"
#include "url/gurl.h"
namespace safe_search_api {
// The SafeSearch API classification of a URL.
enum class Classification { SAFE, UNSAFE };
// Additional details regarding how the `Classification` result was determined.
struct ClassificationDetails {
enum class Reason {
// Chrome sent a fresh external request to the server, and received a valid
// response.
kFreshServerResponse,
// Chrome used a cached response, stored from a previous successful request
// to the server.
kCachedResponse,
// Chrome tried but failed to query the server, and defaulted to
// `Classification::SAFE`.
kFailedUseDefault,
};
Reason reason;
};
// These values are sent to Uma to understand Cache utilization. Must not be
// renumbered.
enum class CacheAccessStatus {
// Entry was found.
kHit = 0,
// Entry was not found.
kNotFound = 1,
// Entry was found but was stale.
kOutdated = 2,
kMaxValue = kOutdated,
};
// This class uses one implementation of URLCheckerClient to check the
// classification of the content on a given URL and returns the result
// asynchronously via a callback. It is also responsible for the synchronous
// logic such as caching, the injected URLCheckerClient is who makes the
// async request.
class URLChecker {
public:
// Used to report whether |url| should be blocked. Called from CheckURL.
using CheckCallback = base::OnceCallback<void(const GURL&,
Classification classification,
ClassificationDetails details)>;
explicit URLChecker(std::unique_ptr<URLCheckerClient> async_checker);
URLChecker(std::unique_ptr<URLCheckerClient> async_checker,
size_t cache_size);
URLChecker(const URLChecker&) = delete;
URLChecker& operator=(const URLChecker&) = delete;
~URLChecker();
// Returns whether |callback| was run synchronously.
bool CheckURL(const GURL& url, CheckCallback callback);
void SetCacheTimeoutForTesting(const base::TimeDelta& timeout) {
cache_timeout_ = timeout;
}
private:
struct Check;
struct CheckResult {
CheckResult() = delete;
explicit CheckResult(Classification classification);
Classification classification;
base::TimeTicks timestamp;
};
using CheckList = std::list<std::unique_ptr<Check>>;
void OnAsyncCheckComplete(CheckList::iterator it,
const GURL& url,
ClientClassification classification);
// Either reuses pending check for given url if it already exists (see
// checks_in_progress_), or schedules a new one.
void MaybeScheduleAsyncCheck(const GURL& url, CheckCallback callback);
std::unique_ptr<URLCheckerClient> async_checker_;
CheckList checks_in_progress_;
base::LRUCache<GURL, CheckResult> cache_;
base::TimeDelta cache_timeout_;
base::WeakPtrFactory<URLChecker> weak_factory_{this};
};
} // namespace safe_search_api
#endif // COMPONENTS_SAFE_SEARCH_API_URL_CHECKER_H_
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