[subresource_filter] SB throttle can send multiple speculative requests.

components/subresource_filter/content/browser/subresource_filter_safe_browsing_client.h

+// Copyright (c) 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_SUBRESOURCE_FILTER_CONTENT_BROWSER_SUBRESOURCE_FILTER_SAFE_BROWSING_CLIENT_H_
+#define COMPONENTS_SUBRESOURCE_FILTER_CONTENT_BROWSER_SUBRESOURCE_FILTER_SAFE_BROWSING_CLIENT_H_
+
+#include <memory>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "components/safe_browsing_db/v4_local_database_manager.h"
+#include "url/gurl.h"
+
+namespace base {
+class SingleThreadTaskRunner;
+class Timer;
+}  // namespace base
+
+namespace subresource_filter {
+
+class SubresourceFilterSafeBrowsingActivationThrottle;
+class SubresourceFilterSafeBrowsingClientRequest;
+
+// Created on the UI thread but used on the IO thread to communicate with the
+// safe browsing service.
+//
+// The class is expected to accompany a single navigation. If a check request
+// comes in for URL B while URL A is in flight, we cancel the check to URL A.
+//
+// Consumers of the class need some way of determining the order of requests, so
+// they send in request_ids which are paired with each check.
+class SubresourceFilterSafeBrowsingClient {
+ public:
+  SubresourceFilterSafeBrowsingClient(
+      std::unique_ptr<base::Timer> timer,
+      scoped_refptr<safe_browsing::SafeBrowsingDatabaseManager>
+          database_manager,
+      const base::WeakPtr<SubresourceFilterSafeBrowsingActivationThrottle>&
+          throttle,
+      scoped_refptr<base::SingleThreadTaskRunner> io_task_runner);
+
+  ~SubresourceFilterSafeBrowsingClient();
+
+  void CheckUrlOnIO(const GURL& url, int request_id);
+
+  void OnCheckBrowseUrlResult(
+      SubresourceFilterSafeBrowsingClientRequest* request,
+      safe_browsing::SBThreatType threat_type,
+      const safe_browsing::ThreatMetadata& metadata);
+
+ private:
+  // Only set from the default for testing.
+  std::unique_ptr<base::Timer> timer_;
+  std::unique_ptr<SubresourceFilterSafeBrowsingClientRequest> current_request_;
+
+  scoped_refptr<safe_browsing::SafeBrowsingDatabaseManager> database_manager_;
+
+  base::WeakPtr<SubresourceFilterSafeBrowsingActivationThrottle> throttle_;
+  scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
+
+  DISALLOW_COPY_AND_ASSIGN(SubresourceFilterSafeBrowsingClient);
+};
+
+// This class is scoped to a single database check, and it lives on the IO
+// thread exclusively.
+class SubresourceFilterSafeBrowsingClientRequest
+    : public safe_browsing::SafeBrowsingDatabaseManager::Client {
+ public:
+  SubresourceFilterSafeBrowsingClientRequest(
+      base::Timer* timer,
+      const GURL& url,
+      int request_id,
+      scoped_refptr<safe_browsing::SafeBrowsingDatabaseManager>
+          database_manager,
+      SubresourceFilterSafeBrowsingClient* client);
+  ~SubresourceFilterSafeBrowsingClientRequest() override;
+
+  void Start();
+
+  void OnCheckBrowseUrlResult(
+      const GURL& url,
+      safe_browsing::SBThreatType threat_type,
+      const safe_browsing::ThreatMetadata& metadata) override;
+
+  const GURL& url() const { return url_; }
+
+  int request_id() const { return request_id_; }
+
+  static const base::TimeDelta kCheckURLTimeout;
+
+ private:
+  // Callback for when the safe browsing check has taken longer than
+  // kCheckURLTimeout.
+  void OnCheckUrlTimeout();
+
+  const GURL url_;
+  const int request_id_;
+
+  scoped_refptr<safe_browsing::SafeBrowsingDatabaseManager> database_manager_;
+  SubresourceFilterSafeBrowsingClient* client_ = nullptr;
+
+  // Timer to abort the safe browsing check if it takes too long. Must outlive
+  // this class.
+  base::Timer* timer_;
+
+  // Only used for DCHECKing.
+  bool is_cancelled_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(SubresourceFilterSafeBrowsingClientRequest);
+};
+
+}  // namespace subresource_filter
+
+#endif  // COMPONENTS_SUBRESOURCE_FILTER_CONTENT_BROWSER_SUBRESOURCE_FILTER_SAFE_BROWSING_CLIENT_H_