Reporting: Cap number of clients in cache.

net/reporting/reporting_cache.h

 // Copyright 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 NET_REPORTING_REPORTING_CACHE_H_
 #define NET_REPORTING_REPORTING_CACHE_H_
 
 #include <map>
 #include <memory>
 #include <set>
 #include <string>
 #include <unordered_map>
 #include <unordered_set>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/stl_util.h"
 #include "base/time/time.h"
 #include "base/values.h"
 #include "net/base/net_export.h"
 #include "net/reporting/reporting_client.h"
 #include "url/gurl.h"
 #include "url/origin.h"
 
+namespace base {
+class TickClock;
+}  // namespace base
+
 namespace net {
 
 class ReportingContext;
 struct ReportingReport;
 
 // The cache holds undelivered reports and clients (per-origin endpoint
 // configurations) in memory. (It is not responsible for persisting them.)
 //
 // This corresponds roughly to the "Reporting cache" in the spec, except that
 // endpoints and clients are stored in a more structurally-convenient way, and
@@ skipping 56 matching lines @@
   // All parameters correspond to the desired values for the fields in
   // |Client|.
   //
   // |endpoint| must use a cryptographic scheme.
   void SetClient(const url::Origin& origin,
                  const GURL& endpoint,
                  ReportingClient::Subdomains subdomains,
                  const std::string& group,
                  base::TimeTicks expires);
 
+  void MarkClientUsed(const url::Origin& origin, const GURL& endpoint);
+
   // Gets all of the clients in the cache, regardless of origin or group.
   //
   // (Clears any existing data in |*clients_out|.)
   void GetClients(std::vector<const ReportingClient*>* clients_out) const;
 
   // Gets all of the clients configured for a particular origin in a particular
   // group. The returned pointers are only guaranteed to be valid if no calls
   // have been made to |SetClient| or |RemoveEndpoint| in between.
   //
   // If no origin match is found, the cache will return clients from the most
@@ skipping 43 matching lines @@
     return base::ContainsKey(pending_reports_, report);
   }
 
   bool IsReportDoomedForTesting(const ReportingReport* report) const {
     return base::ContainsKey(doomed_reports_, report);
   }
 
  private:
   const ReportingReport* FindReportToEvict() const;
 
-  void MaybeAddWildcardClient(const ReportingClient* client);
+  void AddClient(std::unique_ptr<ReportingClient> client,
+                 base::TimeTicks last_used);
 
-  void MaybeRemoveWildcardClient(const ReportingClient* client);
+  void RemoveClient(const ReportingClient* client);
+
+  const ReportingClient* GetClientByOriginAndEndpoint(
+      const url::Origin& origin,
+      const GURL& endpoint) const;
 
   void GetWildcardClientsForDomainAndGroup(
       const std::string& domain,
       const std::string& group,
       std::vector<const ReportingClient*>* clients_out) const;
 
+  const ReportingClient* FindClientToEvict(base::TimeTicks now) const;
+
+  base::TickClock* tick_clock();
+
   ReportingContext* context_;
 
-  // Owns all clients, keyed by origin, then endpoint URL.
-  // (These would be unordered_map, but neither url::Origin nor GURL has a hash
-  // function implemented.)
-  std::map<url::Origin, std::map<GURL, std::unique_ptr<ReportingClient>>>
-      clients_;
-
-  // References but does not own all clients with includeSubdomains set, keyed
-  // by domain name.
-  std::unordered_map<std::string, std::unordered_set<const ReportingClient*>>
-      wildcard_clients_;
-
   // Owns all reports, keyed by const raw pointer for easier lookup.
   std::unordered_map<const ReportingReport*, std::unique_ptr<ReportingReport>>
       reports_;
 
   // Reports that have been marked pending (in use elsewhere and should not be
   // deleted until no longer pending).
   std::unordered_set<const ReportingReport*> pending_reports_;
 
   // Reports that have been marked doomed (would have been deleted, but were
   // pending when the deletion was requested).
   std::unordered_set<const ReportingReport*> doomed_reports_;
 
+  // Owns all clients, keyed by origin, then endpoint URL.
+  // (These would be unordered_map, but neither url::Origin nor GURL has a hash
+  // function implemented.)
+  std::map<url::Origin, std::map<GURL, std::unique_ptr<ReportingClient>>>
+      clients_;
+
+  // References but does not own all clients with includeSubdomains set, keyed
+  // by domain name.
+  std::unordered_map<std::string, std::unordered_set<const ReportingClient*>>
+      wildcard_clients_;
+
+  // The time that each client has last been used.
+  std::unordered_map<const ReportingClient*, base::TimeTicks> client_last_used_;
+
   DISALLOW_COPY_AND_ASSIGN(ReportingCache);
 };
 
 }  // namespace net
 
 #endif  // NET_REPORTING_REPORTING_CACHE_H_