Provide monitoring of usage for a storage type and origin

webkit/browser/quota/storage_monitor.h

+// Copyright 2014 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 WEBKIT_BROWSER_QUOTA_STORAGE_MONITOR_H_
+#define WEBKIT_BROWSER_QUOTA_STORAGE_MONITOR_H_
+
+#include <map>
+
+#include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
+#include "base/timer/timer.h"
+#include "webkit/browser/quota/storage_observer.h"
+
+namespace quota {
+
+class QuotaManager;
+
+// This class dispatches storage events to observers of a common
+// StorageObserver::Filter.
+class WEBKIT_STORAGE_BROWSER_EXPORT_PRIVATE StorageObserverList {
+ public:
+  StorageObserverList();
+  virtual ~StorageObserverList();
+
+  // Adds/removes an observer.
+  void AddObserver(StorageObserver* observer,
+                   const StorageObserver::MonitorParams& params);
+  void RemoveObserver(StorageObserver* observer);
+
+  // Returns the number of observers.
+  int ObserverCount() const;
+
+  // Forwards a storage change to observers. The event may be dispatched
+  // immediately to an observer or after a delay, depending on the desired event
+  // rate of the observer.
+  void OnStorageChange(const StorageObserver::Event& event);
+
+  // Dispatch an event to observers that require it.
+  void MaybeDispatchEvent(const StorageObserver::Event& event);
+
+  // Ensure the specified observer receives the next dispatched event.
+  void ScheduleUpdateForObserver(StorageObserver* observer);
+
+ private:
+  struct WEBKIT_STORAGE_BROWSER_EXPORT_PRIVATE ObserverState {
+    GURL origin;
+    base::TimeTicks last_notification_time;
+    base::TimeDelta rate;
+    bool requires_update;
+
+    ObserverState();
+  };
+  typedef std::map<StorageObserver*, ObserverState> StorageObserverStateMap;
+
+  void DispatchPendingEvent();
+
+  StorageObserverStateMap observers_;
+  base::OneShotTimer<StorageObserverList> notification_timer_;
+  StorageObserver::Event pending_event_;
+
+  friend class StorageMonitorTestBase;
+
+  DISALLOW_COPY_AND_ASSIGN(StorageObserverList);
+};
+
+
+// Manages the storage observers of a common host. Caches the usage and quota of
+// the host to avoid accumulating for every change.
+class WEBKIT_STORAGE_BROWSER_EXPORT_PRIVATE HostStorageObservers {
+ public:
+  explicit HostStorageObservers(QuotaManager* quota_manager);
+  virtual ~HostStorageObservers();
+
+  bool is_initialized() const { return initialized_; }
+
+  // Adds/removes an observer.
+  void AddObserver(
+      StorageObserver* observer,
+      const StorageObserver::MonitorParams& params);
+  void RemoveObserver(StorageObserver* observer);
+  bool ContainsObservers() const;
+
+  // Handles a usage change.
+  void NotifyUsageChange(const StorageObserver::Filter& filter, int64 delta);
+
+ private:
+  void StartInitialization(const StorageObserver::Filter& filter);
+  void GotHostUsageAndQuota(const StorageObserver::Filter& filter,
+                            QuotaStatusCode status,
+                            int64 usage,
+                            int64 quota);
+  void DispatchEvent(const StorageObserver::Filter& filter, bool is_update);
+
+  QuotaManager* quota_manager_;
+  StorageObserverList observers_;
+
+  // Flags used during initialization of the cached properties.
+  bool initialized_;
+  bool initializing_;
+  bool event_occurred_before_init_;
+
+  // Cached accumulated usage and quota for the host.
+  int64 cached_usage_;
+  int64 cached_quota_;
+
+  base::WeakPtrFactory<HostStorageObservers> weak_factory_;
+
+  friend class StorageMonitorTestBase;
+
+  DISALLOW_COPY_AND_ASSIGN(HostStorageObservers);
+};
+
+
+// Manages the observers of a common storage type.
+class WEBKIT_STORAGE_BROWSER_EXPORT_PRIVATE StorageTypeObservers {
+ public:
+  explicit StorageTypeObservers(QuotaManager* quota_manager);
+  virtual ~StorageTypeObservers();
+
+  // Adds and removes an observer.
+  void AddObserver(StorageObserver* observer,
+                   const StorageObserver::MonitorParams& params);
+  void RemoveObserver(StorageObserver* observer);
+  void RemoveObserverForFilter(StorageObserver* observer,
+                               const StorageObserver::Filter& filter);
+
+  // Returns the observers of a specific host.
+  const HostStorageObservers* GetHostObservers(const std::string& host) const;
+
+  // Handles a usage change.
+  void NotifyUsageChange(const StorageObserver::Filter& filter, int64 delta);
+
+ private:
+  typedef std::map<std::string, HostStorageObservers*> HostObserversMap;
+
+  QuotaManager* quota_manager_;
+  HostObserversMap host_observers_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(StorageTypeObservers);
+};
+
+
+// Storage monitor manages observers and dispatches storage events to them.
+class WEBKIT_STORAGE_BROWSER_EXPORT_PRIVATE StorageMonitor {
+ public:
+  explicit StorageMonitor(QuotaManager* quota_manager);
+  virtual ~StorageMonitor();
+
+  // Adds and removes an observer.
+  void AddObserver(StorageObserver* observer,
+                   const StorageObserver::MonitorParams& params);
+  void RemoveObserver(StorageObserver* observer);
+  void RemoveObserverForFilter(StorageObserver* observer,
+                               const StorageObserver::Filter& filter);
+
+  // Returns the observers of a specific storage type.
+  const StorageTypeObservers* GetStorageTypeObservers(
+      StorageType storage_type) const;
+
+  // Handles a usage change.
+  void NotifyUsageChange(const StorageObserver::Filter& filter, int64 delta);
+
+ private:
+  typedef std::map<StorageType, StorageTypeObservers*> StorageTypeObserversMap;
+
+  QuotaManager* quota_manager_;
+  StorageTypeObserversMap storage_type_observers_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(StorageMonitor);
+};
+
+}  // namespace quota
+
+#endif  // WEBKIT_BROWSER_QUOTA_STORAGE_MONITOR_H_