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      1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CHROME_BROWSER_SYNC_UTIL_EXTENSIONS_ACTIVITY_MONITOR_H_
      6 #define CHROME_BROWSER_SYNC_UTIL_EXTENSIONS_ACTIVITY_MONITOR_H_
      7 #pragma once
      8 
      9 #include <map>
     10 
     11 #include "base/message_loop.h"
     12 #include "base/synchronization/lock.h"
     13 #include "content/common/notification_observer.h"
     14 #include "content/common/notification_registrar.h"
     15 
     16 namespace browser_sync {
     17 
     18 // A class to monitor usage of extensions APIs to send to sync servers, with
     19 // the ability to purge data once sync servers have acknowledged it (successful
     20 // commit response).
     21 //
     22 // This can be used from any thread (it is a 'monitor' in the synchronization
     23 // sense as well), HOWEVER
     24 //
     25 // *** IT MUST BE DELETED FROM THE UI LOOP ***
     26 //
     27 // Consider using MessageLoop::DeleteSoon. (Yes, this means if you allocate
     28 // an ExtensionsActivityMonitor on a thread other than UI, you must 'new' it).
     29 class ExtensionsActivityMonitor : public NotificationObserver {
     30  public:
     31   // A data record of activity performed by extension |extension_id|.
     32   struct Record {
     33     Record() : bookmark_write_count(0U) {}
     34 
     35     // The human-readable ID identifying the extension responsible
     36     // for the activity reported in this Record.
     37     std::string extension_id;
     38 
     39     // How many times the extension successfully invoked a write
     40     // operation through the bookmarks API since the last CommitMessage.
     41     uint32 bookmark_write_count;
     42   };
     43 
     44   typedef std::map<std::string, Record> Records;
     45 
     46   // Creates an ExtensionsActivityMonitor to monitor extensions activities on
     47   // BrowserThread::UI.
     48   ExtensionsActivityMonitor();
     49   ~ExtensionsActivityMonitor();
     50 
     51   // Fills |buffer| with snapshot of current records in constant time by
     52   // swapping.  This is done mutually exclusively w.r.t methods of this class.
     53   void GetAndClearRecords(Records* buffer);
     54 
     55   // Add |records| piece-wise (by extension id) to the set of active records.
     56   // This is done mutually exclusively w.r.t the methods of this class.
     57   void PutRecords(const Records& records);
     58 
     59   // NotificationObserver implementation.  Called on |ui_loop_|.
     60   virtual void Observe(NotificationType type,
     61                        const NotificationSource& source,
     62                        const NotificationDetails& details);
     63  private:
     64   Records records_;
     65   mutable base::Lock records_lock_;
     66 
     67   // Used only from UI loop.
     68   NotificationRegistrar registrar_;
     69 };
     70 
     71 }  // namespace browser_sync
     72 
     73 #endif  // CHROME_BROWSER_SYNC_UTIL_EXTENSIONS_ACTIVITY_MONITOR_H_
     74