components/sync_driver/revisit/sessions_page_revisit_observer.h

   1 // Copyright 2015 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 COMPONENTS_SYNC_DRIVER_REVISIT_SESSIONS_PAGE_REVISIT_OBSERVER_H_
   6 #define COMPONENTS_SYNC_DRIVER_REVISIT_SESSIONS_PAGE_REVISIT_OBSERVER_H_
   7
   8 #include <vector>
   9
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "components/sync_driver/revisit/page_visit_observer.h"
  13 #include "url/gurl.h"
  14
  15 namespace sessions {
  16 struct SessionTab;
  17 }  // namespace sessions
  18
  19 namespace sync_driver {
  20
  21 struct SyncedSession;
  22
  23 class CurrentTabMatcher;
  24 class OffsetTabMatcher;
  25
  26 // A simple interface to abstract away who is providing sessions.
  27 class ForeignSessionsProvider {
  28  public:
  29   // Fills the already instantiated passed vector with all foreign sessions.
  30   // Returned boolean representes if there were foreign sessions and the vector
  31   // should be examimed.
  32   virtual bool GetAllForeignSessions(
  33       std::vector<const sync_driver::SyncedSession*>* sessions) = 0;
  34   virtual ~ForeignSessionsProvider() {}
  35 };
  36
  37 // An implementation of PageVisitObserver that checks the given page's url
  38 // against in memory session information to detect if we've seen this page
  39 // before, constituting a revisit. Then histogram information is emitted about
  40 // this page navigation.
  41 class SessionsPageRevisitObserver
  42     : public PageVisitObserver,
  43       public base::SupportsWeakPtr<SessionsPageRevisitObserver> {
  44  public:
  45   explicit SessionsPageRevisitObserver(
  46       scoped_ptr<ForeignSessionsProvider> provider);
  47   ~SessionsPageRevisitObserver() override;
  48   void OnPageVisit(const GURL& url, const TransitionType transition) override;
  49
  50  private:
  51   friend class SessionsPageRevisitObserverTest;
  52
  53   // Although the signature is identical to OnPageVisit(...), this method
  54   // actually does all of the work. The assumption is that this method is the
  55   // target of a PostTask call coming from OnPageVisit(...).
  56   void CheckForRevisit(const GURL& url, const TransitionType transition);
  57
  58   scoped_ptr<ForeignSessionsProvider> provider_;
  59
  60   DISALLOW_COPY_AND_ASSIGN(SessionsPageRevisitObserver);
  61 };
  62
  63 }  // namespace sync_driver
  64
  65 #endif  // COMPONENTS_SYNC_DRIVER_REVISIT_SESSIONS_PAGE_REVISIT_OBSERVER_H_