1// Copyright (c) 2010 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_HISTORY_VISIT_TRACKER_H__
6#define CHROME_BROWSER_HISTORY_VISIT_TRACKER_H__
7
8#include <map>
9#include <vector>
10
11#include "base/basictypes.h"
12#include "components/history/core/browser/history_types.h"
13
14namespace history {
15
16// Tracks history transitions between pages. The history backend uses this to
17// link up page transitions to form a chain of page visits, and to set the
18// transition type properly.
19//
20// This class is not thread safe.
21class VisitTracker {
22 public:
23  VisitTracker();
24  ~VisitTracker();
25
26  // Notifications -------------------------------------------------------------
27
28  void AddVisit(ContextID context_id,
29                int32 page_id,
30                const GURL& url,
31                VisitID visit_id);
32
33  // When a RenderProcessHost is destroyed, we want to clear out our saved
34  // transitions/visit IDs for it.
35  void ClearCachedDataForContextID(ContextID context_id);
36
37  // Querying ------------------------------------------------------------------
38
39  // Returns the visit ID for the transition given information about the visit
40  // supplied by the renderer. We will return 0 if there is no appropriate
41  // referring visit.
42  VisitID GetLastVisit(ContextID context_id, int32 page_id, const GURL& url);
43
44 private:
45  struct Transition {
46    GURL url;          // URL that the event happened to.
47    int32 page_id;     // ID generated by the render process host.
48    VisitID visit_id;  // Visit ID generated by history.
49  };
50  typedef std::vector<Transition> TransitionList;
51  typedef std::map<ContextID, TransitionList*> ContextList;
52
53  // Expires oldish items in the given transition list. This keeps the list
54  // size small by removing items that are unlikely to be needed, which is
55  // important for GetReferrer which does brute-force searches of this list.
56  void CleanupTransitionList(TransitionList* transitions);
57
58  // Maps render view hosts to lists of recent transitions.
59  ContextList contexts_;
60
61  DISALLOW_COPY_AND_ASSIGN(VisitTracker);
62};
63
64}  // namespace history
65
66#endif  // CHROME_BROWSER_HISTORY_VISIT_TRACKER_H__
67