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 "chrome/browser/history/history_types.h" 13 14 namespace 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. 21 class VisitTracker { 22 public: 23 VisitTracker(); 24 ~VisitTracker(); 25 26 // Notifications ------------------------------------------------------------- 27 28 void AddVisit(const void* host, 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 NotifyRenderProcessHostDestruction(const void* host); 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(const void* host, 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<const void*, TransitionList*> HostList; 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 HostList hosts_; 60 61 DISALLOW_COPY_AND_ASSIGN(VisitTracker); 62 }; 63 64 } // namespace history 65 66 #endif // CHROME_BROWSER_HISTORY_VISIT_TRACKER_H__ 67