prerender_handle.h revision 4e180b6a0b4720a9b8e9e959a882386f690f08ff 
1// Copyright (c) 2012 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_PRERENDER_PRERENDER_HANDLE_H_
6#define CHROME_BROWSER_PRERENDER_PRERENDER_HANDLE_H_
7
8#include "base/basictypes.h"
9#include "base/memory/weak_ptr.h"
10#include "base/threading/non_thread_safe.h"
11#include "chrome/browser/prerender/prerender_manager.h"
12
13class GURL;
14
15namespace content {
16class SessionStorageNamespace;
17}
18
19namespace prerender {
20
21class PrerenderContents;
22
23// A class representing a running prerender to a client of the PrerenderManager.
24// Methods on PrerenderManager which start prerenders return a caller-owned
25// PrerenderHandle* to the client (or NULL if they are unable to start a
26// prerender). Calls on the handle of a prerender that is not running at no-ops.
27// Destroying a handle before a prerender starts will prevent it from ever
28// starting. Destroying a handle while a prerendering is running will stop the
29// prerender, without making any calls to the observer.
30class PrerenderHandle : public base::NonThreadSafe,
31                        public PrerenderContents::Observer {
32 public:
33  class Observer {
34   public:
35    // Signals that the prerender has started running.
36    virtual void OnPrerenderStart(PrerenderHandle* handle) = 0;
37
38    // Signals that the prerender has had its load event.
39    virtual void OnPrerenderStopLoading(PrerenderHandle* handle) = 0;
40
41    // Signals that the prerender has stopped running.
42    virtual void OnPrerenderStop(PrerenderHandle* handle) = 0;
43
44    // Signals that this prerender has just become a MatchComplete replacement.
45    virtual void OnPrerenderCreatedMatchCompleteReplacement(
46        PrerenderHandle* handle) = 0;
47
48   protected:
49    Observer();
50    virtual ~Observer();
51  };
52
53  // Before calling the destructor, the caller must invalidate the handle by
54  // calling either OnNavigateAway or OnCancel.
55  virtual ~PrerenderHandle();
56
57  void SetObserver(Observer* observer);
58
59  // The launcher is navigating away from the context that launched this
60  // prerender. The prerender will likely stay alive briefly though, in case we
61  // are going through a redirect chain that will target it.
62  void OnNavigateAway();
63
64  // The launcher has taken explicit action to remove this prerender (for
65  // instance, removing a link element from a document). This call invalidates
66  // the handle. If the prerender handle is already invalid, this call does
67  // nothing.
68  void OnCancel();
69
70  // True if this prerender is currently active.
71  bool IsPrerendering() const;
72
73  // True if we started a prerender, and it has finished loading.
74  bool IsFinishedLoading() const;
75
76  // Returns whether the prerender matches the URL provided.
77  bool Matches(
78      const GURL& url,
79      const content::SessionStorageNamespace* session_storage_namespace) const;
80
81  // Returns whether this PrerenderHandle represents the same prerender as
82  // the other PrerenderHandle object specified.
83  bool RepresentingSamePrerenderAs(PrerenderHandle* other) const;
84
85  // Retrieves the SessionStorageNamespace of the underlying prerender, if
86  // available.
87  content::SessionStorageNamespace* GetSessionStorageNamespace() const;
88
89  // Returns the child id of the prerender.
90  int GetChildId() const;
91
92 private:
93  friend class PrerenderManager;
94
95  explicit PrerenderHandle(PrerenderManager::PrerenderData* prerender_data);
96
97  void AdoptPrerenderDataFrom(PrerenderHandle* other_handle);
98
99  // From PrerenderContents::Observer:
100  virtual void OnPrerenderStart(PrerenderContents* prerender_contents) OVERRIDE;
101  virtual void OnPrerenderStopLoading(PrerenderContents* prerender_contents)
102      OVERRIDE;
103  virtual void OnPrerenderStop(PrerenderContents* prerender_contents) OVERRIDE;
104  virtual void OnPrerenderCreatedMatchCompleteReplacement(
105      PrerenderContents* contents, PrerenderContents* replacement) OVERRIDE;
106
107  Observer* observer_;
108
109  base::WeakPtr<PrerenderManager::PrerenderData> prerender_data_;
110  base::WeakPtrFactory<PrerenderHandle> weak_ptr_factory_;
111
112  DISALLOW_COPY_AND_ASSIGN(PrerenderHandle);
113};
114
115}  // namespace prerender
116
117#endif  // CHROME_BROWSER_PRERENDER_PRERENDER_HANDLE_H_
118