chrome/browser/prerender/prerender_handle.h

   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
  13 class GURL;
  14
  15 namespace content {
  16 class SessionStorageNamespace;
  17 }
  18
  19 namespace prerender {
  20
  21 class 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.
  30 class 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   PrerenderContents* contents() const;
  77
  78   // Returns whether the prerender matches the URL provided.
  79   bool Matches(
  80       const GURL& url,
  81       const content::SessionStorageNamespace* session_storage_namespace) const;
  82
  83   // Returns whether this PrerenderHandle represents the same prerender as
  84   // the other PrerenderHandle object specified.
  85   bool RepresentingSamePrerenderAs(PrerenderHandle* other) const;
  86
  87   // Retrieves the SessionStorageNamespace of the underlying prerender, if
  88   // available.
  89   content::SessionStorageNamespace* GetSessionStorageNamespace() const;
  90
  91   // Returns the child id of the prerender.
  92   int GetChildId() const;
  93
  94  private:
  95   friend class PrerenderManager;
  96
  97   explicit PrerenderHandle(PrerenderManager::PrerenderData* prerender_data);
  98
  99   void AdoptPrerenderDataFrom(PrerenderHandle* other_handle);
 100
 101   // From PrerenderContents::Observer:
 102   virtual void OnPrerenderStart(PrerenderContents* prerender_contents) OVERRIDE;
 103   virtual void OnPrerenderStopLoading(PrerenderContents* prerender_contents)
 104       OVERRIDE;
 105   virtual void OnPrerenderStop(PrerenderContents* prerender_contents) OVERRIDE;
 106   virtual void OnPrerenderCreatedMatchCompleteReplacement(
 107       PrerenderContents* contents, PrerenderContents* replacement) OVERRIDE;
 108
 109   Observer* observer_;
 110
 111   base::WeakPtr<PrerenderManager::PrerenderData> prerender_data_;
 112   base::WeakPtrFactory<PrerenderHandle> weak_ptr_factory_;
 113
 114   DISALLOW_COPY_AND_ASSIGN(PrerenderHandle);
 115 };
 116
 117 }  // namespace prerender
 118
 119 #endif  // CHROME_BROWSER_PRERENDER_PRERENDER_HANDLE_H_