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      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    protected:
     45     Observer();
     46     virtual ~Observer();
     47   };
     48 
     49   // Before calling the destructor, the caller must invalidate the handle by
     50   // calling either OnNavigateAway or OnCancel.
     51   virtual ~PrerenderHandle();
     52 
     53   void SetObserver(Observer* observer);
     54 
     55   // The launcher is navigating away from the context that launched this
     56   // prerender. The prerender will likely stay alive briefly though, in case we
     57   // are going through a redirect chain that will target it.
     58   void OnNavigateAway();
     59 
     60   // The launcher has taken explicit action to remove this prerender (for
     61   // instance, removing a link element from a document). This call invalidates
     62   // the handle. If the prerender handle is already invalid, this call does
     63   // nothing.
     64   void OnCancel();
     65 
     66   // True if this prerender is currently active.
     67   bool IsPrerendering() const;
     68 
     69   // True if we started a prerender, and it has finished loading.
     70   bool IsFinishedLoading() const;
     71 
     72   // Returns whether the prerender matches the URL provided.
     73   bool Matches(
     74       const GURL& url,
     75       const content::SessionStorageNamespace* session_storage_namespace) const;
     76 
     77   // Returns whether this PrerenderHandle represents the same prerender as
     78   // the other PrerenderHandle object specified.
     79   bool RepresentingSamePrerenderAs(PrerenderHandle* other) const;
     80 
     81  private:
     82   friend class PrerenderManager;
     83 
     84   explicit PrerenderHandle(PrerenderManager::PrerenderData* prerender_data);
     85 
     86   void AdoptPrerenderDataFrom(PrerenderHandle* other_handle);
     87 
     88   // From PrerenderContents::Observer:
     89   virtual void OnPrerenderStart(PrerenderContents* prerender_contents) OVERRIDE;
     90   virtual void OnPrerenderStopLoading(PrerenderContents* prerender_contents)
     91       OVERRIDE;
     92   virtual void OnPrerenderStop(PrerenderContents* prerender_contents) OVERRIDE;
     93   virtual void OnPrerenderCreatedMatchCompleteReplacement(
     94       PrerenderContents* contents, PrerenderContents* replacement) OVERRIDE;
     95 
     96   Observer* observer_;
     97 
     98   base::WeakPtr<PrerenderManager::PrerenderData> prerender_data_;
     99   base::WeakPtrFactory<PrerenderHandle> weak_ptr_factory_;
    100 
    101   DISALLOW_COPY_AND_ASSIGN(PrerenderHandle);
    102 };
    103 
    104 }  // namespace prerender
    105 
    106 #endif  // CHROME_BROWSER_PRERENDER_PRERENDER_HANDLE_H_
    107