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      1 // Copyright 2013 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 COMPONENTS_DOM_DISTILLER_CORE_DISTILLER_PAGE_H_
      6 #define COMPONENTS_DOM_DISTILLER_CORE_DISTILLER_PAGE_H_
      7 
      8 #include <string>
      9 
     10 #include "base/callback.h"
     11 #include "base/memory/scoped_ptr.h"
     12 #include "base/memory/weak_ptr.h"
     13 #include "base/values.h"
     14 #include "third_party/dom_distiller_js/dom_distiller.pb.h"
     15 #include "ui/gfx/size.h"
     16 #include "url/gurl.h"
     17 
     18 namespace dom_distiller {
     19 
     20 class SourcePageHandle {
     21  public:
     22   virtual ~SourcePageHandle() {}
     23 };
     24 
     25 // Injects JavaScript into a page, and uses it to extract and return long-form
     26 // content. The class can be reused to load and distill multiple pages,
     27 // following the state transitions described along with the class's states.
     28 // Constructing a DistillerPage should be cheap, as some of the instances can be
     29 // thrown away without ever being used.
     30 class DistillerPage {
     31  public:
     32   typedef base::Callback<
     33       void(scoped_ptr<proto::DomDistillerResult> distilled_page,
     34            bool distillation_successful)> DistillerPageCallback;
     35 
     36   DistillerPage();
     37   virtual ~DistillerPage();
     38 
     39   // Loads a URL. |OnDistillationDone| is called when the load completes or
     40   // fails. May be called when the distiller is idle. Callers can assume that,
     41   // for a given |url| and |options|, any DistillerPage implementation will
     42   // extract the same content.
     43   void DistillPage(const GURL& url,
     44                    const proto::DomDistillerOptions options,
     45                    const DistillerPageCallback& callback);
     46 
     47   // Called when the JavaScript execution completes. |page_url| is the url of
     48   // the distilled page. |value| contains data returned by the script.
     49   virtual void OnDistillationDone(const GURL& page_url,
     50                                   const base::Value* value);
     51 
     52  protected:
     53   // Called by |DistillPage| to carry out platform-specific instructions to load
     54   // and distill the |url| using the provided |script|. The extracted content
     55   // should be the same regardless of the DistillerPage implementation.
     56   virtual void DistillPageImpl(const GURL& url, const std::string& script) = 0;
     57 
     58  private:
     59   bool ready_;
     60   DistillerPageCallback distiller_page_callback_;
     61   DISALLOW_COPY_AND_ASSIGN(DistillerPage);
     62 };
     63 
     64 // Factory for generating a |DistillerPage|.
     65 class DistillerPageFactory {
     66  public:
     67   virtual ~DistillerPageFactory();
     68 
     69   // Constructs and returns a new DistillerPage. The implementation of this
     70   // should be very cheap, since the pages can be thrown away without being
     71   // used.
     72   virtual scoped_ptr<DistillerPage> CreateDistillerPage(
     73       const gfx::Size& render_view_size) const = 0;
     74   virtual scoped_ptr<DistillerPage> CreateDistillerPageWithHandle(
     75       scoped_ptr<SourcePageHandle> handle) const = 0;
     76 };
     77 
     78 }  // namespace dom_distiller
     79 
     80 #endif  // COMPONENTS_DOM_DISTILLER_CORE_DISTILLER_PAGE_H_
     81