components/dom_distiller/core/distiller_page.h

   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/geometry/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   // The value returned between the JavaScript and the DistillerPage can be
  59   // either a dictionary with all the content, or a stringified version.
  60   virtual bool StringifyOutput() = 0;
  61
  62   // If true, forces the creation of a new window context to evaluate the
  63   // JavaScript.
  64   virtual bool CreateNewContext() = 0;
  65
  66  private:
  67   bool ready_;
  68   DistillerPageCallback distiller_page_callback_;
  69   DISALLOW_COPY_AND_ASSIGN(DistillerPage);
  70 };
  71
  72 // Factory for generating a |DistillerPage|.
  73 class DistillerPageFactory {
  74  public:
  75   virtual ~DistillerPageFactory();
  76
  77   // Constructs and returns a new DistillerPage. The implementation of this
  78   // should be very cheap, since the pages can be thrown away without being
  79   // used.
  80   virtual scoped_ptr<DistillerPage> CreateDistillerPage(
  81       const gfx::Size& render_view_size) const = 0;
  82   virtual scoped_ptr<DistillerPage> CreateDistillerPageWithHandle(
  83       scoped_ptr<SourcePageHandle> handle) const = 0;
  84 };
  85
  86 }  // namespace dom_distiller
  87
  88 #endif  // COMPONENTS_DOM_DISTILLER_CORE_DISTILLER_PAGE_H_