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 "url/gurl.h"
  16
  17 namespace dom_distiller {
  18
  19 struct DistilledPageInfo {
  20   std::string title;
  21   std::string html;
  22   std::string next_page_url;
  23   std::string prev_page_url;
  24   std::vector<std::string> image_urls;
  25   DistilledPageInfo();
  26   ~DistilledPageInfo();
  27
  28  private:
  29   DISALLOW_COPY_AND_ASSIGN(DistilledPageInfo);
  30 };
  31
  32 class SourcePageHandle {
  33  public:
  34   virtual ~SourcePageHandle() {}
  35 };
  36
  37 // Injects JavaScript into a page, and uses it to extract and return long-form
  38 // content. The class can be reused to load and distill multiple pages,
  39 // following the state transitions described along with the class's states.
  40 // Constructing a DistillerPage should be cheap, as some of the instances can be
  41 // thrown away without ever being used.
  42 class DistillerPage {
  43  public:
  44   typedef base::Callback<void(scoped_ptr<DistilledPageInfo> distilled_page,
  45                               bool distillation_successful)>
  46       DistillerPageCallback;
  47
  48   DistillerPage();
  49   virtual ~DistillerPage();
  50
  51   // Loads a URL. |OnDistillationDone| is called when the load completes or
  52   // fails. May be called when the distiller is idle. Callers can assume that,
  53   // for a given |url| and |options|, any DistillerPage implementation will
  54   // extract the same content.
  55   void DistillPage(const GURL& url,
  56                    const dom_distiller::proto::DomDistillerOptions options,
  57                    const DistillerPageCallback& callback);
  58
  59   // Called when the JavaScript execution completes. |page_url| is the url of
  60   // the distilled page. |value| contains data returned by the script.
  61   virtual void OnDistillationDone(const GURL& page_url,
  62                                   const base::Value* value);
  63
  64  protected:
  65   // Called by |DistillPage| to carry out platform-specific instructions to load
  66   // and distill the |url| using the provided |script|. The extracted content
  67   // should be the same regardless of the DistillerPage implementation.
  68   virtual void DistillPageImpl(const GURL& url, const std::string& script) = 0;
  69
  70  private:
  71   bool ready_;
  72   DistillerPageCallback distiller_page_callback_;
  73   DISALLOW_COPY_AND_ASSIGN(DistillerPage);
  74 };
  75
  76 // Factory for generating a |DistillerPage|.
  77 class DistillerPageFactory {
  78  public:
  79   virtual ~DistillerPageFactory();
  80
  81   // Constructs and returns a new DistillerPage. The implementation of this
  82   // should be very cheap, since the pages can be thrown away without being
  83   // used.
  84   virtual scoped_ptr<DistillerPage> CreateDistillerPage() const = 0;
  85   virtual scoped_ptr<DistillerPage> CreateDistillerPageWithHandle(
  86       scoped_ptr<SourcePageHandle> handle) const = 0;
  87 };
  88
  89 }  // namespace dom_distiller
  90
  91 #endif  // COMPONENTS_DOM_DISTILLER_CORE_DISTILLER_PAGE_H_