ios/chrome/browser/dom_distiller/model/distiller_viewer.h

// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef IOS_CHROME_BROWSER_DOM_DISTILLER_MODEL_DISTILLER_VIEWER_H_
#define IOS_CHROME_BROWSER_DOM_DISTILLER_MODEL_DISTILLER_VIEWER_H_

#include <memory>
#include <string>

#include "components/dom_distiller/core/dom_distiller_request_view_base.h"
#include "components/dom_distiller/core/task_tracker.h"

class GURL;

namespace dom_distiller {

class DistilledPagePrefs;
class Distiller;

// An interface for a dom_distiller ViewRequestDelegate that distills a URL and
// calls the given callback with the distilled HTML string and the images it
// contains.
class DistillerViewerInterface : public DomDistillerRequestViewBase {
 public:
  struct ImageInfo {
    // The url of the image.
    GURL url;
    // The image data as a string.
    std::string data;
  };
  using DistillationFinishedCallback =
      base::OnceCallback<void(const GURL& url,
                              const std::string& html,
                              const std::vector<ImageInfo>& images,
                              const std::string& title,
                              const std::string& csp_nonce)>;

  DistillerViewerInterface(PrefService* prefs)
      : DomDistillerRequestViewBase(new DistilledPagePrefs(prefs)) {}

  DistillerViewerInterface(const DistillerViewerInterface&) = delete;
  DistillerViewerInterface& operator=(const DistillerViewerInterface&) = delete;

  ~DistillerViewerInterface() override {}

  void OnArticleReady(
      const dom_distiller::DistilledArticleProto* article_proto) override = 0;

  void SendJavaScript(const std::string& buffer) override = 0;

  virtual std::string GetCspNonce() = 0;
};

// A very simple and naive implementation of the DistillerViewer.
class DistillerViewer : public DistillerViewerInterface {
 public:
  // Creates a `DistillerView` that will be used to distill `url`.
  // `callback` is called when distillation is finished with the protobuf
  // containing the distilled page.
  DistillerViewer(dom_distiller::DomDistillerService* distillerService,
                  PrefService* prefs,
                  const GURL& url,
                  DistillationFinishedCallback callback);

  // Creates a `DistillerView` without depending on the DomDistillerService.
  // Caller must provide `distiller_factory` and `page` which cannot be null.
  // `callback` is called when distillation is finished with the protobuf
  // containing the distilled page.
  DistillerViewer(dom_distiller::DistillerFactory* distiller_factory,
                  std::unique_ptr<dom_distiller::DistillerPage> page,
                  PrefService* prefs,
                  const GURL& url,
                  DistillationFinishedCallback callback);

  DistillerViewer(const DistillerViewer&) = delete;
  DistillerViewer& operator=(const DistillerViewer&) = delete;

  ~DistillerViewer() override;

  // DistillerViewerInterface implementation
  // Called by the distiller service when article is ready.
  void OnArticleReady(
      const dom_distiller::DistilledArticleProto* article_proto) override;

  void SendJavaScript(const std::string& buffer) override;

  std::string GetCspNonce() override;

 private:
  // Called by the distiller when article is ready.
  void OnDistillerFinished(
      std::unique_ptr<dom_distiller::DistilledArticleProto> distilled_article);

  // Called by the distiller when article is updated.
  void OnArticleDistillationUpdated(
      const dom_distiller::ArticleDistillationUpdate& article_update);

  // The url of the distilled page.
  const GURL url_;
  // JavaScript buffer.
  std::string js_buffer_;
  // CSP nonce value.
  std::string csp_nonce_;
  // Callback to run once distillation is complete.
  DistillationFinishedCallback callback_;
  // Keep reference of the distiller_ during distillation.
  std::unique_ptr<Distiller> distiller_;

  base::WeakPtrFactory<DistillerViewer> weak_ptr_factory_{this};
};

}  // namespace dom_distiller

#endif  // IOS_CHROME_BROWSER_DOM_DISTILLER_MODEL_DISTILLER_VIEWER_H_