// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_DOM_DISTILLER_CORE_DISTILLER_PAGE_H_
#define COMPONENTS_DOM_DISTILLER_CORE_DISTILLER_PAGE_H_
#include <string>
#include "base/memory/scoped_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/values.h"
#include "url/gurl.h"
namespace dom_distiller {
// Injects JavaScript into a page, and uses it to extract and return long-form
// content. The class can be reused to load and distill multiple pages,
// following the state transitions described along with the class's states.
class DistillerPage {
public:
class Delegate {
public:
virtual ~Delegate() {}
virtual void OnLoadURLDone() {}
virtual void OnExecuteJavaScriptDone(const GURL& page_url,
const base::Value* value) {}
};
// Specifies the Delegate that owns this distiller page.
explicit DistillerPage(const base::WeakPtr<Delegate>& delegate);
virtual ~DistillerPage();
// Initializes a |DistillerPage|. It must be called before any
// other functions, and must only be called once.
void Init();
// Loads a URL. |OnLoadURLDone| is called when the load completes or fails.
// May be called when the distiller is idle or a page is available.
void LoadURL(const GURL& url);
virtual void OnLoadURLDone();
virtual void OnLoadURLFailed();
// Injects and executes JavaScript in the context of a loaded page. |LoadURL|
// must complete before this function is called. May be called only when
// a page is available.
void ExecuteJavaScript(const std::string& script);
// Called when the JavaScript execution completes. |page_url| is the url of
// the distilled page. |value| contains data returned by the script.
virtual void OnExecuteJavaScriptDone(const GURL& page_url,
const base::Value* value);
protected:
enum State {
// No context has yet been set in which to load or distill a page.
NO_CONTEXT,
// The page distiller has been initialized and is idle.
IDLE,
// A page is currently loading.
LOADING_PAGE,
// A page has loaded within the specified context.
PAGE_AVAILABLE,
// There was an error processing the page.
PAGELOAD_FAILED,
// JavaScript is executing within the context of the page. When the
// JavaScript completes, the state will be returned to |PAGE_AVAILABLE|.
EXECUTING_JAVASCRIPT
};
// Called by |Init| to do plaform-specific initialization work set up an
// environment in which a page can be loaded.
virtual void InitImpl() = 0;
// Called by |LoadURL| to carry out platform-specific instructions to load a
// page.
virtual void LoadURLImpl(const GURL& gurl) = 0;
// Called by |ExecuteJavaScript| to carry out platform-specific instructions
// to inject and execute JavaScript within the context of the loaded page.
virtual void ExecuteJavaScriptImpl(const std::string& script) = 0;
// The current state of the |DistillerPage|, initially |NO_CONTEXT|.
State state_;
private:
// The pointer to the delegate that owns this distiller page.
base::WeakPtr<Delegate> delegate_;
DISALLOW_COPY_AND_ASSIGN(DistillerPage);
};
// Factory for generating a |DistillerPage|.
class DistillerPageFactory {
public:
virtual ~DistillerPageFactory();
virtual scoped_ptr<DistillerPage> CreateDistillerPage(
const base::WeakPtr<DistillerPage::Delegate>& delegate) const = 0;
};
} // namespace dom_distiller
#endif // COMPONENTS_DOM_DISTILLER_CORE_DISTILLER_PAGE_H_