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// Copyright (c) 2011 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.
#pragma once
#include <string>
#include "base/memory/weak_ptr.h"
#include "chrome/common/translate_errors.h"
#include "content/public/renderer/render_view_observer.h"
namespace WebKit {
class WebDocument;
class WebFrame;
// This class deals with page translation.
// There is one TranslateHelper per RenderView.
class TranslateHelper : public content::RenderViewObserver {
explicit TranslateHelper(content::RenderView* render_view);
virtual ~TranslateHelper();
// Informs us that the page's text has been extracted.
void PageCaptured(const string16& contents);
// The following methods are protected so they can be overridden in
// unit-tests.
void OnTranslatePage(int page_id,
const std::string& translate_script,
const std::string& source_lang,
const std::string& target_lang);
void OnRevertTranslation(int page_id);
// Returns true if the translate library is available, meaning the JavaScript
// has already been injected in that page.
virtual bool IsTranslateLibAvailable();
// Returns true if the translate library has been initialized successfully.
virtual bool IsTranslateLibReady();
// Returns true if the translation script has finished translating the page.
virtual bool HasTranslationFinished();
// Returns true if the translation script has reported an error performing the
// translation.
virtual bool HasTranslationFailed();
// Starts the translation by calling the translate library. This method
// should only be called when the translate script has been injected in the
// page. Returns false if the call failed immediately.
virtual bool StartTranslation();
// Asks the Translate element in the page what the language of the page is.
// Can only be called if a translation has happened and was successful.
// Returns the language code on success, an empty string on failure.
virtual std::string GetOriginalPageLanguage();
// Used in unit-tests. Makes the various tasks be posted immediately so that
// the tests don't have to wait before checking states.
virtual bool DontDelayTasks();
// Returns whether the page associated with |document| is a candidate for
// translation. Some pages can explictly specify (via a meta-tag) that they
// should not be translated.
static bool IsPageTranslatable(WebKit::WebDocument* document);
// Returns the language specified in the language meta tag of |document|, or
// an empty string if no such tag was found.
// The tag may specify several languages, the first one is returned.
// Example of such meta-tag:
// <meta http-equiv="content-language" content="en, fr">
static std::string GetPageLanguageFromMetaTag(WebKit::WebDocument* document);
// Returns the ISO 639_1 language code of the specified |text|, or 'unknown'
// if it failed.
static std::string DetermineTextLanguage(const string16& text);
// RenderViewObserver implementation.
virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
// Cancels any translation that is currently being performed. This does not
// revert existing translations.
void CancelPendingTranslation();
// Checks if the current running page translation is finished or errored and
// notifies the browser accordingly. If the translation has not terminated,
// posts a task to check again later.
void CheckTranslateStatus();
// Executes the JavaScript code in |script| in the main frame of
// |render_view_host_|.
// Returns true if the code was executed successfully.
bool ExecuteScript(const std::string& script);
// Executes the JavaScript code in |script| in the main frame of
// |render_view_host_|, and sets |value| to the boolean returned by the script
// evaluation. Returns true if the script was run successfully and returned
// a boolean, false otherwise
bool ExecuteScriptAndGetBoolResult(const std::string& script, bool* value);
// Executes the JavaScript code in |script| in the main frame of
// |render_view_host_|, and sets |value| to the string returned by the script
// evaluation. Returns true if the script was run successfully and returned
// a string, false otherwise
bool ExecuteScriptAndGetStringResult(const std::string& script,
std::string* value);
// Called by TranslatePage to do the actual translation. |count| is used to
// limit the number of retries.
void TranslatePageImpl(int count);
// Sends a message to the browser to notify it that the translation failed
// with |error|.
void NotifyBrowserTranslationFailed(TranslateErrors::Type error);
// Convenience method to access the main frame. Can return NULL, typically
// if the page is being closed.
WebKit::WebFrame* GetMainFrame();
// The states associated with the current translation.
bool translation_pending_;
int page_id_;
std::string source_lang_;
std::string target_lang_;
// Method factory used to make calls to TranslatePageImpl.
base::WeakPtrFactory<TranslateHelper> weak_method_factory_;