// Copyright 2019 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_READING_LIST_MODEL_OFFLINE_PAGE_TAB_HELPER_H_
#define IOS_CHROME_BROWSER_READING_LIST_MODEL_OFFLINE_PAGE_TAB_HELPER_H_
#include <memory>
#include <string>
#import "base/memory/raw_ptr.h"
#import "components/reading_list/core/reading_list_model_observer.h"
#import "ios/web/public/web_state_observer.h"
#import "ios/web/public/web_state_user_data.h"
namespace base {
class RepeatingTimer;
}
namespace web {
class NavigationContext;
class WebState;
} // namespace web
class ReadingListModel;
// Responsible for presenting distilled version of page in the attached
// WebState. This TabHelper will replace the DOM of the WKWebView with the
// distilled version stored on disk. It will also update the URL of the
// navigation back to the online URL to make sure online page is loaded on
// reload. The distilled page will be displayed if:
// - The load is slow (possibly due to poor network conditions).
// - The load has failed (possibly because the device does not have internet).
// It is possible to trigger a page load failure to load the distilled
// version of `url` by loading chrome://offline?entryURL=url.
class OfflinePageTabHelper : public web::WebStateUserData<OfflinePageTabHelper>,
public web::WebStateObserver,
ReadingListModelObserver {
public:
~OfflinePageTabHelper() override;
// Returns true if distilled version is currently being presented.
bool presenting_offline_page() const { return presenting_offline_page_; }
// Returns true if reading list model has processed entry for the given url.
bool HasDistilledVersionForOnlineUrl(const GURL& url) const;
// Returns true if offline page can handle this url loading.
bool CanHandleErrorLoadingURL(const GURL& url) const;
// Presents distilled version of the page if reading list model has processed
// entry for the given url.
void LoadOfflinePage(const GURL& url);
private:
friend class web::WebStateUserData<OfflinePageTabHelper>;
OfflinePageTabHelper(web::WebState* web_state, ReadingListModel* model);
// Detach from both WebState and ReadingListModel if any of these two becomes
// unavailable.
void Detach();
// WebStateObserver:
void DidStartNavigation(web::WebState* web_state,
web::NavigationContext* context) override;
void DidFinishNavigation(web::WebState* web_state,
web::NavigationContext* navigation_context) override;
// Makes a simulated request to `url` by loading `data` as HTML or PDF,
// depending on `is_pdf`.
void LoadOfflineData(web::WebState* web_state,
const GURL& url,
bool is_pdf,
const std::string& data);
void PageLoaded(
web::WebState* web_state,
web::PageLoadCompletionStatus load_completion_status) override;
void WebStateDestroyed(web::WebState* web_state) override;
// ReadingListModelObserver:
void ReadingListModelLoaded(const ReadingListModel* model) override;
void ReadingListModelBeingDeleted(const ReadingListModel* model) override;
// Presents distilled version of the page if reading list model has processed
// entry for the given url.
// Note: This method will replace the last committed navigation item. If the
// pending navigation was not yet committed, it returns immediately and is
// noop. In these conditions, the offline page will be presented on navigation
// commit.
// TODO(crbug.com/40615979): handle uncommitted navigations.
void PresentOfflinePageForOnlineUrl(const GURL& url);
// Starts repeating `timer_` which will fire `CheckLoadingProgress` method.
void StartCheckingLoadingProgress(const GURL& url);
// Stops repeating `timer_`.
void StopCheckingLoadingProgress();
// Tracks the page loading progress and presents distilled version of the page
// if the following conditions are met:
// - the page load is slow
// - the loading progress did not reach 75%
// - reading list model has processed entry for the given url
void CheckLoadingProgress(const GURL& url);
// Loads `data` into the web_state() if `offline_navigation` is equal to
// `last_navigation_started_`. `extension` is used to determine the MIMEType
// of `data`.
void LoadData(int offline_navigation,
const GURL& url,
const std::string& extension,
const std::string& data);
// Returns the URL of the Reading List entry given a navigation URL.
GURL GetOnlineURLFromNavigationURL(const GURL& url) const;
// Injects some JS to replace the current page with `url` and reload the page.
void ReplaceLocationUrlAndReload(const GURL& url);
raw_ptr<web::WebState> web_state_ = nullptr;
raw_ptr<ReadingListModel> reading_list_model_ = nullptr;
// The initial URL of the navigation. This URL will not follow the
// redirections so it may be different from GetLastCommittedURL.
GURL initial_navigation_url_;
// true if distilled version is currently being displayed.
bool presenting_offline_page_ = false;
// Timer started with navigation. When this timer fires, this tab helper may
// attempt to present distilled version of the page.
std::unique_ptr<base::RepeatingTimer> timer_;
// Number of times when `timer_` fired. Used to determine if the load progress
// is slow and it's actually time to present distilled version of the page.
int try_number_ = 0;
// A counter of the navigation sterted in web_state. Is used as an ID for the
// navigation that triggered an offline page presentation.
long last_navigation_started_ = 0;
// The URL of the offline page the is presented by this TabHelper.
// Is used to ignore the navigation triggered by WebState::LoadData.
GURL offline_navigation_triggered_;
// Whether the page could not be loaded, either because it was too slow, or
// because an error occurred.
bool loading_slow_or_failed_ = false;
// Whether the navigation for which this tab helper started the timer has been
// committed.
bool navigation_committed_ = false;
// Whether the latest navigation started for this tab helper was initiated
// with chrome://offline URL.
bool is_offline_navigation_ = false;
// Whether the latest navigation started for this tab helper was a reload.
bool is_reload_navigation_ = false;
// Whether the latest navigation started for this tab helper is a new one.
bool is_new_navigation_ = false;
// Some parameters of the latest navigation started observed by this tab
// helper.
ui::PageTransition navigation_transition_type_ = ui::PAGE_TRANSITION_FIRST;
bool navigation_is_renderer_initiated_ = false;
// On next navigation, don't reload the online page.
bool dont_reload_online_on_next_navigation_ = false;
// Whether a reload navigation has just been triggered.
bool reloading_from_offline_ = false;
WEB_STATE_USER_DATA_KEY_DECL();
// Member variables should appear before the WeakPtrFactory, to ensure
// that any WeakPtrs to OfflinePageTabHelper are invalidated before its
// members variable's destructors are executed, rendering them invalid.
base::WeakPtrFactory<OfflinePageTabHelper> weak_factory_{this};
};
#endif // IOS_CHROME_BROWSER_READING_LIST_MODEL_OFFLINE_PAGE_TAB_HELPER_H_
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