| // Copyright 2017 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 IOS_CHROME_BROWSER_WEB_PAGE_PLACEHOLDER_TAB_HELPER_H_ |
| #define IOS_CHROME_BROWSER_WEB_PAGE_PLACEHOLDER_TAB_HELPER_H_ |
| |
| #import <UIKit/UIKit.h> |
| |
| #include "base/macros.h" |
| #import "ios/chrome/browser/ui/elements/top_aligned_image_view.h" |
| #include "ios/web/public/web_state_observer.h" |
| #import "ios/web/public/web_state_user_data.h" |
| |
| // Displays placeholder to cover what WebState is actually displaying. Can be |
| // used to display the cached image of the web page during the Tab restoration. |
| // The placeholder is added as a subview on the WebState's view. Properly |
| // positioning the placeholder requires that the WebState's view is in a view |
| // hierarchy that has the Content Area named guide. |
| class PagePlaceholderTabHelper |
| : public web::WebStateUserData<PagePlaceholderTabHelper>, |
| public web::WebStateObserver { |
| public: |
| ~PagePlaceholderTabHelper() override; |
| |
| // Displays placeholder between DidStartNavigation and PageLoaded |
| // WebStateObserver callbacks. If navigation takes too long, then placeholder |
| // will be removed before navigation is finished. The placeholder is only ever |
| // displayed when the tab is visible. |
| void AddPlaceholderForNextNavigation(); |
| |
| // Cancels displaying placeholder during the next navigation. If placeholder |
| // is displayed, then it is removed. |
| void CancelPlaceholderForNextNavigation(); |
| |
| // true if placeholder is currently being displayed. |
| bool displaying_placeholder() const { return displaying_placeholder_; } |
| |
| // true if placeholder will be displayed between DidStartNavigation and |
| // PageLoaded WebStateObserver callbacks. |
| bool will_add_placeholder_for_next_navigation() const { |
| return add_placeholder_for_next_navigation_; |
| } |
| |
| private: |
| friend class web::WebStateUserData<PagePlaceholderTabHelper>; |
| |
| explicit PagePlaceholderTabHelper(web::WebState* web_state); |
| |
| // web::WebStateObserver overrides: |
| void WasShown(web::WebState* web_state) override; |
| void WasHidden(web::WebState* web_state) override; |
| void DidStartNavigation(web::WebState* web_state, |
| web::NavigationContext* navigation_context) override; |
| void PageLoaded( |
| web::WebState* web_state, |
| web::PageLoadCompletionStatus load_completion_status) override; |
| void WebStateDestroyed(web::WebState* web_state) override; |
| |
| void AddPlaceholder(); |
| void RemovePlaceholder(); |
| |
| // Adds the given |snapshot| image to the |web_state_|'s view. The |
| // |web_state_|'s view must be visible, and it must be in a view hierarchy |
| // that has the Content Area named guide. |
| void DisplaySnapshotImage(UIImage* snapshot); |
| |
| // WebState this tab helper is attached to. |
| web::WebState* web_state_ = nullptr; |
| |
| // View used to display the placeholder. |
| TopAlignedImageView* placeholder_view_ = nil; |
| |
| // true if placeholder is currently being displayed. |
| bool displaying_placeholder_ = false; |
| |
| // true if placeholder must be displayed during the next navigation. |
| bool add_placeholder_for_next_navigation_ = false; |
| |
| base::WeakPtrFactory<PagePlaceholderTabHelper> weak_factory_; |
| |
| WEB_STATE_USER_DATA_KEY_DECL(); |
| |
| DISALLOW_COPY_AND_ASSIGN(PagePlaceholderTabHelper); |
| }; |
| |
| #endif // IOS_CHROME_BROWSER_WEB_PAGE_PLACEHOLDER_TAB_HELPER_H_ |