Changeset 84296 in webkit

Timestamp:

Apr 19, 2011, 2:30:54 PM (14 years ago)

Author:

Beth Dakin

Message:

​https://bugs.webkit.org/show_bug.cgi?id=57898
REGRESSION (r82185): Scroll position not restored on navigation back to a page in
the page cache
-and corresponding-
<rdar://problem/9226652>

Reviewed by Maciej Stachowiak.

Source/WebCore:

Setting the contentsSize of a ScrollView to (0, 0) necessarily causes the scroll
position to be lost. (The scroll position is computed based on the
visibleContentSize.) This patch provides a mechanism to cache the current scroll
position, and then the HistoryController accesses only the cached position rather
than calling scrollPosition() which does a computation based on the
visibleContentSize.

• loader/HistoryController.cpp:

(WebCore::HistoryController::saveScrollPositionAndViewStateToItem):

• page/FrameView.cpp:

(WebCore::FrameView::resetScrollbarsAndClearContentsSize):

• platform/ScrollView.h:

(WebCore::ScrollView::cacheCurrentScrollPosition):
(WebCore::ScrollView::cachedScrollPosition):

LayoutTests:

• fast/loader/resources/empty-document-goes-back.html: Added.
• fast/loader/scroll-position-restored-on-back-expected.txt: Added.
• fast/loader/scroll-position-restored-on-back.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/loader/resources/empty-document-goes-back.html (added)
• LayoutTests/fast/loader/scroll-position-restored-on-back-expected.txt (added)
• LayoutTests/fast/loader/scroll-position-restored-on-back.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/loader/HistoryController.cpp (modified) (1 diff)
• Source/WebCore/page/FrameView.cpp (modified) (1 diff)
• Source/WebCore/platform/ScrollView.h (modified) (2 diffs)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2011-04-19  Beth Dakin  <bdakin@apple.com>
+
+        Reviewed by Maciej Stachowiak.
+
+        https://bugs.webkit.org/show_bug.cgi?id=57898
+        REGRESSION (r82185): Scroll position not restored on navigation back to a page in 
+        the page cache
+        -and corresponding-
+        <rdar://problem/9226652>
+
+        * fast/loader/resources/empty-document-goes-back.html: Added.
+        * fast/loader/scroll-position-restored-on-back-expected.txt: Added.
+        * fast/loader/scroll-position-restored-on-back.html: Added.
+
 2011-04-19  Ryosuke Niwa  <rniwa@webkit.org>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2011-04-19  Beth Dakin  <bdakin@apple.com>
+
+        Reviewed by Maciej Stachowiak.
+
+        https://bugs.webkit.org/show_bug.cgi?id=57898
+        REGRESSION (r82185): Scroll position not restored on navigation back to a page in 
+        the page cache
+        -and corresponding-
+        <rdar://problem/9226652>
+
+        Setting the contentsSize of a ScrollView to (0, 0) necessarily causes the scroll 
+        position to be lost. (The scroll position is computed based on the 
+        visibleContentSize.) This patch provides a mechanism to cache the current scroll 
+        position, and then the HistoryController accesses only the cached position rather 
+        than calling scrollPosition() which does a computation based on the 
+        visibleContentSize. 
+
+        * loader/HistoryController.cpp:
+        (WebCore::HistoryController::saveScrollPositionAndViewStateToItem):
+        * page/FrameView.cpp:
+        (WebCore::FrameView::resetScrollbarsAndClearContentsSize):
+        * platform/ScrollView.h:
+        (WebCore::ScrollView::cacheCurrentScrollPosition):
+        (WebCore::ScrollView::cachedScrollPosition):
+
 2011-04-19  Renata Hodovan  <reni@webkit.org>
 

trunk/Source/WebCore/loader/HistoryController.cpp

@@ -80 +80 @@
         return;
         
-    item->setScrollPoint(m_frame->view()->scrollPosition());
+    item->setScrollPoint(m_frame->view()->cachedScrollPosition());
     item->setPageScaleFactor(m_frame->pageScaleFactor());
     

trunk/Source/WebCore/page/FrameView.cpp

@@ -259 +259 @@
 void FrameView::resetScrollbarsAndClearContentsSize()
 {
+    // Since the contents size is being cleared, the scroll position will lost as a consequence.
+    // Cache the scroll position so it can be restored by the page cache if necessary. 
+    cacheCurrentScrollPosition();
+
     resetScrollbars();
 

trunk/Source/WebCore/platform/ScrollView.h

@@ -180 +180 @@
     IntSize overhangAmount() const;
 
+    void cacheCurrentScrollPosition() { m_cachedScrollPosition = scrollPosition(); }
+    IntPoint cachedScrollPosition() const { return m_cachedScrollPosition; }
+
     // Functions for scrolling the view.
     void setScrollPosition(const IntPoint&);
@@ -339 +342 @@
     IntRect m_actualVisibleContentRect;
     IntSize m_scrollOffset; // FIXME: Would rather store this as a position, but we will wait to make this change until more code is shared.
+    IntPoint m_cachedScrollPosition;
     IntSize m_fixedLayoutSize;
     IntSize m_contentsSize;