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-rw-r--r--layout/style/nsStyleStruct.cpp28
-rw-r--r--layout/style/test/mochitest.ini1
-rw-r--r--layout/style/test/test_dynamic_change_causing_reflow.html107
-rw-r--r--layout/style/test/test_viewport_scrollbar_causing_reflow.html125
4 files changed, 234 insertions, 27 deletions
diff --git a/layout/style/nsStyleStruct.cpp b/layout/style/nsStyleStruct.cpp
index eab11b80c..553239e0e 100644
--- a/layout/style/nsStyleStruct.cpp
+++ b/layout/style/nsStyleStruct.cpp
@@ -1629,28 +1629,11 @@ nsStylePosition::CalcDifference(const nsStylePosition& aNewData,
if (aOldStyleVisibility) {
bool isVertical = WritingMode(aOldStyleVisibility).IsVertical();
if (isVertical ? widthChanged : heightChanged) {
- // Block-size changes can affect descendant intrinsic sizes due to
- // replaced elements with percentage bsizes in descendants which
- // also have percentage bsizes. This is handled via
- // nsChangeHint_UpdateComputedBSize which clears intrinsic sizes
- // for frames that have such replaced elements.
- //
- // We need to use nsChangeHint_ClearAncestorIntrinsics for
- // block-size changes so we clear results of cached CSS Flex
- // measuring reflows.
- hint |= nsChangeHint_NeedReflow |
- nsChangeHint_UpdateComputedBSize |
- nsChangeHint_ReflowChangesSizeOrPosition |
- nsChangeHint_ClearAncestorIntrinsics;
+ hint |= nsChangeHint_ReflowHintsForBSizeChange;
}
if (isVertical ? heightChanged : widthChanged) {
- // None of our inline-size differences can affect descendant
- // intrinsic sizes and none of them need to force children to
- // reflow.
- hint |= nsChangeHint_AllReflowHints &
- ~(nsChangeHint_ClearDescendantIntrinsics |
- nsChangeHint_NeedDirtyReflow);
+ hint |= nsChangeHint_ReflowHintsForISizeChange;
}
} else {
if (widthChanged || heightChanged) {
@@ -3263,8 +3246,6 @@ nsStyleDisplay::CalcDifference(const nsStyleDisplay& aNewData) const
|| mDisplay != aNewData.mDisplay
|| mContain != aNewData.mContain
|| (mFloat == StyleFloat::None) != (aNewData.mFloat == StyleFloat::None)
- || mOverflowX != aNewData.mOverflowX
- || mOverflowY != aNewData.mOverflowY
|| mScrollBehavior != aNewData.mScrollBehavior
|| mScrollSnapTypeX != aNewData.mScrollSnapTypeX
|| mScrollSnapTypeY != aNewData.mScrollSnapTypeY
@@ -3276,6 +3257,11 @@ nsStyleDisplay::CalcDifference(const nsStyleDisplay& aNewData) const
hint |= nsChangeHint_ReconstructFrame;
}
+ if (mOverflowX != aNewData.mOverflowX
+ || mOverflowY != aNewData.mOverflowY) {
+ hint |= nsChangeHint_CSSOverflowChange;
+ }
+
/* Note: When mScrollBehavior, mScrollSnapTypeX, mScrollSnapTypeY,
* mScrollSnapPointsX, mScrollSnapPointsY, or mScrollSnapDestination are
* changed, nsChangeHint_NeutralChange is not sufficient to enter
diff --git a/layout/style/test/mochitest.ini b/layout/style/test/mochitest.ini
index 406c6f901..8182691ca 100644
--- a/layout/style/test/mochitest.ini
+++ b/layout/style/test/mochitest.ini
@@ -295,6 +295,7 @@ skip-if = toolkit == 'android'
[test_variables.html]
support-files = support/external-variable-url.css
[test_video_object_fit.html]
+[test_viewport_scrollbar_causing_reflow.html]
[test_viewport_units.html]
[test_visited_image_loading.html]
skip-if = toolkit == 'android' #TIMED_OUT
diff --git a/layout/style/test/test_dynamic_change_causing_reflow.html b/layout/style/test/test_dynamic_change_causing_reflow.html
index a941191f6..a5bb3045c 100644
--- a/layout/style/test/test_dynamic_change_causing_reflow.html
+++ b/layout/style/test/test_dynamic_change_causing_reflow.html
@@ -95,6 +95,90 @@ const gTestcases = [
expectReflow: true,
},
+ // * Changing 'overflow' on <body> should cause reflow,
+ // but not frame reconstruction
+ {
+ elem: document.body,
+ /* beforeStyle: implicitly 'overflow:visible' */
+ afterStyle: "overflow: hidden",
+ expectConstruction: false,
+ expectReflow: true,
+ },
+ {
+ elem: document.body,
+ /* beforeStyle: implicitly 'overflow:visible' */
+ afterStyle: "overflow: scroll",
+ expectConstruction: false,
+ expectReflow: true,
+ },
+ {
+ elem: document.body,
+ beforeStyle: "overflow: hidden",
+ afterStyle: "overflow: auto",
+ expectConstruction: false,
+ expectReflow: true,
+ },
+ {
+ elem: document.body,
+ beforeStyle: "overflow: hidden",
+ afterStyle: "overflow: scroll",
+ expectConstruction: false,
+ expectReflow: true,
+ },
+ {
+ elem: document.body,
+ beforeStyle: "overflow: hidden",
+ afterStyle: "overflow: visible",
+ expectConstruction: false,
+ expectReflow: true,
+ },
+ {
+ elem: document.body,
+ beforeStyle: "overflow: auto",
+ afterStyle: "overflow: hidden",
+ expectConstruction: false,
+ expectReflow: true,
+ },
+ {
+ elem: document.body,
+ beforeStyle: "overflow: visible",
+ afterStyle: "overflow: hidden",
+ expectConstruction: false,
+ expectReflow: true,
+ },
+
+ // * Changing 'overflow' on <html> should cause reflow,
+ // but not frame reconstruction
+ {
+ elem: document.documentElement,
+ /* beforeStyle: implicitly 'overflow:visible' */
+ afterStyle: "overflow: auto",
+ expectConstruction: false,
+ expectReflow: true,
+ },
+ {
+ elem: document.documentElement,
+ beforeStyle: "overflow: visible",
+ afterStyle: "overflow: auto",
+ expectConstruction: false,
+ expectReflow: true,
+ },
+
+ // * Setting 'overflow' on arbitrary node should cause reflow as well as
+ // frame reconstruction
+ {
+ /* beforeStyle: implicitly 'overflow:visible' */
+ afterStyle: "overflow: auto",
+ expectConstruction: true,
+ expectReflow: true,
+ },
+ {
+ beforeStyle: "overflow: auto",
+ afterStyle: "overflow: visible",
+ expectConstruction: true,
+ expectReflow: true,
+ },
+
// * Changing 'display' should cause frame construction and reflow.
{
beforeStyle: "display: inline",
@@ -135,23 +219,34 @@ function runOneTest(aTestcase)
return;
}
+ // Figure out which element we'll be tweaking (defaulting to gElem)
+ let elem = aTestcase.elem ?
+ aTestcase.elem : gElem;
+
+ // Verify that 'style' attribute is unset (avoid causing ourselves trouble):
+ if (elem.hasAttribute("style")) {
+ ok(false,
+ "test element has 'style' attribute already set! We're going to stomp " +
+ "on whatever's there when we clean up...");
+ }
+
// Set the "before" style, and compose the first part of the message
// to be used in our "is"/"isnot" invocations:
let msgPrefix = "Changing style ";
if (aTestcase.beforeStyle) {
- gElem.setAttribute("style", aTestcase.beforeStyle);
+ elem.setAttribute("style", aTestcase.beforeStyle);
msgPrefix += "from '" + aTestcase.beforeStyle + "' ";
}
- msgPrefix += "to '" + aTestcase.afterStyle + "' ";
+ msgPrefix += "on " + elem.nodeName + " ";
// Establish initial counts:
- let unusedVal = gElem.offsetHeight; // flush layout
+ let unusedVal = elem.offsetHeight; // flush layout
let origFramesConstructed = gUtils.framesConstructed;
let origFramesReflowed = gUtils.framesReflowed;
// Make the change and flush:
- gElem.setAttribute("style", aTestcase.afterStyle);
- unusedVal = gElem.offsetHeight; // flush layout
+ elem.setAttribute("style", aTestcase.afterStyle);
+ unusedVal = elem.offsetHeight; // flush layout
// Make our is/isnot assertions about whether things should have changed:
checkFinalCount(gUtils.framesConstructed, origFramesConstructed,
@@ -162,7 +257,7 @@ function runOneTest(aTestcase)
"reflow");
// Clean up!
- gElem.removeAttribute("style");
+ elem.removeAttribute("style");
}
gTestcases.forEach(runOneTest);
diff --git a/layout/style/test/test_viewport_scrollbar_causing_reflow.html b/layout/style/test/test_viewport_scrollbar_causing_reflow.html
new file mode 100644
index 000000000..dfd7ec450
--- /dev/null
+++ b/layout/style/test/test_viewport_scrollbar_causing_reflow.html
@@ -0,0 +1,125 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1367568
+-->
+<head>
+ <meta charset="utf-8">
+ <title>Test for Bug 1367568</title>
+ <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+ <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=">Mozilla Bug 1367568</a>
+<div id="content">
+ <!-- Some fixed-width divs that we shouldn't have to reflow when the viewport
+ changes: -->
+ <div style="width: 100px">
+ fixed-width
+ <div>(child)</div>
+ </div>
+ <div style="position: absolute; width: 150px">
+ abs-fixed-width
+ <div>(child)</div>
+ </div>
+</div>
+<pre id="test">
+<script type="application/javascript">
+"use strict";
+
+/** Test for Bug 1367568 **/
+
+/**
+ * This test verifies that "overflow" changes on the <body> don't cause
+ * an unnecessarily large amount of reflow.
+ */
+
+// Vars used in setStyleAndMeasure that we really only have to look up once:
+const gUtils = SpecialPowers.getDOMWindowUtils(window);
+
+function setStyleAndMeasure(initialStyle, finalStyle) {
+ is(document.body.style.length, 0,
+ "Bug in test - body should start with empty style");
+ let unusedVal = document.body.offsetHeight; // flush layout
+ let constructCount = gUtils.framesConstructed;
+
+ document.body.style = initialStyle;
+ unusedVal = document.body.offsetHeight; // flush layout
+ let reflowCountBeforeTweak = gUtils.framesReflowed;
+
+ document.body.style = finalStyle;
+ unusedVal = document.body.offsetHeight; // flush layout
+ let reflowCountAfterTweak = gUtils.framesReflowed;
+
+ // Clean up:
+ document.body.style = "";
+
+ is(gUtils.framesConstructed, constructCount,
+ "Style tweak shouldn't have triggered frame construction");
+
+ // ...and return the delta:
+ return reflowCountAfterTweak - reflowCountBeforeTweak;
+}
+
+function main() {
+ // First, we sanity-check that our measurement make sense -- if we leave
+ // styles unchanged, we should measure no frames being reflowed:
+ let count = setStyleAndMeasure("width: 50px; height: 80px",
+ "width: 50px; height: 80px");
+ is(count, 0,
+ "Shouldn't reflow anything when we leave 'width' & 'height' unchanged");
+
+ // Now: see how many frames are reflowed when the "width" & "height" change.
+ // We'll use this as the reference when measuring reflow counts for various
+ // changes to "overflow" below.
+ count = setStyleAndMeasure("width: 50px; height: 80px",
+ "width: 90px; height: 60px");
+ ok(count > 0,
+ "Should reflow some frames when 'width' & 'height' change");
+
+ // Expected maximum number of frames reflowed for "overflow" changes
+ // (+2 is to allow for reflowing scrollbars themselves):
+ const expectedMax = count + 2;
+
+ // Shared ending for messages in all ok() checks below:
+ const messageSuffix =
+ " shouldn't be greater than count for tweaking width/height on body (" +
+ expectedMax + ")";
+
+ // OK, here is where the relevant tests actually begin!!
+ // See how many frames we reflow for various tweaks to "overflow" on
+ // the body -- we expect the count to be no larger than |expectedMax|.
+ count = setStyleAndMeasure("", "overflow: scroll");
+ ok(count <= expectedMax,
+ "Reflow count when setting 'overflow: scroll' on body (" + count + ")" +
+ messageSuffix);
+
+ count = setStyleAndMeasure("", "overflow: hidden");
+ ok(count <= expectedMax,
+ "Reflow count when setting 'overflow: hidden' on body (" + count + ")" +
+ messageSuffix);
+
+ // Test removal of "overflow: scroll":
+ count = setStyleAndMeasure("overflow: scroll", "");
+ ok(count <= expectedMax,
+ "Reflow count when removing 'overflow: scroll' from body (" + count + ")" +
+ messageSuffix);
+
+ count = setStyleAndMeasure("overflow: hidden", "");
+ ok(count <= expectedMax,
+ "Reflow count when removing 'overflow: hidden' from body (" + count + ")" +
+ messageSuffix);
+
+ // Test change between two non-'visible' overflow values:
+ count = setStyleAndMeasure("overflow: scroll", "overflow: hidden");
+ ok(count <= expectedMax,
+ "Reflow count when changing 'overflow' on body (" + count + ")" +
+ messageSuffix);
+}
+
+main();
+
+</script>
+</pre>
+</body>
+</html>