diff options
Diffstat (limited to 'layout/generic/nsFlexContainerFrame.cpp')
| -rw-r--r-- | layout/generic/nsFlexContainerFrame.cpp | 138 |
1 files changed, 99 insertions, 39 deletions
diff --git a/layout/generic/nsFlexContainerFrame.cpp b/layout/generic/nsFlexContainerFrame.cpp index b61024324..4ecc7d877 100644 --- a/layout/generic/nsFlexContainerFrame.cpp +++ b/layout/generic/nsFlexContainerFrame.cpp @@ -33,6 +33,8 @@ typedef nsFlexContainerFrame::FlexItem FlexItem; typedef nsFlexContainerFrame::FlexLine FlexLine; typedef nsFlexContainerFrame::FlexboxAxisTracker FlexboxAxisTracker; typedef nsFlexContainerFrame::StrutInfo StrutInfo; +typedef nsFlexContainerFrame::CachedMeasuringReflowResult + CachedMeasuringReflowResult; static mozilla::LazyLogModule gFlexContainerLog("nsFlexContainerFrame"); @@ -1756,6 +1758,91 @@ nsFlexContainerFrame:: } } +/** + * A cached result for a measuring reflow. + * + * Right now we only need to cache the available size, the height and the + * ascent. This can be extended later if needed. + * + * The assumption here is that a given flex item measurement won't change until + * either the available size changes, or the flex container intrinsic size is + * marked as dirty (due to a style or DOM change). + * + * Caching it prevents us from doing exponential reflows in cases of deeply + * nested flex and scroll frames. + * + * We store them in the frame property table for simplicity. + */ +struct nsFlexContainerFrame::CachedMeasuringReflowResult +{ + LogicalSize mAvailableSize; + const nscoord mHeight; + const nscoord mAscent; + + CachedMeasuringReflowResult(const LogicalSize& aAvailableSize, + nscoord aHeight, + nscoord aAscent) + : mAvailableSize(aAvailableSize) + , mHeight(aHeight) + , mAscent(aAscent) + {} +}; + +NS_DECLARE_FRAME_PROPERTY_DELETABLE(CachedFlexMeasuringReflow, + CachedMeasuringReflowResult); + +const CachedMeasuringReflowResult& +nsFlexContainerFrame::MeasureAscentAndHeightForFlexItem( + FlexItem& aItem, + nsPresContext* aPresContext, + ReflowInput& aChildReflowInput) +{ + const auto availableSize = aChildReflowInput.AvailableSize(); + const FrameProperties props = aItem.Frame()->Properties(); + if (const auto* cachedResult = props.Get(CachedFlexMeasuringReflow())) { + if (cachedResult->mAvailableSize == availableSize) { + return *cachedResult; + } + } + + ReflowOutput childDesiredSize(aChildReflowInput); + nsReflowStatus childReflowStatus; + + const uint32_t flags = NS_FRAME_NO_MOVE_FRAME; + ReflowChild(aItem.Frame(), aPresContext, + childDesiredSize, aChildReflowInput, + 0, 0, flags, childReflowStatus); + aItem.SetHadMeasuringReflow(); + + // XXXdholbert Once we do pagination / splitting, we'll need to actually + // handle incomplete childReflowStatuses. But for now, we give our kids + // unconstrained available height, which means they should always complete. + MOZ_ASSERT(NS_FRAME_IS_COMPLETE(childReflowStatus), + "We gave flex item unconstrained available height, so it " + "should be complete"); + + // Tell the child we're done with its initial reflow. + // (Necessary for e.g. GetBaseline() to work below w/out asserting) + FinishReflowChild(aItem.Frame(), aPresContext, + childDesiredSize, &aChildReflowInput, 0, 0, flags); + + auto result = + new CachedMeasuringReflowResult(availableSize, + childDesiredSize.Height(), + childDesiredSize.BlockStartAscent()); + + props.Set(CachedFlexMeasuringReflow(), result); + return *result; +} + +/* virtual */ void +nsFlexContainerFrame::MarkIntrinsicISizesDirty() +{ + for (nsIFrame* childFrame : mFrames) { + childFrame->Properties().Delete(CachedFlexMeasuringReflow()); + } +} + nscoord nsFlexContainerFrame:: MeasureFlexItemContentHeight(nsPresContext* aPresContext, @@ -1783,27 +1870,15 @@ nsFlexContainerFrame:: childRIForMeasuringHeight.SetVResize(true); } - ReflowOutput childDesiredSize(childRIForMeasuringHeight); - nsReflowStatus childReflowStatus; - const uint32_t flags = NS_FRAME_NO_MOVE_FRAME; - ReflowChild(aFlexItem.Frame(), aPresContext, - childDesiredSize, childRIForMeasuringHeight, - 0, 0, flags, childReflowStatus); + const CachedMeasuringReflowResult& reflowResult = + MeasureAscentAndHeightForFlexItem(aFlexItem, aPresContext, + childRIForMeasuringHeight); - MOZ_ASSERT(NS_FRAME_IS_COMPLETE(childReflowStatus), - "We gave flex item unconstrained available height, so it " - "should be complete"); - - FinishReflowChild(aFlexItem.Frame(), aPresContext, - childDesiredSize, &childRIForMeasuringHeight, - 0, 0, flags); - - aFlexItem.SetHadMeasuringReflow(); - aFlexItem.SetAscent(childDesiredSize.BlockStartAscent()); + aFlexItem.SetAscent(reflowResult.mAscent); // Subtract border/padding in vertical axis, to get _just_ // the effective computed value of the "height" property. - nscoord childDesiredHeight = childDesiredSize.Height() - + nscoord childDesiredHeight = reflowResult.mHeight - childRIForMeasuringHeight.ComputedPhysicalBorderPadding().TopBottom(); return std::max(0, childDesiredHeight); @@ -3959,25 +4034,10 @@ nsFlexContainerFrame::SizeItemInCrossAxis( // whether any of its ancestors are being resized). aChildReflowInput.SetVResize(true); } - ReflowOutput childDesiredSize(aChildReflowInput); - nsReflowStatus childReflowStatus; - const uint32_t flags = NS_FRAME_NO_MOVE_FRAME; - ReflowChild(aItem.Frame(), aPresContext, - childDesiredSize, aChildReflowInput, - 0, 0, flags, childReflowStatus); - aItem.SetHadMeasuringReflow(); - - // XXXdholbert Once we do pagination / splitting, we'll need to actually - // handle incomplete childReflowStatuses. But for now, we give our kids - // unconstrained available height, which means they should always complete. - MOZ_ASSERT(NS_FRAME_IS_COMPLETE(childReflowStatus), - "We gave flex item unconstrained available height, so it " - "should be complete"); - // Tell the child we're done with its initial reflow. - // (Necessary for e.g. GetBaseline() to work below w/out asserting) - FinishReflowChild(aItem.Frame(), aPresContext, - childDesiredSize, &aChildReflowInput, 0, 0, flags); + // Potentially reflow the item, and get the sizing info. + const CachedMeasuringReflowResult& reflowResult = + MeasureAscentAndHeightForFlexItem(aItem, aPresContext, aChildReflowInput); // Save the sizing info that we learned from this reflow // ----------------------------------------------------- @@ -3989,7 +4049,7 @@ nsFlexContainerFrame::SizeItemInCrossAxis( // so we don't bother with making aAxisTracker pick the cross-axis component // for us.) nscoord crossAxisBorderPadding = aItem.GetBorderPadding().TopBottom(); - if (childDesiredSize.Height() < crossAxisBorderPadding) { + if (reflowResult.mHeight < crossAxisBorderPadding) { // Child's requested size isn't large enough for its border/padding! // This is OK for the trivial nsFrame::Reflow() impl, but other frame // classes should know better. So, if we get here, the child had better be @@ -4002,10 +4062,10 @@ nsFlexContainerFrame::SizeItemInCrossAxis( aItem.SetCrossSize(0); } else { // (normal case) - aItem.SetCrossSize(childDesiredSize.Height() - crossAxisBorderPadding); + aItem.SetCrossSize(reflowResult.mHeight - crossAxisBorderPadding); } - aItem.SetAscent(childDesiredSize.BlockStartAscent()); + aItem.SetAscent(reflowResult.mAscent); } void @@ -4295,7 +4355,7 @@ nsFlexContainerFrame::DoFlexLayout(nsPresContext* aPresContext, LogicalSize availSize = aReflowInput.ComputedSize(wm); availSize.BSize(wm) = NS_UNCONSTRAINEDSIZE; ReflowInput childReflowInput(aPresContext, aReflowInput, - item->Frame(), availSize); + item->Frame(), availSize); if (!sizeOverride) { // Directly override the computed main-size, by tweaking reflow state: if (aAxisTracker.IsMainAxisHorizontal()) { |