tor-browser

commit 298bf96b4060eda1025742ddec94e44e1ff926d6
parent e81a02b99aae84128329ba94f829efda821fa642
Author: Ting-Yu Lin <tlin@mozilla.com>
Date:   Mon,  8 Dec 2025 17:10:52 +0000

Bug 1985982 - Update comments in ReflowInput::InitAbsoluteConstraints(). r=layout-reviewers,emilio

Delete legacy XXX comments. It is true that we always compute the inline-size in
`nsIFrame::ComputeSize()`. However, we compute the offsets in the containing
block's writing mode. In orthogonal flow, the inline-size in containing block's
writing mode is the block-size of `mFrame`, which might still be unconstrained.

Note: changing `iSizeIsAuto` to `computedSize.ISize(cbwm)` could introduce test
failures in
`testing/web-platform/tests/css/css-position/position-absolute-table-001.html`,
because the table wrapper always has `auto` width/height, but
`nsTableWrapperFrame::ComputeAutoSize()` can resolve a definite width/height,
which acts as min-width/min-height. So the offsets are only correct when we
resolve them after reflowing the table.

Differential Revision: https://phabricator.services.mozilla.com/D275369

Diffstat:
M
layout/generic/ReflowInput.cpp
 | 
23
++++++-----------------

1 file changed, 6 insertions(+), 17 deletions(-)
diff --git a/layout/generic/ReflowInput.cpp b/layout/generic/ReflowInput.cpp
@@ -1874,9 +1874,6 @@ void ReflowInput::InitAbsoluteConstraints(const ReflowInput* aCBReflowInput,
         size.mAspectRatioUsage == nsIFrame::AspectRatioUsage::ToComputeBSize;
   }
 
-  // XXX Now that we have ComputeSize, can we condense many of the
-  // branches off of widthIsAuto?
-
   LogicalMargin margin = ComputedLogicalMargin(cbwm);
   const LogicalMargin borderPadding = ComputedLogicalBorderPadding(cbwm);
 
@@ -1903,13 +1900,9 @@ void ReflowInput::InitAbsoluteConstraints(const ReflowInput* aCBReflowInput,
   mFlags.mDeferAutoMarginComputation =
       nonZeroAutoMarginOnUnconstrainedSize || hasIntrinsicKeywordForBSize;
   if (iStartIsAuto) {
-    // We know 'right' is not 'auto' anymore thanks to the hypothetical
-    // box code above.
-    // Solve for 'left'.
+    // We know 'inset-inline-end' is not 'auto' anymore thanks to the
+    // hypothetical box code above. Solve for 'inset-inline-start'.
     if (iSizeIsAuto) {
-      // XXXldb This, and the corresponding code in
-      // AbsoluteContainingBlock.cpp, could probably go away now that
-      // we always compute widths.
       offsets.IStart(cbwm) = NS_AUTOOFFSET;
     } else {
       offsets.IStart(cbwm) = aCBSize.ISize(cbwm) - offsets.IEnd(cbwm) -
@@ -1917,13 +1910,9 @@ void ReflowInput::InitAbsoluteConstraints(const ReflowInput* aCBReflowInput,
                              borderPadding.IStartEnd(cbwm);
     }
   } else if (iEndIsAuto) {
-    // We know 'left' is not 'auto' anymore thanks to the hypothetical
-    // box code above.
-    // Solve for 'right'.
+    // We know 'inset-inline-start' is not 'auto' anymore thanks to the
+    // hypothetical box code above. Solve for 'inset-inline-end'.
     if (iSizeIsAuto) {
-      // XXXldb This, and the corresponding code in
-      // AbsoluteContainingBlock.cpp, could probably go away now that
-      // we always compute widths.
       offsets.IEnd(cbwm) = NS_AUTOOFFSET;
     } else {
       offsets.IEnd(cbwm) = aCBSize.ISize(cbwm) - offsets.IStart(cbwm) -
@@ -1958,7 +1947,7 @@ void ReflowInput::InitAbsoluteConstraints(const ReflowInput* aCBReflowInput,
       mStylePosition->BSize(cbwm, anchorResolutionParams.mBaseParams)
           ->BehavesLikeInitialValueOnBlockAxis();
   if (bStartIsAuto) {
-    // solve for block-start
+    // Solve for 'inset-block-start'.
     if (bSizeIsAuto) {
       offsets.BStart(cbwm) = NS_AUTOOFFSET;
     } else {
@@ -1967,7 +1956,7 @@ void ReflowInput::InitAbsoluteConstraints(const ReflowInput* aCBReflowInput,
                              computedSize.BSize(cbwm) - offsets.BEnd(cbwm);
     }
   } else if (bEndIsAuto) {
-    // solve for block-end
+    // Solve for 'inset-block-end'.
     if (bSizeIsAuto) {
       offsets.BEnd(cbwm) = NS_AUTOOFFSET;
     } else {