Bug 1767256 - Include elements with display:contents when calculating range bounding rect r=emilio

Elements with display:contents does not participate in layout, but it's children does.  When
calculating the bounding rect of a range, those children have to be taken into account.

Differential Revision: https://phabricator.services.mozilla.com/D151229

dom/base/nsRange.cpp

@@ -27,11 +27,12 @@
 #include "mozilla/CheckedInt.h"
 #include "mozilla/ContentIterator.h"
 #include "mozilla/dom/CharacterData.h"
+#include "mozilla/dom/ChildIterator.h"
+#include "mozilla/dom/DOMRect.h"
+#include "mozilla/dom/DOMStringList.h"
 #include "mozilla/dom/DocumentFragment.h"
 #include "mozilla/dom/DocumentType.h"
 #include "mozilla/dom/RangeBinding.h"
-#include "mozilla/dom/DOMRect.h"
-#include "mozilla/dom/DOMStringList.h"
 #include "mozilla/dom/Selection.h"
 #include "mozilla/dom/Text.h"
 #include "mozilla/Maybe.h"
@@ -2695,6 +2696,50 @@ static nsresult GetPartialTextRect(RectCallback* aCallback,
   return NS_OK;
 }
 
+static void CollectClientRectsForSubtree(
+    nsINode* aNode, RectCallback* aCollector, Sequence<nsString>* aTextList,
+    nsINode* aStartContainer, uint32_t aStartOffset, nsINode* aEndContainer,
+    uint32_t aEndOffset, bool aClampToEdge, bool aFlushLayout) {
+  auto* content = nsIContent::FromNode(aNode);
+  if (!content) {
+    return;
+  }
+
+  if (content->IsText()) {
+    if (aNode == aStartContainer) {
+      int32_t offset = aStartContainer == aEndContainer
+                           ? static_cast<int32_t>(aEndOffset)
+                           : content->AsText()->TextDataLength();
+      GetPartialTextRect(aCollector, aTextList, content,
+                         static_cast<int32_t>(aStartOffset), offset,
+                         aClampToEdge, aFlushLayout);
+      return;
+    }
+
+    if (aNode == aEndContainer) {
+      GetPartialTextRect(aCollector, aTextList, content, 0,
+                         static_cast<int32_t>(aEndOffset), aClampToEdge,
+                         aFlushLayout);
+      return;
+    }
+  }
+
+  if (aNode->IsElement() && aNode->AsElement()->IsDisplayContents()) {
+    FlattenedChildIterator childIter(content);
+
+    for (nsIContent* child = childIter.GetNextChild(); child;
+         child = childIter.GetNextChild()) {
+      CollectClientRectsForSubtree(child, aCollector, aTextList,
+                                   aStartContainer, aStartOffset, aEndContainer,
+                                   aEndOffset, aClampToEdge, aFlushLayout);
+    }
+  } else if (nsIFrame* frame = content->GetPrimaryFrame()) {
+    nsLayoutUtils::GetAllInFlowRectsAndTexts(
+        frame, nsLayoutUtils::GetContainingBlockForClientRect(frame),
+        aCollector, aTextList, nsLayoutUtils::RECTS_ACCOUNT_FOR_TRANSFORMS);
+  }
+}
+
 /* static */
 void nsRange::CollectClientRectsAndText(
     RectCallback* aCollector, Sequence<nsString>* aTextList, nsRange* aRange,
@@ -2756,31 +2801,10 @@ void nsRange::CollectClientRectsAndText(
   do {
     nsCOMPtr<nsINode> node = iter.GetCurrentNode();
     iter.Next();
-    nsCOMPtr<nsIContent> content = do_QueryInterface(node);
-    if (!content) continue;
-    if (content->IsText()) {
-      if (node == startContainer) {
-        int32_t offset = startContainer == endContainer
-                             ? static_cast<int32_t>(aEndOffset)
-                             : content->AsText()->TextDataLength();
-        GetPartialTextRect(aCollector, aTextList, content,
-                           static_cast<int32_t>(aStartOffset), offset,
-                           aClampToEdge, aFlushLayout);
-        continue;
-      } else if (node == endContainer) {
-        GetPartialTextRect(aCollector, aTextList, content, 0,
-                           static_cast<int32_t>(aEndOffset), aClampToEdge,
-                           aFlushLayout);
-        continue;
-      }
-    }
 
-    nsIFrame* frame = content->GetPrimaryFrame();
-    if (frame) {
-      nsLayoutUtils::GetAllInFlowRectsAndTexts(
-          frame, nsLayoutUtils::GetContainingBlockForClientRect(frame),
-          aCollector, aTextList, nsLayoutUtils::RECTS_ACCOUNT_FOR_TRANSFORMS);
-    }
+    CollectClientRectsForSubtree(node, aCollector, aTextList, aStartContainer,
+                                 aStartOffset, aEndContainer, aEndOffset,
+                                 aClampToEdge, aFlushLayout);
   } while (!iter.IsDone());
 }
 

testing/web-platform/tests/css/cssom-view/range-bounding-client-rect-with-display-contents.html

@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Include display:contents elements recursively when calculating bounding rect for a ranges</title>
+<link rel="help" href="https://drafts.csswg.org/cssom-view-1/#dom-range-getboundingclientrect">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id="container">
+  <div id="spacerBefore">spacer before</div>
+  <div style="display:contents">
+    <div style="height:30px; background:lightblue">
+      HEIGHT: 30px
+    </div>
+    <div style="display:contents">
+      <div style="display:contents">
+        <div style="height:30px; background:lightblue">
+          HEIGHT: 30px
+        </div>
+      </div>
+    </div>
+  </div>
+  <div id="spacerAfter">spacer after</div>
+</div>
+<script>
+  test(function () {
+    const spacerBefore = document.getElementById("spacerBefore");
+    const spacerAfter = document.getElementById("spacerAfter");
+
+    const expected = spacerAfter.getBoundingClientRect().top - spacerBefore.getBoundingClientRect().bottom;
+
+    const rangeBetweenSpacers = document.createRange();
+    rangeBetweenSpacers.setStartAfter(spacerBefore);
+    rangeBetweenSpacers.setEndBefore(spacerAfter);
+
+    const actual = rangeBetweenSpacers.getBoundingClientRect().height;
+
+    assert_true(actual > 0, "range has vertical height");
+    assert_equals(expected, actual, "range.getBoundingClientRect().height");
+  }, "the space between elements using a range should be the same as using another method")
+</script>