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shannonbooth merged 1 commit into from
Apr 17, 2026
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LibWeb/DOM: Collapse ranges before DOM mutations #8944

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137 changes: 77 additions & 60 deletions Libraries/LibWeb/DOM/Range.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -603,45 +603,46 @@ WebIDL::ExceptionOr<GC::Ref<DocumentFragment>> Range::extract()
if (collapsed())
return fragment;

// 3. Let original start node, original start offset, original end node, and original end offset
// be range’s start node, start offset, end node, and end offset, respectively.
// 3. Let originalStartNode, originalStartOffset, originalEndNode, and originalEndOffset be range’s start node,
// start offset, end node, and end offset, respectively.
GC::Ref<Node> original_start_node = m_start_container;
auto original_start_offset = m_start_offset;
GC::Ref<Node> original_end_node = m_end_container;
auto original_end_offset = m_end_offset;

// 4. If original start node is original end node and it is a CharacterData node, then:
// 4. If originalStartNode is originalEndNode and it is a CharacterData node:
if (original_start_node.ptr() == original_end_node.ptr() && is<CharacterData>(*original_start_node)) {
// 1. Let clone be a clone of original start node.
// 1. Let clone be a clone of originalStartNode.
auto clone = TRY(original_start_node->clone_node());

// 2. Set the data of clone to the result of substringing data with node original start node,
// offset original start offset, and count original end offset minus original start offset.
// 2. Set clone’s data to the result of substringing data of originalStartNode with originalStartOffset and
// originalEndOffset − originalStartOffset.
auto result = TRY(static_cast<CharacterData const&>(*original_start_node).substring_data(original_start_offset, original_end_offset - original_start_offset));
as<CharacterData>(*clone).set_data(move(result));

// 3. Append clone to fragment.
TRY(fragment->append_child(clone));

// 4. Replace data with node original start node, offset original start offset, count original end offset minus original start offset, and data the empty string.
// 4. Replace data of originalStartNode with originalStartOffset, originalEndOffset − originalStartOffset, and
// the empty string.
TRY(static_cast<CharacterData&>(*original_start_node).replace_data(original_start_offset, original_end_offset - original_start_offset, {}));

// 5. Return fragment.
return fragment;
}

// 5. Let common ancestor be original start node.
// 5. Let commonAncestor be originalStartNode.
GC::Ref<Node> common_ancestor = original_start_node;

// 6. While common ancestor is not an inclusive ancestor of original end node, set common ancestor to its own parent.
// 6. While commonAncestor is not an inclusive ancestor of originalEndNode: set commonAncestor to its own parent.
while (!common_ancestor->is_inclusive_ancestor_of(original_end_node))
common_ancestor = *common_ancestor->parent_node();

// 7. Let first partially contained child be null.
// 7. Let firstPartiallyContainedChild be null.
GC::Ptr<Node> first_partially_contained_child;

// 8. If original start node is not an inclusive ancestor of original end node,
// set first partially contained child to the first child of common ancestor that is partially contained in range.
// 8. If originalStartNode is not an inclusive ancestor of originalEndNode, then set firstPartiallyContainedChild
// to the first child of commonAncestor that is partially contained in range.
if (!original_start_node->is_inclusive_ancestor_of(original_end_node)) {
for (auto* child = common_ancestor->first_child(); child; child = child->next_sibling()) {
if (partially_contains_node(*child)) {
Expand All @@ -651,11 +652,11 @@ WebIDL::ExceptionOr<GC::Ref<DocumentFragment>> Range::extract()
}
}

// 9. Let last partially contained child be null.
// 9. Let lastPartiallyContainedChild be null.
GC::Ptr<Node> last_partially_contained_child;

// 10. If original end node is not an inclusive ancestor of original start node,
// set last partially contained child to the last child of common ancestor that is partially contained in range.
// 10. If originalEndNode is not an inclusive ancestor of originalStartNode, then set lastPartiallyContainedChild
// to the last child of commonAncestor that is partially contained in range.
if (!original_end_node->is_inclusive_ancestor_of(original_start_node)) {
for (auto* child = common_ancestor->last_child(); child; child = child->previous_sibling()) {
if (partially_contains_node(*child)) {
Expand All @@ -665,66 +666,75 @@ WebIDL::ExceptionOr<GC::Ref<DocumentFragment>> Range::extract()
}
}

// 11. Let contained children be a list of all children of common ancestor that are contained in range, in tree order.
// 11. Let containedChildren be a list of all children of commonAncestor that are contained in range, in tree order.
Vector<GC::Ref<Node>> contained_children;
for (Node* node = common_ancestor->first_child(); node; node = node->next_sibling()) {
if (contains_node(*node))
contained_children.append(*node);
}

// 12. If any member of contained children is a doctype, then throw a "HierarchyRequestError" DOMException.
// 12. If any member of containedChildren is a doctype, then throw a "HierarchyRequestError" DOMException.
for (auto const& child : contained_children) {
if (is<DocumentType>(*child))
return WebIDL::HierarchyRequestError::create(realm(), "Contained child is a DocumentType"_utf16);
}

// 13. Let newNode and newOffset be null.
GC::Ptr<Node> new_node;
size_t new_offset = 0;

// 13. If original start node is an inclusive ancestor of original end node, set new node to original start node and new offset to original start offset.
// 14. If originalStartNode is an inclusive ancestor of originalEndNode, then set newNode to originalStartNode and
// newOffset to originalStartOffset.
if (original_start_node->is_inclusive_ancestor_of(original_end_node)) {
new_node = original_start_node;
new_offset = original_start_offset;
}
// 14. Otherwise:
// 15. Otherwise:
else {
// 1. Let reference node equal original start node.
// 1. Let referenceNode be originalStartNode.
GC::Ptr<Node> reference_node = original_start_node;

// 2. While reference node’s parent is not null and is not an inclusive ancestor of original end node, set reference node to its parent.
// 2. While referenceNode’s parent is non-null and is not an inclusive ancestor of originalEndNode:
// set referenceNode to its parent.
while (reference_node->parent_node() && !reference_node->parent_node()->is_inclusive_ancestor_of(original_end_node))
reference_node = reference_node->parent_node();

// 3. Set new node to the parent of reference node, and new offset to one plus reference node’s index.
// 3. Set newNode to the parent of referenceNode, and newOffset to referenceNode’s index + 1.
new_node = reference_node->parent_node();
new_offset = 1 + reference_node->index();
new_offset = reference_node->index() + 1;
}

// 15. If first partially contained child is a CharacterData node, then:
// 16. Set range’s start and end to (newNode, newOffset).
TRY(set_start(*new_node, new_offset));
TRY(set_end(*new_node, new_offset));

// 17. If firstPartiallyContainedChild is a CharacterData node:
if (first_partially_contained_child && is<CharacterData>(*first_partially_contained_child)) {
// 1. Let clone be a clone of original start node.
// 1. Let clone be a clone of originalStartNode.
auto clone = TRY(original_start_node->clone_node());

// 2. Set the data of clone to the result of substringing data with node original start node, offset original start offset,
// and count original start node’s length minus original start offset.
// 2. Set the data of clone to the result of substringing data of originalStartNode with originalStartOffset
// and originalStartNode’s length − originalStartOffset.
auto result = TRY(static_cast<CharacterData const&>(*original_start_node).substring_data(original_start_offset, original_start_node->length() - original_start_offset));
as<CharacterData>(*clone).set_data(move(result));

// 3. Append clone to fragment.
TRY(fragment->append_child(clone));

// 4. Replace data with node original start node, offset original start offset, count original start node’s length minus original start offset, and data the empty string.
// 4. Replace data of originalStartNode with originalStartOffset, originalStartNode’s length −
// originalStartOffset, and the empty string.
TRY(static_cast<CharacterData&>(*original_start_node).replace_data(original_start_offset, original_start_node->length() - original_start_offset, {}));
}
// 16. Otherwise, if first partially contained child is not null:
// 18. Otherwise, if firstPartiallyContainedChild is non-null:
else if (first_partially_contained_child) {
// 1. Let clone be a clone of first partially contained child.
// 1. Let clone be a clone of firstPartiallyContainedChild.
auto clone = TRY(first_partially_contained_child->clone_node());

// 2. Append clone to fragment.
TRY(fragment->append_child(clone));

// 3. Let subrange be a new live range whose start is (original start node, original start offset) and whose end is (first partially contained child, first partially contained child’s length).
// 3. Let subrange be a new live range whose start is (originalStartNode, originalStartOffset) and whose end is
// (firstPartiallyContainedChild, firstPartiallyContainedChild’s length).
auto subrange = Range::create(original_start_node, original_start_offset, *first_partially_contained_child, first_partially_contained_child->length());

// 4. Let subfragment be the result of extracting subrange.
Expand All @@ -734,35 +744,36 @@ WebIDL::ExceptionOr<GC::Ref<DocumentFragment>> Range::extract()
TRY(clone->append_child(subfragment));
}

// 17. For each contained child in contained children, append contained child to fragment.
// 19. For each contained child of containedChildren: append contained child to fragment.
for (auto& contained_child : contained_children) {
TRY(fragment->append_child(contained_child));
}

// 18. If last partially contained child is a CharacterData node, then:
// 20. If lastPartiallyContainedChild is a CharacterData node:
if (last_partially_contained_child && is<CharacterData>(*last_partially_contained_child)) {
// 1. Let clone be a clone of original end node.
// 1. Let clone be a clone of originalEndNode.
auto clone = TRY(original_end_node->clone_node());

// 2. Set the data of clone to the result of substringing data with node original end node, offset 0, and count original end offset.
// 2. Set clone’s data to the result of substringing data of originalEndNode with 0 and originalEndOffset.
auto result = TRY(static_cast<CharacterData const&>(*original_end_node).substring_data(0, original_end_offset));
as<CharacterData>(*clone).set_data(move(result));

// 3. Append clone to fragment.
TRY(fragment->append_child(clone));

// 4. Replace data with node original end node, offset 0, count original end offset, and data the empty string.
// 4. Replace data of originalEndNode with 0, originalEndOffset, and the empty string.
TRY(as<CharacterData>(*original_end_node).replace_data(0, original_end_offset, {}));
}
// 19. Otherwise, if last partially contained child is not null:
// 21. Otherwise, if lastPartiallyContainedChild is non-null:
else if (last_partially_contained_child) {
// 1. Let clone be a clone of last partially contained child.
// 1. Let clone be a clone of lastPartiallyContainedChild.
auto clone = TRY(last_partially_contained_child->clone_node());

// 2. Append clone to fragment.
TRY(fragment->append_child(clone));

// 3. Let subrange be a new live range whose start is (last partially contained child, 0) and whose end is (original end node, original end offset).
// 3. Let subrange be a new live range whose start is (lastPartiallyContainedChild, 0) and whose end is
// (originalEndNode, originalEndOffset).
auto subrange = Range::create(*last_partially_contained_child, 0, original_end_node, original_end_offset);

// 4. Let subfragment be the result of extracting subrange.
Expand All @@ -772,11 +783,7 @@ WebIDL::ExceptionOr<GC::Ref<DocumentFragment>> Range::extract()
TRY(clone->append_child(subfragment));
}

// 20. Set range’s start and end to (new node, new offset).
TRY(set_start(*new_node, new_offset));
TRY(set_end(*new_node, new_offset));

// 21. Return fragment.
// 22. Return fragment.
return fragment;
}

Expand Down Expand Up @@ -1082,63 +1089,73 @@ WebIDL::ExceptionOr<void> Range::delete_contents()
if (collapsed())
return {};

// 2. Let original start node, original start offset, original end node, and original end offset be this’s start node, start offset, end node, and end offset, respectively.
// 2. Let originalStartNode, originalStartOffset, originalEndNode, and originalEndOffset be this’s start node,
// start offset, end node, and end offset, respectively.
GC::Ref<Node> original_start_node = m_start_container;
auto original_start_offset = m_start_offset;
GC::Ref<Node> original_end_node = m_end_container;
auto original_end_offset = m_end_offset;

// 3. If original start node is original end node and it is a CharacterData node, then replace data with node original start node, offset original start offset,
// count original end offset minus original start offset, and data the empty string, and then return.
// 3. If originalStartNode is originalEndNode and it is a CharacterData node:
if (original_start_node.ptr() == original_end_node.ptr() && is<CharacterData>(*original_start_node)) {
// 1. Replace data of originalStartNode with originalStartOffset, originalEndOffset − originalStartOffset, and
// the empty string.
TRY(static_cast<CharacterData&>(*original_start_node).replace_data(original_start_offset, original_end_offset - original_start_offset, {}));
// 2. Return.
return {};
}

// 4. Let nodes to remove be a list of all the nodes that are contained in this, in tree order, omitting any node whose parent is also contained in this.
// 4. Let nodesToRemove be a list of all the nodes that are contained in this, in tree order, omitting any node
// whose parent is also contained in this.
GC::RootVector<Node*> nodes_to_remove(heap());
for (GC::Ptr<Node> node = start_container(); node != end_container()->next_sibling(); node = node->next_in_pre_order()) {
if (contains_node(*node) && (!node->parent_node() || !contains_node(*node->parent_node())))
nodes_to_remove.append(node);
}

// 5. Let newNode and newOffset be null.
GC::Ptr<Node> new_node;
size_t new_offset = 0;

// 5. If original start node is an inclusive ancestor of original end node, set new node to original start node and new offset to original start offset.
// 6. If originalStartNode is an inclusive ancestor of originalEndNode, then set newNode to originalStartNode and
// newOffset to originalStartOffset.
if (original_start_node->is_inclusive_ancestor_of(original_end_node)) {
new_node = original_start_node;
new_offset = original_start_offset;
}
// 6. Otherwise
// 7. Otherwise
else {
// 1. Let reference node equal original start node.
// 1. Let referenceNode be originalStartNode.
auto reference_node = original_start_node;

// 2. While reference node’s parent is not null and is not an inclusive ancestor of original end node, set reference node to its parent.
// 2. While referenceNode’s parent is non-null and is not an inclusive ancestor of originalEndNode:
// set referenceNode to its parent.
while (reference_node->parent_node() && !reference_node->parent_node()->is_inclusive_ancestor_of(original_end_node))
reference_node = *reference_node->parent_node();

// 3. Set new node to the parent of reference node, and new offset to one plus the index of reference node.
// 3. Set newNode to referenceNode’s parent and newOffset to referenceNode’s index + 1.
new_node = reference_node->parent_node();
new_offset = 1 + reference_node->index();
new_offset = reference_node->index() + 1;
}

// 7. If original start node is a CharacterData node, then replace data with node original start node, offset original start offset, count original start node’s length minus original start offset, data the empty string.
// 8. Set this’s start and end to (newNode, newOffset).
TRY(set_start(*new_node, new_offset));
TRY(set_end(*new_node, new_offset));

// 9. If originalStartNode is a CharacterData node, then replace data of originalStartNode with
// originalStartOffset, originalStartNode’s length − originalStartOffset, and the empty string.
if (is<CharacterData>(*original_start_node))
TRY(static_cast<CharacterData&>(*original_start_node).replace_data(original_start_offset, original_start_node->length() - original_start_offset, {}));

// 8. For each node in nodes to remove, in tree order, remove node.
// 10. For each node of nodesToRemove, in tree order: remove node.
for (auto& node : nodes_to_remove)
node->remove();

// 9. If original end node is a CharacterData node, then replace data with node original end node, offset 0, count original end offset and data the empty string.
// 11. If originalEndNode is a CharacterData node, then replace data of originalEndNode with 0, originalEndOffset,
// and the empty string.
if (is<CharacterData>(*original_end_node))
TRY(static_cast<CharacterData&>(*original_end_node).replace_data(0, original_end_offset, {}));

// 10. Set start and end to (new node, new offset).
TRY(set_start(*new_node, new_offset));
TRY(set_end(*new_node, new_offset));
return {};
}

Expand Down
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