NodeIterator-removal.html

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This WPT test may be referenced by the following Test IDs:
- /dom/traversal/NodeIterator-removal.html - WPT Dashboard Interop Dashboard

<!doctype html>

<title>NodeIterator removal tests</title>

<link rel="author" title="Aryeh Gregor" href=ayg@aryeh.name>

<meta name=timeout content=long>

<div id=log></div>

<script src=/resources/testharness.js></script>

<script src=/resources/testharnessreport.js></script>

<script src=../common.js></script>

<script>

"use strict";

for (var i = 0; i < testNodes.length; i++) {

  var node = eval(testNodes[i]);

  if (!node.parentNode) {

    // Nothing to test

    continue;

  test(function() {

    var iters = [];

    var descs = [];

    var expectedReferenceNodes = [];

    var expectedPointers = [];

    for (var j = 0; j < testNodes.length; j++) {

      var root = eval(testNodes[j]);

      // Add all distinct iterators with this root, calling nextNode()

      // repeatedly until it winds up with the same iterator.

      for (var k = 0; ; k++) {

        var iter = document.createNodeIterator(root);

        for (var l = 0; l < k; l++) {

          iter.nextNode();

        if (k && iter.referenceNode == iters[iters.length - 1].referenceNode

            && iter.pointerBeforeReferenceNode

               == iters[iters.length - 1].pointerBeforeReferenceNode) {

          break;

        } else {

          iters.push(iter);

          descs.push("document.createNodeIterator(" + testNodes[j]

            + ") advanced " + k + " times");

          expectedReferenceNodes.push(iter.referenceNode);

          expectedPointers.push(iter.pointerBeforeReferenceNode);

          var idx = iters.length - 1;

          // "If toBeRemovedNode is not an inclusive ancestor of nodeIterator's

          // reference, or toBeRemovedNode is an inclusive ancestor of

          // nodeIterator's root, then return."

          if (isInclusiveAncestor(node, root)

              || !isInclusiveAncestor(node, iter.referenceNode)) {

            continue;

          // "If the pointerBeforeReferenceNode attribute value is false, set

          // the referenceNode attribute to the first node preceding the node

          // that is being removed, and terminate these steps."

          if (!iter.pointerBeforeReferenceNode) {

            expectedReferenceNodes[idx] = previousNode(node);

            continue;

          // "If there is a node following the last inclusive descendant of the

          // node that is being removed, set the referenceNode attribute to the

          // first such node, and terminate these steps."

          var next = nextNodeDescendants(node);

          if (next) {

            expectedReferenceNodes[idx] = next;

            continue;

          // "Set the referenceNode attribute to the first node preceding the

          // node that is being removed and set the pointerBeforeReferenceNode

          // attribute to false."

          expectedReferenceNodes[idx] = previousNode(node);

          expectedPointers[idx] = false;

    var oldParent = node.parentNode;

    var oldSibling = node.nextSibling;

    oldParent.removeChild(node);

    for (var j = 0; j < iters.length; j++) {

      var iter = iters[j];

      assert_equals(iter.referenceNode, expectedReferenceNodes[j],

                    ".referenceNode of " + descs[j]);

      assert_equals(iter.pointerBeforeReferenceNode, expectedPointers[j],

                    ".pointerBeforeReferenceNode of " + descs[j]);

    oldParent.insertBefore(node, oldSibling);

  }, "Test removing node " + testNodes[i]);

testDiv.style.display = "none";

// Targeted coverage for the pre-remove step that fires when

// pointerBeforeReferenceNode is true and the iterator's reference is inside

// the subtree being removed. The parametric loop above only drives iterators

// forward with nextNode(), so pointerBeforeReferenceNode is true only when

// referenceNode === root — a case the algorithm's first step now always

// short-circuits. To reach the "find next within root" branch we have to back

// the iterator up with previousNode() first.

const buildScratchTree = (structure) => {

  // structure is a string like "root[a[a1],b[b1],c]"; returns an object whose

  // keys are the named elements.

  const nodes = {};

  let i = 0;

  const parse = (parent) => {

    let name = "";

    while (i < structure.length && /[A-Za-z0-9]/.test(structure[i])) {

      name += structure[i++];

    const el = document.createElement(name);

    nodes[name] = el;

    if (parent) parent.appendChild(el);

    if (structure[i] === "[") {

      i++;

      while (structure[i] !== "]") {

        parse(el);

        if (structure[i] === ",") i++;

      i++;

    return el;

};

  const root = parse(null);

  document.body.appendChild(root);

  return { root, nodes };

};

test((t) => {

  // Tree: root[a[a1], b[b1], c]

  const { root, nodes } = buildScratchTree("root[a[a1],b[b1],c]");

  t.add_cleanup(() => root.remove());

  const iter = document.createNodeIterator(root);

  for (let i = 0; i < 5; i++) iter.nextNode();

  assert_equals(iter.referenceNode, nodes.b1, "advanced reference");

  assert_false(iter.pointerBeforeReferenceNode, "advanced pointer");

  iter.previousNode();

  assert_equals(iter.referenceNode, nodes.b1, "backed-up reference");

  assert_true(iter.pointerBeforeReferenceNode, "backed-up pointer");

  nodes.b.remove();

  // pre-remove step 2: next-within-root exists, so reference jumps to it and

  // pointer stays true.

  assert_equals(iter.referenceNode, nodes.c, "post-removal reference");

  assert_true(iter.pointerBeforeReferenceNode, "post-removal pointer");

}, "Removing an inclusive ancestor of reference, pointer before reference is true, "

   + "with a following node within root");

test((t) => {

  // Tree: root[a[a1], b[b1]] — no node after b within root.

  const { root, nodes } = buildScratchTree("root[a[a1],b[b1]]");

  t.add_cleanup(() => root.remove());

  const iter = document.createNodeIterator(root);

  for (let i = 0; i < 5; i++) iter.nextNode();

  assert_equals(iter.referenceNode, nodes.b1, "advanced reference");

  assert_false(iter.pointerBeforeReferenceNode, "advanced pointer");

  iter.previousNode();

  assert_equals(iter.referenceNode, nodes.b1, "backed-up reference");

  assert_true(iter.pointerBeforeReferenceNode, "backed-up pointer");

  nodes.b.remove();

  // pre-remove step 2: no next-within-root, so pointer flips to false and

  // step 3 moves reference to the last inclusive descendant of b's previous

  // sibling.

  assert_equals(iter.referenceNode, nodes.a1, "post-removal reference");

  assert_false(iter.pointerBeforeReferenceNode, "post-removal pointer");

}, "Removing an inclusive ancestor of reference, pointer before reference is true, "

   + "with no following node within root");

</script>