test_compute_data_with_start_struct.html

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  <title>Test for correct handling of aStartStruct parameter to nsRuleNode::Compute*Data</title>

  <script src="/tests/SimpleTest/SimpleTest.js"></script>

  <script type="text/javascript" src="property_database.js"></script>

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<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=216456">Mozilla Bug 216456</a>

<p id="display">

  <span id="base"></span>

  <span id="test"></span>

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<pre id="test">

<script class="testbody" type="text/javascript">

/**

 * The purpose of this test was to test that in the old style system

 * the nsRuleNode::Compute*Data functions were written correctly.

 * In particular, in these functions, when the specified value of a

 * property had unit eCSSUnit_Null, touching the computed data is

 * forbidden. This is because we sometimes would stop walking up the

 * rule tree when we find computed data for an initial subsequence of

 * our rules (i.e., an ancestor rule node) that we can use as a starting

 * point (aStartStruct) for the computation for the current rule node.

 * However, we don't cache style structs in the rule tree in the current

 * style system code, and property cascading no longer relies on hand

 * written functions, so this particular failure mode isn't as likely to

 * happen.

*/

var gStyleSheet = document.getElementById("stylesheet").sheet;

var gRule1 = gStyleSheet.cssRules[gStyleSheet.insertRule("#base, #test {}", gStyleSheet.cssRules.length)];

var gRule2 = gStyleSheet.cssRules[gStyleSheet.insertRule("#test {}", gStyleSheet.cssRules.length)];

var gBase = getComputedStyle(document.getElementById("base"), "");

var gTest = getComputedStyle(document.getElementById("test"), "");

function test_property(prop, lower_set, higher_set) {

  var info = gCSSProperties[prop];

  if (info.subproperties || info.logical)

    return;

  gRule1.style.setProperty(prop, info[lower_set][0]);

  gRule2.style.setProperty(prop, info[higher_set][0]);

  if ("prerequisites" in info) {

    for (var prereq in info.prerequisites) {

      gRule2.style.setProperty(prereq, info.prerequisites[prereq], "");

  gBase.getPropertyValue(prop);

  var higher_set_val = gTest.getPropertyValue(prop);

  gRule2.style.setProperty(prop, info[lower_set][0], "");

  var lower_set_val = gTest.getPropertyValue(prop);

  isnot(higher_set_val, lower_set_val, "initial and other values of " + prop + " are different");

  gRule2.style.removeProperty(prop);

  is(gTest.getPropertyValue(prop), lower_set_val, prop + " is not touched when its value comes from aStartStruct");

  gRule1.style.removeProperty(prop);

  if ("prerequisites" in info) {

    for (var prereq in info.prerequisites) {

      gRule2.style.removeProperty(prereq);

function round(lower_set, higher_set) {

  for (var prop in gCSSProperties)

    test_property(prop, lower_set, higher_set);

round("other_values", "initial_values");

round("initial_values", "other_values");

</script>

</pre>

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