2011-06-16  Julien Chaffraix  <jchaffraix@webkit.org>

        Reviewed by NOBODY (OOPS!).

        HTMLTable should cache its 'rows' collection results

        https://bugs.webkit.org/show_bug.cgi?id=62800

        * perf/table-rows-length-caching-expected.txt: Added.

        * perf/table-rows-length-caching.html: Added.

        This test checks that the call to table.rows is CONSTANT once it has

        been populated once (and the DOM is not mutated).

Tests that check that table.row.length is properly cached

PASS

<!DOCTYPE html>

<html>

<body>

<div id='sandbox'></div>

<div id="console"></div>

<script src="../resources/magnitude-perf.js"></script>

<script>

if (window.layoutTestController)

    layoutTestController.dumpAsText();

var table;

var sandbox = document.getElementById('sandbox');

// Check that table.rows.length is properly cached.

function setupTableRows(magnitude)

{

    if (sandbox.firstChild)

        sandbox.removeChild(sandbox.firstChild);

    table = document.createElement('table');

    for (var i = 0; i < magnitude; ++i) {

        var tr = document.createElement('tr');

        table.appendChild(tr);

    }

    sandbox.appendChild(table);

    // Make sure we have cached the length before testing!

    table.rows.length;

}

function testTableRows(magnitude)

{

    table.rows.length;

}

Magnitude.description('Tests that check that table.row.length is properly cached');

Magnitude.run(setupTableRows, testTableRows, Magnitude.CONSTANT);

sandbox.removeChild(sandbox.firstChild);

</script>

</body>

</html>

2011-06-16  Julien Chaffraix  <jchaffraix@webkit.org>

        Reviewed by NOBODY (OOPS!).

        HTMLTable should cache its 'rows' collection results

        https://bugs.webkit.org/show_bug.cgi?id=62800

        Test: perf/table-rows-length-caching.html

        Currently all our HTMLCollection's are recreated on call. This means that

        we don't cache the information about the collection between calls to, for

        example, table.rows.

        This change adds a CollectionCache to HTMLTableElement. It is similar to what

        is done for HTMLFormElement.

        * html/HTMLTableElement.cpp:

        (WebCore::HTMLTableElement::collectionCache): This method does

        lazy initialization of the table's collectionCache.

        * html/HTMLTableElement.h: Added a new member and the previous

        method.

        * html/HTMLTableRowsCollection.cpp:

        (WebCore::HTMLTableRowsCollection::HTMLTableRowsCollection): Pass

        the HTMLTableElement's CollectionCache so that we reuse the cached

        results.

CollectionCache* HTMLTableElement::collectionCache() const

{

    if (!m_collectionCache)

        m_collectionCache = adoptPtr(new CollectionCache());

    return m_collectionCache.get();

}

    CollectionCache* collectionCache() const;

    mutable OwnPtr<CollectionCache> m_collectionCache;