<!DOCTYPE html>
<html>
<body>
<script src="../../resources/runner.js"></script>
<script>

const numberOfIterations = 20;
const numberOfItems = 5000;
const cursorStep = 2;

// Delete database(s) for the test ahead of time.
var databaseName = "index-cursor-advance-DB";
indexedDB.deleteDatabase(databaseName).onsuccess = function() {
    startIteration();
}

var testGenerator = null;
var db = null;

PerfTestRunner.prepareToMeasureValuesAsync({
    customIterationCount: numberOfIterations,
    unit: 'ms',
    done: function () {
        db = null;
        testGenerator = null;
        PerfTestRunner.gc();
    }
});

function startIteration()
{
    testGenerator = runIteration();
    nextStep();
}

function nextStep()
{
    testGenerator.next();
}

function *runIteration()
{
    var openRequest = indexedDB.open(databaseName);
    openRequest.onupgradeneeded = function(event) {
        db = event.target.result;
        var objectStore = db.createObjectStore('store');
        objectStore.createIndex('index', 'indexKey');
        for (var i = 0; i < numberOfItems; ++i)
           objectStore.put({ value: 'value', indexKey: "index" + i }, i);
    }
    openRequest.onsuccess = nextStep;

    yield;

    var startTime = PerfTestRunner.now();

    var index = db.transaction('store').objectStore('store').index('index');
    var position = 0;
    index.openCursor().onsuccess = function(event) {
        var cursor = event.target.result;
        if(cursor) {
            cursor.advance(cursorStep);
            position += cursorStep;
        } else {
            if (position < numberOfItems) 
                alert("Expected cursor to stop after position" + numberOfItems + ", but stopped at " + position);

            nextStep();
        }
    }

    yield;

    if (!PerfTestRunner.measureValueAsync(PerfTestRunner.now() - startTime))
        return;

    setTimeout(startIteration, 0);
}
</script>
</body>
</html>