public void WillCheckPreviousPage()
{
var scheduler = new TestScheduler();
using (var file = new TestFile())
{
file.Append(Enumerable.Range(1, 20).Select(i => i.ToString()).ToArray());
ILineProvider lineProvider = null;
using (file.Info.Index(scheduler).Exclude(str => str.Contains("9")).Subscribe(x => lineProvider = x))
{
scheduler.AdvanceByMilliSeconds(250);
lineProvider.Count.Should().Be(20);
var lines = lineProvider.ReadLines(new ScrollRequest(10)).AsArray();
lines.Count().Should().Be(9);
var expected = Enumerable.Range(1, 20)
.Select(i => i.ToString())
.Where(str => !str.Contains("9"))
.Reverse()
.Take(10);
//slines.Select(line => line.Text).Should().BeEquivalentTo(expected);
}
}
}
public IEnumerable <Line> ReadLinesImpl(ScrollRequest scroll)
{
var currentPage = _lines.ReadLines(scroll).Where(line => !_itemsToExclude(line.Text)).ToArray();
foreach (var line in currentPage)
{
yield return(line);
}
if (currentPage.Length == scroll.PageSize)
{
yield break;
}
var deficit = scroll.PageSize - currentPage.Length;
//work backwards through the file until we have enough lines
var traverseUpTail = YieldTail(scroll.PageSize, scroll.FirstIndex - scroll.PageSize, deficit);
foreach (var line in traverseUpTail)
{
yield return(line);
}
}
