IndexItem GetIndexItem(long index)
{
IndexItem indexItem;
var indexPage = _indexPageFactory.GetPage(GetIndexPageIndex(index));
using (var stream = indexPage.GetReadStream(GetIndexItemOffset(index), IndexItemSize))
{
indexItem = IndexItem.ReadFromStream(stream);
}
_indexPageFactory.ReleasePage(indexPage.Index);
return(indexItem);
}
private void PersistMetaData()
{
var metaPage = _metaPageFactory.GetPage(0);
using (var writeStream = metaPage.GetWriteStream(0, _metaDataItemSize))
{
_metaData.WriteToStream(writeStream);
}
_metaPageFactory.ReleasePage(0);
}
public void Enqueue(ReadOnlySpan <byte> itemData)
{
lock (_lockObject)
{
// Throw or silently return if itemData is null?
if (itemData == null)
{
return;
}
if (itemData.Length > _dataPageSize)
{
throw new ArgumentOutOfRangeException(nameof(itemData),
"Item data length is greater than queue data page size");
}
if (_tailDataItemOffset + itemData.Length > _dataPageSize) // Not enough space in current page
{
_tailDataPageIndex++;
_tailDataItemOffset = 0;
}
// Get data page
var dataPage = _dataPageFactory.GetPage(_tailDataPageIndex);
// Get write stream
using (var writeStream = dataPage.GetWriteStream(_tailDataItemOffset, itemData.Length))
{
// Write data to write stream
writeStream.Write(itemData);
}
// Release our reference to the data page
_dataPageFactory.ReleasePage(_tailDataPageIndex);
// Udate index
// Get index page
var indexPage = _indexPageFactory.GetPage(GetIndexPageIndex(_metaData.TailIndex));
// Get write stream
using (var writeStream =
indexPage.GetWriteStream(GetIndexItemOffset(_metaData.TailIndex), _indexItemSize))
{
var indexItem = new IndexItem
{
DataPageIndex = _tailDataPageIndex,
ItemOffset = _tailDataItemOffset,
ItemLength = itemData.Length
};
indexItem.WriteToStream(writeStream);
}
_indexPageFactory.ReleasePage(GetIndexPageIndex(_metaData.TailIndex));
// Advance
_tailDataItemOffset += itemData.Length;
// Update meta data
_metaData.TailIndex++;
_queueMonitor.Update(_metaData.TailIndex);
PersistMetaData();
}
}