public async Task <char[]> Fetch(PagePointerOffsetPair loc, ITransaction tran)
{
using Releaser lckReleaser = await tran.AcquireLock((ulong) loc.PageId, LockManager.LockTypeEnum.Shared).ConfigureAwait(false);
StringOnlyPage page = await allocator.GetPageStr((ulong)loc.PageId, tran).ConfigureAwait(false);
return(page.FetchWithOffset((uint)loc.OffsetInPage, tran));
}
public async Task <PagePointerOffsetPair> Add(char[] item, ITransaction tran)
{
StringOnlyPage currPage = null;
int offset;
for (ulong currPageId = this.lastPageId; currPageId != PageManagerConstants.NullPageId; currPageId = currPage.NextPageId())
{
using Releaser lckReleaser = await tran.AcquireLock(currPageId, LockManager.LockTypeEnum.Shared).ConfigureAwait(false);
currPage = await allocator.GetPageStr(currPageId, tran).ConfigureAwait(false);
if (currPage.CanFit(item))
{
lckReleaser.Dispose();
using Releaser writeLock = await tran.AcquireLock(currPageId, LockManager.LockTypeEnum.Exclusive).ConfigureAwait(false);
// Need to check can fit one more time.
if (currPage.CanFit(item))
{
offset = currPage.Insert(item, tran);
return(new PagePointerOffsetPair((long)currPage.PageId(), (int)offset));
}
}
}
{
using Releaser prevPage = await tran.AcquireLock(currPage.PageId(), LockManager.LockTypeEnum.Exclusive).ConfigureAwait(false);
if (currPage.NextPageId() != PageManagerConstants.NullPageId)
{
prevPage.Dispose();
return(await Add(item, tran).ConfigureAwait(false));
}
else
{
currPage = await this.allocator.AllocatePageStr(currPage.PageId(), PageManagerConstants.NullPageId, tran).ConfigureAwait(false);
using Releaser lckReleaser = await tran.AcquireLock(currPage.PageId(), LockManager.LockTypeEnum.Exclusive).ConfigureAwait(false);
offset = currPage.Insert(item, tran);
this.lastPageId = currPage.PageId();
return(new PagePointerOffsetPair((long)currPage.PageId(), (int)offset));
}
}
}
