/// <summary>
///Commits current transaction. Optionally if <paramref name="withOmit"/> set to true erases transaction from undo history
/// </summary>
/// <param name="withOmit"></param>
/// <returns></returns>
public int Commit(bool withOmit)
{
this.ValidateModification();
int v = this.Version;
RuntimeHelpers.PrepareConstrainedRegions();
try {} finally {
if (withOmit)
{
ValueList <TransactionType> .Address address = this.version.ItemAddress(this.version.Count - 1);
Debug.Assert(address.Page[address.Index] == TransactionType.Edit, "Only edit transactions can be omitted");
address.Page[address.Index] = TransactionType.Omit;
}
this.CompletedVersion = v;
this.editorThread = null;
this.editor = null;
LockFreeSync.WriteBarrier();
}
EventHandler handler = this.Committed;
if (handler != null)
{
handler(this, EventArgs.Empty);
}
return(v);
}
/// <summary>
/// Shrinks list to new size.
/// It is guarantee that space allocated by PrepareAdd will not be freed here.
/// </summary>
/// <param name="newSize"></param>
public void Shrink(int newSize)
{
int oldSize = this.Count;
if (newSize < oldSize)
{
this.Count = newSize;
LockFreeSync.WriteBarrier();
for (int i = newSize >> LogPageSize; i < this.page.Length; i++)
{
TRow[] p = this.page[i];
if (p == null)
{
return;
}
for (int j = newSize & IndexOnPageMask; j < p.Length; j++)
{
if (oldSize <= newSize++)
{
return;
}
p[j] = default;
}
}
}
else if (oldSize < newSize)
{
throw new ArgumentOutOfRangeException(nameof(newSize));
}
}
/// <summary>
/// Gets record in the specified version
/// </summary>
/// <param name="rowId"></param>
/// <param name="version"></param>
/// <param name="data"></param>
public void GetData(RowId rowId, int version, out TRecord data)
{
if (version != 0)
{
this.ValidateVersion(version);
}
int pointIndex = this.snap.Count - 1;
ValueList <Snap> .Address snapAddress = this.snap.ItemAddress(pointIndex);
while (version < snapAddress.Page[snapAddress.Index].Version)
{
snapAddress = this.snap.ItemAddress(--pointIndex);
}
if (!(0 <= rowId.Value && rowId.Value < snapAddress.Page[snapAddress.Index].TableSize))
{
throw new ArgumentOutOfRangeException(nameof(rowId));
}
// cache log size here. the original can only grow in time
int logSize = snapAddress.Page[snapAddress.Index].LogSize;
ValueList <Row> .Address rowAddress = this.table.ItemAddress(rowId.Value);
if (rowAddress.Page[rowAddress.Index].LogIndex < logSize)
{
// so the latest version of data was requested.
data = rowAddress.Page[rowAddress.Index].Data;
bool isDeleted = rowAddress.Page[rowAddress.Index].IsDeleted;
LockFreeSync.ReadBarrier();
// check if the row is still of the latest version
if (rowAddress.Page[rowAddress.Index].LogIndex < logSize)
{
// if it is still latest return.
if (isDeleted)
{
data = default;
throw new ArgumentOutOfRangeException(nameof(rowId));
}
return;
}
}
// older version of the row requested. The data is in the log. Log is immutable so easy to read.
ValueList <Log> .Address logAddress = this.log.ItemAddress(rowAddress.Page[rowAddress.Index].LogIndex);
while (logSize <= logAddress.Page[logAddress.Index].LogIndex)
{
Debug.Assert(0 < logAddress.Page[logAddress.Index].LogIndex, "Log entry at 0 does not contain any real data and used as a stub");
logAddress = this.log.ItemAddress(logAddress.Page[logAddress.Index].LogIndex);
}
if (logAddress.Page[logAddress.Index].IsDeleted)
{
data = default;
throw new ArgumentOutOfRangeException(nameof(rowId));
}
data = logAddress.Page[logAddress.Index].Data;
}
/// <summary>
/// Adds new element assuming enough memory for it already exist. This method should be prepared by PrepareAdd call.
/// </summary>
/// <param name="row"></param>
/// <returns></returns>
public int FixedAdd(ref TRow row)
{
int index = this.Count;
//if(index == int.MaxValue) {
// throw new OverflowException();
//}
int pageIndex = index >> LogPageSize;
int itemIndex = index & IndexOnPageMask;
this.page[pageIndex][itemIndex] = row;
LockFreeSync.WriteBarrier();
this.Count++;
return(index);
}
/// <summary>
/// Reverts current transaction
/// </summary>
public void Rollback()
{
this.ValidateModification();
RuntimeHelpers.PrepareConstrainedRegions();
try { } finally {
foreach (ISnapTable snapTable in this.Tables)
{
snapTable.Rollback();
}
ValueList <TransactionType> .Address address = this.version.ItemAddress(this.version.Count - 1);
address.Page[address.Index] = TransactionType.Omit;
this.CompletedVersion = this.Version;
this.editorThread = null;
this.editor = null;
LockFreeSync.WriteBarrier();
}
}
/// <summary>
/// Ensures memory is allocated to accommodate for one more element
/// </summary>
public void PrepareAdd()
{
int index = this.Count;
if (int.MaxValue - 1 <= index)
{
throw new InvalidOperationException(Properties.Resources.ErrorValueListTooBig);
}
int pageIndex = index >> LogPageSize;
if (pageIndex == this.page.Length)
{
TRow[][] p = this.page;
Array.Resize <TRow[]>(ref p, p.Length * 2);
LockFreeSync.WriteBarrier();
this.page = p;
}
int itemIndex = index & IndexOnPageMask;
if (itemIndex == 0 && this.page[pageIndex] == null)
{
this.page[pageIndex] = new TRow[PageSize];
}
}
