static RC walIndexPage(Wal wal, Pid id, ref object idOut)
{
// Enlarge the pWal->apWiData[] array if required
if (wal.WiData.Length <= id)
{
var bytes = (int)(1 * (id + 1));
var newWiData = SysEx.Realloc <object>(1, wal.WiData, bytes);
if (newWiData != null)
{
idOut = null;
return(RC.NOMEM);
}
Array.Clear(newWiData, wal.WiData.Length, (int)(id + 1 - wal.WiData.Length));
wal.WiData = newWiData;
}
// Request a pointer to the required page from the VFS
var rc = RC.OK;
if (wal.WiData[id] == null)
{
if (wal.ExclusiveMode_ == Wal.MODE.HEAPMEMORY)
{
wal.WiData[id] = C._alloc <Pid>(4, WALINDEX_PGSZ, true);
if (wal.WiData[id] != null)
{
rc = RC.NOMEM;
}
}
else
{
rc = wal.DBFile.ShmMap((int)id, WALINDEX_PGSZ, (int)wal.WriteLock, wal.WiData, (int)id);
if (rc == RC.READONLY)
{
wal.ReadOnly_ |= READONLY.SHM_RDONLY;
rc = RC.OK;
}
}
}
idOut = wal.WiData[id];
Debug.Assert(id == 0 || idOut != null || rc != RC.OK);
return(rc);
}