/// <summary>
/// Reads the current value of <see cref="Cursor"/>.
/// </summary>
/// <param name="itemValue">A <see cref="ResourcePoolItem{MemoryStream}"/> that provides
/// streams used for deserializing the value.</param>
/// <param name="valueBuffer">Outputs the <see cref="DataBuffer"/> value read.</param>
/// <returns>The <see cref="Int32"/> length of the cursor read.</returns>
public int ReadCursor(ResourcePoolItem <MemoryStream> itemValue, out DataBuffer valueBuffer)
{
var valueStream = itemValue.Item;
valueBuffer = SerializingObjectStorage.GetReadBuffer(valueStream);
var results = Cursor.Get(valueBuffer, true);
if (results < 0)
{
return(results);
}
var bfExcessValue = SerializingObjectStorage.GetExcessBuffer(valueStream, valueBuffer, results);
if (!bfExcessValue.IsEmpty)
{
var len = valueBuffer.Length;
valueBuffer = bfExcessValue;
if (!Storage.Storage.SupportsIncompleteReads)
{
bfExcessValue = bfExcessValue.RestrictOffset(len);
results = Cursor.Get(len, bfExcessValue, false);
if (results >= 0)
{
results += len;
}
}
else
{
results = Cursor.Get(0, bfExcessValue, false);
}
}
return(results);
}
/// <summary>
/// <para>Initializes a new instance of the <see cref="ObjectListForSingles{T, THeader}"/> class
/// for an existing list.</para>
/// </summary>
/// <param name="storage">
/// <para>The <see cref="SerializingObjectStorage"/> containing the list.</para>
/// </param>
/// <param name="keySpace">
/// <para>The <see cref="DataBuffer"/> keyspace the list is stored in.</para>
/// </param>
/// <param name="key">
/// <para>The single <see cref="StorageKey"/> all the binary entries are
/// stored under.</para>
/// </param>
/// <param name="buffer">
/// <para><see cref="DataBuffer"/> that holds the entire list. If
/// <see cref="DataBuffer.IsEmpty"/> is true, then the list is read
/// from <paramref name="storage"/>.</para>
/// </param>
/// <param name="creator">
/// <para>The <see cref="Func{T}"/> that produces new <typeparamref name="T"/>
/// instances for deserialization.</para>
/// </param>
/// <param name="headerCreator">
/// <para>The <see cref="Func{THeader}"/> that produces new <typeparamref name="THeader"/>
/// instances for deserialization.</para>
/// </param>
public ObjectListForSingles(SerializingObjectStorage storage, DataBuffer keySpace,
StorageKey key, DataBuffer buffer, Func <T> creator, Func <THeader> headerCreator)
: this(storage, keySpace, key, creator)
{
ArraySegment <byte> seg;
if (buffer.IsEmpty)
{
_stream = _pooled.Item;
buffer = SerializingObjectStorage.GetReadBuffer(_stream);
var entryLen = storage.Storage.Get(keySpace, key, buffer);
if (entryLen < 0)
{
throw new ApplicationException(string.Format(
"No list found for key space '{0}', key '{1}'",
keySpace, key));
}
var bfExcess = SerializingObjectStorage.GetExcessBuffer(_stream, buffer,
entryLen);
if (bfExcess.IsEmpty)
{
buffer = buffer.Restrict(entryLen);
}
else
{
if (storage.Storage.SupportsIncompleteReads)
{
storage.Storage.Get(keySpace, key, buffer.Length,
bfExcess.RestrictOffset(buffer.Length));
}
else
{
storage.Storage.Get(keySpace, key, 0, bfExcess);
}
buffer = bfExcess;
}
seg = buffer.ByteArraySegmentValue;
}
else
{
_pooled.Dispose();
_pooled = null;
seg = buffer.ByteArraySegmentValue;
_stream = new MemoryStream(seg.Array, seg.Offset, seg.Count);
}
var ticks = BitConverter.ToInt64(seg.Array, seg.Offset);
// expires listed first, since SetExpires can change it by itself
// and this way it doesn't have to worry about future changes
// to header
Expires = new DateTime(ticks);
_stream.Position = sizeof(long);
_header = headerCreator();
Serializer.Deserialize(_stream, _header);
_headerLength = _stream.Position;
}
