public void SaveAttachment(Stream s, Attachment a)
{
using (FileStream fs = ndb.GetReadStream())
{
BTree <Node> subNodeTreeMessage = a.subNodeTreeProperties;
if (subNodeTreeMessage == null)
{
// No subNodeTree given: assume we can look it up in the main tree
ndb.LookupNodeAndReadItsSubNodeBtree(fs, a.Parent.Nid, out subNodeTreeMessage);
}
var subNodeTreeAttachment = ltp.ReadProperties <Attachment>(fs, subNodeTreeMessage, a.Nid, pgAttachmentContent, a);
// If the value is inline, we just write it out
if (a.Content.GetType() == typeof(byte[]))
{
s.Write(a.Content, 0, a.Content.Length);
}
// Otherwise we need to dereference the node pointing to the data,
// using the subnode tree belonging to the attachment
else if (a.Content.GetType() == typeof(NID))
{
var nb = NDB.LookupSubNode(subNodeTreeAttachment, (NID)a.Content);
// Copy the data to the output file stream without getting it all into memory at once,
// as there can be a lot of data
ndb.CopyDataBlocks(fs, s, nb.DataBid);
}
}
}
// Read all of the data blocks for a table, in the case where the rows are to be accessed via a sub node
// The variation here is that for reading rows, we need to retain the block structure, so we return a set of blocks
private List <RowDataBlock> ReadSubNodeRowDataBlocks(FileStream fs, BTree <Node> subNodeTree, NID nid)
{
var blocks = new List <RowDataBlock>();
var n = NDB.LookupSubNode(subNodeTree, nid);
if (n == null)
{
throw new XstException("Sub node NID not found");
}
if (n.SubDataBid != 0)
{
throw new XstException("Sub-nodes of sub-nodes not yet implemented");
}
foreach (var buf in ndb.ReadDataBlocks(fs, n.DataBid))
{
blocks.Add(new RowDataBlock
{
Buffer = buf,
Offset = 0,
Length = buf.Length,
});
}
return(blocks);
}
public XstFile(View view, string fullName)
{
this.ndb = new NDB(fullName);
this.ltp = new LTP(ndb);
this.view = view;
}
public LTP(NDB ndb)
{
this.ndb = ndb;
}
// Test for the presence of an optional table in the supplied sub node tree
public bool IsTablePresent(BTree <Node> subNodeTree, NID nid)
{
return(subNodeTree != null && NDB.LookupSubNode(subNodeTree, nid) != null);
}
public XstFile(string fullName)
{
this.ndb = new NDB(fullName);
this.ltp = new LTP(ndb);
}
