/// <summary>
/// Gets the dataview corresponding to this sub-IDV entry. This will
/// lazily load the file, if it has not previously been requested. This
/// will return <c>null</c> if the offset is 0.
/// </summary>
public IDataView GetViewOrNull()
{
if (_view == null && _offset > 0)
{
Stream stream = _parent._file.Open(0);
stream.Seek(_offset, SeekOrigin.Begin);
Contracts.Check(stream.Position == _offset, "Unexpected position on substream");
SubsetStream ss = new SubsetStream(stream, _length);
var binArgs = new BinaryLoader.Arguments();
if (_parent._threads > 0)
{
binArgs.Threads = _parent._threads;
}
BinaryLoader loader = new BinaryLoader(Host,
binArgs, ss, leaveOpen: false);
var view = Interlocked.CompareExchange(ref _view, loader, null);
// If multiple threads have called this as it was being loaded,
// have ensure that this check only happens once.
if (view == loader)
{
VerifyView(view);
}
}
return(_view);
}
static IDataTransform Create(IHostEnvironment env, Arguments args, IDataView input, out IDataView sourceCtx)
{
sourceCtx = input;
env.CheckValue(args.tag, "Tag cannot be empty.");
if (TagHelper.EnumerateTaggedView(true, input).Where(c => c.Item1 == args.tag).Any())
{
throw env.Except("Tag '{0}' is already used.", args.tag);
}
env.CheckValue(args.selectTag, "Selected tag cannot be empty.");
if (string.IsNullOrEmpty(args.filename))
{
var selected = TagHelper.EnumerateTaggedView(true, input).Where(c => c.Item1 == args.selectTag);
if (!selected.Any())
{
throw env.Except("Unable to find a view to select with tag '{0}'. Did you forget to specify a filename?", args.selectTag);
}
var first = selected.First();
if (selected.Skip(1).Any())
{
throw env.Except("Tag '{0}' is ambiguous, {1} views were found.", args.selectTag, selected.Count());
}
var tagged = input as ITaggedDataView;
if (tagged == null)
{
var ag = new TagViewTransform.Arguments {
tag = args.tag
};
tagged = new TagViewTransform(env, ag, input);
}
first.Item2.AddRange(new[] { new Tuple <string, ITaggedDataView>(args.tag, tagged) });
tagged.AddRange(new[] { new Tuple <string, ITaggedDataView>(args.selectTag, first.Item2) });
#if (DEBUG_TIP)
long count = DataViewUtils.ComputeRowCount(tagged);
if (count == 0)
{
throw env.Except("Replaced view is empty.");
}
count = DataViewUtils.ComputeRowCount(first.Item2);
if (count == 0)
{
throw env.Except("Selected view is empty.");
}
#endif
var tr = first.Item2 as IDataTransform;
env.AssertValue(tr);
return(tr);
}
else
{
if (!File.Exists(args.filename))
{
throw env.Except("Unable to find file '{0}'.", args.filename);
}
var selected = TagHelper.EnumerateTaggedView(true, input).Where(c => c.Item1 == args.selectTag);
if (selected.Any())
{
throw env.Except("Tag '{0}' was already given. It cannot be assigned to the new file.", args.selectTag);
}
var loaderArgs = new BinaryLoader.Arguments();
var file = new MultiFileSource(args.filename);
var loadSettings = ScikitSubComponent <ILegacyDataLoader, SignatureDataLoader> .AsSubComponent(args.loaderSettings);
IDataView loader = loadSettings.CreateInstance(env, file);
var ag = new TagViewTransform.Arguments {
tag = args.selectTag
};
var newInput = new TagViewTransform(env, ag, loader);
var tagged = input as ITaggedDataView;
if (tagged == null)
{
ag = new TagViewTransform.Arguments {
tag = args.tag
};
tagged = new TagViewTransform(env, ag, input);
}
newInput.AddRange(new[] { new Tuple <string, ITaggedDataView>(args.tag, tagged) });
tagged.AddRange(new[] { new Tuple <string, ITaggedDataView>(args.selectTag, newInput) });
var schema = loader.Schema;
if (schema.Count == 0)
{
throw env.Except("The loaded view '{0}' is empty (empty schema).", args.filename);
}
return(newInput);
}
}