The converter's startChunkedConversion
is only called once, when the transformation is started. However, the returned sink's add
method is invoked multiple times with parts of the file.
It's up to the source to decide how big the chunks are, but a 37MB file (as mentioned in your previous question) will definitely be sent in smaller chunks.
If you want to see the chunks you can either intercept startChunkedConversion
and return a wrapped sink, or you can put yourself between the openRead
and the transformer.
Intercept:
class InterceptSink {
static int lineSplitCount = 0;
final _sink;
InterceptSink(this._sink);
add(x) {
print("InterceptSink.add Count: $lineSplitCount");
lineSplitCount++;
_sink.add(x);
}
close() { _sink.close(); }
}
class LineSplitterIntercept extends Converter {
convert(x) { throw "unimplemented"; }
startChunkedConversion(outSink) {
var lineSink = new LineSplitter().startChunkedConversion(outSink);
return new InterceptSink(lineSink);
}
}
After openRead
:
file.openRead()
.transform(UTF8.decoder)
.map(x) {
print("chunk size: ${x.length)");
return x;
}
.transform(new LineSplitter())
...