Re: [xml] xmlreader and chunked parsing?

[Daniel Veillard <veillard redhat com>]

On Sat, Nov 01, 2003 at 08:25:59AM +0000, Nick Kew wrote:
> I regularly use the SAX API with chunked parsing ( [x|ht]mlParseChunk
> and family), as this is ideal for a pipelined processing environment
> where data are naturally available in chunks.
>
> I've had a brief look at xmlreader with a view to considering it as
> an alternative, but I haven't found anything similar.  I could in
> principle use it with something like
>
> while ( ! end ) {
>   status = [ process something in xmlreader ]
>   switch ( status ) {
>     case OK: [ process and continue ]
>     case Out of Data:
>       [ if the parser internally remains in a consistent
>         state then we can feed it another chunk and continue ]
>     other: [ handle error ]
>   }
> }
>
> The crucial question is: can I catch out-of-data whilst preserving
> internal parser state, and without significant overhead?  Is this
> realistic, or would I be wasting my time trying?

  Can't you rather generate you own I/O routine (read, close) and
use the standard I/O wrapper mechanism ?
  xmlTextReaderPtr
  xmlReaderForIO(xmlInputReadCallback ioread, xmlInputCloseCallback ioclose,
                 void *ioctx, const char *URL, const char *encoding,
                                int options)
The point of the xmlReader is precisely to simplify the consuming loop,
if you start adding again the I/O condition handling to that loop, IMHO
you loose most of the benefits of the xmlReader API.

  Internally a reader is based on a parser in chunked parsing mode, but
breaking the API to expose those condition to the event loop doesn't sound
wise to me, how is the I/O approach not right w.r.t. your problem space ?

Daniel

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