[xml] xml and IO

[Gary Pennington <Gary Pennington uk sun com>]

Hi,

I'm trying to add a mechanism so that any files which I open using
libxml are locked (to prevent anyone else tampering with the files as
long as my process is running). I'm attacking this problem by:

1. Defining 4 routines for match. open, close and read.
2. Adding the required code for open and close to lock and unlock the
file.

Since I don't do anything special with the file (other than lock and
close) I'd like to piggyback my code onto the existing default file
handling functions (xmlFileOpen, etc...). However, the existing file
handling functions are all defined as static.

I could copy the code from these functions into my routines and solve
the problem like that, but I don't like that approach since it is
intrinsically naff.

Would it be such a bad thing to make these various IO functions part of
the public interface so that people can easily utilise their
functionality? I know that it's a good idea to keep implementations
private where possible, but since the IO registration mechanism doesn't
support cascaded IO handling (where a number of qualifying IO functions
can all be registered) it makes sense to make these "default"
implementations available. Either that or let multiple IO handlers
register to handle IO's of certain types.

I know that the file handling routines don't do a lot, but it would be
more of a pain if you were trying to do the same (conceptual) thing for
ftp or http or whatever handlers.

OR am I attacking this problem in completely the wrong way? Is there
already some other easy mechanism for doing this that I haven't spotted?

Gary