[XaraXtreme-dev] XML notes

[Phil Martin <phil@xxxxxxxx>]

If you're going to use XML via libxml2 in Camelot are some notes:

* Remember that libxml2 uses UTF-8 encoding in memory no matter what the 
program's native encoding or the encoding of the original doc. So you 
have to be careful to do correct conversion to and from UTF-8 when 
passing strring parameters to it. I used wxString for this because it 
has useful encoding conversion functions.

* Only where you *KNOW* for certain that a string is UTF-8 (e.g. a 
bound-in string, such as an attribute name, containing only 7-bit ascii 
characters) can you cast to (xmlChar*) - but doing so saves a lot of 
fiddling around!

* libxml2 provides an API called the "tree module" which similar to the 
w3c DOM does but different - slightly lower-level being based on C 
structures. Note that there are functions that take namespaces into 
account and functions that ignore namespaces - so you can choose at 
build time whether your code will be more tolerant or strict about 
namespace usage.

* I revived the CXMLUtils class from Camelot on Windows but it doesn't 
contain all the old functions - doesn't need to so far. CXMLUtils 
intialises the libxml2 parser at program startup and de-initialises at 
closedown so that it's always ready to be used while Camelot is running.

Phil