Hi, Ok. I think i found the answer by trial and error myself. I was not able to look up the named templates in the hash table for the (pre-) compiled templates.
So i followed Nick's suggest and came up with this first draft: https://github.com/GNOME/libxslt/pull/1 I tested locally and didn't get any surprises. I also created a simple test with 2 named templates that have the same name to test for collision detection. The new code behaves in that case as the previous one. But so far I have no idea yet where and how to add it to the tests in the test suite as this is a test for failure detection. Looking at a second glance at the imports.c and xsltFindTemplate i think it would be worthwhile to add the new function i created for lookup in the hash table in the file imports.c and try to encapsulate the behavior there. Do you think i should refactor the code in that direction? Best regards, Christian On Thu, Aug 20, 2015 at 10:28 AM, Christian Ceelen < christian.cee...@gmail.com> wrote: > Hi Nick, > > Thank you very much for the answer. That sounds like a very good idea. Yet > would the validation still be correct, if the hashtable is local to the > stylesheet in which the template was defined? I was wondering what would > happen if the same template name is defined in two files, where one of the > files then imports or includes the other. Concerning the imports i think > the standard is clear, the defined template has lower preference, so having > two with the same name sounds legit to me. But what happens when the file > is included? > My current understanding is that real validation requires to walk the > include tree for each template name. Would that be correctly replicating > the existing behavior? > > Btw. In xsltInernals.h:L1514 i found in struct _xsltStylesheet: > void *templatesHash; > Is this table already containing what we want? > > Best regards, > > Christian > > On Wed, Aug 19, 2015 at 1:00 PM, Nick Wellnhofer <wellnho...@aevum.de> > wrote: > >> On 19/08/2015 10:47, Christian Ceelen wrote: >> >>> At the moment i do not have a deep understanding of the libXSLT code. My >>> current guess is, that this point at which the template name is >>> validated to >>> be unique in the stylesheet. The current algorithm seems to be walking >>> linearly through the list of all already created templates and is >>> comparing >>> the name with each. Given that the compilation process is walking >>> through all >>> templates this loop means that we have an O(n^2) algorithm (with n being >>> the >>> number of template instances in the stylesheet to compile). >>> The huge number of templates in my XSLTs are just so far over the edge, >>> that >>> the compilation takes 35s. I ran a test in which i skipped the loop. This >>> reduced the compilation time to below 2.5 s. >>> >>> Would anyone let me know if i have understood the code? What can i do to >>> improve the code that would get easily accepted and released? I am open >>> to any >>> kind of suggestions on what to do to speed this validation step up with >>> a data >>> structure or mechanism already existing ? >>> >> >> Yes, template names are verified by searching a linked list which is >> O(n^2). Template lookup by name uses the same list: >> >> https://github.com/GNOME/libxslt/blob/master/libxslt/imports.c#L375 >> >> It shouldn't be too hard to change the code to use an xmlHashTable: >> >> https://github.com/GNOME/libxml2/blob/master/include/libxml/hash.h >> >> Simply add a the hash table to struct _xsltStylesheet >> >> >> https://github.com/GNOME/libxslt/blob/master/libxslt/xsltInternals.h#L1509 >> >> add some initialization and cleanup, then use xmlHashAddEntry2 and >> xmlHashLookup2 with the template's name and namespace URI. This should make >> name verification O(n) overall and lookup of a single template by name O(1). >> >> What is now the developer or working repository for libxslt? >>> I found the git repository on git.gnome.org <http://git.gnome.org>, the >>> GNOME/libxslt on github, plus several forks which seem to be working >>> repos. >>> Can you point me please to the repo against which i should use for >>> further >>> investigation or patches? >>> >> >> The official repo is the one at git.gnome.org: >> >> https://git.gnome.org/browse/libxslt/ >> >> Nick >> >> _______________________________________________ >> xslt mailing list, project page http://xmlsoft.org/XSLT/ >> xslt@gnome.org >> https://mail.gnome.org/mailman/listinfo/xslt >> > >
_______________________________________________ xslt mailing list, project page http://xmlsoft.org/XSLT/ xslt@gnome.org https://mail.gnome.org/mailman/listinfo/xslt
