Hi Alberto,
Looks like we are both working on the same problem. I have a different
solution for #1 and that is to call switchGrammar in scanDocType. That is
what happens in IGXMLScanner but not DGXMLScanner and that is why it works
for IG and not DG.
For #2, still looking at how to avoid the 2nd call. Another customer
reported a similar problem as this as well...
Regards,
David A. Cargill
XML Parser Development
IBM Toronto Lab
(905) 413-2371, tie 969
[EMAIL PROTECTED]
Alberto Massari
<[EMAIL PROTECTED]
s.com> To
[EMAIL PROTECTED]
12/03/2004 11:51 cc
AM
Subject
Re: DTD caching problems
Please respond to
xerces-c-dev
Hi Daniel,
I have looked at the testcase you submitted, and I found two things:
1) the exception you get when using cached grammars and the DGXMLScanner is
caused by GrammarResolver::orphanGrammar; to fix it, apply this diff
diff -u -r1.29 GrammarResolver.cpp
--- GrammarResolver.cpp 29 Sep 2004 19:27:07 -0000 1.29
+++ GrammarResolver.cpp 3 Dec 2004 16:16:23 -0000
@@ -439,7 +439,8 @@
Grammar* grammar = fGrammarPool->orphanGrammar(nameSpaceKey);
if (grammar)
{
- fGrammarFromPool->removeKey(nameSpaceKey);
+ if (fGrammarFromPool->containsKey(nameSpaceKey))
+ fGrammarFromPool->removeKey(nameSpaceKey);
return grammar;
}
// It failed to remove it from the grammar pool either because it
2) as for the extra resolveEntity() you see, it's by design;
GrammarResolver now stores the DTDs using their systemID as key (instead of
the root element name), so, when caching is on, an extra call to
resolveEntity is done in order to be able to invoke
InputSource::getSystemId(). At that point, if the systemId is already in
the cache, the input source is not parsed; if it is not in the cache, a new
reader is created (and this triggers a new resolveEntity call)
I will change this to at least avoid the second call (as we have already
resolved the DTD).
Thanks for the testcase,
Alberto
At 16.42 03/12/2004 +1100, Daniel McLean wrote:
>I've put together a demo based on one of the sample programs shipped with
>Xerces. The demo creates a Xerces GrammarPoolImpl then conducts a number
>of validating XML parses using that grammar pool when caching is enabled
>for the parser. The test documents include an XML file referring to a DTD
>and an XML file referring to an XML schema. Each type of parse is done
>twice in succession to observe the caching behaviour of Xerces, with a new
>parser instance created for each parse. The parses done include:
>
> DGXMLScanner without caching involving DTD validation
> DGXMLScanner with caching involving DTD validation
>
> IGXMLScanner without caching involving DTD validation
> IGXMLScanner with caching involving DTD validation
>
> SGXMLScanner without caching involving XML schema validation
> SGXMLScanner with caching involving XML schema validation
>
>I ran with on an Fedora Core 1 linux x86 platform using Xerces 2.6.0.
>
>I see a number of surprising things (refer to output below):
> - parsing fails when caching is enabled whilst using the DGXMLScanner
> - when using DGXMLScanner or IGXMLScanner for DTD validation, the DTD
> appears to be re-resolved for each parse. I haven't checked whether
> the DTD is actually being re-parsed after being resolved each time,
but
> I wonder why it is being resolved each time if it is supposedly being
> cached
> - the DTD is being resolved twice on the first parse when parsing with a
> DTD and caching enabled. This seems questionable.
>
>I've attached a tarball containing the files for the demo, which should
>work after being unpacked into the samples directory.
>
>Regards,
>
>Daniel
>
>doParse dtdDGXML
>parse #1
>resolveEntity("", "example.dtd")
>parse #2
>resolveEntity("", "example.dtd")
>----------------------------
>doParse dtdDGXMLCaching
>parse #1
>resolveEntity(null, "example.dtd")
>resolveEntity("", "example.dtd")
>
>Fatal Error at (file
>/home/daniel/xerces/xerces-c-src_2_6_0/samples/GrammarCache/example-dtd.xml,
>line 2, char 40): An exception occurred! Type:NoSuchElementException,
>Message:The key '{0}' could not be found in the hash table
>parse #2
>resolveEntity(null, "example.dtd")
>resolveEntity("", "example.dtd")
>
>Fatal Error at (file
>/home/daniel/xerces/xerces-c-src_2_6_0/samples/GrammarCache/example-dtd.xml,
>line 2, char 40): An exception occurred! Type:NoSuchElementException,
>Message:The key '{0}' could not be found in the hash table
>----------------------------
>doParse dtdIGXML
>parse #1
>resolveEntity("", "example.dtd")
>parse #2
>resolveEntity("", "example.dtd")
>----------------------------
>doParse dtdIGXMLCaching
>parse #1
>resolveEntity("", "example.dtd")
>resolveEntity("", "example.dtd")
>parse #2
>resolveEntity("", "example.dtd")
>----------------------------
>doParse xsd
>parse #1
>resolveEntity("", "example.xsd")
>parse #2
>resolveEntity("", "example.xsd")
>----------------------------
>doParse xsdCaching
>parse #1
>resolveEntity("", "example.xsd")
>parse #2
>----------------------------
>
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