xmlsecurity: add some more logging

We only get:

warn:xmlsecurity.xmlsec:32272:32272:xmlsecurity/source/xmlsec/errorcallback.cxx:53: digests.c:226: xmlSecNssDigestVerify() 'sha1' '' 12 'data and digest do not match'

when one of the XML streams have a bad hash. Add some logging to help
figuring out (without a debugger) which stream is at fault.

Change-Id: Ib5f39df87bcdaaac1a21eb560c8f775c42a4079f
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/127885
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins

xmlsecurity/source/xmlsec/xmlstreamio.cxx

@@ -28,6 +28,7 @@
 #include <rtl/ustring.hxx>
 #include <rtl/uri.hxx>
 #include <comphelper/scopeguard.hxx>
+#include <sal/log.hxx>
 
 #include <com/sun/star/xml/crypto/XUriBinding.hpp>
 
@@ -63,6 +64,8 @@ static int xmlStreamMatch( const char* uri )
                 OUString::createFromAscii(uri));
         }
     }
+    SAL_INFO("xmlsecurity.xmlsec",
+             "xmlStreamMath: uri is '" << uri << "', returning " << xInputStream.is());
     if (xInputStream.is())
         return 1;
     else
@@ -95,6 +98,8 @@ static void* xmlStreamOpen( const char* uri )
             css::io::XInputStream* pInputStream ;
             pInputStream = xInputStream.get() ;
             pInputStream->acquire() ;
+            SAL_INFO("xmlsecurity.xmlsec",
+                     "xmlStreamOpen: uri is '" << uri << "', returning context " << pInputStream);
             return static_cast<void*>(pInputStream) ;
         }
     }
@@ -123,6 +128,8 @@ static int xmlStreamRead( void* context, char* buffer, int len )
         }
     }
 
+    SAL_INFO("xmlsecurity.xmlsec", "xmlStreamRead: context is " << context << ", buffer is now '"
+                                                         << OString(buffer, numbers) << "'");
     return numbers ;
 }
 
@@ -134,6 +141,7 @@ static int xmlStreamClose( void * context )
             css::io::XInputStream* pInputStream ;
             pInputStream = static_cast<css::io::XInputStream*>(context);
             pInputStream->release() ;
+            SAL_INFO("xmlsecurity.xmlsec", "xmlStreamRead: closed context " << context);
         }
     }