[Bug 549] New - NullPointerException when resolving external entities

[bu...@apache.org]

http://nagoya.apache.org/bugzilla/show_bug.cgi?id=549

*** shadow/549	Thu Feb  8 06:46:19 2001
--- shadow/549.tmp.10544	Thu Feb  8 06:46:19 2001
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*** 0 ****
--- 1,73 ----
+ +============================================================================+
+ | NullPointerException when resolving external entities                      |
+ +----------------------------------------------------------------------------+
+ |        Bug #: 549                         Product: Xerces-J                |
+ |       Status: NEW                         Version: unspecified             |
+ |   Resolution:                            Platform: All                     |
+ |     Severity: Normal                   OS/Version: All                     |
+ |     Priority:                           Component: Core                    |
+ +----------------------------------------------------------------------------+
+ |  Assigned To: xerces-dev@xml.apache.org                                    |
+ |  Reported By: blais@odi.com                                                |
+ |      CC list: Cc:                                                          |
+ +----------------------------------------------------------------------------+
+ |          URL:                                                              |
+ +============================================================================+
+ |                              DESCRIPTION                                   |
+ There is a bug in the StringPool class that we see when we try to resolve
+ external entities and the top level source is an InputStream instead of a
+ SystemID. In other words, using 
+ 
+  org.apache.xerces.parsers.DOMParser.parse(new InputSource(InputStream))
+ 
+ Fails while
+ 
+  org.apache.xerces.parsers.DOMParser(new InputSource(systemID)) works.
+ 
+ I tracked this down to the StringPool.addSymbol() method.  I believe
+ that since the InputSource(InputStream) never sets it's systemId, it 
+ is null. So when this is passed into addSymbol() the exception occurs.
+ 
+ It seems that the null should be a valid value so I fixed this locally
+ by patching the code. 
+ 
+ Originally found in version 1_2_0 but also in 1_2_3 and 1_3_0.
+ 
+ 
+ In org/apache/xerces/readersDefaultEntityHandler.java, this addSymbol
+ (fSystemId) on line 226 hits the bug.
+ 
+       public int addExternalEntityDecl(int name, int publicId, int systemId, 
+ boolean isExternal) throws Exception {
+ 
+ !         int entityHandle = fEntityPool.addEntityDecl(name, -1, publicId, 
+ systemId, fStringPool.addSymbol(fSystemId), -1, isExternal);
+ 
+           return entityHandle;
+ 
+       }
+ 
+ 
+ 
+ fSystemId is null which is perfectly acceptable. But when addSymbol(...) tries
+ to get the length, a NullPointerException is raised. I believe there are other
+ cases where a null could be passed in to addSymbol(). So I added a check to
+ make sure null is acceptable.  NULL_STRING is the index to the null string.
+ 
+ 
+  diff -cw ./src/org/apache/xerces/utils/StringPool.java ../xerces-
+ 1_2_3/src/org/apache/xerces/utils/StringPool.java
+ *** ./src/org/apache/xerces/utils/StringPool.java	Wed Jan 31 20:11:30 2001
+ --- ../xerces-1_2_3/src/org/apache/xerces/utils/StringPool.java	Fri Jan 26 
+ 17:38:24 2001
+ ***************
+ *** 345,350 ****
+ --- 345,352 ----
+           }
+       }
+       public int addSymbol(String str) {
+ +         if( str == null )
+ + 	  return NULL_STRING;
+           int slen = str.length();
+           int hashcode = StringHasher.hashString(str, slen);
+           int hc = hashcode % HASHTABLE_SIZE;