[xml] Patch for XML declaration detection (standalone=-2)

[Michael Day <mikeday yeslogic com>]

Hi,

Here is a patch that fixes a minor bug in my earlier patch that enabled 
detection of whether an XML declaration was specified. It also adds some 
documentation explaining the different values of "standalone":

 standalone=1   ---> standalone="yes"
 standalone=0   ---> standalone="no"
 standalone=-1  ---> no XML declaration
 standalone=-2  ---> XML declaration, but no standalone attribute

The use case for all this is that I wish to use the XML reader, read up 
to the start tag of the root element, and then check the standalone 
value in order to see if an XML declaration was seen. This is in order 
to do content sniffing between XML and HTML.

The bug was that standalone was defaulting to -1 instead of -2 in 
xmlParseSDDecl, even though if we get to xmlParseSDDecl it means that an 
XML declaration has been seen. It was only triggering in situations like 
this:

<?xml version="1.0"  ?>

note the space after the version attribute, which was causing 
xmlParseSDDecl to be called, then straight away returning -1, as no 
standalone attribute was found. Now it returns -2, indicating that no 
standalone attribute was found, but the XML declaration is present.

Michael


Index: parser.c
===================================================================
RCS file: /cvs/gnome/libxml2/parser.c,v
retrieving revision 1.462
diff -u -r1.462 parser.c
--- parser.c    15 Oct 2006 20:32:48 -0000      1.462
+++ parser.c    4 Dec 2006 00:05:50 -0000
@@ -8925,12 +8925,17 @@
  *  - element types with element content, if white space occurs directly
  *    within any instance of those types.
  *
- * Returns 1 if standalone, 0 otherwise
+ * Returns:
+ *   1 if standalone="yes"
+ *   0 if standalone="no"
+ *  -2 if standalone attribute is missing or invalid
+ *       (A standalone value of -2 means that the XML declaration was found,
+ *        but no value was specified for the standalone attribute).
  */

 int
 xmlParseSDDecl(xmlParserCtxtPtr ctxt) {
-    int standalone = -1;
+    int standalone = -2;

     SKIP_BLANKS;
     if (CMP10(CUR_PTR, 's', 't', 'a', 'n', 'd', 'a', 'l', 'o', 'n', 
'e')) {
Index: include/libxml/tree.h
===================================================================
RCS file: /cvs/gnome/libxml2/include/libxml/tree.h,v
retrieving revision 1.154
diff -u -r1.154 tree.h
--- include/libxml/tree.h       25 Oct 2006 16:06:29 -0000      1.154
+++ include/libxml/tree.h       4 Dec 2006 00:05:50 -0000
@@ -503,7 +503,12 @@

     /* End of common part */
     int             compression;/* level of zlib compression */
-    int             standalone; /* standalone document (no external 
refs) */
+    int             standalone; /* standalone document (no external refs)
+                                    1 if standalone="yes"
+                                    0 if standalone="no"
+                                   -1 if there is no XML declaration
+                                   -2 if there is an XML declaration, but no
+                                       standalone attribute was specified */
     struct _xmlDtd  *intSubset;        /* the document internal subset */
     struct _xmlDtd  *extSubset;        /* the document external subset */
     struct _xmlNs   *oldNs;    /* Global namespace, the old way */

Index: parser.c
===================================================================
RCS file: /cvs/gnome/libxml2/parser.c,v
retrieving revision 1.462
diff -u -r1.462 parser.c
--- parser.c    15 Oct 2006 20:32:48 -0000      1.462
+++ parser.c    4 Dec 2006 00:05:50 -0000
@@ -8925,12 +8925,17 @@
  *  - element types with element content, if white space occurs directly
  *    within any instance of those types.
  *
- * Returns 1 if standalone, 0 otherwise
+ * Returns:
+ *   1 if standalone="yes"
+ *   0 if standalone="no"
+ *  -2 if standalone attribute is missing or invalid
+ *       (A standalone value of -2 means that the XML declaration was found,
+ *        but no value was specified for the standalone attribute).
  */
 
 int
 xmlParseSDDecl(xmlParserCtxtPtr ctxt) {
-    int standalone = -1;
+    int standalone = -2;
 
     SKIP_BLANKS;
     if (CMP10(CUR_PTR, 's', 't', 'a', 'n', 'd', 'a', 'l', 'o', 'n', 'e')) {
Index: include/libxml/tree.h
===================================================================
RCS file: /cvs/gnome/libxml2/include/libxml/tree.h,v
retrieving revision 1.154
diff -u -r1.154 tree.h
--- include/libxml/tree.h       25 Oct 2006 16:06:29 -0000      1.154
+++ include/libxml/tree.h       4 Dec 2006 00:05:50 -0000
@@ -503,7 +503,12 @@
 
     /* End of common part */
     int             compression;/* level of zlib compression */
-    int             standalone; /* standalone document (no external refs) */
+    int             standalone; /* standalone document (no external refs) 
+                                    1 if standalone="yes"
+                                    0 if standalone="no"
+                                   -1 if there is no XML declaration
+                                   -2 if there is an XML declaration, but no
+                                       standalone attribute was specified */
     struct _xmlDtd  *intSubset;        /* the document internal subset */
     struct _xmlDtd  *extSubset;        /* the document external subset */
     struct _xmlNs   *oldNs;    /* Global namespace, the old way */