Allow XML fragment to contain a XML declaration. For that, we need a small

hand-crafted parser for the XML declaration, because libxml doesn't seem
to allow this.

diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index ab929eed64720308428a971193373308268170b9..597ba4f7137fcb35687cd15bfe275e788ce3374a 100644 (file)
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/utils/adt/xml.c,v 1.11 2007/01/06 19:18:36 petere Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/xml.c,v 1.12 2007/01/07 00:13:55 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -489,6 +489,122 @@ xml_init(void)
 }
 
 
+/*
+ * SQL/XML allows storing "XML documents" or "XML content".  "XML
+ * documents" are specified by the XML specification and are parsed
+ * easily by libxml.  "XML content" is specified by SQL/XML as the
+ * production "XMLDecl? content".  But libxml can only parse the
+ * "content" part, so we have to parse the XML declaration ourselves
+ * to complete this.
+ */
+
+#define CHECK_XML_SPACE(p) if (!xmlIsBlank_ch(*(p))) return XML_ERR_SPACE_REQUIRED
+#define SKIP_XML_SPACE(p) while (xmlIsBlank_ch(*(p))) (p)++
+
+static int
+parse_xml_decl(const xmlChar *str, size_t *len, xmlChar **encoding, int *standalone)
+{
+   const xmlChar *p;
+   const xmlChar *save_p;
+
+   p = str;
+
+   if (xmlStrncmp(p, (xmlChar *)"<?xml", 5) != 0)
+       goto finished;
+
+   p += 5;
+
+   /* version */
+   CHECK_XML_SPACE(p);
+   SKIP_XML_SPACE(p);
+   if (xmlStrncmp(p, (xmlChar *)"version", 7) != 0)
+       return XML_ERR_VERSION_MISSING;
+   p += 7;
+   SKIP_XML_SPACE(p);
+   if (*p != '=')
+       return XML_ERR_VERSION_MISSING;
+   p += 1;
+   SKIP_XML_SPACE(p);
+   if (xmlStrncmp(p, (xmlChar *)"'1.0'", 5) != 0 && xmlStrncmp(p, (xmlChar *)"\"1.0\"", 5) != 0)
+       return XML_ERR_VERSION_MISSING;
+   p += 5;
+
+   /* encoding */
+   save_p = p;
+   SKIP_XML_SPACE(p);
+   if (xmlStrncmp(p, (xmlChar *)"encoding", 8) == 0)
+   {
+       CHECK_XML_SPACE(save_p);
+       p += 8;
+       SKIP_XML_SPACE(p);
+       if (*p != '=')
+           return XML_ERR_MISSING_ENCODING;
+       p += 1;
+       SKIP_XML_SPACE(p);
+
+       if (*p == '\'' || *p == '"')
+       {
+           const xmlChar *q;
+
+           q = xmlStrchr(p + 1, *p);
+           if (!q)
+               return XML_ERR_MISSING_ENCODING;
+
+           *encoding = xmlStrndup(p + 1, q - p - 1);
+           p = q + 1;
+       }
+       else
+           return XML_ERR_MISSING_ENCODING;
+   }
+   else
+   {
+       p = save_p;
+       *encoding = NULL;
+   }
+
+   /* standalone */
+   save_p = p;
+   SKIP_XML_SPACE(p);
+   if (xmlStrncmp(p, (xmlChar *)"standalone", 10) == 0)
+   {
+       CHECK_XML_SPACE(save_p);
+       p += 10;
+       SKIP_XML_SPACE(p);
+       if (*p != '=')
+           return XML_ERR_STANDALONE_VALUE;
+       p += 1;
+       SKIP_XML_SPACE(p);
+       if (xmlStrncmp(p, (xmlChar *)"'yes'", 5) == 0 || xmlStrncmp(p, (xmlChar *)"\"yes\"", 5) == 0)
+       {
+           *standalone = 1;
+           p += 5;
+       }
+       else if (xmlStrncmp(p, (xmlChar *)"'no'", 4) == 0 || xmlStrncmp(p, (xmlChar *)"\"no\"", 4) == 0)
+       {
+           *standalone = 0;
+           p += 4;
+       }
+       else
+           return XML_ERR_STANDALONE_VALUE;
+   }
+   else
+   {
+       p = save_p;
+       *standalone = -1;
+   }
+
+   SKIP_XML_SPACE(p);
+   if (xmlStrncmp(p, (xmlChar *)"?>", 2) != 0)
+       return XML_ERR_XMLDECL_NOT_FINISHED;
+   p += 2;
+
+finished:
+   if (len)
+       *len = (p - str);
+   return XML_ERR_OK;
+}
+
+
 /*
  * Convert a C string to XML internal representation
  *
@@ -536,19 +652,23 @@ xml_parse(text *data, bool is_document, bool preserve_whitespace)
        }
        else
        {
+           size_t count;
+           xmlChar *encoding = NULL;
+           int standalone = -1;
+
            doc = xmlNewDoc(NULL);
 
-           /*
-            * FIXME: An XMLDecl is supposed to be accepted before the
-            * content, but libxml doesn't allow this.  Parse that
-            * ourselves?
-            */
+           res_code = parse_xml_decl(string, &count, &encoding, &standalone);
 
            /* TODO resolve: xmlParseBalancedChunkMemory assumes that string is UTF8 encoded! */
-           res_code = xmlParseBalancedChunkMemory(doc, NULL, NULL, 0, string, NULL);
+           if (res_code == 0)
+               res_code = xmlParseBalancedChunkMemory(doc, NULL, NULL, 0, string + count, NULL);
            if (res_code != 0)
                xml_ereport_by_code(ERROR, ERRCODE_INVALID_XML_CONTENT,
                                    "invalid XML content", res_code);
+
+           doc->encoding = encoding;
+           doc->standalone = standalone;
        }
 
        /* TODO encoding issues