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 ab929ee..597ba4f 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 $
  *
  *-------------------------------------------------------------------------
  */
@@ -490,6 +490,122 @@ 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
  *
  * TODO maybe, libxml2's xmlreader is better? (do not construct DOM, yet do not use SAX - see xml_reader.c)
@@ -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