Hello,
Here is the patch for contrib/xml2 (attached), that:
- renames xml_valid() to xml_is_well_formed()
- adds PG_MODULE_MAGIC; at the beginning of xpath.c
- introduces xpath_array() function
- adds some words about that function and caution about libraries to README
I understand that it's too late, but xpath_array() is pretty simple
function (and, actually, this is a tiny step to XQuery sequences).
Besides that, it is mentioned in the current TODO list and I've told
about this before. Actually, this is at least some [minor] addition for
this module for 8.2.
Let me know if I can help somehow else in this direction.
--
Best regards,
Nikolay
Index: README.xml2
===================================================================
RCS file: /projects/cvsroot/pgsql/contrib/xml2/README.xml2,v
retrieving revision 1.6
diff -u -r1.6 README.xml2
--- README.xml2 25 Aug 2006 23:45:02 -0000 1.6
+++ README.xml2 5 Sep 2006 21:51:23 -0000
@@ -21,14 +21,16 @@
Before you begin, just check the Makefile, and then just 'make' and
'make install'.
-This code requires libxml to be previously installed.
+By default, this module requires both libxml2 and libxslt installed
+on your system. If you do not have libxslt or do not want to use XSLT
+functions, you should edit Makefile to remove mentioning of XSLT.
Description of functions
------------------------
The first set of functions are straightforward XML parsing and XPath queries:
-xml_valid(document) RETURNS bool
+xml_is_well_formed(document) RETURNS bool
This parses the document text in its parameter and returns true if the
document is well-formed XML.
@@ -67,6 +69,12 @@
This is a wrapper for the above function that uses ',' as the seperator.
+xpath_array(document,query) RETURNS text[]
+
+This function returns array of text values. In common case, XPath
+evaluation produces a set of values (a set of strings, a set of integers
+or a set of XML chunks). Text array returned by this functions corresponds
+to that set of values.
xpath_table
-----------
Index: pgxml.sql.in
===================================================================
RCS file: /projects/cvsroot/pgsql/contrib/xml2/pgxml.sql.in,v
retrieving revision 1.8
diff -u -r1.8 pgxml.sql.in
--- pgxml.sql.in 27 Feb 2006 16:09:49 -0000 1.8
+++ pgxml.sql.in 5 Sep 2006 21:51:23 -0000
@@ -1,6 +1,6 @@
--SQL for XML parser
-CREATE OR REPLACE FUNCTION xml_valid(text) RETURNS bool
+CREATE OR REPLACE FUNCTION xml_is_well_formed(text) RETURNS bool
AS 'MODULE_PATHNAME' LANGUAGE C STRICT IMMUTABLE;
CREATE OR REPLACE FUNCTION xml_encode_special_chars(text) RETURNS text
@@ -24,6 +24,10 @@
AS 'MODULE_PATHNAME'
LANGUAGE C STRICT IMMUTABLE;
+-- Array returning XPath function
+CREATE OR REPLACE FUNCTION xpath_array(text,text) RETURNS _text
+ AS 'MODULE_PATHNAME' LANGUAGE C STRICT IMMUTABLE;
+
CREATE OR REPLACE FUNCTION xpath_list(text,text) RETURNS text
AS 'SELECT xpath_list($1,$2,'','')' LANGUAGE SQL STRICT IMMUTABLE;
@@ -46,15 +50,3 @@
AS 'MODULE_PATHNAME'
LANGUAGE C STRICT STABLE;
--- XSLT functions
--- Delete from here to the end of the file if you are not compiling with
--- XSLT support.
-
-
-CREATE OR REPLACE FUNCTION xslt_process(text,text,text) RETURNS text
- AS 'MODULE_PATHNAME' LANGUAGE C STRICT VOLATILE;
-
--- the function checks for the correct argument count
-
-CREATE OR REPLACE FUNCTION xslt_process(text,text) RETURNS text
- AS 'MODULE_PATHNAME' LANGUAGE C STRICT IMMUTABLE;
Index: xpath.c
===================================================================
RCS file: /projects/cvsroot/pgsql/contrib/xml2/xpath.c,v
retrieving revision 1.11
diff -u -r1.11 xpath.c
--- xpath.c 23 May 2006 15:21:51 -0000 1.11
+++ xpath.c 5 Sep 2006 21:51:24 -0000
@@ -16,6 +16,8 @@
#include <libxml/xmlerror.h>
#include <libxml/parserInternals.h>
+PG_MODULE_MAGIC;
+
/* declarations */
static void *pgxml_palloc(size_t size);
@@ -30,6 +32,8 @@
static xmlChar *pgxmlNodeSetToText(xmlNodeSetPtr nodeset,
xmlChar * toptagname, xmlChar * septagname,
xmlChar * plainsep);
+
+text *pgxml_node_dump_to_text(xmlNodePtr cur);
text *pgxml_result_to_text(xmlXPathObjectPtr res, xmlChar * toptag,
xmlChar * septag, xmlChar * plainsep);
@@ -38,14 +42,14 @@
static xmlXPathObjectPtr pgxml_xpath(text *document, xmlChar * xpath);
-
-Datum xml_valid(PG_FUNCTION_ARGS);
+Datum xml_is_well_formed(PG_FUNCTION_ARGS);
Datum xml_encode_special_chars(PG_FUNCTION_ARGS);
Datum xpath_nodeset(PG_FUNCTION_ARGS);
Datum xpath_string(PG_FUNCTION_ARGS);
Datum xpath_number(PG_FUNCTION_ARGS);
Datum xpath_bool(PG_FUNCTION_ARGS);
Datum xpath_list(PG_FUNCTION_ARGS);
+Datum xpath_array(PG_FUNCTION_ARGS);
Datum xpath_table(PG_FUNCTION_ARGS);
/* Global variables */
@@ -163,12 +167,12 @@
/* Returns true if document is well-formed */
-PG_FUNCTION_INFO_V1(xml_valid);
+PG_FUNCTION_INFO_V1(xml_is_well_formed);
Datum
-xml_valid(PG_FUNCTION_ARGS)
+xml_is_well_formed(PG_FUNCTION_ARGS)
{
- /* called as xml_valid(document) */
+ /* called as xml_is_well_formed(document) */
xmlDocPtr doctree;
text *t = PG_GETARG_TEXT_P(0); /* document buffer */
int32 docsize = VARSIZE(t) - VARHDRSZ;
@@ -513,7 +517,56 @@
}
+/*
+ * Evaluate XPath expression and return array of XML chunks (array of text values)
+ */
+PG_FUNCTION_INFO_V1(xpath_array);
+Datum
+xpath_array(PG_FUNCTION_ARGS)
+{
+ xmlXPathObjectPtr xpathobj;
+ ArrayBuildState *astate = NULL;
+ xmlChar *xpath;
+ int i;
+ int32 pathsize;
+ text *xpathsupp;
+
+ /* PG_GETARG_TEXT_P(0) is document buffer */
+ xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
+ pathsize = VARSIZE(xpathsupp) - VARHDRSZ;
+ xpath = pgxml_texttoxmlchar(xpathsupp);
+
+ xpathobj = pgxml_xpath(PG_GETARG_TEXT_P(0), xpath);
+ if (xpathobj == NULL
+ || xpathobj->nodesetval == NULL
+ || xpathobj->nodesetval->nodeNr == 0)
+ {
+ /* Note, that throwing ERROR might be more proper solution
+ here (at least in one of these three cases);
+ meanwhile, keep silence here, as in other xpath_*() functions */
+ xmlCleanupParser();
+ PG_RETURN_NULL();
+ }
+
+ for (i = 0; i < xpathobj->nodesetval->nodeNr; i++)
+ {
+ xmlChar *str;
+ text *txt;
+ Datum elem;
+ bool elemisnull = false;
+ txt = pgxml_node_dump_to_text(xpathobj->nodesetval->nodeTab[i]);
+ elem = PointerGetDatum(txt);
+ astate = accumArrayResult(astate, elem,
+ elemisnull, TEXTOID,
+ CurrentMemoryContext);
+ }
+
+ xmlXPathFreeObject(xpathobj);
+ xmlCleanupParser();
+
+ PG_RETURN_ARRAYTYPE_P(makeArrayResult(astate, CurrentMemoryContext));
+}
/* Core function to evaluate XPath query */
@@ -623,6 +676,27 @@
return xpres;
}
+/* dumps XML node to text (serialization) */
+text *
+pgxml_node_dump_to_text(xmlNodePtr cur)
+{
+ xmlBufferPtr buf;
+ xmlChar *str;
+ text *result;
+ size_t len;
+
+ buf = xmlBufferCreate();
+ xmlNodeDump(buf, cur->doc, cur, 1, 0);
+ str = xmlStrdup(buf->content);
+ xmlBufferFree(buf);
+ len = strlen(str);
+ result = (text *) palloc(len + VARHDRSZ);
+ VARATT_SIZEP(result) = len + VARHDRSZ;
+ memcpy(VARDATA(result), str, len);
+
+ return result;
+}
+
/* xpath_table is a table function. It needs some tidying (as do the
* other functions here!
*/
---------------------------(end of broadcast)---------------------------
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