From 79af9a1d2668c9edc8171f03c39e7fed571eeb98 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter_e@gmx.net>
Date: Tue, 6 Jan 2015 23:06:13 -0500
Subject: [PATCH] Fix namespace handling in xpath function
Previously, the xml value resulting from an xpath query would not have
namespace declarations if the namespace declarations were attached to
an ancestor element in the input xml value. That means the output value
was not correct XML. Fix that by running the result value through
xmlCopyNode(), which produces the correct namespace declarations.
Author: Ali Akbar <the.apaan@gmail.com>
---
src/backend/utils/adt/xml.c | 34 ++++++++++++++++++++++-------
src/test/regress/expected/xml.out | 15 +++++++++++++
src/test/regress/expected/xml_1.out | 12 ++++++++++
src/test/regress/sql/xml.sql | 2 ++
4 files changed, 55 insertions(+), 8 deletions(-)
diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index a735aa28015..bfe9447295d 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -141,9 +141,10 @@ static bool print_xml_decl(StringInfo buf, const xmlChar *version,
pg_enc encoding, int standalone);
static xmlDocPtr xml_parse(text *data, XmlOptionType xmloption_arg,
bool preserve_whitespace, int encoding);
-static text *xml_xmlnodetoxmltype(xmlNodePtr cur);
+static text *xml_xmlnodetoxmltype(xmlNodePtr cur, PgXmlErrorContext *xmlerrcxt);
static int xml_xpathobjtoxmlarray(xmlXPathObjectPtr xpathobj,
- ArrayBuildState *astate);
+ ArrayBuildState *astate,
+ PgXmlErrorContext *xmlerrcxt);
#endif /* USE_LIBXML */
static StringInfo query_to_xml_internal(const char *query, char *tablename,
@@ -3599,26 +3600,41 @@ SPI_sql_row_to_xmlelement(int rownum, StringInfo result, char *tablename,
* return value otherwise)
*/
static text *
-xml_xmlnodetoxmltype(xmlNodePtr cur)
+xml_xmlnodetoxmltype(xmlNodePtr cur, PgXmlErrorContext *xmlerrcxt)
{
xmltype *result;
if (cur->type == XML_ELEMENT_NODE)
{
xmlBufferPtr buf;
+ xmlNodePtr cur_copy;
buf = xmlBufferCreate();
+
+ /*
+ * The result of xmlNodeDump() won't contain namespace definitions
+ * from parent nodes, but xmlCopyNode() duplicates a node along with
+ * its required namespace definitions.
+ */
+ cur_copy = xmlCopyNode(cur, 1);
+
+ if (cur_copy == NULL)
+ xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
+ "could not copy node");
+
PG_TRY();
{
- xmlNodeDump(buf, NULL, cur, 0, 1);
+ xmlNodeDump(buf, NULL, cur_copy, 0, 1);
result = xmlBuffer_to_xmltype(buf);
}
PG_CATCH();
{
+ xmlFreeNode(cur_copy);
xmlBufferFree(buf);
PG_RE_THROW();
}
PG_END_TRY();
+ xmlFreeNode(cur_copy);
xmlBufferFree(buf);
}
else
@@ -3660,7 +3676,8 @@ xml_xmlnodetoxmltype(xmlNodePtr cur)
*/
static int
xml_xpathobjtoxmlarray(xmlXPathObjectPtr xpathobj,
- ArrayBuildState *astate)
+ ArrayBuildState *astate,
+ PgXmlErrorContext *xmlerrcxt)
{
int result = 0;
Datum datum;
@@ -3679,7 +3696,8 @@ xml_xpathobjtoxmlarray(xmlXPathObjectPtr xpathobj,
for (i = 0; i < result; i++)
{
- datum = PointerGetDatum(xml_xmlnodetoxmltype(xpathobj->nodesetval->nodeTab[i]));
+ datum = PointerGetDatum(xml_xmlnodetoxmltype(xpathobj->nodesetval->nodeTab[i],
+ xmlerrcxt));
(void) accumArrayResult(astate, datum, false,
XMLOID, CurrentMemoryContext);
}
@@ -3881,9 +3899,9 @@ xpath_internal(text *xpath_expr_text, xmltype *data, ArrayType *namespaces,
* Extract the results as requested.
*/
if (res_nitems != NULL)
- *res_nitems = xml_xpathobjtoxmlarray(xpathobj, astate);
+ *res_nitems = xml_xpathobjtoxmlarray(xpathobj, astate, xmlerrcxt);
else
- (void) xml_xpathobjtoxmlarray(xpathobj, astate);
+ (void) xml_xpathobjtoxmlarray(xpathobj, astate, xmlerrcxt);
}
PG_CATCH();
{
diff --git a/src/test/regress/expected/xml.out b/src/test/regress/expected/xml.out
index 6e6c673dac5..9b2d2644146 100644
--- a/src/test/regress/expected/xml.out
+++ b/src/test/regress/expected/xml.out
@@ -612,6 +612,21 @@ SELECT xpath('//loc:piece/@id', '<local:data xmlns:local="http://127.0.0.1"><loc
{1,2}
(1 row)
+SELECT xpath('//loc:piece', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
+ xpath
+------------------------------------------------------------------------------------------------------------------------------------------------
+ {"<local:piece xmlns:local=\"http://127.0.0.1\" id=\"1\">number one</local:piece>","<local:piece xmlns:local=\"http://127.0.0.1\" id=\"2\"/>"}
+(1 row)
+
+SELECT xpath('//loc:piece', '<local:data xmlns:local="http://127.0.0.1" xmlns="http://127.0.0.2"><local:piece id="1"><internal>number one</internal><internal2/></local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
+ xpath
+--------------------------------------------------------------------------------------
+ {"<local:piece xmlns:local=\"http://127.0.0.1\" xmlns=\"http://127.0.0.2\" id=\"1\">+
+ <internal>number one</internal> +
+ <internal2/> +
+ </local:piece>","<local:piece xmlns:local=\"http://127.0.0.1\" id=\"2\"/>"}
+(1 row)
+
SELECT xpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');
xpath
-------------------------
diff --git a/src/test/regress/expected/xml_1.out b/src/test/regress/expected/xml_1.out
index b0e00671e8b..c7fa526f9cd 100644
--- a/src/test/regress/expected/xml_1.out
+++ b/src/test/regress/expected/xml_1.out
@@ -514,6 +514,18 @@ LINE 1: SELECT xpath('//loc:piece/@id', '<local:data xmlns:local="ht...
^
DETAIL: This functionality requires the server to be built with libxml support.
HINT: You need to rebuild PostgreSQL using --with-libxml.
+SELECT xpath('//loc:piece', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
+ERROR: unsupported XML feature
+LINE 1: SELECT xpath('//loc:piece', '<local:data xmlns:local="http:/...
+ ^
+DETAIL: This functionality requires the server to be built with libxml support.
+HINT: You need to rebuild PostgreSQL using --with-libxml.
+SELECT xpath('//loc:piece', '<local:data xmlns:local="http://127.0.0.1" xmlns="http://127.0.0.2"><local:piece id="1"><internal>number one</internal><internal2/></local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
+ERROR: unsupported XML feature
+LINE 1: SELECT xpath('//loc:piece', '<local:data xmlns:local="http:/...
+ ^
+DETAIL: This functionality requires the server to be built with libxml support.
+HINT: You need to rebuild PostgreSQL using --with-libxml.
SELECT xpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');
ERROR: unsupported XML feature
LINE 1: SELECT xpath('//b', '<a>one <b>two</b> three <b>etc</b></a>'...
diff --git a/src/test/regress/sql/xml.sql b/src/test/regress/sql/xml.sql
index 922ab7a604a..88764c88cdd 100644
--- a/src/test/regress/sql/xml.sql
+++ b/src/test/regress/sql/xml.sql
@@ -178,6 +178,8 @@ SELECT xpath(NULL, NULL) IS NULL FROM xmltest;
SELECT xpath('', '<!-- error -->');
SELECT xpath('//text()', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>');
SELECT xpath('//loc:piece/@id', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
+SELECT xpath('//loc:piece', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
+SELECT xpath('//loc:piece', '<local:data xmlns:local="http://127.0.0.1" xmlns="http://127.0.0.2"><local:piece id="1"><internal>number one</internal><internal2/></local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
SELECT xpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');
SELECT xpath('//text()', '<root><</root>');
SELECT xpath('//@value', '<root value="<"/>');
--
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