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Support arrays as input to array_agg() and ARRAY(SELECT ...).

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These cases formerly failed with errors about "could not find array type
for data type".  Now they yield arrays of the same element type and one
higher dimension.

The implementation involves creating functions with API similar to the
existing accumArrayResult() family.  I (tgl) also extended the base family
by adding an initArrayResult() function, which allows callers to avoid
special-casing the zero-inputs case if they just want an empty array as
result.  (Not all do, so the previous calling convention remains valid.)
This allowed simplifying some existing code in xml.c and plperl.c.

Ali Akbar, reviewed by Pavel Stehule, significantly modified by me
This commit is contained in:
Tom Lane
2014-11-25 12:21:22 -05:00
parent 25976710df
commit bac27394a1
18 changed files with 797 additions and 115 deletions
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31
src/backend/utils/adt/xml.c
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@ -143,7 +143,7 @@ static xmlDocPtr xml_parse(text *data, XmlOptionType xmloption_arg,
bool preserve_whitespace, int encoding);
static text *xml_xmlnodetoxmltype(xmlNodePtr cur);
static int xml_xpathobjtoxmlarray(xmlXPathObjectPtr xpathobj,
ArrayBuildState **astate);
ArrayBuildState *astate);
#endif /* USE_LIBXML */
static StringInfo query_to_xml_internal(const char *query, char *tablename,
@ -3648,7 +3648,7 @@ xml_xmlnodetoxmltype(xmlNodePtr cur)
/*
* Convert an XML XPath object (the result of evaluating an XPath expression)
* to an array of xml values, which is returned at *astate. The function
* to an array of xml values, which are appended to astate. The function
* result value is the number of elements in the array.
*
* If "astate" is NULL then we don't generate the array value, but we still
@ -3660,16 +3660,13 @@ xml_xmlnodetoxmltype(xmlNodePtr cur)
*/
static int
xml_xpathobjtoxmlarray(xmlXPathObjectPtr xpathobj,
ArrayBuildState **astate)
ArrayBuildState *astate)
{
int result = 0;
Datum datum;
Oid datumtype;
char *result_str;
if (astate != NULL)
*astate = NULL;
switch (xpathobj->type)
{
case XPATH_NODESET:
@ -3683,9 +3680,8 @@ xml_xpathobjtoxmlarray(xmlXPathObjectPtr xpathobj,
for (i = 0; i < result; i++)
{
datum = PointerGetDatum(xml_xmlnodetoxmltype(xpathobj->nodesetval->nodeTab[i]));
*astate = accumArrayResult(*astate, datum,
false, XMLOID,
CurrentMemoryContext);
(void) accumArrayResult(astate, datum, false,
XMLOID, CurrentMemoryContext);
}
}
}
@ -3721,9 +3717,8 @@ xml_xpathobjtoxmlarray(xmlXPathObjectPtr xpathobj,
/* Common code for scalar-value cases */
result_str = map_sql_value_to_xml_value(datum, datumtype, true);
datum = PointerGetDatum(cstring_to_xmltype(result_str));
*astate = accumArrayResult(*astate, datum,
false, XMLOID,
CurrentMemoryContext);
(void) accumArrayResult(astate, datum, false,
XMLOID, CurrentMemoryContext);
return 1;
}
@ -3741,7 +3736,7 @@ xml_xpathobjtoxmlarray(xmlXPathObjectPtr xpathobj,
*/
static void
xpath_internal(text *xpath_expr_text, xmltype *data, ArrayType *namespaces,
int *res_nitems, ArrayBuildState **astate)
int *res_nitems, ArrayBuildState *astate)
{
PgXmlErrorContext *xmlerrcxt;
volatile xmlParserCtxtPtr ctxt = NULL;
@ -3933,16 +3928,12 @@ xpath(PG_FUNCTION_ARGS)
text *xpath_expr_text = PG_GETARG_TEXT_P(0);
xmltype *data = PG_GETARG_XML_P(1);
ArrayType *namespaces = PG_GETARG_ARRAYTYPE_P(2);
int res_nitems;
ArrayBuildState *astate;
astate = initArrayResult(XMLOID, CurrentMemoryContext);
xpath_internal(xpath_expr_text, data, namespaces,
&res_nitems, &astate);
if (res_nitems == 0)
PG_RETURN_ARRAYTYPE_P(construct_empty_array(XMLOID));
else
PG_RETURN_ARRAYTYPE_P(makeArrayResult(astate, CurrentMemoryContext));
NULL, astate);
PG_RETURN_ARRAYTYPE_P(makeArrayResult(astate, CurrentMemoryContext));
#else
NO_XML_SUPPORT();
return 0;