po 29. 10. 2018 v 11:45 odesílatel Pavel Stehule <[email protected]>
napsal:
>
>
> po 29. 10. 2018 v 10:11 odesílatel Pavel Stehule <[email protected]>
> napsal:
>
>> Hi
>>
>> čt 25. 10. 2018 v 21:47 odesílatel Alvaro Herrera <
>> [email protected]> napsal:
>>
>>> On 2018-Oct-25, Pavel Stehule wrote:
>>>
>>> > I am thinking so I can fix some issues related to XMLTABLE. Please,
>>> send me
>>> > more examples and test cases.
>>>
>>> Please see Markus Winand's patch that I referenced upthread.
>>>
>>
>> here is a fix of some XMLTABLE mentioned issues.
>>
>
> this update allows cast boolean to numeric types from XPath expressions
>
Attached patch solves some cast issues mentioned by Chap. It solves issue
reported by Markus. I didn't use Markus's code, but it was inspiration for
me. I found native solution from libxml2.
Regards
Pavel
>
> Regards
>
> Pavel
>
>
>> Regards
>>
>> Pavel
>>
>>
>>
>>>
>>> --
>>> Álvaro Herrera https://www.2ndQuadrant.com/
>>> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
>>>
>>
diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index 37d85f71f3..8a95045b87 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -4427,6 +4427,35 @@ XmlTableFetchRow(TableFuncScanState *state)
#endif /* not USE_LIBXML */
}
+/*
+ * Copy XmlChar string to PostgreSQL memory. Ensure releasing of
+ * source xmllib string.
+ */
+static char *
+copy_and_safe_free_xmlchar(xmlChar *str)
+{
+ char *result;
+
+ if (str)
+ {
+ PG_TRY();
+ {
+ result = pstrdup((char *) str);
+ }
+ PG_CATCH();
+ {
+ xmlFree(str);
+ PG_RE_THROW();
+ }
+ PG_END_TRY();
+ xmlFree(str);
+ }
+ else
+ result = NULL;
+
+ return result;
+}
+
/*
* XmlTableGetValue
* Return the value for column number 'colnum' for the current row. If
@@ -4490,85 +4519,72 @@ XmlTableGetValue(TableFuncScanState *state, int colnum,
{
*isnull = true;
}
- else if (count == 1 && typid == XMLOID)
- {
- text *textstr;
-
- /* simple case, result is one value */
- textstr = xml_xmlnodetoxmltype(xpathobj->nodesetval->nodeTab[0],
- xtCxt->xmlerrcxt);
- cstr = text_to_cstring(textstr);
- }
- else if (count == 1)
+ else
{
- xmlChar *str;
- xmlNodePtr node;
-
- /*
- * Most nodes (elements and even attributes) store their data
- * in children nodes. If they don't have children nodes, it
- * means that they are empty (e.g. <element/>). Text nodes and
- * CDATA sections are an exception: they don't have children
- * but have content in the Text/CDATA node itself.
- */
- node = xpathobj->nodesetval->nodeTab[0];
- if (node->type != XML_CDATA_SECTION_NODE &&
- node->type != XML_TEXT_NODE)
- node = node->xmlChildrenNode;
-
- str = xmlNodeListGetString(xtCxt->doc, node, 1);
- if (str != NULL)
+ if (typid == XMLOID)
{
- PG_TRY();
- {
- cstr = pstrdup((char *) str);
- }
- PG_CATCH();
+ text *textstr;
+ StringInfoData str;
+ int i;
+
+ /* Concatenate serialized values */
+ initStringInfo(&str);
+ for (i = 0; i < count; i++)
{
- xmlFree(str);
- PG_RE_THROW();
+ textstr =
+ xml_xmlnodetoxmltype(xpathobj->nodesetval->nodeTab[i],
+ xtCxt->xmlerrcxt);
+
+ appendStringInfoText(&str, textstr);
}
- PG_END_TRY();
- xmlFree(str);
+ cstr = str.data;
}
else
{
- /* Ensure mapping of empty tags to PostgreSQL values. */
- cstr = "";
- }
- }
- else
- {
- StringInfoData str;
- int i;
-
- Assert(count > 1);
+ xmlChar *str;
- /*
- * When evaluating the XPath expression returns multiple
- * nodes, the result is the concatenation of them all. The
- * target type must be XML.
- */
- if (typid != XMLOID)
- ereport(ERROR,
- (errcode(ERRCODE_CARDINALITY_VIOLATION),
- errmsg("more than one value returned by column XPath expression")));
+ if (count > 1)
+ ereport(ERROR,
+ (errcode(ERRCODE_CARDINALITY_VIOLATION),
+ errmsg("more than one value returned by column XPath expression")));
- /* Concatenate serialized values */
- initStringInfo(&str);
- for (i = 0; i < count; i++)
- {
- appendStringInfoText(&str,
- xml_xmlnodetoxmltype(xpathobj->nodesetval->nodeTab[i],
- xtCxt->xmlerrcxt));
+ str = xmlXPathCastNodeSetToString(xpathobj->nodesetval);
+ if (str)
+ cstr = copy_and_safe_free_xmlchar(str);
+ else
+ /* empty element */
+ cstr = "";
}
- cstr = str.data;
}
}
else if (xpathobj->type == XPATH_STRING)
{
cstr = (char *) xpathobj->stringval;
}
+ else if (xpathobj->type == XPATH_BOOLEAN)
+ {
+ char typcategory;
+ bool typispreferred;
+ xmlChar *str;
+
+ /* Allow implicit casting from boolean to numbers */
+ get_type_category_preferred(typid, &typcategory, &typispreferred);
+
+ if (typcategory != TYPCATEGORY_NUMERIC)
+ str = xmlXPathCastBooleanToString(xpathobj->boolval);
+ else
+ str = xmlXPathCastNumberToString(
+ xmlXPathCastBooleanToNumber(xpathobj->boolval));
+
+ cstr = copy_and_safe_free_xmlchar(str);
+ }
+ else if (xpathobj->type == XPATH_NUMBER)
+ {
+ xmlChar *str;
+
+ str = xmlXPathCastNumberToString(xpathobj->floatval);
+ cstr = copy_and_safe_free_xmlchar(str);
+ }
else
elog(ERROR, "unexpected XPath object type %u", xpathobj->type);
diff --git a/src/test/regress/expected/xml.out b/src/test/regress/expected/xml.out
index 6e1f885112..7eb19d5a56 100644
--- a/src/test/regress/expected/xml.out
+++ b/src/test/regress/expected/xml.out
@@ -1210,9 +1210,9 @@ SELECT xmltable.* FROM xmldata, LATERAL xmltable('/ROWS/ROW[COUNTRY_NAME="Japan"
(2 rows)
SELECT * FROM xmltable('/root' passing '<root><element>a1a<!-- aaaa -->a2a<?aaaaa?> <!--z--> bbbb<x>xxx</x>cccc</element></root>' COLUMNS element text);
- element
--------------------
- a1aa2a bbbbcccc
+ element
+----------------------
+ a1aa2a bbbbxxxcccc
(1 row)
SELECT * FROM xmltable('/root' passing '<root><element>a1a<!-- aaaa -->a2a<?aaaaa?> <!--z--> bbbb<x>xxx</x>cccc</element></root>' COLUMNS element text PATH 'element/text()'); -- should fail
@@ -1493,3 +1493,16 @@ SELECT xmltable.* FROM xmltest2, LATERAL xmltable(('/d/r/' || lower(_path) || 'c
14
(4 rows)
+-- XPath result can be boolean or number too
+SELECT * FROM XMLTABLE('*' PASSING '<a>a</a>' COLUMNS a xml PATH '.', b text PATH '.', c text PATH '"hi"', d boolean PATH '. = "a"');
+ a | b | c | d
+----------+---+----+---
+ <a>a</a> | a | hi | t
+(1 row)
+
+SELECT * FROM XMLTABLE('*' PASSING '<a>a</a>' COLUMNS a xml PATH '.', b text PATH '.', c text PATH '"hi"', d integer PATH 'string-length(.)');
+ a | b | c | d
+----------+---+----+---
+ <a>a</a> | a | hi | 1
+(1 row)
+
diff --git a/src/test/regress/sql/xml.sql b/src/test/regress/sql/xml.sql
index 3b91b56d5a..1128ddb90f 100644
--- a/src/test/regress/sql/xml.sql
+++ b/src/test/regress/sql/xml.sql
@@ -595,3 +595,7 @@ INSERT INTO xmltest2 VALUES('<d><r><dc>2</dc></r></d>', 'D');
SELECT xmltable.* FROM xmltest2, LATERAL xmltable('/d/r' PASSING x COLUMNS a int PATH '' || lower(_path) || 'c');
SELECT xmltable.* FROM xmltest2, LATERAL xmltable(('/d/r/' || lower(_path) || 'c') PASSING x COLUMNS a int PATH '.');
SELECT xmltable.* FROM xmltest2, LATERAL xmltable(('/d/r/' || lower(_path) || 'c') PASSING x COLUMNS a int PATH 'x' DEFAULT ascii(_path) - 54);
+
+-- XPath result can be boolean or number too
+SELECT * FROM XMLTABLE('*' PASSING '<a>a</a>' COLUMNS a xml PATH '.', b text PATH '.', c text PATH '"hi"', d boolean PATH '. = "a"');
+SELECT * FROM XMLTABLE('*' PASSING '<a>a</a>' COLUMNS a xml PATH '.', b text PATH '.', c text PATH '"hi"', d integer PATH 'string-length(.)');
