Bug#26518 XPath and variables problem

Problem: XPath variables didn't work.
Fix: adding variables support,
both user-defined and sp local variables are now supported by XPath.

mysql-test/r/xml.result

@@ -884,3 +884,118 @@ test
 select ExtractValue('<a><self>test</self></a>', '/a/self');
 ExtractValue('<a><self>test</self></a>', '/a/self')
 test
+set @i=1;
+select ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]')
+b1
+set @i=2;
+select ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]')
+b2
+set @i=NULL;
+select ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]')
+
+CREATE PROCEDURE spxml(xml VARCHAR(128))
+BEGIN
+DECLARE c INT;
+DECLARE i INT DEFAULT 1;
+SET c= ExtractValue(xml,'count(/a/b)');
+SET @i= c;
+WHILE i <= c DO
+BEGIN
+SELECT i, @i, ExtractValue(xml,'/a/b[$i]'), ExtractValue(xml,'/a/b[$@i]');
+SET i= i + 1;
+SET @i= @i - 1;
+END;
+END WHILE;
+END|
+call spxml('<a><b>b1</b><b>b2</b><b>b3</b></a>');
+i	@i	ExtractValue(xml,'/a/b[$i]')	ExtractValue(xml,'/a/b[$@i]')
+1	3	b1	b3
+i	@i	ExtractValue(xml,'/a/b[$i]')	ExtractValue(xml,'/a/b[$@i]')
+2	2	b2	b2
+i	@i	ExtractValue(xml,'/a/b[$i]')	ExtractValue(xml,'/a/b[$@i]')
+3	1	b3	b1
+drop procedure spxml;
+Multiple matches, but no index specification
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b')
+b1 b2
+No matches
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/c');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/c')
+
+Index out of range
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[-1]');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[-1]')
+
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[10]');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[10]')
+
+With string-to-number conversion
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b["1"]');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b["1"]')
+b1
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b["1 and string"]');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b["1 and string"]')
+b1
+Warnings:
+Warning	1292	Truncated incorrect INTEGER value: '1 and string"]'
+Warning	1292	Truncated incorrect INTEGER value: '1 and string"]'
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b["string and 1"]');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b["string and 1"]')
+
+Warnings:
+Warning	1292	Truncated incorrect INTEGER value: 'string and 1"]'
+Warning	1292	Truncated incorrect INTEGER value: 'string and 1"]'
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b["string"]');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b["string"]')
+
+Warnings:
+Warning	1292	Truncated incorrect INTEGER value: 'string"]'
+Warning	1292	Truncated incorrect INTEGER value: 'string"]'
+String-to-number conversion from a user variable
+SET @i='1';
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]')
+b1
+SET @i='1 and string';
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]')
+b1
+SET @i='string and 1';
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]')
+
+SET @i='string';
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]');
+ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]')
+
+String-to-number conversion with a CHAR SP variable
+CREATE PROCEDURE spxml(xml VARCHAR(128), i CHAR(16))
+BEGIN
+SELECT ExtractValue(xml,'/a/b[$i]');
+END|
+CALL spxml('<a><b>b1</b><b>b2</b></a>', '1');
+ExtractValue(xml,'/a/b[$i]')
+b1
+CALL spxml('<a><b>b1</b><b>b2</b></a>', '1 and string');
+ExtractValue(xml,'/a/b[$i]')
+b1
+Warnings:
+Warning	1292	Truncated incorrect INTEGER value: '1 and string    '
+Warning	1292	Truncated incorrect INTEGER value: '1 and string    '
+CALL spxml('<a><b>b1</b><b>b2</b></a>', 'string and 1');
+ExtractValue(xml,'/a/b[$i]')
+
+Warnings:
+Warning	1292	Truncated incorrect INTEGER value: 'string and 1    '
+Warning	1292	Truncated incorrect INTEGER value: 'string and 1    '
+CALL spxml('<a><b>b1</b><b>b2</b></a>', 'string');
+ExtractValue(xml,'/a/b[$i]')
+
+Warnings:
+Warning	1292	Truncated incorrect INTEGER value: 'string          '
+Warning	1292	Truncated incorrect INTEGER value: 'string          '
+DROP PROCEDURE spxml;

mysql-test/t/xml.test

@@ -444,3 +444,75 @@ select ExtractValue('<a><parent>test</parent></a>', '/a/parent');
 select ExtractValue('<a><preceding>test</preceding></a>', '/a/preceding');
 select ExtractValue('<a><preceding-sibling>test</preceding-sibling></a>', '/a/preceding-sibling');
 select ExtractValue('<a><self>test</self></a>', '/a/self');
+
+#
+# Bug#26518 XPath and variables problem
+# Check with user defined variables
+#
+set @i=1;
+select ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]');
+set @i=2;
+select ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]');
+set @i=NULL;
+select ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]');
+
+#
+# Check variables in a stored procedure - both local and user variables
+# Make sure that SP and local variables with the same name work together.
+#
+DELIMITER |;
+CREATE PROCEDURE spxml(xml VARCHAR(128))
+BEGIN
+  DECLARE c INT;
+  DECLARE i INT DEFAULT 1;
+  SET c= ExtractValue(xml,'count(/a/b)');
+  SET @i= c;
+  WHILE i <= c DO
+    BEGIN
+      SELECT i, @i, ExtractValue(xml,'/a/b[$i]'), ExtractValue(xml,'/a/b[$@i]');
+      SET i= i + 1;
+      SET @i= @i - 1;
+    END;
+  END WHILE;
+END|
+DELIMITER ;|
+
+call spxml('<a><b>b1</b><b>b2</b><b>b3</b></a>');
+drop procedure spxml;
+
+#
+# Additional tests for bug#26518
+--echo Multiple matches, but no index specification
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b');
+--echo No matches
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/c');
+--echo Index out of range
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[-1]');
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[10]');
+--echo With string-to-number conversion
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b["1"]');
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b["1 and string"]');
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b["string and 1"]');
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b["string"]');
+--echo String-to-number conversion from a user variable
+SET @i='1';
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]');
+SET @i='1 and string';
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]');
+SET @i='string and 1';
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]');
+SET @i='string';
+SELECT ExtractValue('<a><b>b1</b><b>b2</b></a>','/a/b[$@i]');
+
+--echo String-to-number conversion with a CHAR SP variable
+DELIMITER |;
+CREATE PROCEDURE spxml(xml VARCHAR(128), i CHAR(16))
+BEGIN
+  SELECT ExtractValue(xml,'/a/b[$i]');
+END|
+DELIMITER ;|
+CALL spxml('<a><b>b1</b><b>b2</b></a>', '1');
+CALL spxml('<a><b>b1</b><b>b2</b></a>', '1 and string');
+CALL spxml('<a><b>b1</b><b>b2</b></a>', 'string and 1');
+CALL spxml('<a><b>b1</b><b>b2</b></a>', 'string');
+DROP PROCEDURE spxml;

sql/item_xmlfunc.cc

@@ -19,7 +19,7 @@
 
 #include "mysql_priv.h"
 #include "my_xml.h"
-
+#include "sp_pcontext.h"
 
 /*
   TODO: future development directions:
@@ -2412,21 +2412,78 @@ my_xpath_parse_QName(MY_XPATH *xpath)
 }
 
 
-/*
+/**
   Scan Variable reference
 
-  SYNOPSYS
+  @details Implements parsing of two syntax structures:
 
-    [36] VariableReference ::= '$' QName
-  RETURN
-    1 - success
-    0 - failure
+    1. Standard XPath syntax [36], for SP variables:
+
+      VariableReference ::= '$' QName     
+
+      Finds a SP variable with the given name.
+      If outside of a SP context, or variable with
+      the given name doesn't exists, then error is returned.
+
+    2. Non-standard syntax - MySQL extension for user variables:
+
+      VariableReference ::= '$' '@' QName
+
+    Item, corresponding to the variable, is returned
+    in xpath->item in both cases.
+
+  @param  xpath pointer to XPath structure
+
+  @return Operation status
+    @retval 1 Success
+    @retval 0 Failure
 */
+
 static int
 my_xpath_parse_VariableReference(MY_XPATH *xpath)
 {
-  return my_xpath_parse_term(xpath, MY_XPATH_LEX_DOLLAR) &&
-         my_xpath_parse_term(xpath, MY_XPATH_LEX_IDENT);
+  LEX_STRING name;
+  int user_var;
+  const char *dollar_pos;
+  if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_DOLLAR) ||
+      (!(dollar_pos= xpath->prevtok.beg)) ||
+      (!((user_var= my_xpath_parse_term(xpath, MY_XPATH_LEX_AT) &&
+         my_xpath_parse_term(xpath, MY_XPATH_LEX_IDENT))) &&
+       !my_xpath_parse_term(xpath, MY_XPATH_LEX_IDENT)))
+    return 0;
+
+  name.length= xpath->prevtok.end - xpath->prevtok.beg;
+  name.str= (char*) xpath->prevtok.beg;
+  
+  if (user_var)
+    xpath->item= new Item_func_get_user_var(name);
+  else
+  {
+    sp_variable_t *spv;
+    sp_pcontext *spc;
+    LEX *lex;
+    if ((lex= current_thd->lex) &&
+        (spc= lex->spcont) &&
+        (spv= spc->find_variable(&name)))
+    {
+      Item_splocal *splocal= new Item_splocal(name, spv->offset, spv->type, 0);
+#ifndef DBUG_OFF
+      if (splocal)
+        splocal->m_sp= lex->sphead;
+#endif
+      xpath->item= (Item*) splocal;
+    }
+    else
+    {
+      xpath->item= NULL;
+      DBUG_ASSERT(xpath->query.end > dollar_pos);
+      uint len= xpath->query.end - dollar_pos;
+      set_if_smaller(len, 32);
+      my_printf_error(ER_UNKNOWN_ERROR, "Unknown XPATH variable at: '%.*s'", 
+                      MYF(0), len, dollar_pos);
+    }
+  }
+  return xpath->item ? 1 : 0;
 }