MDEV-17995 INET6_NTOA(ucs2_input) erroneously returns NULL

mysql-test/main/ctype_ucs.result

@@ -6383,3 +6383,15 @@ DEALLOCATE PREPARE stmt;
 #
 # End of 10.2 tests
 #
+#
+# Start of 10.4 tests
+#
+#
+# MDEV-17995 INET6_NTOA(ucs2_input) erroneously returns NULL
+#
+SELECT HEX(INET6_ATON('1::1')), HEX(INET6_ATON(CONVERT('1::1' USING ucs2)));
+HEX(INET6_ATON('1::1'))	HEX(INET6_ATON(CONVERT('1::1' USING ucs2)))
+00010000000000000000000000000001	00010000000000000000000000000001
+#
+# End of 10.4 tests
+#

mysql-test/main/ctype_ucs.test

@@ -1094,3 +1094,18 @@ DEALLOCATE PREPARE stmt;
 --echo #
 --echo # End of 10.2 tests
 --echo #
+
+--echo #
+--echo # Start of 10.4 tests
+--echo #
+
+--echo #
+--echo # MDEV-17995 INET6_NTOA(ucs2_input) erroneously returns NULL
+--echo #
+
+SELECT HEX(INET6_ATON('1::1')), HEX(INET6_ATON(CONVERT('1::1' USING ucs2)));
+
+
+--echo #
+--echo # End of 10.4 tests
+--echo #

sql/item_inetfunc.cc

@@ -162,41 +162,6 @@ longlong Item_func_inet_bool_base::val_int()
   return calc_value(arg_str) ? 1 : 0;
 }
 
-///////////////////////////////////////////////////////////////////////////
-
-/**
-  Check the function argument, handle errors properly.
-
-  @param [out] buffer Buffer for string operations.
-
-  @return The function value.
-*/
-
-String *Item_func_inet_str_base::val_str_ascii(String *buffer)
-{
-  DBUG_ASSERT(fixed);
-
- // String argument expected
-  if (unlikely(args[0]->result_type() != STRING_RESULT))
-  {
-    null_value= true;
-    return NULL;
-  }
-
-  StringBuffer<STRING_BUFFER_USUAL_SIZE> tmp;
-  String *arg_str= args[0]->val_str(&tmp);
-  if (unlikely(!arg_str))
-  {
-    // Out-of memory happened. error has been reported.
-    // Or: the underlying field is NULL
-    null_value= true;
-    return NULL;
-  }
-
-  null_value= !calc_value(arg_str, buffer);
-
-  return unlikely(null_value) ? NULL : buffer;
-}
 
 ///////////////////////////////////////////////////////////////////////////
 
@@ -673,6 +638,23 @@ static void ipv6_to_str(const in6_addr *ipv6, char *str)
 
 ///////////////////////////////////////////////////////////////////////////
 
+String *Item_func_inet6_aton::val_str(String *buffer)
+{
+  DBUG_ASSERT(fixed);
+
+  // String argument expected
+  if (unlikely(args[0]->result_type() != STRING_RESULT))
+  {
+    null_value= true;
+    return NULL;
+  }
+
+  Ascii_ptr_and_buffer<STRING_BUFFER_USUAL_SIZE> tmp(args[0]);
+  null_value= tmp.is_null() || !calc_value(tmp.string(), buffer);
+  return unlikely(null_value) ? NULL : buffer;
+}
+
+
 /**
   Converts IP-address-string to IP-address-data.
 
@@ -713,6 +695,32 @@ bool Item_func_inet6_aton::calc_value(const String *arg, String *buffer)
 
 ///////////////////////////////////////////////////////////////////////////
 
+/**
+  Check the function argument, handle errors properly.
+
+  @param [out] buffer Buffer for string operations.
+
+  @return The function value.
+*/
+
+String *Item_func_inet6_ntoa::val_str_ascii(String *buffer)
+{
+  DBUG_ASSERT(fixed);
+
+  // Binary string argument expected
+  if (unlikely(args[0]->result_type() != STRING_RESULT ||
+               args[0]->collation.collation != &my_charset_bin))
+  {
+    null_value= true;
+    return NULL;
+  }
+
+  String_ptr_and_buffer<STRING_BUFFER_USUAL_SIZE> tmp(args[0]);
+  null_value= tmp.is_null() || !calc_value(tmp.string(), buffer);
+  return unlikely(null_value) ? NULL : buffer;
+}
+
+
 /**
   Converts IP-address-data to IP-address-string.
 
@@ -724,11 +732,8 @@ bool Item_func_inet6_aton::calc_value(const String *arg, String *buffer)
   @retval true  The string has been converted sucessfully.
 */
 
-bool Item_func_inet6_ntoa::calc_value(const String *arg, String *buffer)
+bool Item_func_inet6_ntoa::calc_value(const Binary_string *arg, String *buffer)
 {
-  if (arg->charset() != &my_charset_bin)
-    return false;
-
   if ((int) arg->length() == IN_ADDR_SIZE)
   {
     char str[INET_ADDRSTRLEN];

sql/item_inetfunc.h

@@ -91,35 +91,15 @@ class Item_func_inet_bool_base : public Item_bool_func
 };
 
 
-/*************************************************************************
-  Item_func_inet_str_base implements common code for INET6/IP-related
-  functions returning string value.
-*************************************************************************/
-
-class Item_func_inet_str_base : public Item_str_ascii_func
-{
-public:
-  inline Item_func_inet_str_base(THD *thd, Item *arg):
-    Item_str_ascii_func(thd, arg)
-  { }
-
-public:
-  virtual String *val_str_ascii(String *buffer);
-
-protected:
-  virtual bool calc_value(const String *arg, String *buffer) = 0;
-};
-
-
 /*************************************************************************
   Item_func_inet6_aton implements INET6_ATON() SQL-function.
 *************************************************************************/
 
-class Item_func_inet6_aton : public Item_func_inet_str_base
+class Item_func_inet6_aton : public Item_str_func
 {
 public:
   inline Item_func_inet6_aton(THD *thd, Item *ip_addr):
-    Item_func_inet_str_base(thd, ip_addr)
+    Item_str_func(thd, ip_addr)
   { }
 
 public:
@@ -136,8 +116,10 @@ class Item_func_inet6_aton : public Item_func_inet_str_base
   Item *get_copy(THD *thd)
   { return get_item_copy<Item_func_inet6_aton>(thd, this); }
 
+  String *val_str(String *to);
+
 protected:
-  virtual bool calc_value(const String *arg, String *buffer);
+  bool calc_value(const String *arg, String *buffer);
 };
 
 
@@ -145,11 +127,11 @@ class Item_func_inet6_aton : public Item_func_inet_str_base
   Item_func_inet6_ntoa implements INET6_NTOA() SQL-function.
 *************************************************************************/
 
-class Item_func_inet6_ntoa : public Item_func_inet_str_base
+class Item_func_inet6_ntoa : public Item_str_ascii_func
 {
 public:
   inline Item_func_inet6_ntoa(THD *thd, Item *ip_addr):
-    Item_func_inet_str_base(thd, ip_addr)
+    Item_str_ascii_func(thd, ip_addr)
   { }
 
 public:
@@ -168,11 +150,12 @@ class Item_func_inet6_ntoa : public Item_func_inet_str_base
     maybe_null= 1;
     return FALSE;
   }
+  String *val_str_ascii(String *to);
   Item *get_copy(THD *thd)
   { return get_item_copy<Item_func_inet6_ntoa>(thd, this); }
 
 protected:
-  virtual bool calc_value(const String *arg, String *buffer);
+  bool calc_value(const Binary_string *arg, String *buffer);
 };
 
 

sql/sql_type.cc

@@ -134,6 +134,15 @@ bool Type_handler_data::init()
 Type_handler_data *type_handler_data= NULL;
 
 
+String_ptr::String_ptr(Item *item, String *buffer)
+ :m_string_ptr(item->val_str(buffer))
+{ }
+
+
+Ascii_ptr::Ascii_ptr(Item *item, String *buffer)
+ :String_ptr(item->val_str_ascii(buffer))
+{ }
+
 
 void VDec::set(Item *item)
 {

sql/sql_type.h

@@ -110,6 +110,58 @@ class NativeBuffer: public Native
 };
 
 
+class String_ptr
+{
+protected:
+  String *m_string_ptr;
+public:
+  String_ptr(String *str)
+   :m_string_ptr(str)
+  { }
+  String_ptr(Item *item, String *buffer);
+  const String *string() const { return m_string_ptr; }
+  const char *ptr() const
+  {
+    DBUG_ASSERT(m_string_ptr);
+    return m_string_ptr->ptr();
+  }
+  uint32 length() const
+  {
+    DBUG_ASSERT(m_string_ptr);
+    return m_string_ptr->length();
+  }
+  bool is_null() const { return m_string_ptr == NULL; }
+};
+
+
+class Ascii_ptr: public String_ptr
+{
+public:
+  Ascii_ptr(Item *item, String *buffer);
+};
+
+
+template<size_t buff_sz>
+class String_ptr_and_buffer: public StringBuffer<buff_sz>,
+                             public String_ptr
+{
+public:
+  String_ptr_and_buffer(Item *item)
+   :String_ptr(item, this)
+  { }
+};
+
+
+template<size_t buff_sz>
+class Ascii_ptr_and_buffer: public StringBuffer<buff_sz>,
+                            public Ascii_ptr
+{
+public:
+  Ascii_ptr_and_buffer(Item *item)
+   :Ascii_ptr(item, this)
+  { }
+};
+
 
 class Dec_ptr
 {