Clean-up: sharing duplicate code in Item_field::val_bool_result() and

Item_ref::val_bool_result().

sql/field.h

@@ -738,6 +738,7 @@ class Field: public Value_source
   { return store(ls->str, ls->length, cs); }
   virtual double val_real(void)=0;
   virtual longlong val_int(void)=0;
+  virtual bool val_bool(void)= 0;
   virtual my_decimal *val_decimal(my_decimal *);
   inline String *val_str(String *str) { return val_str(str, str); }
   /*
@@ -1491,6 +1492,7 @@ class Field_num :public Field {
   bool eq_def(Field *field);
   int store_decimal(const my_decimal *);
   my_decimal *val_decimal(my_decimal *);
+  bool val_bool() { return val_int() != 0; }
   uint is_equal(Create_field *new_field);
   uint row_pack_length() const { return pack_length(); }
   uint32 pack_length_from_metadata(uint field_metadata) {
@@ -1537,6 +1539,7 @@ class Field_str :public Field {
   uint32 max_display_length() { return field_length; }
   friend class Create_field;
   my_decimal *val_decimal(my_decimal *);
+  bool val_bool() { return val_real() != 0e0; }
   virtual bool str_needs_quotes() { return TRUE; }
   uint is_equal(Create_field *new_field);
   bool eq_cmp_as_binary() { return MY_TEST(flags & BINARY_FLAG); }
@@ -1609,6 +1612,7 @@ class Field_real :public Field_num {
   int  store_time_dec(MYSQL_TIME *ltime, uint dec);
   bool get_date(MYSQL_TIME *ltime, ulonglong fuzzydate);
   my_decimal *val_decimal(my_decimal *);
+  bool val_bool() { return val_real() != 0e0; }
   uint32 max_display_length() { return field_length; }
   uint size_of() const { return sizeof(*this); }
   Item *get_equal_const_item(THD *thd, const Context &ctx, Item *const_item);
@@ -1684,6 +1688,12 @@ class Field_new_decimal :public Field_num {
   my_decimal *val_decimal(my_decimal *);
   String *val_str(String*, String *);
   bool get_date(MYSQL_TIME *ltime, ulonglong fuzzydate);
+  bool val_bool()
+  {
+    my_decimal decimal_value;
+    my_decimal *val= val_decimal(&decimal_value);
+    return val ? !my_decimal_is_zero(val) : 0;
+  }
   int cmp(const uchar *, const uchar *);
   void sort_string(uchar *buff, uint length);
   bool zero_pack() const { return 0; }
@@ -2009,6 +2019,7 @@ class Field_null :public Field_str {
   int reset(void)	  { return 0; }
   double val_real(void)		{ return 0.0;}
   longlong val_int(void)	{ return 0;}
+  bool val_bool(void) { return false; }
   my_decimal *val_decimal(my_decimal *) { return 0; }
   String *val_str(String *value,String *value2)
   { value2->length(0); return value2;}
@@ -2054,6 +2065,7 @@ class Field_temporal: public Field {
   CHARSET_INFO *sort_charset(void) const { return &my_charset_bin; }
   bool binary() const { return true; }
   enum Item_result cmp_type () const { return TIME_RESULT; }
+  bool val_bool() { return val_real() != 0e0; }
   uint is_equal(Create_field *new_field);
   bool eq_def(Field *field)
   {
@@ -3267,6 +3279,7 @@ class Field_bit :public Field {
   String *val_str(String*, String *);
   virtual bool str_needs_quotes() { return TRUE; }
   my_decimal *val_decimal(my_decimal *);
+  bool val_bool() { return val_int() != 0; }
   int cmp(const uchar *a, const uchar *b)
   {
     DBUG_ASSERT(ptr == a || ptr == b);

sql/item.cc

@@ -2560,27 +2560,8 @@ my_decimal *Item_field::val_decimal_result(my_decimal *decimal_value)
 bool Item_field::val_bool_result()
 {
   if ((null_value= result_field->is_null()))
-    return FALSE;
-  switch (result_field->result_type()) {
-  case INT_RESULT:
-    return result_field->val_int() != 0;
-  case DECIMAL_RESULT:
-  {
-    my_decimal decimal_value;
-    my_decimal *val= result_field->val_decimal(&decimal_value);
-    if (val)
-      return !my_decimal_is_zero(val);
-    return 0;
-  }
-  case REAL_RESULT:
-  case STRING_RESULT:
-    return result_field->val_real() != 0.0;
-  case ROW_RESULT:
-  case TIME_RESULT:
-    DBUG_ASSERT(0);
-    return 0;                                   // Shut up compiler
-  }
-  return 0;
+    return false;
+  return result_field->val_bool();
 }
 
 
@@ -7204,25 +7185,8 @@ bool Item_ref::val_bool_result()
   if (result_field)
   {
     if ((null_value= result_field->is_null()))
-      return 0;
-    switch (result_field->result_type()) {
-    case INT_RESULT:
-      return result_field->val_int() != 0;
-    case DECIMAL_RESULT:
-    {
-      my_decimal decimal_value;
-      my_decimal *val= result_field->val_decimal(&decimal_value);
-      if (val)
-        return !my_decimal_is_zero(val);
-      return 0;
-    }
-    case REAL_RESULT:
-    case STRING_RESULT:
-      return result_field->val_real() != 0.0;
-    case ROW_RESULT:
-    case TIME_RESULT:
-      DBUG_ASSERT(0);
-    }
+      return false;
+    return result_field->val_bool();
   }
   return val_bool();
 }