MDEV-11298 Split Item_func_hex::val_str_ascii() into virtual methods in Type_handler

6 files changed, 162 insertions, 47 deletions

diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc
index b7efa60c520..81557787c36 100644
--- a/sql/item_strfunc.cc
+++ b/sql/item_strfunc.cc
@@ -3634,53 +3634,41 @@ void Item_func_weight_string::print(String *str, enum_query_type query_type)
 }
 
 
-String *Item_func_hex::val_str_ascii(String *str)
+String *Item_func_hex::val_str_ascii_from_val_real(String *str)
 {
-  String *res;
-  DBUG_ASSERT(fixed == 1);
-  if (args[0]->result_type() != STRING_RESULT)
-  {
-    ulonglong dec;
-    char ans[65],*ptr;
-    /* Return hex of unsigned longlong value */
-    if (args[0]->result_type() == REAL_RESULT ||
-        args[0]->result_type() == DECIMAL_RESULT)
-    {
-      double val= args[0]->val_real();
-      if ((val <= (double) LONGLONG_MIN) || 
-          (val >= (double) (ulonglong) ULONGLONG_MAX))
-        dec=  ~(longlong) 0;
-      else
-        dec= (ulonglong) (val + (val > 0 ? 0.5 : -0.5));
-    }
-    else
-      dec= (ulonglong) args[0]->val_int();
+  ulonglong dec;
+  double val= args[0]->val_real();
+  if ((null_value= args[0]->null_value))
+    return 0;
+  if ((val <= (double) LONGLONG_MIN) ||
+      (val >= (double) (ulonglong) ULONGLONG_MAX))
+    dec= ~(longlong) 0;
+  else
+    dec= (ulonglong) (val + (val > 0 ? 0.5 : -0.5));
+  return str->set_hex(dec) ? make_empty_result() : str;
+}
 
-    if ((null_value= args[0]->null_value))
-      return 0;
-    
-    if (!(ptr= longlong2str(dec, ans, 16)) ||
-        str->copy(ans,(uint32) (ptr - ans),
-        &my_charset_numeric))
-      return make_empty_result();		// End of memory
-    return str;
-  }
 
-  /* Convert given string to a hex string, character by character */
-  res= args[0]->val_str(str);
-  if (!res || tmp_value.alloc(res->length()*2+1))
-  {
-    null_value=1;
-    return 0;
-  }
-  null_value=0;
-  tmp_value.length(res->length()*2);
-  tmp_value.set_charset(&my_charset_latin1);
+String *Item_func_hex::val_str_ascii_from_val_str(String *str)
+{
+  DBUG_ASSERT(&tmp_value != str);
+  String *res= args[0]->val_str(&tmp_value);
+  DBUG_ASSERT(res != str);
+  if ((null_value= (res == NULL)))
+    return NULL;
+  return str->set_hex(res->ptr(), res->length()) ? make_empty_result() : str;
+}
 
-  octet2hex((char*) tmp_value.ptr(), res->ptr(), res->length());
-  return &tmp_value;
+
+String *Item_func_hex::val_str_ascii_from_val_int(String *str)
+{
+  ulonglong dec= (ulonglong) args[0]->val_int();
+  if ((null_value= args[0]->null_value))
+    return 0;
+  return str->set_hex(dec) ? make_empty_result() : str;
 }
 
+
   /** Convert given hex string to a binary string. */
 
 String *Item_func_unhex::val_str(String *str)
diff --git a/sql/item_strfunc.h b/sql/item_strfunc.h
index be23f45c286..50258c84daa 100644
--- a/sql/item_strfunc.h
+++ b/sql/item_strfunc.h
@@ -913,17 +913,33 @@ public:
 
 class Item_func_hex :public Item_str_ascii_func
 {
+protected:
   String tmp_value;
+  /*
+    Calling arg[0]->type_handler() can be expensive on every row.
+    It's a virtual method, and in case if args[0] is a complex Item,
+    its type_handler() can call more virtual methods.
+    So let's cache it during fix_length_and_dec().
+  */
+  const Type_handler *m_arg0_type_handler;
 public:
   Item_func_hex(THD *thd, Item *a):
-    Item_str_ascii_func(thd, a) {}
+    Item_str_ascii_func(thd, a), m_arg0_type_handler(NULL) {}
   const char *func_name() const { return "hex"; }
-  String *val_str_ascii(String *);
+  String *val_str_ascii_from_val_int(String *str);
+  String *val_str_ascii_from_val_real(String *str);
+  String *val_str_ascii_from_val_str(String *str);
+  String *val_str_ascii(String *str)
+  {
+    DBUG_ASSERT(fixed);
+    return m_arg0_type_handler->Item_func_hex_val_str_ascii(this, str);
+  }
   void fix_length_and_dec()
   {
     collation.set(default_charset());
     decimals=0;
     fix_char_length(args[0]->max_length * 2);
+    m_arg0_type_handler= args[0]->type_handler();
   }
   Item *get_copy(THD *thd, MEM_ROOT *mem_root)
   { return get_item_copy<Item_func_hex>(thd, mem_root, this); }
diff --git a/sql/sql_string.cc b/sql/sql_string.cc
index 62473e082c3..b12f0332035 100644
--- a/sql/sql_string.cc
+++ b/sql/sql_string.cc
@@ -130,6 +130,61 @@ bool String::set_int(longlong num, bool unsigned_flag, CHARSET_INFO *cs)
   return FALSE;
 }
 
+
+// Convert a number into its HEX representation
+bool String::set_hex(ulonglong num)
+{
+  char *n_end;
+  if (alloc(65) || !(n_end= longlong2str(num, Ptr, 16)))
+    return true;
+  length((uint32) (n_end - Ptr));
+  set_charset(&my_charset_latin1);
+  return false;
+}
+
+
+/**
+  Append a hex representation of the byte "value" into "to".
+  Note:
+    "to" is incremented for the caller by two bytes. It's passed by reference!
+    So it resembles a macros, hence capital letters in the name.
+*/
+static inline void APPEND_HEX(char *&to, uchar value)
+{
+  *to++= _dig_vec_upper[((uchar) value) >> 4];
+  *to++= _dig_vec_upper[((uchar) value) & 0x0F];
+}
+
+
+void String::qs_append_hex(const char *str, uint32 len)
+{
+  const char *str_end= str + len;
+  for (char *to= Ptr + str_length ; str < str_end; str++)
+    APPEND_HEX(to, (uchar) *str);
+  str_length+= len * 2;
+}
+
+
+// Convert a string to its HEX representation
+bool String::set_hex(const char *str, uint32 len)
+{
+  /*
+    Safety: cut the source string if "len" is too large.
+    Note, alloc() can allocate some more space than requested, due to:
+    - ALIGN_SIZE
+    - one extra byte for a null terminator
+    So cut the source string to 0x7FFFFFF0 rather than 0x7FFFFFFE.
+  */
+  set_if_smaller(len, 0x7FFFFFF0);
+  if (alloc(len * 2))
+    return true;
+  length(0);
+  qs_append_hex(str, len);
+  set_charset(&my_charset_latin1);
+  return false;
+}
+
+
 bool String::set_real(double num,uint decimals, CHARSET_INFO *cs)
 {
   char buff[FLOATING_POINT_BUFFER];
@@ -960,8 +1015,7 @@ my_copy_with_hex_escaping(CHARSET_INFO *cs,
         break; /* purecov: inspected */
       *dst++= '\\';
       *dst++= 'x';
-      *dst++= _dig_vec_upper[((unsigned char) *src) >> 4];
-      *dst++= _dig_vec_upper[((unsigned char) *src) & 15];
+      APPEND_HEX(dst, (uchar) *src);
       src++;
       dstlen-= 4;
     }
@@ -1146,8 +1200,7 @@ uint convert_to_printable(char *to, size_t to_len,
         break;
       *t++= '\\';
       *t++= 'x';
-      *t++= _dig_vec_upper[((unsigned char) *f) >> 4];
-      *t++= _dig_vec_upper[((unsigned char) *f) & 0x0F];
+      APPEND_HEX(t, *f);
     }
     if (t_end - t >= 3) // '...'
       dots= t;
diff --git a/sql/sql_string.h b/sql/sql_string.h
index 4b70675dca4..8062e2d465d 100644
--- a/sql/sql_string.h
+++ b/sql/sql_string.h
@@ -293,6 +293,9 @@ public:
   bool set(ulonglong num, CHARSET_INFO *cs) { return set_int((longlong)num, true, cs); }
   bool set_real(double num,uint decimals, CHARSET_INFO *cs);
 
+  bool set_hex(ulonglong num);
+  bool set_hex(const char *str, uint32 len);
+
   /* Take over handling of buffer from some other object */
   void reset(char *ptr_arg, uint32 length_arg, uint32 alloced_length_arg,
              CHARSET_INFO *cs)
@@ -567,6 +570,7 @@ public:
     qs_append(str, (uint32)strlen(str));
   }
   void qs_append(const char *str, uint32 len);
+  void qs_append_hex(const char *str, uint32 len);
   void qs_append(double d);
   void qs_append(double *d);
   inline void qs_append(const char c)
diff --git a/sql/sql_type.cc b/sql/sql_type.cc
index 12fd73d4336..87465952272 100644
--- a/sql/sql_type.cc
+++ b/sql/sql_type.cc
@@ -859,3 +859,44 @@ bool Type_handler_temporal_result::
 }
 
 /*************************************************************************/
+
+String *
+Type_handler_real_result::Item_func_hex_val_str_ascii(Item_func_hex *item,
+                                                      String *str) const
+{
+  return item->val_str_ascii_from_val_real(str);
+}
+
+
+String *
+Type_handler_decimal_result::Item_func_hex_val_str_ascii(Item_func_hex *item,
+                                                         String *str) const
+{
+  return item->val_str_ascii_from_val_real(str);
+}
+
+
+String *
+Type_handler_int_result::Item_func_hex_val_str_ascii(Item_func_hex *item,
+                                                     String *str) const
+{
+  return item->val_str_ascii_from_val_int(str);
+}
+
+
+String *
+Type_handler_temporal_result::Item_func_hex_val_str_ascii(Item_func_hex *item,
+                                                          String *str) const
+{
+  return item->val_str_ascii_from_val_str(str);
+}
+
+
+String *
+Type_handler_string_result::Item_func_hex_val_str_ascii(Item_func_hex *item,
+                                                        String *str) const
+{
+  return item->val_str_ascii_from_val_str(str);
+}
+
+/*************************************************************************/
diff --git a/sql/sql_type.h b/sql/sql_type.h
index ef85f3d8d75..92dee611acb 100644
--- a/sql/sql_type.h
+++ b/sql/sql_type.h
@@ -27,6 +27,7 @@ class Field;
 class Item;
 class Item_cache;
 class Item_sum_hybrid;
+class Item_func_hex;
 class Type_std_attributes;
 class Sort_param;
 class Arg_comparator;
@@ -291,6 +292,8 @@ public:
   virtual Item_cache *Item_get_cache(THD *thd, const Item *item) const= 0;
   virtual bool set_comparator_func(Arg_comparator *cmp) const= 0;
   virtual bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *) const= 0;
+  virtual String *Item_func_hex_val_str_ascii(Item_func_hex *item,
+                                              String *str) const= 0;
 };
 
 
@@ -349,6 +352,11 @@ public:
     DBUG_ASSERT(0);
     return true;
   }
+  String *Item_func_hex_val_str_ascii(Item_func_hex *item, String *str) const
+  {
+    DBUG_ASSERT(0);
+    return NULL;
+  }
 };
 
 
@@ -383,6 +391,7 @@ public:
   Item_cache *Item_get_cache(THD *thd, const Item *item) const;
   bool set_comparator_func(Arg_comparator *cmp) const;
   bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const;
+  String *Item_func_hex_val_str_ascii(Item_func_hex *item, String *str) const;
 };
 
 
@@ -402,6 +411,7 @@ public:
   Item_cache *Item_get_cache(THD *thd, const Item *item) const;
   bool set_comparator_func(Arg_comparator *cmp) const;
   bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const;
+  String *Item_func_hex_val_str_ascii(Item_func_hex *item, String *str) const;
 };
 
 
@@ -421,6 +431,7 @@ public:
   Item_cache *Item_get_cache(THD *thd, const Item *item) const;
   bool set_comparator_func(Arg_comparator *cmp) const;
   bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const;
+  String *Item_func_hex_val_str_ascii(Item_func_hex *item, String *str) const;
 };
 
 
@@ -438,6 +449,7 @@ public:
   Item_cache *Item_get_cache(THD *thd, const Item *item) const;
   bool set_comparator_func(Arg_comparator *cmp) const;
   bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const;
+  String *Item_func_hex_val_str_ascii(Item_func_hex *item, String *str) const;
 };
 
 
@@ -459,6 +471,7 @@ public:
   Item_cache *Item_get_cache(THD *thd, const Item *item) const;
   bool set_comparator_func(Arg_comparator *cmp) const;
   bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const;
+  String *Item_func_hex_val_str_ascii(Item_func_hex *item, String *str) const;
 };