diff options
Diffstat (limited to 'sql')
| -rw-r--r-- | sql/item_cmpfunc.cc | 4 | ||||
| -rw-r--r-- | sql/sql_string.h | 10 |
2 files changed, 14 insertions, 0 deletions
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc index c5e6d520ab7..46ef3281dd1 100644 --- a/sql/item_cmpfunc.cc +++ b/sql/item_cmpfunc.cc @@ -1503,7 +1503,11 @@ void in_string::set(uint pos,Item *item) String *str=((String*) base)+pos; String *res=item->val_str(str); if (res && res != str) + { + if (res->uses_buffer_owned_by(str)) + res->copy(); *str= *res; + } if (!str->charset()) { CHARSET_INFO *cs; diff --git a/sql/sql_string.h b/sql/sql_string.h index a8fb9574c0b..9136dddbbf2 100644 --- a/sql/sql_string.h +++ b/sql/sql_string.h @@ -182,6 +182,11 @@ public: { if (&s != this) { + /* + It is forbidden to do assignments like + some_string = substring_of_that_string + */ + DBUG_ASSERT(!s.uses_buffer_owned_by(this)); free(); Ptr=s.Ptr ; str_length=s.str_length ; Alloced_length=s.Alloced_length; alloced=0; @@ -313,4 +318,9 @@ public: /* Swap two string objects. Efficient way to exchange data without memcpy. */ void swap(String &s); + + inline bool uses_buffer_owned_by(const String *s) const + { + return (s->alloced && Ptr >= s->Ptr && Ptr < s->Ptr + s->str_length); + } }; |