Bug# 25998635: Client does not escape the USE statement

When there are quotes in the USE statement, the mysql client does
not correctly escape them.

The USE statement is processed line by line from the client's parser,
and cannot handle multi-line commands as the server.

The fix is to escape the USE parameters whenever quotes are used.

client/mysql.cc

@@ -3386,7 +3386,7 @@ print_table_data(MYSQL_RES *result)
       length=4;					// Room for "NULL"
     if (opt_binhex && is_binary_field(field))
       length= 2 + length * 2;
-    field->max_length=length;
+    field->max_length=(ulong) length;
     separator.fill(separator.length()+length+2,'-');
     separator.append('+');
   }
@@ -3453,7 +3453,7 @@ print_table_data(MYSQL_RES *result)
        many extra padding-characters we should send with the printing function.
       */
       visible_length= charset_info->cset->numcells(charset_info, buffer, buffer + data_length);
-      extra_padding= data_length - visible_length;
+      extra_padding= (uint) (data_length - visible_length);
 
       if (opt_binhex && is_binary_field(field))
         print_as_hex(PAGER, cur[off], lengths[off], field_max_length);
@@ -4232,10 +4232,9 @@ com_use(String *buffer __attribute__((unused)), char *line)
   bzero(buff, sizeof(buff));
 
   /*
-    In case number of quotes exceed 2, we try to get
-    the normalized db name.
+    In case of quotes used, try to get the normalized db name.
   */
-  if (get_quote_count(line) > 2)
+  if (get_quote_count(line) > 0)
   {
     if (normalize_dbname(line, buff, sizeof(buff)))
       return put_error(&mysql);
@@ -4453,11 +4452,13 @@ char *get_arg(char *line, my_bool get_next_arg)
 static int
 get_quote_count(const char *line)
 {
-  int quote_count;
-  const char *ptr= line;
+  int quote_count= 0;
+  const char *quote= line;
 
-  for(quote_count= 0; ptr ++ && *ptr; ptr= strpbrk(ptr, "\"\'`"))
-    quote_count ++;
+  while ((quote= strpbrk(quote, "'`\"")) != NULL) {
+    quote_count++;
+    quote++;
+  }
 
   return quote_count;
 }