Code review comment for lp:~sinha/drizzle/trunk-bug-621856

On Thu, 10 Mar 2011 21:57:07 -0000, Akash Sinha <email address hidden> wrote:
> --- drizzled/cursor.h 2011-03-07 12:31:41 +0000
> +++ drizzled/cursor.h 2011-03-10 21:44:21 +0000
> @@ -319,12 +319,12 @@
> virtual ha_rows estimate_rows_upper_bound()
> { return stats.records+EXTRA_RECORDS; }
>
> - virtual const char *index_type(uint32_t)
> + virtual const char *index_type()
> { assert(0); return "";}

It looks like index_type() is completely unused (apart from being implemented
in every storage engine) - so instead of just removing the parameter
(which shouldn't always be unused anyway) we should remove all the
implementations of it too.

> @@ -349,15 +349,15 @@
> const unsigned char * key,
> key_part_map keypart_map,
> enum ha_rkey_function find_flag);
> - virtual int index_next(unsigned char *) __attribute__ ((warn_unused_result))
> - { return HA_ERR_WRONG_COMMAND; }
> - virtual int index_prev(unsigned char *)
> - { return HA_ERR_WRONG_COMMAND; }
> - virtual int index_first(unsigned char *)
> - { return HA_ERR_WRONG_COMMAND; }
> - virtual int index_last(unsigned char *)
> - { return HA_ERR_WRONG_COMMAND; }
> - virtual int index_next_same(unsigned char *, const unsigned char *, uint32_t);
> + virtual int index_next() __attribute__ ((warn_unused_result))
> + { return HA_ERR_WRONG_COMMAND; }
> + virtual int index_prev()
> + { return HA_ERR_WRONG_COMMAND; }
> + virtual int index_first()
> + { return HA_ERR_WRONG_COMMAND; }
> + virtual int index_last()
> + { return HA_ERR_WRONG_COMMAND; }
> + virtual int index_next_same();

This is incorrect, the buffer being passed in is important and at least
*should* be used by classes implementing them.

> private:
> uint32_t calculate_key_len(uint32_t key_position, key_part_map keypart_map_arg);
> @@ -379,20 +379,20 @@
> bool eq_range, bool sorted);
> virtual int read_range_next();
> int compare_key(key_range *range);
> - virtual int rnd_next(unsigned char *)=0;
> - virtual int rnd_pos(unsigned char *, unsigned char *)=0;
> + virtual int rnd_next()=0;
> + virtual int rnd_pos()=0;

the rnd_pos() method is used and does use the parameters (just not in
the default implementation that does nothing), same with rnd_next() -
that is used.

> virtual int read_first_row(unsigned char *buf, uint32_t primary_key);
> - virtual int rnd_same(unsigned char *, uint32_t)
> + virtual int rnd_same()
> { return HA_ERR_WRONG_COMMAND; }
> - virtual ha_rows records_in_range(uint32_t, key_range *, key_range *)
> + virtual ha_rows records_in_range()
> { return (ha_rows) 10; }

also wrong, these parameters are used by all classes that implement it.

So most of this patch isn't quite right (especially around
Cursor). However, there are some unused bit sthat can work. I'd
recommend starting from scratch on a tree and doing these bits

I'd also be sure to when checking out any virtual function to check
everywhere that calls it as well as everywhere that implements it.

--
Stewart Smith