WL#3817: Simplify string / memory area types and make things more consistent (first part)

The following type conversions was done:

- Changed byte to uchar
- Changed gptr to uchar*
- Change my_string to char *
- Change my_size_t to size_t
- Change size_s to size_t

Removed declaration of byte, gptr, my_string, my_size_t and size_s. 

Following function parameter changes was done:
- All string functions in mysys/strings was changed to use size_t
  instead of uint for string lengths.
- All read()/write() functions changed to use size_t (including vio).
- All protocoll functions changed to use size_t instead of uint
- Functions that used a pointer to a string length was changed to use size_t*
- Changed malloc(), free() and related functions from using gptr to use void *
  as this requires fewer casts in the code and is more in line with how the
  standard functions work.
- Added extra length argument to dirname_part() to return the length of the
  created string.
- Changed (at least) following functions to take uchar* as argument:
  - db_dump()
  - my_net_write()
  - net_write_command()
  - net_store_data()
  - DBUG_DUMP()
  - decimal2bin() & bin2decimal()
- Changed my_compress() and my_uncompress() to use size_t. Changed one
  argument to my_uncompress() from a pointer to a value as we only return
  one value (makes function easier to use).
- Changed type of 'pack_data' argument to packfrm() to avoid casts.
- Changed in readfrm() and writefrom(), ha_discover and handler::discover()
  the type for argument 'frmdata' to uchar** to avoid casts.
- Changed most Field functions to use uchar* instead of char* (reduced a lot of
  casts).
- Changed field->val_xxx(xxx, new_ptr) to take const pointers.

Other changes:
- Removed a lot of not needed casts
- Added a few new cast required by other changes
- Added some cast to my_multi_malloc() arguments for safety (as string lengths
  needs to be uint, not size_t).
- Fixed all calls to hash-get-key functions to use size_t*. (Needed to be done
  explicitely as this conflict was often hided by casting the function to
  hash_get_key).
- Changed some buffers to memory regions to uchar* to avoid casts.
- Changed some string lengths from uint to size_t.
- Changed field->ptr to be uchar* instead of char*. This allowed us to
  get rid of a lot of casts.
- Some changes from true -> TRUE, false -> FALSE, unsigned char -> uchar
- Include zlib.h in some files as we needed declaration of crc32()
- Changed MY_FILE_ERROR to be (size_t) -1.
- Changed many variables to hold the result of my_read() / my_write() to be
  size_t. This was needed to properly detect errors (which are
  returned as (size_t) -1).
- Removed some very old VMS code
- Changed packfrm()/unpackfrm() to not be depending on uint size
  (portability fix)
- Removed windows specific code to restore cursor position as this
  causes slowdown on windows and we should not mix read() and pread()
  calls anyway as this is not thread safe. Updated function comment to
  reflect this. Changed function that depended on original behavior of
  my_pwrite() to itself restore the cursor position (one such case).
- Added some missing checking of return value of malloc().
- Changed definition of MOD_PAD_CHAR_TO_FULL_LENGTH to avoid 'long' overflow.
- Changed type of table_def::m_size from my_size_t to ulong to reflect that
  m_size is the number of elements in the array, not a string/memory
  length.
- Moved THD::max_row_length() to table.cc (as it's not depending on THD).
  Inlined max_row_length_blob() into this function.
- More function comments
- Fixed some compiler warnings when compiled without partitions.
- Removed setting of LEX_STRING() arguments in declaration (portability fix).
- Some trivial indentation/variable name changes.
- Some trivial code simplifications:
  - Replaced some calls to alloc_root + memcpy to use
    strmake_root()/strdup_root().
  - Changed some calls from memdup() to strmake() (Safety fix)
  - Simpler loops in client-simple.c

include/violite.h

@@ -51,8 +51,8 @@ Vio* vio_new_win32shared_memory(NET *net,HANDLE handle_file_map,
                                 HANDLE event_client_wrote,
                                 HANDLE event_client_read,
                                 HANDLE event_conn_closed);
-int vio_read_pipe(Vio *vio, gptr buf, int size);
-int vio_write_pipe(Vio *vio, const gptr buf, int size);
+size_t vio_read_pipe(Vio *vio, uchar * buf, size_t size);
+size_t vio_write_pipe(Vio *vio, const uchar * buf, size_t size);
 int vio_close_pipe(Vio * vio);
 #else
 #define HANDLE void *
@@ -62,9 +62,9 @@ void	vio_delete(Vio* vio);
 int	vio_close(Vio* vio);
 void    vio_reset(Vio* vio, enum enum_vio_type type,
                   my_socket sd, HANDLE hPipe, uint flags);
-int	vio_read(Vio *vio, gptr	buf, int size);
-int     vio_read_buff(Vio *vio, gptr buf, int size);
-int	vio_write(Vio *vio, const gptr buf, int size);
+size_t	vio_read(Vio *vio, uchar *	buf, size_t size);
+size_t  vio_read_buff(Vio *vio, uchar * buf, size_t size);
+size_t	vio_write(Vio *vio, const uchar * buf, size_t size);
 int	vio_blocking(Vio *vio, my_bool onoff, my_bool *old_mode);
 my_bool	vio_is_blocking(Vio *vio);
 /* setsockopt TCP_NODELAY at IPPROTO_TCP level, when possible */
@@ -128,8 +128,8 @@ void free_vio_ssl_acceptor_fd(struct st_VioSSLFd *fd);
 #endif /* HAVE_OPENSSL */
 
 #ifdef HAVE_SMEM
-int vio_read_shared_memory(Vio *vio, gptr buf, int size);
-int vio_write_shared_memory(Vio *vio, const gptr buf, int size);
+size_t vio_read_shared_memory(Vio *vio, uchar * buf, size_t size);
+size_t vio_write_shared_memory(Vio *vio, const uchar * buf, size_t size);
 int vio_close_shared_memory(Vio * vio);
 #endif
 
@@ -187,8 +187,8 @@ struct st_vio
   /* function pointers. They are similar for socket/SSL/whatever */
   void    (*viodelete)(Vio*);
   int     (*vioerrno)(Vio*);
-  int     (*read)(Vio*, gptr, int);
-  int     (*write)(Vio*, const gptr, int);
+  size_t  (*read)(Vio*, uchar *, size_t);
+  size_t  (*write)(Vio*, const uchar *, size_t);
   int     (*vioblocking)(Vio*, my_bool, my_bool *);
   my_bool (*is_blocking)(Vio*);
   int     (*viokeepalive)(Vio*, my_bool);
@@ -210,7 +210,7 @@ struct st_vio
   HANDLE  event_client_wrote;
   HANDLE  event_client_read;
   HANDLE  event_conn_closed;
-  long    shared_memory_remain;
+  size_t  shared_memory_remain;
   char    *shared_memory_pos;
   NET     *net;
 #endif /* HAVE_SMEM */