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

1 files changed, 73 insertions, 80 deletions

diff --git a/mysys/my_pread.c b/mysys/my_pread.c
index f8f0fa49c10..070494e4f1d 100644
--- a/mysys/my_pread.c
+++ b/mysys/my_pread.c
@@ -20,61 +20,57 @@
 #include <unistd.h>
 #endif
 
-	/* Read a chunk of bytes from a file  */
-
-uint my_pread(File Filedes, byte *Buffer, uint Count, my_off_t offset,
-	      myf MyFlags)
+/*
+  Read a chunk of bytes from a file from a given position
+
+  SYNOPSIOS
+    my_pread()
+    Filedes	File decsriptor
+    Buffer	Buffer to read data into
+    Count	Number of bytes to read
+    offset	Position to read from
+    MyFlags	Flags
+
+  NOTES
+    This differs from the normal pread() call in that we don't care
+    to set the position in the file back to the original position
+    if the system doesn't support pread().
+
+  RETURN
+    (size_t) -1   Error
+    #             Number of bytes read
+*/
+
+size_t my_pread(File Filedes, uchar *Buffer, size_t Count, my_off_t offset,
+                myf MyFlags)
 {
-  uint readbytes;
+  size_t readbytes;
   int error= 0;
   DBUG_ENTER("my_pread");
   DBUG_PRINT("my",("Fd: %d  Seek: %lu  Buffer: 0x%lx  Count: %u  MyFlags: %d",
-		   Filedes, (ulong) offset, (long) Buffer, Count, MyFlags));
-
+		   Filedes, (ulong) offset, (long) Buffer, (uint) Count,
+                   MyFlags));
   for (;;)
   {
 #ifndef __WIN__
     errno=0;					/* Linux doesn't reset this */
 #endif
 #ifndef HAVE_PREAD
-    os_off_t old_offset;
-
     pthread_mutex_lock(&my_file_info[Filedes].mutex);
-    /*
-      As we cannot change the file pointer, we save the old position,
-      before seeking to the given offset
-    */
-
-    error= (old_offset= lseek(Filedes, 0L, MY_SEEK_CUR)) == -1L ||
-           lseek(Filedes, offset, MY_SEEK_SET) == -1L;
-
-    if (!error)                                 /* Seek was successful */
-    {
-      if ((readbytes = (uint) read(Filedes, Buffer, Count)) == -1L)
-        my_errno= errno;
-
-      /*
-        We should seek back, even if read failed. If this fails,
-        we will return an error. If read failed as well, we will
-        save the errno from read, not from lseek().
-      */
-      if ((error= (lseek(Filedes, old_offset, MY_SEEK_SET) == -1L)) &&
-          readbytes != -1L)
-        my_errno= errno;
-    }
-
+    readbytes= (uint) -1;
+    error= (lseek(Filedes, offset, MY_SEEK_SET) == (my_off_t) -1 ||
+	    (readbytes= read(Filedes, Buffer, Count)) != Count);
     pthread_mutex_unlock(&my_file_info[Filedes].mutex);
 #else
-    if ((error= ((readbytes =
-                  (uint) pread(Filedes, Buffer, Count, offset)) != Count)))
+    if ((error= ((readbytes= pread(Filedes, Buffer, Count, offset)) != Count)))
       my_errno= errno;
 #endif
     if (error || readbytes != Count)
     {
       DBUG_PRINT("warning",("Read only %d bytes off %u from %d, errno: %d",
-			    (int) readbytes, Count,Filedes,my_errno));
+			    (int) readbytes, (uint) Count,Filedes,my_errno));
 #ifdef THREAD
-      if ((readbytes == 0 || (int) readbytes == -1) && errno == EINTR)
+      if ((readbytes == 0 || readbytes == (size_t) -1) && errno == EINTR)
       {
         DBUG_PRINT("debug", ("my_pread() was interrupted and returned %d",
                              (int) readbytes));
@@ -83,14 +79,14 @@ uint my_pread(File Filedes, byte *Buffer, uint Count, my_off_t offset,
 #endif
       if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
       {
-	if ((int) readbytes == -1)
+	if (readbytes == (size_t) -1)
 	  my_error(EE_READ, MYF(ME_BELL+ME_WAITTANG),
 		   my_filename(Filedes),my_errno);
 	else if (MyFlags & (MY_NABP | MY_FNABP))
 	  my_error(EE_EOFERR, MYF(ME_BELL+ME_WAITTANG),
 		   my_filename(Filedes),my_errno);
       }
-      if ((int) readbytes == -1 || (MyFlags & (MY_FNABP | MY_NABP)))
+      if (readbytes == (size_t) -1 || (MyFlags & (MY_FNABP | MY_NABP)))
 	DBUG_RETURN(MY_FILE_ERROR);		/* Return with error */
     }
     if (MyFlags & (MY_NABP | MY_FNABP))
@@ -100,65 +96,63 @@ uint my_pread(File Filedes, byte *Buffer, uint Count, my_off_t offset,
 } /* my_pread */
 
 
-	/* Write a chunk of bytes to a file */
+/*
+  Write a chunk of bytes to a file at a given position
+
+  SYNOPSIOS
+    my_pwrite()
+    Filedes	File decsriptor
+    Buffer	Buffer to write data from
+    Count	Number of bytes to write
+    offset	Position to write to
+    MyFlags	Flags
+
+  NOTES
+    This differs from the normal pwrite() call in that we don't care
+    to set the position in the file back to the original position
+    if the system doesn't support pwrite()
 
-uint my_pwrite(int Filedes, const byte *Buffer, uint Count, my_off_t offset,
-	       myf MyFlags)
+  RETURN
+    (size_t) -1   Error
+    #             Number of bytes read
+ */
+
+size_t my_pwrite(int Filedes, const uchar *Buffer, size_t Count,
+                 my_off_t offset, myf MyFlags)
 {
-  uint writenbytes,errors;
-  ulong written;
+  size_t writenbytes, written;
+  uint errors;
   DBUG_ENTER("my_pwrite");
-  DBUG_PRINT("my",("Fd: %d  Seek: %lu  Buffer: 0x%lx  Count: %d  MyFlags: %d",
-		   Filedes, (ulong) offset, (long) Buffer, Count, MyFlags));
-  errors=0; written=0L;
+  DBUG_PRINT("my",("Fd: %d  Seek: %lu  Buffer: 0x%lx  Count: %u  MyFlags: %d",
+		   Filedes, (ulong) offset, (long) Buffer, (uint) Count,
+                   MyFlags));
+  errors= 0;
+  written= 0;
 
   for (;;)
   {
 #ifndef HAVE_PREAD
-    int error= 0;
-    os_off_t old_offset;
-    writenbytes= (uint) -1;
+    int error;
+    writenbytes= (size_t) -1;
     pthread_mutex_lock(&my_file_info[Filedes].mutex);
-
-    /*
-      As we cannot change the file pointer, we save the old position,
-      before seeking to the given offset
-    */
-    error= ((old_offset= lseek(Filedes, 0L, MY_SEEK_CUR)) == -1L ||
-            lseek(Filedes, offset, MY_SEEK_SET) == -1L);
-
-    if (!error)                                 /* Seek was successful */
-    {
-      if ((writenbytes = (uint) write(Filedes, Buffer, Count)) == -1L)
-        my_errno= errno;
-
-      /*
-        We should seek back, even if write failed. If this fails,
-        we will return an error. If write failed as well, we will
-        save the errno from write, not from lseek().
-      */
-      if ((error= (lseek(Filedes, old_offset, MY_SEEK_SET) == -1L)) &&
-          writenbytes != -1L)
-        my_errno= errno;
-    }
+    error= (lseek(Filedes, offset, MY_SEEK_SET) != (my_off_t) -1 &&
+            (writenbytes = write(Filedes, Buffer, Count)) == Count);
     pthread_mutex_unlock(&my_file_info[Filedes].mutex);
-
-    if (!error && writenbytes == Count)
+    if (error)
       break;
 #else
-    if ((writenbytes = (uint) pwrite(Filedes, Buffer, Count,offset)) == Count)
+    if ((writenbytes= pwrite(Filedes, Buffer, Count,offset)) == Count)
       break;
-    else
-      my_errno= errno;
+    my_errno= errno;
 #endif
-    if ((int) writenbytes != -1)
+    if (writenbytes != (size_t) -1)
     {					/* Safegueard */
       written+=writenbytes;
       Buffer+=writenbytes;
       Count-=writenbytes;
       offset+=writenbytes;
     }
-    DBUG_PRINT("error",("Write only %d bytes",writenbytes));
+    DBUG_PRINT("error",("Write only %u bytes", (uint) writenbytes));
 #ifndef NO_BACKGROUND
 #ifdef THREAD
     if (my_thread_var->abort)
@@ -173,8 +167,7 @@ uint my_pwrite(int Filedes, const byte *Buffer, uint Count, my_off_t offset,
       VOID(sleep(MY_WAIT_FOR_USER_TO_FIX_PANIC));
       continue;
     }
-    if ((writenbytes > 0 && (uint) writenbytes != (uint) -1) ||
-        my_errno == EINTR)
+    if ((writenbytes && writenbytes != (size_t) -1) || my_errno == EINTR)
       continue;					/* Retry */
 #endif
     if (MyFlags & (MY_NABP | MY_FNABP))