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Merge mysql.com:/home/mydev/mysql-5.1

Browse source 
into  mysql.com:/home/mydev/mysql-5.1-bug11527


client/mysqlcheck.c:
  Auto merged
mysql-test/r/innodb.result:
  Auto merged
mysql-test/r/myisam.result:
  Auto merged
This commit is contained in:
unknown 2006-02-17 14:31:20 +01:00
commit 9525b96c30
1 changed files with 75 additions and 28 deletions
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103
mysys/mf_iocache.c
View file

@ -399,11 +399,31 @@ my_bool reinit_io_cache(IO_CACHE *info, enum cache_type type,
/*
Read buffered. Returns 1 if can't read requested characters
This function is only called from the my_b_read() macro
when there isn't enough characters in the buffer to
satisfy the request.
Returns 0 we succeeded in reading all data
Read buffered.
SYNOPSIS
_my_b_read()
info IO_CACHE pointer
Buffer Buffer to retrieve count bytes from file
Count Number of bytes to read into Buffer
NOTE
This function is only called from the my_b_read() macro when there
isn't enough characters in the buffer to satisfy the request.
WARNING
When changing this function, be careful with handling file offsets
(end-of_file, pos_in_file). Do not cast them to possibly smaller
types than my_off_t unless you can be sure that their value fits.
Same applies to differences of file offsets.
When changing this function, check _my_b_read_r(). It might need the
same change.
RETURN
0 we succeeded in reading all data
1 Error: can't read requested characters
*/
int _my_b_read(register IO_CACHE *info, byte *Buffer, uint Count)
@ -431,7 +451,7 @@ int _my_b_read(register IO_CACHE *info, byte *Buffer, uint Count)
if (Count >= (uint) (IO_SIZE+(IO_SIZE-diff_length)))
{ /* Fill first intern buffer */
uint read_length;
if (info->end_of_file == pos_in_file)
if (info->end_of_file <= pos_in_file)
{ /* End of file */
info->error=(int) left_length;
DBUG_RETURN(1);
@ -546,43 +566,70 @@ static void unlock_io_cache(IO_CACHE *info)
/*
Read from IO_CACHE when it is shared between several threads.
It works as follows: when a thread tries to read from a file
(that is, after using all the data from the (shared) buffer),
it just hangs on lock_io_cache(), wating for other threads.
When the very last thread attempts a read, lock_io_cache()
returns 1, the thread does actual IO and unlock_io_cache(),
which signals all the waiting threads that data is in the buffer.
SYNOPSIS
_my_b_read_r()
info IO_CACHE pointer
Buffer Buffer to retrieve count bytes from file
Count Number of bytes to read into Buffer
NOTE
This function is only called from the my_b_read() macro when there
isn't enough characters in the buffer to satisfy the request.
IMPLEMENTATION
It works as follows: when a thread tries to read from a file (that
is, after using all the data from the (shared) buffer), it just
hangs on lock_io_cache(), wating for other threads. When the very
last thread attempts a read, lock_io_cache() returns 1, the thread
does actual IO and unlock_io_cache(), which signals all the waiting
threads that data is in the buffer.
WARNING
When changing this function, be careful with handling file offsets
(end-of_file, pos_in_file). Do not cast them to possibly smaller
types than my_off_t unless you can be sure that their value fits.
Same applies to differences of file offsets. (Bug #11527)
When changing this function, check _my_b_read(). It might need the
same change.
RETURN
0 we succeeded in reading all data
1 Error: can't read requested characters
*/
int _my_b_read_r(register IO_CACHE *info, byte *Buffer, uint Count)
{
my_off_t pos_in_file;
uint length,diff_length,read_len;
uint length, diff_length, left_length;
DBUG_ENTER("_my_b_read_r");
if ((read_len=(uint) (info->read_end-info->read_pos)))
if ((left_length= (uint) (info->read_end - info->read_pos)))
{
DBUG_ASSERT(Count >= read_len); /* User is not using my_b_read() */
memcpy(Buffer,info->read_pos, (size_t) (read_len));
Buffer+=read_len;
Count-=read_len;
DBUG_ASSERT(Count >= left_length); /* User is not using my_b_read() */
memcpy(Buffer, info->read_pos, (size_t) (left_length));
Buffer+= left_length;
Count-= left_length;
}
while (Count)
{
int cnt, len;
pos_in_file= info->pos_in_file + (uint)(info->read_end - info->buffer);
pos_in_file= info->pos_in_file + (info->read_end - info->buffer);
diff_length= (uint) (pos_in_file & (IO_SIZE-1));
length=IO_ROUND_UP(Count+diff_length)-diff_length;
length=(length <= info->read_length) ?
length + IO_ROUND_DN(info->read_length - length) :
length - IO_ROUND_UP(length - info->read_length) ;
if (info->type != READ_FIFO &&
(length > (uint) (info->end_of_file - pos_in_file)))
(length > (info->end_of_file - pos_in_file)))
length= (uint) (info->end_of_file - pos_in_file);
if (length == 0)
{
info->error=(int) read_len;
info->error= (int) left_length;
DBUG_RETURN(1);
}
if (lock_io_cache(info, pos_in_file))
@ -607,15 +654,15 @@ int _my_b_read_r(register IO_CACHE *info, byte *Buffer, uint Count)
info->seek_not_done=0;
if (len <= 0)
{
info->error=(int) read_len;
info->error= (int) left_length;
DBUG_RETURN(1);
}
cnt=((uint) len > Count) ? (int) Count : len;
memcpy(Buffer,info->read_pos, (size_t)cnt);
Count -=cnt;
Buffer+=cnt;
read_len+=cnt;
info->read_pos+=cnt;
cnt= ((uint) len > Count) ? (int) Count : len;
memcpy(Buffer, info->read_pos, (size_t) cnt);
Count -= cnt;
Buffer+= cnt;
left_length+= cnt;
info->read_pos+= cnt;
}
DBUG_RETURN(0);
}