Adding upstream version 1:10.11.6.upstream/1%10.11.6upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 109 insertions, 0 deletions

diff --git a/storage/myisam/mi_cache.c b/storage/myisam/mi_cache.c
new file mode 100644
index 00000000..9a6c4044
--- /dev/null
+++ b/storage/myisam/mi_cache.c
@@ -0,0 +1,109 @@
+/* Copyright (c) 2000-2003, 2005-2007 MySQL AB, 2009 Sun Microsystems, Inc.
+   Use is subject to license terms.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */
+
+/*
+  Functions for read record cacheing with myisam
+  Used for reading dynamic/compressed records from datafile.
+
+  Can fetch data directly from file (outside cache),
+  if reading a small chunk straight before the cached part (with possible
+  overlap).
+
+  Can be explicitly asked not to use cache (by not setting READING_NEXT in
+  flag) - useful for occasional out-of-cache reads, when the next read is
+  expected to hit the cache again.
+
+  Allows "partial read" errors in the record header (when READING_HEADER flag
+  is set) - unread part is bzero'ed
+
+  Note: out-of-cache reads are enabled for shared IO_CACHE's too,
+  as these reads will be cached by OS cache (and mysql_file_pread is always atomic)
+*/
+
+#include "myisamdef.h"
+
+int _mi_read_cache(IO_CACHE *info, uchar *buff, my_off_t pos, size_t length,
+		   int flag)
+{
+  size_t read_length,in_buff_length;
+  my_off_t offset;
+  uchar *in_buff_pos;
+  DBUG_ENTER("_mi_read_cache");
+  DBUG_ASSERT(!(info->myflags & MY_ENCRYPT));
+
+  if (pos < info->pos_in_file)
+  {
+    read_length=length;
+    if ((my_off_t) read_length > (my_off_t) (info->pos_in_file-pos))
+      read_length=(size_t)(info->pos_in_file-pos);
+    info->seek_not_done=1;
+    if (mysql_file_pread(info->file, buff, read_length, pos, MYF(MY_NABP)))
+      DBUG_RETURN(1);
+    if (!(length-=read_length))
+      DBUG_RETURN(0);
+    pos+=read_length;
+    buff+=read_length;
+  }
+  if (pos >= info->pos_in_file &&
+      (offset= (my_off_t) (pos - info->pos_in_file)) <
+      (my_off_t) (info->read_end - info->request_pos))
+  {
+    in_buff_pos=info->request_pos+ (uint)offset;
+    in_buff_length= MY_MIN(length, (size_t)(info->read_end-in_buff_pos));
+    memcpy(buff,info->request_pos+(uint) offset, in_buff_length);
+    if (!(length-=in_buff_length))
+      DBUG_RETURN(0);
+    pos+=in_buff_length;
+    buff+=in_buff_length;
+  }
+  else
+    in_buff_length=0;
+  if (flag & READING_NEXT)
+  {
+    if (pos != (info->pos_in_file +
+		(uint) (info->read_end - info->request_pos)))
+    {
+      info->pos_in_file=pos;				/* Force start here */
+      info->read_pos=info->read_end=info->request_pos;	/* Everything used */
+      info->seek_not_done=1;
+    }
+    else
+      info->read_pos=info->read_end;			/* All block used */
+    if (!_my_b_read(info,buff,length))
+      DBUG_RETURN(0);
+    read_length=info->error;
+  }
+  else
+  {
+    info->seek_not_done=1;
+    if ((read_length= mysql_file_pread(info->file, buff, length, pos,
+                                       MYF(0))) == length)
+      DBUG_RETURN(0);
+  }
+  if (!(flag & READING_HEADER) || (int) read_length == -1 ||
+      read_length+in_buff_length < 3)
+  {
+    DBUG_PRINT("error",
+               ("Error %d reading next-multi-part block (Got %d bytes)",
+                my_errno, (int) read_length));
+    if (!my_errno || my_errno == -1 || my_errno == HA_ERR_FILE_TOO_SHORT)
+      my_errno= HA_ERR_WRONG_IN_RECORD;
+    DBUG_RETURN(1);
+  }
+  bzero(buff+read_length,MI_BLOCK_INFO_HEADER_LENGTH - in_buff_length -
+        read_length);
+  DBUG_RETURN(0);
+} /* _mi_read_cache */