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Diffstat (limited to 'sql/mf_iocache.cc')
-rw-r--r-- | sql/mf_iocache.cc | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/sql/mf_iocache.cc b/sql/mf_iocache.cc new file mode 100644 index 00000000..a8087ed5 --- /dev/null +++ b/sql/mf_iocache.cc @@ -0,0 +1,97 @@ +/* Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. + + 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 */ + +/** + @file + + @details + Caching of files with only does (sequential) read or writes of fixed- + length records. A read isn't allowed to go over file-length. A read is ok + if it ends at file-length and next read can try to read after file-length + (and get a EOF-error). + Possibly use of asyncronic io. + macros for read and writes for faster io. + Used instead of FILE when reading or writing whole files. + This will make mf_rec_cache obsolete. + One can change info->pos_in_file to a higher value to skip bytes in file if + also info->read_pos is set to info->read_end. + If called through open_cached_file(), then the temporary file will + only be created if a write exeeds the file buffer or if one calls + flush_io_cache(). +*/ + +#include "mariadb.h" +#include "sql_priv.h" +#include "sql_class.h" // THD +#ifdef HAVE_REPLICATION + +extern "C" { + +/** + Read buffered from the net. + + @retval + 1 if can't read requested characters + @retval + 0 if record read +*/ + + +int _my_b_net_read(IO_CACHE *info, uchar *Buffer, size_t) +{ + ulong read_length; + NET *net= &(current_thd)->net; + DBUG_ENTER("_my_b_net_read"); + + if (!info->end_of_file) + DBUG_RETURN(1); /* because my_b_get (no _) takes 1 byte at a time */ + read_length= my_net_read_packet(net, 0); + if (unlikely(read_length == packet_error)) + { + info->error= -1; + DBUG_RETURN(1); + } + if (unlikely(read_length == 0)) + { + info->end_of_file= 0; /* End of file from client */ + DBUG_RETURN(1); + } + /* to set up stuff for my_b_get (no _) */ + info->read_end = (info->read_pos = (uchar*) net->read_pos) + read_length; + Buffer[0] = info->read_pos[0]; /* length is always 1 */ + + /* + info->request_pos is used by log_loaded_block() to know the size + of the current block. + info->pos_in_file is used by log_loaded_block() too. + */ + info->pos_in_file+= read_length; + info->request_pos=info->read_pos; + + info->read_pos++; + + DBUG_RETURN(0); +} + +} /* extern "C" */ + +#elif defined(_WIN32) + +// Remove linker warning 4221 about empty file +namespace { char dummy; }; + +#endif /* HAVE_REPLICATION */ + + |