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/* Copyright (c) 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 */
#include <my_global.h>
#include "datadict.h"
#include "sql_priv.h"
#include "sql_class.h"
#include "sql_table.h"
static int read_string(File file, uchar**to, size_t length)
{
DBUG_ENTER("read_string");
my_free(*to);
if (!(*to= (uchar*) my_malloc(length+1,MYF(MY_WME))) ||
mysql_file_read(file, *to, length, MYF(MY_NABP)))
{
my_free(*to);
*to= 0;
DBUG_RETURN(1);
}
*((char*) *to+length)= '\0'; // C-style safety
DBUG_RETURN (0);
}
/**
Check type of .frm if we are not going to parse it.
@param[in] thd The current session.
@param[in] path path to FRM file.
@param[in/out] engine_name table engine name (length < NAME_CHAR_LEN)
engine_name is a LEX_STRING, where engine_name->str must point to
a buffer of at least NAME_CHAR_LEN+1 bytes.
If engine_name is 0, then the function will only test if the file is a
view or not
@retval FRMTYPE_ERROR error
@retval FRMTYPE_TABLE table
@retval FRMTYPE_VIEW view
*/
frm_type_enum dd_frm_type(THD *thd, char *path, LEX_STRING *engine_name)
{
File file;
uchar header[10]; //"TYPE=VIEW\n" it is 10 characters
size_t error;
frm_type_enum type= FRMTYPE_ERROR;
uchar dbt;
DBUG_ENTER("dd_frm_type");
if ((file= mysql_file_open(key_file_frm, path, O_RDONLY | O_SHARE, MYF(0))) < 0)
DBUG_RETURN(FRMTYPE_ERROR);
error= mysql_file_read(file, (uchar*) header, sizeof(header), MYF(MY_NABP));
if (error)
goto err;
if (!strncmp((char*) header, "TYPE=VIEW\n", sizeof(header)))
{
type= FRMTYPE_VIEW;
goto err;
}
/*
We return FRMTYPE_TABLE if we can read the .frm file. This allows us
to drop a bad .frm file with DROP TABLE
*/
type= FRMTYPE_TABLE;
/* engine_name is 0 if we only want to know if table is view or not */
if (!engine_name)
goto err;
/* Initialize engine name in case we are not able to find it out */
engine_name->length= 0;
engine_name->str[0]= 0;
if (!is_binary_frm_header(header))
goto err;
dbt= header[3];
/* cannot use ha_resolve_by_legacy_type without a THD */
if (thd && dbt < DB_TYPE_FIRST_DYNAMIC)
{
handlerton *ht= ha_resolve_by_legacy_type(thd, (enum legacy_db_type)dbt);
if (ht)
{
*engine_name= hton2plugin[ht->slot]->name;
goto err;
}
}
/* read the true engine name */
{
MY_STAT state;
uchar *frm_image= 0;
uint n_length;
if (mysql_file_fstat(file, &state, MYF(MY_WME)))
goto err;
if (mysql_file_seek(file, 0, SEEK_SET, MYF(MY_WME)))
goto err;
if (read_string(file, &frm_image, state.st_size))
goto err;
if ((n_length= uint4korr(frm_image+55)))
{
uint record_offset= uint2korr(frm_image+6)+
((uint2korr(frm_image+14) == 0xffff ?
uint4korr(frm_image+47) : uint2korr(frm_image+14)));
uint reclength= uint2korr(frm_image+16);
uchar *next_chunk= frm_image + record_offset + reclength;
uchar *buff_end= next_chunk + n_length;
uint connect_string_length= uint2korr(next_chunk);
next_chunk+= connect_string_length + 2;
if (next_chunk + 2 < buff_end)
{
uint len= uint2korr(next_chunk);
if (len <= NAME_CHAR_LEN)
strmake(engine_name->str, (char*)next_chunk + 2,
engine_name->length= len);
}
}
my_free(frm_image);
}
/* Probably a table. */
err:
mysql_file_close(file, MYF(MY_WME));
DBUG_RETURN(type);
}
/*
Regenerate a metadata locked table.
@param thd Thread context.
@param db Name of the database to which the table belongs to.
@param name Table name.
@param path For temporary tables only - path to table files.
Otherwise NULL (the path is calculated from db and table names).
@retval FALSE Success.
@retval TRUE Error.
*/
bool dd_recreate_table(THD *thd, const char *db, const char *table_name,
const char *path)
{
bool error= TRUE;
HA_CREATE_INFO create_info;
char path_buf[FN_REFLEN + 1];
DBUG_ENTER("dd_recreate_table");
memset(&create_info, 0, sizeof(create_info));
if (path)
create_info.options|= HA_LEX_CREATE_TMP_TABLE;
else
{
build_table_filename(path_buf, sizeof(path_buf) - 1,
db, table_name, "", 0);
path= path_buf;
/* There should be a exclusive metadata lock on the table. */
DBUG_ASSERT(thd->mdl_context.is_lock_owner(MDL_key::TABLE, db, table_name,
MDL_EXCLUSIVE));
}
/* Attempt to reconstruct the table. */
error= ha_create_table(thd, path, db, table_name, &create_info, NULL);
DBUG_RETURN(error);
}
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