sql_map.cpp
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:3k
- /* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
- 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; either version 2 of the License, or
- (at your option) any later version.
- 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
- #ifdef USE_PRAGMA_IMPLEMENTATION
- #pragma implementation // gcc: Class implementation
- #endif
- #include "mysql_priv.h"
- #ifdef HAVE_MMAP
- #include <sys/mman.h>
- #include <sys/stat.h>
- #endif
- #ifndef MAP_NORESERVE
- #define MAP_NORESERVE 0 // For IRIX
- #endif
- mapped_files::mapped_files(const my_string filename,byte *magic,uint magic_length)
- {
- #ifdef HAVE_MMAP
- name=my_strdup(filename,MYF(0));
- use_count=1;
- error=0;
- map=0;
- size=0;
- if ((file=my_open(name,O_RDONLY,MYF(MY_WME))) >= 0)
- {
- struct stat stat_buf;
- if (!fstat(file,&stat_buf))
- {
- if (!(map=(byte*) mmap(0,(size=(ulong) stat_buf.st_size),PROT_READ,
- MAP_SHARED | MAP_NORESERVE,file,
- 0L)))
- {
- error=errno;
- my_printf_error(0,"Can't map file: %s, errno: %d",MYF(0),
- (my_string) name,error);
- }
- }
- if (map && memcmp(map,magic,magic_length))
- {
- my_printf_error(0,"Wrong magic in %s",MYF(0),name);
- VOID(munmap(map,size));
- map=0;
- }
- if (!map)
- {
- VOID(my_close(file,MYF(0)));
- file= -1;
- }
- }
- #endif
- }
- mapped_files::~mapped_files()
- {
- #ifdef HAVE_MMAP
- if (file >= 0)
- {
- VOID(munmap((caddr_t) map,size));
- VOID(my_close(file,MYF(0)));
- file= -1; map=0;
- }
- my_free(name,MYF(0));
- #endif
- }
- static I_List<mapped_files> maps_in_use;
- /*
- ** Check if a file is mapped. If it is, then return pointer to old map,
- ** else alloc new object
- */
- mapped_files *map_file(const my_string name,byte *magic,uint magic_length)
- {
- #ifdef HAVE_MMAP
- VOID(pthread_mutex_lock(&LOCK_mapped_file));
- I_List_iterator<mapped_files> list(maps_in_use);
- mapped_files *map;
- char path[FN_REFLEN];
- sprintf(path,"%s/%s/%s.uniq",mysql_data_home,current_thd->db,name);
- (void) unpack_filename(path,path);
- while ((map=list++))
- {
- if (!strcmp(path,map->name))
- break;
- }
- if (!map)
- {
- map=new mapped_files(path,magic,magic_length);
- maps_in_use.append(map);
- }
- else
- {
- map->use_count++;
- if (!map->map)
- my_printf_error(0,"Can't map file: %s, error: %d",MYF(0),path,
- map->error);
- }
- VOID(pthread_mutex_unlock(&LOCK_mapped_file));
- return map;
- #else
- return NULL;
- #endif
- }
- /*
- ** free the map if there are no more users for it
- */
- void unmap_file(mapped_files *map)
- {
- #ifdef HAVE_MMAP
- VOID(pthread_mutex_lock(&LOCK_mapped_file));
- if (!map->use_count--)
- delete map;
- VOID(pthread_mutex_unlock(&LOCK_mapped_file));
- #endif
- }
- /*****************************************************************************
- ** Instansiate templates
- *****************************************************************************/
- #ifdef __GNUC__
- /* Used templates */
- template class I_List<mapped_files>;
- template class I_List_iterator<mapped_files>;
- #endif