2014-11-19 00:06:40 +08:00
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#ifndef MYSQL_SERVICE_THD_ALLOC_INCLUDED
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/* Copyright (C) 2009 Sun Microsystems, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/**
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@file
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This service provdes functions to allocate memory in a connection local
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memory pool. The memory allocated there will be automatically freed at the
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end of the statement, don't use it for allocations that should live longer
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than that. For short living allocations this is more efficient than
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using my_malloc and friends, and automatic "garbage collection" allows not
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to think about memory leaks.
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The pool is best for small to medium objects, don't use it for large
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allocations - they are better served with my_malloc.
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*/
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#ifndef MYSQL_ABI_CHECK
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#include <stdlib.h>
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#endif
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct st_mysql_lex_string
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{
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char *str;
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size_t length;
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};
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typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
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extern struct thd_alloc_service_st {
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void *(*thd_alloc_func)(MYSQL_THD, unsigned int);
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void *(*thd_calloc_func)(MYSQL_THD, unsigned int);
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char *(*thd_strdup_func)(MYSQL_THD, const char *);
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char *(*thd_strmake_func)(MYSQL_THD, const char *, unsigned int);
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void *(*thd_memdup_func)(MYSQL_THD, const void*, unsigned int);
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MYSQL_LEX_STRING *(*thd_make_lex_string_func)(MYSQL_THD, MYSQL_LEX_STRING *,
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const char *, unsigned int, int);
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} *thd_alloc_service;
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#ifdef MYSQL_DYNAMIC_PLUGIN
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#define thd_alloc(thd,size) (thd_alloc_service->thd_alloc_func((thd), (size)))
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#define thd_calloc(thd,size) (thd_alloc_service->thd_calloc_func((thd), (size)))
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#define thd_strdup(thd,str) (thd_alloc_service->thd_strdup_func((thd), (str)))
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#define thd_strmake(thd,str,size) \
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(thd_alloc_service->thd_strmake_func((thd), (str), (size)))
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#define thd_memdup(thd,str,size) \
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(thd_alloc_service->thd_memdup_func((thd), (str), (size)))
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#define thd_make_lex_string(thd, lex_str, str, size, allocate_lex_string) \
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(thd_alloc_service->thd_make_lex_string_func((thd), (lex_str), (str), \
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(size), (allocate_lex_string)))
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#else
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/**
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Allocate memory in the connection's local memory pool
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@details
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When properly used in place of @c my_malloc(), this can significantly
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improve concurrency. Don't use this or related functions to allocate
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large chunks of memory. Use for temporary storage only. The memory
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will be freed automatically at the end of the statement; no explicit
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code is required to prevent memory leaks.
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@see alloc_root()
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*/
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void *thd_alloc(MYSQL_THD thd, unsigned int size);
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/**
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@see thd_alloc()
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*/
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void *thd_calloc(MYSQL_THD thd, unsigned int size);
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/**
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@see thd_alloc()
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*/
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char *thd_strdup(MYSQL_THD thd, const char *str);
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/**
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@see thd_alloc()
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*/
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char *thd_strmake(MYSQL_THD thd, const char *str, unsigned int size);
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/**
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@see thd_alloc()
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*/
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void *thd_memdup(MYSQL_THD thd, const void* str, unsigned int size);
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/**
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Create a LEX_STRING in this connection's local memory pool
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@param thd user thread connection handle
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@param lex_str pointer to LEX_STRING object to be initialized
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@param str initializer to be copied into lex_str
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@param size length of str, in bytes
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@param allocate_lex_string flag: if TRUE, allocate new LEX_STRING object,
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instead of using lex_str value
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@return NULL on failure, or pointer to the LEX_STRING object
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@see thd_alloc()
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*/
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MYSQL_LEX_STRING *thd_make_lex_string(MYSQL_THD thd, MYSQL_LEX_STRING *lex_str,
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const char *str, unsigned int size,
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int allocate_lex_string);
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#endif
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#ifdef __cplusplus
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}
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#endif
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#define MYSQL_SERVICE_THD_ALLOC_INCLUDED
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#endif
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