hcq/MaxScale
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
Files
55f1bbfce6263e6ff37f287d141716eba9544c5f
MaxScale/include/maxscale/buffer.h
Johan Wikman 265aacaf15 GWBUF_DATA(...) explicitly returns uint8_t*
2016-11-24 13:31:29 +02:00

220 lines
8.6 KiB
C
Raw Blame History

#pragma once
/*
* Copyright (c) 2016 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl.
*
* Change Date: 2019-07-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
/**
* @file buffer.h Definitions relating the gateway buffer manipulation facilities.
*
* These are used to store all data coming in form or going out to the client and the
* backend structures.
*
* The buffers are designed to be used in linked lists and such that they may be passed
* from one side of the gateway to another without the need to copy data. It may be the case
* that not all of the data in the buffer is valid, to this end a start and end pointer are
* included that point to the first valid byte in the buffer and the first byte after the
* last valid byte. This allows data to be consumed from either end of the buffer whilst
* still allowing for the copy free semantics of the buffering system.
*
* @verbatim
* Revision History
*
* Date Who Description
* 10/06/2013 Mark Riddoch Initial implementation
* 11/07/2013 Mark Riddoch Addition of reference count in the gwbuf
* 16/07/2013 Massimiliano Pinto Added command type for the queue
* 10/07/2014 Mark Riddoch Addition of hints
* 15/07/2014 Mark Riddoch Added buffer properties
* 03/10/2014 Martin Brampton Pointer arithmetic standard conformity
* Add more buffer handling macros
* Add gwbuf_rtrim (handle chains)
* 09/11/2014 Martin Brampton Add dprintAllBuffers (conditional compilation)
*
* @endverbatim
*/
#include <maxscale/cdefs.h>
#include <string.h>
#include <maxscale/debug.h>
#include <maxscale/hint.h>
#include <maxscale/spinlock.h>
#include <stdint.h>
MXS_BEGIN_DECLS
/**
* Buffer properties - used to store properties related to the buffer
* contents. This may be added at any point during the processing of the
* data, especially in the protocol stage of the processing.
*/
typedef struct buf_property
{
char *name;
char *value;
struct buf_property *next;
} BUF_PROPERTY;
typedef enum
{
GWBUF_TYPE_UNDEFINED = 0x00,
GWBUF_TYPE_PLAINSQL = 0x01,
GWBUF_TYPE_MYSQL = 0x02,
GWBUF_TYPE_SINGLE_STMT = 0x04,
GWBUF_TYPE_SESCMD_RESPONSE = 0x08,
GWBUF_TYPE_RESPONSE_END = 0x10,
GWBUF_TYPE_SESCMD = 0x20,
GWBUF_TYPE_HTTP = 0x40
} gwbuf_type_t;
#define GWBUF_IS_TYPE_UNDEFINED(b) (b->gwbuf_type == 0)
#define GWBUF_IS_TYPE_PLAINSQL(b) (b->gwbuf_type & GWBUF_TYPE_PLAINSQL)
#define GWBUF_IS_TYPE_MYSQL(b) (b->gwbuf_type & GWBUF_TYPE_MYSQL)
#define GWBUF_IS_TYPE_SINGLE_STMT(b) (b->gwbuf_type & GWBUF_TYPE_SINGLE_STMT)
#define GWBUF_IS_TYPE_SESCMD_RESPONSE(b) (b->gwbuf_type & GWBUF_TYPE_SESCMD_RESPONSE)
#define GWBUF_IS_TYPE_RESPONSE_END(b) (b->gwbuf_type & GWBUF_TYPE_RESPONSE_END)
#define GWBUF_IS_TYPE_SESCMD(b) (b->gwbuf_type & GWBUF_TYPE_SESCMD)
/**
* A structure to encapsulate the data in a form that the data itself can be
* shared between multiple GWBUF's without the need to make multiple copies
* but still maintain separate data pointers.
*/
typedef struct
{
unsigned char *data; /*< Physical memory that was allocated */
int refcount; /*< Reference count on the buffer */
} SHARED_BUF;
typedef enum
{
GWBUF_INFO_NONE = 0x0,
GWBUF_INFO_PARSED = 0x1
} gwbuf_info_t;
#define GWBUF_IS_PARSED(b) (b->gwbuf_info & GWBUF_INFO_PARSED)
/**
* A structure for cleaning up memory allocations of structures which are
* referred to by GWBUF and deallocated in gwbuf_free but GWBUF doesn't
* know what they are.
* All functions on the list are executed before freeing memory of GWBUF struct.
*/
typedef enum
{
GWBUF_PARSING_INFO
} bufobj_id_t;
typedef struct buffer_object_st buffer_object_t;
struct buffer_object_st
{
bufobj_id_t bo_id;
void* bo_data;
void (*bo_donefun_fp)(void *);
buffer_object_t* bo_next;
};
/**
* The buffer structure used by the descriptor control blocks.
*
* Linked lists of buffers are created as data is read from a descriptor
* or written to a descriptor. The use of linked lists of buffers with
* flexible data pointers is designed to minimise the need for data to
* be copied within the gateway.
*/
typedef struct gwbuf
{
SPINLOCK gwbuf_lock;
struct gwbuf *next; /*< Next buffer in a linked chain of buffers */
struct gwbuf *tail; /*< Last buffer in a linked chain of buffers */
void *start; /*< Start of the valid data */
void *end; /*< First byte after the valid data */
SHARED_BUF *sbuf; /*< The shared buffer with the real data */
buffer_object_t *gwbuf_bufobj; /*< List of objects referred to by GWBUF */
gwbuf_info_t gwbuf_info; /*< Info bits */
gwbuf_type_t gwbuf_type; /*< buffer's data type information */
HINT *hint; /*< Hint data for this buffer */
BUF_PROPERTY *properties; /*< Buffer properties */
} GWBUF;
/*<
* Macros to access the data in the buffers
*/
/*< First valid, unconsumed byte in the buffer */
#define GWBUF_DATA(b) ((uint8_t*)(b)->start)
/*< Number of bytes in the individual buffer */
#define GWBUF_LENGTH(b) ((char *)(b)->end - (char *)(b)->start)
/*< Return the byte at offset byte from the start of the unconsumed portion of the buffer */
#define GWBUF_DATA_CHAR(b, byte) (GWBUF_LENGTH(b) < ((byte)+1) ? -1 : *(((char *)(b)->start)+4))
/*< Check that the data in a buffer has the SQL marker*/
#define GWBUF_IS_SQL(b) (0x03 == GWBUF_DATA_CHAR(b,4))
/*< Check whether the buffer is contiguous*/
#define GWBUF_IS_CONTIGUOUS(b) (((b) == NULL) || ((b)->next == NULL))
/*< True if all bytes in the buffer have been consumed */
#define GWBUF_EMPTY(b) ((char *)(b)->start >= (char *)(b)->end)
/*< Consume a number of bytes in the buffer */
#define GWBUF_CONSUME(b, bytes) ((b)->start = bytes > ((char *)(b)->end - (char *)(b)->start) ? (b)->end : (void *)((char *)(b)->start + (bytes)));
/*< Check if a given pointer is within the buffer */
#define GWBUF_POINTER_IN_BUFFER (ptr, b)\
((char *)(ptr) >= (char *)(b)->start && (char *)(ptr) < (char *)(b)->end)
/*< Consume a complete buffer */
#define GWBUF_CONSUME_ALL(b) gwbuf_consume((b), GWBUF_LENGTH((b)))
#define GWBUF_RTRIM(b, bytes)\
((b)->end = bytes > ((char *)(b)->end - (char *)(b)->start) ? (b)->start : \
(void *)((char *)(b)->end - (bytes)));
#define GWBUF_TYPE(b) (b)->gwbuf_type
/*<
* Function prototypes for the API to maniplate the buffers
*/
extern GWBUF *gwbuf_alloc(unsigned int size);
extern GWBUF *gwbuf_alloc_and_load(unsigned int size, const void *data);
extern void gwbuf_free(GWBUF *buf);
extern GWBUF *gwbuf_clone(GWBUF *buf);
extern GWBUF *gwbuf_append(GWBUF *head, GWBUF *tail);
extern GWBUF *gwbuf_consume(GWBUF *head, unsigned int length);
extern GWBUF *gwbuf_trim(GWBUF *head, unsigned int length);
extern GWBUF *gwbuf_rtrim(GWBUF *head, unsigned int length);
extern unsigned int gwbuf_length(GWBUF *head);
extern int gwbuf_count(GWBUF *head);
extern size_t gwbuf_copy_data(GWBUF *buffer, size_t offset, size_t bytes,
uint8_t* dest);
extern GWBUF *gwbuf_split(GWBUF **buf, size_t length);
extern GWBUF *gwbuf_clone_transform(GWBUF *head, gwbuf_type_t type);
extern GWBUF *gwbuf_clone_all(GWBUF* head);
extern void gwbuf_set_type(GWBUF *head, gwbuf_type_t type);
extern int gwbuf_add_property(GWBUF *buf, char *name, char *value);
extern char *gwbuf_get_property(GWBUF *buf, char *name);
extern GWBUF *gwbuf_make_contiguous(GWBUF *);
extern int gwbuf_add_hint(GWBUF *, HINT *);
void gwbuf_add_buffer_object(GWBUF* buf,
bufobj_id_t id,
void* data,
void (*donefun_fp)(void *));
void* gwbuf_get_buffer_object_data(GWBUF* buf, bufobj_id_t id);
#if defined(BUFFER_TRACE)
extern void dprintAllBuffers(void *pdcb);
#endif
MXS_END_DECLS
Reference in New Issue View Git Blame Copy Permalink