59 lines
1.8 KiB
C
59 lines
1.8 KiB
C
#ifndef __REPLICA_SHM_H__
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#define __REPLICA_SHM_H__
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#include <stdint.h>
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#include <stddef.h>
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#ifndef REPLICA_SHM_NAME
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#define REPLICA_SHM_NAME "/kvs_replica_shm"
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#endif
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#ifndef REPLICA_SHM_SIZE
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// 64MB，按需调
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#define REPLICA_SHM_SIZE (256u * 1024u * 1024u)
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#endif
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// 每条记录头部（放在 shm 的 data 区里）
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typedef struct __attribute__((packed)) {
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uint64_t seq; // 单调递增
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uint32_t len; // payload bytes
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uint32_t flags; // 预留：压缩、类型等
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uint32_t crc32; // 可选：0 表示不校验
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uint32_t reserved; // 对齐
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// uint8_t payload[len] 紧跟其后
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} replica_rec_hdr_t;
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// shm 顶部元数据
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typedef struct __attribute__((packed)) {
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uint32_t magic;
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uint32_t version;
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uint64_t capacity; // data 区大小（字节）
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uint64_t write_off; // producer 写指针（0..capacity-1）
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uint64_t last_seq; // producer 最新 seq
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uint8_t _pad[64]; // cacheline padding
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// 后面紧跟 data[capacity]
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} replica_shm_hdr_t;
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typedef struct {
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int fd;
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size_t map_size;
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replica_shm_hdr_t *hdr;
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uint8_t *data;
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} replica_shm_t;
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// kvstore: 初始化（create/open + mmap）
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int replica_shm_open(replica_shm_t *s, const char *name, size_t total_size, int create);
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// kvstore: append 一条记录，返回 off（相对 data 起始），用于 notify
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// 单写者设计：无需锁。返回 0 成功，<0 失败（空间不足或参数错误）
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int replica_shm_append(replica_shm_t *s, uint64_t seq, const void *buf, uint32_t len, uint32_t *out_off);
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// replicator: 读取记录头（不移动游标），你也可以直接 memcpy payload
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// off 是 data 内偏移
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int replica_shm_peek(replica_shm_t *s, uint32_t off, replica_rec_hdr_t *out_hdr);
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// 关闭
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void replica_shm_close(replica_shm_t *s);
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extern replica_shm_t g_rep_shm;
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#endif |