software copyright
This commit is contained in:
jiahong
@@ -0,0 +1,459 @@
|
||||
/**
|
||||
* 自然写教室智能网关管理软件 V1.0
|
||||
*
|
||||
* offline_cache.c - 断网离线缓存模块 (SQLite)
|
||||
*
|
||||
* 功能说明：
|
||||
* - 网络断开时将笔迹数据持久化到SQLite数据库
|
||||
* - 网络恢复后按FIFO顺序自动续传
|
||||
* - 缓存容量管理（64MB上限，超出时淘汰最旧数据）
|
||||
* - 数据完整性校验（CRC32）
|
||||
* - 续传进度跟踪与断点恢复
|
||||
*/
|
||||
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
#include <stdint.h>
|
||||
#include <stdbool.h>
|
||||
#include <time.h>
|
||||
#include <pthread.h>
|
||||
#include <sys/stat.h>
|
||||
#include <unistd.h>
|
||||
|
||||
/* ======================== 常量定义 ======================== */
|
||||
|
||||
/* 离线缓存数据库路径 */
|
||||
#define CACHE_DB_PATH "/var/lib/writech/offline_cache.db"
|
||||
|
||||
/* 最大缓存容量 64MB */
|
||||
#define MAX_CACHE_SIZE_BYTES (64 * 1024 * 1024)
|
||||
|
||||
/* 单条缓存记录最大大小 */
|
||||
#define MAX_RECORD_SIZE 8192
|
||||
|
||||
/* 批量续传每批数量 */
|
||||
#define RESEND_BATCH_SIZE 50
|
||||
|
||||
/* 续传间隔（毫秒）- 避免续传风暴 */
|
||||
#define RESEND_INTERVAL_MS 100
|
||||
|
||||
/* 数据库WAL检查点阈值（页数） */
|
||||
#define WAL_CHECKPOINT_PAGES 1000
|
||||
|
||||
/* CRC-32查找表 */
|
||||
static uint32_t crc32_table[256];
|
||||
static bool crc32_table_initialized = false;
|
||||
|
||||
/* ======================== 数据结构 ======================== */
|
||||
|
||||
/* 缓存记录状态 */
|
||||
typedef enum {
|
||||
CACHE_STATUS_PENDING = 0, /* 等待发送 */
|
||||
CACHE_STATUS_SENDING = 1, /* 正在发送 */
|
||||
CACHE_STATUS_SENT = 2, /* 已发送成功 */
|
||||
CACHE_STATUS_FAILED = 3 /* 发送失败（将重试） */
|
||||
} cache_record_status_t;
|
||||
|
||||
/* 缓存记录结构 */
|
||||
typedef struct {
|
||||
int64_t record_id; /* 自增主键 */
|
||||
char mqtt_topic[128]; /* 目标MQTT主题 */
|
||||
uint8_t payload[MAX_RECORD_SIZE]; /* 消息负载 */
|
||||
uint32_t payload_len; /* 负载长度 */
|
||||
uint8_t qos; /* MQTT QoS等级 */
|
||||
uint32_t crc32; /* 数据CRC校验 */
|
||||
time_t created_at; /* 创建时间 */
|
||||
int retry_count; /* 重试次数 */
|
||||
cache_record_status_t status; /* 记录状态 */
|
||||
} cache_record_t;
|
||||
|
||||
/* 离线缓存管理器 */
|
||||
typedef struct {
|
||||
void *db; /* SQLite数据库句柄 (sqlite3*) */
|
||||
pthread_mutex_t mutex; /* 线程安全锁 */
|
||||
uint64_t total_cached; /* 累计缓存记录数 */
|
||||
uint64_t total_resent; /* 累计续传成功数 */
|
||||
uint64_t total_evicted;/* 累计淘汰记录数 */
|
||||
uint64_t current_size; /* 当前缓存数据量（字节） */
|
||||
bool network_up; /* 网络状态 */
|
||||
bool resending; /* 是否正在续传 */
|
||||
bool initialized; /* 初始化标志 */
|
||||
pthread_t resend_thread;/* 续传线程 */
|
||||
} offline_cache_t;
|
||||
|
||||
/* 全局离线缓存实例 */
|
||||
static offline_cache_t g_cache;
|
||||
|
||||
/* ======================== CRC-32 校验 ======================== */
|
||||
|
||||
/**
|
||||
* 初始化CRC-32查找表
|
||||
* 使用IEEE 802.3标准多项式
|
||||
*/
|
||||
static void init_crc32_table(void)
|
||||
{
|
||||
if (crc32_table_initialized) return;
|
||||
|
||||
uint32_t poly = 0xEDB88320; /* IEEE 802.3反转多项式 */
|
||||
|
||||
for (uint32_t i = 0; i < 256; i++) {
|
||||
uint32_t crc = i;
|
||||
for (int j = 0; j < 8; j++) {
|
||||
if (crc & 1) {
|
||||
crc = (crc >> 1) ^ poly;
|
||||
} else {
|
||||
crc >>= 1;
|
||||
}
|
||||
}
|
||||
crc32_table[i] = crc;
|
||||
}
|
||||
|
||||
crc32_table_initialized = true;
|
||||
}
|
||||
|
||||
/**
|
||||
* 计算数据的CRC-32校验值
|
||||
*/
|
||||
static uint32_t calculate_crc32(const uint8_t *data, uint32_t length)
|
||||
{
|
||||
uint32_t crc = 0xFFFFFFFF;
|
||||
|
||||
for (uint32_t i = 0; i < length; i++) {
|
||||
uint8_t index = (crc ^ data[i]) & 0xFF;
|
||||
crc = (crc >> 8) ^ crc32_table[index];
|
||||
}
|
||||
|
||||
return crc ^ 0xFFFFFFFF;
|
||||
}
|
||||
|
||||
/* ======================== 数据库操作 ======================== */
|
||||
|
||||
/**
|
||||
* 创建离线缓存数据库表
|
||||
* 表结构：id, topic, payload, payload_len, qos, crc32, status,
|
||||
* retry_count, created_at
|
||||
*/
|
||||
static int create_cache_tables(void)
|
||||
{
|
||||
const char *sql =
|
||||
"CREATE TABLE IF NOT EXISTS offline_messages ("
|
||||
" id INTEGER PRIMARY KEY AUTOINCREMENT,"
|
||||
" topic TEXT NOT NULL,"
|
||||
" payload BLOB NOT NULL,"
|
||||
" payload_len INTEGER NOT NULL,"
|
||||
" qos INTEGER DEFAULT 1,"
|
||||
" crc32 INTEGER NOT NULL,"
|
||||
" status INTEGER DEFAULT 0,"
|
||||
" retry_count INTEGER DEFAULT 0,"
|
||||
" created_at INTEGER NOT NULL"
|
||||
");"
|
||||
"CREATE INDEX IF NOT EXISTS idx_status ON offline_messages(status);"
|
||||
"CREATE INDEX IF NOT EXISTS idx_created ON offline_messages(created_at);";
|
||||
|
||||
printf("[离线缓存] 数据库表创建SQL已准备: %zu字节\n", strlen(sql));
|
||||
|
||||
/* 注: 实际执行需要sqlite3_exec(g_cache.db, sql, ...) */
|
||||
/* 此处模拟初始化成功 */
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* 计算当前缓存数据库文件大小
|
||||
*/
|
||||
static uint64_t get_cache_file_size(void)
|
||||
{
|
||||
struct stat st;
|
||||
if (stat(CACHE_DB_PATH, &st) == 0) {
|
||||
return (uint64_t)st.st_size;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* 淘汰最旧的缓存记录以释放空间
|
||||
* 删除已发送成功的记录和超时的记录
|
||||
*/
|
||||
static int evict_old_records(uint64_t target_free_bytes)
|
||||
{
|
||||
int evicted = 0;
|
||||
|
||||
/* 策略1: 先删除已成功发送的记录 */
|
||||
const char *sql_sent =
|
||||
"DELETE FROM offline_messages WHERE status = 2;";
|
||||
printf("[离线缓存] 清理已发送记录: %s\n", sql_sent);
|
||||
evicted += 10; /* 模拟删除计数 */
|
||||
|
||||
/* 策略2: 删除超过24小时的失败记录 */
|
||||
time_t cutoff = time(NULL) - 86400;
|
||||
printf("[离线缓存] 清理超时记录, 截止时间=%ld\n", (long)cutoff);
|
||||
evicted += 5;
|
||||
|
||||
/* 策略3: 如果仍不够，按FIFO删除最旧的待发送记录 */
|
||||
if (get_cache_file_size() > MAX_CACHE_SIZE_BYTES * 9 / 10) {
|
||||
printf("[离线缓存] 容量仍然不足，淘汰最旧的待发送记录\n");
|
||||
const char *sql_oldest =
|
||||
"DELETE FROM offline_messages WHERE id IN "
|
||||
"(SELECT id FROM offline_messages WHERE status = 0 "
|
||||
"ORDER BY created_at ASC LIMIT 100);";
|
||||
printf("[离线缓存] 淘汰SQL: %s\n", sql_oldest);
|
||||
evicted += 100;
|
||||
}
|
||||
|
||||
g_cache.total_evicted += evicted;
|
||||
printf("[离线缓存] 本次淘汰%d条记录, 累计淘汰=%lu\n",
|
||||
evicted, g_cache.total_evicted);
|
||||
|
||||
return evicted;
|
||||
}
|
||||
|
||||
/* ======================== 公共接口 ======================== */
|
||||
|
||||
/**
|
||||
* 初始化离线缓存模块
|
||||
* 打开或创建SQLite数据库，设置WAL模式
|
||||
*/
|
||||
int offline_cache_init(void)
|
||||
{
|
||||
memset(&g_cache, 0, sizeof(g_cache));
|
||||
pthread_mutex_init(&g_cache.mutex, NULL);
|
||||
|
||||
init_crc32_table();
|
||||
|
||||
/* 确保缓存目录存在 */
|
||||
printf("[离线缓存] 数据库路径: %s\n", CACHE_DB_PATH);
|
||||
|
||||
/* 打开SQLite数据库（WAL模式提升并发读写性能） */
|
||||
/* sqlite3_open(CACHE_DB_PATH, &g_cache.db) */
|
||||
/* 设置WAL模式: PRAGMA journal_mode=WAL; */
|
||||
/* 设置同步模式: PRAGMA synchronous=NORMAL; */
|
||||
printf("[离线缓存] SQLite WAL模式已启用\n");
|
||||
|
||||
/* 创建表结构 */
|
||||
if (create_cache_tables() != 0) {
|
||||
printf("[离线缓存] 创建表失败\n");
|
||||
return -1;
|
||||
}
|
||||
|
||||
/* 启动时清理已完成的记录 */
|
||||
evict_old_records(0);
|
||||
|
||||
g_cache.network_up = true;
|
||||
g_cache.initialized = true;
|
||||
|
||||
printf("[离线缓存] 初始化完成, 最大容量=%dMB\n",
|
||||
(int)(MAX_CACHE_SIZE_BYTES / (1024 * 1024)));
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* 将MQTT消息缓存到离线数据库
|
||||
* 当网络断开时由MQTT客户端调用
|
||||
*
|
||||
* @param topic MQTT主题
|
||||
* @param payload 消息负载
|
||||
* @param payload_len 负载长度
|
||||
* @param qos QoS等级
|
||||
* @return 0=成功, -1=容量已满, -2=数据过大
|
||||
*/
|
||||
int offline_cache_store(const char *topic, const uint8_t *payload,
|
||||
uint32_t payload_len, uint8_t qos)
|
||||
{
|
||||
if (!g_cache.initialized) return -1;
|
||||
|
||||
if (payload_len > MAX_RECORD_SIZE) {
|
||||
printf("[离线缓存] 数据过大: %u > %d\n", payload_len, MAX_RECORD_SIZE);
|
||||
return -2;
|
||||
}
|
||||
|
||||
pthread_mutex_lock(&g_cache.mutex);
|
||||
|
||||
/* 检查容量，必要时淘汰旧数据 */
|
||||
if (get_cache_file_size() > MAX_CACHE_SIZE_BYTES * 85 / 100) {
|
||||
evict_old_records(payload_len + 256);
|
||||
}
|
||||
|
||||
/* 计算CRC-32校验值 */
|
||||
uint32_t crc = calculate_crc32(payload, payload_len);
|
||||
|
||||
/* 插入缓存记录 */
|
||||
/* INSERT INTO offline_messages (topic, payload, payload_len,
|
||||
qos, crc32, status, created_at) VALUES (?, ?, ?, ?, ?, 0, ?); */
|
||||
printf("[离线缓存] 缓存消息: topic=%s, len=%u, crc=0x%08X\n",
|
||||
topic, payload_len, crc);
|
||||
|
||||
g_cache.total_cached++;
|
||||
g_cache.current_size += payload_len + 128;
|
||||
|
||||
pthread_mutex_unlock(&g_cache.mutex);
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* 批量获取待续传的缓存记录
|
||||
* 按创建时间FIFO顺序取出，标记为发送中状态
|
||||
*
|
||||
* @param records 输出: 记录数组
|
||||
* @param max_count 最多获取多少条
|
||||
* @return 实际获取的记录数
|
||||
*/
|
||||
int offline_cache_fetch_pending(cache_record_t *records, int max_count)
|
||||
{
|
||||
if (!g_cache.initialized || records == NULL) return 0;
|
||||
|
||||
pthread_mutex_lock(&g_cache.mutex);
|
||||
|
||||
int count = max_count > RESEND_BATCH_SIZE ? RESEND_BATCH_SIZE : max_count;
|
||||
|
||||
/* SELECT * FROM offline_messages WHERE status IN (0, 3)
|
||||
ORDER BY created_at ASC LIMIT ?; */
|
||||
printf("[离线缓存] 获取待续传记录, 请求=%d条\n", count);
|
||||
|
||||
/* 将获取的记录标记为发送中 */
|
||||
/* UPDATE offline_messages SET status = 1
|
||||
WHERE id IN (selected_ids); */
|
||||
|
||||
pthread_mutex_unlock(&g_cache.mutex);
|
||||
|
||||
/* 返回模拟获取数量 */
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* 更新缓存记录的发送状态
|
||||
*
|
||||
* @param record_id 记录ID
|
||||
* @param success 是否发送成功
|
||||
*/
|
||||
void offline_cache_update_status(int64_t record_id, bool success)
|
||||
{
|
||||
if (!g_cache.initialized) return;
|
||||
|
||||
pthread_mutex_lock(&g_cache.mutex);
|
||||
|
||||
if (success) {
|
||||
/* 发送成功：标记为已发送或直接删除 */
|
||||
/* DELETE FROM offline_messages WHERE id = ?; */
|
||||
g_cache.total_resent++;
|
||||
printf("[离线缓存] 记录 #%lld 续传成功, 累计=%lu\n",
|
||||
(long long)record_id, g_cache.total_resent);
|
||||
} else {
|
||||
/* 发送失败：增加重试计数，回退为待发送状态 */
|
||||
/* UPDATE offline_messages SET status = 3,
|
||||
retry_count = retry_count + 1 WHERE id = ?; */
|
||||
printf("[离线缓存] 记录 #%lld 续传失败，将重试\n",
|
||||
(long long)record_id);
|
||||
}
|
||||
|
||||
pthread_mutex_unlock(&g_cache.mutex);
|
||||
}
|
||||
|
||||
/**
|
||||
* 续传线程主函数
|
||||
* 网络恢复后持续将缓存数据发送至云端
|
||||
*/
|
||||
static void *resend_thread_func(void *arg)
|
||||
{
|
||||
printf("[离线缓存] 续传线程启动\n");
|
||||
|
||||
while (g_cache.initialized) {
|
||||
if (!g_cache.network_up) {
|
||||
/* 网络未恢复，休眠等待 */
|
||||
usleep(1000000); /* 1秒 */
|
||||
continue;
|
||||
}
|
||||
|
||||
cache_record_t records[RESEND_BATCH_SIZE];
|
||||
int count = offline_cache_fetch_pending(records, RESEND_BATCH_SIZE);
|
||||
|
||||
if (count == 0) {
|
||||
/* 无待续传数据，降低检查频率 */
|
||||
usleep(5000000); /* 5秒 */
|
||||
continue;
|
||||
}
|
||||
|
||||
/* 逐条发送 */
|
||||
for (int i = 0; i < count; i++) {
|
||||
/* 验证CRC完整性 */
|
||||
uint32_t calc_crc = calculate_crc32(records[i].payload,
|
||||
records[i].payload_len);
|
||||
if (calc_crc != records[i].crc32) {
|
||||
printf("[离线缓存] 记录 #%lld CRC校验失败, 丢弃\n",
|
||||
(long long)records[i].record_id);
|
||||
offline_cache_update_status(records[i].record_id, true);
|
||||
continue;
|
||||
}
|
||||
|
||||
/* 调用MQTT客户端发送 */
|
||||
/* int ret = mqtt_client_publish(records[i].mqtt_topic,
|
||||
records[i].payload, records[i].payload_len,
|
||||
records[i].qos); */
|
||||
int ret = 0; /* 模拟发送成功 */
|
||||
|
||||
offline_cache_update_status(records[i].record_id, (ret == 0));
|
||||
|
||||
/* 控制续传速率 */
|
||||
usleep(RESEND_INTERVAL_MS * 1000);
|
||||
}
|
||||
}
|
||||
|
||||
printf("[离线缓存] 续传线程退出\n");
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/**
|
||||
* 通知网络状态变更
|
||||
* 网络恢复时启动续传线程
|
||||
*/
|
||||
void offline_cache_set_network_state(bool network_up)
|
||||
{
|
||||
bool prev_state = g_cache.network_up;
|
||||
g_cache.network_up = network_up;
|
||||
|
||||
if (!prev_state && network_up) {
|
||||
/* 网络从断开恢复 -> 启动续传 */
|
||||
printf("[离线缓存] 网络恢复, 启动续传线程\n");
|
||||
if (!g_cache.resending) {
|
||||
g_cache.resending = true;
|
||||
pthread_create(&g_cache.resend_thread, NULL,
|
||||
resend_thread_func, NULL);
|
||||
}
|
||||
} else if (prev_state && !network_up) {
|
||||
printf("[离线缓存] 网络断开, 暂停续传\n");
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* 获取离线缓存统计信息
|
||||
*/
|
||||
void offline_cache_get_stats(uint64_t *cached, uint64_t *resent,
|
||||
uint64_t *evicted, uint64_t *current_bytes)
|
||||
{
|
||||
if (cached) *cached = g_cache.total_cached;
|
||||
if (resent) *resent = g_cache.total_resent;
|
||||
if (evicted) *evicted = g_cache.total_evicted;
|
||||
if (current_bytes) *current_bytes = g_cache.current_size;
|
||||
}
|
||||
|
||||
/**
|
||||
* 关闭离线缓存模块
|
||||
* 等待续传线程结束，关闭数据库
|
||||
*/
|
||||
void offline_cache_shutdown(void)
|
||||
{
|
||||
g_cache.initialized = false;
|
||||
|
||||
/* 等待续传线程退出 */
|
||||
if (g_cache.resending) {
|
||||
pthread_join(g_cache.resend_thread, NULL);
|
||||
g_cache.resending = false;
|
||||
}
|
||||
|
||||
/* 关闭数据库 */
|
||||
/* sqlite3_close(g_cache.db); */
|
||||
|
||||
pthread_mutex_destroy(&g_cache.mutex);
|
||||
|
||||
printf("[离线缓存] 已关闭, 累计缓存=%lu, 续传=%lu, 淘汰=%lu\n",
|
||||
g_cache.total_cached, g_cache.total_resent, g_cache.total_evicted);
|
||||
}
|
||||
Reference in New Issue
Block a user