feat: 足迹 Footprints 个人留痕系统

桌面应用(Tauri+React+SQLite)：时间线/记录/学年学科成绩梯度/统计/类型与字段模板/附件内容寻址/详情视图/PWA 同步服务端(sync-server)：多用户+邀请码/LWW推拉/seq游标/附件去重/Docker部署多端同步地基：uuid v7/HLC混合逻辑时钟/软删除墓碑/sync_oplog，Node与Rust双端一致并通过自动化测试
2026-10-16 13:53:15 +08:00
commit 42ca57abfd
107 changed files with 234676 additions and 0 deletions
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+// 同步核心：push（LWW 仲裁）+ pull（seq 游标增量）
+import { getDb, SYNC_TABLES } from './db.mjs';
+
+function parseHlc(h) {
+  const m = /^([0-9]+):([0-9]+):(.+)$/.exec(String(h || ''));
+  if (!m) return null;
+  return { ms: Number(m[1]), cnt: Number(m[2]), dev: m[3] };
+}
+
+// a 是否严格新于 b：比较 (ms, cnt, dev)
+function isNewer(a, b) {
+  if (a.ms !== b.ms) return a.ms > b.ms;
+  if (a.cnt !== b.cnt) return a.cnt > b.cnt;
+  return a.dev > b.dev;
+}
+
+export function push(user_id, changes) {
+  const d = getDb();
+  const stats = { accepted: 0, stale: 0, invalid: 0 };
+  if (!Array.isArray(changes)) throw new Error('changes 必须为数组');
+  if (changes.length > 5000) throw new Error('单次推送不得超过 5000 条');
+
+  for (const c of changes) {
+    const table = c.table;
+    const row_uuid = String(c.row_uuid || '');
+    const op = c.op;
+    const parsed = parseHlc(c.hlc);
+    if (!SYNC_TABLES.has(table) || !parsed || !['upsert', 'delete'].includes(op)) {
+      stats.invalid++;
+      continue;
+    }
+    if (op === 'upsert' && (c.data == null || typeof c.data !== 'object')) {
+      stats.invalid++;
+      continue;
+    }
+    const dataJson = op === 'upsert' ? JSON.stringify(c.data) : null;
+
+    const existing = d.prepare(
+      'SELECT ms, cnt, dev FROM current WHERE user_id=? AND table_name=? AND row_uuid=?'
+    ).get(user_id, table, row_uuid);
+
+    if (existing) {
+      const e = { ms: existing.ms, cnt: existing.cnt, dev: existing.dev };
+      if (parsed.ms === e.ms && parsed.cnt === e.cnt && parsed.dev === e.dev) {
+        stats.accepted++; // 同一变更重放，幂等
+        continue;
+      }
+      if (!isNewer(parsed, e)) { stats.stale++; continue; }
+      d.prepare(`UPDATE current SET op=?, hlc=?, ms=?, cnt=?, dev=?, data=?,
+        updated_seq=(SELECT COALESCE(MAX(seq),0)+1 FROM changes) WHERE user_id=? AND table_name=? AND row_uuid=?`)
+        .run(op, c.hlc, parsed.ms, parsed.cnt, parsed.dev, dataJson, user_id, table, row_uuid);
+      d.prepare('INSERT INTO changes (user_id, table_name, row_uuid, op, hlc, data) VALUES (?,?,?,?,?,?)')
+        .run(user_id, table, row_uuid, op, c.hlc, dataJson);
+      stats.accepted++;
+    } else {
+      d.prepare(`INSERT INTO current (user_id, table_name, row_uuid, op, hlc, ms, cnt, dev, data,
+        updated_seq) VALUES (?,?,?,?,?,?,?,?,?,(SELECT COALESCE(MAX(seq),0)+1 FROM changes))`)
+        .run(user_id, table, row_uuid, op, c.hlc, parsed.ms, parsed.cnt, parsed.dev, dataJson);
+      d.prepare('INSERT INTO changes (user_id, table_name, row_uuid, op, hlc, data) VALUES (?,?,?,?,?,?)')
+        .run(user_id, table, row_uuid, op, c.hlc, dataJson);
+      stats.accepted++;
+    }
+  }
+  return stats;
+}
+
+export function pull(user_id, cursorRaw, limitRaw) {
+  const d = getDb();
+  const cursor = Math.max(0, Number(cursorRaw) || 0);
+  const limit = Math.min(2000, Math.max(1, Number(limitRaw) || 1000));
+  const rows = d.prepare(
+    'SELECT updated_seq AS seq, table_name, row_uuid, op, hlc, data FROM current WHERE user_id=? AND updated_seq > ? ORDER BY seq LIMIT ?'
+  ).all(user_id, cursor, limit);
+  const changes = rows.map(r => ({
+    seq: r.seq,
+    table: r.table_name,
+    row_uuid: r.row_uuid,
+    op: r.op,
+    hlc: r.hlc,
+    data: r.data ? JSON.parse(r.data) : null
+  }));
+  const maxSeqRow = d.prepare('SELECT COALESCE(MAX(updated_seq),0) AS m FROM current WHERE user_id=?').get(user_id);
+  const hasMore = rows.length === limit;
+  return {
+    changes,
+    cursor: hasMore ? rows[rows.length - 1].seq : Math.max(cursor, maxSeqRow.m),
+    has_more: hasMore
+  };
+}