53 lines
2.1 KiB
TypeScript
53 lines
2.1 KiB
TypeScript
import { appendFileSync, existsSync, readFileSync } from "node:fs";
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import { join } from "node:path";
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import { DatabaseSync } from "node:sqlite";
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import type { ChildProcess } from "node:child_process";
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import { sleep } from "./study.ts";
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// 账本里没有时间戳，墙钟时间由检验自己记：研究进程跑着的时候每隔一会儿看一眼账本，
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// 新出现的每条记录记下"第一次看到它的时刻"，写成 timeline.jsonl（每行 {seq, kind, at}，at 是毫秒）。
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// 只读打开账本、只查序号和种类，不经 Ledger.records()（那会每次重读、重查全部内容）。
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// 时刻比真实写入晚最多一个间隔，用来算阶段级的墙钟足够。
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const POLL_MS = 1000;
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export interface TimelineRow {
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seq: number;
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kind: string;
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at: number;
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}
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/** 已经记下的最大序号；文件还没有就是 0。接着跑时往同一个文件后面追加。 */
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function lastSeq(file: string): number {
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if (!existsSync(file)) return 0;
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return readTimeline(file).reduce((m, r) => Math.max(m, r.seq), 0);
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}
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/** 研究进程退出前一直记；进程退出后再看最后一眼。调用前要先等 waitForLedger（表建好了才能读）。 */
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export async function watchTimeline(studyDir: string, child: ChildProcess, file: string): Promise<void> {
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let seen = lastSeq(file);
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const look = () => {
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const db = new DatabaseSync(join(studyDir, "ledger.sqlite"), { readOnly: true });
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try {
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const rows = db.prepare("SELECT seq, kind FROM records WHERE seq > ? ORDER BY seq").all(seen) as Array<{ seq: number; kind: string }>;
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const at = Date.now();
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for (const r of rows) appendFileSync(file, `${JSON.stringify({ seq: r.seq, kind: r.kind, at })}\n`);
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if (rows.length > 0) seen = rows.at(-1)!.seq;
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} finally {
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db.close();
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}
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};
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while (child.exitCode === null && child.signalCode === null) {
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look();
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await sleep(POLL_MS);
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}
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look();
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}
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export function readTimeline(file: string): TimelineRow[] {
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return readFileSync(file, "utf8")
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.split("\n")
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.filter((l) => l !== "")
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.map((l) => JSON.parse(l) as TimelineRow);
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}
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