@sema-agent/core/dist/engine/session/log-digest.js

Stateless, task-oriented AI agent core

import { createHash } from "node:crypto";
export const SESSION_LOG_DIGEST_SCHEME = "sema-log-v3";
function wireForm(value, seen) {
    try {
        return JSON.parse(JSON.stringify(value) ?? "null");
    }
    catch {
    }
    if (value === null || typeof value !== "object")
        return { __sema_unserializable__: true };
    const guard = seen ?? new WeakSet();
    if (guard.has(value))
        return { __sema_unserializable__: true };
    guard.add(value);
    try {
        if (Array.isArray(value))
            return value.map((v) => wireForm(v, guard));
        const out = {};
        for (const k of Object.keys(value)) {
            try {
                out[k] = wireForm(value[k], guard);
            }
            catch {
                out[k] = { __sema_unserializable__: true };
            }
        }
        return out;
    }
    catch {
        return { __sema_unserializable__: true };
    }
    finally {
        guard.delete(value);
    }
}
function stableJson(v) {
    if (v === null || typeof v !== "object")
        return JSON.stringify(v) ?? "null";
    if (Array.isArray(v))
        return `[${v.map(stableJson).join(",")}]`;
    const o = v;
    return `{${Object.keys(o).sort().map((k) => `${JSON.stringify(k)}:${stableJson(o[k])}`).join(",")}}`;
}
export function sessionEntryDigest(entry) {
    return `${SESSION_LOG_DIGEST_SCHEME}:sha256:${createHash("sha256").update(`entry\n${stableJson(wireForm(entry))}`, "utf8").digest("hex")}`;
}
export function sessionLogDigest(entries) {
    const list = entries ?? [];
    if (!Array.isArray(list))
        throw new TypeError("sessionLogDigest expects an array of session entries (or null/undefined for an empty log)");
    const h = createHash("sha256");
    h.update(`${SESSION_LOG_DIGEST_SCHEME}\nlog\n${list.length}\n`, "utf8");
    for (const e of list) {
        const c = stableJson(wireForm(e));
        h.update(`${Buffer.byteLength(c, "utf8")}:`, "utf8");
        h.update(c, "utf8");
    }
    return `${SESSION_LOG_DIGEST_SCHEME}:sha256:${h.digest("hex")}`;
}
export function sessionLogDigestsComparable(a, b) {
    const wellFormed = (d) => typeof d === "string" && new RegExp(`^${SESSION_LOG_DIGEST_SCHEME}:sha256:[0-9a-f]{64}$`).test(d);
    return wellFormed(a) && wellFormed(b);
}