193 lines
6.1 KiB
TypeScript
193 lines
6.1 KiB
TypeScript
import assert from 'assert';
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import { v4, v1, stringify } from 'uuid';
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import { getRandomValues } from './random/random';
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let _nodeId: number[];
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let _clockseq: number;
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// Previous uuid creation time
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let _lastMSecs = 0;
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let _lastNSecs = 0;
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// 根据uuid v1改的，产生按时间顺序uuid的函数（更优于底层数据库的插入行为）
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// **`v1()` - Generate time-based UUID**
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//
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// Inspired by https://github.com/LiosK/UUID.js
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// and http://docs.python.org/library/uuid.html
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const byteToHex: string[] = [];
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for (let i = 0; i < 256; ++i) {
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byteToHex.push((i + 0x100).toString(16).slice(1));
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}
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function unsafeStringify(arr: number[], offset = 0) {
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// Note: Be careful editing this code! It's been tuned for performance
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// and works in ways you may not expect. See https://github.com/uuidjs/uuid/pull/434
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return (byteToHex[arr[offset + 0]] + byteToHex[arr[offset + 1]] + byteToHex[arr[offset + 2]] + byteToHex[arr[offset + 3]] + '-' + byteToHex[arr[offset + 4]] + byteToHex[arr[offset + 5]] + '-' + byteToHex[arr[offset + 6]] + byteToHex[arr[offset + 7]] + '-' + byteToHex[arr[offset + 8]] + byteToHex[arr[offset + 9]] + '-' + byteToHex[arr[offset + 10]] + byteToHex[arr[offset + 11]] + byteToHex[arr[offset + 12]] + byteToHex[arr[offset + 13]] + byteToHex[arr[offset + 14]] + byteToHex[arr[offset + 15]]).toLowerCase();
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}
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// See https://github.com/uuidjs/uuid for API details
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export function sequentialUuid({ random }: { random: Uint8Array }) {
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let i = 0;
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const b = new Array(16);
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let node = _nodeId;
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let clockseq = _clockseq;
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// node and clockseq need to be initialized to random values if they're not
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// specified. We do this lazily to minimize issues related to insufficient
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// system entropy. See #189
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if (node == null || clockseq == null) {
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const seedBytes = random;
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if (node == null) {
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// Per 4.5, create and 48-bit node id, (47 random bits + multicast bit = 1)
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node = _nodeId = [
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seedBytes[0] | 0x01,
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seedBytes[1],
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seedBytes[2],
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seedBytes[3],
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seedBytes[4],
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seedBytes[5],
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];
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}
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if (clockseq == null) {
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// Per 4.2.2, randomize (14 bit) clockseq
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clockseq = _clockseq = ((seedBytes[6] << 8) | seedBytes[7]) & 0x3fff;
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}
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}
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// UUID timestamps are 100 nano-second units since the Gregorian epoch,
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// (1582-10-15 00:00). JSNumbers aren't precise enough for this, so
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// time is handled internally as 'msecs' (integer milliseconds) and 'nsecs'
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// (100-nanoseconds offset from msecs) since unix epoch, 1970-01-01 00:00.
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let msecs = Date.now();
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// Per 4.2.1.2, use count of uuid's generated during the current clock
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// cycle to simulate higher resolution clock
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let nsecs = _lastNSecs + 1;
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// Time since last uuid creation (in msecs)
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const dt = msecs - _lastMSecs + (nsecs - _lastNSecs) / 10000;
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// Per 4.2.1.2, Bump clockseq on clock regression
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if (dt < 0) {
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clockseq = (clockseq + 1) & 0x3fff;
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}
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// Reset nsecs if clock regresses (new clockseq) or we've moved onto a new
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// time interval
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if ((dt < 0 || msecs > _lastMSecs)) {
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nsecs = 0;
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}
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// Per 4.2.1.2 Throw error if too many uuids are requested
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if (nsecs >= 10000) {
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throw new Error("uuid.v1(): Can't create more than 10M uuids/sec");
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}
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_lastMSecs = msecs;
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_lastNSecs = nsecs;
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_clockseq = clockseq;
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// Per 4.1.4 - Convert from unix epoch to Gregorian epoch
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msecs += 12219292800000;
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// `time_high_and_version`
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const tmh = ((msecs / 0x100000000) * 10000) & 0xfffffff;
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b[i++] = ((tmh >>> 24) & 0xf) | 0x10; // include version
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b[i++] = (tmh >>> 16) & 0xff;
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// `time_mid`
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b[i++] = (tmh >>> 8) & 0xff;
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b[i++] = tmh & 0xff;
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// `time_low`
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const tl = ((msecs & 0xfffffff) * 10000 + nsecs) % 0x100000000;
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b[i++] = (tl >>> 24) & 0xff;
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b[i++] = (tl >>> 16) & 0xff;
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b[i++] = (tl >>> 8) & 0xff;
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b[i++] = tl & 0xff;
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// `clock_seq_hi_and_reserved` (Per 4.2.2 - include variant)
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b[i++] = (clockseq >>> 8) | 0x80;
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// `clock_seq_low`
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b[i++] = clockseq & 0xff;
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// `node`
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for (let n = 0; n < 6; ++n) {
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b[i + n] = node[n];
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}
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return unsafeStringify(b);
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}
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export function shrinkUuidTo32Bytes(uuid: string) {
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return uuid.replace(/\-/g, '');
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}
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export function expandUuidTo36Bytes(uuidShrinked: string) {
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return `${uuidShrinked.slice(0, 8)}-${uuidShrinked.slice(8, 12)}-${uuidShrinked.slice(12, 16)}-${uuidShrinked.slice(16, 20)}-${uuidShrinked.slice(20)}`;
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}
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export type GenerateIdOption = {
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shuffle?: boolean;
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};
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// 直接生成uuid的接口，为了适配各种环境，写成异步
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export async function generateNewIdAsync(option?: GenerateIdOption) {
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const option2 = option || ID_OPTION;
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if (option2?.shuffle || process.env.NODE_ENV === 'development') {
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return v4({ random: await getRandomValues(16) });
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}
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return sequentialUuid({ random: await getRandomValues(16) });
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}
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// 实现同步的id缓存接口，以便于前台使用
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const ID_BUFFER: string[] = [];
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let ID_OPTION: GenerateIdOption = {
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};
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export async function produceIds() {
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let iter = 0;
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for (; iter < 128; iter++) {
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ID_BUFFER.push(await generateNewIdAsync());
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}
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}
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produceIds();
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export function setGenerateIdOption(option: GenerateIdOption) {
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ID_OPTION = option;
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ID_BUFFER.splice(0, ID_BUFFER.length);
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return produceIds();
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}
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export function generateNewId() {
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if (ID_BUFFER.length > 0) {
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const id = ID_BUFFER.pop()!;
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if (ID_BUFFER.length < 64) {
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produceIds();
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}
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return id;
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}
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else {
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// 如果没来的及填满缓冲池，这里用一个简单的算法产生同步id（在小程序环境下跑出来过）
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const random = new Uint8Array(16);
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let iter = 0;
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do {
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random[iter] = Math.ceil(Math.random() * 1000) % 128;
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} while (++iter < 16);
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if (ID_OPTION?.shuffle || process.env.NODE_ENV === 'development') {
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return v4({ random });
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}
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return sequentialUuid({ random });
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}
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}
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