puppeteer/tools/internal/job.ts
2023-02-15 15:09:31 -08:00

154 lines
3.4 KiB
TypeScript

import {createHash} from 'crypto';
import {existsSync, Stats} from 'fs';
import {mkdir, readFile, stat, writeFile} from 'fs/promises';
import {tmpdir} from 'os';
import {dirname, join} from 'path';
import {glob} from 'glob';
interface JobContext {
name: string;
inputs: string[];
outputs: string[];
}
class JobBuilder {
#inputs: string[] = [];
#outputs: string[] = [];
#callback: (ctx: JobContext) => Promise<void>;
#name: string;
#value = '';
#force = false;
constructor(name: string, callback: (ctx: JobContext) => Promise<void>) {
this.#name = name;
this.#callback = callback;
}
get jobHash(): string {
return createHash('sha256').update(this.#name).digest('hex');
}
force() {
this.#force = true;
return this;
}
value(value: string) {
this.#value = value;
return this;
}
inputs(inputs: string[]): JobBuilder {
this.#inputs = inputs.flatMap(value => {
if (glob.hasMagic(value)) {
return glob.sync(value);
}
return value;
});
return this;
}
outputs(outputs: string[]): JobBuilder {
if (!this.#name) {
this.#name = outputs.join(' and ');
}
this.#outputs = outputs;
return this;
}
async build(): Promise<void> {
console.log(`Running job ${this.#name}...`);
// For debugging.
if (this.#force) {
return this.#run();
}
// In case we deleted an output file on purpose.
if (!this.getOutputStats()) {
return this.#run();
}
// Run if the job has a value, but it changes.
if (this.#value) {
if (!(await this.isValueDifferent())) {
return;
}
return this.#run();
}
// Always run when there is no output.
if (!this.#outputs.length) {
return this.#run();
}
// Make-like comparator.
if (!(await this.areInputsNewer())) {
return;
}
return this.#run();
}
async isValueDifferent(): Promise<boolean> {
const file = join(tmpdir(), `puppeteer/${this.jobHash}.txt`);
await mkdir(dirname(file), {recursive: true});
if (!existsSync(file)) {
await writeFile(file, this.#value);
return true;
}
return this.#value !== (await readFile(file, 'utf8'));
}
#outputStats?: Stats[];
async getOutputStats(): Promise<Stats[] | undefined> {
if (this.#outputStats) {
return this.#outputStats;
}
try {
this.#outputStats = await Promise.all(
this.#outputs.map(output => {
return stat(output);
})
);
} catch {}
return this.#outputStats;
}
async areInputsNewer(): Promise<boolean> {
const inputStats = await Promise.all(
this.#inputs.map(input => {
return stat(input);
})
);
const outputStats = await this.getOutputStats();
if (
outputStats &&
outputStats.reduce(reduceMinTime, Infinity) >
inputStats.reduce(reduceMaxTime, 0)
) {
return false;
}
return true;
}
#run(): Promise<void> {
return this.#callback({
name: this.#name,
inputs: this.#inputs,
outputs: this.#outputs,
});
}
}
export const job = (
name: string,
callback: (ctx: JobContext) => Promise<void>
): JobBuilder => {
return new JobBuilder(name, callback);
};
const reduceMaxTime = (time: number, stat: Stats) => {
return time < stat.mtimeMs ? stat.mtimeMs : time;
};
const reduceMinTime = (time: number, stat: Stats) => {
return time > stat.mtimeMs ? stat.mtimeMs : time;
};