electron/script/generate-deps-hash.js

const crypto = require('crypto')
const fs = require('fs')
const path = require('path')

// Fallback to blow away old cache keys
const HASH_VERSION = 1

// Base files to hash
const filesToHash = [
  path.resolve(__dirname, '../DEPS'),
  path.resolve(__dirname, '../yarn.lock'),
  path.resolve(__dirname, '../script/external-binaries.json'),
  path.resolve(__dirname, '../script/sysroots.json')
]

const addAllFiles = (dir) => {
  for (const child of fs.readdirSync(dir).sort()) {
    const childPath = path.resolve(dir, child)
    if (fs.statSync(childPath).isDirectory()) {
      addAllFiles(childPath)
    } else {
      filesToHash.push(childPath)
    }
  }
}

// Add all patch files to the hash
addAllFiles(path.resolve(__dirname, '../patches'))

// Create Hash
const hasher = crypto.createHash('SHA256')
hasher.update(`HASH_VERSION:${HASH_VERSION}`)
for (const file of filesToHash) {
  hasher.update(fs.readFileSync(file))
}

// Add the GCLIENT_EXTRA_ARGS variable to the hash
const extraArgs = process.env.GCLIENT_EXTRA_ARGS || 'no_extra_args'
hasher.update(extraArgs)

const effectivePlatform = extraArgs.includes('host_os=mac') ? 'darwin' : process.platform

// Write the hash to disk
fs.writeFileSync(path.resolve(__dirname, '../.depshash'), hasher.digest('hex'))

let targetContent = `${effectivePlatform}\n${process.env.TARGET_ARCH}\n${process.env.GN_CONFIG}\n${undefined}\n${process.env.GN_EXTRA_ARGS}\n${process.env.GN_BUILDFLAG_ARGS}`
const argsDir = path.resolve(__dirname, '../build/args')
for (const argFile of fs.readdirSync(argsDir).sort()) {
  targetContent += `\n${argFile}--${crypto.createHash('SHA1').update(fs.readFileSync(path.resolve(argsDir, argFile))).digest('hex')}`
}

fs.writeFileSync(path.resolve(__dirname, '../.depshash-target'), targetContent)