Use built-in library functions in preference to custom implementations

- Use built-in `hashFiles` function included in '@actions/globv0.2.0'
- Use `downloadTool` and `extractZip` functions from '@actions/tool-cache'

src/crypto-utils.ts

@@ -1,44 +1,13 @@
-import * as crypto from 'crypto'
-import * as fs from 'fs'
 import * as path from 'path'
-import * as stream from 'stream'
-import * as util from 'util'
-
 import * as glob from '@actions/glob'
 
 export async function hashFiles(
     baseDir: string,
-    globs: string[] = ['**'],
+    patterns: string[] = ['**'],
     followSymbolicLinks = false
 ): Promise<string | null> {
-    let hasMatch = false
-    type FileHashes = Record<string, Buffer>
-    const hashes: FileHashes = {}
-    for await (const globPattern of globs) {
-        const globMatch = `${baseDir}${path.sep}${globPattern}`
-        const globber = await glob.create(globMatch, {followSymbolicLinks})
-        for await (const file of globber.globGenerator()) {
-            // console.log(file)
-            if (!file.startsWith(`${baseDir}${path.sep}`)) {
-                // console.log(`Ignore '${file}' since it is not under '${baseDir}'.`)
-                continue
-            }
-            if (fs.statSync(file).isDirectory()) {
-                // console.log(`Skip directory '${file}'.`)
-                continue
-            }
-            const hash = crypto.createHash('sha256')
-            const pipeline = util.promisify(stream.pipeline)
-            await pipeline(fs.createReadStream(file), hash)
-            hashes[path.relative(baseDir, file)] = hash.digest()
-            hasMatch = true
-        }
-    }
-    if (!hasMatch) return null
-    const result = crypto.createHash('sha256')
-    for (const file of Object.keys(hashes).sort()) {
-        result.update(hashes[file])
-    }
-    result.end()
-    return result.digest('hex')
+    const combinedPatterns = patterns
+        .map(pattern => `${baseDir}${path.sep}${pattern}`)
+        .join('\n')
+    return glob.hashFiles(combinedPatterns, {followSymbolicLinks})
 }