feat(core): add native extension implementation

This reverts commit b30c9fd.

packages/nx/src/hasher/file-hasher.ts

@@ -5,13 +5,18 @@ import { FileHasherBase } from './file-hasher-base';
 import { execSync } from 'child_process';
 import { existsSync } from 'fs';
 import { join } from 'path';
+import { NativeFileHasher } from './native-file-hasher';
 
 function createFileHasher(): FileHasherBase {
   // special case for unit tests
   if (workspaceRoot === '/root') {
     return new NodeBasedFileHasher();
   }
   try {
+    if (process.env.NX_NATIVE_HASHER) {
+      return new NativeFileHasher();
+    }
+
     execSync('git rev-parse --is-inside-work-tree', { stdio: 'ignore' });
     // we don't use git based hasher when the repo uses git submodules
     if (!existsSync(join(workspaceRoot, '.git', 'modules'))) {

packages/nx/src/hasher/native-file-hasher.ts

@@ -0,0 +1,34 @@
+import { FileHasherBase } from './file-hasher-base';
+import { performance } from 'perf_hooks';
+import { hashFile, hashFiles } from '@nrwl/native-extensions';
+import { workspaceRoot } from '../utils/app-root';
+
+export class NativeFileHasher extends FileHasherBase {
+  async init(): Promise<void> {
+    performance.mark('init hashing:start');
+    this.clear();
+    const filesObject = hashFiles(workspaceRoot);
+    this.fileHashes = new Map(Object.entries(filesObject));
+
+    performance.mark('init hashing:end');
+    performance.measure(
+      'init hashing',
+      'init hashing:start',
+      'init hashing:end'
+    );
+  }
+
+  async hashFiles(files: string[]): Promise<Map<string, string>> {
+    const r = new Map<string, string>();
+
+    for (let f of files) {
+      r.set(f, this.hashFile(f));
+    }
+
+    return r;
+  }
+
+  hashFile(path: string): string {
+    return hashFile(path).hash;
+  }
+}