Worker + compression cleanups (#5602)

Author: canova

src/test/fixtures/node-worker.ts

@@ -23,6 +23,7 @@ function getWorkerScript(file: string): string {
       onmessage: function () {},
       DecompressionStream,
       CompressionStream,
+      Response,
     };
 
     vm.runInNewContext(scriptContent, sandbox, { filename: "${file}" });

src/test/setup.ts

@@ -25,8 +25,8 @@ fetchMock.mockGlobal();
 (global as any).fetchMock = fetchMock;
 
 // Mock the effects of the file-loader which our Webpack config defines
-// for JS files under res: The "default export" is the path to the file.
-jest.mock('firefox-profiler-res/gz-worker.js', () => './res/gz-worker.js');
+// for files ending in .worker.js: The "default export" is the path to the file.
+jest.mock('../utils/gz.worker.js', () => 'src/utils/gz.worker.js');
 
 // Install a Worker class which is similar to the DOM Worker class.
 (global as any).Worker = NodeWorker;

src/types/globals/global.d.ts

@@ -5,7 +5,7 @@
 // Added by webpack's DefinePlugin
 declare const AVAILABLE_STAGING_LOCALES: string[] | null;
 
-declare module 'firefox-profiler-res/*.js' {
+declare module '*.worker.js' {
   const content: string;
   export default content;
 }

src/utils/gz.ts

@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-import gzWorkerPath from 'firefox-profiler-res/gz-worker.js';
+import gzWorkerPath from './gz.worker.js';
 
 function runGzWorker(
   kind: 'compress' | 'decompress',
@@ -34,12 +34,45 @@ export async function compress(
   // Encode the data if it's a string
   const arrayData =
     typeof data === 'string' ? new TextEncoder().encode(data) : data;
+
+  if (!(typeof window === 'object' && 'Worker' in window)) {
+    // Try to fall back to Node's zlib library.
+    const zlib = await import('zlib');
+    return new Promise((resolve, reject) => {
+      zlib.gzip(data, (errorOrNull, result) => {
+        if (errorOrNull) {
+          reject(errorOrNull);
+        } else {
+          resolve(new Uint8Array(result.buffer as ArrayBuffer));
+        }
+      });
+    });
+  }
+
   return runGzWorker('compress', arrayData);
 }
 
 export async function decompress(
   data: Uint8Array<ArrayBuffer>
 ): Promise<Uint8Array<ArrayBuffer>> {
+  if (!(typeof window === 'object' && 'Worker' in window)) {
+    // Handle the case where we're not running in the browser, e.g. when
+    // this code is used as part of a library in a Node project.
+    // We don't get here when running Firefox profiler tests, because our
+    // tests create a mock window with a mock Worker class.
+    // Try to fall back to Node's zlib library.
+    const zlib = await import('zlib');
+    return new Promise((resolve, reject) => {
+      zlib.gunzip(data, (errorOrNull, result) => {
+        if (errorOrNull) {
+          reject(errorOrNull);
+        } else {
+          resolve(new Uint8Array(result.buffer as ArrayBuffer));
+        }
+      });
+    });
+  }
+
   return runGzWorker('decompress', data);
 }
 

res/gz-worker.js src/utils/gz.worker.jsres/gz-worker.js renamed to src/utils/gz.worker.js

@@ -3,35 +3,11 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 async function readableStreamToBuffer(stream) {
-  const reader = stream.getReader();
-  const chunks = [];
-
-  try {
-    while (true) {
-      const { done, value } = await reader.read();
-      if (done) break;
-      if (value) {
-        chunks.push(value);
-      }
-    }
-  } finally {
-    reader.releaseLock();
-  }
-
-  // Calculate total length and combine chunks
-  const totalLength = chunks.reduce((sum, chunk) => sum + chunk.length, 0);
-  const result = new Uint8Array(totalLength);
-  let offset = 0;
-  for (const chunk of chunks) {
-    result.set(chunk, offset);
-    offset += chunk.length;
-  }
-
-  return result;
+  return new Uint8Array(await new Response(stream).arrayBuffer());
 }
 
 onmessage = async (e) => {
-  let data = e.data;
+  const data = e.data;
   if (data.kind === 'compress') {
     // Create a gzip compression stream
     const compressionStream = new CompressionStream('gzip');
@@ -42,7 +18,7 @@ onmessage = async (e) => {
     writer.close();
 
     // Read the compressed data back into a buffer
-    let result = await readableStreamToBuffer(compressionStream.readable);
+    const result = await readableStreamToBuffer(compressionStream.readable);
     postMessage(result, [result.buffer]);
   } else if (data.kind === 'decompress') {
     // Create a gzip compression stream
@@ -54,7 +30,7 @@ onmessage = async (e) => {
     writer.close();
 
     // Read the compressed data back into a buffer
-    let result = await readableStreamToBuffer(decompressionStream.readable);
+    const result = await readableStreamToBuffer(decompressionStream.readable);
     postMessage(result, [result.buffer]);
   } else {
     throw new Error('unknown message');

webpack.config.js

@@ -32,15 +32,15 @@ const config = {
   devtool: 'source-map',
   module: {
     rules: [
-      {
-        test: /\.js$/,
-        use: ['file-loader'],
-        include: [path.join(__dirname, 'res')],
-      },
       {
         test: /\.(js|ts|tsx)$/,
         use: ['babel-loader'],
-        include: [path.join(__dirname, 'src')],
+        include: includes,
+      },
+      {
+        test: /\.worker\.js$/,
+        use: ['file-loader'],
+        include: includes,
       },
       {
         test: /\.json$/,
@@ -99,7 +99,6 @@ const config = {
       patterns: [
         'res/_headers',
         'res/_redirects',
-        'res/gz-worker.js',
         'res/contribute.json',
         'res/robots.txt',
         'res/service-worker-compat.js',