[flutter_tools] Use gzip level 1 for devfs transfer compression (#54123)

packages/flutter_tools/lib/src/base/io.dart

@@ -61,6 +61,7 @@ export 'dart:io'
         // File,              NO! Use `file_system.dart`
         // FileSystemEntity,  NO! Use `file_system.dart`
         gzip,
+        GZipCodec,
         HandshakeException,
         HttpClient,
         HttpClientRequest,

packages/flutter_tools/lib/src/base/os.dart

@@ -52,6 +52,9 @@ abstract class OperatingSystemUtils {
         processManager: processManager,
       );
 
+  @visibleForTesting
+  static final GZipCodec gzipLevel1 = GZipCodec(level: 1);
+
   final FileSystem _fileSystem;
   final Logger _logger;
   final Platform _platform;
@@ -98,6 +101,11 @@ abstract class OperatingSystemUtils {
   /// Returns true if the gzip is not corrupt (does not check tar).
   bool verifyGzip(File gzippedFile);
 
+  /// Compresses a stream using gzip level 1 (faster but larger).
+  Stream<List<int>> gzipLevel1Stream(Stream<List<int>> stream) {
+    return stream.cast<List<int>>().transform<List<int>>(gzipLevel1.encoder);
+  }
+
   /// Returns a pretty name string for the current operating system.
   ///
   /// If available, the detailed version of the OS is included.

packages/flutter_tools/lib/src/devfs.dart

@@ -12,6 +12,7 @@ import 'base/context.dart';
 import 'base/file_system.dart';
 import 'base/io.dart';
 import 'base/net.dart';
+import 'base/os.dart';
 import 'build_info.dart';
 import 'bundle.dart';
 import 'compile.dart';
@@ -46,8 +47,10 @@ abstract class DevFSContent {
 
   Stream<List<int>> contentsAsStream();
 
-  Stream<List<int>> contentsAsCompressedStream() {
-    return contentsAsStream().cast<List<int>>().transform<List<int>>(gzip.encoder);
+  Stream<List<int>> contentsAsCompressedStream(
+    OperatingSystemUtils osUtils,
+  ) {
+    return osUtils.gzipLevel1Stream(contentsAsStream());
   }
 
   /// Return the list of files this content depends on.
@@ -265,15 +268,21 @@ class DevFSException implements Exception {
 }
 
 class _DevFSHttpWriter {
-  _DevFSHttpWriter(this.fsName, VMService serviceProtocol)
+  _DevFSHttpWriter(
+    this.fsName,
+    VMService serviceProtocol, {
+    @required OperatingSystemUtils osUtils,
+  })
     : httpAddress = serviceProtocol.httpAddress,
       _client = (context.get<HttpClientFactory>() == null)
         ? HttpClient()
-        : context.get<HttpClientFactory>()();
+        : context.get<HttpClientFactory>()(),
+      _osUtils = osUtils;
 
   final String fsName;
   final Uri httpAddress;
   final HttpClient _client;
+  final OperatingSystemUtils _osUtils;
 
   static const int kMaxInFlight = 6;
 
@@ -312,7 +321,9 @@ class _DevFSHttpWriter {
         request.headers.removeAll(HttpHeaders.acceptEncodingHeader);
         request.headers.add('dev_fs_name', fsName);
         request.headers.add('dev_fs_uri_b64', base64.encode(utf8.encode('$deviceUri')));
-        final Stream<List<int>> contents = content.contentsAsCompressedStream();
+        final Stream<List<int>> contents = content.contentsAsCompressedStream(
+          _osUtils,
+        );
         await request.addStream(contents);
         final HttpClientResponse response = await request.close();
         response.listen((_) => null,
@@ -385,8 +396,13 @@ class DevFS {
     this.fsName,
     this.rootDirectory, {
     String packagesFilePath,
+    @required OperatingSystemUtils osUtils,
   }) : _operations = ServiceProtocolDevFSOperations(serviceProtocol),
-       _httpWriter = _DevFSHttpWriter(fsName, serviceProtocol),
+       _httpWriter = _DevFSHttpWriter(
+        fsName,
+        serviceProtocol,
+        osUtils: osUtils,
+      ),
        _packagesFilePath = packagesFilePath ?? globals.fs.path.join(rootDirectory.path, kPackagesFileName);
 
   DevFS.operations(

packages/flutter_tools/lib/src/resident_runner.dart

@@ -281,6 +281,7 @@ class FlutterDevice {
       fsName,
       rootDirectory,
       packagesFilePath: packagesFilePath,
+      osUtils: globals.os,
     );
     return devFS.create();
   }

packages/flutter_tools/test/general.shard/base/os_test.dart

@@ -86,6 +86,10 @@ void main() {
       expect(result[1].path, kPath2);
     });
   });
+
+  testWithoutContext('stream compression level', () {
+    expect(OperatingSystemUtils.gzipLevel1.level, equals(1));
+  });
 }
 
 class MockProcessManager extends Mock implements ProcessManager {}

packages/flutter_tools/test/general.shard/devfs_test.dart

@@ -11,6 +11,7 @@ import 'package:file/memory.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/io.dart';
 import 'package:flutter_tools/src/base/net.dart';
+import 'package:flutter_tools/src/base/os.dart';
 import 'package:flutter_tools/src/compile.dart';
 import 'package:flutter_tools/src/devfs.dart';
 import 'package:flutter_tools/src/vmservice.dart';
@@ -96,6 +97,7 @@ void main() {
   group('mocked http client', () {
     HttpOverrides savedHttpOverrides;
     HttpClient httpClient;
+    OperatingSystemUtils osUtils;
 
     setUpAll(() {
       tempDir = _newTempDir(fs);
@@ -103,6 +105,7 @@ void main() {
       savedHttpOverrides = HttpOverrides.current;
       httpClient = MockOddlyFailingHttpClient();
       HttpOverrides.global = MyHttpOverrides(httpClient);
+      osUtils = MockOperatingSystemUtils();
     });
 
     tearDownAll(() async {
@@ -147,7 +150,12 @@ void main() {
           return Future<HttpClientResponse>.value(httpClientResponse);
         });
 
-        final DevFS devFS = DevFS(vmService, 'test', tempDir);
+        final DevFS devFS = DevFS(
+          vmService,
+          'test',
+          tempDir,
+          osUtils: osUtils,
+        );
         await devFS.create();
 
         final MockResidentCompiler residentCompiler = MockResidentCompiler();
@@ -163,6 +171,7 @@ void main() {
         expect(report.success, isTrue);
         verify(httpClient.putUrl(any)).called(kFailedAttempts + 1);
         verify(httpRequest.close()).called(kFailedAttempts + 1);
+        verify(osUtils.gzipLevel1Stream(any)).called(kFailedAttempts + 1);
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
         HttpClientFactory: () => () => httpClient,
@@ -185,7 +194,12 @@ void main() {
 
     setUp(() {
       vmService.resetState();
-      devFS = DevFS(vmService, 'test', tempDir);
+      devFS = DevFS(
+        vmService,
+        'test',
+        tempDir,
+        osUtils: FakeOperatingSystemUtils(),
+      );
     });
 
     tearDownAll(() async {
@@ -477,3 +491,4 @@ class MockOddlyFailingHttpClient extends Mock implements HttpClient {}
 class MockHttpClientRequest extends Mock implements HttpClientRequest {}
 class MockHttpHeaders extends Mock implements HttpHeaders {}
 class MockHttpClientResponse extends Mock implements HttpClientResponse {}
+class MockOperatingSystemUtils extends Mock implements OperatingSystemUtils {}

packages/flutter_tools/test/src/context.dart

@@ -321,6 +321,9 @@ class FakeOperatingSystemUtils implements OperatingSystemUtils {
   @override
   bool verifyGzip(File gzippedFile) => true;
 
+  @override
+  Stream<List<int>> gzipLevel1Stream(Stream<List<int>> stream) => stream;
+
   @override
   String get name => 'fake OS name and version';