feat(shorebird_cli): add cache (wip)

packages/shorebird_cli/lib/src/cache.dart

@@ -0,0 +1,117 @@
+import 'dart:io' hide Platform;
+import 'dart:isolate';
+
+import 'package:archive/archive_io.dart';
+import 'package:http/http.dart';
+import 'package:path/path.dart' as p;
+import 'package:platform/platform.dart';
+import 'package:shorebird_cli/src/engine_revision.dart';
+import 'package:shorebird_cli/src/shorebird_paths.dart';
+
+class Cache {
+  Cache({Platform platform = const LocalPlatform()}) {
+    registerArtifact(PatchArtifact(cache: this, platform: platform));
+  }
+
+  void registerArtifact(CachedArtifact artifact) => _artifacts.add(artifact);
+
+  Future<void> updateAll() async {
+    for (final artifact in _artifacts) {
+      if (await artifact.isUpToDate()) {
+        continue;
+      }
+
+      await artifact.download();
+    }
+  }
+
+  /// Get a named directory from with the cache's artifact directory;
+  /// for example, `foo` would return `bin/cache/artifacts/foo`.
+  Directory getArtifactDirectory(String name) {
+    return Directory(p.join(shorebirdArtifactsDirectory.path, name));
+  }
+
+  /// The Shorebird cached artifacts directory.
+  static Directory get shorebirdArtifactsDirectory => Directory(
+        p.join(
+          ShorebirdPaths.shorebirdCacheDirectory.path,
+          'artifacts',
+        ),
+      );
+
+  final List<CachedArtifact> _artifacts = [];
+
+  String get storageBaseUrl => 'https://storage.googleapis.com';
+
+  String get storageBucket => 'download.shorebird.dev';
+}
+
+abstract class CachedArtifact {
+  const CachedArtifact({required this.cache});
+
+  final Cache cache;
+
+  String get name;
+
+  String get storagePath;
+
+  List<String> get executables => [];
+
+  Directory get location => cache.getArtifactDirectory(name);
+
+  Future<bool> isUpToDate() async => location.existsSync();
+
+  Future<void> download() async {
+    final url = '${cache.storageBaseUrl}/${cache.storageBucket}/$storagePath';
+    final client = Client();
+    final request = Request('GET', Uri.parse(url));
+    final response = await client.send(request);
+    client.close();
+
+    final tempDir = Directory.systemTemp.createTempSync();
+    final archivePath = p.join(tempDir.path, '$name.zip');
+    await response.stream.pipe(File(archivePath).openWrite());
+
+    await Isolate.run(
+      () async {
+        final inputStream = InputFileStream(archivePath);
+        final archive = ZipDecoder().decodeBuffer(inputStream);
+        extractArchiveToDisk(archive, location.path);
+      },
+    );
+
+    for (final executable in executables) {
+      final process = await Process.start(
+        'chmod',
+        ['+x', p.join(location.path, executable)],
+      );
+      await process.exitCode;
+    }
+  }
+}
+
+class PatchArtifact extends CachedArtifact {
+  PatchArtifact({required super.cache, required this.platform});
+
+  final Platform platform;
+
+  @override
+  String get name => 'patch';
+
+  @override
+  List<String> get executables => ['patch'];
+
+  @override
+  String get storagePath {
+    var artifactName = 'patch-';
+    if (platform.isMacOS) {
+      artifactName += 'darwin-x64.zip';
+    } else if (platform.isLinux) {
+      artifactName += 'linux-x64.zip';
+    } else if (platform.isWindows) {
+      artifactName += 'windows-x64.zip';
+    }
+
+    return 'shorebird/$shorebirdEngineRevision/$artifactName';
+  }
+}

packages/shorebird_cli/lib/src/command.dart

@@ -6,6 +6,7 @@ import 'package:http/http.dart' as http;
 import 'package:mason_logger/mason_logger.dart';
 import 'package:meta/meta.dart';
 import 'package:shorebird_cli/src/auth/auth.dart';
+import 'package:shorebird_cli/src/cache.dart';
 import 'package:shorebird_cli/src/shorebird_process.dart';
 import 'package:shorebird_cli/src/validators/validators.dart';
 import 'package:shorebird_code_push_client/shorebird_code_push_client.dart';
@@ -28,11 +29,13 @@ abstract class ShorebirdCommand extends Command<int> {
   ShorebirdCommand({
     required this.logger,
     Auth? auth,
+    Cache? cache,
     CodePushClientBuilder? buildCodePushClient,
     RunProcess? runProcess,
     StartProcess? startProcess,
     ShorebirdFlutterValidator? flutterValidator,
   })  : auth = auth ?? Auth(),
+        cache = cache ?? Cache(),
         buildCodePushClient = buildCodePushClient ?? CodePushClient.new,
         runProcess = runProcess ?? ShorebirdProcess.run,
         startProcess = startProcess ?? ShorebirdProcess.start {
@@ -41,6 +44,7 @@ abstract class ShorebirdCommand extends Command<int> {
   }
 
   final Auth auth;
+  final Cache cache;
   final CodePushClientBuilder buildCodePushClient;
   final Logger logger;
   final RunProcess runProcess;

packages/shorebird_cli/lib/src/commands/patch_command.dart

@@ -107,6 +107,8 @@ class PatchCommand extends ShorebirdCommand
       return ExitCode.usage.code;
     }
 
+    await cache.updateAll();
+
     final buildProgress = logger.progress('Building patch');
     try {
       await buildRelease();
@@ -377,8 +379,10 @@ Please create a release using "shorebird release" and try again.
   }) async {
     final tempDir = await Directory.systemTemp.createTemp();
     final diffPath = p.join(tempDir.path, 'diff.patch');
-
-    final diffExecutable = p.join('patch');
+    final diffExecutable = p.join(
+      cache.getArtifactDirectory('patch').path,
+      'patch',
+    );
     final diffArguments = [
       releaseArtifactPath,
       patchArtifactPath,

packages/shorebird_cli/lib/src/shorebird_environment.dart

@@ -27,6 +27,11 @@ abstract class ShorebirdEnvironment {
         ),
       );
 
+  /// The Shorebird cache directory.
+  static Directory get shorebirdCacheDirectory => Directory(
+        p.join(shorebirdRoot.path, 'bin', 'cache'),
+      );
+
   /// The Shorebird-vended Flutter binary.
   static File get flutterBinaryFile => File(
         p.join(

packages/shorebird_code_push_client/lib/src/code_push_client.dart

@@ -1,6 +1,5 @@
 import 'dart:convert';
 import 'dart:io';
-import 'dart:typed_data';
 
 import 'package:http/http.dart' as http;
 import 'package:shorebird_code_push_protocol/shorebird_code_push_protocol.dart';