add a protoc_plugin:generate CLI

benchmarks/tool/compile_protos.sh

@@ -4,26 +4,6 @@
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
-SCRIPT_DIR=$(dirname "${BASH_SOURCE}")
-BENCHMARK_DIR=$SCRIPT_DIR/..
-
-# These protos don't have any imports
-SIMPLE_PROTOS=(
-    "protos/google_message1_proto2.proto"
-    "protos/google_message1_proto3.proto"
-    "protos/google_message2.proto"
-    "protos/packed_fields.proto"
-)
-
-set -x
-set -e
-
-mkdir -p lib/generated
-
-protoc --dart_out=lib/generated --plugin=protoc-gen-dart=tool/run_protoc_plugin.sh \
-    -I$BENCHMARK_DIR/protos \
-    "${SIMPLE_PROTOS[@]/#/$BENCHMARK_DIR/}"
-
-protoc --dart_out=lib/generated --plugin=protoc-gen-dart=tool/run_protoc_plugin.sh \
-    -I$BENCHMARK_DIR/protos/query_benchmark \
-    $BENCHMARK_DIR/protos/query_benchmark/*.proto
+dart run protoc_plugin:generate \
+  --proto-path=protos/query_benchmark \
+  --out=lib/generated

protoc_plugin/Makefile

@@ -82,17 +82,13 @@ PREGENERATED_SRCS := $(shell find protos -name '*.proto')
 $(TEST_PROTO_LIBS): $(PLUGIN_SRC) $(TEST_PROTO_SRCS)
 	mkdir -p $(TEST_PROTO_DIR)
 
-	protoc\
-		--dart_out="$(TEST_PROTO_DIR)"\
-		-I$(TEST_PROTO_SRC_DIR)\
-		-Iprotos\
-		--plugin=protoc-gen-dart=$(realpath $(PLUGIN_PATH))\
+	dart run protoc_plugin:generate \
+	  --out="$(TEST_PROTO_DIR)" \
+		--proto-path=$(TEST_PROTO_SRC_DIR) \
 		$(TEST_PROTO_SRCS)
 
 update-pregenerated: $(PLUGIN_PATH) $(PREGENERATED_SRCS)
-	protoc --dart_out=lib/src/gen \
-		-Iprotos \
-		--plugin=protoc-gen-dart=$(realpath $(PLUGIN_PATH)) $(PREGENERATED_SRCS)
+	dart run protoc_plugin:generate
 	find lib/src/gen -name '*.pbjson.dart' -delete
 
 protos: $(PLUGIN_PATH) $(TEST_PROTO_LIBS)

protoc_plugin/bin/generate.dart

@@ -0,0 +1,14 @@
+#!/usr/bin/env dart
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// A command line utility to allow easy generation of protobuf files.
+library;
+
+import 'package:protoc_plugin/generate.dart';
+
+void main(List<String> args) {
+  final generator = ProtoGen();
+  generator.generate(args);
+}

protoc_plugin/bin/protoc_plugin.dart

@@ -3,10 +3,21 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+/// This entry-point is expected to be called from the `protoc` command-line
+/// tool.
+///
+/// It will read it's binary, protobuf encoded input from stdin and write its
+/// cooresponding output to stdout.
+///
+/// See https://protobuf.dev/reference/other/ for more information about
+/// Protobuf compiler plugins.
+library;
+
 import 'dart:io';
 
 import 'package:protoc_plugin/protoc.dart';
 
-void main() {
-  CodeGenerator(stdin, stdout).generate();
+void main() async {
+  final generator = CodeGenerator(stdin, stdout);
+  await generator.generate();
 }

protoc_plugin/bin/protoc_plugin_bazel.dart

@@ -8,9 +8,10 @@ import 'dart:io';
 import 'package:protoc_plugin/bazel.dart';
 import 'package:protoc_plugin/protoc.dart';
 
-void main() {
+void main() async {
   final packages = <String, BazelPackage>{};
-  CodeGenerator(stdin, stdout).generate(
+  final generator = CodeGenerator(stdin, stdout);
+  await generator.generate(
     optionParsers: {bazelOptionId: BazelOptionParser(packages)},
     config: BazelOutputConfiguration(packages),
   );

protoc_plugin/lib/generate.dart

@@ -0,0 +1,220 @@
+#!/usr/bin/env dart
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// A command line utility to allow easy generation of protobuf files.
+library;
+
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:args/args.dart';
+
+import 'src/generate_utils.dart';
+
+// TODO: update readme docs
+
+// TODO: review the UI here
+
+// TODO: have an option to not include defaults
+
+// TODO: generate grpc by default?
+
+// TODO: add tests
+
+class ProtoGen {
+  void generate(List<String> args) {
+    final parser = _createArgParser();
+
+    ArgResults results;
+
+    try {
+      results = parser.parse(args);
+    } on ArgParserException catch (e) {
+      _usage(e.message, parser, isFailure: true);
+    }
+
+    if (results.flag('help')) {
+      _usage(
+        'A wrapper around protoc to make it easier to generate Dart code from '
+        'protobuf definitions.',
+        parser,
+      );
+    }
+
+    final out = results.option('out');
+    final version = results.flag('version');
+    final grpc = results.flag('grpc');
+    final protoPaths = results.multiOption('proto-path');
+    var protos = results.rest;
+
+    if (out == null) {
+      _usage(
+        'The output directory option (--out) is required.',
+        parser,
+        isFailure: true,
+      );
+    } else {
+      final outDir = Directory(out);
+      if (!outDir.existsSync()) {
+        outDir.createSync(recursive: true);
+      }
+    }
+
+    final protoDir = Directory('protos');
+
+    // paths
+
+    for (final dir in protoPaths) {
+      if (!Directory(dir).existsSync()) {
+        _usage(
+          "The --proto-path '$dir' does not exist.",
+          parser,
+          isFailure: true,
+        );
+      }
+    }
+
+    // auto-setup protoPaths
+    if (protoDir.existsSync() && !protoPaths.contains(protoDir.path)) {
+      protoPaths.add(protoDir.path);
+    }
+
+    final defaultProtosPath = calculateDefaultProtosPath();
+    if (defaultProtosPath != null && !protoPaths.contains(defaultProtosPath)) {
+      protoPaths.add(defaultProtosPath);
+    }
+
+    // files
+
+    for (final file in protos) {
+      if (!File(file).existsSync()) {
+        _usage(
+          "The proto file '$file' does not exist.",
+          parser,
+          isFailure: true,
+        );
+      }
+    }
+
+    // We either need an explicit list of files to compile, or that a 'protos'
+    // directory exists.
+    if (protos.isEmpty) {
+      if (protoDir.existsSync()) {
+        final protoFiles = protoDir
+            .listSync(recursive: true)
+            .whereType<File>()
+            .where((file) => file.path.endsWith('.proto'));
+        protos = protoFiles.map((file) => file.path).toList();
+      } else {
+        _usage('No proto files passed.', parser, isFailure: true);
+      }
+    }
+
+    // detect protoc ('protoc --version')
+    if (_protocVersion() == null) {
+      _usage(
+        '''
+'protoc' not found on the path.
+
+See installation options at: https://protobuf.dev/installation/.
+    ''',
+        parser,
+        isFailure: true,
+      );
+    }
+
+    // handle --version
+    if (version) {
+      print(_protocVersion());
+      exit(0);
+    }
+
+    protoc(out: out, grpc: grpc, protoPaths: protoPaths, protos: protos);
+  }
+
+  void protoc({
+    required String out,
+    required bool grpc,
+    required List<String> protoPaths,
+    required List<String> protos,
+  }) async {
+    final execScriptHelper = TempExecScriptHelper();
+    final execScript = execScriptHelper.execScript;
+
+    final args = <String>[];
+    if (grpc) {
+      args.add('--dart_out=grpc:$out');
+    } else {
+      args.add('--dart_out=$out');
+    }
+    args.add('--plugin=${execScript.absolute.path}');
+    args.addAll([...(protoPaths.map((p) => '--proto_path=$p'))]);
+    args.addAll(protos);
+
+    // todo:
+    print('protoc ${args.join(' ')}');
+    print('');
+
+    final process = await Process.start('protoc', args);
+    process.stdout.transform(const Utf8Decoder()).listen((line) {
+      stdout.writeln(line);
+    });
+    process.stderr.transform(const Utf8Decoder()).listen((line) {
+      stderr.writeln(line);
+    });
+    exitCode = await process.exitCode;
+
+    execScriptHelper.dispose();
+  }
+
+  static ArgParser _createArgParser() {
+    final parser = ArgParser();
+
+    parser.addFlag(
+      'help',
+      abbr: 'h',
+      negatable: false,
+      help: 'Print this usage information.',
+    );
+    parser.addFlag(
+      'version',
+      negatable: false,
+      help: 'Display the protoc version in use.',
+    );
+    parser.addMultiOption(
+      'proto-path',
+      valueHelp: 'directory',
+      help: 'Specify the directories in which to search for imported protos.',
+    );
+    parser.addOption(
+      'out',
+      defaultsTo: 'lib/src/gen',
+      valueHelp: 'directory',
+      help: 'The output directory for the generated code.',
+    );
+    parser.addFlag(
+      'grpc',
+      negatable: false,
+      help: 'Generate gRPC service classes.',
+    );
+
+    return parser;
+  }
+
+  Never _usage(String message, ArgParser parser, {bool isFailure = false}) {
+    stderr.writeln(message);
+    stderr.writeln();
+    stderr.writeln(
+      'usage: dart run protoc_plugin:generate [options] <proto files>',
+    );
+    stderr.writeln(parser.usage);
+    exit(isFailure ? 64 : 0);
+  }
+
+  static String? _protocVersion() {
+    final result = Process.runSync('protoc', ['--version']);
+    return result.exitCode == 0 ? (result.stdout as String).trim() : null;
+  }
+}

protoc_plugin/lib/src/generate_utils.dart

@@ -0,0 +1,66 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:io';
+
+import 'package:path/path.dart' as path;
+
+import 'shared.dart';
+
+String? calculateDefaultProtosPath() {
+  var protocPath = which('protoc');
+  if (protocPath == null) {
+    return null;
+  }
+
+  // resolve any symlink
+  if (FileSystemEntity.isLinkSync(protocPath)) {
+    final link = Link(protocPath);
+    protocPath = link.resolveSymbolicLinksSync();
+  }
+
+  // return the include dir
+  // "29.3/bin/protoc-29.3.0" ==> "29.3/include"
+  final rootDir = path.dirname(path.dirname(protocPath));
+  final includeDir = Directory(path.join(rootDir, 'include'));
+  return includeDir.existsSync() ? includeDir.path : null;
+}
+
+/// todo: doc
+class TempExecScriptHelper {
+  late final Directory _tempDir;
+  late final File execScript;
+
+  TempExecScriptHelper() {
+    _tempDir = Directory.systemTemp.createTempSync();
+    execScript = _createTempExecScript(_tempDir);
+  }
+
+  void dispose() {
+    if (_tempDir.existsSync()) {
+      _tempDir.deleteSync(recursive: true);
+    }
+  }
+
+  static File _createTempExecScript(Directory parentDir) {
+    final name = Platform.isWindows ? 'protoc-gen-dart.bat' : 'protoc-gen-dart';
+    final file = File(path.join(parentDir.path, name));
+
+    if (Platform.isWindows) {
+      file.writeAsStringSync(r'''
+@echo off
+dart run protoc_plugin -c "$@"
+''');
+    } else {
+      file.writeAsStringSync(r'''
+#!/bin/bash
+dart run protoc_plugin -c "$@"
+''');
+
+      Process.runSync('chmod', ['+x', file.absolute.path]);
+    }
+
+    return file;
+  }
+}