fix(mason): use file descriptor pooling

.github/workflows/mason.yaml

@@ -6,13 +6,15 @@ on:
       - master
     paths:
       - .github/workflows/mason.yaml
+      - packages/mason_logger/**
       - packages/mason/**
 
   pull_request:
     branches:
       - master
     paths:
       - .github/workflows/mason.yaml
+      - packages/mason_logger/**
       - packages/mason/**
 
 jobs:

.github/workflows/mason_cli.yaml

@@ -6,13 +6,19 @@ on:
       - master
     paths:
       - .github/workflows/mason_cli.yaml
+      - packages/mason_logger/**
+      - packages/mason_api/**
+      - packages/mason/**
       - packages/mason_cli/**
 
   pull_request:
     branches:
       - master
     paths:
       - .github/workflows/mason_cli.yaml
+      - packages/mason_logger/**
+      - packages/mason_api/**
+      - packages/mason/**
       - packages/mason_cli/**
 
 jobs:

packages/mason/lib/src/generator.dart

@@ -11,9 +11,11 @@ import 'package:mason/mason.dart';
 import 'package:mason/src/compute.dart';
 import 'package:meta/meta.dart';
 import 'package:path/path.dart' as p;
+import 'package:pool/pool.dart';
 
 part 'hooks.dart';
 
+final _descriptorPool = Pool(32);
 final _partialRegExp = RegExp(r'\{\{~\s(.+)\s\}\}');
 final _fileRegExp = RegExp(r'{{%\s?([a-zA-Z]+)\s?%}}');
 final _delimeterRegExp = RegExp('{{([^;,=]*?)}}');
@@ -88,6 +90,7 @@ class MasonGenerator extends Generator {
         .whereType<File>()
         .map((file) {
       return () async {
+        final resource = await _descriptorPool.request();
         try {
           final content = await File(file.path).readAsBytes();
           final relativePath = file.path.substring(
@@ -96,6 +99,8 @@ class MasonGenerator extends Generator {
           return TemplateFile.fromBytes(relativePath, content);
         } on Exception {
           return null;
+        } finally {
+          resource.release();
         }
       }();
     });

packages/mason/pubspec.yaml

@@ -21,6 +21,7 @@ dependencies:
   meta: ^1.7.0
   mustache_template: ^2.0.0
   path: ^1.8.0
+  pool: ^1.5.1
   pub_semver: ^2.1.0
   recase: ^4.0.0
   yaml: ^3.1.0

packages/mason/test/src/generator_test.dart

@@ -134,6 +134,29 @@ void main() {
         expect(production.readAsStringSync(), equals('PRODUCTION'));
       });
 
+      test('constructs an instance (loops stress test)', () async {
+        const fileCount = 1000;
+        final brick = Brick.path(
+          path.join('test', 'bricks', 'loop'),
+        );
+        final generator = await MasonGenerator.fromBrick(brick);
+        final tempDir = Directory.systemTemp.createTempSync();
+        final files = await generator.generate(
+          DirectoryGeneratorTarget(tempDir),
+          vars: <String, dynamic>{
+            'values': List.generate(fileCount, (index) => '$index'),
+          },
+        );
+
+        expect(files.length, equals(fileCount));
+        expect(
+          files.every(
+            (element) => element.status == GeneratedFileStatus.created,
+          ),
+          isTrue,
+        );
+      });
+
       test('constructs an instance with hooks', () async {
         const name = 'Dash';
         final brick = Brick.path(