Factor out flutter manifest logic (#12237)

packages/flutter_tools/lib/src/flutter_manifest.dart

+// Copyright 2017 The Chromium Authors. 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:async';
+
+import 'package:flutter_tools/src/globals.dart';
+import 'package:json_schema/json_schema.dart';
+import 'package:yaml/yaml.dart';
+
+import 'base/file_system.dart';
+import 'cache.dart';
+
+/// A wrapper around the `flutter` section in the  `pubspec.yaml` file.
+class FlutterManifest {
+  FlutterManifest._();
+
+  /// Returns null on missing or invalid manifest
+  static Future<FlutterManifest> createFromPath(String path) async {
+    return  _createFromYaml(await _loadFlutterManifest(path));
+  }
+  /// Returns null on missing or invalid manifest
+  static Future<FlutterManifest> createFromString(String manifest) async {
+    return _createFromYaml(loadYaml(manifest));
+  }
+
+  static Future<FlutterManifest> _createFromYaml(Object yamlDocument) async {
+    final FlutterManifest pubspec = new FlutterManifest._();
+    if (yamlDocument == null || !await _validate(yamlDocument))
+      return null;
+
+    pubspec._descriptor = yamlDocument;
+    pubspec._flutterDescriptor = pubspec._descriptor['flutter'] ?? <String, dynamic>{};
+    return pubspec;
+  }
+
+  /// A map representation of the entire `pubspec.yaml` file.
+  Map<String, dynamic> _descriptor;
+
+  /// A map representation of the `flutter` section in the `pubspec.yaml` file.
+  Map<String, dynamic> _flutterDescriptor;
+
+  String get appName => _descriptor['name'];
+
+  bool get usesMaterialDesign {
+    return _flutterDescriptor['uses-material-design'] ?? false;
+  }
+
+  List<Map<String, dynamic>> get fontsDescriptor {
+   return _flutterDescriptor['fonts'] ?? const <Map<String, dynamic>>[];
+  }
+
+  List<String> get assets {
+    return _flutterDescriptor['assets'] ?? const <String>[];
+  }
+
+  List<Font> _fonts;
+
+  List<Font> get fonts {
+    _fonts ??= _extractFonts();
+    return _fonts;
+  }
+
+  List<Font> _extractFonts() {
+    if (!_flutterDescriptor.containsKey('fonts'))
+      return <Font>[];
+
+    final List<Font> fonts = <Font>[];
+    for (Map<String, dynamic> fontFamily in _flutterDescriptor['fonts']) {
+      final List<Map<String, dynamic>> fontFiles = fontFamily['fonts'];
+      final String familyName = fontFamily['family'];
+      if (familyName == null) {
+        printError('Warning: Missing family name for font.', emphasis: true);
+        continue;
+      }
+      if (fontFiles == null) {
+        printError('Warning: No fonts specified for font $familyName', emphasis: true);
+        continue;
+      }
+
+      final List<FontAsset> fontAssets = <FontAsset>[];
+      for (Map<String, dynamic> fontFile in fontFiles) {
+        final String asset = fontFile['asset'];
+        if (asset == null) {
+          printError('Warning: Missing asset in fonts for $familyName', emphasis: true);
+          continue;
+        }
+
+        fontAssets.add(new FontAsset(
+          asset,
+          weight: fontFile['weight'],
+          style: fontFile['style'],
+        ));
+      }
+      if (fontAssets.isNotEmpty)
+        fonts.add(new Font(fontFamily['family'], fontAssets));
+    }
+    return fonts;
+  }
+}
+
+class Font {
+  Font(this.familyName, this.fontAssets) {
+    assert(familyName != null);
+    assert(fontAssets != null);
+    assert(fontAssets.isNotEmpty);
+  }
+
+  final String familyName;
+  final List<FontAsset> fontAssets;
+
+  Map<String, dynamic> get descriptor {
+    return <String, dynamic>{
+      'family': familyName,
+      'fonts': fontAssets.map((FontAsset a) => a.descriptor).toList(),
+    };
+  }
+
+  @override
+  String toString() => '$runtimeType(family: $familyName, assets: $fontAssets)';
+}
+
+class FontAsset {
+  FontAsset(this.asset, {this.weight, this.style}) {
+    assert(asset != null);
+  }
+
+  final String asset;
+  final int weight;
+  final String style;
+
+  Map<String, dynamic> get descriptor {
+    final Map<String, dynamic> descriptor = <String, dynamic>{};
+    if (weight != null)
+      descriptor['weight'] = weight;
+
+    if (style != null)
+      descriptor['style'] = style;
+
+    descriptor['asset'] = asset;
+    return descriptor;
+  }
+
+  @override
+  String toString() => '$runtimeType(asset: $asset, weight; $weight, style: $style)';
+}
+
+Future<dynamic> _loadFlutterManifest(String manifestPath) async {
+  if (manifestPath == null || !fs.isFileSync(manifestPath))
+    return null;
+  final String manifestDescriptor = await fs.file(manifestPath).readAsString();
+  return loadYaml(manifestDescriptor);
+}
+
+Future<bool> _validate(Object manifest) async {
+  final String schemaPath = fs.path.join(
+    fs.path.absolute(Cache.flutterRoot), 'packages', 'flutter_tools', 'schema',
+    'pubspec_yaml.json',
+  );
+  final Schema schema = await Schema.createSchemaFromUrl(fs.path.toUri(schemaPath).toString());
+
+  final Validator validator = new Validator(schema);
+  if (validator.validate(manifest)) {
+    return true;
+  } else {
+    printStatus('Error detected in pubspec.yaml:', emphasis: true);
+    printError(validator.errors.join('\n'));
+    return false;
+  }
+}
\ No newline at end of file

packages/flutter_tools/test/asset_bundle_package_fonts_test.dart

@@ -180,8 +180,8 @@ $fontsSection
       writeFontAsset('p/p/', font);
 
       final String expectedFontManifest =
-          '[{"fonts":[{"asset":"packages/test_package/a/bar"}],'
-          '"family":"packages/test_package/foo"}]';
+          '[{"family":"packages/test_package/foo",'
+          '"fonts":[{"asset":"packages/test_package/a/bar"}]}]';
       await buildAndVerifyFonts(
         <String>[],
         <String>[font],
@@ -211,8 +211,8 @@ $fontsSection
       writeFontAsset('p2/p/lib/', font);
 
       final String expectedFontManifest =
-          '[{"fonts":[{"asset":"packages/test_package2/bar"}],'
-          '"family":"packages/test_package/foo"}]';
+          '[{"family":"packages/test_package/foo",'
+          '"fonts":[{"asset":"packages/test_package2/bar"}]}]';
       await buildAndVerifyFonts(
         <String>[],
         <String>[font],
@@ -243,8 +243,8 @@ $fontsSection
       writeFontAsset('p/p/', font);
 
       final String expectedFontManifest =
-          '[{"fonts":[{"weight":400,"style":"italic","asset":"packages/test_package/a/bar"}],'
-          '"family":"packages/test_package/foo"}]';
+          '[{"family":"packages/test_package/foo",'
+          '"fonts":[{"weight":400,"style":"italic","asset":"packages/test_package/a/bar"}]}]';
       await buildAndVerifyFonts(
         <String>[],
         <String>[font],
@@ -278,9 +278,9 @@ $fontsSection
       writeFontAsset('p/p/', font);
 
       final String expectedFontManifest =
-          '[{"fonts":[{"asset":"packages/test_package/a/bar"}],'
-          '"family":"packages/test_package/foo"},'
-          '{"fonts":[{"asset":"a/bar"}],"family":"foo"}]';
+          '[{"fonts":[{"asset":"a/bar"}],"family":"foo"},'
+          '{"family":"packages/test_package/foo",'
+          '"fonts":[{"asset":"packages/test_package/a/bar"}]}]';
       await buildAndVerifyFonts(
         <String>[font],
         <String>[font],