[pigeon] Add support for multiple part files

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 27.2.0
+
+* Adds support for parsing Pigeon definitions split across multiple Dart `part`
+  files.
+
 ## 27.1.0
 
 * [swift] Adds `CaseIterable` conformance to generated enums.

packages/pigeon/lib/src/generator_tools.dart

@@ -15,7 +15,7 @@ import 'generator.dart';
 /// The current version of pigeon.
 ///
 /// This must match the version in pubspec.yaml.
-const String pigeonVersion = '27.1.0';
+const String pigeonVersion = '27.2.0';
 
 /// Default plugin package name.
 const String defaultPluginPackageName = 'dev.flutter.pigeon';

packages/pigeon/lib/src/pigeon_lib.dart

@@ -12,6 +12,7 @@ import 'package:analyzer/dart/analysis/analysis_context_collection.dart'
     show AnalysisContextCollection;
 import 'package:analyzer/dart/analysis/results.dart' show ParsedUnitResult;
 import 'package:analyzer/dart/analysis/session.dart' show AnalysisSession;
+import 'package:analyzer/dart/analysis/utilities.dart' show parseString;
 import 'package:analyzer/dart/ast/ast.dart' as dart_ast;
 import 'package:analyzer/diagnostic/diagnostic.dart' show Diagnostic;
 import 'package:args/args.dart';
@@ -450,25 +451,54 @@ class Pigeon {
   /// [sdkPath] for specifying the Dart SDK path for
   /// [AnalysisContextCollection].
   ParseResults parseFile(String inputPath, {String? sdkPath}) {
-    final includedPaths = <String>[path.absolute(path.normalize(inputPath))];
-    final collection = AnalysisContextCollection(includedPaths: includedPaths, sdkPath: sdkPath);
+    final String normalizedInputPath = path.absolute(path.normalize(inputPath));
+    final _CollectedInput input = _collectInputAndParts(normalizedInputPath);
+    if (input.missingPath != null) {
+      return ParseResults(
+        root: Root.makeEmpty(),
+        errors: <Error>[
+          Error(
+            message: 'File ${input.missingPath} does not exist',
+            filename: input.missingPath,
+          ),
+        ],
+        pigeonOptions: null,
+      );
+    }
+
+    final collection = AnalysisContextCollection(
+      includedPaths: input.paths,
+      sdkPath: sdkPath,
+    );
 
     final compilationErrors = <Error>[];
-    final rootBuilder = RootBuilder(File(inputPath).readAsStringSync());
+    final String rootInputString = _getInputString(
+      inputPath: normalizedInputPath,
+      contents: input.contents,
+      units: input.units,
+      paths: input.paths,
+    );
+    final rootBuilder = RootBuilder(rootInputString);
+    final dart_ast.CompilationUnit mergedUnit = parseString(
+      content: rootInputString,
+      path: normalizedInputPath,
+      throwIfDiagnostics: false,
+    ).unit;
+    mergedUnit.accept(rootBuilder);
     for (final AnalysisContext context in collection.contexts) {
-      for (final String path in context.contextRoot.analyzedFiles()) {
+      for (final String path in input.paths) {
         final AnalysisSession session = context.currentSession;
         final result = session.getParsedUnit(path) as ParsedUnitResult;
-        if (result.diagnostics.isEmpty) {
-          final dart_ast.CompilationUnit unit = result.unit;
-          unit.accept(rootBuilder);
-        } else {
+        if (result.diagnostics.isNotEmpty) {
           for (final Diagnostic diagnostic in result.diagnostics) {
             compilationErrors.add(
               Error(
                 message: diagnostic.message,
                 filename: diagnostic.source.fullName,
-                lineNumber: calculateLineNumber(diagnostic.source.contents.data, diagnostic.offset),
+                lineNumber: calculateLineNumber(
+                  diagnostic.source.contents.data,
+                  diagnostic.offset,
+                ),
               ),
             );
           }
@@ -483,6 +513,151 @@ class Pigeon {
     }
   }
 
+  String? _readFileOrNull(String filePath) {
+    final file = File(filePath);
+    if (!file.existsSync()) {
+      return null;
+    }
+    return file.readAsStringSync();
+  }
+
+  List<String> _getPartPaths(
+    Iterable<dart_ast.Directive> directives, {
+    required String sourcePath,
+  }) {
+    final parts = <String>[];
+    for (final directive in directives) {
+      if (directive is dart_ast.PartDirective) {
+        final String? uri = directive.uri.stringValue;
+        if (uri != null) {
+          parts.add(
+            path.absolute(
+              path.normalize(path.join(path.dirname(sourcePath), uri)),
+            ),
+          );
+        }
+      }
+    }
+    return parts;
+  }
+
+  ({String body, List<String> imports}) _stripPartsAndCollectImports({
+    required String sourceContent,
+    required dart_ast.CompilationUnit unit,
+    required bool collectImports,
+  }) {
+    final imports = <String>[];
+    final removalRanges = <({int start, int end})>[];
+    for (final dart_ast.Directive directive in unit.directives) {
+      if (directive is dart_ast.ImportDirective) {
+        if (collectImports) {
+          imports.add(
+            sourceContent
+                .substring(directive.offset, directive.end)
+                .trimRight(),
+          );
+        }
+        removalRanges.add((start: directive.offset, end: directive.end));
+      } else if (directive is dart_ast.PartDirective ||
+          directive is dart_ast.PartOfDirective ||
+          directive is dart_ast.LibraryDirective) {
+        removalRanges.add((start: directive.offset, end: directive.end));
+      }
+    }
+
+    final body = StringBuffer();
+    var start = 0;
+    for (final range in removalRanges) {
+      body.write(sourceContent.substring(start, range.start));
+      start = range.end;
+    }
+    body.write(sourceContent.substring(start));
+    return (body: body.toString().trim(), imports: imports);
+  }
+
+  String _getInputString({
+    required String inputPath,
+    required List<String> paths,
+    required Map<String, String> contents,
+    required Map<String, dart_ast.CompilationUnit> units,
+  }) {
+    final ({String body, List<String> imports}) mainResult =
+        _stripPartsAndCollectImports(
+          sourceContent: contents[inputPath]!,
+          unit: units[inputPath]!,
+          collectImports: true,
+        );
+    final List<String> imports = mainResult.imports;
+    final partBodies = <String>[];
+    for (final String currentPath in paths.skip(1)) {
+      final ({String body, List<String> imports}) partResult =
+          _stripPartsAndCollectImports(
+            sourceContent: contents[currentPath]!,
+            unit: units[currentPath]!,
+            collectImports: false,
+          );
+      partBodies.add(partResult.body);
+    }
+
+    final output = StringBuffer();
+    if (imports.isNotEmpty) {
+      output.writeln(imports.join('\n'));
+      output.writeln();
+    }
+    output.writeln(mainResult.body);
+    for (final partBody in partBodies) {
+      if (partBody.isNotEmpty) {
+        output.writeln();
+        output.writeln();
+        output.write(partBody);
+      }
+    }
+    return output.toString().trimRight();
+  }
+
+  _CollectedInput _collectInputAndParts(String inputPath) {
+    final paths = <String>[];
+    final contents = <String, String>{};
+    final units = <String, dart_ast.CompilationUnit>{};
+    final pending = <String>[inputPath];
+    final seen = <String>{};
+    while (pending.isNotEmpty) {
+      final String currentPath = pending.removeAt(0);
+      if (seen.contains(currentPath)) {
+        continue;
+      }
+      seen.add(currentPath);
+      final String? content = _readFileOrNull(currentPath);
+      if (content == null) {
+        return _CollectedInput(
+          paths: paths,
+          contents: contents,
+          units: units,
+          missingPath: currentPath,
+        );
+      }
+      final dart_ast.CompilationUnit unit = parseString(
+        content: content,
+        path: currentPath,
+        throwIfDiagnostics: false,
+      ).unit;
+      paths.add(currentPath);
+      contents[currentPath] = content;
+      units[currentPath] = unit;
+      final List<String> partPaths = _getPartPaths(
+        unit.directives,
+        sourcePath: currentPath,
+      );
+      pending.addAll(partPaths);
+    }
+    return _CollectedInput(
+      paths: paths,
+      contents: contents,
+      units: units,
+      missingPath: null,
+    );
+  }
+
   /// String that describes how the tool is used.
   static String get usage {
     return '''
@@ -796,3 +971,17 @@ class ParseResults {
   /// [ConfigurePigeon] during parsing.
   final Map<String, Object>? pigeonOptions;
 }
+
+class _CollectedInput {
+  _CollectedInput({
+    required this.paths,
+    required this.contents,
+    required this.units,
+    required this.missingPath,
+  });
+
+  final List<String> paths;
+  final Map<String, String> contents;
+  final Map<String, dart_ast.CompilationUnit> units;
+  final String? missingPath;
+}

packages/pigeon/pigeons/core_tests.dart

@@ -4,6 +4,8 @@
 
 import 'package:pigeon/pigeon.dart';
 
+part 'core_tests_small_apis.dart';
+
 enum AnEnum { one, two, three, fortyTwo, fourHundredTwentyTwo }
 
 // Enums require special logic, having multiple ensures that the logic can be
@@ -1413,55 +1415,3 @@ abstract class FlutterIntegrationCoreApi {
   @SwiftFunction('echoAsync(_:)')
   String echoAsyncString(String aString);
 }
-
-/// An API that can be implemented for minimal, compile-only tests.
-//
-// This is also here to test that multiple host APIs can be generated
-// successfully in all languages (e.g., in Java where it requires having a
-// wrapper class).
-@HostApi()
-abstract class HostTrivialApi {
-  void noop();
-}
-
-/// A simple API implemented in some unit tests.
-//
-// This is separate from HostIntegrationCoreApi to avoid having to update a
-// lot of unit tests every time we add something to the integration test API.
-// TODO(stuartmorgan): Restructure the unit tests to reduce the number of
-// different APIs we define.
-@HostApi()
-abstract class HostSmallApi {
-  @async
-  @ObjCSelector('echoString:')
-  String echo(String aString);
-
-  @async
-  void voidVoid();
-}
-
-/// A simple API called in some unit tests.
-//
-// This is separate from FlutterIntegrationCoreApi to allow for incrementally
-// moving from the previous fragmented unit test structure to something more
-// unified.
-// TODO(stuartmorgan): Restructure the unit tests to reduce the number of
-// different APIs we define.
-@FlutterApi()
-abstract class FlutterSmallApi {
-  @ObjCSelector('echoWrappedList:')
-  @SwiftFunction('echo(_:)')
-  TestMessage echoWrappedList(TestMessage msg);
-
-  @ObjCSelector('echoString:')
-  @SwiftFunction('echo(string:)')
-  String echoString(String aString);
-}
-
-/// A data class containing a List, used in unit tests.
-// TODO(stuartmorgan): Evaluate whether these unit tests are still useful; see
-// TODOs above about restructuring.
-class TestMessage {
-  // ignore: always_specify_types, strict_raw_type
-  List? testList;
-}

packages/pigeon/pigeons/core_tests_small_apis.dart

@@ -0,0 +1,57 @@
+// Copyright 2013 The Flutter Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+part of 'core_tests.dart';
+
+/// An API that can be implemented for minimal, compile-only tests.
+//
+// This is also here to test that multiple host APIs can be generated
+// successfully in all languages (e.g., in Java where it requires having a
+// wrapper class).
+@HostApi()
+abstract class HostTrivialApi {
+  void noop();
+}
+
+/// A simple API implemented in some unit tests.
+//
+// This is separate from HostIntegrationCoreApi to avoid having to update a
+// lot of unit tests every time we add something to the integration test API.
+// TODO(stuartmorgan): Restructure the unit tests to reduce the number of
+// different APIs we define.
+@HostApi()
+abstract class HostSmallApi {
+  @async
+  @ObjCSelector('echoString:')
+  String echo(String aString);
+
+  @async
+  void voidVoid();
+}
+
+/// A simple API called in some unit tests.
+//
+// This is separate from FlutterIntegrationCoreApi to allow for incrementally
+// moving from the previous fragmented unit test structure to something more
+// unified.
+// TODO(stuartmorgan): Restructure the unit tests to reduce the number of
+// different APIs we define.
+@FlutterApi()
+abstract class FlutterSmallApi {
+  @ObjCSelector('echoWrappedList:')
+  @SwiftFunction('echo(_:)')
+  TestMessage echoWrappedList(TestMessage msg);
+
+  @ObjCSelector('echoString:')
+  @SwiftFunction('echo(string:)')
+  String echoString(String aString);
+}
+
+/// A data class containing a List, used in unit tests.
+// TODO(stuartmorgan): Evaluate whether these unit tests are still useful; see
+// TODOs above about restructuring.
+class TestMessage {
+  // ignore: always_specify_types, strict_raw_type
+  List? testList;
+}

packages/pigeon/pubspec.yaml

@@ -2,7 +2,7 @@ name: pigeon
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 repository: https://github.com/flutter/packages/tree/main/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+pigeon%22
-version: 27.1.0 # This must match the version in lib/src/generator_tools.dart
+version: 27.2.0 # This must match the version in lib/src/generator_tools.dart
 
 environment:
   sdk: ^3.10.0