[pigeon] primitive enums (#4580)

Adds support for enums as parameters and return types. Dart, C++, Java, Kotlin, Objective-C, and swift: Primitive synchronous non-null Primitive synchronous nullable Primitive asynchronous non-null Primitive asynchronous nullable Primitive Flutter api non-null Primitive flutter api nullable Objective-C: Class property nullable Also fixes an issue with nullable enums in classes on objc. This fix required a breaking change that nested all nullable enums in a wrapper class to allow nullability. Also adds the ability to format files before tests run (to make my life better) Also replaces #4756 Also adds objc prefixes to enums fixes: flutter/flutter#87307 fixes: flutter/flutter#118733
flutter · Aug 28, 2023 · 94ba82c · 94ba82c
1 parent bab7bb0
commit 94ba82c
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diff --git a/packages/pigeon/.gitignore b/packages/pigeon/.gitignore
@@ -10,4 +10,4 @@ gradlew.bat
 local.properties
 gradle-wrapper.jar
 bin/pigeon.dart.dill
-
+**/subdirectory/does/not/exist/**
diff --git a/packages/pigeon/CHANGELOG.md b/packages/pigeon/CHANGELOG.md
@@ -1,5 +1,9 @@
-## NEXT
+## 11.0.0
 
+* Adds primitive enum support.
+* Fixes Objective-C nullable enums.
+* **Breaking Change** Changes all nullable enums in Objective-C to be wrapped in custom classes.
+* **Breaking Change** Changes all enums names in Objective-C to have class prefix.
 * Updates minimum supported SDK version to Flutter 3.7/Dart 2.19.
 
 ## 10.1.6
@@ -91,7 +95,7 @@
 ## 9.1.1
 
 * [swift] Removes experimental tags.
-* [kotin] Removes experimental tags.
+* [kotlin] Removes experimental tags.
 
 ## 9.1.0
 

diff --git a/packages/pigeon/README.md b/packages/pigeon/README.md
@@ -23,12 +23,9 @@ Currently pigeon supports generating:
 Pigeon uses the `StandardMessageCodec` so it supports 
 [any datatype platform channels support](https://flutter.dev/docs/development/platform-integration/platform-channels#codec).
 
-Custom classes and nested datatypes are also supported.
+Custom classes, nested datatypes, and enums are also supported. 
 
-#### Enums
-
-Pigeon currently supports enum generation in class fields only.
-See issue: [87307](https://github.com/flutter/flutter/issues/87307).
+Nullable enums in Objective-C generated code will be wrapped in a class to allow for nullability.
 
 ### Synchronous and Asynchronous methods
 

diff --git a/packages/pigeon/example/app/android/app/src/main/java/io/flutter/plugins/Messages.java b/packages/pigeon/example/app/android/app/src/main/java/io/flutter/plugins/Messages.java
@@ -173,7 +173,7 @@ ArrayList<Object> toList() {
       Object description = list.get(1);
       pigeonResult.setDescription((String) description);
       Object code = list.get(2);
-      pigeonResult.setCode(code == null ? null : Code.values()[(int) code]);
+      pigeonResult.setCode(Code.values()[(int) code]);
       Object data = list.get(3);
       pigeonResult.setData((Map<String, String>) data);
       return pigeonResult;

diff --git a/packages/pigeon/example/app/ios/Runner/Messages.g.swift b/packages/pigeon/example/app/ios/Runner/Messages.g.swift
@@ -13,6 +13,10 @@ import FlutterMacOS
 #error("Unsupported platform.")
 #endif
 
+private func isNullish(_ value: Any?) -> Bool {
+  return value is NSNull || value == nil
+}
+
 private func wrapResult(_ result: Any?) -> [Any?] {
   return [result]
 }

diff --git a/packages/pigeon/example/app/macos/Runner/messages.g.h b/packages/pigeon/example/app/macos/Runner/messages.g.h
@@ -18,6 +18,12 @@ typedef NS_ENUM(NSUInteger, PGNCode) {
   PGNCodeTwo = 1,
 };
 
+/// Wrapper for PGNCode to allow for nullability.
+@interface PGNCodeBox : NSObject
+@property(nonatomic, assign) PGNCode value;
+- (instancetype)initWithValue:(PGNCode)value;
+@end
+
 @class PGNMessageData;
 
 @interface PGNMessageData : NSObject

diff --git a/packages/pigeon/example/app/macos/Runner/messages.g.m b/packages/pigeon/example/app/macos/Runner/messages.g.m
@@ -16,6 +16,16 @@
 #error File requires ARC to be enabled.
 #endif
 
+@implementation PGNCodeBox
+- (instancetype)initWithValue:(PGNCode)value {
+  self = [super init];
+  if (self) {
+    _value = value;
+  }
+  return self;
+}
+@end
+
 static NSArray *wrapResult(id result, FlutterError *error) {
   if (error) {
     return @[

diff --git a/packages/pigeon/lib/cpp_generator.dart b/packages/pigeon/lib/cpp_generator.dart
@@ -888,9 +888,14 @@ class CppSourceGenerator extends StructuredGenerator<CppOptions> {
             indent.writeln(
                 'std::unique_ptr<EncodableValue> response = GetCodec().DecodeMessage(reply, reply_size);');
             indent.writeln('const auto& $encodedReplyName = *response;');
-            _writeEncodableValueArgumentUnwrapping(indent, returnType,
-                argName: successCallbackArgument,
-                encodableArgName: encodedReplyName);
+            _writeEncodableValueArgumentUnwrapping(
+              indent,
+              root,
+              returnType,
+              argName: successCallbackArgument,
+              encodableArgName: encodedReplyName,
+              apiType: ApiType.flutter,
+            );
           }
           indent.writeln('on_success($successCallbackArgument);');
         });
@@ -968,9 +973,19 @@ class CppSourceGenerator extends StructuredGenerator<CppOptions> {
                         indent.writeln('return;');
                       });
                     }
-                    _writeEncodableValueArgumentUnwrapping(indent, hostType,
-                        argName: argName, encodableArgName: encodableArgName);
-                    methodArgument.add(argName);
+                    _writeEncodableValueArgumentUnwrapping(
+                      indent,
+                      root,
+                      hostType,
+                      argName: argName,
+                      encodableArgName: encodableArgName,
+                      apiType: ApiType.host,
+                    );
+                    final String unwrapEnum =
+                        isEnum(root, arg.type) && arg.type.isNullable
+                            ? ' ? &(*$argName) : nullptr'
+                            : '';
+                    methodArgument.add('$argName$unwrapEnum');
                   });
                 }
 
@@ -1198,29 +1213,35 @@ return EncodableValue(EncodableList{
     final String errorGetter;
 
     const String nullValue = 'EncodableValue()';
+    String enumPrefix = '';
+    if (isEnum(root, returnType)) {
+      enumPrefix = '(int) ';
+    }
     if (returnType.isVoid) {
       nonErrorPath = '${prefix}wrapped.push_back($nullValue);';
       errorCondition = 'output.has_value()';
       errorGetter = 'value';
     } else {
       final HostDatatype hostType = getHostDatatype(returnType, root.classes,
           root.enums, _shortBaseCppTypeForBuiltinDartType);
+
       const String extractedValue = 'std::move(output).TakeValue()';
-      final String wrapperType =
-          hostType.isBuiltin ? 'EncodableValue' : 'CustomEncodableValue';
+      final String wrapperType = hostType.isBuiltin || isEnum(root, returnType)
+          ? 'EncodableValue'
+          : 'CustomEncodableValue';
       if (returnType.isNullable) {
         // The value is a std::optional, so needs an extra layer of
         // handling.
         nonErrorPath = '''
 ${prefix}auto output_optional = $extractedValue;
 ${prefix}if (output_optional) {
-$prefix\twrapped.push_back($wrapperType(std::move(output_optional).value()));
+$prefix\twrapped.push_back($wrapperType(${enumPrefix}std::move(output_optional).value()));
 $prefix} else {
 $prefix\twrapped.push_back($nullValue);
 $prefix}''';
       } else {
         nonErrorPath =
-            '${prefix}wrapped.push_back($wrapperType($extractedValue));';
+            '${prefix}wrapped.push_back($wrapperType($enumPrefix$extractedValue));';
       }
       errorCondition = 'output.has_error()';
       errorGetter = 'error';
@@ -1297,9 +1318,11 @@ ${prefix}reply(EncodableValue(std::move(wrapped)));''';
   /// existing EncodableValue variable called [encodableArgName].
   void _writeEncodableValueArgumentUnwrapping(
     Indent indent,
+    Root root,
     HostDatatype hostType, {
     required String argName,
     required String encodableArgName,
+    required ApiType apiType,
   }) {
     if (hostType.isNullable) {
       // Nullable arguments are always pointers, with nullptr corresponding to
@@ -1320,6 +1343,22 @@ ${prefix}reply(EncodableValue(std::move(wrapped)));''';
       } else if (hostType.isBuiltin) {
         indent.writeln(
             'const auto* $argName = std::get_if<${hostType.datatype}>(&$encodableArgName);');
+      } else if (hostType.isEnum) {
+        if (hostType.isNullable) {
+          final String valueVarName = '${argName}_value';
+          indent.writeln(
+              'const int64_t $valueVarName = $encodableArgName.IsNull() ? 0 : $encodableArgName.LongValue();');
+          if (apiType == ApiType.flutter) {
+            indent.writeln(
+                'const auto* $argName = $encodableArgName.IsNull() ? nullptr : &(${hostType.datatype})$valueVarName;');
+          } else {
+            indent.writeln(
+                'const auto $argName = $encodableArgName.IsNull() ? std::nullopt : std::make_optional<${hostType.datatype}>(static_cast<${hostType.datatype}>(${argName}_value));');
+          }
+        } else {
+          indent.writeln(
+              'const auto* $argName = &((${hostType.datatype})std::get<int>($encodableArgName));');
+        }
       } else {
         indent.writeln(
             'const auto* $argName = &(std::any_cast<const ${hostType.datatype}&>(std::get<CustomEncodableValue>($encodableArgName)));');
@@ -1342,6 +1381,9 @@ ${prefix}reply(EncodableValue(std::move(wrapped)));''';
       } else if (hostType.isBuiltin) {
         indent.writeln(
             'const auto& $argName = std::get<${hostType.datatype}>($encodableArgName);');
+      } else if (hostType.isEnum) {
+        indent.writeln(
+            'const ${hostType.datatype}& $argName = (${hostType.datatype})$encodableArgName.LongValue();');
       } else {
         indent.writeln(
             'const auto& $argName = std::any_cast<const ${hostType.datatype}&>(std::get<CustomEncodableValue>($encodableArgName));');
@@ -1390,7 +1432,11 @@ String _getSafeArgumentName(int count, NamedType argument) =>
 /// Returns a non-nullable variant of [type].
 HostDatatype _nonNullableType(HostDatatype type) {
   return HostDatatype(
-      datatype: type.datatype, isBuiltin: type.isBuiltin, isNullable: false);
+    datatype: type.datatype,
+    isBuiltin: type.isBuiltin,
+    isNullable: false,
+    isEnum: type.isEnum,
+  );
 }
 
 String _pascalCaseFromCamelCase(String camelCase) =>

diff --git a/packages/pigeon/lib/dart_generator.dart b/packages/pigeon/lib/dart_generator.dart
@@ -411,7 +411,7 @@ $resultAt != null
                     final String leftHandSide = 'final $argType? $argName';
                     if (customEnumNames.contains(arg.type.baseName)) {
                       indent.writeln(
-                          '$leftHandSide = $argsArray[$count] == null ? null : $argType.values[$argsArray[$count] as int];');
+                          '$leftHandSide = $argsArray[$count] == null ? null : $argType.values[$argsArray[$count]! as int];');
                     } else {
                       indent.writeln(
                           '$leftHandSide = ($argsArray[$count] as $genericArgType?)${castCall.isEmpty ? '' : '?$castCall'};');
@@ -442,10 +442,15 @@ $resultAt != null
                   } else {
                     indent.writeln('final $returnType output = $call;');
                   }
+
                   const String returnExpression = 'output';
+                  final String nullability =
+                      func.returnType.isNullable ? '?' : '';
+                  final String valueExtraction =
+                      isEnum(root, func.returnType) ? '$nullability.index' : '';
                   final String returnStatement = isMockHandler
-                      ? 'return <Object?>[$returnExpression];'
-                      : 'return $returnExpression;';
+                      ? 'return <Object?>[$returnExpression$valueExtraction];'
+                      : 'return $returnExpression$valueExtraction;';
                   indent.writeln(returnStatement);
                 }
               });
@@ -487,6 +492,8 @@ $resultAt != null
       codecName = _getCodecName(api);
       _writeCodec(indent, codecName, api, root);
     }
+    final List<String> customEnumNames =
+        root.enums.map((Enum x) => x.name).toList();
     indent.newln();
     bool first = true;
     addDocumentationComments(
@@ -553,9 +560,21 @@ final BinaryMessenger? _binaryMessenger;
           final String nullHandler = func.returnType.isNullable
               ? (genericCastCall.isEmpty ? '' : '?')
               : '!';
-          final String returnStatement = func.returnType.isVoid
-              ? 'return;'
-              : 'return $nullablyTypedAccessor$nullHandler$genericCastCall;';
+          String returnStatement = 'return';
+          if (customEnumNames.contains(returnType)) {
+            if (func.returnType.isNullable) {
+              returnStatement =
+                  '$returnStatement ($accessor as int?) == null ? null : $returnType.values[$accessor! as int]';
+            } else {
+              returnStatement =
+                  '$returnStatement $returnType.values[$accessor! as int]';
+            }
+          } else if (!func.returnType.isVoid) {
+            returnStatement =
+                '$returnStatement $nullablyTypedAccessor$nullHandler$genericCastCall';
+          }
+          returnStatement = '$returnStatement;';
+
           indent.format('''
 final List<Object?>? replyList =
 \t\tawait channel.send($sendArgument) as List<Object?>?;

diff --git a/packages/pigeon/lib/generator_tools.dart b/packages/pigeon/lib/generator_tools.dart
@@ -13,7 +13,7 @@ import 'ast.dart';
 /// The current version of pigeon.
 ///
 /// This must match the version in pubspec.yaml.
-const String pigeonVersion = '10.1.6';
+const String pigeonVersion = '11.0.0';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {
@@ -176,6 +176,7 @@ class HostDatatype {
     required this.datatype,
     required this.isBuiltin,
     required this.isNullable,
+    required this.isEnum,
   });
 
   /// The [String] that can be printed into host code to represent the type.
@@ -186,6 +187,9 @@ class HostDatatype {
 
   /// `true` if the type corresponds to a nullable Dart datatype.
   final bool isNullable;
+
+  /// `true if the type is a custom enum.
+  final bool isEnum;
 }
 
 /// Calculates the [HostDatatype] for the provided [NamedType].
@@ -226,20 +230,32 @@ HostDatatype _getHostDatatype(TypeDeclaration type, List<Class> classes,
           ? customResolver(type.baseName)
           : type.baseName;
       return HostDatatype(
-          datatype: customName, isBuiltin: false, isNullable: type.isNullable);
+        datatype: customName,
+        isBuiltin: false,
+        isNullable: type.isNullable,
+        isEnum: false,
+      );
     } else if (enums.map((Enum x) => x.name).contains(type.baseName)) {
       final String customName = customResolver != null
           ? customResolver(type.baseName)
           : type.baseName;
       return HostDatatype(
-          datatype: customName, isBuiltin: false, isNullable: type.isNullable);
+        datatype: customName,
+        isBuiltin: false,
+        isNullable: type.isNullable,
+        isEnum: true,
+      );
     } else {
       throw Exception(
           'unrecognized datatype ${fieldName == null ? '' : 'for field:"$fieldName" '}of type:"${type.baseName}"');
     }
   } else {
     return HostDatatype(
-        datatype: datatype, isBuiltin: true, isNullable: type.isNullable);
+      datatype: datatype,
+      isBuiltin: true,
+      isNullable: type.isNullable,
+      isEnum: false,
+    );
   }
 }
 
@@ -574,6 +590,15 @@ String? deducePackageName(String mainDartFile) {
   }
 }
 
+/// Enum to specify api type when generating code.
+enum ApiType {
+  /// Flutter api.
+  flutter,
+
+  /// Host api.
+  host,
+}
+
 /// Enum to specify which file will be generated for multi-file generators
 enum FileType {
   /// header file.