[swift2objc] Filtering Support (#1730)

pkgs/swift2objc/lib/src/config.dart

@@ -1,5 +1,7 @@
 import 'package:path/path.dart' as path;
 
+import 'ast/_core/interfaces/declaration.dart';
+
 const defaultTempDirPrefix = 'swift2objc_temp_';
 const symbolgraphFileSuffix = '.symbols.json';
 
@@ -32,12 +34,21 @@ class Config {
   /// intermediate files after generating the wrapper.
   final Uri? tempDir;
 
-  const Config({
-    required this.input,
-    required this.outputFile,
-    this.tempDir,
-    this.preamble,
-  });
+  /// Filter function to filter APIs
+  ///
+  /// APIs can be filtered by name
+  ///
+  /// Includes all declarations by default
+  final bool Function(Declaration declaration) include;
+
+  static bool _defaultInclude(_) => true;
+
+  const Config(
+      {required this.input,
+      required this.outputFile,
+      this.tempDir,
+      this.preamble,
+      this.include = Config._defaultInclude});
 }
 
 /// Used to specify the inputs in the `config` object.

pkgs/swift2objc/lib/src/generate_wrapper.dart

@@ -46,8 +46,8 @@ Future<void> generateWrapper(Config config) async {
   };
 
   final declarations = parseAst(symbolgraphJson);
-  final transformedDeclarations = transform(declarations);
-
+  final transformedDeclarations =
+      transform(declarations, filter: config.include);
   final wrapperCode = generate(
     transformedDeclarations,
     moduleName: sourceModule,

pkgs/swift2objc/lib/src/parser/parsers/parse_declarations.dart

@@ -25,6 +25,7 @@ List<Declaration> parseDeclarations(ParsedSymbolgraph symbolgraph) {
   return declarations.topLevelOnly;
 }
 
+// TODO(https://github.com/dart-lang/native/issues/1815): Support for extensions
 Declaration parseDeclaration(
   ParsedSymbol parsedSymbol,
   ParsedSymbolgraph symbolgraph,

pkgs/swift2objc/lib/src/transformer/_core/dependencies.dart

@@ -0,0 +1,259 @@
+import '../../ast/_core/interfaces/declaration.dart';
+import '../../ast/_core/interfaces/enum_declaration.dart';
+import '../../ast/_core/interfaces/function_declaration.dart';
+import '../../ast/_core/interfaces/variable_declaration.dart';
+import '../../ast/_core/shared/parameter.dart';
+import '../../ast/_core/shared/referred_type.dart';
+import '../../ast/declarations/compounds/class_declaration.dart';
+import '../../ast/declarations/compounds/members/initializer_declaration.dart';
+import '../../ast/declarations/compounds/protocol_declaration.dart';
+import '../../ast/declarations/compounds/struct_declaration.dart';
+
+// TODO(https://github.com/dart-lang/native/issues/1814): Type restrictions have not yet been implemented in system
+class DependencyVisitor {
+  final Iterable<Declaration> declarations;
+  Set<Declaration> visitedDeclarations = {};
+
+  DependencyVisitor(this.declarations);
+
+  Set<Declaration> visit(Declaration dec) {
+    final dependencies = <Declaration>{};
+
+    Iterable<Declaration> d = [dec];
+
+    while (true) {
+      final deps = d.fold<Set<String>>(
+          {}, (previous, element) => previous.union(visitDeclaration(element)));
+      final depDecls = declarations.where((d) => deps.contains(d.id));
+      if (depDecls.isEmpty ||
+          (dependencies.union(depDecls.toSet()).length) ==
+              dependencies.length) {
+        break;
+      } else {
+        dependencies.addAll(depDecls);
+        d = depDecls;
+      }
+    }
+
+    visitedDeclarations.addAll(dependencies);
+
+    return dependencies;
+  }
+
+  Set<String> visitDeclaration(Declaration decl, [Set<String>? context]) {
+    final cont = context ??= {};
+
+    // switch between declarations
+    if (decl is ClassDeclaration) {
+      visitClass(decl, cont);
+    } else if (decl is ProtocolDeclaration) {
+      visitProtocol(decl, cont);
+    } else if (decl is StructDeclaration) {
+      visitStruct(decl, cont);
+    } else if (decl is FunctionDeclaration) {
+      visitFunction(decl, cont);
+    } else if (decl is VariableDeclaration) {
+      visitVariable(decl, cont);
+    } else if (decl is EnumDeclaration) {
+      visitEnum(decl, cont);
+    }
+
+    return cont;
+  }
+
+  Set<String> visitEnum(EnumDeclaration decl, [Set<String>? context]) {
+    final cont = context ??= {};
+
+    // visit nested declarations
+    for (var n in decl.nestedDeclarations) {
+      visitDeclaration(n, cont);
+    }
+
+    // visit protocols
+    for (var p in decl.conformedProtocols) {
+      visitProtocol(p.declaration, cont);
+    }
+
+    // ensure generic types do not enter
+    cont.removeWhere(
+        (t) => decl.typeParams.map((type) => type.name).contains(t));
+
+    return cont;
+  }
+
+  Set<String> visitStruct(StructDeclaration decl, [Set<String>? context]) {
+    final cont = context ??= {};
+
+    // visit variables
+    for (var d in decl.properties) {
+      visitVariable(d, cont);
+    }
+
+    // visit methods
+    for (var m in decl.methods) {
+      visitFunction(m, cont);
+    }
+
+    // visit initializers
+    for (var i in decl.initializers) {
+      visitInitializer(i, cont);
+    }
+
+    // visit nested declarations
+    for (var n in decl.nestedDeclarations) {
+      visitDeclaration(n, cont);
+    }
+
+    // visit protocols
+    for (var p in decl.conformedProtocols) {
+      visitProtocol(p.declaration, cont);
+    }
+
+    // ensure generic types do not enter
+    cont.removeWhere(
+        (t) => decl.typeParams.map((type) => type.name).contains(t));
+
+    return cont;
+  }
+
+  Set<String> visitClass(ClassDeclaration decl, [Set<String>? context]) {
+    final cont = context ??= {};
+
+    // visit variables
+    for (var d in decl.properties) {
+      visitVariable(d, cont);
+    }
+
+    // visit methods
+    for (var m in decl.methods) {
+      visitFunction(m, cont);
+    }
+
+    // visit initializers
+    for (var i in decl.initializers) {
+      visitInitializer(i, cont);
+    }
+
+    // visit super if any
+    if (decl.superClass != null) {
+      visitDeclaration(decl.superClass!.declaration, cont);
+    }
+
+    // visit nested declarations
+    for (var n in decl.nestedDeclarations) {
+      visitDeclaration(n, cont);
+    }
+
+    // visit protocols
+    for (var p in decl.conformedProtocols) {
+      visitProtocol(p.declaration, cont);
+    }
+
+    // ensure generic types do not enter
+    cont.removeWhere(
+        (t) => decl.typeParams.map((type) => type.name).contains(t));
+
+    return cont;
+  }
+
+  Set<String> visitProtocol(ProtocolDeclaration decl, [Set<String>? context]) {
+    final cont = context ??= {};
+
+    // visit variables
+    for (var d in decl.properties) {
+      visitVariable(d, cont);
+    }
+
+    // visit methods
+    for (var m in decl.methods) {
+      visitFunction(m, cont);
+    }
+
+    // visit initializers
+    for (var i in decl.initializers) {
+      visitInitializer(i, cont);
+    }
+
+    // visit nested declarations
+    for (var n in decl.nestedDeclarations) {
+      visitDeclaration(n, cont);
+    }
+
+    // visit protocols
+    for (var p in decl.conformedProtocols) {
+      visitProtocol(p.declaration, cont);
+    }
+
+    // ensure generic types do not enter
+    cont.removeWhere(
+        (t) => decl.typeParams.map((type) => type.name).contains(t));
+
+    return cont;
+  }
+
+  Set<String> visitInitializer(InitializerDeclaration decl,
+      [Set<String>? context]) {
+    final cont = context ??= {};
+
+    // similar to `visitMethod`, except no return type
+    for (var p in decl.params) {
+      visitParameter(p, cont);
+    }
+
+    return cont;
+  }
+
+  Set<String> visitFunction(FunctionDeclaration decl, [Set<String>? context]) {
+    final cont = context ??= {};
+
+    // visit parameters
+    for (var p in decl.params) {
+      visitParameter(p, cont);
+    }
+
+    // ensure generic types do not enter
+    cont.removeWhere(
+        (t) => decl.typeParams.map((type) => type.name).contains(t));
+
+    // visit return type
+    visitType(decl.returnType, cont);
+
+    return cont;
+  }
+
+  Set<String> visitParameter(Parameter decl, [Set<String>? context]) {
+    final cont = context ??= {};
+
+    // just visit type of parameter
+    visitType(decl.type, cont);
+
+    return cont;
+  }
+
+  Set<String> visitVariable(VariableDeclaration decl, [Set<String>? context]) {
+    final cont = context ??= {};
+
+    // just return property type
+    visitType(decl.type, cont);
+
+    return cont;
+  }
+
+  Set<String> visitType(ReferredType type, [Set<String>? context]) {
+    final cont = context ??= {};
+
+    // we need to confirm the types located
+    // check what kind of type [type] is
+    switch (type) {
+      case DeclaredType():
+        cont.add(type.id);
+        break;
+      case GenericType():
+        // do nothing
+        break;
+      case OptionalType():
+        visitType(type.child, cont);
+    }
+    return cont;
+  }
+}

pkgs/swift2objc/lib/src/transformer/transform.dart

@@ -8,24 +8,40 @@ import '../ast/_core/interfaces/nestable_declaration.dart';
 import '../ast/declarations/compounds/class_declaration.dart';
 import '../ast/declarations/compounds/struct_declaration.dart';
 import '../ast/declarations/globals/globals.dart';
+import '_core/dependencies.dart';
 import '_core/unique_namer.dart';
 import 'transformers/transform_compound.dart';
 import 'transformers/transform_globals.dart';
 
 typedef TransformationMap = Map<Declaration, Declaration>;
 
-List<Declaration> transform(List<Declaration> declarations) {
+Set<Declaration> generateDependencies(
+    Iterable<Declaration> decls, Iterable<Declaration> allDecls) {
+  final visitor = DependencyVisitor(allDecls);
+  for (final dec in decls) {
+    visitor.visit(dec);
+  }
+
+  return visitor.visitedDeclarations;
+}
+
+/// Transforms the given declarations into the desired ObjC wrapped declarations
+List<Declaration> transform(List<Declaration> declarations,
+    {required bool Function(Declaration) filter}) {
   final transformationMap = <Declaration, Declaration>{};
 
+  final declarations0 = declarations.where(filter).toSet();
+  declarations0.addAll(generateDependencies(declarations0, declarations));
+
   final globalNamer = UniqueNamer(
-    declarations.map((declaration) => declaration.name),
+    declarations0.map((declaration) => declaration.name),
   );
 
   final globals = Globals(
-    functions: declarations.whereType<GlobalFunctionDeclaration>().toList(),
-    variables: declarations.whereType<GlobalVariableDeclaration>().toList(),
+    functions: declarations0.whereType<GlobalFunctionDeclaration>().toList(),
+    variables: declarations0.whereType<GlobalVariableDeclaration>().toList(),
   );
-  final nonGlobals = declarations
+  final nonGlobals = declarations0
       .where(
         (declaration) =>
             declaration is! GlobalFunctionDeclaration &&