Fasta kernel builders.

pkg/fasta/lib/src/kernel/kernel_procedure_builder.dart

+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library fasta.kernel_procedure_builder;
+
+import 'package:kernel/ast.dart' show
+    Arguments,
+    AsyncMarker,
+    Constructor,
+    DartType,
+    DynamicType,
+    EmptyStatement,
+    Expression,
+    FunctionNode,
+    Initializer,
+    Library,
+    LocalInitializer,
+    Member,
+    Name,
+    NamedExpression,
+    Procedure,
+    ProcedureKind,
+    RedirectingInitializer,
+    Statement,
+    SuperInitializer,
+    TypeParameter,
+    VariableDeclaration,
+    VariableGet,
+    VoidType,
+    setParents;
+
+import 'package:kernel/type_algebra.dart' show
+    containsTypeVariable,
+    substitute;
+
+import '../errors.dart' show
+    internalError;
+
+import '../modifier.dart' show
+    abstractMask;
+
+import 'kernel_builder.dart' show
+    ClassBuilder,
+    ConstructorReferenceBuilder,
+    FormalParameterBuilder,
+    KernelFormalParameterBuilder,
+    KernelTypeBuilder,
+    KernelTypeVariableBuilder,
+    MetadataBuilder,
+    ProcedureBuilder,
+    TypeBuilder,
+    TypeVariableBuilder,
+    memberError;
+
+abstract class KernelFunctionBuilder
+    extends ProcedureBuilder<KernelTypeBuilder> {
+  FunctionNode function;
+
+  Statement actualBody;
+
+  KernelFunctionBuilder(
+      List<MetadataBuilder> metadata,
+      int modifiers, KernelTypeBuilder returnType, String name,
+      List<TypeVariableBuilder> typeVariables,
+      List<FormalParameterBuilder> formals)
+      : super(metadata, modifiers, returnType, name, typeVariables, formals);
+
+  void set body(Statement newBody) {
+    if (isAbstract && newBody != null) {
+      return internalError("Attempting to set body on abstract method.");
+    }
+    actualBody = newBody;
+    if (function != null) {
+      function.body = newBody;
+      newBody?.parent = function;
+    }
+  }
+
+  Statement get body => actualBody ??= new EmptyStatement();
+
+  FunctionNode buildFunction() {
+    assert(function == null);
+    FunctionNode result = new FunctionNode(body, asyncMarker: asyncModifier);
+    if (typeVariables != null) {
+      for (KernelTypeVariableBuilder t in typeVariables) {
+        result.typeParameters.add(t.parameter);
+      }
+      setParents(result.typeParameters, result);
+    }
+    if (formals != null) {
+      for (KernelFormalParameterBuilder formal in formals) {
+        VariableDeclaration parameter = formal.build();
+        if (formal.isNamed) {
+          result.namedParameters.add(parameter);
+        } else {
+          result.positionalParameters.add(parameter);
+        }
+        parameter.parent = result;
+        if (formal.isRequired) {
+          result.requiredParameterCount++;
+        }
+      }
+    }
+    if (returnType != null) {
+      result.returnType = returnType.build();
+    }
+    if (!isConstructor && !isInstanceMember && parent is ClassBuilder) {
+      List<TypeParameter> typeParameters = parent.target.typeParameters;
+      if (typeParameters.isNotEmpty) {
+        Map<TypeParameter, DartType> substitution;
+        DartType removeTypeVariables(DartType type) {
+          if (substitution == null) {
+            substitution = <TypeParameter, DartType>{};
+            for (TypeParameter parameter in typeParameters) {
+              substitution[parameter] = const DynamicType();
+            }
+          }
+          print("Can only use type variables in instance methods.");
+          return substitute(type, substitution);
+        }
+        Set<TypeParameter> set = typeParameters.toSet();
+        for (VariableDeclaration parameter in result.positionalParameters) {
+          if (containsTypeVariable(parameter.type, set)) {
+            parameter.type = removeTypeVariables(parameter.type);
+          }
+        }
+        for (VariableDeclaration parameter in result.namedParameters) {
+          if (containsTypeVariable(parameter.type, set)) {
+            parameter.type = removeTypeVariables(parameter.type);
+          }
+        }
+        if (containsTypeVariable(result.returnType, set)) {
+          result.returnType = removeTypeVariables(result.returnType);
+        }
+      }
+    }
+    return function = result;
+  }
+
+  Member build(Library library);
+}
+
+class KernelProcedureBuilder extends KernelFunctionBuilder {
+  final Procedure procedure;
+
+  AsyncMarker actualAsyncModifier;
+
+  final ConstructorReferenceBuilder redirectionTarget;
+
+  KernelProcedureBuilder(
+      List<MetadataBuilder> metadata,
+      int modifiers, KernelTypeBuilder returnType, String name,
+      List<TypeVariableBuilder> typeVariables,
+      List<FormalParameterBuilder> formals, this.actualAsyncModifier,
+      ProcedureKind kind, [this.redirectionTarget])
+      : procedure = new Procedure(null, kind, null),
+        super(metadata, modifiers, returnType, name, typeVariables, formals);
+
+  ProcedureKind get kind => procedure.kind;
+
+  AsyncMarker get asyncModifier => actualAsyncModifier;
+
+  Statement get body {
+    if (actualBody == null && redirectionTarget == null && !isAbstract &&
+        !isExternal) {
+      actualBody = new EmptyStatement();
+    }
+    return actualBody;
+  }
+
+  void set asyncModifier(AsyncMarker newModifier) {
+    actualAsyncModifier = newModifier;
+    if (function != null) {
+      // No parent, it's an enum.
+      function.asyncMarker = actualAsyncModifier;
+    }
+  }
+
+  Procedure build(Library library) {
+    // TODO(ahe): I think we may call this twice on parts. Investigate.
+    if (procedure.name == null) {
+      procedure.function = buildFunction();
+      procedure.function.parent = procedure;
+      procedure.isAbstract = isAbstract;
+      procedure.isStatic = isStatic;
+      procedure.isExternal = isExternal;
+      procedure.isConst = isConst;
+      procedure.name = new Name(name, library);
+    }
+    return procedure;
+  }
+
+  KernelFunctionBuilder toConstructor(String name,
+      List<TypeVariableBuilder> classTypeVariables) {
+    assert(procedure.name == null);
+    assert(actualBody == null);
+    if (isFactory) {
+      if (this.typeVariables != null) {
+        return memberError(target, "Factories can't be generic.");
+      }
+      List<KernelTypeVariableBuilder> typeVariables;
+      KernelTypeBuilder returnType = this.returnType;
+      List<FormalParameterBuilder> formals;
+      if (classTypeVariables != null) {
+        typeVariables = <KernelTypeVariableBuilder>[];
+        for (KernelTypeVariableBuilder variable in classTypeVariables) {
+          typeVariables.add(new KernelTypeVariableBuilder(variable.name));
+        }
+        Map<TypeVariableBuilder, TypeBuilder> substitution =
+            <TypeVariableBuilder, TypeBuilder>{};
+        int i = 0;
+        for (KernelTypeVariableBuilder variable in classTypeVariables) {
+          substitution[variable] = typeVariables[i++].asTypeBuilder();
+        }
+        i = 0;
+        for (KernelTypeVariableBuilder variable in classTypeVariables) {
+          typeVariables[i++].bound = variable?.bound?.subst(substitution);
+        }
+        returnType = returnType?.subst(substitution);
+        i = 0;
+        if (this.formals != null) {
+          for (KernelFormalParameterBuilder formal in this.formals) {
+            KernelTypeBuilder type = formal.type?.subst(substitution);
+            if (type != formal.type) {
+              formals ??= this.formals.toList();
+              formals[i] = new KernelFormalParameterBuilder(formal.metadata,
+                  formal.modifiers, type, formal.name, formal.hasThis);
+            }
+            i++;
+          }
+        }
+      }
+      formals ??= this.formals;
+      return new KernelProcedureBuilder(
+          metadata, modifiers, returnType, name, typeVariables, formals,
+          actualAsyncModifier, kind, redirectionTarget)
+          ..parent = parent;
+    } else {
+      return new KernelConstructorBuilder(metadata, modifiers & ~abstractMask,
+          returnType, name, typeVariables, formals)
+          ..parent = parent;
+    }
+  }
+
+  Procedure get target => procedure;
+}
+
+// TODO(ahe): Move this to own file?
+class KernelConstructorBuilder extends KernelFunctionBuilder {
+  final Constructor constructor = new Constructor(null);
+
+  bool hasMovedSuperInitializer = false;
+
+  SuperInitializer superInitializer;
+
+  RedirectingInitializer redirectingInitializer;
+
+  KernelConstructorBuilder(
+      List<MetadataBuilder> metadata,
+      int modifiers, KernelTypeBuilder returnType, String name,
+      List<TypeVariableBuilder> typeVariables,
+      List<FormalParameterBuilder> formals)
+      : super(metadata, modifiers, returnType, name, typeVariables, formals);
+
+  bool get isInstanceMember => false;
+
+  bool get isConstructor => true;
+
+  AsyncMarker get asyncModifier => AsyncMarker.Sync;
+
+  ProcedureKind get kind => null;
+
+  Constructor build(Library library) {
+    if (constructor.name == null) {
+      constructor.function = buildFunction();
+      constructor.function.parent = constructor;
+      constructor.isConst = isConst;
+      constructor.isExternal = isExternal;
+      constructor.name = new Name(name, library);
+    }
+    return constructor;
+  }
+
+  FunctionNode buildFunction() {
+    // TODO(ahe): Should complain if another type is explicitly set.
+    return super.buildFunction()
+        ..returnType = const VoidType();
+  }
+
+  Constructor get target => constructor;
+
+  void checkSuperOrThisInitializer(Initializer initializer) {
+    if (superInitializer != null || redirectingInitializer != null) {
+      memberError(target,
+          "Can't have more than one 'super' or 'this' initializer.",
+          initializer.fileOffset);
+    }
+  }
+
+  void addInitializer(Initializer initializer) {
+    List<Initializer> initializers = constructor.initializers;
+    if (initializer is SuperInitializer) {
+      checkSuperOrThisInitializer(initializer);
+      superInitializer = initializer;
+    } else if (initializer is RedirectingInitializer) {
+      checkSuperOrThisInitializer(initializer);
+      redirectingInitializer = initializer;
+      if (constructor.initializers.isNotEmpty) {
+        memberError(target, "'this' initializer must be the only initializer.",
+            initializer.fileOffset);
+      }
+    } else if (redirectingInitializer != null) {
+      memberError(target, "'this' initializer must be the only initializer.",
+          initializer.fileOffset);
+    } else if (superInitializer != null && superInitializer != initializer) {
+      assert(initializers[initializers.length - 1] == superInitializer);

[Johnni Winther, 2017/01/18 12:42:40]

Add documentation for what this case is.

[ahe, 2017/01/18 15:21:50]

Done.

Writing the documentation made me realize a mistake, so the code was tweaked.

+      initializers[initializers.length - 1] = initializer..parent = constructor;
+      initializer = superInitializer;
+      if (!hasMovedSuperInitializer) {
+        hasMovedSuperInitializer = true;
+        Arguments arguments = superInitializer.arguments;
+        List<Expression> positional = arguments.positional;
+        for (int i = 0; i < positional.length; i++) {

[Johnni Winther, 2017/01/18 12:42:40]

Add documentation for what you are doing here and in the loop below.

[ahe, 2017/01/18 15:21:50]

Done.

+          VariableDeclaration variable =
+              new VariableDeclaration.forValue(positional[i], isFinal: true);
+          initializers.add(
+              new LocalInitializer(variable)..parent = constructor);
+          positional[i] = new VariableGet(variable)..parent = arguments;
+        }
+        for (NamedExpression named in arguments.named) {
+          VariableDeclaration variable =
+              new VariableDeclaration.forValue(named.value, isFinal: true);
+          named.value = new VariableGet(variable)..parent = named;
+          initializers.add(
+              new LocalInitializer(variable)..parent = constructor);
+        }
+      }
+    }
+    initializers.add(initializer);
+    initializer.parent = constructor;
+  }
+}