| // Copyright 2014 The Bazel Authors. All rights reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| package com.google.devtools.build.lib.syntax; |
| |
| import com.google.common.base.Optional; |
| import com.google.devtools.build.lib.events.Location; |
| import com.google.devtools.build.lib.syntax.compiler.DebugInfo; |
| import com.google.devtools.build.lib.syntax.compiler.LoopLabels; |
| import com.google.devtools.build.lib.syntax.compiler.VariableScope; |
| |
| import net.bytebuddy.implementation.bytecode.ByteCodeAppender; |
| import net.bytebuddy.implementation.bytecode.member.MethodReturn; |
| |
| /** |
| * A wrapper Statement class for return expressions. |
| */ |
| public class ReturnStatement extends Statement { |
| |
| /** |
| * Exception sent by the return statement, to be caught by the function body. |
| */ |
| public class ReturnException extends EvalException { |
| Object value; |
| |
| public ReturnException(Location location, Object value) { |
| super(location, "Return statements must be inside a function"); |
| this.value = value; |
| } |
| |
| public Object getValue() { |
| return value; |
| } |
| |
| @Override |
| public boolean canBeAddedToStackTrace() { |
| return false; |
| } |
| } |
| |
| private final Expression returnExpression; |
| |
| public ReturnStatement(Expression returnExpression) { |
| this.returnExpression = returnExpression; |
| } |
| |
| @Override |
| void doExec(Environment env) throws EvalException, InterruptedException { |
| throw new ReturnException(returnExpression.getLocation(), returnExpression.eval(env)); |
| } |
| |
| Expression getReturnExpression() { |
| return returnExpression; |
| } |
| |
| @Override |
| public String toString() { |
| return "return " + returnExpression; |
| } |
| |
| @Override |
| public void accept(SyntaxTreeVisitor visitor) { |
| visitor.visit(this); |
| } |
| |
| @Override |
| void validate(ValidationEnvironment env) throws EvalException { |
| if (env.isTopLevel()) { |
| throw new EvalException(getLocation(), "Return statements must be inside a function"); |
| } |
| returnExpression.validate(env); |
| } |
| |
| @Override |
| ByteCodeAppender compile( |
| VariableScope scope, Optional<LoopLabels> loopLabels, DebugInfo debugInfo) |
| throws EvalException { |
| ByteCodeAppender compiledExpression = returnExpression.compile(scope, debugInfo); |
| return new ByteCodeAppender.Compound( |
| compiledExpression, new ByteCodeAppender.Simple(MethodReturn.REFERENCE)); |
| } |
| } |