Groovy example source code file (InvocationWriter.java)

This example Groovy source code file (InvocationWriter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Groovy tags/keywords

argumentlistexpression, castexpression, classnode, constantexpression, expression, expression, methodcallermultiadapter, methodcallermultiadapter, methodcallexpression, string, string, tupleexpression, tupleexpression, util, variableexpression

The Groovy InvocationWriter.java source code

/*
 * Copyright 2003-2009 the original author or authors.
 *
 * 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 org.codehaus.groovy.classgen.asm;

import java.util.List;

import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.FieldNode;
import org.codehaus.groovy.ast.MethodNode;
import org.codehaus.groovy.ast.Parameter;
import org.codehaus.groovy.ast.expr.ArgumentListExpression;
import org.codehaus.groovy.ast.expr.CastExpression;
import org.codehaus.groovy.ast.expr.ClassExpression;
import org.codehaus.groovy.ast.expr.ConstantExpression;
import org.codehaus.groovy.ast.expr.Expression;
import org.codehaus.groovy.ast.expr.MethodCallExpression;
import org.codehaus.groovy.ast.expr.StaticMethodCallExpression;
import org.codehaus.groovy.ast.expr.TupleExpression;
import org.codehaus.groovy.ast.expr.VariableExpression;
import org.codehaus.groovy.classgen.AsmClassGenerator;
import org.codehaus.groovy.classgen.asm.OptimizingStatementWriter.StatementMeta;
import org.codehaus.groovy.runtime.ScriptBytecodeAdapter;
import org.objectweb.asm.MethodVisitor;

import static org.objectweb.asm.Opcodes.*;

public class InvocationWriter {
    // method invocation
    private static final MethodCallerMultiAdapter invokeMethodOnCurrent = MethodCallerMultiAdapter.newStatic(ScriptBytecodeAdapter.class, "invokeMethodOnCurrent", true, false);
    private static final MethodCallerMultiAdapter invokeMethodOnSuper = MethodCallerMultiAdapter.newStatic(ScriptBytecodeAdapter.class, "invokeMethodOnSuper", true, false);
    private static final MethodCallerMultiAdapter invokeMethod = MethodCallerMultiAdapter.newStatic(ScriptBytecodeAdapter.class, "invokeMethod", true, false);
    private static final MethodCallerMultiAdapter invokeStaticMethod = MethodCallerMultiAdapter.newStatic(ScriptBytecodeAdapter.class, "invokeStaticMethod", true, true);
    private static final MethodCaller invokeClosureMethod = MethodCaller.newStatic(ScriptBytecodeAdapter.class, "invokeClosure");

    private WriterController controller;
    
    public InvocationWriter(WriterController wc) {
        this.controller = wc;
    }

    private void makeInvokeMethodCall(MethodCallExpression call, boolean useSuper, MethodCallerMultiAdapter adapter) {
        // receiver
        // we operate on GroovyObject if possible
        Expression objectExpression = call.getObjectExpression();
        // message name
        Expression messageName = new CastExpression(ClassHelper.STRING_TYPE, call.getMethod());
        if (useSuper) {
            ClassNode classNode = controller.isInClosure() ? controller.getOutermostClass() : controller.getClassNode(); // GROOVY-4035 
            ClassNode superClass = classNode.getSuperClass();
            makeCall(call, new ClassExpression(superClass),
                    objectExpression, messageName,
                    call.getArguments(), adapter,
                    call.isSafe(), call.isSpreadSafe(),
                    false
            );
        } else {
            makeCall(call, objectExpression, messageName,
                    call.getArguments(), adapter,
                    call.isSafe(), call.isSpreadSafe(),
                    call.isImplicitThis()
            );
        }
    }
    
    public void makeCall(
            Expression origin,
            Expression receiver, Expression message, Expression arguments,
            MethodCallerMultiAdapter adapter,
            boolean safe, boolean spreadSafe, boolean implicitThis
    ) {
        ClassNode cn = controller.getClassNode();
        if (controller.isInClosure() && !implicitThis && AsmClassGenerator.isThisExpression(receiver)) cn=cn.getOuterClass();
        makeCall(origin, new ClassExpression(cn), receiver, message, arguments,
                adapter, safe, spreadSafe, implicitThis);
    }
    
    private boolean writeDirectMethodCall(MethodNode target, boolean implicitThis,  Expression receiver, TupleExpression args) {
        if (target==null) return false;
        
        String methodName = target.getName();
        CompileStack compileStack = controller.getCompileStack();
        OperandStack operandStack = controller.getOperandStack();
        
        MethodVisitor mv = controller.getMethodVisitor();
        int opcode = INVOKEVIRTUAL;
        if (target.isStatic()) {
            opcode = INVOKESTATIC;
        } else if (target.isPrivate()) {
            opcode = INVOKESPECIAL;
        }

        // handle receiver
        int argumentsToRemove = 0;
        if (opcode!=INVOKESTATIC) {
            if (receiver!=null) {
                // load receiver if not static invocation
                compileStack.pushImplicitThis(implicitThis);
                receiver.visit(controller.getAcg());
                operandStack.doGroovyCast(target.getDeclaringClass());
                compileStack.popImplicitThis();
                argumentsToRemove++;
            } else {
                mv.visitIntInsn(ALOAD,0);
            }
        }
        
        // load arguments
        Parameter[] para = target.getParameters();
        List<Expression> argumentList = args.getExpressions();
        for (int i=0; i<argumentList.size(); i++) {
            argumentList.get(i).visit(controller.getAcg());
            controller.getOperandStack().doGroovyCast(para[i].getType());
        }

        String owner = BytecodeHelper.getClassInternalName(target.getDeclaringClass());
        String desc = BytecodeHelper.getMethodDescriptor(target.getReturnType(), target.getParameters());
        mv.visitMethodInsn(opcode, owner, methodName, desc);
        ClassNode ret = target.getReturnType().redirect();
        if (ret==ClassHelper.VOID_TYPE) {
            ret = ClassHelper.OBJECT_TYPE;
            mv.visitInsn(ACONST_NULL);
        }
        argumentsToRemove += args.getExpressions().size();
        controller.getOperandStack().remove(argumentsToRemove);
        controller.getOperandStack().push(ret);
        return true;
    }

    private void makeCall(
            Expression origin, ClassExpression sender,
            Expression receiver, Expression message, Expression arguments,
            MethodCallerMultiAdapter adapter,
            boolean safe, boolean spreadSafe, boolean implicitThis
    ) { 
        // optimization path
        boolean fittingAdapter =    adapter == invokeMethodOnCurrent ||
                                    adapter == invokeStaticMethod;
        if (fittingAdapter && controller.optimizeForInt && controller.isFastPath()) {
            String methodName = getMethodName(message);
            if (methodName != null) {
                TupleExpression args;
                if (arguments instanceof TupleExpression) {
                    args = (TupleExpression) arguments;
                } else {
                    args = new TupleExpression(receiver);
                }

                StatementMeta meta = null;
                if (origin!=null) meta = (StatementMeta) origin.getNodeMetaData(StatementMeta.class);
                MethodNode mn = null;
                if (meta!=null) mn = meta.target;
                
                if (writeDirectMethodCall(mn, true, null, args)) return;                
            }
        }
        
        boolean containsSpreadExpression = AsmClassGenerator.containsSpreadExpression(arguments);
        if (!containsSpreadExpression && origin instanceof MethodCallExpression) {
            MethodCallExpression mce = (MethodCallExpression) origin;
            MethodNode target = mce.getMethodTarget();
            if (writeDirectMethodCall(target, implicitThis, receiver, makeArgumentList(arguments))) return;
        }
        
        // prepare call site
        if ((adapter == invokeMethod || adapter == invokeMethodOnCurrent || adapter == invokeStaticMethod) && !spreadSafe) {
            String methodName = getMethodName(message);

            if (methodName != null) {
                controller.getCallSiteWriter().makeCallSite(
                        receiver, methodName, arguments, safe, implicitThis, 
                        adapter == invokeMethodOnCurrent, 
                        adapter == invokeStaticMethod);
                return;
            }
        }

        OperandStack operandStack = controller.getOperandStack();
        CompileStack compileStack = controller.getCompileStack();
        AsmClassGenerator acg = controller.getAcg();
        
        // ensure VariableArguments are read, not stored
        compileStack.pushLHS(false);

        // sender only for call sites
        if (adapter == AsmClassGenerator.setProperty) {
            ConstantExpression.NULL.visit(acg);
        } else {
            sender.visit(acg);
        }
        
        // receiver
        compileStack.pushImplicitThis(implicitThis);
        receiver.visit(acg);
        operandStack.box();
        compileStack.popImplicitThis();
        
        
        int operandsToRemove = 2;
        // message
        if (message != null) {
            message.visit(acg);
            operandStack.box();
            operandsToRemove++;
        }

        // arguments
        int numberOfArguments = containsSpreadExpression ? -1 : AsmClassGenerator.argumentSize(arguments);
        if (numberOfArguments > MethodCallerMultiAdapter.MAX_ARGS || containsSpreadExpression) {
            ArgumentListExpression ae = makeArgumentList(arguments);
            if (containsSpreadExpression) {
                acg.despreadList(ae.getExpressions(), true);
            } else {
                ae.visit(acg);
            }
        } else if (numberOfArguments > 0) {
            operandsToRemove += numberOfArguments;
            TupleExpression te = (TupleExpression) arguments;
            for (int i = 0; i < numberOfArguments; i++) {
                Expression argument = te.getExpression(i);
                argument.visit(acg);
                operandStack.box();
                if (argument instanceof CastExpression) acg.loadWrapper(argument);
            }
        }

        adapter.call(controller.getMethodVisitor(), numberOfArguments, safe, spreadSafe);

        compileStack.popLHS();
        operandStack.replace(ClassHelper.OBJECT_TYPE,operandsToRemove);
    }

    private ArgumentListExpression makeArgumentList(Expression arguments) {
        ArgumentListExpression ae;
        if (arguments instanceof ArgumentListExpression) {
            ae = (ArgumentListExpression) arguments;
        } else if (arguments instanceof TupleExpression) {
            TupleExpression te = (TupleExpression) arguments;
            ae = new ArgumentListExpression(te.getExpressions());
        } else {
            ae = new ArgumentListExpression();
            ae.addExpression(arguments);
        }
        return ae;
    }

    private String getMethodName(Expression message) {
        String methodName = null;
        if (message instanceof CastExpression) {
            CastExpression msg = (CastExpression) message;
            if (msg.getType() == ClassHelper.STRING_TYPE) {
                final Expression methodExpr = msg.getExpression();
                if (methodExpr instanceof ConstantExpression)
                  methodName = methodExpr.getText();
            }
        }

        if (methodName == null && message instanceof ConstantExpression) {
            ConstantExpression constantExpression = (ConstantExpression) message;
            methodName = constantExpression.getText();
        }
        return methodName;
    }

    public void writeInvokeMethod(MethodCallExpression call) {
        if (isClosureCall(call)) {
            // let's invoke the closure method
            invokeClosure(call.getArguments(), call.getMethodAsString());
        } else {
            boolean isSuperMethodCall = usesSuper(call);
            MethodCallerMultiAdapter adapter = invokeMethod;
            if (AsmClassGenerator.isThisExpression(call.getObjectExpression())) adapter = invokeMethodOnCurrent;
            if (isSuperMethodCall) adapter = invokeMethodOnSuper;
            if (isStaticInvocation(call)) adapter = invokeStaticMethod;
            makeInvokeMethodCall(call, isSuperMethodCall, adapter);
        }
    }

    private boolean isClosureCall(MethodCallExpression call) {
        // are we a local variable?
        // it should not be an explicitly "this" qualified method call
        // and the current class should have a possible method
        ClassNode classNode = controller.getClassNode();
        String methodName = call.getMethodAsString();
        if (methodName==null) return false;
        if (!call.isImplicitThis()) return false;
        if (!AsmClassGenerator.isThisExpression(call.getObjectExpression())) return false;
        FieldNode field = classNode.getDeclaredField(methodName);
        if (field == null) return false;
        if (isStaticInvocation(call) && !field.isStatic()) return false;
        Expression arguments = call.getArguments();
        return ! classNode.hasPossibleMethod(methodName, arguments);
    }

    private void invokeClosure(Expression arguments, String methodName) {
        AsmClassGenerator acg = controller.getAcg();
        acg.visitVariableExpression(new VariableExpression(methodName));
        if (arguments instanceof TupleExpression) {
            arguments.visit(acg);
        } else {
            new TupleExpression(arguments).visit(acg);
        }
        invokeClosureMethod.call(controller.getMethodVisitor());
        controller.getOperandStack().replace(ClassHelper.OBJECT_TYPE);
    }

    private boolean isStaticInvocation(MethodCallExpression call) {
        if (!AsmClassGenerator.isThisExpression(call.getObjectExpression())) return false;
        if (controller.isStaticMethod()) return true;
        return controller.isStaticContext() && !call.isImplicitThis();
    }
    
    private static boolean usesSuper(MethodCallExpression call) {
        Expression expression = call.getObjectExpression();
        if (expression instanceof VariableExpression) {
            VariableExpression varExp = (VariableExpression) expression;
            String variable = varExp.getName();
            return variable.equals("super");
        }
        return false;
    }

    public void writeInvokeStaticMethod(StaticMethodCallExpression call) {
        makeCall(call,
                new ClassExpression(call.getOwnerType()),
                new ConstantExpression(call.getMethod()),
                call.getArguments(),
                InvocationWriter.invokeStaticMethod,
                false, false, false);
    }
}