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    1   /*
    2    $Id: ReflectorGenerator.java,v 1.12 2005/10/03 18:07:37 tug Exp $
    3
    4    Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
    5
    6    Redistribution and use of this software and associated documentation
    7    ("Software"), with or without modification, are permitted provided
    8    that the following conditions are met:
    9
    10   1. Redistributions of source code must retain copyright
    11      statements and notices.  Redistributions must also contain a
    12      copy of this document.
    13
    14   2. Redistributions in binary form must reproduce the
    15      above copyright notice, this list of conditions and the
    16      following disclaimer in the documentation and/or other
    17      materials provided with the distribution.
    18
    19   3. The name "groovy" must not be used to endorse or promote
    20      products derived from this Software without prior written
    21      permission of The Codehaus.  For written permission,
    22      please contact info@codehaus.org.
    23
    24   4. Products derived from this Software may not be called "groovy"
    25      nor may "groovy" appear in their names without prior written
    26      permission of The Codehaus. "groovy" is a registered
    27      trademark of The Codehaus.
    28
    29   5. Due credit should be given to The Codehaus -
    30      http://groovy.codehaus.org/
    31
    32   THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
    33   ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
    34   NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
    35   FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
    36   THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
    37   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
    38   (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    39   SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
    40   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
    41   STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
    42   ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
    43   OF THE POSSIBILITY OF SUCH DAMAGE.
    44
    45   */
    46  package org.codehaus.groovy.classgen;
    47
    48  import groovy.lang.MetaMethod;
    49
    50  import java.util.List;
    51
    52  import org.objectweb.asm.ClassVisitor;
    53  import org.objectweb.asm.MethodVisitor;
    54  import org.objectweb.asm.Opcodes;
    55  import org.objectweb.asm.Label;
    56
    57  /***
    58   * Code generates a Reflector
    59   *
    60   * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
    61   * @version $Revision: 1.12 $
    62   */
    63  public class ReflectorGenerator implements Opcodes {
    64
    65      private List methods;
    66      private ClassVisitor cw;
    67      private MethodVisitor cv;
    68      private BytecodeHelper helper = new BytecodeHelper(null);
    69      private String classInternalName;
    70
    71      public ReflectorGenerator(List methods) {
    72          this.methods = methods;
    73      }
    74
    75      public void generate(ClassVisitor cw, String className) {
    76          this.cw = cw;
    77
    78          classInternalName = BytecodeHelper.getClassInternalName(className);
    79          cw.visit(ClassGenerator.asmJDKVersion, ACC_PUBLIC + ACC_SUPER, classInternalName, (String)null, "org/codehaus/groovy/runtime/Reflector", null);
    80
    81          cv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
    82          cv.visitVarInsn(ALOAD, 0);
    83          cv.visitMethodInsn(INVOKESPECIAL, "org/codehaus/groovy/runtime/Reflector", "<init>", "()V");
    84          cv.visitInsn(RETURN);
    85          cv.visitMaxs(1, 1);
    86
    87          generateInvokeMethod();
    88
    89          cw.visitEnd();
    90      }
    91
    92      protected void generateInvokeMethod() {
    93          int methodCount = methods.size();
    94
    95          cv =
    96              cw.visitMethod(
    97                  ACC_PUBLIC,
    98                  "invoke",
    99                  "(Lgroovy/lang/MetaMethod;Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object;",
    100                 null,
    101                 null);
    102         helper = new BytecodeHelper(cv);
    103
    104         cv.visitVarInsn(ALOAD, 1);
    105         cv.visitMethodInsn(INVOKEVIRTUAL, "groovy/lang/MetaMethod", "getMethodIndex", "()I");
    106         Label defaultLabel = new Label();
    107         Label[] labels = new Label[methodCount];
    108         int[] indices = new int[methodCount];
    109         for (int i = 0; i < methodCount; i++) {
    110             labels[i] = new Label();
    111
    112             MetaMethod method = (MetaMethod) methods.get(i);
    113             method.setMethodIndex(i + 1);
    114             indices[i] = method.getMethodIndex();
    115
    116             //System.out.println("Index: " + method.getMethodIndex() + " for: " + method);
    117         }
    118
    119         cv.visitLookupSwitchInsn(defaultLabel, indices, labels);
    120         //cv.visitTableSwitchInsn(minMethodIndex, maxMethodIndex, defaultLabel, labels);
    121
    122         for (int i = 0; i < methodCount; i++) {
    123             cv.visitLabel(labels[i]);
    124
    125             MetaMethod method = (MetaMethod) methods.get(i);
    126             invokeMethod(method);
    127             if (method.getReturnType() == void.class) {
    128                 cv.visitInsn(ACONST_NULL);
    129             }
    130             cv.visitInsn(ARETURN);
    131         }
    132
    133         cv.visitLabel(defaultLabel);
    134         cv.visitVarInsn(ALOAD, 0);
    135         cv.visitVarInsn(ALOAD, 1);
    136         cv.visitVarInsn(ALOAD, 2);
    137         cv.visitVarInsn(ALOAD, 3);
    138         cv.visitMethodInsn(
    139             INVOKEVIRTUAL,
    140             classInternalName,
    141             "noSuchMethod",
    142             "(Lgroovy/lang/MetaMethod;Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object;");
    143         cv.visitInsn(ARETURN);
    144         cv.visitMaxs(4, 4);
    145     }
    146
    147     protected void invokeMethod(MetaMethod method) {
    148         /*** simple
    149         cv.visitVarInsn(ALOAD, 2);
    150         cv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "toString", "()Ljava/lang/String;");
    151         */
    152         Class ownerClass = method.getInterfaceClass();
    153         boolean useInterface = false;
    154         if (ownerClass == null) {
    155             ownerClass = method.getDeclaringClass();
    156         }
    157         else {
    158             useInterface = true;
    159         }
    160         String type = BytecodeHelper.getClassInternalName(ownerClass.getName());
    161         String descriptor = BytecodeHelper.getMethodDescriptor(method.getReturnType(), method.getParameterTypes());
    162
    163         //        System.out.println("Method: " + method);
    164         //        System.out.println("Descriptor: " + descriptor);
    165
    166         if (method.isStatic()) {
    167             loadParameters(method, 3);
    168             cv.visitMethodInsn(INVOKESTATIC, type, method.getName(), descriptor);
    169         }
    170         else {
    171             cv.visitVarInsn(ALOAD, 2);
    172             helper.doCast(ownerClass);
    173             loadParameters(method, 3);
    174             cv.visitMethodInsn((useInterface) ? INVOKEINTERFACE : INVOKEVIRTUAL, type, method.getName(), descriptor);
    175         }
    176
    177         helper.box(method.getReturnType());
    178     }
    179
    180     /*
    181     protected void generateInvokeSuperMethod() {
    182         List superMethods = new ArrayList(methods);
    183         for (Iterator iter = methods.iterator(); iter.hasNext();) {
    184             MetaMethod method = (MetaMethod) iter.next();
    185             if (!validSuperMethod(method)) {
    186                 superMethods.remove(method);
    187             }
    188         }
    189         int methodCount = superMethods.size();
    190         if (methodCount == 0) {
    191             return;
    192         }
    193         cv =
    194             cw.visitMethod(
    195                 ACC_PUBLIC,
    196                 "invokeSuper",
    197                 "(Lgroovy/lang/MetaMethod;Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object;",
    198                 null,
    199                 null);
    200         helper = new BytecodeHelper(cv);
    201
    202         cv.visitVarInsn(ALOAD, 1);
    203         cv.visitMethodInsn(INVOKEVIRTUAL, "groovy/lang/MetaMethod", "getMethodIndex", "()I");
    204         Label defaultLabel = new Label();
    205         Label[] labels = new Label[methodCount];
    206         int[] indices = new int[methodCount];
    207         for (int i = 0; i < methodCount; i++) {
    208             labels[i] = new Label();
    209
    210             MetaMethod method = (MetaMethod) superMethods.get(i);
    211             method.setMethodIndex(i + 1);
    212             indices[i] = method.getMethodIndex();
    213
    214             //System.out.println("Index: " + method.getMethodIndex() + " for: " + method);
    215         }
    216
    217         cv.visitLookupSwitchInsn(defaultLabel, indices, labels);
    218         //cv.visitTableSwitchInsn(minMethodIndex, maxMethodIndex, defaultLabel, labels);
    219
    220         for (int i = 0; i < methodCount; i++) {
    221             MetaMethod method = (MetaMethod) superMethods.get(i);
    222             cv.visitLabel(labels[i]);
    223
    224             invokeSuperMethod(method);
    225             if (method.getReturnType() == void.class) {
    226                 cv.visitInsn(ACONST_NULL);
    227             }
    228             cv.visitInsn(ARETURN);
    229         }
    230
    231         cv.visitLabel(defaultLabel);
    232         cv.visitVarInsn(ALOAD, 0);
    233         cv.visitVarInsn(ALOAD, 1);
    234         cv.visitVarInsn(ALOAD, 2);
    235         cv.visitVarInsn(ALOAD, 3);
    236         cv.visitMethodInsn(
    237             INVOKEVIRTUAL,
    238             classInternalName,
    239             "noSuchMethod",
    240             "(Lgroovy/lang/MetaMethod;Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object;");
    241         cv.visitInsn(ARETURN);
    242         cv.visitMaxs(4, 4);
    243     }
    244
    245     protected boolean validSuperMethod(MetaMethod method) {
    246         return !method.isStatic() && (method.getModifiers() & (Modifier.FINAL | Modifier.ABSTRACT)) == 0 && theClass == method.getDeclaringClass();
    247     }
    248
    249     protected void invokeSuperMethod(MetaMethod method) {
    250         Class ownerClass = method.getDeclaringClass();
    251         String type = helper.getClassInternalName(ownerClass.getName());
    252         String descriptor = helper.getMethodDescriptor(method.getReturnType(), method.getParameterTypes());
    253
    254 //        System.out.println("Method: " + method.getName());
    255 //        System.out.println("Descriptor: " + descriptor);
    256
    257         cv.visitVarInsn(ALOAD, 2);
    258         //helper.doCast(ownerClass);
    259         loadParameters(method, 3);
    260         cv.visitMethodInsn(INVOKESPECIAL, type, method.getName(), descriptor);
    261
    262         helper.box(method.getReturnType());
    263     }
    264 */
    265
    266     protected void loadParameters(MetaMethod method, int argumentIndex) {
    267         Class[] parameters = method.getParameterTypes();
    268         int size = parameters.length;
    269         for (int i = 0; i < size; i++) {
    270             cv.visitVarInsn(ALOAD, argumentIndex);
    271             helper.pushConstant(i);
    272             cv.visitInsn(AALOAD);
    273
    274             // we should cast to something
    275             Class type = parameters[i];
    276             if (type.isPrimitive()) {
    277                 helper.unbox(type);
    278             }
    279             else {
    280                 helper.doCast(type);
    281             }
    282         }
    283     }
    284 }