001: /**
002: * Speedo: an implementation of JDO compliant personality on top of JORM generic
003: * I/O sub-system.
004: * Copyright (C) 2001-2005 France Telecom R&D
005: *
006: * This library is free software; you can redistribute it and/or
007: * modify it under the terms of the GNU Lesser General Public
008: * License as published by the Free Software Foundation; either
009: * version 2 of the License, or (at your option) any later version.
010: *
011: * This library is distributed in the hope that it will be useful,
012: * but WITHOUT ANY WARRANTY; without even the implied warranty of
013: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014: * Lesser General Public License for more details.
015: *
016: * You should have received a copy of the GNU Lesser General Public
017: * License along with this library; if not, write to the Free Software
018: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
019: *
020: *
021: *
022: * Contact: speedo@objectweb.org
023: *
024: * Authors: S.Chassande-Barrioz.
025: *
026: */package org.objectweb.speedo.generation.enhancer.common;
027:
028: import org.objectweb.asm.Attribute;
029: import org.objectweb.asm.ClassVisitor;
030: import org.objectweb.asm.CodeAdapter;
031: import org.objectweb.asm.CodeVisitor;
032: import org.objectweb.asm.Constants;
033: import org.objectweb.speedo.lib.Personality;
034: import org.objectweb.util.monolog.api.BasicLevel;
035: import org.objectweb.util.monolog.api.Logger;
036:
037: import java.util.ArrayList;
038: import java.util.List;
039:
040: /**
041: * ASM visitor cleaning a visited class to merge to another:
042: * <ul>
043: * <li>keep only one "class$" method</li>
044: * <li>rename a static section in order to agregate all at the end</li>
045: * <li>do not merge abstract method</li>
046: * <li>do not merge constructor</li>
047: * <li>do not merge this method</li>
048: * </ul>
049: *
050: * @author S.Chassande-Barrioz
051: */
052: public class MergedClassModifier extends LoggedClassAdapter {
053: private String classToWrite;
054: private String oldClass;
055: boolean hasDotClassMethod;
056: List methodNames;
057:
058: /**
059: * Builds the visitor
060: *
061: * @param classtowrite
062: * is the final name of the class to write
063: * @param oldclassName is the old name of the class.
064: */
065: public MergedClassModifier(final ClassVisitor classVisitor,
066: final String classtowrite, final String oldclassName,
067: final Logger logger, final Personality p) {
068: super (classVisitor, p, logger);
069: this .classToWrite = getJVMClassName(classtowrite);
070: this .oldClass = getJVMClassName(oldclassName);
071: this .methodNames = new ArrayList();
072: }
073:
074: // IMPLEMENTATION OF THE ClassVisitor INTERFACE //
075: // ---------------------------------------------//
076:
077: public CodeVisitor visitMethod(final int access, final String name,
078: final String desc, final String[] exceptions,
079: final Attribute attrs) {
080: String mn = name;
081: if ("class$".equals(name)) {
082: // keep only one "class$" method
083: if (hasDotClassMethod) {
084: // remove useless .class static method
085: return null;
086: } else {
087: // First .class static method
088: hasDotClassMethod = true;
089: }
090: } else if ("<clinit>".equals(name)) {
091: // rename a static section in order to agregate all at the end
092: mn = "clinit$" + methodNames.size();
093: methodNames.add(mn);
094: if (debug) {
095: logger.log(BasicLevel.DEBUG,
096: "rename a static section to " + mn);
097: }
098: } else if ((access & Constants.ACC_ABSTRACT) != 0) {
099: // do not merge abstract method
100: return null;
101: } else if (name.equals("<init>")) {
102: // do not merge constructor
103: return null;
104: } else if (name.equals("this")) {
105: // do not merge this method
106: return null;
107: }
108: //Modifies instructions that reference the old class.
109: CodeVisitor mv = cv.visitMethod(access, mn, desc, exceptions,
110: attrs);
111: if (mv != null) {
112: mv = new CodeRenamer(mv, oldClass, classToWrite);
113: }
114: return mv;
115: }
116:
117: public void visitEnd() {
118: // Merge the static initializer
119: if (methodNames.size() > 0) {
120: CodeVisitor mv = this .cv.visitMethod(Constants.ACC_STATIC,
121: "<clinit>", "()V", null, null);
122: for (int i = 0; i < methodNames.size(); i++) {
123: String methodName = (String) methodNames.get(i);
124: mv.visitMethodInsn(Constants.INVOKESTATIC,
125: classToWrite, methodName, "()V");
126: }
127: mv.visitInsn(Constants.RETURN);
128: }
129: super.visitEnd();
130: }
131:
132: }
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