001/** 002 * 003 * Copyright (c) 2014, the Railo Company Ltd. All rights reserved. 004 * 005 * This library is free software; you can redistribute it and/or 006 * modify it under the terms of the GNU Lesser General Public 007 * License as published by the Free Software Foundation; either 008 * version 2.1 of the License, or (at your option) any later version. 009 * 010 * This library is distributed in the hope that it will be useful, 011 * but WITHOUT ANY WARRANTY; without even the implied warranty of 012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 013 * Lesser General Public License for more details. 014 * 015 * You should have received a copy of the GNU Lesser General Public 016 * License along with this library. If not, see <http://www.gnu.org/licenses/>. 017 * 018 **/ 019package lucee.transformer.bytecode.expression; 020 021import lucee.transformer.bytecode.BytecodeContext; 022import lucee.transformer.bytecode.BytecodeException; 023import lucee.transformer.bytecode.util.Types; 024 025import org.objectweb.asm.Label; 026import org.objectweb.asm.Opcodes; 027import org.objectweb.asm.Type; 028import org.objectweb.asm.commons.GeneratorAdapter; 029 030public class FailSafeExpression extends ExpressionBase implements Opcodes { 031 032 private Expression expr; 033 private Expression defaultValue; 034 035 036 037 public FailSafeExpression(Expression expr,Expression defaultValue) { 038 super(expr.getStart(), expr.getEnd()); 039 this.expr=expr; 040 this.defaultValue=defaultValue; 041 } 042 043 044 045 @Override 046 public Type _writeOut(BytecodeContext bc, int mode) throws BytecodeException { 047 GeneratorAdapter mv = bc.getAdapter(); 048 049 int local = mv.newLocal(Types.OBJECT); 050 051 052 053 { 054 Label begin = new Label(); 055 Label onSuccess = new Label(); 056 Label onFail = new Label(); 057 Label end = new Label(); 058 059 mv.visitTryCatchBlock(begin, onSuccess, onFail, "java/lang/Throwable"); 060 mv.visitLabel(begin); 061 062 expr.writeOut(bc, MODE_REF); 063 mv.storeLocal(local); 064 065 mv.visitLabel(onSuccess); 066 mv.visitJumpInsn(GOTO, end); 067 068 mv.visitLabel(onFail); 069 //mv.visitVarInsn(ASTORE, 2); 070 071 defaultValue.writeOut(bc, MODE_REF); 072 mv.storeLocal(local); 073 074 075 mv.visitLabel(end); 076 mv.loadLocal(local); 077 078 //mv.visitLocalVariable("e", "Ljava/lang/Throwable;", null, l4, l3, 3); 079 080 081 } 082 083 084 085 return Types.OBJECT; 086 } 087 088}