001/**
002 * Logback: the reliable, generic, fast and flexible logging framework.
003 * Copyright (C) 1999-2025, QOS.ch. All rights reserved.
004 *
005 * This program and the accompanying materials are dual-licensed under
006 * either the terms of the Eclipse Public License v1.0 as published by
007 * the Eclipse Foundation
008 *
009 *   or (per the licensee's choosing)
010 *
011 * under the terms of the GNU Lesser General Public License version 2.1
012 * as published by the Free Software Foundation.
013 */
014package ch.qos.logback.core.model.processor.conditional;
015
016import ch.qos.logback.core.util.EnvUtil;
017import ch.qos.logback.core.util.OptionHelper;
018import ch.qos.logback.core.Context;
019import ch.qos.logback.core.CoreConstants;
020import ch.qos.logback.core.joran.conditional.Condition;
021import ch.qos.logback.core.joran.conditional.PropertyEvalScriptBuilder;
022import ch.qos.logback.core.model.Model;
023import ch.qos.logback.core.model.conditional.IfModel;
024import ch.qos.logback.core.model.conditional.IfModel.BranchState;
025import ch.qos.logback.core.model.processor.ModelHandlerBase;
026import ch.qos.logback.core.model.processor.ModelHandlerException;
027import ch.qos.logback.core.model.processor.ModelInterpretationContext;
028import ch.qos.logback.core.spi.ScanException;
029
030public class IfModelHandler extends ModelHandlerBase {
031
032
033    public static final String MISSING_JANINO_MSG = "Could not find Janino library on the class path. Skipping conditional processing.";
034    public static final String MISSING_JANINO_SEE = "See also " + CoreConstants.CODES_URL + "#ifJanino";
035
036    public static final String NEW_OPERATOR_DISALLOWED_MSG = "The 'condition' attribute may not contain the 'new' operator.";
037    public static final String NEW_OPERATOR_DISALLOWED_SEE = "See also " + CoreConstants.CODES_URL + "#conditionNew";
038
039    enum Branch {IF_BRANCH, ELSE_BRANCH; }
040    
041    IfModel ifModel = null;
042    
043    public IfModelHandler(Context context) {
044        super(context);
045    }
046
047    static public ModelHandlerBase makeInstance(Context context, ModelInterpretationContext ic) {
048        return new IfModelHandler(context);
049    }
050
051    @Override
052    protected Class<IfModel> getSupportedModelClass() {
053        return IfModel.class;
054    }
055    
056    @Override
057    public void handle(ModelInterpretationContext mic, Model model) throws ModelHandlerException {
058        
059        ifModel = (IfModel) model;
060        
061        if (!EnvUtil.isJaninoAvailable()) {
062            addError(MISSING_JANINO_MSG);
063            addError(MISSING_JANINO_SEE);
064            return;
065        }
066        
067        mic.pushModel(ifModel);
068        Condition condition = null;
069        int lineNum = model.getLineNumber();
070
071        String conditionStr = ifModel.getCondition();
072        if (!OptionHelper.isNullOrEmptyOrAllSpaces(conditionStr)) {
073            try {
074                conditionStr = OptionHelper.substVars(conditionStr, mic, context);
075            } catch (ScanException e) {
076               addError("Failed to parse input [" + conditionStr + "] on line "+lineNum, e);
077               ifModel.setBranchState(BranchState.IN_ERROR);
078               return;
079            }
080
081            // do not allow 'new' operator
082            if(hasNew(conditionStr)) {
083                addError(NEW_OPERATOR_DISALLOWED_MSG);
084                addError(NEW_OPERATOR_DISALLOWED_SEE);
085                return;
086            }
087
088            try {
089                PropertyEvalScriptBuilder pesb = new PropertyEvalScriptBuilder(mic);
090                pesb.setContext(context);
091                condition = pesb.build(conditionStr);
092            } catch (Exception|NoClassDefFoundError e) {
093                ifModel.setBranchState(BranchState.IN_ERROR);
094                addError("Failed to parse condition [" + conditionStr + "] on line "+lineNum, e);
095                return;
096            }
097
098            if (condition != null) {
099                boolean boolResult = condition.evaluate();
100                addInfo("Condition ["+conditionStr+"] evaluated to "+boolResult+ " on line "+lineNum);
101                ifModel.setBranchState(boolResult);
102            } else {
103                addError("The condition variable is null. This should not occur.");
104                ifModel.setBranchState(BranchState.IN_ERROR);
105                return;
106            }
107        }
108    }
109
110    private boolean hasNew(String conditionStr) {
111        return conditionStr.contains("new ");
112    }
113
114
115    @Override
116    public void postHandle(ModelInterpretationContext mic, Model model) throws ModelHandlerException {
117
118        if(mic.isModelStackEmpty()) {
119            addError("Unexpected unexpected empty model stack.");
120            return;
121        }
122
123        Object o = mic.peekModel();
124        if (o != ifModel) {
125            addWarn("The object [" + o + "] on the top the of the stack is not the expected [" + ifModel);
126        } else {
127            mic.popModel();
128        }
129    }
130
131}