maven-core/src/main/java/org/apache/maven/plugin/PluginParameterExpressionEvaluator.java

package org.apache.maven.plugin;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

import java.io.File;
import java.util.Properties;

import org.apache.maven.execution.MavenSession;
import org.apache.maven.plugin.descriptor.MojoDescriptor;
import org.apache.maven.plugin.descriptor.PluginDescriptor;
import org.apache.maven.project.MavenProject;
import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluationException;
import org.codehaus.plexus.component.configurator.expression.TypeAwareExpressionEvaluator;
import org.codehaus.plexus.util.introspection.ReflectionValueExtractor;

/**
 * Evaluator for plugin parameters expressions. Content surrounded by <code>${</code> and <code>}</code> is evaluated.
 * Recognized values are:
 * <table border="1">
 * <caption>Expression matrix</caption>
 * <tr><th>expression</th>                     <th></th>               <th>evaluation result</th></tr>
 * <tr><td><code>session</code></td>           <td></td>               <td>the actual {@link MavenSession}</td></tr>
 * <tr><td><code>session.*</code></td>         <td>(since Maven 3)</td><td></td></tr>
 * <tr><td><code>localRepository</code></td>   <td></td>
 *                                             <td>{@link MavenSession#getLocalRepository()}</td></tr>
 * <tr><td><code>reactorProjects</code></td>   <td></td>               <td>{@link MavenSession#getProjects()}</td></tr>
 * <tr><td><code>repositorySystemSession</code></td><td> (since Maven 3)</td>
 *                                             <td>{@link MavenSession#getRepositorySession()}</td></tr>
 * <tr><td><code>project</code></td>           <td></td>
 *                                             <td>{@link MavenSession#getCurrentProject()}</td></tr>
 * <tr><td><code>project.*</code></td>         <td></td>               <td></td></tr>
 * <tr><td><code>pom.*</code></td>             <td>(since Maven 3)</td><td>same as <code>project.*</code></td></tr>
 * <tr><td><code>executedProject</code></td>   <td></td>
 *                                             <td>{@link MavenProject#getExecutionProject()}</td></tr>
 * <tr><td><code>settings</code></td>          <td></td>               <td>{@link MavenSession#getSettings()}</td></tr>
 * <tr><td><code>settings.*</code></td>        <td></td>               <td></td></tr>
 * <tr><td><code>basedir</code></td>           <td></td>
 *                                             <td>{@link MavenSession#getExecutionRootDirectory()} or
 *                                                 <code>System.getProperty( "user.dir" )</code> if null</td></tr>
 * <tr><td><code>mojoExecution</code></td>     <td></td>               <td>the actual {@link MojoExecution}</td></tr>
 * <tr><td><code>mojo</code></td>              <td>(since Maven 3)</td><td>same as <code>mojoExecution</code></td></tr>
 * <tr><td><code>mojo.*</code></td>            <td>(since Maven 3)</td><td></td></tr>
 * <tr><td><code>plugin</code></td>            <td>(since Maven 3)</td>
 *                             <td>{@link MojoExecution#getMojoDescriptor()}.{@link MojoDescriptor#getPluginDescriptor()
 *                                 getPluginDescriptor()}</td></tr>
 * <tr><td><code>plugin.*</code></td>          <td></td>               <td></td></tr>
 * <tr><td><code>*</code></td>                 <td></td>               <td>system properties</td></tr>
 * <tr><td><code>*</code></td>                 <td></td>               <td>project properties</td></tr>
 * </table>
 * <i>Notice:</i> <code>reports</code> was supported in Maven 2.x but was removed in Maven 3
 *
 * @author Jason van Zyl
 * @see MavenSession
 * @see MojoExecution
 */
public class PluginParameterExpressionEvaluator
    implements TypeAwareExpressionEvaluator
{
    private MavenSession session;

    private MojoExecution mojoExecution;

    private MavenProject project;

    private String basedir;

    private Properties properties;

    public PluginParameterExpressionEvaluator( MavenSession session )
    {
        this( session, null );
    }

    public PluginParameterExpressionEvaluator( MavenSession session, MojoExecution mojoExecution )
    {
        this.session = session;
        this.mojoExecution = mojoExecution;
        this.properties = new Properties();
        this.project = session.getCurrentProject();

        //
        // Maven4: We may want to evaluate how this is used but we add these separate as the
        // getExecutionProperties is deprecated in MavenSession.
        //
        this.properties.putAll( session.getUserProperties() );
        this.properties.putAll( session.getSystemProperties() );

        String basedir = null;

        if ( project != null )
        {
            File projectFile = project.getBasedir();

            // this should always be the case for non-super POM instances...
            if ( projectFile != null )
            {
                basedir = projectFile.getAbsolutePath();
            }
        }

        if ( basedir == null )
        {
            basedir = session.getExecutionRootDirectory();
        }

        if ( basedir == null )
        {
            basedir = System.getProperty( "user.dir" );
        }

        this.basedir = basedir;
    }

    @Override
    public Object evaluate( String expr )
        throws ExpressionEvaluationException
    {
        return evaluate( expr, null );
    }

    @Override
    @SuppressWarnings( "checkstyle:methodlength" )
    public Object evaluate( String expr, Class<?> type )
        throws ExpressionEvaluationException
    {
        Object value = null;

        if ( expr == null )
        {
            return null;
        }

        String expression = stripTokens( expr );
        if ( expression.equals( expr ) )
        {
            int index = expr.indexOf( "${" );
            if ( index >= 0 )
            {
                int lastIndex = expr.indexOf( '}', index );
                if ( lastIndex >= 0 )
                {
                    String retVal = expr.substring( 0, index );

                    if ( ( index > 0 ) && ( expr.charAt( index - 1 ) == '$' ) )
                    {
                        retVal += expr.substring( index + 1, lastIndex + 1 );
                    }
                    else
                    {
                        Object subResult = evaluate( expr.substring( index, lastIndex + 1 ) );

                        if ( subResult != null )
                        {
                            retVal += subResult;
                        }
                        else
                        {
                            retVal += "$" + expr.substring( index + 1, lastIndex + 1 );
                        }
                    }

                    retVal += evaluate( expr.substring( lastIndex + 1 ) );
                    return retVal;
                }
            }

            // Was not an expression
            if ( expression.contains( "$$" ) )
            {
                return expression.replaceAll( "\\$\\$", "\\$" );
            }
            else
            {
                return expression;
            }
        }

        MojoDescriptor mojoDescriptor = mojoExecution.getMojoDescriptor();

        if ( "localRepository".equals( expression ) )
        {
            value = session.getLocalRepository();
        }
        else if ( "session".equals( expression ) )
        {
            value = session;
        }
        else if ( expression.startsWith( "session" ) )
        {
            try
            {
                int pathSeparator = expression.indexOf( '/' );

                if ( pathSeparator > 0 )
                {
                    String pathExpression = expression.substring( 1, pathSeparator );
                    value = ReflectionValueExtractor.evaluate( pathExpression, session );
                    value = value + expression.substring( pathSeparator );
                }
                else
                {
                    value = ReflectionValueExtractor.evaluate( expression.substring( 1 ), session );
                }
            }
            catch ( Exception e )
            {
                // TODO don't catch exception
                throw new ExpressionEvaluationException( "Error evaluating plugin parameter expression: " + expression,
                                                         e );
            }
        }
        else if ( "reactorProjects".equals( expression ) )
        {
            value = session.getProjects();
        }
        else if ( "mojoExecution".equals( expression ) )
        {
            value = mojoExecution;
        }
        else if ( "project".equals( expression ) )
        {
            value = project;
        }
        else if ( "executedProject".equals( expression ) )
        {
            value = project.getExecutionProject();
        }
        else if ( expression.startsWith( "project" ) || expression.startsWith( "pom" ) )
        {
            try
            {
                int pathSeparator = expression.indexOf( '/' );

                if ( pathSeparator > 0 )
                {
                    String pathExpression = expression.substring( 0, pathSeparator );
                    value = ReflectionValueExtractor.evaluate( pathExpression, project );
                    value = value + expression.substring( pathSeparator );
                }
                else
                {
                    value = ReflectionValueExtractor.evaluate( expression.substring( 1 ), project );
                }
            }
            catch ( Exception e )
            {
                // TODO don't catch exception
                throw new ExpressionEvaluationException( "Error evaluating plugin parameter expression: " + expression,
                                                         e );
            }
        }
        else if ( expression.equals( "repositorySystemSession" ) )
        {
            value = session.getRepositorySession();
        }
        else if ( expression.equals( "mojo" ) )
        {
            value = mojoExecution;
        }
        else if ( expression.startsWith( "mojo" ) )
        {
            try
            {
                int pathSeparator = expression.indexOf( '/' );

                if ( pathSeparator > 0 )
                {
                    String pathExpression = expression.substring( 1, pathSeparator );
                    value = ReflectionValueExtractor.evaluate( pathExpression, mojoExecution );
                    value = value + expression.substring( pathSeparator );
                }
                else
                {
                    value = ReflectionValueExtractor.evaluate( expression.substring( 1 ), mojoExecution );
                }
            }
            catch ( Exception e )
            {
                // TODO don't catch exception
                throw new ExpressionEvaluationException( "Error evaluating plugin parameter expression: " + expression,
                                                         e );
            }
        }
        else if ( expression.equals( "plugin" ) )
        {
            value = mojoDescriptor.getPluginDescriptor();
        }
        else if ( expression.startsWith( "plugin" ) )
        {
            try
            {
                int pathSeparator = expression.indexOf( '/' );

                PluginDescriptor pluginDescriptor = mojoDescriptor.getPluginDescriptor();

                if ( pathSeparator > 0 )
                {
                    String pathExpression = expression.substring( 1, pathSeparator );
                    value = ReflectionValueExtractor.evaluate( pathExpression, pluginDescriptor );
                    value = value + expression.substring( pathSeparator );
                }
                else
                {
                    value = ReflectionValueExtractor.evaluate( expression.substring( 1 ), pluginDescriptor );
                }
            }
            catch ( Exception e )
            {
                throw new ExpressionEvaluationException( "Error evaluating plugin parameter expression: " + expression,
                                                         e );
            }
        }
        else if ( "settings".equals( expression ) )
        {
            value = session.getSettings();
        }
        else if ( expression.startsWith( "settings" ) )
        {
            try
            {
                int pathSeparator = expression.indexOf( '/' );

                if ( pathSeparator > 0 )
                {
                    String pathExpression = expression.substring( 1, pathSeparator );
                    value = ReflectionValueExtractor.evaluate( pathExpression, session.getSettings() );
                    value = value + expression.substring( pathSeparator );
                }
                else
                {
                    value = ReflectionValueExtractor.evaluate( expression.substring( 1 ), session.getSettings() );
                }
            }
            catch ( Exception e )
            {
                // TODO don't catch exception
                throw new ExpressionEvaluationException( "Error evaluating plugin parameter expression: " + expression,
                                                         e );
            }
        }
        else if ( "basedir".equals( expression ) )
        {
            value = basedir;
        }
        else if ( expression.startsWith( "basedir" ) )
        {
            int pathSeparator = expression.indexOf( '/' );

            if ( pathSeparator > 0 )
            {
                value = basedir + expression.substring( pathSeparator );
            }
        }

        /*
         * MNG-4312: We neither have reserved all of the above magic expressions nor is their set fixed/well-known (it
         * gets occasionally extended by newer Maven versions). This imposes the risk for existing plugins to
         * unintentionally use such a magic expression for an ordinary system property. So here we check whether we
         * ended up with a magic value that is not compatible with the type of the configured mojo parameter (a string
         * could still be converted by the configurator so we leave those alone). If so, back off to evaluating the
         * expression from properties only.
         */
        if ( value != null && type != null && !( value instanceof String ) && !isTypeCompatible( type, value ) )
        {
            value = null;
        }

        if ( value == null )
        {
            // The CLI should win for defining properties

            if ( properties != null )
            {
                // We will attempt to get nab a system property as a way to specify a
                // parameter to a plugins. My particular case here is allowing the surefire
                // plugin to run a single test so I want to specify that class on the cli
                // as a parameter.

                value = properties.getProperty( expression );
            }

            if ( ( value == null ) && ( ( project != null ) && ( project.getProperties() != null ) ) )
            {
                value = project.getProperties().getProperty( expression );
            }

        }

        if ( value instanceof String )
        {
            // TODO without #, this could just be an evaluate call...

            String val = (String) value;

            int exprStartDelimiter = val.indexOf( "${" );

            if ( exprStartDelimiter >= 0 )
            {
                if ( exprStartDelimiter > 0 )
                {
                    value = val.substring( 0, exprStartDelimiter ) + evaluate( val.substring( exprStartDelimiter ) );
                }
                else
                {
                    value = evaluate( val.substring( exprStartDelimiter ) );
                }
            }
        }

        return value;
    }

    private static boolean isTypeCompatible( Class<?> type, Object value )
    {
        if ( type.isInstance( value ) )
        {
            return true;
        }
        // likely Boolean -> boolean, Short -> int etc. conversions, it's not the problem case we try to avoid
        return ( ( type.isPrimitive() || type.getName().startsWith( "java.lang." ) )
                        && value.getClass().getName().startsWith( "java.lang." ) );
    }

    private String stripTokens( String expr )
    {
        if ( expr.startsWith( "${" ) && ( expr.indexOf( '}' ) == expr.length() - 1 ) )
        {
            expr = expr.substring( 2, expr.length() - 1 );
        }
        return expr;
    }

    @Override
    public File alignToBaseDirectory( File file )
    {
        // TODO Copied from the DefaultInterpolator. We likely want to resurrect the PathTranslator or at least a
        // similar component for re-usage
        if ( file != null )
        {
            if ( file.isAbsolute() )
            {
                // path was already absolute, just normalize file separator and we're done
            }
            else if ( file.getPath().startsWith( File.separator ) )
            {
                // drive-relative Windows path, don't align with project directory but with drive root
                file = file.getAbsoluteFile();
            }
            else
            {
                // an ordinary relative path, align with project directory
                file = new File( new File( basedir, file.getPath() ).toURI().normalize() ).getAbsoluteFile();
            }
        }
        return file;
    }

}