001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.exec.environment;
019
020import java.io.BufferedReader;
021import java.io.IOException;
022import java.util.HashMap;
023import java.util.Map;
024import java.util.TreeMap;
025
026import org.apache.commons.exec.CommandLine;
027import org.apache.commons.exec.OS;
028
029/**
030 * Helper class to determine the environment variable for the OS. Depending on the JDK the environment variables can be either retrieved directly from the JVM
031 * or requires starting a process to get them running an OS command line.
032 */
033public class DefaultProcessingEnvironment {
034
035    /** The environment variables of the process */
036    protected Map<String, String> procEnvironment;
037
038    /**
039     * Creates a map that obeys the casing rules of the current platform for key lookup. E.g. on a Windows platform, the map keys will be case-insensitive.
040     *
041     * @return The map for storage of environment variables, never {@code null}.
042     */
043    private Map<String, String> createEnvironmentMap() {
044        if (OS.isFamilyWindows()) {
045            return new TreeMap<>(String::compareToIgnoreCase);
046        }
047        return new HashMap<>();
048    }
049
050    /**
051     * Creates the list of environment variables for this process.
052     *
053     * @return a amp containing the environment variables.
054     * @throws IOException the operation failed.
055     */
056    protected Map<String, String> createProcEnvironment() throws IOException {
057        if (procEnvironment == null) {
058            procEnvironment = createEnvironmentMap();
059            procEnvironment.putAll(System.getenv());
060        }
061        return procEnvironment;
062    }
063
064    /**
065     * Determine the OS specific command line to get a list of environment variables.
066     *
067     * @return the command line.
068     * @deprecated No longer needed.
069     */
070    @Deprecated
071    protected CommandLine getProcEnvCommand() {
072//        String executable;
073//        String[] arguments = null;
074//        if (OS.isFamilyOS2()) {
075//            // OS/2 - use same mechanism as Windows 2000
076//            executable = "cmd";
077//
078//            arguments = new String[] {"/c", "set"};
079//        } else if (OS.isFamilyWindows()) {
080//            // Determine if we're running under XP/2000/NT or 98/95
081//            if (OS.isFamilyWin9x()) {
082//                executable = "command.com";
083//                // Windows 98/95
084//            } else {
085//                executable = "cmd";
086//                // Windows XP/2000/NT/2003
087//            }
088//            arguments = new String[] {"/c", "set"};
089//        } else if (OS.isFamilyZOS() || OS.isFamilyUnix()) {
090//            // On most systems one could use: /bin/sh -c env
091//
092//            // Some systems have /bin/env, others /usr/bin/env, just try
093//            if (new File("/bin/env").canRead()) {
094//                executable = "/bin/env";
095//            } else if (new File("/usr/bin/env").canRead()) {
096//                executable = "/usr/bin/env";
097//            } else {
098//                // rely on PATH
099//                executable = "env";
100//            }
101//        } else if (OS.isFamilyNetware() || OS.isFamilyOS400()) {
102//            // rely on PATH
103//            executable = "env";
104//        } else {
105//            // macOS 9 and previous
106//            // TODO: I have no idea how to get it, someone must fix it
107//            executable = null;
108//        }
109        final CommandLine commandLine = null;
110//        if (executable != null) {
111//            commandLine = new CommandLine(executable);
112//            commandLine.addArguments(arguments);
113//        }
114        return commandLine;
115    }
116
117    /**
118     * Gets the list of environment variables for this process.
119     *
120     * @return a map containing the environment variables.
121     * @throws IOException obtaining the environment variables failed.
122     */
123    public synchronized Map<String, String> getProcEnvironment() throws IOException {
124        if (procEnvironment == null) {
125            procEnvironment = this.createProcEnvironment();
126        }
127        // create a copy of the map just in case that
128        // anyone is going to modifiy it, e.g. removing
129        // or setting an evironment variable
130        final Map<String, String> copy = createEnvironmentMap();
131        copy.putAll(procEnvironment);
132        return copy;
133    }
134
135    /**
136     * Runs a process to list the environment variables.
137     *
138     * @return a reader containing the output of the process.
139     * @throws IOException starting the process failed.
140     * @deprecated No longer needed.
141     */
142    @Deprecated
143    protected BufferedReader runProcEnvCommand() throws IOException {
144//        final ByteArrayOutputStream out = new ByteArrayOutputStream();
145//        final Executor exe = DefaultExecutor.builder().get();
146//        exe.setStreamHandler(new PumpStreamHandler(out));
147//        // ignore the exit value - Just try to use what we got
148//        exe.execute(getProcEnvCommand());
149//        return new BufferedReader(new StringReader(toString(out)));
150        return null;
151    }
152
153}