TTYSessionInfo.java

   1 /*
   2  * Jexer - Java Text User Interface
   3  *
   4  * The MIT License (MIT)
   5  *
   6  * Copyright (C) 2017 Kevin Lamonte
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the "Software"),
  10  * to deal in the Software without restriction, including without limitation
  11  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  12  * and/or sell copies of the Software, and to permit persons to whom the
  13  * Software is furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  24  * DEALINGS IN THE SOFTWARE.
  25  *
  26  * @author Kevin Lamonte [kevin.lamonte@gmail.com]
  27  * @version 1
  28  */
  29 package jexer.backend;
  30
  31 import java.io.BufferedReader;
  32 import java.io.InputStreamReader;
  33 import java.io.IOException;
  34 import java.util.Date;
  35 import java.util.StringTokenizer;
  36
  37 /**
  38  * TTYSessionInfo queries environment variables and the tty window size for
  39  * the session information.  The username is taken from user.name, language
  40  * is taken from user.language, and text window size from 'stty size'.
  41  */
  42 public final class TTYSessionInfo implements SessionInfo {
  43
  44     /**
  45      * User name.
  46      */
  47     private String username = "";
  48
  49     /**
  50      * Language.
  51      */
  52     private String language = "";
  53
  54     /**
  55      * Text window width.  Default is 80x24 (same as VT100-ish terminals).
  56      */
  57     private int windowWidth = 80;
  58
  59     /**
  60      * Text window height.  Default is 80x24 (same as VT100-ish terminals).
  61      */
  62     private int windowHeight = 24;
  63
  64     /**
  65      * Time at which the window size was refreshed.
  66      */
  67     private Date lastQueryWindowTime;
  68
  69     /**
  70      * Username getter.
  71      *
  72      * @return the username
  73      */
  74     public String getUsername() {
  75         return this.username;
  76     }
  77
  78     /**
  79      * Username setter.
  80      *
  81      * @param username the value
  82      */
  83     public void setUsername(final String username) {
  84         this.username = username;
  85     }
  86
  87     /**
  88      * Language getter.
  89      *
  90      * @return the language
  91      */
  92     public String getLanguage() {
  93         return this.language;
  94     }
  95
  96     /**
  97      * Language setter.
  98      *
  99      * @param language the value
 100      */
 101     public void setLanguage(final String language) {
 102         this.language = language;
 103     }
 104
 105     /**
 106      * Call 'stty size' to obtain the tty window size.  windowWidth and
 107      * windowHeight are set automatically.
 108      */
 109     private void sttyWindowSize() {
 110         String [] cmd = {
 111             "/bin/sh", "-c", "stty size < /dev/tty"
 112         };
 113         try {
 114             Process process = Runtime.getRuntime().exec(cmd);
 115             BufferedReader in = new BufferedReader(
 116                 new InputStreamReader(process.getInputStream(), "UTF-8"));
 117             String line = in.readLine();
 118             if ((line != null) && (line.length() > 0)) {
 119                 StringTokenizer tokenizer = new StringTokenizer(line);
 120                 int rc = Integer.parseInt(tokenizer.nextToken());
 121                 if (rc > 0) {
 122                     windowHeight = rc;
 123                 }
 124                 rc = Integer.parseInt(tokenizer.nextToken());
 125                 if (rc > 0) {
 126                     windowWidth = rc;
 127                 }
 128             }
 129             while (true) {
 130                 BufferedReader err = new BufferedReader(
 131                         new InputStreamReader(process.getErrorStream(),
 132                             "UTF-8"));
 133                 line = err.readLine();
 134                 if ((line != null) && (line.length() > 0)) {
 135                     System.err.println("Error output from stty: " + line);
 136                 }
 137                 try {
 138                     process.waitFor();
 139                     break;
 140                 } catch (InterruptedException e) {
 141                     e.printStackTrace();
 142                 }
 143             }
 144             int rc = process.exitValue();
 145             if (rc != 0) {
 146                 System.err.println("stty returned error code: " + rc);
 147             }
 148         } catch (IOException e) {
 149             e.printStackTrace();
 150         }
 151     }
 152
 153     /**
 154      * Text window width getter.
 155      *
 156      * @return the window width
 157      */
 158     public int getWindowWidth() {
 159         if (System.getProperty("os.name").startsWith("Windows")) {
 160             // Always use 80x25 for Windows (same as DOS)
 161             return 80;
 162         }
 163         return windowWidth;
 164     }
 165
 166     /**
 167      * Text window height getter.
 168      *
 169      * @return the window height
 170      */
 171     public int getWindowHeight() {
 172         if (System.getProperty("os.name").startsWith("Windows")) {
 173             // Always use 80x25 for Windows (same as DOS)
 174             return 25;
 175         }
 176         return windowHeight;
 177     }
 178
 179     /**
 180      * Re-query the text window size.
 181      */
 182     public void queryWindowSize() {
 183         if (lastQueryWindowTime == null) {
 184             lastQueryWindowTime = new Date();
 185         } else {
 186             Date now = new Date();
 187             if (now.getTime() - lastQueryWindowTime.getTime() < 3000) {
 188                 // Don't re-spawn stty, it's been too soon.
 189                 return;
 190             }
 191         }
 192         if (System.getProperty("os.name").startsWith("Linux")
 193             || System.getProperty("os.name").startsWith("Mac OS X")
 194             || System.getProperty("os.name").startsWith("SunOS")
 195             || System.getProperty("os.name").startsWith("FreeBSD")
 196         ) {
 197             // Use stty to get the window size
 198             sttyWindowSize();
 199         }
 200     }
 201
 202     /**
 203      * Public constructor.
 204      */
 205     public TTYSessionInfo() {
 206         // Populate lang and user from the environment
 207         username = System.getProperty("user.name");
 208         language = System.getProperty("user.language");
 209         queryWindowSize();
 210     }
 211 }