src/jexer/backend/TTYSessionInfo.java

   1 /*
   2  * Jexer - Java Text User Interface
   3  *
   4  * The MIT License (MIT)
   5  *
   6  * Copyright (C) 2019 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.StringTokenizer;
  35
  36 /**
  37  * TTYSessionInfo queries environment variables and the tty window size for
  38  * the session information.  The username is taken from user.name, language
  39  * is taken from user.language, and text window size from 'stty size'.
  40  */
  41 public class TTYSessionInfo implements SessionInfo {
  42
  43     // ------------------------------------------------------------------------
  44     // Variables --------------------------------------------------------------
  45     // ------------------------------------------------------------------------
  46
  47     /**
  48      * User name.
  49      */
  50     private String username = "";
  51
  52     /**
  53      * Language.
  54      */
  55     private String language = "";
  56
  57     /**
  58      * Text window width.  Default is 80x24 (same as VT100-ish terminals).
  59      */
  60     private int windowWidth = 80;
  61
  62     /**
  63      * Text window height.  Default is 80x24 (same as VT100-ish terminals).
  64      */
  65     private int windowHeight = 24;
  66
  67     /**
  68      * Time at which the window size was refreshed.
  69      */
  70     private long lastQueryWindowTime;
  71
  72     // ------------------------------------------------------------------------
  73     // Constructors -----------------------------------------------------------
  74     // ------------------------------------------------------------------------
  75
  76     /**
  77      * Public constructor.
  78      */
  79     public TTYSessionInfo() {
  80         // Populate lang and user from the environment
  81         username = System.getProperty("user.name");
  82         language = System.getProperty("user.language");
  83         queryWindowSize();
  84     }
  85
  86     // ------------------------------------------------------------------------
  87     // SessionInfo ------------------------------------------------------------
  88     // ------------------------------------------------------------------------
  89
  90     /**
  91      * Username getter.
  92      *
  93      * @return the username
  94      */
  95     public String getUsername() {
  96         return this.username;
  97     }
  98
  99     /**
 100      * Username setter.
 101      *
 102      * @param username the value
 103      */
 104     public void setUsername(final String username) {
 105         this.username = username;
 106     }
 107
 108     /**
 109      * Language getter.
 110      *
 111      * @return the language
 112      */
 113     public String getLanguage() {
 114         return this.language;
 115     }
 116
 117     /**
 118      * Language setter.
 119      *
 120      * @param language the value
 121      */
 122     public void setLanguage(final String language) {
 123         this.language = language;
 124     }
 125
 126     /**
 127      * Text window width getter.
 128      *
 129      * @return the window width
 130      */
 131     public int getWindowWidth() {
 132         if (System.getProperty("os.name").startsWith("Windows")) {
 133             // Always use 80x25 for Windows (same as DOS)
 134             return 80;
 135         }
 136         return windowWidth;
 137     }
 138
 139     /**
 140      * Text window height getter.
 141      *
 142      * @return the window height
 143      */
 144     public int getWindowHeight() {
 145         if (System.getProperty("os.name").startsWith("Windows")) {
 146             // Always use 80x25 for Windows (same as DOS)
 147             return 25;
 148         }
 149         return windowHeight;
 150     }
 151
 152     /**
 153      * Re-query the text window size.
 154      */
 155     public void queryWindowSize() {
 156         if (lastQueryWindowTime == 0) {
 157             lastQueryWindowTime = System.currentTimeMillis();
 158         } else {
 159             long nowTime = System.currentTimeMillis();
 160             if (nowTime - lastQueryWindowTime < 1000) {
 161                 // Don't re-spawn stty if it hasn't been a full second since
 162                 // the last time.
 163                 return;
 164             }
 165         }
 166         if (System.getProperty("os.name").startsWith("Linux")
 167             || System.getProperty("os.name").startsWith("Mac OS X")
 168             || System.getProperty("os.name").startsWith("SunOS")
 169             || System.getProperty("os.name").startsWith("FreeBSD")
 170         ) {
 171             // Use stty to get the window size
 172             sttyWindowSize();
 173         }
 174     }
 175
 176     // ------------------------------------------------------------------------
 177     // TTYSessionInfo ---------------------------------------------------------
 178     // ------------------------------------------------------------------------
 179
 180     /**
 181      * Call 'stty size' to obtain the tty window size.  windowWidth and
 182      * windowHeight are set automatically.
 183      */
 184     private void sttyWindowSize() {
 185         String [] cmd = {
 186             "/bin/sh", "-c", "stty size < /dev/tty"
 187         };
 188         try {
 189             Process process = Runtime.getRuntime().exec(cmd);
 190             BufferedReader in = new BufferedReader(
 191                 new InputStreamReader(process.getInputStream(), "UTF-8"));
 192             String line = in.readLine();
 193             if ((line != null) && (line.length() > 0)) {
 194                 StringTokenizer tokenizer = new StringTokenizer(line);
 195                 int rc = Integer.parseInt(tokenizer.nextToken());
 196                 if (rc > 0) {
 197                     windowHeight = rc;
 198                 }
 199                 rc = Integer.parseInt(tokenizer.nextToken());
 200                 if (rc > 0) {
 201                     windowWidth = rc;
 202                 }
 203             }
 204             while (true) {
 205                 BufferedReader err = new BufferedReader(
 206                         new InputStreamReader(process.getErrorStream(),
 207                             "UTF-8"));
 208                 line = err.readLine();
 209                 if ((line != null) && (line.length() > 0)) {
 210                     System.err.println("Error output from stty: " + line);
 211                 }
 212                 try {
 213                     process.waitFor();
 214                     break;
 215                 } catch (InterruptedException e) {
 216                     // SQUASH
 217                 }
 218             }
 219             int rc = process.exitValue();
 220             if (rc != 0) {
 221                 System.err.println("stty returned error code: " + rc);
 222             }
 223         } catch (IOException e) {
 224             e.printStackTrace();
 225         }
 226     }
 227
 228 }