src/jexer/backend/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.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 final class TTYSessionInfo implements SessionInfo {
  42
  43     /**
  44      * User name.
  45      */
  46     private String username = "";
  47
  48     /**
  49      * Language.
  50      */
  51     private String language = "";
  52
  53     /**
  54      * Text window width.  Default is 80x24 (same as VT100-ish terminals).
  55      */
  56     private int windowWidth = 80;
  57
  58     /**
  59      * Text window height.  Default is 80x24 (same as VT100-ish terminals).
  60      */
  61     private int windowHeight = 24;
  62
  63     /**
  64      * Time at which the window size was refreshed.
  65      */
  66     private long lastQueryWindowTime;
  67
  68     /**
  69      * Username getter.
  70      *
  71      * @return the username
  72      */
  73     public String getUsername() {
  74         return this.username;
  75     }
  76
  77     /**
  78      * Username setter.
  79      *
  80      * @param username the value
  81      */
  82     public void setUsername(final String username) {
  83         this.username = username;
  84     }
  85
  86     /**
  87      * Language getter.
  88      *
  89      * @return the language
  90      */
  91     public String getLanguage() {
  92         return this.language;
  93     }
  94
  95     /**
  96      * Language setter.
  97      *
  98      * @param language the value
  99      */
 100     public void setLanguage(final String language) {
 101         this.language = language;
 102     }
 103
 104     /**
 105      * Call 'stty size' to obtain the tty window size.  windowWidth and
 106      * windowHeight are set automatically.
 107      */
 108     private void sttyWindowSize() {
 109         String [] cmd = {
 110             "/bin/sh", "-c", "stty size < /dev/tty"
 111         };
 112         try {
 113             Process process = Runtime.getRuntime().exec(cmd);
 114             BufferedReader in = new BufferedReader(
 115                 new InputStreamReader(process.getInputStream(), "UTF-8"));
 116             String line = in.readLine();
 117             if ((line != null) && (line.length() > 0)) {
 118                 StringTokenizer tokenizer = new StringTokenizer(line);
 119                 int rc = Integer.parseInt(tokenizer.nextToken());
 120                 if (rc > 0) {
 121                     windowHeight = rc;
 122                 }
 123                 rc = Integer.parseInt(tokenizer.nextToken());
 124                 if (rc > 0) {
 125                     windowWidth = rc;
 126                 }
 127             }
 128             while (true) {
 129                 BufferedReader err = new BufferedReader(
 130                         new InputStreamReader(process.getErrorStream(),
 131                             "UTF-8"));
 132                 line = err.readLine();
 133                 if ((line != null) && (line.length() > 0)) {
 134                     System.err.println("Error output from stty: " + line);
 135                 }
 136                 try {
 137                     process.waitFor();
 138                     break;
 139                 } catch (InterruptedException e) {
 140                     e.printStackTrace();
 141                 }
 142             }
 143             int rc = process.exitValue();
 144             if (rc != 0) {
 145                 System.err.println("stty returned error code: " + rc);
 146             }
 147         } catch (IOException e) {
 148             e.printStackTrace();
 149         }
 150     }
 151
 152     /**
 153      * Text window width getter.
 154      *
 155      * @return the window width
 156      */
 157     public int getWindowWidth() {
 158         if (System.getProperty("os.name").startsWith("Windows")) {
 159             // Always use 80x25 for Windows (same as DOS)
 160             return 80;
 161         }
 162         return windowWidth;
 163     }
 164
 165     /**
 166      * Text window height getter.
 167      *
 168      * @return the window height
 169      */
 170     public int getWindowHeight() {
 171         if (System.getProperty("os.name").startsWith("Windows")) {
 172             // Always use 80x25 for Windows (same as DOS)
 173             return 25;
 174         }
 175         return windowHeight;
 176     }
 177
 178     /**
 179      * Re-query the text window size.
 180      */
 181     public void queryWindowSize() {
 182         if (lastQueryWindowTime == 0) {
 183             lastQueryWindowTime = System.currentTimeMillis();
 184         } else {
 185             long nowTime = System.currentTimeMillis();
 186             if (nowTime - lastQueryWindowTime < 1000) {
 187                 // Don't re-spawn stty if it hasn't been a full second since
 188                 // the last time.
 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 }