src/jexer/session/TTYSessionInfo.java

   1 /*
   2  * Jexer - Java Text User Interface
   3  *
   4  * License: LGPLv3 or later
   5  *
   6  * This module is licensed under the GNU Lesser General Public License
   7  * Version 3.  Please see the file "COPYING" in this directory for more
   8  * information about the GNU Lesser General Public License Version 3.
   9  *
  10  *     Copyright (C) 2015  Kevin Lamonte
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU Lesser General Public License
  14  * as published by the Free Software Foundation; either version 3 of
  15  * the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Lesser General Public
  23  * License along with this program; if not, see
  24  * http://www.gnu.org/licenses/, or write to the Free Software
  25  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  26  * 02110-1301 USA
  27  *
  28  * @author Kevin Lamonte [kevin.lamonte@gmail.com]
  29  * @version 1
  30  */
  31 package jexer.session;
  32
  33 import java.io.BufferedReader;
  34 import java.io.InputStreamReader;
  35 import java.io.IOException;
  36 import java.util.Date;
  37 import java.util.StringTokenizer;
  38
  39 /**
  40  * TTYSessionInfo queries environment variables and the tty window size for
  41  * the session information.  The username is taken from user.name, language
  42  * is taken from user.language, and text window size from 'stty size'.
  43  */
  44 public final class TTYSessionInfo implements SessionInfo {
  45
  46     /**
  47      * User name.
  48      */
  49     private String username = "";
  50
  51     /**
  52      * Language.
  53      */
  54     private String language = "";
  55
  56     /**
  57      * Text window width.  Default is 80x24 (same as VT100-ish terminals).
  58      */
  59     private int windowWidth = 80;
  60
  61     /**
  62      * Text window height.  Default is 80x24 (same as VT100-ish terminals).
  63      */
  64     private int windowHeight = 24;
  65
  66     /**
  67      * Time at which the window size was refreshed.
  68      */
  69     private Date lastQueryWindowTime;
  70
  71     /**
  72      * Username getter.
  73      *
  74      * @return the username
  75      */
  76     public String getUsername() {
  77         return this.username;
  78     }
  79
  80     /**
  81      * Username setter.
  82      *
  83      * @param username the value
  84      */
  85     public void setUsername(final String username) {
  86         this.username = username;
  87     }
  88
  89     /**
  90      * Language getter.
  91      *
  92      * @return the language
  93      */
  94     public String getLanguage() {
  95         return this.language;
  96     }
  97
  98     /**
  99      * Language setter.
 100      *
 101      * @param language the value
 102      */
 103     public void setLanguage(final String language) {
 104         this.language = language;
 105     }
 106
 107     /**
 108      * Call 'stty size' to obtain the tty window size.  windowWidth and
 109      * windowHeight are set automatically.
 110      */
 111     private void sttyWindowSize() {
 112         String [] cmd = {
 113             "/bin/sh", "-c", "stty size < /dev/tty"
 114         };
 115         try {
 116             Process process = Runtime.getRuntime().exec(cmd);
 117             BufferedReader in = new BufferedReader(
 118                 new InputStreamReader(process.getInputStream(), "UTF-8"));
 119             String line = in.readLine();
 120             if ((line != null) && (line.length() > 0)) {
 121                 StringTokenizer tokenizer = new StringTokenizer(line);
 122                 int rc = Integer.parseInt(tokenizer.nextToken());
 123                 if (rc > 0) {
 124                     windowHeight = rc;
 125                 }
 126                 rc = Integer.parseInt(tokenizer.nextToken());
 127                 if (rc > 0) {
 128                     windowWidth = rc;
 129                 }
 130             }
 131             while (true) {
 132                 BufferedReader err = new BufferedReader(
 133                         new InputStreamReader(process.getErrorStream(),
 134                             "UTF-8"));
 135                 line = err.readLine();
 136                 if ((line != null) && (line.length() > 0)) {
 137                     System.err.println("Error output from stty: " + line);
 138                 }
 139                 try {
 140                     process.waitFor();
 141                     break;
 142                 } catch (InterruptedException e) {
 143                     e.printStackTrace();
 144                 }
 145             }
 146             int rc = process.exitValue();
 147             if (rc != 0) {
 148                 System.err.println("stty returned error code: " + rc);
 149             }
 150         } catch (IOException e) {
 151             e.printStackTrace();
 152         }
 153     }
 154
 155     /**
 156      * Text window width getter.
 157      *
 158      * @return the window width
 159      */
 160     public int getWindowWidth() {
 161         if (System.getProperty("os.name").startsWith("Windows")) {
 162             // Always use 80x25 for Windows (same as DOS)
 163             return 80;
 164         }
 165         return windowWidth;
 166     }
 167
 168     /**
 169      * Text window height getter.
 170      *
 171      * @return the window height
 172      */
 173     public int getWindowHeight() {
 174         if (System.getProperty("os.name").startsWith("Windows")) {
 175             // Always use 80x25 for Windows (same as DOS)
 176             return 25;
 177         }
 178         return windowHeight;
 179     }
 180
 181     /**
 182      * Re-query the text window size.
 183      */
 184     public void queryWindowSize() {
 185         if (lastQueryWindowTime == null) {
 186             lastQueryWindowTime = new Date();
 187         } else {
 188             Date now = new Date();
 189             if (now.getTime() - lastQueryWindowTime.getTime() < 3000) {
 190                 // Don't re-spawn stty, it's been too soon.
 191                 return;
 192             }
 193         }
 194         if (System.getProperty("os.name").startsWith("Linux")
 195             || System.getProperty("os.name").startsWith("Mac OS X")
 196             || System.getProperty("os.name").startsWith("SunOS")
 197             || System.getProperty("os.name").startsWith("FreeBSD")
 198         ) {
 199             // Use stty to get the window size
 200             sttyWindowSize();
 201         }
 202     }
 203
 204     /**
 205      * Public constructor.
 206      */
 207     public TTYSessionInfo() {
 208         // Populate lang and user from the environment
 209         username = System.getProperty("user.name");
 210         language = System.getProperty("user.language");
 211         queryWindowSize();
 212     }
 213 }