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
  42  * getpwuid(geteuid()).pw_name, language is taken from LANG, and text window
  43  * size from ioctl(TIOCGWINSIZ).
  44  */
  45 public final class TTYSessionInfo implements SessionInfo {
  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 Date lastQueryWindowTime;
  71
  72     /**
  73      * Username getter.
  74      *
  75      * @return the username
  76      */
  77     public String getUsername() {
  78         return this.username;
  79     }
  80
  81     /**
  82      * Username setter.
  83      *
  84      * @param username the value
  85      */
  86     public void setUsername(final String username) {
  87         this.username = username;
  88     }
  89
  90     /**
  91      * Language getter.
  92      *
  93      * @return the language
  94      */
  95     public String getLanguage() {
  96         return this.language;
  97     }
  98
  99     /**
 100      * Language setter.
 101      *
 102      * @param language the value
 103      */
 104     public void setLanguage(final String language) {
 105         this.language = language;
 106     }
 107
 108     /**
 109      * Call 'stty size' to obtain the tty window size.  windowWidth and
 110      * windowHeight are set automatically.
 111      */
 112     private void sttyWindowSize() {
 113         String [] cmd = {
 114             "/bin/sh", "-c", "stty size < /dev/tty"
 115         };
 116         try {
 117             Process process = Runtime.getRuntime().exec(cmd);
 118             BufferedReader in = new BufferedReader(
 119                 new InputStreamReader(process.getInputStream(), "UTF-8"));
 120             String line = in.readLine();
 121             if ((line != null) && (line.length() > 0)) {
 122                 StringTokenizer tokenizer = new StringTokenizer(line);
 123                 int rc = Integer.parseInt(tokenizer.nextToken());
 124                 if (rc > 0) {
 125                     windowHeight = rc;
 126                 }
 127                 rc = Integer.parseInt(tokenizer.nextToken());
 128                 if (rc > 0) {
 129                     windowWidth = rc;
 130                 }
 131             }
 132             while (true) {
 133                 BufferedReader err = new BufferedReader(
 134                         new InputStreamReader(process.getErrorStream(),
 135                             "UTF-8"));
 136                 line = err.readLine();
 137                 if ((line != null) && (line.length() > 0)) {
 138                     System.err.println("Error output from stty: " + line);
 139                 }
 140                 try {
 141                     process.waitFor();
 142                     break;
 143                 } catch (InterruptedException e) {
 144                     e.printStackTrace();
 145                 }
 146             }
 147             int rc = process.exitValue();
 148             if (rc != 0) {
 149                 System.err.println("stty returned error code: " + rc);
 150             }
 151         } catch (IOException e) {
 152             e.printStackTrace();
 153         }
 154     }
 155
 156     /**
 157      * Text window width getter.
 158      *
 159      * @return the window width
 160      */
 161     public int getWindowWidth() {
 162         if (System.getProperty("os.name").startsWith("Windows")) {
 163             // Always use 80x25 for Windows (same as DOS)
 164             return 80;
 165         }
 166         return windowWidth;
 167     }
 168
 169     /**
 170      * Text window height getter.
 171      *
 172      * @return the window height
 173      */
 174     public int getWindowHeight() {
 175         if (System.getProperty("os.name").startsWith("Windows")) {
 176             // Always use 80x25 for Windows (same as DOS)
 177             return 25;
 178         }
 179         return windowHeight;
 180     }
 181
 182     /**
 183      * Re-query the text window size.
 184      */
 185     public void queryWindowSize() {
 186         if (lastQueryWindowTime == null) {
 187             lastQueryWindowTime = new Date();
 188         } else {
 189             Date now = new Date();
 190             if (now.getTime() - lastQueryWindowTime.getTime() < 3000) {
 191                 // Don't re-spawn stty, it's been too soon.
 192                 return;
 193             }
 194         }
 195         if (System.getProperty("os.name").startsWith("Linux")
 196             || System.getProperty("os.name").startsWith("Mac OS X")
 197             || System.getProperty("os.name").startsWith("SunOS")
 198             || System.getProperty("os.name").startsWith("FreeBSD")
 199         ) {
 200             // Use stty to get the window size
 201             sttyWindowSize();
 202         }
 203     }
 204
 205     /**
 206      * Public constructor.
 207      */
 208     public TTYSessionInfo() {
 209         // Populate lang and user from the environment
 210         username = System.getProperty("user.name");
 211         language = System.getProperty("user.language");
 212         queryWindowSize();
 213     }
 214 }