Adding a tty check for stdin

ChangeLog

@@ -1,4 +1,5 @@
-2020-02-08  Markus Gans  <guru.mail@muenster.de>
+2020-02-09  Markus Gans  <guru.mail@muenster.de>
+	* Adding a tty check for stdin
 	* An application structure diagram was added to the document 
 	  of the first steps
 

doc/final-cut-application-structure.svg

@@ -12,7 +12,7 @@
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@@ -27,13 +27,13 @@
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@@ -42,7 +42,7 @@
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doc/first-steps.md

@@ -29,9 +29,22 @@ Table of Contents
 Basic functions
 ---------------
 
-FINAL CUT is a library for creating text-based terminal applications. It runs on several Unix-like platforms. The release of FINAL CUT is licensed under the terms of the GNU Lesser General Public License v3.0 ([GNU LGPL v3](https://www.gnu.org/licenses/lgpl-3.0-standalone.html)), which allows flexible licensing of applications. FINAL CUT has a [C++](https://en.wikipedia.org/wiki/C%2B%2B)-based object-oriented architecture for creating fast and lean programs.
+FINAL CUT is a library for creating text-based terminal applications.
+It runs on several Unix-like platforms. The release of FINAL CUT is
+licensed under the terms of the GNU Lesser General Public License v3.0
+([GNU LGPL v3](https://www.gnu.org/licenses/lgpl-3.0-standalone.html)),
+which allows flexible licensing of applications. FINAL CUT was written
+in the programming language [C++](https://en.wikipedia.org/wiki/C%2B%2B).
+The object-oriented design allows the creation of fast and lean programs.
 
-FINAL CUT is a [widget toolkit](http://en.wikipedia.org/wiki/Widget_toolkit). A user interface created consists of several widgets. FINAL CUT draws widgets on virtual windows and then mapped them on a virtual terminal. It uses the terminal capabilities from the [Termcap library](https://en.wikipedia.org/wiki/Termcap) to display the character matrix of the virtual terminal on the screen or a terminal emulator. It uses various optimization methods to improve the speed of the display.
+FINAL CUT is a [widget toolkit](http://en.wikipedia.org/wiki/Widget_toolkit).
+A user interface usually consists of several
+[widgets](https://en.wikipedia.org/wiki/Software_widget). FINAL CUT
+draws widgets on virtual windows and then mapped them on a virtual
+terminal. It uses the terminal capabilities from the
+[Termcap library](https://en.wikipedia.org/wiki/Termcap) to display
+the character matrix of the virtual terminal on the screen or a terminal
+emulator. It uses various optimization methods to improve the drawing speed.
 
 <figure class="image">
   <img src="final-cut-application-structure.svg" alt="application structure">

src/fterm.cpp

@@ -25,6 +25,7 @@
 #include <string>
 #include <vector>
 
+#include "final/fapplication.h"
 #include "final/fc.h"
 #include "final/fcharmap.h"
 #include "final/fcolorpalette.h"
@@ -2211,24 +2212,9 @@ void FTerm::init (bool disable_alt_screen)
   allocationValues();
   init_global_values(disable_alt_screen);
 
-  // Initialize termios
+  // Initialize the terminal
-  FTermios::init();
+  if ( ! init_terminal() )
-
+    return;
-  // Get pathname of the terminal device
-  init_terminal_device_path();
-
-  // Initialize Linux or *BSD console
-  initOSspecifics();
-
-  // Save termios settings
-  FTermios::storeTTYsettings();
-
-  // Get output baud rate
-  initBaudRate();
-
-  // Terminal detection
-  term_detection->detect();
-  setTermType (term_detection->getTermType());
 
   // Set maximum number of colors for detected terminals
   init_fixed_max_color();
@@ -2312,6 +2298,49 @@ void FTerm::init (bool disable_alt_screen)
   term_initialized = true;
 }
 
+//----------------------------------------------------------------------
+bool FTerm::init_terminal()
+{
+  // Initialize termios
+  FTermios::init();
+
+  // Check if stdin is a tty
+  if ( ! fsys->isTTY(FTermios::getStdIn()) )
+  {
+    data->setExitMessage("FTerm: Standard input is not a TTY.");
+    FApplication::exit(EXIT_FAILURE);
+    return false;
+  }
+
+  // Get pathname of the terminal device
+  init_terminal_device_path();
+
+  // Initialize Linux or *BSD console
+  initOSspecifics();
+
+  // Save termios settings
+  try
+  {
+    FTermios::storeTTYsettings();
+  }
+  catch (const std::runtime_error& ex)
+  {
+    FString msg = "FTerm: " + FString(ex.what());
+    data->setExitMessage(msg);
+    FApplication::exit(EXIT_FAILURE);
+    return false;
+  }
+
+  // Get output baud rate
+  initBaudRate();
+
+  // Terminal detection
+  term_detection->detect();
+  setTermType (term_detection->getTermType());
+
+  return true;
+}
+
 //----------------------------------------------------------------------
 void FTerm::initOSspecifics()
 {

src/ftermios.cpp

@@ -3,7 +3,7 @@
 *                                                                      *
 * This file is part of the Final Cut widget toolkit                    *
 *                                                                      *
-* Copyright 2018-2019 Markus Gans                                      *
+* Copyright 2018-2020 Markus Gans                                      *
 *                                                                      *
 * The Final Cut is free software; you can redistribute it and/or       *
 * modify it under the terms of the GNU Lesser General Public License   *
@@ -72,7 +72,10 @@ void FTermios::init()
 termios FTermios::getTTY()
 {
   struct termios t{};
-  tcgetattr (stdin_no, &t);
+
+  if ( tcgetattr(stdin_no, &t) == -1 )
+    std::runtime_error("Cannot find tty");
+
   return t;
 }
 
@@ -86,8 +89,15 @@ void FTermios::setTTY (const termios& t)
 void FTermios::storeTTYsettings()
 {
   // Store termios settings
+  try
+  {
     term_init = getTTY();
   }
+  catch (...)
+  {
+    throw std::current_exception();
+  }
+}
 
 //----------------------------------------------------------------------
 void FTermios::restoreTTYsettings()

src/include/final/fterm.h

@@ -343,6 +343,7 @@ class FTerm final
     void                   allocationValues();
     void                   deallocationValues();
     void                   init (bool);
+    bool                   init_terminal();
     void                   initOSspecifics();
     void                   initTermspecifics();
     void                   initBaudRate();