Rework how we run/kill scripts and how we quit in ddbg.

tools/ddbg/lib/commando.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 import 'dart:math';
 
 import 'terminfo.dart';
@@ skipping 12 matching lines @@
   static const runeCtrlK   = 0x0b;
   static const runeCtrlL   = 0x0c;
   static const runeCtrlN   = 0x0e;
   static const runeCtrlP   = 0x10;
   static const runeCtrlU   = 0x15;
   static const runeCtrlY   = 0x19;
   static const runeESC     = 0x1b;
   static const runeSpace   = 0x20;
   static const runeDEL     = 0x7F;
 
-  Commando(this._stdin,
-           this._stdout,
-           this._handleCommand,
-           {this.prompt : '> ', this.completer : null}) {
+  StreamController<String> _commandController;
+
+  Stream get commands => _commandController.stream;
+
+  Commando({consoleIn,
+            consoleOut,
+            this.prompt : '> ',
+          this.completer : null}) {
+    _stdin = (consoleIn != null ? consoleIn : stdin);
+    _stdout = (consoleOut != null ? consoleOut : stdout);
+    _commandController = new StreamController<String>(
+        onCancel: _onCancel);
     _stdin.echoMode = false;
     _stdin.lineMode = false;
     _screenWidth = _term.cols - 1;
     _writePrompt();
+    // TODO(turnidge): Handle errors in _stdin here.
     _stdinSubscription =
-        _stdin.transform(UTF8.decoder).listen(_handleText, onDone:done);
+        _stdin.transform(UTF8.decoder).listen(_handleText, onDone:_done);
   }
 
+  Future _onCancel() {
+    _stdin.echoMode = true;
+    _stdin.lineMode = true;
+    var future = _stdinSubscription.cancel();
+    if (future != null) {
+      return future;
+    } else {
+      return new Future.value();
+    }
+  }
+
+  // Before terminating, call close() to restore terminal settings.
+  void _done() {
+    _onCancel().then((_) {
+        _commandController.close();
+      });
+  }
+  
   void _handleText(String text) {
     try {
       if (!_promptShown) {
         _bufferedInput.write(text);
         return;
       }
 
       var runes = text.runes.toList();
       var pos = 0;
       while (pos < runes.length) {
@@ skipping 17 matching lines @@
           _tabCount = 0;
         }
 
         if (_isControlRune(rune)) {
           pos += _handleControlSequence(runes, pos);
         } else {
           pos += _handleRegularSequence(runes, pos);
         }
       }
     } catch(e, trace) {
-      stderr.writeln('\nUnexpected exception: $e');
-      stderr.writeln(trace);
-      stderr.close().then((_) {
-          done();
-        });
+      _commandController.addError(e, trace);
     }
   }
 
   int _handleControlSequence(List<int> runes, int pos) {
     var runesConsumed = 1;  // Most common result.
     var char = runes[pos];
     switch (char) {
       case runeCtrlA:
         _home();
         break;
            
       case runeCtrlB:
         _leftArrow();
         break;
 
       case runeCtrlD:
         if (_currentLine.length == 0) {
           // ^D on an empty line means quit.
-          _stdout.writeln();
-          done();
+          _stdout.writeln("^D");
+          _done();
         } else {
           _delete();
         }
         break;
            
       case runeCtrlE:
         _end();
         break;
            
       case runeCtrlF:
@@ skipping 83 matching lines @@
       len++;
     }
     _addChars(runes.getRange(pos, len));
     return len;
   }
 
   bool _isControlRune(int char) {
     return (char >= 0x00 && char < 0x20) || (char == 0x7f);
   }
 
-  void done() {
-    _stdin.echoMode = true;
-    _stdin.lineMode = true;
-    _stdinSubscription.cancel();
-  }
-
   void _writePromptAndLine() {
     _writePrompt();
     var pos = _writeRange(_currentLine, 0, _currentLine.length);
     _cursorPos = _move(pos, _cursorPos);
   }
 
   void _writePrompt() {
     _stdout.write(prompt);
   }
 
@@ skipping 135 matching lines @@
   }
 
   void _newline() {
     _addLineToHistory(_currentLine);
     _linePos = _lines.length;
 
     _end();
     _stdout.writeln();
 
     // Call the user's command handler.
-    _handleCommand(new String.fromCharCodes(_currentLine));
+    _commandController.add(new String.fromCharCodes(_currentLine));
     
     _currentLine = [];
     _cursorPos = 0;
     _linePos = _lines.length;
     if (_promptShown) {
       _writePrompt();
     }
   }
 
   void _leftArrow() {
@@ skipping 221 matching lines @@
   }
 
   int _getCol(int pos) {
     var truePos = pos + prompt.length;
     return truePos % _screenWidth;
   }
 
   Stdin _stdin;
   StreamSubscription _stdinSubscription;
   IOSink _stdout;
-  final _handleCommand;
   final String prompt;
   bool _promptShown = true;
   final CommandCompleter completer;
   TermInfo _term = new TermInfo();
 
   // TODO(turnidge): Update screenwidth when we clear the screen.  See
   // if we can get screen resize events too.
   int _screenWidth;
   List<int> _currentLine = [];  // A list of runes.
   StringBuffer _bufferedInput = new StringBuffer();
@@ skipping 45 matching lines @@
   return completions;
 }
 
 
 int _helpCount = 0;
 Commando cmdo;
 
 
 void _handleCommand(String rawCommand) {
   String command = rawCommand.trim();
+  cmdo.hide();
   if (command == 'quit') {
-    cmdo.done();
+    cmdo.close().then((_) {
+        print('Exiting');
+      });
   } else if (command == 'help') {
     switch (_helpCount) {
       case 0:
         print('I will not help you.');
         break;
       case 1:
         print('I mean it.');
         break;
       case 2:
         print('Seriously.');
         break;
       case 100:
         print('Well now.');
         break;
       default:
         print("Okay.  Type 'quit' to quit");
         break;
     }
     _helpCount++;
   } else if (command == 'happyface') {
     print(':-)');
   } else {
     print('Received command($command)');
   }
+  cmdo.show();
 }
 
 
 void main() {
-  stdout.writeln('[Commando demo]');
-  cmd = new Commando(stdin, stdout, _handleCommand,
-                     completer:_myCompleter);
+  print('[Commando demo]');
+  cmdo = new Commando(completer:_myCompleter);
+  cmdo.commands.listen(_handleCommand);
 }