Allow setting break-on-exceptions option over the service protocol.

runtime/observatory/lib/src/elements/debugger.dart

 // Copyright (c) 2014, 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.
 
 library debugger_page_element;
 
 import 'dart:async';
 import 'dart:html';
 import 'observatory_element.dart';
 import 'package:observatory/app.dart';
@@ skipping 348 matching lines @@
 
   String helpShort =
       'Continue running the isolate until the current function exits';
 
   String helpLong =
       'Continue running the isolate until the current function exits.\n'
       '\n'
       'Syntax: finish\n';
 }
 
+class SetCommand extends DebuggerCommand {
+  SetCommand(Debugger debugger)
+      : super(debugger, 'set', []);
+
+  Future run(List<String> args) async {
+    if (args.length == 2) {
+      var option = args[0].trim();
+      if (option == 'break-on-exceptions') {
+        var result = await debugger.isolate.setExceptionPauseInfo(args[1]);
+        if (result.isError) {
+          debugger.console.print(result.toString());
+        }
+      } else {
+        debugger.console.print("unknown option '$option'");
+      }
+    } else {
+      debugger.console.print("set expects 2 arguments");
+    }
+  }
+
+  String helpShort =
+      'Set a debugger option';
+
+  String helpLong =
+      'Set a debugger option'
+      '\n'
+      'Syntax: set break-on-exceptions "all" | "none" | "unhandled"\n';
+}
+
 class BreakCommand extends DebuggerCommand {
   BreakCommand(Debugger debugger) : super(debugger, 'break', []);
 
   Future run(List<String> args) async {
     if (args.length > 1) {
       debugger.console.print('not implemented');
       return new Future.value(null);
     }
     var arg = (args.length == 0 ? '' : args[0]);
     var loc = await DebuggerLocation.parse(debugger, arg);
@@ skipping 442 matching lines @@
       'Syntax: refresh <subcommand>\n';
 }
 
 // Tracks the state for an isolate debugging session.
 class ObservatoryDebugger extends Debugger {
   RootCommand cmd;
   DebuggerPageElement page;
   DebuggerConsoleElement console;
   DebuggerStackElement stackElement;
   ServiceMap stack;
+  String exceptions = "none";  // Last known setting.
 
   int get currentFrame => _currentFrame;
   void set currentFrame(int value) {
     if (value != null && (value < 0 || value >= stackDepth)) {
       throw new RangeError.range(value, 0, stackDepth);
     }
     _currentFrame = value;
     if (stackElement != null) {
       stackElement.setCurrentFrame(value);
     }
   }
   int _currentFrame = null;
 
   int get stackDepth => stack['frames'].length;
 
   ObservatoryDebugger() {
     cmd = new RootCommand([
         new HelpCommand(this),
         new PrintCommand(this),
         new DownCommand(this),
         new UpCommand(this),
         new FrameCommand(this),
         new PauseCommand(this),
         new ContinueCommand(this),
         new NextCommand(this),
         new StepCommand(this),
         new FinishCommand(this),
         new BreakCommand(this),
+        new SetCommand(this),
         new ClearCommand(this),
         new DeleteCommand(this),
         new InfoCommand(this),
         new IsolateCommand(this),
         new RefreshCommand(this),
     ]);
   }
 
   VM get vm => page.app.vm;
 
   void updateIsolate(Isolate iso) {
     _isolate = iso;
     if (_isolate != null) {
+      if (exceptions != iso.exceptionsPauseInfo) {
+        exceptions = iso.exceptionsPauseInfo;
+        console.print("Now pausing for $exceptions exceptions");
+      }
+
       _isolate.reload().then((response) {
         // TODO(turnidge): Currently the debugger relies on all libs
         // being loaded.  Fix this.
         var pending = [];
         for (var lib in _isolate.libraries) {
           if (!lib.loaded) {
             pending.add(lib.load());
           }
         }
         Future.wait(pending).then((_) {
@@ skipping 103 matching lines @@
       Frame frame = stack['frames'][0];
       var script = frame.location.script;
       script.load().then((_) {
         var line = script.tokenToLine(frame.location.tokenPos);
         var col = script.tokenToCol(frame.location.tokenPos);
         if (event.breakpoint != null) {
           var bpId = event.breakpoint.number;
           console.print('Paused at breakpoint ${bpId} at '
                         '${script.name}:${line}:${col}');
         } else if (event.exception != null) {
-          // TODO(turnidge): Test this.
-          console.print('Paused due to exception ${event.exception} at '
+          console.print('Paused due to exception at '
                         '${script.name}:${line}:${col}');
+          // This seems to be missing if we are paused-at-exception after
+          // paused-at-isolate-exit. Maybe we shutdown part of the debugger too
+          // soon?
+          console.printRef(event.exception);
         } else {
           console.print('Paused at ${script.name}:${line}:${col}');
         }
       });
     }
   }
 
   Future _reportBreakpointEvent(ServiceEvent event) {
     var bpt = event.breakpoint;
     var verb = null;
@@ skipping 41 matching lines @@
           var iso = event.owner;
           if (iso == isolate) {
             console.print("The current isolate has exited");
           } else {
             console.print(
                 "Isolate ${iso.number} '${iso.name}' has exited");
           }
         }
         break;
 
+      case ServiceEvent.kDebuggerSettingsUpdate:
+        if (exceptions != event.exceptions) {
+          exceptions = event.exceptions;
+          console.print("Now pausing for $exceptions exceptions");
+        }
+        break;
+
       case ServiceEvent.kIsolateUpdate:
         var iso = event.owner;
         console.print("Isolate ${iso.number} renamed to '${iso.name}'");
         break;
 
       case ServiceEvent.kPauseStart:
       case ServiceEvent.kPauseExit:
       case ServiceEvent.kPauseBreakpoint:
       case ServiceEvent.kPauseInterrupted:
       case ServiceEvent.kPauseException:
@@ skipping 594 matching lines @@
           default:
             busy = false;
             break;
         }
       });
   }
 
   DebuggerInputElement.created() : super.created();
 }