Debugger wire protocol cleanups

tools/ddbg.dart

 // Copyright (c) 2012, 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.
 
 // Simple interactive debugger shell that connects to the Dart VM's debugger
 // connection port.
 
 import "dart:io";
 import "dart:json" as json;
 import "dart:utf";
 import "dart:async";
 
 
 Map<int, Completer> outstandingCommands;
 
 Socket vmSock;
 String vmData;
 var stdinSubscription;
 var vmSubscription;
 int seqNum = 0;
 int isolate_id = -1;
 
 final verbose = false;
 final printMessages = false;
 
-// The current stack trace, while the VM is paused. It's a list
-// of activation frames.
-List stackTrace;
-
-// The current activation frame, while the VM is paused.
-Map curFrame;
+// The location of the last paused event.
+Map pausedLocation = null;
 
 
 void printHelp() {
   print("""
   q   Quit debugger shell
   bt  Show backtrace
   r   Resume execution
   s   Single step
   so  Step over
   si  Step into
@@ skipping 42 matching lines @@
     return;
   }
   var command = args[0];
   var simple_commands =
       { 'r':'resume', 's':'stepOver', 'si':'stepInto', 'so':'stepOut'};
   if (simple_commands[command] != null) {
     var cmd = { "id": seqNum,
                 "command": simple_commands[command],
                 "params": { "isolateId" : isolate_id } };
     sendCmd(cmd).then((result) => handleGenericResponse(result));
-    stackTrace = curFrame = null;
   } else if (command == "bt") {
     var cmd = { "id": seqNum,
                 "command": "getStackTrace",
                 "params": { "isolateId" : isolate_id } };
     sendCmd(cmd).then((result) => handleStackTraceResponse(result));
   } else if (command == "ll") {
     var cmd = { "id": seqNum,
                 "command": "getLibraries",
                 "params": { "isolateId" : isolate_id } };
     sendCmd(cmd).then((result) => handleGetLibraryResponse(result));
   } else if (command == "sbp" && args.length >= 2) {
     var url, line;
-    if (args.length == 2) {
-      url = stackTrace[0]["location"]["url"];
+    if (args.length == 2 && pausedLocation != null) {
+      url = pausedLocation["url"];
+      assert(url != null);
       line = int.parse(args[1]);
     } else {
       url = args[1];
       line = int.parse(args[2]);
     }
     var cmd = { "id": seqNum,
                 "command": "setBreakpoint",
                 "params": { "isolateId" : isolate_id,
                             "url": url,
                             "line": line }};
@@ skipping 282 matching lines @@
 void printStackTrace(List frames) {
   for (int i = 0; i < frames.length; i++) {
     printStackFrame(i, frames[i]);
   }
 }
 
 
 void handlePausedEvent(msg) {
   assert(msg["params"] != null);
   var reason = msg["params"]["reason"];
-  isolate_id = msg["params"]["id"];
-  stackTrace = msg["params"]["callFrames"];
-  assert(stackTrace != null);
-  assert(stackTrace.length >= 1);
-  curFrame = stackTrace[0];
+  isolate_id = msg["params"]["isolateId"];
+  assert(isolate_id != null);
+  pausedLocation = msg["params"]["location"];
+  assert(pausedLocation != null);
   if (reason == "breakpoint") {
     print("Isolate $isolate_id paused on breakpoint");
+    print("location: $pausedLocation");
   } else if (reason == "interrupted") {
     print("Isolate $isolate_id paused due to an interrupt");
   } else {
     assert(reason == "exception");
     var excObj = msg["params"]["exception"];
     print("Isolate $isolate_id paused on exception");
     print(remoteObject(excObj));
   }
-  print("Stack trace:");
-  printStackTrace(stackTrace);
 }
 
 
 void processVmMessage(String jsonString) {
   var msg = json.parse(jsonString);
   if (msg == null) {
     return;
   }
   var event = msg["event"];
   if (event == "paused") {
@@ skipping 160 matching lines @@
       process.stdin.close();
       process.exitCode.then((int exitCode) {
         print('${arguments.join(" ")} exited with $exitCode');
       });
       debuggerMain();
     });
   } else {
     debuggerMain();
   }
 }