Support more debugger commands in the wire protocol

tools/ddbg.dart

Index: tools/ddbg.dart
===================================================================
--- tools/ddbg.dart	(revision 0)
+++ tools/ddbg.dart	(revision 0)
@@ -0,0 +1,195 @@
+// 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");
+
+Map<int, Completer> outstandingCommands;
+
+Socket vmSock;
+OutputStream vmStream;
+int seqNum = 0;
+
+bool verbose = false;
+
+
+void printHelp() {
+  print("""
+  q   Quit debugger shell
+  r   Resume execution
+  s   Single step
+  so  Step over
+  si  Step into
+  ll  List loaded libraries
+  ls <libname> List loaded scripts in library
+""");
+}
+
+
+void quitShell() {
+  vmStream.close();
+  vmSock.close();
+  stdin.close();
+}
+
+
+Future sendCmd(Map<String, Dynamic> cmd) {
+  var completer = new Completer();
+  assert(cmd["id"] != null);
+  var id = cmd["id"];
+  outstandingCommands[id] = completer;
+  if (verbose) {
+    print("sending: '${JSON.stringify(cmd)}'");
+  }
+  vmStream.writeString(JSON.stringify(cmd));
+  return completer.future;
+}
+
+
+void processCommand(String cmdLine) {
+  seqNum++;
+  var args = cmdLine.split(' ');
+  if (args.length == 0) {
+    return;
+  }
+  var cmd = args[0];
+  if (cmd == "r") {
+    var cmd = { "id": seqNum, "command": "resume" };
+    sendCmd(cmd).then((result) => handleGenericResponse(result));
+  } else if (cmd == "s") {
+    var cmd = { "id": seqNum, "command": "stepOver" };
+    sendCmd(cmd).then((result) => handleGenericResponse(result));
+  } else if (cmd == "si") {
+    var cmd = { "id": seqNum, "command": "stepInto" };
+    sendCmd(cmd).then((result) => handleGenericResponse(result));
+  } else if (cmd == "so") {
+    var cmd = { "id": seqNum, "command": "stepOut" };
+    sendCmd(cmd).then((result) => handleGenericResponse(result));
+  } else if (cmd == "ll") {
+    var cmd = { "id": seqNum, "command": "getLibraryURLs" };
+    sendCmd(cmd).then((result) => handleGetLibraryResponse(result));
+  } else if (cmd == "ls") {
+    if (args.length < 2) {
+      return;
+    }
+    var cmd = { "id": seqNum, "command": "getScriptURLs",
+                 "param": { "library": args[1] }};
+    sendCmd(cmd).then((result) => handleGetScriptsResponse(result));
+  } else if (cmd == "q") {
+    quitShell();
+  } else if (cmd == "h") {
+    printHelp();
+  } else {
+    print("Error: $cmd not understood");
+  }
+}
+
+
+void handleGetLibraryResponse(response) {
+  var result = response["result"];
+  assert(result != null);
+  var urls = result["urls"];
+  assert(urls != null);
+  assert(urls is List);
+  print("Loaded isolates:");
+  for (int i = 0; i < urls.length; i++) {
+    print("  $i ${urls[i]}");
+  }
+}
+
+
+void handleGetScriptsResponse(response) {
+  var result = response["result"];
+  assert(result != null);
+  var urls = result["urls"];
+  assert(urls != null);
+  assert(urls is List);
+  print("Loaded scripts:");
+  for (int i = 0; i < urls.length; i++) {
+    print("  $i ${urls[i]}");
+  }
+}
+
+
+void handleGenericResponse(response) {
+  if (response["error"] != null) {
+    print("Error: ${response["error"]}");
+  }
+}
+
+
+void printStackTrace(var trace) {
+  if (trace == null) {
+    return;
+  }
+  var frames = trace["callFrames"];
+  if (frames is !List) {
+    print("unexpected type for frames parameter $frames");
+    return;
+  }
+  for (int i = 0; i < frames.length; i++) {
+    var frame = frames[i];
+    var fname = frame["functionName"];
+    var url = frame["location"]["url"];
+    var line = frame["location"]["lineNumber"];
+    print("$i  $fname ($url:$line)");
+  }
+}
+
+
+// TODO(hausner): Need to handle the case where we receive only a partial
+// message from the debugger, e.g. when the message is too big to fit in
+// one network packet.
+void processVmData(String s) {
+  if (verbose) print("vm: $s");
+  var msg = JSON.parse(s);
+  if (msg == null) {
+    return;
+  }
+  var event = msg["event"];
+  if (event == "paused") {
+    print("VM paused, stack trace:");
+    printStackTrace(msg["params"]);
+    return;
+  }
+  if (msg["id"] != null) {
+    var id = msg["id"];
+    if (outstandingCommands.containsKey(id)) {
+      if (msg["error"] != null) {
+        print("VM says: ${msg["error"]}");
+      } else {
+        var completer = outstandingCommands[id];
+        completer.complete(msg);
+      }
+      outstandingCommands.remove(id);
+    }
+  }
+}
+
+
+void main() {
+  outstandingCommands = new Map<int, Completer>();
+  vmSock = new Socket("127.0.0.1", 5858);
+  vmStream = new SocketOutputStream(vmSock);
+  var stdinStream = new StringInputStream(stdin);
+  stdinStream.onLine = () {
+    processCommand(stdinStream.readLine());
+  };
+  var vmInStream = new SocketInputStream(vmSock);
+  vmInStream.onData = () {
+    var s = new String.fromCharCodes(vmInStream.read());
+    processVmData(s);
+  };
+  vmInStream.onError = (err) {
+    print("Error in debug connection: $err");
+    quitShell();
+  };
+  vmInStream.onClosed = () {
+    print("VM debugger connection closed");
+    quitShell();
+  };
+}