Add string encoding to wire protocol

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");
 
@@ skipping 21 matching lines @@
   s   Single step
   so  Step over
   si  Step into
   sbp [<file>] <line> Set breakpoint
   rbp <id> Remove breakpoint with given id
   po <id> Print object info for given id
   pc <id> Print class info for given id
   ll  List loaded libraries
   pl <id> Print dlibrary info for given id
   ls <libname> List loaded scripts in library
+  gs <lib_id> <script_url> Get source text of script in library
   h   Print help
 """);
 }
 
 
 void quitShell() {
   vmStream.close();
   vmSock.close();
   stdin.close();
 }
@@ skipping 58 matching lines @@
                 "params": {"objectId": Math.parseInt(args[1]) }};
     sendCmd(cmd).then((result) => handleGetObjPropsResponse(result));
   } else if (command == "pc" && args.length == 2) {
     var cmd = { "id": seqNum, "command": "getClassProperties",
                 "params": {"classId": Math.parseInt(args[1]) }};
     sendCmd(cmd).then((result) => handleGetClassPropsResponse(result));
   } else if (command == "pl" && args.length == 2) {
     var cmd = { "id": seqNum, "command": "getLibraryProperties",
                 "params": {"libraryId": Math.parseInt(args[1]) }};
     sendCmd(cmd).then((result) => handleGetLibraryPropsResponse(result));
+  } else if (command == "gs" && args.length == 3) {
+    var cmd = { "id": seqNum, "command":  "getScriptSource",
+                "params": { "libraryId": Math.parseInt(args[1]),
+                            "url": args[2] }};
+    sendCmd(cmd).then((result) => handleGetSourceResponse(result));
   } else if (command == "q") {
     quitShell();
   } else if (command == "h") {
     printHelp();
   } else {
     print("command '$command' not understood, try h for help");
   }
 }
 
 
@@ skipping 60 matching lines @@
   assert(globals != null);
   if (globals.length > 0) {
     print("  global variables:");
     for (int i = 0; i < globals.length; i++) {
       printNamedObject(globals[i]);
     }
   }
 }
 
 
+handleGetSourceResponse(response) {
+  Map result = response["result"];
+  String source = result["text"];
+  print("Source text:\n$source\n--------");
+}
+
+
 void handleGetLibraryResponse(response) {
   Map result = response["result"];
   List libs = result["libraries"];
   print("Loaded libraries:");
   print(libs);
   for (int i = 0; i < libs.length; i++) {
     print("  ${libs[i]["id"]} ${libs[i]["url"]}");
   }
 }
 
@@ skipping 136 matching lines @@
   };
   vmInStream.onError = (err) {
     print("Error in debug connection: $err");
     quitShell();
   };
   vmInStream.onClosed = () {
     print("VM debugger connection closed");
     quitShell();
   };
 }