Implement 'print', 'up', 'down', and 'frame' commands in the Observatory debugger.

runtime/vm/service.cc

 // 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.
 
 #include "vm/service.h"
 
 #include "include/dart_api.h"
 #include "platform/globals.h"
 
 #include "vm/compiler.h"
@@ skipping 1501 matching lines @@
     result.PrintJSON(js, true);
     return true;
   }
   PrintError(js, "%s: Invalid 'targetId' parameter value: "
              "id '%s' does not correspond to a "
              "library, class, or instance", js->method(), target_id);
   return true;
 }
 
 
+static const MethodParameter* eval_frame_params[] = {
+  ISOLATE_PARAMETER,
+  new UIntParameter("frame", true),
+  new MethodParameter("expression", true),
+  NULL,
+};
+
+
+static bool EvalFrame(Isolate* isolate, JSONStream* js) {
+  DebuggerStackTrace* stack = isolate->debugger()->StackTrace();
+  intptr_t framePos = UIntParameter::Parse(js->LookupParam("frame"));
+  if (framePos > stack->Length()) {
+    PrintInvalidParamError(js, "frame");
+    return true;
+  }
+  ActivationFrame* frame = stack->FrameAt(framePos);
+
+  const char* expr = js->LookupParam("expression");
+  const String& expr_str = String::Handle(isolate, String::New(expr));
+
+  const Object& result = Object::Handle(frame->Evaluate(expr_str));
+  result.PrintJSON(js, true);
+  return true;
+}
+
+
 static const MethodParameter* get_call_site_data_params[] = {
   ISOLATE_PARAMETER,
   new IdParameter("targetId", true),
   NULL,
 };
 
 
 static bool GetCallSiteData(Isolate* isolate, JSONStream* js) {
   const char* target_id = js->LookupParam("targetId");
   Object& obj = Object::Handle(LookupHeapObject(isolate, target_id, NULL));
@@ skipping 967 matching lines @@
   { "_triggerEchoEvent", _TriggerEchoEvent,
     NULL },
   { "addBreakpoint", AddBreakpoint,
     add_breakpoint_params },
   { "addBreakpointAtEntry", AddBreakpointAtEntry,
     add_breakpoint_at_entry_params },
   { "clearCpuProfile", ClearCpuProfile,
     clear_cpu_profile_params },
   { "eval", Eval,
     eval_params },
+  { "evalFrame", EvalFrame,
+    eval_frame_params },
   { "getAllocationProfile", GetAllocationProfile,
     get_allocation_profile_params },
   { "getCallSiteData", GetCallSiteData,
     get_call_site_data_params },
   { "getClassList", GetClassList,
     get_class_list_params },
   { "getCoverage", GetCoverage,
     get_coverage_params },
   { "getCpuProfile", GetCpuProfile,
     get_cpu_profile_params },
@@ skipping 51 matching lines @@
     ServiceMethodDescriptor& method = service_methods_[i];
     if (strcmp(method_name, method.name) == 0) {
       return &method;
     }
   }
   return NULL;
 }
 
 
 }  // namespace dart