Issue 2081: Expose function's (closure's) inner context in debugger.

src/debug-debugger.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1939 matching lines @@
   response.body = this.exec_state_.frame();
 };
 
 
 DebugCommandProcessor.prototype.frameForScopeRequest_ = function(request) {
   // Get the frame for which the scope or scopes are requested.
   // With no frameNumber argument use the currently selected frame.
   if (request.arguments && !IS_UNDEFINED(request.arguments.frameNumber)) {
     frame_index = request.arguments.frameNumber;
     if (frame_index < 0 || this.exec_state_.frameCount() <= frame_index) {
+      // TODO: this doesn't work. We cannot simply return response from here,
+      // use exception instead.
       return response.failed('Invalid frame number');
     }
     return this.exec_state_.frame(frame_index);
   } else {
     return this.exec_state_.frame();
   }
 };
 
 
+// Gets scope host object from request. It is either a function
+// ('functionHandle' argument must be specified) or a stack frame
+// ('frameNumber' may be specified and the current frame is taken by default).
+DebugCommandProcessor.prototype.scopeHolderForScopeRequest_ =
+    function(request) {
+  if (request.arguments && "functionHandle" in request.arguments) {
+    if (!IS_NUMBER(request.arguments.functionHandle)) {
+      throw new Error('Function handle must be a number');
+    }
+    var function_mirror = LookupMirror(request.arguments.functionHandle);
+    if (!function_mirror) {
+      throw new Error('Failed to find function object by handle');
+    }
+    if (!function_mirror.isFunction()) {
+      throw new Error('Value of non-function type is found by handle');
+    }
+    return function_mirror;
+  } else {
+    // No frames no scopes.
+    if (this.exec_state_.frameCount() == 0) {
+      throw new Error('No scopes');
+    }
+        
+    // Get the frame for which the scopes are requested.
+    var frame = this.frameForScopeRequest_(request);
+    return frame;
+  }
+}
+
+
 DebugCommandProcessor.prototype.scopesRequest_ = function(request, response) {
-  // No frames no scopes.
-  if (this.exec_state_.frameCount() == 0) {
-    return response.failed('No scopes');
-  }
+  var scope_holder = this.scopeHolderForScopeRequest_(request);
 
-  // Get the frame for which the scopes are requested.
-  var frame = this.frameForScopeRequest_(request);
-
-  // Fill all scopes for this frame.
-  var total_scopes = frame.scopeCount();
+  // Fill all scopes for this frame or function.
+  var total_scopes = scope_holder.scopeCount();
   var scopes = [];
   for (var i = 0; i < total_scopes; i++) {
-    scopes.push(frame.scope(i));
+    scopes.push(scope_holder.scope(i));
   }
   response.body = {
     fromScope: 0,
     toScope: total_scopes,
     totalScopes: total_scopes,
     scopes: scopes
   };
 };
 
 
 DebugCommandProcessor.prototype.scopeRequest_ = function(request, response) {
-  // No frames no scopes.
-  if (this.exec_state_.frameCount() == 0) {
-    return response.failed('No scopes');
-  }
-
-  // Get the frame for which the scope is requested.
-  var frame = this.frameForScopeRequest_(request);
+  // Get the frame or function for which the scope is requested.
+  var scope_holder = this.scopeHolderForScopeRequest_(request);
 
   // With no scope argument just return top scope.
   var scope_index = 0;
   if (request.arguments && !IS_UNDEFINED(request.arguments.number)) {
     scope_index = %ToNumber(request.arguments.number);
-    if (scope_index < 0 || frame.scopeCount() <= scope_index) {
+    if (scope_index < 0 || scope_holder.scopeCount() <= scope_index) {
       return response.failed('Invalid scope number');
     }
   }
 
-  response.body = frame.scope(scope_index);
+  response.body = scope_holder.scope(scope_index);
 };
 
 
 DebugCommandProcessor.prototype.evaluateRequest_ = function(request, response) {
   if (!request.arguments) {
     return response.failed('Missing arguments');
   }
 
   // Pull out arguments.
   var expression = request.arguments.expression;
@@ skipping 585 matching lines @@
     case 'string':
     case 'number':
       json = value;
       break;
 
     default:
       json = null;
   }
   return json;
 }