Implement generator mirror

src/mirror-debugger.js

Index: src/mirror-debugger.js
diff --git a/src/mirror-debugger.js b/src/mirror-debugger.js
index b13b3fa8b2457f28ab0e0c7be00ff5547f943ac3..0cfe318997d572921964717d1c20fab81c8f98a5 100644
--- a/src/mirror-debugger.js
+++ b/src/mirror-debugger.js
@@ -87,6 +87,8 @@ function MakeMirror(value, opt_transient) {
     mirror = new SetMirror(value);
   } else if (ObjectIsPromise(value)) {
     mirror = new PromiseMirror(value);
+  } else if (IS_GENERATOR(value)) {
+    mirror = new GeneratorMirror(value);
   } else {
     mirror = new ObjectMirror(value, OBJECT_TYPE, opt_transient);
   }
@@ -161,6 +163,7 @@ var SCOPE_TYPE = 'scope';
 var PROMISE_TYPE = 'promise';
 var MAP_TYPE = 'map';
 var SET_TYPE = 'set';
+var GENERATOR_TYPE = 'generator';
 
 // Maximum length when sending strings through the JSON protocol.
 var kMaxProtocolStringLength = 80;
@@ -214,6 +217,7 @@ var ScopeType = { Global: 0,
 //         - PromiseMirror
 //         - MapMirror
 //         - SetMirror
+//         - GeneratorMirror
 //     - PropertyMirror
 //     - InternalPropertyMirror
 //     - FrameMirror
@@ -371,6 +375,15 @@ Mirror.prototype.isPromise = function() {
 
 
 /**
+ * Check whether the mirror reflects a generator object.
+ * @returns {boolean} True if the mirror reflects a generator object
+ */
+Mirror.prototype.isGenerator = function() {
+  return this instanceof GeneratorMirror;
+};
+
+
+/**
  * Check whether the mirror reflects a property.
  * @returns {boolean} True if the mirror reflects a property
  */
@@ -986,8 +999,8 @@ FunctionMirror.prototype.script = function() {
  * @return {Number or undefined} in-script position for the function
  */
 FunctionMirror.prototype.sourcePosition_ = function() {
-  // Return script if function is resolved. Otherwise just fall through
-  // to return undefined.
+  // Return position if function is resolved. Otherwise just fall
+  // through to return undefined.
   if (this.resolved()) {
     return %FunctionGetScriptSourcePosition(this.value_);
   }
@@ -1352,6 +1365,66 @@ SetMirror.prototype.values = function() {
 
 
 /**
+ * Mirror object for a Generator object.
+ * @param {Object} data The Generator object
+ * @constructor
+ * @extends Mirror
+ */
+function GeneratorMirror(value) {
+  %_CallFunction(this, value, GENERATOR_TYPE, ObjectMirror);
+}
+inherits(GeneratorMirror, ObjectMirror);
+
+
+GeneratorMirror.prototype.status = function() {
+  var continuation = %GeneratorGetContinuation(this.value_);
+  if (continuation < 0) return "running";

[aandrey, 2014/09/17 13:21:29]

is it possible to test this status?

[wingo, 2014/09/17 13:54:30]

Done.

+  if (continuation == 0) return "closed";
+  return "suspended";
+};
+
+
+GeneratorMirror.prototype.sourcePosition_ = function() {
+  return %GeneratorGetSourcePosition(this.value_);
+};
+
+
+GeneratorMirror.prototype.sourceLocation = function() {
+  var pos = this.sourcePosition_();
+  if (!IS_UNDEFINED(pos)) {
+    var script = this.func().script();
+    if (script) {
+      return script.locationFromPosition(pos, true);
+    }
+  }
+};
+
+
+GeneratorMirror.prototype.func = function() {
+  if (!this.func_) {
+    this.func_ = MakeMirror(%GeneratorGetFunction(this.value_));
+  }
+  return this.func_;
+};
+
+
+GeneratorMirror.prototype.context = function() {

[aandrey, 2014/09/17 13:21:30]

Is this the same as this.func().script().context() ?

[wingo, 2014/09/17 13:54:30]

Hum, I realized that it isn't -- it's one of the other 30 things in V8 that are
named "context" :/

This thing is the scope chain.  In generator functions, all locals are reified
on the scope chain ("context-allocated").  You can get the set of local
variables from a generator activation by looking at the set of properties of a
node on the scope chain, stopping when you find a node that is on the scope
chain of the function itself.  However I revised the patch not to expose this
any more, as I don't know the right way to expose a scope chain.

+  if (!this.context_) {
+    this.context_ = new ContextMirror(%GeneratorGetContext(this.value_));
+  }
+  return this.context_;
+};
+
+
+GeneratorMirror.prototype.receiver = function() {
+  if (!this.receiver_) {
+    this.receiver_ = MakeMirror(%GeneratorGetReceiver(this.value_));
+  }
+  return this.receiver_;
+};
+
+
+/**
  * Base mirror object for properties.
  * @param {ObjectMirror} mirror The mirror object having this property
  * @param {string} name The name of the property
@@ -2539,6 +2612,7 @@ JSONProtocolSerializer.prototype.serialize_ = function(mirror, reference,
     case ERROR_TYPE:
     case REGEXP_TYPE:
     case PROMISE_TYPE:
+    case GENERATOR_TYPE:
       // Add object representation.
       this.serializeObject_(mirror, content, details);
       break;