chakrashim: add dummy Debug.MakeMirror

Latest node util uses Debug.MakeMirror to inspect Promise objects. This
change adds a dummy Debug.MakeMirror implementation which always returns
```Promise { '<unknown>' }```, to avoid displaying an exception stack
when inspecting Promise objects.

PR-URL: #42
Reviewed-By: Sandeep Agarwal <[email protected]>
Reviewed-By: Kunal Pathak <[email protected]>

deps/chakrashim/lib/chakra_shim.js

@@ -307,6 +307,81 @@
     });
   }
 
+  // Ensure global Debug object if not already exists, and patch it.
+  function ensureDebug(otherGlobal) {
+    if (!global.Debug) {
+      Object_defineProperty(global, 'Debug', {
+        value: {}, enumerable : false, configurable : false, writable : false
+      });
+    }
+
+    otherProcess = otherGlobal.process;
+    patchDebug(global.Debug);
+  }
+
+  var otherProcess;
+
+  function patchDebug(Debug) {
+    if (!Debug || Debug.MakeMirror) {
+      return;
+    }
+
+    class Mirror {
+      constructor(type) {
+        this.type_ = type;
+      }
+      type() {
+        return this.type_;
+      }
+    }
+
+    class ValueMirror extends Mirror {
+      constructor(type, value) {
+        super(type);
+        this.value_ = value;
+      }
+      value() {
+        return this.value_;
+      }
+    }
+
+    class UndefinedMirror extends ValueMirror {
+      constructor() {
+        super('undefined', undefined);
+      }
+    }
+    const undefinedMirror = new UndefinedMirror();
+
+    class ObjectMirror extends ValueMirror {
+      constructor(type, value) {
+        super(type || 'object', value);
+      }
+    }
+
+    class PromiseMirror extends ObjectMirror {
+      constructor(value) {
+        super('promise', value);
+      }
+      status() {
+        return '<unknown>';
+      }
+      promiseValue() {
+        return new ValueMirror('<unknown>', '<unknown>');
+      }
+    }
+
+    const util = otherProcess.binding('util');
+
+    Debug.MakeMirror = (value) => {
+      if (util.isPromise(value)) {
+        return new PromiseMirror(value);
+      }
+
+      // Not supporting other types
+      return undefinedMirror;
+    };
+  }
+
   function patchUtils(utils) {
     var isUintRegex = /^(0|[1-9]\\d*)$/;
 
@@ -437,6 +512,7 @@
     utils.getSymbolFor = function(key) {
       return Symbol_for(key);
     };
+    utils.ensureDebug = ensureDebug;
   }
 
   patchErrorTypes();

deps/chakrashim/src/jsrtcachedpropertyidref.inc

@@ -69,6 +69,7 @@ DEF(getIndexedOwnKeys)
 DEF(getStackTrace)
 DEF(getSymbolKeyFor)
 DEF(getSymbolFor)
+DEF(ensureDebug)
 DEF(getFunctionName)
 DEF(getFileName)
 DEF(getColumnNumber)

deps/chakrashim/src/jsrtcontextshim.cc

@@ -76,7 +76,8 @@ ContextShim::ContextShim(IsolateShim * isolateShim,
       getIndexedOwnKeysFunction(JS_INVALID_REFERENCE),
       getStackTraceFunction(JS_INVALID_REFERENCE),
       getSymbolKeyForFunction(JS_INVALID_REFERENCE),
-      getSymbolForFunction(JS_INVALID_REFERENCE) {
+      getSymbolForFunction(JS_INVALID_REFERENCE),
+      ensureDebugFunction(JS_INVALID_REFERENCE) {
   memset(globalConstructor, 0, sizeof(globalConstructor));
   memset(globalPrototypeFunction, 0, sizeof(globalPrototypeFunction));
 }
@@ -578,6 +579,7 @@ CHAKRASHIM_FUNCTION_GETTER(getIndexedOwnKeys)
 CHAKRASHIM_FUNCTION_GETTER(getStackTrace)
 CHAKRASHIM_FUNCTION_GETTER(getSymbolKeyFor)
 CHAKRASHIM_FUNCTION_GETTER(getSymbolFor)
+CHAKRASHIM_FUNCTION_GETTER(ensureDebug)
 
 #define DEF_IS_TYPE(F) CHAKRASHIM_FUNCTION_GETTER(F)
 #include "jsrtcachedpropertyidref.inc"

deps/chakrashim/src/jsrtcontextshim.h

@@ -146,6 +146,7 @@ JsValueRef F##Function; \
   DECLARE_CHAKRASHIM_FUNCTION_GETTER(getStackTrace);
   DECLARE_CHAKRASHIM_FUNCTION_GETTER(getSymbolKeyFor);
   DECLARE_CHAKRASHIM_FUNCTION_GETTER(getSymbolFor);
+  DECLARE_CHAKRASHIM_FUNCTION_GETTER(ensureDebug);
 
 #define DEF_IS_TYPE(F) DECLARE_CHAKRASHIM_FUNCTION_GETTER(F)
 #include "jsrtcachedpropertyidref.inc"

deps/chakrashim/src/v8debug.cc

@@ -63,19 +63,17 @@ Local<Context> Debug::GetDebugContext(Isolate* isolate) {
     g_debugContext = *Context::New(isolate);
     JsAddRef(g_debugContext, nullptr);
 
+    Local<Object> global = Context::GetCurrent()->Global();
+
     // CHAKRA-TODO: Chakra doesn't fully implement the debugger without
     // --debug flag. Add a dummy 'Debug' on global object if it doesn't
     // already exist.
     {
       Context::Scope context_scope(g_debugContext);
-      wchar_t * debugScript = L""
-        "if(this['Debug'] == undefined) { "
-           "Object.defineProperty(this, 'Debug', { value: {}, "
-                "enumerable : false, configurable : false, writable : false "
-            "}); "
-         "}";
-      JsValueRef result;
-      if (JsRunScript(debugScript, JS_SOURCE_CONTEXT_NONE, L"", &result) != JsNoError) {
+      jsrt::ContextShim* contextShim = jsrt::ContextShim::GetCurrent();
+      JsValueRef ensureDebug = contextShim->GetensureDebugFunction();
+      JsValueRef unused;
+      if (jsrt::CallFunction(ensureDebug, *global, &unused) != JsNoError) {
         return Local<Context>();
       }
     }