From 4a891fa5c51628c1a830be0068f8cb580c16ff2b Mon Sep 17 00:00:00 2001
From: Jim Blandy <jimb@mozilla.com>
Date: Sat, 6 Jul 2019 21:26:45 +0000
Subject: [PATCH] Bug 1470558: Use Completion in Debugger.Object 'call' and
 'apply' methods. r=jorendorff

Differential Revision: https://phabricator.services.mozilla.com/D33078

--HG--
extra : moz-landing-system : lando
---
 js/src/vm/Debugger.cpp | 45 ++++++++++++++++++++++++++++--------------
 js/src/vm/Debugger.h   |  6 +++---
 2 files changed, 33 insertions(+), 18 deletions(-)

diff --git a/js/src/vm/Debugger.cpp b/js/src/vm/Debugger.cpp
index b89fcbd34474..711ac4974641 100644
--- a/js/src/vm/Debugger.cpp
+++ b/js/src/vm/Debugger.cpp
@@ -11502,7 +11502,13 @@ bool DebuggerObject::callMethod(JSContext* cx, unsigned argc, Value* vp) {
     }
   }
 
-  return object->call(cx, object, thisv, args, callArgs.rval());
+  Rooted<Maybe<Completion>> completion(
+      cx, DebuggerObject::call(cx, object, thisv, args));
+  if (!completion.get()) {
+    return false;
+  }
+
+  return completion->buildCompletionValue(cx, object->owner(), callArgs.rval());
 }
 
 /* static */
@@ -11573,7 +11579,13 @@ bool DebuggerObject::applyMethod(JSContext* cx, unsigned argc, Value* vp) {
     }
   }
 
-  return object->call(cx, object, thisv, args, callArgs.rval());
+  Rooted<Maybe<Completion>> completion(
+      cx, DebuggerObject::call(cx, object, thisv, args));
+  if (!completion.get()) {
+    return false;
+  }
+
+  return completion->buildCompletionValue(cx, object->owner(), callArgs.rval());
 }
 
 static void EnterDebuggeeObjectRealm(JSContext* cx, Maybe<AutoRealm>& ar,
@@ -12562,9 +12574,10 @@ Result<Completion> DebuggerObject::setProperty(JSContext* cx,
 }
 
 /* static */
-bool DebuggerObject::call(JSContext* cx, HandleDebuggerObject object,
-                          HandleValue thisv_, Handle<ValueVector> args,
-                          MutableHandleValue result) {
+Maybe<Completion> DebuggerObject::call(JSContext* cx,
+                                       HandleDebuggerObject object,
+                                       HandleValue thisv_,
+                                       Handle<ValueVector> args) {
   RootedObject referent(cx, object->referent());
   Debugger* dbg = object->owner();
 
@@ -12572,7 +12585,7 @@ bool DebuggerObject::call(JSContext* cx, HandleDebuggerObject object,
     JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
                               JSMSG_INCOMPATIBLE_PROTO, "Debugger.Object",
                               "call", referent->getClass()->name);
-    return false;
+    return Nothing();
   }
 
   RootedValue calleev(cx, ObjectValue(*referent));
@@ -12581,15 +12594,15 @@ bool DebuggerObject::call(JSContext* cx, HandleDebuggerObject object,
   // that is where any exceptions must be reported.
   RootedValue thisv(cx, thisv_);
   if (!dbg->unwrapDebuggeeValue(cx, &thisv)) {
-    return false;
+    return Nothing();
   }
   Rooted<ValueVector> args2(cx, ValueVector(cx));
   if (!args2.append(args.begin(), args.end())) {
-    return false;
+    return Nothing();
   }
   for (unsigned i = 0; i < args2.length(); ++i) {
     if (!dbg->unwrapDebuggeeValue(cx, args2[i])) {
-      return false;
+      return Nothing();
     }
   }
 
@@ -12600,18 +12613,18 @@ bool DebuggerObject::call(JSContext* cx, HandleDebuggerObject object,
   EnterDebuggeeObjectRealm(cx, ar, referent);
   if (!cx->compartment()->wrap(cx, &calleev) ||
       !cx->compartment()->wrap(cx, &thisv)) {
-    return false;
+    return Nothing();
   }
   for (unsigned i = 0; i < args2.length(); ++i) {
     if (!cx->compartment()->wrap(cx, args2[i])) {
-      return false;
+      return Nothing();
     }
   }
 
-  // Call the function. Use receiveCompletionValue to return to the debugger
-  // compartment and populate args.rval().
+  // Call the function.
   LeaveDebuggeeNoExecute nnx(cx);
 
+  RootedValue result(cx);
   bool ok;
   {
     InvokeArgs invokeArgs(cx);
@@ -12622,11 +12635,13 @@ bool DebuggerObject::call(JSContext* cx, HandleDebuggerObject object,
         invokeArgs[i].set(args2[i]);
       }
 
-      ok = js::Call(cx, calleev, thisv, invokeArgs, result);
+      ok = js::Call(cx, calleev, thisv, invokeArgs, &result);
     }
   }
 
-  return dbg->receiveCompletionValue(ar, ok, result, result);
+  Rooted<Completion> completion(cx, Completion::fromJSResult(cx, ok, result));
+  ar.reset();
+  return Some(std::move(completion.get()));
 }
 
 /* static */
diff --git a/js/src/vm/Debugger.h b/js/src/vm/Debugger.h
index 589ad93147f7..1b534eceead8 100644
--- a/js/src/vm/Debugger.h
+++ b/js/src/vm/Debugger.h
@@ -1869,9 +1869,9 @@ class DebuggerObject : public NativeObject {
   static MOZ_MUST_USE bool deleteProperty(JSContext* cx,
                                           HandleDebuggerObject object,
                                           HandleId id, ObjectOpResult& result);
-  static MOZ_MUST_USE bool call(JSContext* cx, HandleDebuggerObject object,
-                                HandleValue thisv, Handle<ValueVector> args,
-                                MutableHandleValue result);
+  static MOZ_MUST_USE mozilla::Maybe<Completion> call(
+      JSContext* cx, HandleDebuggerObject object, HandleValue thisv,
+      Handle<ValueVector> args);
   static MOZ_MUST_USE bool forceLexicalInitializationByName(
       JSContext* cx, HandleDebuggerObject object, HandleId id, bool& result);
   static MOZ_MUST_USE JS::Result<Completion> executeInGlobal(