gecko-dev/dom/plugins/base/nsJSNPRuntime.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "base/basictypes.h"

#include "jsfriendapi.h"

#include "nsAutoPtr.h"
#include "nsIInterfaceRequestorUtils.h"
#include "nsJSNPRuntime.h"
#include "nsNPAPIPlugin.h"
#include "nsNPAPIPluginInstance.h"
#include "nsIGlobalObject.h"
#include "nsIScriptGlobalObject.h"
#include "nsIScriptContext.h"
#include "nsDOMJSUtils.h"
#include "nsJSUtils.h"
#include "mozilla/dom/Document.h"
#include "nsIXPConnect.h"
#include "xpcpublic.h"
#include "nsIContent.h"
#include "nsPluginInstanceOwner.h"
#include "nsWrapperCacheInlines.h"
#include "js/GCHashTable.h"
#include "js/Symbol.h"
#include "js/TracingAPI.h"
#include "js/Wrapper.h"
#include "mozilla/HashFunctions.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/dom/ScriptSettings.h"

#define NPRUNTIME_JSCLASS_NAME "NPObject JS wrapper class"

using namespace mozilla::plugins::parent;
using namespace mozilla;

#include "mozilla/plugins/PluginScriptableObjectParent.h"
using mozilla::plugins::ParentNPObject;
using mozilla::plugins::PluginScriptableObjectParent;

struct JSObjWrapperHasher {
  typedef nsJSObjWrapperKey Key;
  typedef Key Lookup;

  static uint32_t hash(const Lookup &l) {
    return js::MovableCellHasher<JS::Heap<JSObject *>>::hash(l.mJSObj) ^
           HashGeneric(l.mNpp);
  }

  static bool match(const Key &k, const Lookup &l) {
    return js::MovableCellHasher<JS::Heap<JSObject *>>::match(k.mJSObj,
                                                              l.mJSObj) &&
           k.mNpp == l.mNpp;
  }
};

namespace JS {
template <>
struct GCPolicy<nsJSObjWrapper *> {
  static void trace(JSTracer *trc, nsJSObjWrapper **wrapper, const char *name) {
    MOZ_ASSERT(wrapper);
    MOZ_ASSERT(*wrapper);
    (*wrapper)->trace(trc);
  }
};
}  // namespace JS

class NPObjWrapperHashEntry : public PLDHashEntryHdr {
 public:
  NPObject *mNPObj;  // Must be the first member for the PLDHash stubs to work
  JS::TenuredHeap<JSObject *> mJSObj;
  NPP mNpp;
};

// Hash of JSObject wrappers that wraps JSObjects as NPObjects. There
// will be one wrapper per JSObject per plugin instance, i.e. if two
// plugins access the JSObject x, two wrappers for x will be
// created. This is needed to be able to properly drop the wrappers
// when a plugin is torn down in case there's a leak in the plugin (we
// don't want to leak the world just because a plugin leaks an
// NPObject).
typedef JS::GCHashMap<nsJSObjWrapperKey, nsJSObjWrapper *, JSObjWrapperHasher,
                      js::SystemAllocPolicy>
    JSObjWrapperTable;
static UniquePtr<JSObjWrapperTable> sJSObjWrappers;

// Whether it's safe to iterate sJSObjWrappers.  Set to true when sJSObjWrappers
// has been initialized and is not currently being enumerated.
static bool sJSObjWrappersAccessible = false;

// Hash of NPObject wrappers that wrap NPObjects as JSObjects.
static PLDHashTable *sNPObjWrappers;

// Global wrapper count. This includes JSObject wrappers *and*
// NPObject wrappers. When this count goes to zero, there are no more
// wrappers and we can kill off hash tables etc.
static int32_t sWrapperCount;

static bool sCallbackIsRegistered = false;

static nsTArray<NPObject *> *sDelayedReleases;

namespace {

inline bool NPObjectIsOutOfProcessProxy(NPObject *obj) {
  return obj->_class == PluginScriptableObjectParent::GetClass();
}

}  // namespace

// Helper class that suppresses any JS exceptions that were thrown while
// the plugin executed JS, if the nsJSObjWrapper has a destroy pending.
// Note that this class is the product (vestige?) of a long evolution in how
// error reporting worked, and hence the mIsDestroyPending check, and hence this
// class in general, may or may not actually be necessary.

class MOZ_STACK_CLASS AutoJSExceptionSuppressor {
 public:
  AutoJSExceptionSuppressor(dom::AutoEntryScript &aes, nsJSObjWrapper *aWrapper)
      : mAes(aes), mIsDestroyPending(aWrapper->mDestroyPending) {}

  ~AutoJSExceptionSuppressor() {
    if (mIsDestroyPending) {
      mAes.ClearException();
    }
  }

 protected:
  dom::AutoEntryScript &mAes;
  bool mIsDestroyPending;
};

NPClass nsJSObjWrapper::sJSObjWrapperNPClass = {
    NP_CLASS_STRUCT_VERSION,           nsJSObjWrapper::NP_Allocate,
    nsJSObjWrapper::NP_Deallocate,     nsJSObjWrapper::NP_Invalidate,
    nsJSObjWrapper::NP_HasMethod,      nsJSObjWrapper::NP_Invoke,
    nsJSObjWrapper::NP_InvokeDefault,  nsJSObjWrapper::NP_HasProperty,
    nsJSObjWrapper::NP_GetProperty,    nsJSObjWrapper::NP_SetProperty,
    nsJSObjWrapper::NP_RemoveProperty, nsJSObjWrapper::NP_Enumerate,
    nsJSObjWrapper::NP_Construct};

class NPObjWrapperProxyHandler : public js::BaseProxyHandler {
  static const char family;

 public:
  static const NPObjWrapperProxyHandler singleton;

  constexpr NPObjWrapperProxyHandler() : BaseProxyHandler(&family) {}

  bool defineProperty(JSContext *cx, JS::Handle<JSObject *> proxy,
                      JS::Handle<jsid> id,
                      JS::Handle<JS::PropertyDescriptor> desc,
                      JS::ObjectOpResult &result) const override {
    ::JS_ReportErrorASCII(cx,
                          "Trying to add unsupported property on NPObject!");
    return false;
  }

  bool getPrototypeIfOrdinary(
      JSContext *cx, JS::Handle<JSObject *> proxy, bool *isOrdinary,
      JS::MutableHandle<JSObject *> proto) const override {
    *isOrdinary = true;
    proto.set(js::GetStaticPrototype(proxy));
    return true;
  }

  bool isExtensible(JSContext *cx, JS::Handle<JSObject *> proxy,
                    bool *extensible) const override {
    // Needs to be extensible so nsObjectLoadingContent can mutate our
    // __proto__.
    *extensible = true;
    return true;
  }

  bool preventExtensions(JSContext *cx, JS::Handle<JSObject *> proxy,
                         JS::ObjectOpResult &result) const override {
    result.succeed();
    return true;
  }

  bool getOwnPropertyDescriptor(
      JSContext *cx, JS::Handle<JSObject *> proxy, JS::Handle<jsid> id,
      JS::MutableHandle<JS::PropertyDescriptor> desc) const override;

  bool ownPropertyKeys(JSContext *cx, JS::Handle<JSObject *> proxy,
                       JS::AutoIdVector &properties) const override;

  bool delete_(JSContext *cx, JS::Handle<JSObject *> proxy, JS::Handle<jsid> id,
               JS::ObjectOpResult &result) const override;

  bool get(JSContext *cx, JS::Handle<JSObject *> proxy,
           JS::Handle<JS::Value> receiver, JS::Handle<jsid> id,
           JS::MutableHandle<JS::Value> vp) const override;

  bool set(JSContext *cx, JS::Handle<JSObject *> proxy, JS::Handle<jsid> id,
           JS::Handle<JS::Value> vp, JS::Handle<JS::Value> receiver,
           JS::ObjectOpResult &result) const override;

  bool isCallable(JSObject *obj) const override { return true; }
  bool call(JSContext *cx, JS::Handle<JSObject *> proxy,
            const JS::CallArgs &args) const override;

  bool isConstructor(JSObject *obj) const override { return true; }
  bool construct(JSContext *cx, JS::Handle<JSObject *> proxy,
                 const JS::CallArgs &args) const override;

  bool finalizeInBackground(const JS::Value &priv) const override {
    return false;
  }
  void finalize(JSFreeOp *fop, JSObject *proxy) const override;

  size_t objectMoved(JSObject *obj, JSObject *old) const override;
};

const char NPObjWrapperProxyHandler::family = 0;
const NPObjWrapperProxyHandler NPObjWrapperProxyHandler::singleton;

static bool NPObjWrapper_Resolve(JSContext *cx, JS::Handle<JSObject *> obj,
                                 JS::Handle<jsid> id, bool *resolved,
                                 JS::MutableHandle<JSObject *> method);

static bool NPObjWrapper_toPrimitive(JSContext *cx, unsigned argc,
                                     JS::Value *vp);

static bool CreateNPObjectMember(NPP npp, JSContext *cx,
                                 JS::Handle<JSObject *> obj, NPObject *npobj,
                                 JS::Handle<jsid> id,
                                 NPVariant *getPropertyResult,
                                 JS::MutableHandle<JS::Value> vp);

const js::Class sNPObjWrapperProxyClass =
    PROXY_CLASS_DEF(NPRUNTIME_JSCLASS_NAME, JSCLASS_HAS_RESERVED_SLOTS(1));

typedef struct NPObjectMemberPrivate {
  JS::Heap<JSObject *> npobjWrapper;
  JS::Heap<JS::Value> fieldValue;
  JS::Heap<jsid> methodName;
  NPP npp;
} NPObjectMemberPrivate;

static void NPObjectMember_Finalize(JSFreeOp *fop, JSObject *obj);

static bool NPObjectMember_Call(JSContext *cx, unsigned argc, JS::Value *vp);

static void NPObjectMember_Trace(JSTracer *trc, JSObject *obj);

static bool NPObjectMember_toPrimitive(JSContext *cx, unsigned argc,
                                       JS::Value *vp);

static const JSClassOps sNPObjectMemberClassOps = {nullptr,
                                                   nullptr,
                                                   nullptr,
                                                   nullptr,
                                                   nullptr,
                                                   nullptr,
                                                   NPObjectMember_Finalize,
                                                   NPObjectMember_Call,
                                                   nullptr,
                                                   nullptr,
                                                   NPObjectMember_Trace};

static const JSClass sNPObjectMemberClass = {
    "NPObject Ambiguous Member class",
    JSCLASS_HAS_PRIVATE | JSCLASS_FOREGROUND_FINALIZE,
    &sNPObjectMemberClassOps};

static void OnWrapperDestroyed();

static void TraceJSObjWrappers(JSTracer *trc, void *data) {
  if (sJSObjWrappers) {
    sJSObjWrappers->trace(trc);
  }
}

static void DelayedReleaseGCCallback(JSGCStatus status) {
  if (JSGC_END == status) {
    // Take ownership of sDelayedReleases and null it out now. The
    // _releaseobject call below can reenter GC and double-free these objects.
    nsAutoPtr<nsTArray<NPObject *>> delayedReleases(sDelayedReleases);
    sDelayedReleases = nullptr;

    if (delayedReleases) {
      for (uint32_t i = 0; i < delayedReleases->Length(); ++i) {
        NPObject *obj = (*delayedReleases)[i];
        if (obj) _releaseobject(obj);
        OnWrapperDestroyed();
      }
    }
  }
}

static bool RegisterGCCallbacks() {
  if (sCallbackIsRegistered) {
    return true;
  }

  // Register a callback to trace wrapped JSObjects.
  JSContext *cx = dom::danger::GetJSContext();
  if (!JS_AddExtraGCRootsTracer(cx, TraceJSObjWrappers, nullptr)) {
    return false;
  }

  // Register our GC callback to perform delayed destruction of finalized
  // NPObjects.
  xpc::AddGCCallback(DelayedReleaseGCCallback);

  sCallbackIsRegistered = true;

  return true;
}

static void UnregisterGCCallbacks() {
  MOZ_ASSERT(sCallbackIsRegistered);

  // Remove tracing callback.
  JSContext *cx = dom::danger::GetJSContext();
  JS_RemoveExtraGCRootsTracer(cx, TraceJSObjWrappers, nullptr);

  // Remove delayed destruction callback.
  if (sCallbackIsRegistered) {
    xpc::RemoveGCCallback(DelayedReleaseGCCallback);
    sCallbackIsRegistered = false;
  }
}

static bool CreateJSObjWrapperTable() {
  MOZ_ASSERT(!sJSObjWrappersAccessible);
  MOZ_ASSERT(!sJSObjWrappers);

  if (!RegisterGCCallbacks()) {
    return false;
  }

  sJSObjWrappers = MakeUnique<JSObjWrapperTable>();
  sJSObjWrappersAccessible = true;
  return true;
}

static void DestroyJSObjWrapperTable() {
  MOZ_ASSERT(sJSObjWrappersAccessible);
  MOZ_ASSERT(sJSObjWrappers);
  MOZ_ASSERT(sJSObjWrappers->count() == 0);

  // No more wrappers. Delete the table.
  sJSObjWrappers = nullptr;
  sJSObjWrappersAccessible = false;
}

static bool CreateNPObjWrapperTable() {
  MOZ_ASSERT(!sNPObjWrappers);

  if (!RegisterGCCallbacks()) {
    return false;
  }

  sNPObjWrappers =
      new PLDHashTable(PLDHashTable::StubOps(), sizeof(NPObjWrapperHashEntry));
  return true;
}

static void DestroyNPObjWrapperTable() {
  MOZ_ASSERT(sNPObjWrappers->EntryCount() == 0);

  delete sNPObjWrappers;
  sNPObjWrappers = nullptr;
}

static void OnWrapperCreated() { ++sWrapperCount; }

static void OnWrapperDestroyed() {
  NS_ASSERTION(sWrapperCount, "Whaaa, unbalanced created/destroyed calls!");

  if (--sWrapperCount == 0) {
    if (sJSObjWrappersAccessible) {
      DestroyJSObjWrapperTable();
    }

    if (sNPObjWrappers) {
      // No more wrappers, and our hash was initialized. Finish the
      // hash to prevent leaking it.
      DestroyNPObjWrapperTable();
    }

    UnregisterGCCallbacks();
  }
}

namespace mozilla {
namespace plugins {
namespace parent {

static nsIGlobalObject *GetGlobalObject(NPP npp) {
  NS_ENSURE_TRUE(npp, nullptr);

  nsNPAPIPluginInstance *inst = (nsNPAPIPluginInstance *)npp->ndata;
  NS_ENSURE_TRUE(inst, nullptr);

  RefPtr<nsPluginInstanceOwner> owner = inst->GetOwner();
  NS_ENSURE_TRUE(owner, nullptr);

  nsCOMPtr<dom::Document> doc;
  owner->GetDocument(getter_AddRefs(doc));
  NS_ENSURE_TRUE(doc, nullptr);

  return doc->GetScopeObject();
}

}  // namespace parent
}  // namespace plugins
}  // namespace mozilla

static NPP LookupNPP(NPObject *npobj);

static JS::Value NPVariantToJSVal(NPP npp, JSContext *cx,
                                  const NPVariant *variant) {
  switch (variant->type) {
    case NPVariantType_Void:
      return JS::UndefinedValue();
    case NPVariantType_Null:
      return JS::NullValue();
    case NPVariantType_Bool:
      return JS::BooleanValue(NPVARIANT_TO_BOOLEAN(*variant));
    case NPVariantType_Int32: {
      // Don't use INT_TO_JSVAL directly to prevent bugs when dealing
      // with ints larger than what fits in a integer JS::Value.
      return ::JS_NumberValue(NPVARIANT_TO_INT32(*variant));
    }
    case NPVariantType_Double: {
      return ::JS_NumberValue(NPVARIANT_TO_DOUBLE(*variant));
    }
    case NPVariantType_String: {
      const NPString *s = &NPVARIANT_TO_STRING(*variant);
      NS_ConvertUTF8toUTF16 utf16String(s->UTF8Characters, s->UTF8Length);

      JSString *str =
          ::JS_NewUCStringCopyN(cx, utf16String.get(), utf16String.Length());

      if (str) {
        return JS::StringValue(str);
      }

      break;
    }
    case NPVariantType_Object: {
      if (npp) {
        JSObject *obj = nsNPObjWrapper::GetNewOrUsed(
            npp, cx, NPVARIANT_TO_OBJECT(*variant));

        if (obj) {
          return JS::ObjectValue(*obj);
        }
      }

      NS_ERROR("Error wrapping NPObject!");

      break;
    }
    default:
      NS_ERROR("Unknown NPVariant type!");
  }

  NS_ERROR("Unable to convert NPVariant to jsval!");

  return JS::UndefinedValue();
}

bool JSValToNPVariant(NPP npp, JSContext *cx, const JS::Value &val,
                      NPVariant *variant) {
  NS_ASSERTION(npp, "Must have an NPP to wrap a jsval!");

  if (val.isPrimitive()) {
    if (val.isUndefined()) {
      VOID_TO_NPVARIANT(*variant);
    } else if (val.isNull()) {
      NULL_TO_NPVARIANT(*variant);
    } else if (val.isBoolean()) {
      BOOLEAN_TO_NPVARIANT(val.toBoolean(), *variant);
    } else if (val.isInt32()) {
      INT32_TO_NPVARIANT(val.toInt32(), *variant);
    } else if (val.isDouble()) {
      double d = val.toDouble();
      int i;
      if (JS_DoubleIsInt32(d, &i)) {
        INT32_TO_NPVARIANT(i, *variant);
      } else {
        DOUBLE_TO_NPVARIANT(d, *variant);
      }
    } else if (val.isString()) {
      JSString *jsstr = val.toString();

      nsAutoJSString str;
      if (!str.init(cx, jsstr)) {
        return false;
      }

      uint32_t len;
      char *p = ToNewUTF8String(str, &len);

      if (!p) {
        return false;
      }

      STRINGN_TO_NPVARIANT(p, len, *variant);
    } else {
      NS_ERROR("Unknown primitive type!");

      return false;
    }

    return true;
  }

  // The reflected plugin object may be in another compartment if the plugin
  // element has since been adopted into a new document. We don't bother
  // transplanting the plugin objects, and just do a unwrap with security
  // checks if we encounter one of them as an argument. If the unwrap fails,
  // we run with the original wrapped object, since sometimes there are
  // legitimate cases where a security wrapper ends up here (for example,
  // Location objects, which are _always_ behind security wrappers).
  JS::Rooted<JSObject *> obj(cx, &val.toObject());
  JS::Rooted<JSObject *> global(cx);
  obj = js::CheckedUnwrap(obj);
  if (obj) {
    global = JS::GetNonCCWObjectGlobal(obj);
  } else {
    obj = &val.toObject();
    global = JS::CurrentGlobalOrNull(cx);
  }

  NPObject *npobj = nsJSObjWrapper::GetNewOrUsed(npp, obj, global);
  if (!npobj) {
    return false;
  }

  // Pass over ownership of npobj to *variant
  OBJECT_TO_NPVARIANT(npobj, *variant);

  return true;
}

static void ThrowJSExceptionASCII(JSContext *cx, const char *message) {
  const char *ex = PeekException();

  if (ex) {
    nsAutoString ucex;

    if (message) {
      AppendASCIItoUTF16(mozilla::MakeStringSpan(message), ucex);

      ucex.AppendLiteral(" [plugin exception: ");
    }

    AppendUTF8toUTF16(mozilla::MakeStringSpan(ex), ucex);

    if (message) {
      ucex.AppendLiteral("].");
    }

    JSString *str = ::JS_NewUCStringCopyN(cx, ucex.get(), ucex.Length());

    if (str) {
      JS::Rooted<JS::Value> exn(cx, JS::StringValue(str));
      ::JS_SetPendingException(cx, exn);
    }

    PopException();
  } else {
    ::JS_ReportErrorASCII(cx, "%s", message);
  }
}

static bool ReportExceptionIfPending(JSContext *cx) {
  const char *ex = PeekException();

  if (!ex) {
    return true;
  }

  ThrowJSExceptionASCII(cx, nullptr);

  return false;
}

nsJSObjWrapper::nsJSObjWrapper(NPP npp)
    : mJSObj(nullptr),
      mJSObjGlobal(nullptr),
      mNpp(npp),
      mDestroyPending(false) {
  MOZ_COUNT_CTOR(nsJSObjWrapper);
  OnWrapperCreated();
}

nsJSObjWrapper::~nsJSObjWrapper() {
  MOZ_COUNT_DTOR(nsJSObjWrapper);

  // Invalidate first, since it relies on sJSObjWrappers.
  NP_Invalidate(this);

  OnWrapperDestroyed();
}

// static
NPObject *nsJSObjWrapper::NP_Allocate(NPP npp, NPClass *aClass) {
  NS_ASSERTION(aClass == &sJSObjWrapperNPClass,
               "Huh, wrong class passed to NP_Allocate()!!!");

  return new nsJSObjWrapper(npp);
}

// static
void nsJSObjWrapper::NP_Deallocate(NPObject *npobj) {
  // nsJSObjWrapper::~nsJSObjWrapper() will call NP_Invalidate().
  delete (nsJSObjWrapper *)npobj;
}

// static
void nsJSObjWrapper::NP_Invalidate(NPObject *npobj) {
  nsJSObjWrapper *jsnpobj = (nsJSObjWrapper *)npobj;

  if (jsnpobj && jsnpobj->mJSObj) {
    if (sJSObjWrappersAccessible) {
      // Remove the wrapper from the hash
      nsJSObjWrapperKey key(jsnpobj->mJSObj, jsnpobj->mNpp);
      JSObjWrapperTable::Ptr ptr = sJSObjWrappers->lookup(key);
      MOZ_ASSERT(ptr.found());
      sJSObjWrappers->remove(ptr);
    }

    // Forget our reference to the JSObject.
    jsnpobj->mJSObj = nullptr;
    jsnpobj->mJSObjGlobal = nullptr;
  }
}

static bool GetProperty(JSContext *cx, JSObject *objArg, NPIdentifier npid,
                        JS::MutableHandle<JS::Value> rval) {
  NS_ASSERTION(NPIdentifierIsInt(npid) || NPIdentifierIsString(npid),
               "id must be either string or int!\n");
  JS::Rooted<JSObject *> obj(cx, objArg);
  JS::Rooted<jsid> id(cx, NPIdentifierToJSId(npid));
  return ::JS_GetPropertyById(cx, obj, id, rval);
}

static void MarkCrossZoneNPIdentifier(JSContext *cx, NPIdentifier npid) {
  JS_MarkCrossZoneId(cx, NPIdentifierToJSId(npid));
}

// static
bool nsJSObjWrapper::NP_HasMethod(NPObject *npobj, NPIdentifier id) {
  NPP npp = NPPStack::Peek();
  nsIGlobalObject *globalObject = GetGlobalObject(npp);
  if (NS_WARN_IF(!globalObject)) {
    return false;
  }

  dom::AutoEntryScript aes(globalObject, "NPAPI HasMethod");
  JSContext *cx = aes.cx();

  if (!npobj) {
    ThrowJSExceptionASCII(cx, "Null npobj in nsJSObjWrapper::NP_HasMethod!");

    return false;
  }

  nsJSObjWrapper *npjsobj = (nsJSObjWrapper *)npobj;

  JSAutoRealm ar(cx, npjsobj->mJSObjGlobal);
  MarkCrossZoneNPIdentifier(cx, id);

  AutoJSExceptionSuppressor suppressor(aes, npjsobj);

  JS::Rooted<JS::Value> v(cx);
  bool ok = GetProperty(cx, npjsobj->mJSObj, id, &v);

  return ok && !v.isPrimitive() &&
         ::JS_ObjectIsFunction(cx, v.toObjectOrNull());
}

static bool doInvoke(NPObject *npobj, NPIdentifier method,
                     const NPVariant *args, uint32_t argCount, bool ctorCall,
                     NPVariant *result) {
  NPP npp = NPPStack::Peek();

  nsCOMPtr<nsIGlobalObject> globalObject = GetGlobalObject(npp);
  if (NS_WARN_IF(!globalObject)) {
    return false;
  }

  // We're about to run script via JS_CallFunctionValue, so we need an
  // AutoEntryScript. NPAPI plugins are Gecko-specific and not in any spec.
  dom::AutoEntryScript aes(globalObject, "NPAPI doInvoke");
  JSContext *cx = aes.cx();

  if (!npobj || !result) {
    ThrowJSExceptionASCII(cx, "Null npobj, or result in doInvoke!");

    return false;
  }

  // Initialize *result
  VOID_TO_NPVARIANT(*result);

  nsJSObjWrapper *npjsobj = (nsJSObjWrapper *)npobj;

  JS::Rooted<JSObject *> jsobj(cx, npjsobj->mJSObj);
  JSAutoRealm ar(cx, npjsobj->mJSObjGlobal);
  MarkCrossZoneNPIdentifier(cx, method);
  JS::Rooted<JS::Value> fv(cx);

  AutoJSExceptionSuppressor suppressor(aes, npjsobj);

  if (method != NPIdentifier_VOID) {
    if (!GetProperty(cx, jsobj, method, &fv) ||
        ::JS_TypeOfValue(cx, fv) != JSTYPE_FUNCTION) {
      return false;
    }
  } else {
    fv.setObject(*jsobj);
  }

  // Convert args
  JS::AutoValueVector jsargs(cx);
  if (!jsargs.reserve(argCount)) {
    ::JS_ReportOutOfMemory(cx);
    return false;
  }
  for (uint32_t i = 0; i < argCount; ++i) {
    jsargs.infallibleAppend(NPVariantToJSVal(npp, cx, args + i));
  }

  JS::Rooted<JS::Value> v(cx);
  bool ok = false;

  if (ctorCall) {
    JSObject *newObj = ::JS_New(cx, jsobj, jsargs);

    if (newObj) {
      v.setObject(*newObj);
      ok = true;
    }
  } else {
    ok = ::JS_CallFunctionValue(cx, jsobj, fv, jsargs, &v);
  }

  if (ok) ok = JSValToNPVariant(npp, cx, v, result);

  return ok;
}

// static
bool nsJSObjWrapper::NP_Invoke(NPObject *npobj, NPIdentifier method,
                               const NPVariant *args, uint32_t argCount,
                               NPVariant *result) {
  if (method == NPIdentifier_VOID) {
    return false;
  }

  return doInvoke(npobj, method, args, argCount, false, result);
}

// static
bool nsJSObjWrapper::NP_InvokeDefault(NPObject *npobj, const NPVariant *args,
                                      uint32_t argCount, NPVariant *result) {
  return doInvoke(npobj, NPIdentifier_VOID, args, argCount, false, result);
}

// static
bool nsJSObjWrapper::NP_HasProperty(NPObject *npobj, NPIdentifier npid) {
  NPP npp = NPPStack::Peek();
  nsIGlobalObject *globalObject = GetGlobalObject(npp);
  if (NS_WARN_IF(!globalObject)) {
    return false;
  }

  dom::AutoEntryScript aes(globalObject, "NPAPI HasProperty");
  JSContext *cx = aes.cx();

  if (!npobj) {
    ThrowJSExceptionASCII(cx, "Null npobj in nsJSObjWrapper::NP_HasProperty!");

    return false;
  }

  nsJSObjWrapper *npjsobj = (nsJSObjWrapper *)npobj;
  bool found, ok = false;

  AutoJSExceptionSuppressor suppressor(aes, npjsobj);
  JS::Rooted<JSObject *> jsobj(cx, npjsobj->mJSObj);
  JSAutoRealm ar(cx, npjsobj->mJSObjGlobal);
  MarkCrossZoneNPIdentifier(cx, npid);

  NS_ASSERTION(NPIdentifierIsInt(npid) || NPIdentifierIsString(npid),
               "id must be either string or int!\n");
  JS::Rooted<jsid> id(cx, NPIdentifierToJSId(npid));
  ok = ::JS_HasPropertyById(cx, jsobj, id, &found);
  return ok && found;
}

// static
bool nsJSObjWrapper::NP_GetProperty(NPObject *npobj, NPIdentifier id,
                                    NPVariant *result) {
  NPP npp = NPPStack::Peek();

  nsCOMPtr<nsIGlobalObject> globalObject = GetGlobalObject(npp);
  if (NS_WARN_IF(!globalObject)) {
    return false;
  }

  // We're about to run script via JS_CallFunctionValue, so we need an
  // AutoEntryScript. NPAPI plugins are Gecko-specific and not in any spec.
  dom::AutoEntryScript aes(globalObject, "NPAPI get");
  JSContext *cx = aes.cx();

  if (!npobj) {
    ThrowJSExceptionASCII(cx, "Null npobj in nsJSObjWrapper::NP_GetProperty!");

    return false;
  }

  nsJSObjWrapper *npjsobj = (nsJSObjWrapper *)npobj;

  AutoJSExceptionSuppressor suppressor(aes, npjsobj);
  JSAutoRealm ar(cx, npjsobj->mJSObjGlobal);
  MarkCrossZoneNPIdentifier(cx, id);

  JS::Rooted<JS::Value> v(cx);
  return (GetProperty(cx, npjsobj->mJSObj, id, &v) &&
          JSValToNPVariant(npp, cx, v, result));
}

// static
bool nsJSObjWrapper::NP_SetProperty(NPObject *npobj, NPIdentifier npid,
                                    const NPVariant *value) {
  NPP npp = NPPStack::Peek();

  nsCOMPtr<nsIGlobalObject> globalObject = GetGlobalObject(npp);
  if (NS_WARN_IF(!globalObject)) {
    return false;
  }

  // We're about to run script via JS_CallFunctionValue, so we need an
  // AutoEntryScript. NPAPI plugins are Gecko-specific and not in any spec.
  dom::AutoEntryScript aes(globalObject, "NPAPI set");
  JSContext *cx = aes.cx();

  if (!npobj) {
    ThrowJSExceptionASCII(cx, "Null npobj in nsJSObjWrapper::NP_SetProperty!");

    return false;
  }

  nsJSObjWrapper *npjsobj = (nsJSObjWrapper *)npobj;
  bool ok = false;

  AutoJSExceptionSuppressor suppressor(aes, npjsobj);
  JS::Rooted<JSObject *> jsObj(cx, npjsobj->mJSObj);
  JSAutoRealm ar(cx, npjsobj->mJSObjGlobal);
  MarkCrossZoneNPIdentifier(cx, npid);

  JS::Rooted<JS::Value> v(cx, NPVariantToJSVal(npp, cx, value));

  NS_ASSERTION(NPIdentifierIsInt(npid) || NPIdentifierIsString(npid),
               "id must be either string or int!\n");
  JS::Rooted<jsid> id(cx, NPIdentifierToJSId(npid));
  ok = ::JS_SetPropertyById(cx, jsObj, id, v);

  return ok;
}

// static
bool nsJSObjWrapper::NP_RemoveProperty(NPObject *npobj, NPIdentifier npid) {
  NPP npp = NPPStack::Peek();
  nsIGlobalObject *globalObject = GetGlobalObject(npp);
  if (NS_WARN_IF(!globalObject)) {
    return false;
  }

  dom::AutoEntryScript aes(globalObject, "NPAPI RemoveProperty");
  JSContext *cx = aes.cx();

  if (!npobj) {
    ThrowJSExceptionASCII(cx,
                          "Null npobj in nsJSObjWrapper::NP_RemoveProperty!");

    return false;
  }

  nsJSObjWrapper *npjsobj = (nsJSObjWrapper *)npobj;

  AutoJSExceptionSuppressor suppressor(aes, npjsobj);
  JS::ObjectOpResult result;
  JS::Rooted<JSObject *> obj(cx, npjsobj->mJSObj);
  JSAutoRealm ar(cx, npjsobj->mJSObjGlobal);
  MarkCrossZoneNPIdentifier(cx, npid);

  NS_ASSERTION(NPIdentifierIsInt(npid) || NPIdentifierIsString(npid),
               "id must be either string or int!\n");
  JS::Rooted<jsid> id(cx, NPIdentifierToJSId(npid));
  if (!::JS_DeletePropertyById(cx, obj, id, result)) return false;

  if (result) {
    // FIXME: See bug 425823, we shouldn't need to do this, and once
    // that bug is fixed we can remove this code.
    bool hasProp;
    if (!::JS_HasPropertyById(cx, obj, id, &hasProp)) return false;
    if (!hasProp) return true;

    // The property might have been deleted, but it got
    // re-resolved, so no, it's not really deleted.
    result.failCantDelete();
  }

  return result.reportError(cx, obj, id);
}

// static
bool nsJSObjWrapper::NP_Enumerate(NPObject *npobj, NPIdentifier **idarray,
                                  uint32_t *count) {
  NPP npp = NPPStack::Peek();
  nsIGlobalObject *globalObject = GetGlobalObject(npp);
  if (NS_WARN_IF(!globalObject)) {
    return false;
  }

  dom::AutoEntryScript aes(globalObject, "NPAPI Enumerate");
  JSContext *cx = aes.cx();

  *idarray = 0;
  *count = 0;

  if (!npobj) {
    ThrowJSExceptionASCII(cx, "Null npobj in nsJSObjWrapper::NP_Enumerate!");

    return false;
  }

  nsJSObjWrapper *npjsobj = (nsJSObjWrapper *)npobj;

  AutoJSExceptionSuppressor suppressor(aes, npjsobj);
  JS::Rooted<JSObject *> jsobj(cx, npjsobj->mJSObj);
  JSAutoRealm ar(cx, npjsobj->mJSObjGlobal);

  JS::Rooted<JS::IdVector> ida(cx, JS::IdVector(cx));
  if (!JS_Enumerate(cx, jsobj, &ida)) {
    return false;
  }

  *count = ida.length();
  *idarray = (NPIdentifier *)malloc(*count * sizeof(NPIdentifier));
  if (!*idarray) {
    ThrowJSExceptionASCII(cx, "Memory allocation failed for NPIdentifier!");
    return false;
  }

  for (uint32_t i = 0; i < *count; i++) {
    JS::Rooted<JS::Value> v(cx);
    if (!JS_IdToValue(cx, ida[i], &v)) {
      free(*idarray);
      return false;
    }

    NPIdentifier id;
    if (v.isString()) {
      JS::Rooted<JSString *> str(cx, v.toString());
      str = JS_AtomizeAndPinJSString(cx, str);
      if (!str) {
        free(*idarray);
        return false;
      }
      id = StringToNPIdentifier(cx, str);
    } else {
      NS_ASSERTION(v.isInt32(),
                   "The element in ida must be either string or int!\n");
      id = IntToNPIdentifier(v.toInt32());
    }

    (*idarray)[i] = id;
  }

  return true;
}

// static
bool nsJSObjWrapper::NP_Construct(NPObject *npobj, const NPVariant *args,
                                  uint32_t argCount, NPVariant *result) {
  return doInvoke(npobj, NPIdentifier_VOID, args, argCount, true, result);
}

// Look up or create an NPObject that wraps the JSObject obj.

// static
NPObject *nsJSObjWrapper::GetNewOrUsed(NPP npp, JS::Handle<JSObject *> obj,
                                       JS::Handle<JSObject *> objGlobal) {
  if (!npp) {
    NS_ERROR("Null NPP passed to nsJSObjWrapper::GetNewOrUsed()!");

    return nullptr;
  }

  MOZ_ASSERT(JS_IsGlobalObject(objGlobal));
  MOZ_RELEASE_ASSERT(js::GetObjectCompartment(obj) ==
                     js::GetObjectCompartment(objGlobal));

  // No need to enter the right compartment here as we only get the
  // class and private from the JSObject, neither of which cares about
  // compartments.

  if (nsNPObjWrapper::IsWrapper(obj)) {
    // obj is one of our own, its private data is the NPObject we're
    // looking for.

    NPObject *npobj = (NPObject *)js::GetProxyPrivate(obj).toPrivate();

    // If the private is null, that means that the object has already been torn
    // down, possible because the owning plugin was destroyed (there can be
    // multiple plugins, so the fact that it was destroyed does not prevent one
    // of its dead JS objects from being passed to another plugin). There's not
    // much use in wrapping such a dead object, so we just return null, causing
    // us to throw.
    if (!npobj) return nullptr;

    if (LookupNPP(npobj) == npp) return _retainobject(npobj);
  }

  if (!sJSObjWrappers) {
    // No hash yet (or any more), initialize it.
    if (!CreateJSObjWrapperTable()) return nullptr;
  }
  MOZ_ASSERT(sJSObjWrappersAccessible);

  JSObjWrapperTable::Ptr p =
      sJSObjWrappers->lookup(nsJSObjWrapperKey(obj, npp));
  if (p) {
    MOZ_ASSERT(p->value());
    // Found a live nsJSObjWrapper, return it.

    return _retainobject(p->value());
  }

  // No existing nsJSObjWrapper, create one.

  nsJSObjWrapper *wrapper =
      (nsJSObjWrapper *)_createobject(npp, &sJSObjWrapperNPClass);

  if (!wrapper) {
    // Out of memory, entry not yet added to table.
    return nullptr;
  }

  wrapper->mJSObj = obj;
  wrapper->mJSObjGlobal = objGlobal;

  // Insert the new wrapper into the hashtable, rooting the JSObject. Its
  // lifetime is now tied to that of the NPObject.
  if (!sJSObjWrappers->putNew(nsJSObjWrapperKey(obj, npp), wrapper)) {
    // Out of memory, free the wrapper we created.
    _releaseobject(wrapper);
    return nullptr;
  }

  return wrapper;
}

// Climb the prototype chain, unwrapping as necessary until we find an NP object
// wrapper.
//
// Because this function unwraps, its return value must be wrapped for the cx
// compartment for callers that plan to hold onto the result or do anything
// substantial with it.
static JSObject *GetNPObjectWrapper(JSContext *cx, JS::Handle<JSObject *> aObj,
                                    bool wrapResult = true) {
  JS::Rooted<JSObject *> obj(cx, aObj);

  while (obj && (obj = js::CheckedUnwrap(obj))) {
    if (nsNPObjWrapper::IsWrapper(obj)) {
      if (wrapResult && !JS_WrapObject(cx, &obj)) {
        return nullptr;
      }
      return obj;
    }

    JSAutoRealm ar(cx, obj);
    if (!::JS_GetPrototype(cx, obj, &obj)) {
      return nullptr;
    }
  }
  return nullptr;
}

static NPObject *GetNPObject(JSContext *cx, JS::Handle<JSObject *> aObj) {
  JS::Rooted<JSObject *> obj(cx, aObj);
  obj = GetNPObjectWrapper(cx, obj, /* wrapResult = */ false);
  if (!obj) {
    return nullptr;
  }

  return (NPObject *)js::GetProxyPrivate(obj).toPrivate();
}

static JSObject *NPObjWrapper_GetResolvedProps(JSContext *cx,
                                               JS::Handle<JSObject *> obj) {
  JS::Value slot = js::GetProxyReservedSlot(obj, 0);
  if (slot.isObject()) return &slot.toObject();

  MOZ_ASSERT(slot.isUndefined());

  JSObject *res = JS_NewObject(cx, nullptr);
  if (!res) return nullptr;

  SetProxyReservedSlot(obj, 0, JS::ObjectValue(*res));
  return res;
}

bool NPObjWrapperProxyHandler::delete_(JSContext *cx,
                                       JS::Handle<JSObject *> proxy,
                                       JS::Handle<jsid> id,
                                       JS::ObjectOpResult &result) const {
  NPObject *npobj = GetNPObject(cx, proxy);

  if (!npobj || !npobj->_class || !npobj->_class->hasProperty ||
      !npobj->_class->removeProperty) {
    ThrowJSExceptionASCII(cx, "Bad NPObject as private data!");

    return false;
  }

  JS::Rooted<JSObject *> resolvedProps(
      cx, NPObjWrapper_GetResolvedProps(cx, proxy));
  if (!resolvedProps) return false;
  if (!JS_DeletePropertyById(cx, resolvedProps, id, result)) return false;

  PluginDestructionGuard pdg(LookupNPP(npobj));

  NPIdentifier identifier = JSIdToNPIdentifier(id);

  if (!NPObjectIsOutOfProcessProxy(npobj)) {
    bool hasProperty = npobj->_class->hasProperty(npobj, identifier);
    if (!ReportExceptionIfPending(cx)) return false;

    if (!hasProperty) return result.succeed();
  }

  // This removeProperty hook may throw an exception and return false; or just
  // return false without an exception pending, which behaves like `delete
  // obj.prop` returning false: in strict mode it becomes a TypeError. Legacy
  // code---nothing else that uses the JSAPI works this way anymore.
  bool succeeded = npobj->_class->removeProperty(npobj, identifier);
  if (!ReportExceptionIfPending(cx)) return false;
  return succeeded ? result.succeed() : result.failCantDelete();
}

bool NPObjWrapperProxyHandler::set(JSContext *cx, JS::Handle<JSObject *> proxy,
                                   JS::Handle<jsid> id,
                                   JS::Handle<JS::Value> vp,
                                   JS::Handle<JS::Value> receiver,
                                   JS::ObjectOpResult &result) const {
  NPObject *npobj = GetNPObject(cx, proxy);

  if (!npobj || !npobj->_class || !npobj->_class->hasProperty ||
      !npobj->_class->setProperty) {
    ThrowJSExceptionASCII(cx, "Bad NPObject as private data!");

    return false;
  }

  // Find out what plugin (NPP) is the owner of the object we're
  // manipulating, and make it own any JSObject wrappers created here.
  NPP npp = LookupNPP(npobj);

  if (!npp) {
    ThrowJSExceptionASCII(cx, "No NPP found for NPObject!");

    return false;
  }

  {
    bool resolved = false;
    JS::Rooted<JSObject *> method(cx);
    if (!NPObjWrapper_Resolve(cx, proxy, id, &resolved, &method)) return false;
    if (!resolved) {
      // We don't have a property/method with this id. Forward to the prototype
      // chain.
      return js::BaseProxyHandler::set(cx, proxy, id, vp, receiver, result);
    }
  }

  PluginDestructionGuard pdg(npp);

  NPIdentifier identifier = JSIdToNPIdentifier(id);

  if (!NPObjectIsOutOfProcessProxy(npobj)) {
    bool hasProperty = npobj->_class->hasProperty(npobj, identifier);
    if (!ReportExceptionIfPending(cx)) return false;

    if (!hasProperty) {
      ThrowJSExceptionASCII(cx,
                            "Trying to set unsupported property on NPObject!");

      return false;
    }
  }

  NPVariant npv;
  if (!JSValToNPVariant(npp, cx, vp, &npv)) {
    ThrowJSExceptionASCII(cx, "Error converting jsval to NPVariant!");

    return false;
  }

  bool ok = npobj->_class->setProperty(npobj, identifier, &npv);
  _releasevariantvalue(&npv);  // Release the variant
  if (!ReportExceptionIfPending(cx)) return false;

  if (!ok) {
    ThrowJSExceptionASCII(cx, "Error setting property on NPObject!");

    return false;
  }

  return result.succeed();
}

static bool CallNPMethod(JSContext *cx, unsigned argc, JS::Value *vp);

bool NPObjWrapperProxyHandler::get(JSContext *cx, JS::Handle<JSObject *> proxy,
                                   JS::Handle<JS::Value> receiver,
                                   JS::Handle<jsid> id,
                                   JS::MutableHandle<JS::Value> vp) const {
  NPObject *npobj = GetNPObject(cx, proxy);

  if (!npobj || !npobj->_class || !npobj->_class->hasProperty ||
      !npobj->_class->hasMethod || !npobj->_class->getProperty) {
    ThrowJSExceptionASCII(cx, "Bad NPObject as private data!");

    return false;
  }

  if (JSID_IS_SYMBOL(id)) {
    JS::RootedSymbol sym(cx, JSID_TO_SYMBOL(id));
    if (JS::GetSymbolCode(sym) == JS::SymbolCode::toPrimitive) {
      JS::RootedObject obj(
          cx, JS_GetFunctionObject(JS_NewFunction(cx, NPObjWrapper_toPrimitive,
                                                  1, 0, "Symbol.toPrimitive")));
      if (!obj) return false;
      vp.setObject(*obj);
      return true;
    }

    if (JS::GetSymbolCode(sym) == JS::SymbolCode::toStringTag) {
      JS::RootedString tag(cx, JS_NewStringCopyZ(cx, NPRUNTIME_JSCLASS_NAME));
      if (!tag) {
        return false;
      }

      vp.setString(tag);
      return true;
    }

    return js::BaseProxyHandler::get(cx, proxy, receiver, id, vp);
  }

  // Find out what plugin (NPP) is the owner of the object we're
  // manipulating, and make it own any JSObject wrappers created here.
  NPP npp = LookupNPP(npobj);
  if (!npp) {
    ThrowJSExceptionASCII(cx, "No NPP found for NPObject!");

    return false;
  }

  {
    bool resolved = false;
    JS::Rooted<JSObject *> method(cx);
    if (!NPObjWrapper_Resolve(cx, proxy, id, &resolved, &method)) return false;
    if (method) {
      vp.setObject(*method);
      return true;
    }
    if (!resolved) {
      // We don't have a property/method with this id. Forward to the prototype
      // chain.
      return js::BaseProxyHandler::get(cx, proxy, receiver, id, vp);
    }
  }

  PluginDestructionGuard pdg(npp);

  bool hasProperty, hasMethod;

  NPVariant npv;
  VOID_TO_NPVARIANT(npv);

  NPIdentifier identifier = JSIdToNPIdentifier(id);

  if (NPObjectIsOutOfProcessProxy(npobj)) {
    PluginScriptableObjectParent *actor =
        static_cast<ParentNPObject *>(npobj)->parent;

    // actor may be null if the plugin crashed.
    if (!actor) return false;

    bool success =
        actor->GetPropertyHelper(identifier, &hasProperty, &hasMethod, &npv);

    if (!ReportExceptionIfPending(cx)) {
      if (success) _releasevariantvalue(&npv);
      return false;
    }

    if (success) {
      // We return NPObject Member class here to support ambiguous members.
      if (hasProperty && hasMethod)
        return CreateNPObjectMember(npp, cx, proxy, npobj, id, &npv, vp);

      if (hasProperty) {
        vp.set(NPVariantToJSVal(npp, cx, &npv));
        _releasevariantvalue(&npv);

        if (!ReportExceptionIfPending(cx)) return false;
        return true;
      }
    }
    return js::BaseProxyHandler::get(cx, proxy, receiver, id, vp);
  }

  hasProperty = npobj->_class->hasProperty(npobj, identifier);
  if (!ReportExceptionIfPending(cx)) return false;

  hasMethod = npobj->_class->hasMethod(npobj, identifier);
  if (!ReportExceptionIfPending(cx)) return false;

  // We return NPObject Member class here to support ambiguous members.
  if (hasProperty && hasMethod)
    return CreateNPObjectMember(npp, cx, proxy, npobj, id, nullptr, vp);

  if (hasProperty) {
    if (npobj->_class->getProperty(npobj, identifier, &npv))
      vp.set(NPVariantToJSVal(npp, cx, &npv));

    _releasevariantvalue(&npv);

    if (!ReportExceptionIfPending(cx)) return false;
    return true;
  }

  return js::BaseProxyHandler::get(cx, proxy, receiver, id, vp);
}

static bool CallNPMethodInternal(JSContext *cx, JS::Handle<JSObject *> obj,
                                 unsigned argc, JS::Value *argv,
                                 JS::Value *rval, bool ctorCall) {
  NPObject *npobj = GetNPObject(cx, obj);

  if (!npobj || !npobj->_class) {
    ThrowJSExceptionASCII(cx, "Bad NPObject as private data!");

    return false;
  }

  // Find out what plugin (NPP) is the owner of the object we're
  // manipulating, and make it own any JSObject wrappers created here.
  NPP npp = LookupNPP(npobj);

  if (!npp) {
    ThrowJSExceptionASCII(cx, "Error finding NPP for NPObject!");

    return false;
  }

  PluginDestructionGuard pdg(npp);

  NPVariant npargs_buf[8];
  NPVariant *npargs = npargs_buf;

  if (argc > (sizeof(npargs_buf) / sizeof(NPVariant))) {
    // Our stack buffer isn't large enough to hold all arguments,
    // malloc a buffer.
    npargs = (NPVariant *)malloc(argc * sizeof(NPVariant));

    if (!npargs) {
      ThrowJSExceptionASCII(cx, "Out of memory!");

      return false;
    }
  }

  // Convert arguments
  uint32_t i;
  for (i = 0; i < argc; ++i) {
    if (!JSValToNPVariant(npp, cx, argv[i], npargs + i)) {
      ThrowJSExceptionASCII(cx, "Error converting jsvals to NPVariants!");

      if (npargs != npargs_buf) {
        free(npargs);
      }

      return false;
    }
  }

  NPVariant v;
  VOID_TO_NPVARIANT(v);

  JSObject *funobj = argv[-2].toObjectOrNull();
  bool ok;
  const char *msg = "Error calling method on NPObject!";

  if (ctorCall) {
    // construct a new NPObject based on the NPClass in npobj. Fail if
    // no construct method is available.

    if (NP_CLASS_STRUCT_VERSION_HAS_CTOR(npobj->_class) &&
        npobj->_class->construct) {
      ok = npobj->_class->construct(npobj, npargs, argc, &v);
    } else {
      ok = false;

      msg = "Attempt to construct object from class with no constructor.";
    }
  } else if (funobj != obj) {
    // A obj.function() style call is made, get the method name from
    // the function object.

    if (npobj->_class->invoke) {
      JSFunction *fun = ::JS_GetObjectFunction(funobj);
      JS::Rooted<JSString *> funId(cx, ::JS_GetFunctionId(fun));
      JSString *name = ::JS_AtomizeAndPinJSString(cx, funId);
      NPIdentifier id = StringToNPIdentifier(cx, name);

      ok = npobj->_class->invoke(npobj, id, npargs, argc, &v);
    } else {
      ok = false;

      msg = "Attempt to call a method on object with no invoke method.";
    }
  } else {
    if (npobj->_class->invokeDefault) {
      // obj is a callable object that is being called, no method name
      // available then. Invoke the default method.

      ok = npobj->_class->invokeDefault(npobj, npargs, argc, &v);
    } else {
      ok = false;

      msg =
          "Attempt to call a default method on object with no "
          "invokeDefault method.";
    }
  }

  // Release arguments.
  for (i = 0; i < argc; ++i) {
    _releasevariantvalue(npargs + i);
  }

  if (npargs != npargs_buf) {
    free(npargs);
  }

  if (!ok) {
    // ReportExceptionIfPending returns a return value, which is true
    // if no exception was thrown. In that case, throw our own.
    if (ReportExceptionIfPending(cx)) ThrowJSExceptionASCII(cx, msg);

    return false;
  }

  *rval = NPVariantToJSVal(npp, cx, &v);

  // *rval now owns the value, release our reference.
  _releasevariantvalue(&v);

  return ReportExceptionIfPending(cx);
}

static bool CallNPMethod(JSContext *cx, unsigned argc, JS::Value *vp) {
  JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
  if (!args.thisv().isObject()) {
    ThrowJSExceptionASCII(cx,
                          "plug-in method called on incompatible non-object");
    return false;
  }
  JS::Rooted<JSObject *> obj(cx, &args.thisv().toObject());
  return CallNPMethodInternal(cx, obj, args.length(), args.array(), vp, false);
}

bool NPObjWrapperProxyHandler::getOwnPropertyDescriptor(
    JSContext *cx, JS::Handle<JSObject *> proxy, JS::Handle<jsid> id,
    JS::MutableHandle<JS::PropertyDescriptor> desc) const {
  bool resolved = false;
  JS::Rooted<JSObject *> method(cx);
  if (!NPObjWrapper_Resolve(cx, proxy, id, &resolved, &method)) return false;
  if (!resolved) {
    // No such property.
    desc.object().set(nullptr);
    return true;
  }

  // This returns a descriptor with |null| JS value if this is a plugin
  // property (as opposed to a method). That should be fine, hopefully, as the
  // previous code had very inconsistent behavior in this case as well. The main
  // reason for returning a descriptor here is to make property enumeration work
  // correctly (it will call getOwnPropertyDescriptor to check enumerability).
  JS::Rooted<JS::Value> val(cx, JS::ObjectOrNullValue(method));
  desc.initFields(proxy, val, JSPROP_ENUMERATE, nullptr, nullptr);
  return true;
}

bool NPObjWrapperProxyHandler::ownPropertyKeys(
    JSContext *cx, JS::Handle<JSObject *> proxy,
    JS::AutoIdVector &properties) const {
  NPObject *npobj = GetNPObject(cx, proxy);
  if (!npobj || !npobj->_class) {
    ThrowJSExceptionASCII(cx, "Bad NPObject as private data!");
    return false;
  }

  PluginDestructionGuard pdg(LookupNPP(npobj));

  if (!NP_CLASS_STRUCT_VERSION_HAS_ENUM(npobj->_class) ||
      !npobj->_class->enumerate) {
    return true;
  }

  NPIdentifier *identifiers;
  uint32_t length;
  if (!npobj->_class->enumerate(npobj, &identifiers, &length)) {
    if (ReportExceptionIfPending(cx)) {
      // ReportExceptionIfPending returns a return value, which is true
      // if no exception was thrown. In that case, throw our own.
      ThrowJSExceptionASCII(cx,
                            "Error enumerating properties on scriptable "
                            "plugin object");
    }
    return false;
  }

  if (!properties.reserve(length)) return false;

  JS::Rooted<jsid> id(cx);
  for (uint32_t i = 0; i < length; i++) {
    id = NPIdentifierToJSId(identifiers[i]);
    properties.infallibleAppend(id);
  }

  free(identifiers);
  return true;
}

// This function is very similar to a resolve hook for native objects. Instead
// of defining properties on the object, it defines them on a resolvedProps
// object (a plain JS object that's never exposed to script) that's stored in
// the NPObjWrapper proxy's reserved slot. The behavior is as follows:
//
// - *resolvedp is set to true iff the plugin object has a property or method
//   (or both) with this id.
//
// - If the plugin object has a *property* with this id, the caller is
//   responsible for getting/setting its value. In this case we assign |null|
//   to resolvedProps[id] so we don't have to call hasProperty each time.
//
// - If the plugin object has a *method* with this id, we create a JSFunction to
//   call it and assign it to resolvedProps[id]. This function is also assigned
//   to the |method| outparam so callers can return it directly if we're doing a
//   |get|.
static bool NPObjWrapper_Resolve(JSContext *cx, JS::Handle<JSObject *> obj,
                                 JS::Handle<jsid> id, bool *resolvedp,
                                 JS::MutableHandle<JSObject *> method) {
  if (JSID_IS_SYMBOL(id)) return true;

  AUTO_PROFILER_LABEL("NPObjWrapper_Resolve", JS);

  NPObject *npobj = GetNPObject(cx, obj);

  if (!npobj || !npobj->_class || !npobj->_class->hasProperty ||
      !npobj->_class->hasMethod) {
    ThrowJSExceptionASCII(cx, "Bad NPObject as private data!");

    return false;
  }

  JS::Rooted<JSObject *> resolvedProps(cx,
                                       NPObjWrapper_GetResolvedProps(cx, obj));
  if (!resolvedProps) return false;
  JS::Rooted<JS::Value> res(cx);
  if (!JS_GetPropertyById(cx, resolvedProps, id, &res)) return false;
  if (res.isObjectOrNull()) {
    method.set(res.toObjectOrNull());
    *resolvedp = true;
    return true;
  }

  PluginDestructionGuard pdg(LookupNPP(npobj));

  NPIdentifier identifier = JSIdToNPIdentifier(id);

  bool hasProperty = npobj->_class->hasProperty(npobj, identifier);
  if (!ReportExceptionIfPending(cx)) return false;

  if (hasProperty) {
    if (!JS_SetPropertyById(cx, resolvedProps, id, JS::NullHandleValue))
      return false;
    *resolvedp = true;

    return true;
  }

  bool hasMethod = npobj->_class->hasMethod(npobj, identifier);
  if (!ReportExceptionIfPending(cx)) return false;

  if (hasMethod) {
    NS_ASSERTION(JSID_IS_STRING(id) || JSID_IS_INT(id),
                 "id must be either string or int!\n");

    JSFunction *fnc = ::JS_DefineFunctionById(
        cx, resolvedProps, id, CallNPMethod, 0, JSPROP_ENUMERATE);
    if (!fnc) return false;

    method.set(JS_GetFunctionObject(fnc));
    *resolvedp = true;
    return true;
  }

  // no property or method
  return true;
}

void NPObjWrapperProxyHandler::finalize(JSFreeOp *fop, JSObject *proxy) const {
  JS::AutoAssertGCCallback inCallback;

  NPObject *npobj = (NPObject *)js::GetProxyPrivate(proxy).toPrivate();
  if (npobj) {
    if (sNPObjWrappers) {
      // If the sNPObjWrappers map contains an entry that refers to this
      // wrapper, remove it.
      auto entry =
          static_cast<NPObjWrapperHashEntry *>(sNPObjWrappers->Search(npobj));
      if (entry && entry->mJSObj == proxy) {
        sNPObjWrappers->Remove(npobj);
      }
    }
  }

  if (!sDelayedReleases) sDelayedReleases = new nsTArray<NPObject *>;
  sDelayedReleases->AppendElement(npobj);
}

size_t NPObjWrapperProxyHandler::objectMoved(JSObject *obj,
                                             JSObject *old) const {
  // The wrapper JSObject has been moved, so we need to update the entry in the
  // sNPObjWrappers hash table, if present.

  if (!sNPObjWrappers) {
    return 0;
  }

  NPObject *npobj = (NPObject *)js::GetProxyPrivate(obj).toPrivate();
  if (!npobj) {
    return 0;
  }

  // Calling PLDHashTable::Search() will not result in GC.
  JS::AutoSuppressGCAnalysis nogc;

  auto entry =
      static_cast<NPObjWrapperHashEntry *>(sNPObjWrappers->Search(npobj));
  MOZ_ASSERT(entry && entry->mJSObj);
  MOZ_ASSERT(entry->mJSObj == old);
  entry->mJSObj = obj;
  return 0;
}

bool NPObjWrapperProxyHandler::call(JSContext *cx, JS::Handle<JSObject *> proxy,
                                    const JS::CallArgs &args) const {
  return CallNPMethodInternal(cx, proxy, args.length(), args.array(),
                              args.rval().address(), false);
}

bool NPObjWrapperProxyHandler::construct(JSContext *cx,
                                         JS::Handle<JSObject *> proxy,
                                         const JS::CallArgs &args) const {
  return CallNPMethodInternal(cx, proxy, args.length(), args.array(),
                              args.rval().address(), true);
}

static bool NPObjWrapper_toPrimitive(JSContext *cx, unsigned argc,
                                     JS::Value *vp) {
  // Plugins do not simply use the default OrdinaryToPrimitive behavior,
  // because that behavior involves calling toString or valueOf on objects
  // which weren't designed to accommodate this.  Usually this wouldn't be a
  // problem, because the absence of either property, or the presence of either
  // property with a value that isn't callable, will cause that property to
  // simply be ignored.  But there is a problem in one specific case: Java,
  // specifically java.lang.Integer.  The Integer class has static valueOf
  // methods, none of which are nullary, so the JS-reflected method will behave
  // poorly when called with no arguments.  We work around this problem by
  // giving plugins a [Symbol.toPrimitive]() method which uses only toString
  // and not valueOf.

  JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
  JS::RootedValue thisv(cx, args.thisv());
  if (thisv.isPrimitive()) return true;

  JS::RootedObject obj(cx, &thisv.toObject());
  JS::RootedValue v(cx);
  if (!JS_GetProperty(cx, obj, "toString", &v)) return false;
  if (v.isObject() && JS::IsCallable(&v.toObject())) {
    if (!JS_CallFunctionValue(cx, obj, v, JS::HandleValueArray::empty(),
                              args.rval()))
      return false;
    if (args.rval().isPrimitive()) return true;
  }

  JS_ReportErrorNumberASCII(cx, js::GetErrorMessage, nullptr,
                            JSMSG_CANT_CONVERT_TO, JS_GetClass(obj)->name,
                            "primitive type");
  return false;
}

bool nsNPObjWrapper::IsWrapper(JSObject *obj) {
  return js::GetObjectClass(obj) == &sNPObjWrapperProxyClass;
}

// An NPObject is going away, make sure we null out the JS object's
// private data in case this is an NPObject that came from a plugin
// and it's destroyed prematurely.

// static
void nsNPObjWrapper::OnDestroy(NPObject *npobj) {
  if (!npobj) {
    return;
  }

  if (npobj->_class == &nsJSObjWrapper::sJSObjWrapperNPClass) {
    // npobj is one of our own, no private data to clean up here.

    return;
  }

  if (!sNPObjWrappers) {
    // No hash yet (or any more), no used wrappers available.

    return;
  }

  auto entry =
      static_cast<NPObjWrapperHashEntry *>(sNPObjWrappers->Search(npobj));

  if (entry && entry->mJSObj) {
    // Found an NPObject wrapper, null out its JSObjects' private data.
    js::SetProxyPrivate(entry->mJSObj.unbarrieredGetPtr(),
                        JS::PrivateValue(nullptr));

    // Remove the npobj from the hash now that it went away.
    sNPObjWrappers->RawRemove(entry);

    // The finalize hook will call OnWrapperDestroyed().
  }
}

// Look up or create a JSObject that wraps the NPObject npobj. The return value
// is always in the compartment of the passed-in JSContext (it might be a CCW).

// static
JSObject *nsNPObjWrapper::GetNewOrUsed(NPP npp, JSContext *cx,
                                       NPObject *npobj) {
  if (!npobj) {
    NS_ERROR("Null NPObject passed to nsNPObjWrapper::GetNewOrUsed()!");

    return nullptr;
  }

  if (npobj->_class == &nsJSObjWrapper::sJSObjWrapperNPClass) {
    // npobj is one of our own, return its existing JSObject.

    JS::Rooted<JSObject *> obj(cx, ((nsJSObjWrapper *)npobj)->mJSObj);
    if (!JS_WrapObject(cx, &obj)) {
      return nullptr;
    }
    return obj;
  }

  if (!npp) {
    NS_ERROR("No npp passed to nsNPObjWrapper::GetNewOrUsed()!");

    return nullptr;
  }

  if (!sNPObjWrappers) {
    // No hash yet (or any more), initialize it.
    if (!CreateNPObjWrapperTable()) {
      return nullptr;
    }
  }

  auto entry = static_cast<NPObjWrapperHashEntry *>(
      sNPObjWrappers->Add(npobj, fallible));

  if (!entry) {
    // Out of memory
    JS_ReportOutOfMemory(cx);

    return nullptr;
  }

  if (entry->mJSObj) {
    // Found a NPObject wrapper. First check it is still alive.
    JSObject *obj = entry->mJSObj.unbarrieredGetPtr();
    if (js::gc::EdgeNeedsSweepUnbarriered(&obj)) {
      // The object is dead (finalization will happen at a later time). By the
      // time we leave this function, this entry will either be updated with a
      // new wrapper or removed if that fails. Clear it anyway to make sure
      // nothing touches the dead object.
      entry->mJSObj = nullptr;
    } else {
      // It may not be in the same compartment as cx, so we need to wrap it
      // before returning it.
      JS::Rooted<JSObject *> obj(cx, entry->mJSObj);
      if (!JS_WrapObject(cx, &obj)) {
        return nullptr;
      }
      return obj;
    }
  }

  entry->mNPObj = npobj;
  entry->mNpp = npp;

  uint32_t generation = sNPObjWrappers->Generation();

  // No existing JSObject, create one.

  JS::RootedValue priv(cx, JS::PrivateValue(nullptr));
  js::ProxyOptions options;
  options.setClass(&sNPObjWrapperProxyClass);
  JS::Rooted<JSObject *> obj(
      cx, js::NewProxyObject(cx, &NPObjWrapperProxyHandler::singleton, priv,
                             nullptr, options));

  if (generation != sNPObjWrappers->Generation()) {
    // Reload entry if the JS_NewObject call caused a GC and reallocated
    // the table (see bug 445229). This is guaranteed to succeed.

    entry = static_cast<NPObjWrapperHashEntry *>(sNPObjWrappers->Search(npobj));
    NS_ASSERTION(entry, "Hashtable didn't find what we just added?");
  }

  if (!obj) {
    // OOM? Remove the stale entry from the hash.

    sNPObjWrappers->RawRemove(entry);

    return nullptr;
  }

  OnWrapperCreated();

  entry->mJSObj = obj;

  js::SetProxyPrivate(obj, JS::PrivateValue(npobj));

  // The new JSObject now holds on to npobj
  _retainobject(npobj);

  return obj;
}

// static
void nsJSNPRuntime::OnPluginDestroy(NPP npp) {
  if (sJSObjWrappersAccessible) {
    // Prevent modification of sJSObjWrappers table if we go reentrant.
    sJSObjWrappersAccessible = false;

    for (auto iter = sJSObjWrappers->modIter(); !iter.done(); iter.next()) {
      nsJSObjWrapper *npobj = iter.get().value();
      MOZ_ASSERT(npobj->_class == &nsJSObjWrapper::sJSObjWrapperNPClass);
      if (npobj->mNpp == npp) {
        if (npobj->_class && npobj->_class->invalidate) {
          npobj->_class->invalidate(npobj);
        }

        _releaseobject(npobj);

        iter.remove();
      }
    }

    sJSObjWrappersAccessible = true;
  }

  if (sNPObjWrappers) {
    for (auto i = sNPObjWrappers->Iter(); !i.Done(); i.Next()) {
      auto entry = static_cast<NPObjWrapperHashEntry *>(i.Get());

      if (entry->mNpp == npp) {
        // HACK: temporarily hide the table we're enumerating so that
        // invalidate() and deallocate() don't touch it.
        PLDHashTable *tmp = sNPObjWrappers;
        sNPObjWrappers = nullptr;

        NPObject *npobj = entry->mNPObj;

        if (npobj->_class && npobj->_class->invalidate) {
          npobj->_class->invalidate(npobj);
        }

#ifdef NS_BUILD_REFCNT_LOGGING
        {
          int32_t refCnt = npobj->referenceCount;
          while (refCnt) {
            --refCnt;
            NS_LOG_RELEASE(npobj, refCnt, "BrowserNPObject");
          }
        }
#endif

        // Force deallocation of plugin objects since the plugin they came
        // from is being torn down.
        if (npobj->_class && npobj->_class->deallocate) {
          npobj->_class->deallocate(npobj);
        } else {
          free(npobj);
        }

        js::SetProxyPrivate(entry->mJSObj.unbarrieredGetPtr(),
                            JS::PrivateValue(nullptr));

        sNPObjWrappers = tmp;

        if (sDelayedReleases && sDelayedReleases->RemoveElement(npobj)) {
          OnWrapperDestroyed();
        }

        i.Remove();
      }
    }
  }
}

// static
void nsJSNPRuntime::OnPluginDestroyPending(NPP npp) {
  if (sJSObjWrappersAccessible) {
    // Prevent modification of sJSObjWrappers table if we go reentrant.
    sJSObjWrappersAccessible = false;
    for (auto iter = sJSObjWrappers->iter(); !iter.done(); iter.next()) {
      nsJSObjWrapper *npobj = iter.get().value();
      MOZ_ASSERT(npobj->_class == &nsJSObjWrapper::sJSObjWrapperNPClass);
      if (npobj->mNpp == npp) {
        npobj->mDestroyPending = true;
      }
    }
    sJSObjWrappersAccessible = true;
  }
}

// Find the NPP for a NPObject.
static NPP LookupNPP(NPObject *npobj) {
  if (npobj->_class == &nsJSObjWrapper::sJSObjWrapperNPClass) {
    nsJSObjWrapper *o = static_cast<nsJSObjWrapper *>(npobj);
    return o->mNpp;
  }

  auto entry = static_cast<NPObjWrapperHashEntry *>(
      sNPObjWrappers->Add(npobj, fallible));

  if (!entry) {
    return nullptr;
  }

  NS_ASSERTION(entry->mNpp, "Live NPObject entry w/o an NPP!");

  return entry->mNpp;
}

static bool CreateNPObjectMember(NPP npp, JSContext *cx,
                                 JS::Handle<JSObject *> aObj, NPObject *npobj,
                                 JS::Handle<jsid> id,
                                 NPVariant *getPropertyResult,
                                 JS::MutableHandle<JS::Value> vp) {
  if (!npobj || !npobj->_class || !npobj->_class->getProperty ||
      !npobj->_class->invoke) {
    ThrowJSExceptionASCII(cx, "Bad NPObject");

    return false;
  }

  NPObjectMemberPrivate *memberPrivate =
      (NPObjectMemberPrivate *)malloc(sizeof(NPObjectMemberPrivate));
  if (!memberPrivate) return false;

  // Make sure to clear all members in case something fails here
  // during initialization.
  memset(memberPrivate, 0, sizeof(NPObjectMemberPrivate));

  JS::Rooted<JSObject *> obj(cx, aObj);

  JS::Rooted<JSObject *> memobj(cx, ::JS_NewObject(cx, &sNPObjectMemberClass));
  if (!memobj) {
    free(memberPrivate);
    return false;
  }

  vp.setObject(*memobj);

  ::JS_SetPrivate(memobj, (void *)memberPrivate);

  NPIdentifier identifier = JSIdToNPIdentifier(id);

  JS::Rooted<JS::Value> fieldValue(cx);
  NPVariant npv;

  if (getPropertyResult) {
    // Plugin has already handed us the value we want here.
    npv = *getPropertyResult;
  } else {
    VOID_TO_NPVARIANT(npv);

    NPBool hasProperty = npobj->_class->getProperty(npobj, identifier, &npv);
    if (!ReportExceptionIfPending(cx) || !hasProperty) {
      return false;
    }
  }

  fieldValue = NPVariantToJSVal(npp, cx, &npv);

  // npobjWrapper is the JSObject through which we make sure we don't
  // outlive the underlying NPObject, so make sure it points to the
  // real JSObject wrapper for the NPObject.
  obj = GetNPObjectWrapper(cx, obj);

  memberPrivate->npobjWrapper = obj;

  memberPrivate->fieldValue = fieldValue;
  memberPrivate->methodName = id;
  memberPrivate->npp = npp;

  // Finally, define the Symbol.toPrimitive property on |memobj|.

  JS::Rooted<jsid> toPrimitiveId(cx);
  toPrimitiveId =
      SYMBOL_TO_JSID(JS::GetWellKnownSymbol(cx, JS::SymbolCode::toPrimitive));

  JSFunction *fun = JS_NewFunction(cx, NPObjectMember_toPrimitive, 1, 0,
                                   "Symbol.toPrimitive");
  if (!fun) return false;

  JS::Rooted<JSObject *> funObj(cx, JS_GetFunctionObject(fun));
  if (!JS_DefinePropertyById(cx, memobj, toPrimitiveId, funObj, 0))
    return false;

  return true;
}

static void NPObjectMember_Finalize(JSFreeOp *fop, JSObject *obj) {
  NPObjectMemberPrivate *memberPrivate;

  memberPrivate = (NPObjectMemberPrivate *)::JS_GetPrivate(obj);
  if (!memberPrivate) return;

  free(memberPrivate);
}

static bool NPObjectMember_Call(JSContext *cx, unsigned argc, JS::Value *vp) {
  JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
  JS::Rooted<JSObject *> memobj(cx, &args.callee());
  NS_ENSURE_TRUE(memobj, false);

  NPObjectMemberPrivate *memberPrivate =
      (NPObjectMemberPrivate *)::JS_GetInstancePrivate(
          cx, memobj, &sNPObjectMemberClass, &args);
  if (!memberPrivate || !memberPrivate->npobjWrapper) return false;

  JS::Rooted<JSObject *> objWrapper(cx, memberPrivate->npobjWrapper);
  NPObject *npobj = GetNPObject(cx, objWrapper);
  if (!npobj) {
    ThrowJSExceptionASCII(cx, "Call on invalid member object");

    return false;
  }

  NPVariant npargs_buf[8];
  NPVariant *npargs = npargs_buf;

  if (args.length() > (sizeof(npargs_buf) / sizeof(NPVariant))) {
    // Our stack buffer isn't large enough to hold all arguments,
    // malloc a buffer.
    npargs = (NPVariant *)malloc(args.length() * sizeof(NPVariant));

    if (!npargs) {
      ThrowJSExceptionASCII(cx, "Out of memory!");

      return false;
    }
  }

  // Convert arguments
  for (uint32_t i = 0; i < args.length(); ++i) {
    if (!JSValToNPVariant(memberPrivate->npp, cx, args[i], npargs + i)) {
      ThrowJSExceptionASCII(cx, "Error converting jsvals to NPVariants!");

      if (npargs != npargs_buf) {
        free(npargs);
      }

      return false;
    }
  }

  NPVariant npv;
  bool ok = npobj->_class->invoke(npobj,
                                  JSIdToNPIdentifier(memberPrivate->methodName),
                                  npargs, args.length(), &npv);

  // Release arguments.
  for (uint32_t i = 0; i < args.length(); ++i) {
    _releasevariantvalue(npargs + i);
  }

  if (npargs != npargs_buf) {
    free(npargs);
  }

  if (!ok) {
    // ReportExceptionIfPending returns a return value, which is true
    // if no exception was thrown. In that case, throw our own.
    if (ReportExceptionIfPending(cx))
      ThrowJSExceptionASCII(cx, "Error calling method on NPObject!");

    return false;
  }

  args.rval().set(NPVariantToJSVal(memberPrivate->npp, cx, &npv));

  // *vp now owns the value, release our reference.
  _releasevariantvalue(&npv);

  return ReportExceptionIfPending(cx);
}

static void NPObjectMember_Trace(JSTracer *trc, JSObject *obj) {
  NPObjectMemberPrivate *memberPrivate =
      (NPObjectMemberPrivate *)::JS_GetPrivate(obj);
  if (!memberPrivate) return;

  // Our NPIdentifier is not always interned, so we must trace it.
  JS::TraceEdge(trc, &memberPrivate->methodName,
                "NPObjectMemberPrivate.methodName");

  JS::TraceEdge(trc, &memberPrivate->fieldValue,
                "NPObject Member => fieldValue");

  // There's no strong reference from our private data to the
  // NPObject, so make sure to mark the NPObject wrapper to keep the
  // NPObject alive as long as this NPObjectMember is alive.
  JS::TraceEdge(trc, &memberPrivate->npobjWrapper,
                "NPObject Member => npobjWrapper");
}

static bool NPObjectMember_toPrimitive(JSContext *cx, unsigned argc,
                                       JS::Value *vp) {
  JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
  JS::RootedValue thisv(cx, args.thisv());
  if (thisv.isPrimitive()) {
    args.rval().set(thisv);
    return true;
  }

  JS::RootedObject obj(cx, &thisv.toObject());
  NPObjectMemberPrivate *memberPrivate =
      (NPObjectMemberPrivate *)::JS_GetInstancePrivate(
          cx, obj, &sNPObjectMemberClass, &args);
  if (!memberPrivate) return false;

  JSType hint;
  if (!JS::GetFirstArgumentAsTypeHint(cx, args, &hint)) return false;

  args.rval().set(memberPrivate->fieldValue);
  if (args.rval().isObject()) {
    JS::Rooted<JSObject *> objVal(cx, &args.rval().toObject());
    return JS::ToPrimitive(cx, objVal, hint, args.rval());
  }
  return true;
}