gecko-dev/dom/base/MozQueryInterface.cpp

93 lines
2.7 KiB
C++

/* -*- Mode: C++; tab-width: 8; 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 "ChromeUtils.h"
#include "MozQueryInterface.h"
#include "xptinfo.h"
#include <string.h>
#include "jsapi.h"
#include "mozilla/ErrorResult.h"
#include "xpcpublic.h"
namespace mozilla::dom {
constexpr size_t IID_SIZE = sizeof(nsIID);
static_assert(
IID_SIZE == 16,
"Size of nsID struct changed. Please ensure this code is still valid.");
static int CompareIIDs(const nsIID& aA, const nsIID& aB) {
return memcmp((void*)&aA.m0, (void*)&aB.m0, IID_SIZE);
}
/* static */
UniquePtr<MozQueryInterface> ChromeUtils::GenerateQI(
const GlobalObject& aGlobal, const Sequence<JS::Value>& aInterfaces) {
JSContext* cx = aGlobal.Context();
nsTArray<nsIID> ifaces;
JS::Rooted<JS::Value> iface(cx);
for (uint32_t idx = 0; idx < aInterfaces.Length(); ++idx) {
iface = aInterfaces[idx];
// Handle ID objects
if (Maybe<nsID> id = xpc::JSValue2ID(cx, iface)) {
ifaces.AppendElement(*id);
continue;
}
// Accept string valued names
if (iface.isString()) {
JS::UniqueChars name = JS_EncodeStringToLatin1(cx, iface.toString());
const nsXPTInterfaceInfo* iinfo = nsXPTInterfaceInfo::ByName(name.get());
if (iinfo) {
ifaces.AppendElement(iinfo->IID());
continue;
}
}
// NOTE: We ignore unknown interfaces here because in some cases we try to
// pass them in to support multiple platforms.
}
MOZ_ASSERT(!ifaces.Contains(NS_GET_IID(nsISupports), CompareIIDs));
ifaces.AppendElement(NS_GET_IID(nsISupports));
ifaces.Sort(CompareIIDs);
return MakeUnique<MozQueryInterface>(std::move(ifaces));
}
bool MozQueryInterface::QueriesTo(const nsIID& aIID) const {
return mInterfaces.ContainsSorted(aIID, CompareIIDs);
}
void MozQueryInterface::LegacyCall(JSContext* cx, JS::Handle<JS::Value> thisv,
JS::Handle<JS::Value> aIID,
JS::MutableHandle<JS::Value> aResult,
ErrorResult& aRv) const {
Maybe<nsID> id = xpc::JSValue2ID(cx, aIID);
if (id && QueriesTo(*id)) {
aResult.set(thisv);
} else {
aRv.Throw(NS_ERROR_NO_INTERFACE);
}
}
bool MozQueryInterface::WrapObject(JSContext* aCx,
JS::Handle<JSObject*> aGivenProto,
JS::MutableHandle<JSObject*> aReflector) {
return MozQueryInterface_Binding::Wrap(aCx, this, aGivenProto, aReflector);
}
} // namespace mozilla::dom