1 files changed, 92 insertions, 0 deletions
diff --git a/dom/base/MozQueryInterface.cpp b/dom/base/MozQueryInterface.cpp
new file mode 100644
index 0000000000..032b827b3b
--- /dev/null
+++ b/dom/base/MozQueryInterface.cpp
@@ -0,0 +1,92 @@
+/* -*- 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