1 files changed, 225 insertions, 0 deletions
diff --git a/dom/ipc/jsactor/JSActorManager.cpp b/dom/ipc/jsactor/JSActorManager.cpp
new file mode 100644
index 0000000000..fda2cf7efc
--- /dev/null
+++ b/dom/ipc/jsactor/JSActorManager.cpp
@@ -0,0 +1,225 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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 "mozilla/dom/JSActorManager.h"
+#include "mozilla/dom/JSActorService.h"
+#include "mozilla/dom/PWindowGlobal.h"
+#include "mozilla/ipc/ProtocolUtils.h"
+#include "mozilla/ScopeExit.h"
+#include "mozJSComponentLoader.h"
+#include "jsapi.h"
+#include "nsContentUtils.h"
+
+namespace mozilla::dom {
+
+already_AddRefed<JSActor> JSActorManager::GetActor(JSContext* aCx,
+                                                   const nsACString& aName,
+                                                   ErrorResult& aRv) {
+  MOZ_ASSERT(nsContentUtils::IsSafeToRunScript());
+
+  // If our connection has been closed, return an error.
+  mozilla::ipc::IProtocol* nativeActor = AsNativeActor();
+  if (!nativeActor->CanSend()) {
+    aRv.ThrowInvalidStateError(nsPrintfCString(
+        "Cannot get actor '%s'. Native '%s' actor is destroyed.",
+        PromiseFlatCString(aName).get(), nativeActor->GetProtocolName()));
+    return nullptr;
+  }
+
+  // Check if this actor has already been created, and return it if it has.
+  if (RefPtr<JSActor> actor = mJSActors.Get(aName)) {
+    return actor.forget();
+  }
+
+  RefPtr<JSActorService> actorSvc = JSActorService::GetSingleton();
+  if (!actorSvc) {
+    aRv.ThrowInvalidStateError("JSActorService hasn't been initialized");
+    return nullptr;
+  }
+
+  // Check if this actor satisfies the requirements of the protocol
+  // corresponding to `aName`, and get the module which implements it.
+  RefPtr<JSActorProtocol> protocol =
+      MatchingJSActorProtocol(actorSvc, aName, aRv);
+  if (!protocol) {
+    return nullptr;
+  }
+
+  bool isParent = nativeActor->GetSide() == mozilla::ipc::ParentSide;
+  auto& side = isParent ? protocol->Parent() : protocol->Child();
+
+  // We're about to construct the actor, so make sure we're in the JSM realm
+  // while importing etc.
+  JSAutoRealm ar(aCx, xpc::PrivilegedJunkScope());
+
+  // Load the module using mozJSComponentLoader.
+  RefPtr<mozJSComponentLoader> loader = mozJSComponentLoader::Get();
+  MOZ_ASSERT(loader);
+
+  // If a module URI was provided, use it to construct an instance of the actor.
+  JS::RootedObject actorObj(aCx);
+  if (side.mModuleURI) {
+    JS::RootedObject global(aCx);
+    JS::RootedObject exports(aCx);
+    aRv = loader->Import(aCx, side.mModuleURI.ref(), &global, &exports);
+    if (aRv.Failed()) {
+      return nullptr;
+    }
+    MOZ_ASSERT(exports, "null exports!");
+
+    // Load the specific property from our module.
+    JS::RootedValue ctor(aCx);
+    nsAutoCString ctorName(aName);
+    ctorName.Append(isParent ? "Parent"_ns : "Child"_ns);
+    if (!JS_GetProperty(aCx, exports, ctorName.get(), &ctor)) {
+      aRv.NoteJSContextException(aCx);
+      return nullptr;
+    }
+
+    if (NS_WARN_IF(!ctor.isObject())) {
+      aRv.ThrowNotFoundError(nsPrintfCString(
+          "Could not find actor constructor '%s'", ctorName.get()));
+      return nullptr;
+    }
+
+    // Invoke the constructor loaded from the module.
+    if (!JS::Construct(aCx, ctor, JS::HandleValueArray::empty(), &actorObj)) {
+      aRv.NoteJSContextException(aCx);
+      return nullptr;
+    }
+  }
+
+  // Initialize our newly-constructed actor, and return it.
+  RefPtr<JSActor> actor = InitJSActor(actorObj, aName, aRv);
+  if (aRv.Failed()) {
+    return nullptr;
+  }
+  mJSActors.Put(aName, RefPtr{actor});
+  return actor.forget();
+}
+
+#define CHILD_DIAGNOSTIC_ASSERT(test, msg) \
+  do {                                     \
+    if (XRE_IsParentProcess()) {           \
+      MOZ_ASSERT(test, msg);               \
+    } else {                               \
+      MOZ_DIAGNOSTIC_ASSERT(test, msg);    \
+    }                                      \
+  } while (0)
+
+void JSActorManager::ReceiveRawMessage(
+    const JSActorMessageMeta& aMetadata,
+    Maybe<ipc::StructuredCloneData>&& aData,
+    Maybe<ipc::StructuredCloneData>&& aStack) {
+  MOZ_ASSERT(nsContentUtils::IsSafeToRunScript());
+
+  CrashReporter::AutoAnnotateCrashReport autoActorName(
+      CrashReporter::Annotation::JSActorName, aMetadata.actorName());
+  CrashReporter::AutoAnnotateCrashReport autoMessageName(
+      CrashReporter::Annotation::JSActorMessage,
+      NS_LossyConvertUTF16toASCII(aMetadata.messageName()));
+
+  // We're going to be running JS. Enter the privileged junk realm so we can set
+  // up our JS state correctly.
+  AutoEntryScript aes(xpc::PrivilegedJunkScope(), "JSActor message handler");
+  JSContext* cx = aes.cx();
+
+  // Ensure any errors reported to `error` are set on the scope, so they're
+  // reported.
+  ErrorResult error;
+  auto autoSetException =
+      MakeScopeExit([&] { Unused << error.MaybeSetPendingException(cx); });
+
+  // If an async stack was provided, set up our async stack state.
+  JS::Rooted<JSObject*> stack(cx);
+  Maybe<JS::AutoSetAsyncStackForNewCalls> stackSetter;
+  {
+    JS::Rooted<JS::Value> stackVal(cx);
+    if (aStack) {
+      aStack->Read(cx, &stackVal, error);
+      if (error.Failed()) {
+        error.SuppressException();
+        JS_ClearPendingException(cx);
+        stackVal.setUndefined();
+      }
+    }
+
+    if (stackVal.isObject()) {
+      stack = &stackVal.toObject();
+      if (!js::IsSavedFrame(stack)) {
+        CHILD_DIAGNOSTIC_ASSERT(false, "Stack must be a SavedFrame object");
+        error.ThrowDataError("Actor async stack must be a SavedFrame object");
+        return;
+      }
+      stackSetter.emplace(cx, stack, "JSActor query");
+    }
+  }
+
+  RefPtr<JSActor> actor = GetActor(cx, aMetadata.actorName(), error);
+  if (error.Failed()) {
+    return;
+  }
+
+  JS::Rooted<JS::Value> data(cx);
+  if (aData) {
+    aData->Read(cx, &data, error);
+    if (error.Failed()) {
+      CHILD_DIAGNOSTIC_ASSERT(false, "Should not receive non-decodable data");
+      return;
+    }
+  }
+
+  switch (aMetadata.kind()) {
+    case JSActorMessageKind::QueryResolve:
+    case JSActorMessageKind::QueryReject:
+      actor->ReceiveQueryReply(cx, aMetadata, data, error);
+      break;
+
+    case JSActorMessageKind::Message:
+      actor->ReceiveMessage(cx, aMetadata, data, error);
+      break;
+
+    case JSActorMessageKind::Query:
+      actor->ReceiveQuery(cx, aMetadata, data, error);
+      break;
+
+    default:
+      MOZ_ASSERT_UNREACHABLE();
+  }
+}
+
+void JSActorManager::JSActorWillDestroy() {
+  for (auto& entry : mJSActors) {
+    entry.GetData()->StartDestroy();
+  }
+}
+
+void JSActorManager::JSActorDidDestroy() {
+  MOZ_ASSERT(nsContentUtils::IsSafeToRunScript());
+  CrashReporter::AutoAnnotateCrashReport autoMessageName(
+      CrashReporter::Annotation::JSActorMessage, "<DidDestroy>"_ns);
+
+  // Swap the table with `mJSActors` so that we don't invalidate it while
+  // iterating.
+  nsRefPtrHashtable<nsCStringHashKey, JSActor> actors;
+  mJSActors.SwapElements(actors);
+  for (auto& entry : actors) {
+    CrashReporter::AutoAnnotateCrashReport autoActorName(
+        CrashReporter::Annotation::JSActorName, entry.GetData()->Name());
+    entry.GetData()->AfterDestroy();
+  }
+}
+
+void JSActorManager::JSActorUnregister(const nsACString& aName) {
+  MOZ_ASSERT(nsContentUtils::IsSafeToRunScript());
+
+  RefPtr<JSActor> actor;
+  if (mJSActors.Remove(aName, getter_AddRefs(actor))) {
+    actor->AfterDestroy();
+  }
+}
+
+}  // namespace mozilla::dom