1 files changed, 120 insertions, 0 deletions
diff --git a/dom/locks/LockRequestChild.cpp b/dom/locks/LockRequestChild.cpp
new file mode 100644
index 0000000000..51731c5eed
--- /dev/null
+++ b/dom/locks/LockRequestChild.cpp
@@ -0,0 +1,120 @@
+/* -*- 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 "LockManagerChild.h"
+#include "LockRequestChild.h"
+
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/WorkerPrivate.h"
+
+namespace mozilla::dom::locks {
+
+using IPCResult = mozilla::ipc::IPCResult;
+
+NS_IMPL_ISUPPORTS(LockRequestChild, nsISupports)
+
+MOZ_CAN_RUN_SCRIPT static void RunCallbackAndSettlePromise(
+    LockGrantedCallback& aCallback, mozilla::dom::Lock* lock,
+    Promise& aPromise) {
+  ErrorResult rv;
+  if (RefPtr<Promise> result = aCallback.Call(
+          lock, rv, nullptr, CallbackObject::eRethrowExceptions)) {
+    aPromise.MaybeResolve(result);
+  } else if (rv.Failed() && !rv.IsUncatchableException()) {
+    aPromise.MaybeReject(std::move(rv));
+    return;
+  } else {
+    aPromise.MaybeResolveWithUndefined();
+  }
+  // This is required even with no failure. IgnoredErrorResult is not an option
+  // since MaybeReject does not accept it.
+  rv.WouldReportJSException();
+  if (NS_WARN_IF(rv.IsUncatchableException())) {
+    rv.SuppressException();  // XXX: Why does this happen anyway?
+  }
+  MOZ_ASSERT(!rv.Failed());
+}
+
+LockRequestChild::LockRequestChild(
+    const LockRequest& aRequest,
+    const Optional<OwningNonNull<AbortSignal>>& aSignal)
+    : mRequest(aRequest) {
+  if (aSignal.WasPassed()) {
+    Follow(&aSignal.Value());
+  }
+}
+
+void LockRequestChild::MaybeSetWorkerRef() {
+  if (!NS_IsMainThread()) {
+    mWorkerRef = StrongWorkerRef::Create(
+        GetCurrentThreadWorkerPrivate(), "LockManager",
+        [self = RefPtr(this)]() { self->mWorkerRef = nullptr; });
+  }
+}
+
+void LockRequestChild::ActorDestroy(ActorDestroyReason aReason) {
+  CastedManager()->NotifyRequestDestroy();
+}
+
+IPCResult LockRequestChild::RecvResolve(const LockMode& aLockMode,
+                                        bool aIsAvailable) {
+  Unfollow();
+
+  RefPtr<Lock> lock;
+  RefPtr<Promise> promise;
+  if (aIsAvailable) {
+    IgnoredErrorResult err;
+    lock = new Lock(CastedManager()->GetParentObject(), this, mRequest.mName,
+                    aLockMode, mRequest.mPromise, err);
+    if (MOZ_UNLIKELY(err.Failed())) {
+      mRequest.mPromise->MaybeRejectWithUnknownError(
+          "Failed to allocate a lock");
+      return IPC_OK();
+    }
+    lock->GetWaitingPromise().AppendNativeHandler(lock);
+    promise = &lock->GetWaitingPromise();
+  } else {
+    // We are in `ifAvailable: true` mode and the lock is not available.
+    // There is no waitingPromise since there is no lock, so settle the promise
+    // from the request instead.
+    // This matches "If ifAvailable is true and request is not grantable" step.
+    promise = mRequest.mPromise;
+  }
+
+  // XXX(krosylight): MOZ_KnownLive shouldn't be needed here, mRequest is const
+  RunCallbackAndSettlePromise(MOZ_KnownLive(*mRequest.mCallback), lock,
+                              *promise);
+  return IPC_OK();
+}
+
+IPCResult LockRequestChild::Recv__delete__(bool aAborted) {
+  MOZ_ASSERT(aAborted, "__delete__ is currently only for abort");
+  Unfollow();
+  mRequest.mPromise->MaybeRejectWithAbortError("The lock request is aborted");
+  return IPC_OK();
+}
+
+void LockRequestChild::RunAbortAlgorithm() {
+  AutoJSAPI jsapi;
+  if (NS_WARN_IF(
+          !jsapi.Init(static_cast<AbortSignal*>(Signal())->GetOwnerGlobal()))) {
+    mRequest.mPromise->MaybeRejectWithAbortError("The lock request is aborted");
+  } else {
+    JSContext* cx = jsapi.cx();
+    JS::Rooted<JS::Value> reason(cx);
+    Signal()->GetReason(cx, &reason);
+    mRequest.mPromise->MaybeReject(reason);
+  }
+
+  Unfollow();
+  Send__delete__(this, true);
+}
+
+inline LockManagerChild* LockRequestChild::CastedManager() const {
+  return static_cast<LockManagerChild*>(Manager());
+};
+
+}  // namespace mozilla::dom::locks