1 files changed, 233 insertions, 0 deletions
diff --git a/dom/messagechannel/MessagePort.h b/dom/messagechannel/MessagePort.h
new file mode 100644
index 0000000000..b0365e6b81
--- /dev/null
+++ b/dom/messagechannel/MessagePort.h
@@ -0,0 +1,233 @@
+/* -*- 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/. */
+
+#ifndef mozilla_dom_MessagePort_h
+#define mozilla_dom_MessagePort_h
+
+#include "mozilla/Attributes.h"
+#include "mozilla/DOMEventTargetHelper.h"
+#include "mozilla/dom/DOMTypes.h"
+#include "mozilla/UniquePtr.h"
+#include "nsTArray.h"
+
+#ifdef XP_WIN
+#  undef PostMessage
+#endif
+
+class nsIGlobalObject;
+
+namespace mozilla::dom {
+
+class MessageData;
+class MessagePortChild;
+class PostMessageRunnable;
+class RefMessageBodyService;
+class SharedMessageBody;
+class StrongWorkerRef;
+struct StructuredSerializeOptions;
+
+// A class to hold a MessagePortIdentifier from
+// MessagePort::CloneAndDistentangle() and close if neither passed to
+// MessagePort::Create() nor release()ed to send via IPC.
+// When the `neutered` field of the MessagePortIdentifier is false, a close is
+// required.
+// This does not derive from MessagePortIdentifier because
+// MessagePortIdentifier is final and because use of UniqueMessagePortId as a
+// MessagePortIdentifier is intentionally prevented without release of
+// ownership.
+class UniqueMessagePortId final {
+ public:
+  UniqueMessagePortId() { mIdentifier.neutered() = true; }
+  explicit UniqueMessagePortId(const MessagePortIdentifier& aIdentifier)
+      : mIdentifier(aIdentifier) {}
+  UniqueMessagePortId(UniqueMessagePortId&& aOther) noexcept
+      : mIdentifier(aOther.mIdentifier) {
+    aOther.mIdentifier.neutered() = true;
+  }
+  ~UniqueMessagePortId() { ForceClose(); };
+  void ForceClose();
+
+  [[nodiscard]] MessagePortIdentifier release() {
+    MessagePortIdentifier id = mIdentifier;
+    mIdentifier.neutered() = true;
+    return id;
+  }
+  // const member accessors are not required because a const
+  // UniqueMessagePortId is not useful.
+  nsID& uuid() { return mIdentifier.uuid(); }
+  nsID& destinationUuid() { return mIdentifier.destinationUuid(); }
+  uint32_t& sequenceId() { return mIdentifier.sequenceId(); }
+  bool& neutered() { return mIdentifier.neutered(); }
+
+  UniqueMessagePortId(const UniqueMessagePortId& aOther) = delete;
+  void operator=(const UniqueMessagePortId& aOther) = delete;
+
+ private:
+  MessagePortIdentifier mIdentifier;
+};
+
+class MessagePort final : public DOMEventTargetHelper {
+  friend class PostMessageRunnable;
+
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(MessagePort, DOMEventTargetHelper)
+
+  static already_AddRefed<MessagePort> Create(nsIGlobalObject* aGlobal,
+                                              const nsID& aUUID,
+                                              const nsID& aDestinationUUID,
+                                              ErrorResult& aRv);
+
+  static already_AddRefed<MessagePort> Create(nsIGlobalObject* aGlobal,
+                                              UniqueMessagePortId& aIdentifier,
+                                              ErrorResult& aRv);
+
+  // For IPC.
+  static void ForceClose(const MessagePortIdentifier& aIdentifier);
+
+  virtual JSObject* WrapObject(JSContext* aCx,
+                               JS::Handle<JSObject*> aGivenProto) override;
+
+  void PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
+                   const Sequence<JSObject*>& aTransferable, ErrorResult& aRv);
+
+  void PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
+                   const StructuredSerializeOptions& aOptions,
+                   ErrorResult& aRv);
+
+  void Start();
+
+  void Close();
+
+  EventHandlerNonNull* GetOnmessage();
+
+  void SetOnmessage(EventHandlerNonNull* aCallback);
+
+  IMPL_EVENT_HANDLER(messageerror)
+
+  // Non WebIDL methods
+
+  void UnshippedEntangle(MessagePort* aEntangledPort);
+
+  bool CanBeCloned() const { return !mHasBeenTransferredOrClosed; }
+
+  void CloneAndDisentangle(UniqueMessagePortId& aIdentifier);
+
+  void CloseForced();
+
+  // These methods are useful for MessagePortChild
+
+  void Entangled(nsTArray<MessageData>& aMessages);
+  void MessagesReceived(nsTArray<MessageData>& aMessages);
+  void StopSendingDataConfirmed();
+  void Closed();
+
+ private:
+  enum State {
+    // When a port is created by a MessageChannel it is entangled with the
+    // other. They both run on the same thread, same event loop and the
+    // messages are added to the queues without using PBackground actors.
+    // When one of the port is shipped, the state is changed to
+    // StateEntangling.
+    eStateUnshippedEntangled,
+
+    // If the port is closed or cloned when we are in this state, we go in one
+    // of the following 2 steps. EntanglingForClose or ForDisentangle.
+    eStateEntangling,
+
+    // We are not fully entangled yet but are already disentangled.
+    eStateEntanglingForDisentangle,
+
+    // We are not fully entangled yet but are already closed.
+    eStateEntanglingForClose,
+
+    // When entangled() is received we send all the messages in the
+    // mMessagesForTheOtherPort to the actor and we change the state to
+    // StateEntangled. At this point the port is entangled with the other. We
+    // send and receive messages.
+    // If the port queue is not enabled, the received messages are stored in
+    // the mMessages.
+    eStateEntangled,
+
+    // When the port is cloned or disentangled we want to stop receiving
+    // messages. We call 'SendStopSendingData' to the actor and we wait for an
+    // answer. All the messages received between now and the
+    // 'StopSendingDataComfirmed are queued in the mMessages but not
+    // dispatched.
+    eStateDisentangling,
+
+    // When 'StopSendingDataConfirmed' is received, we can disentangle the port
+    // calling SendDisentangle in the actor because we are 100% sure that we
+    // don't receive any other message, so nothing will be lost.
+    // Disentangling the port we send all the messages from the mMessages
+    // though the actor.
+    eStateDisentangled,
+
+    // We are here if Close() has been called. We are disentangled but we can
+    // still send pending messages.
+    eStateDisentangledForClose
+  };
+
+  explicit MessagePort(nsIGlobalObject* aGlobal, State aState);
+  ~MessagePort();
+
+  void DisconnectFromOwner() override;
+
+  void Initialize(const nsID& aUUID, const nsID& aDestinationUUID,
+                  uint32_t aSequenceID, bool aNeutered, ErrorResult& aRv);
+
+  bool ConnectToPBackground();
+
+  // Dispatch events from the Message Queue using a nsRunnable.
+  void Dispatch();
+
+  void DispatchError();
+
+  void StartDisentangling();
+  void Disentangle();
+
+  void RemoveDocFromBFCache();
+
+  void CloseInternal(bool aSoftly);
+
+  // This method is meant to keep alive the MessagePort when this object is
+  // creating the actor and until the actor is entangled.
+  // We release the object when the port is closed or disentangled.
+  void UpdateMustKeepAlive();
+
+  bool IsCertainlyAliveForCC() const override { return mIsKeptAlive; }
+
+  RefPtr<StrongWorkerRef> mWorkerRef;
+
+  RefPtr<PostMessageRunnable> mPostMessageRunnable;
+
+  RefPtr<MessagePortChild> mActor;
+
+  RefPtr<MessagePort> mUnshippedEntangledPort;
+
+  RefPtr<RefMessageBodyService> mRefMessageBodyService;
+
+  nsTArray<RefPtr<SharedMessageBody>> mMessages;
+  nsTArray<RefPtr<SharedMessageBody>> mMessagesForTheOtherPort;
+
+  UniquePtr<MessagePortIdentifier> mIdentifier;
+
+  State mState;
+
+  bool mMessageQueueEnabled;
+
+  bool mIsKeptAlive;
+
+  // mHasBeenTransferredOrClosed is used to know if this port has been manually
+  // closed or transferred via postMessage. Note that if the entangled port is
+  // closed, this port is closed as well (see mState) but, just because close()
+  // has not been called directly, by spec, this port can still be transferred.
+  bool mHasBeenTransferredOrClosed;
+};
+
+}  // namespace mozilla::dom
+
+#endif  // mozilla_dom_MessagePort_h