1 files changed, 129 insertions, 0 deletions
diff --git a/ipc/glue/MessageLink.h b/ipc/glue/MessageLink.h
new file mode 100644
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--- /dev/null
+++ b/ipc/glue/MessageLink.h
@@ -0,0 +1,129 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=4 et :
+ */
+/* 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 ipc_glue_MessageLink_h
+#define ipc_glue_MessageLink_h 1
+
+#include <cstdint>
+#include "base/message_loop.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/ipc/Transport.h"
+
+namespace IPC {
+class Message;
+}
+
+namespace mozilla {
+namespace ipc {
+
+class MessageChannel;
+
+struct HasResultCodes {
+  enum Result {
+    MsgProcessed,
+    MsgDropped,
+    MsgNotKnown,
+    MsgNotAllowed,
+    MsgPayloadError,
+    MsgProcessingError,
+    MsgRouteError,
+    MsgValueError
+  };
+};
+
+enum Side : uint8_t { ParentSide, ChildSide, UnknownSide };
+
+class MessageLink {
+ public:
+  typedef IPC::Message Message;
+
+  explicit MessageLink(MessageChannel* aChan);
+  virtual ~MessageLink();
+
+  // This is called immediately before the MessageChannel destroys its
+  // MessageLink. See the implementation in ThreadLink for details.
+  virtual void PrepareToDestroy(){};
+
+  // n.b.: These methods all require that the channel monitor is
+  // held when they are invoked.
+  virtual void SendMessage(mozilla::UniquePtr<Message> msg) = 0;
+  virtual void SendClose() = 0;
+
+  virtual bool Unsound_IsClosed() const = 0;
+  virtual uint32_t Unsound_NumQueuedMessages() const = 0;
+
+ protected:
+  MessageChannel* mChan;
+};
+
+class ProcessLink : public MessageLink, public Transport::Listener {
+  void OnCloseChannel();
+  void OnChannelOpened();
+  void OnTakeConnectedChannel();
+
+  void AssertIOThread() const {
+    MOZ_ASSERT(mIOLoop == MessageLoop::current(), "not on I/O thread!");
+  }
+
+ public:
+  explicit ProcessLink(MessageChannel* chan);
+  virtual ~ProcessLink();
+
+  // The ProcessLink will register itself as the IPC::Channel::Listener on the
+  // transport passed here. If the transport already has a listener registered
+  // then a listener chain will be established (the ProcessLink listener
+  // methods will be called first and may call some methods on the original
+  // listener as well). Once the channel is closed (either via normal shutdown
+  // or a pipe error) the chain will be destroyed and the original listener
+  // will again be registered.
+  void Open(UniquePtr<Transport> aTransport, MessageLoop* aIOLoop, Side aSide);
+
+  // Run on the I/O thread, only when using inter-process link.
+  // These methods acquire the monitor and forward to the
+  // similarly named methods in AsyncChannel below
+  // (OnMessageReceivedFromLink(), etc)
+  virtual void OnMessageReceived(Message&& msg) override;
+  virtual void OnChannelConnected(int32_t peer_pid) override;
+  virtual void OnChannelError() override;
+
+  virtual void SendMessage(mozilla::UniquePtr<Message> msg) override;
+  virtual void SendClose() override;
+
+  virtual bool Unsound_IsClosed() const override;
+  virtual uint32_t Unsound_NumQueuedMessages() const override;
+
+ protected:
+  void OnChannelConnectError();
+
+ protected:
+  UniquePtr<Transport> mTransport;
+  MessageLoop* mIOLoop;                    // thread where IO happens
+  Transport::Listener* mExistingListener;  // channel's previous listener
+};
+
+class ThreadLink : public MessageLink {
+ public:
+  ThreadLink(MessageChannel* aChan, MessageChannel* aTargetChan);
+  virtual ~ThreadLink() = default;
+
+  virtual void PrepareToDestroy() override;
+
+  virtual void SendMessage(mozilla::UniquePtr<Message> msg) override;
+  virtual void SendClose() override;
+
+  virtual bool Unsound_IsClosed() const override;
+  virtual uint32_t Unsound_NumQueuedMessages() const override;
+
+ protected:
+  MessageChannel* mTargetChan;
+};
+
+}  // namespace ipc
+}  // namespace mozilla
+
+#endif  // ifndef ipc_glue_MessageLink_h