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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /ipc/glue/SendStream.h
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
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+/* -*- 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_ipc_SendStream_h
+#define mozilla_ipc_SendStream_h
+
+#include "mozilla/AlreadyAddRefed.h"
+#include "mozilla/ipc/PSendStreamChild.h"
+#include "mozilla/ipc/PSendStreamParent.h"
+
+class nsIInputStream;
+class nsIAsyncInputStream;
+
+namespace mozilla {
+
+namespace dom {
+class nsIContentChild;
+} // dom namespace
+
+namespace ipc {
+
+class PBackgroundChild;
+
+// The SendStream IPC actor is designed to push an nsIInputStream from child to
+// parent incrementally. This is mainly needed for streams such as nsPipe that
+// may not yet have all their data available when the stream must be sent across
+// an IPC boundary. While many streams are handled by SerializeInputStream(),
+// these streams cannot be serialized and must be sent using this actor.
+//
+// The SendStream actor only supports sending data from child to parent.
+//
+// The SendStream actor only support async, non-blocking streams because they
+// must be read inline on the main thread and Worker threads.
+//
+// In general, the creation and handling of the SendStream actor cannot be
+// abstracted away behind SerializeInputStream() because the actor must be
+// carefully managed. Specifically:
+//
+// 1) The data flow must be explicitly initiated by calling
+// SendStreamChild::Start() after the actor has been sent to the parent.
+// 2) If the actor is never sent to the parent, then the child code must
+// call SendStreamChild::StartDestroy() to avoid memory leaks.
+// 3) The SendStreamChild actor can only be used on threads that can be
+// guaranteed to stay alive as long as the actor is alive. Right now
+// this limits SendStream to the main thread and Worker threads.
+//
+// In general you should probably use the AutoIPCStreamChild RAII class
+// defined in InputStreamUtils.h instead of using SendStreamChild directly.
+class SendStreamChild : public PSendStreamChild
+{
+public:
+ // Create a SendStreamChild using a PContent IPC manager on the
+ // main thread. This can return nullptr if the provided stream is
+ // blocking.
+ static SendStreamChild*
+ Create(nsIAsyncInputStream* aInputStream, dom::nsIContentChild* aManager);
+
+ // Create a SendStreamChild using a PBackground IPC manager on the
+ // main thread or a Worker thread. This can return nullptr if the provided
+ // stream is blocking or if the Worker thread is already shutting down.
+ static SendStreamChild*
+ Create(nsIAsyncInputStream* aInputStream, PBackgroundChild* aManager);
+
+ // Start reading data from the nsIAsyncInputStream used to create the actor.
+ // This must be called after the actor is passed to the parent. If you
+ // use AutoIPCStream this is handled automatically.
+ virtual void
+ Start() = 0;
+
+ // Start cleaning up the actor. This must be called if the actor is never
+ // sent to the parent. If you use AutoIPCStream this is handled
+ // automatically.
+ virtual void
+ StartDestroy() = 0;
+
+protected:
+ virtual
+ ~SendStreamChild() = 0;
+};
+
+// On the parent side, you must simply call TakeReader() upon receiving a
+// reference to the SendStreamParent actor. You do not need to maintain a
+// reference to the actor itself.
+class SendStreamParent : public PSendStreamParent
+{
+public:
+ virtual already_AddRefed<nsIInputStream>
+ TakeReader() = 0;
+
+protected:
+ virtual
+ ~SendStreamParent() = 0;
+};
+
+} // namespace ipc
+} // namespace mozilla
+
+#endif // mozilla_ipc_SendStream_h