gecko-dev/ipc/glue/BackgroundChild.h

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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_backgroundchild_h__
#define mozilla_ipc_backgroundchild_h__
#include "base/process.h"
#include "mozilla/Attributes.h"
#include "mozilla/ipc/Transport.h"
class nsIDOMBlob;
class nsIIPCBackgroundChildCreateCallback;
namespace mozilla {
namespace dom {
class BlobImpl;
class ContentChild;
class ContentParent;
class PBlobChild;
} // namespace dom
namespace ipc {
class PBackgroundChild;
// This class allows access to the PBackground protocol. PBackground allows
// communication between any thread (in the parent or a child process) and a
// single background thread in the parent process. Each PBackgroundChild
// instance is tied to the thread on which it is created and must not be shared
// across threads. Each PBackgroundChild is unique and valid as long as its
// designated thread lives.
//
// Creation of PBackground is asynchronous. GetForCurrentThread() will return
// null until the sequence is complete. GetOrCreateForCurrentThread() will start
// the creation sequence and will call back via the
// nsIIPCBackgroundChildCreateCallback interface when completed. Thereafter
// (assuming success) GetForCurrentThread() will return the same actor every
// time. SynchronouslyCreateForCurrentThread() will spin the event loop until
// the BackgroundChild until the creation sequence is complete.
//
// CloseForCurrentThread() will close the current PBackground actor. Subsequent
// calls to GetForCurrentThread will return null. CloseForCurrentThread() may
// only be called exactly once for each thread-specific actor. Currently it is
// illegal to call this before the PBackground actor has been created.
//
// The PBackgroundChild actor and all its sub-protocol actors will be
// automatically destroyed when its designated thread completes.
class BackgroundChild final
{
friend class mozilla::dom::ContentChild;
friend class mozilla::dom::ContentParent;
typedef base::ProcessId ProcessId;
typedef mozilla::ipc::Transport Transport;
public:
// See above.
static PBackgroundChild*
GetForCurrentThread();
// See above.
static bool
GetOrCreateForCurrentThread(nsIIPCBackgroundChildCreateCallback* aCallback);
// See above.
static PBackgroundChild*
SynchronouslyCreateForCurrentThread();
static mozilla::dom::PBlobChild*
GetOrCreateActorForBlob(PBackgroundChild* aBackgroundActor,
nsIDOMBlob* aBlob);
static mozilla::dom::PBlobChild*
GetOrCreateActorForBlobImpl(PBackgroundChild* aBackgroundActor,
mozilla::dom::BlobImpl* aBlobImpl);
// See above.
static void
CloseForCurrentThread();
private:
// Only called by ContentChild or ContentParent.
static void
Startup();
};
} // namespace ipc
} // namespace mozilla
#endif // mozilla_ipc_backgroundchild_h__