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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_PreallocatedProcessManager_h
#define mozilla_PreallocatedProcessManager_h
#include "base/basictypes.h"
#include "mozilla/AlreadyAddRefed.h"
#include "nsStringFwd.h"
namespace mozilla {
namespace dom {
class ContentParent;
} // namespace dom
/**
* This class manages a ContentParent that it starts up ahead of any particular
* need. You can then call Take() to get this process and use it. Since we
* already started it up, it should be ready for use faster than if you'd
* created the process when you needed it.
*
* This class watches the dom.ipc.processPrelaunch.enabled pref. If it changes
* from false to true, it preallocates a process. If it changes from true to
* false, it kills the preallocated process, if any.
*
* We don't expect this pref to flip between true and false in production, but
* flipping the pref is important for tests.
*/
class PreallocatedProcessManagerImpl;
class PreallocatedProcessManager final {
typedef mozilla::dom::ContentParent ContentParent;
public:
static PreallocatedProcessManagerImpl* GetPPMImpl();
static bool Enabled();
/**
* Before first paint we don't want to allocate any processes in the
* background. To avoid that, the PreallocatedProcessManager won't start up
* any processes while there is a blocker active.
*/
static void AddBlocker(const nsACString& aRemoteType, ContentParent* aParent);
static void RemoveBlocker(const nsACString& aRemoteType,
ContentParent* aParent);
/**
* Take a preallocated process, if we have one. If we don't have a
* preallocated process to return, this returns null.
*
* If we use a preallocated process, it will schedule the start of
* another on Idle (AllocateOnIdle()).
*/
static already_AddRefed<ContentParent> Take(const nsACString& aRemoteType);
/**
* Note that a process was shut down, and should no longer be tracked as a
* preallocated process.
*/
static void Erase(ContentParent* aParent);
private:
PreallocatedProcessManager();
DISALLOW_EVIL_CONSTRUCTORS(PreallocatedProcessManager);
};
} // namespace mozilla
#endif // defined mozilla_PreallocatedProcessManager_h
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