/* -*- 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 "nsCOMPtr.h" #include "nsIObserver.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. * * The static methods here are implemented by forwarding calls on to a * PreallocatedProcessManagerImpl singleton class, so if you add a new static * method here, you'll need to write a corresponding public method on the * singleton. */ class PreallocatedProcessManager final { typedef mozilla::dom::ContentParent ContentParent; public: /** * Create a process after a delay. We wait for a period of time (specified * by the dom.ipc.processPrelaunch.delayMs pref), then wait for this process * to go idle, then allocate the new process. * * If the dom.ipc.processPrelaunch.enabled pref is false, or if we already * have a preallocated process, this function does nothing. */ static void AllocateAfterDelay(); /** * Create a process once this process goes idle. * * If the dom.ipc.processPrelaunch.enabled pref is false, or if we already * have a preallocated process, this function does nothing. */ static void AllocateOnIdle(); /** * Create a process right now. * * If the dom.ipc.processPrelaunch.enabled pref is false, or if we already * have a preallocated process, this function does nothing. */ static void AllocateNow(); /** * Take the preallocated process, if we have one. If we don't have one, this * returns null. * * If you call Take() twice in a row, the second call is guaranteed to return * null. * * After you Take() the preallocated process, you need to call one of the * Allocate* functions (or change the dom.ipc.processPrelaunch pref from * false to true) before we'll create a new process. */ static already_AddRefed<ContentParent> Take(); private: PreallocatedProcessManager(); DISALLOW_EVIL_CONSTRUCTORS(PreallocatedProcessManager); }; } // namespace mozilla #endif // defined mozilla_PreallocatedProcessManager_h