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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 */
#ifndef mozilla_ipc_ProtocolUtils_h
#define mozilla_ipc_ProtocolUtils_h 1
#include <cstddef>
#include <cstdint>
#include <utility>
#include "IPCMessageStart.h"
#include "base/basictypes.h"
#include "base/process.h"
#include "chrome/common/ipc_message.h"
#include "mojo/core/ports/port_ref.h"
#include "mozilla/AlreadyAddRefed.h"
#include "mozilla/Assertions.h"
#include "mozilla/Attributes.h"
#include "mozilla/FunctionRef.h"
#include "mozilla/Maybe.h"
#include "mozilla/Mutex.h"
#include "mozilla/RefPtr.h"
#include "mozilla/Scoped.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/ipc/MessageChannel.h"
#include "mozilla/ipc/MessageLink.h"
#include "mozilla/ipc/SharedMemory.h"
#include "mozilla/ipc/Shmem.h"
#include "nsTHashMap.h"
#include "nsDebug.h"
#include "nsISupports.h"
#include "nsTArrayForwardDeclare.h"
#include "nsTHashSet.h"
// XXX Things that could be replaced by a forward header
#include "mozilla/ipc/Transport.h" // for Transport
// XXX Things that could be moved to ProtocolUtils.cpp
#include "base/process_util.h" // for CloseProcessHandle
#include "prenv.h" // for PR_GetEnv
#if defined(ANDROID) && defined(DEBUG)
# include <android/log.h>
template <typename T>
class nsPtrHashKey;
// WARNING: this takes into account the private, special-message-type
// enum in ipc_channel.h. They need to be kept in sync.
namespace {
// XXX the max message ID is actually kuint32max now ... when this
// changed, the assumptions of the special message IDs changed in that
// they're not carving out messages from likely-unallocated space, but
// rather carving out messages from the end of space allocated to
// protocol 0. Oops! We can get away with this until protocol 0
// starts approaching its 65,536th message.
enum {
// Message types used by NodeChannel
INTRODUCE_MESSAGE_TYPE = kuint16max - 14,
BROADCAST_MESSAGE_TYPE = kuint16max - 13,
EVENT_MESSAGE_TYPE = kuint16max - 12,
// Message types used by MessageChannel
BUILD_ID_MESSAGE_TYPE = kuint16max - 7, // unused
GOODBYE_MESSAGE_TYPE = kuint16max - 3,
CANCEL_MESSAGE_TYPE = kuint16max - 2,
// kuint16max - 1 is used by ipc_channel.h.
} // namespace
class MessageLoop;
class PickleIterator;
class nsISerialEventTarget;
namespace mozilla {
class SchedulerGroup;
namespace dom {
class ContentParent;
} // namespace dom
namespace net {
class NeckoParent;
} // namespace net
namespace ipc {
#ifdef FUZZING
class ProtocolFuzzerHelper;
#ifdef XP_WIN
const base::ProcessHandle kInvalidProcessHandle = INVALID_HANDLE_VALUE;
// In theory, on Windows, this is a valid process ID, but in practice they are
// currently divisible by four. Process IDs share the kernel handle allocation
// code and they are guaranteed to be divisible by four.
// As this could change for process IDs we shouldn't generally rely on this
// property, however even if that were to change, it seems safe to rely on this
// particular value never being used.
const base::ProcessId kInvalidProcessId = kuint32max;
const base::ProcessHandle kInvalidProcessHandle = -1;
const base::ProcessId kInvalidProcessId = -1;
// Scoped base::ProcessHandle to ensure base::CloseProcessHandle is called.
struct ScopedProcessHandleTraits {
typedef base::ProcessHandle type;
static type empty() { return kInvalidProcessHandle; }
static void release(type aProcessHandle) {
if (aProcessHandle && aProcessHandle != kInvalidProcessHandle) {
typedef mozilla::Scoped<ScopedProcessHandleTraits> ScopedProcessHandle;
class ProtocolFdMapping;
class ProtocolCloneContext;
// Used to pass references to protocol actors across the wire.
// Actors created on the parent-side have a positive ID, and actors
// allocated on the child side have a negative ID.
struct ActorHandle {
int mId;
// What happens if Interrupt calls race?
enum RacyInterruptPolicy { RIPError, RIPChildWins, RIPParentWins };
enum class LinkStatus : uint8_t {
// The actor has not established a link yet, or the actor is no longer in use
// by IPC, and its 'Dealloc' method has been called or is being called.
// NOTE: This state is used instead of an explicit `Freed` state when IPC no
// longer holds references to the current actor as we currently re-open
// existing actors. Once we fix these poorly behaved actors, this loopback
// state can be split to have the final state not be the same as the initial
// state.
// A live link is connected to the other side of this actor.
// The link has begun being destroyed. Messages may still be received, but
// cannot be sent. (exception: sync/intr replies may be sent while Doomed).
// The link has been destroyed, and messages will no longer be sent or
// received.
typedef IPCMessageStart ProtocolId;
// Generated by IPDL compiler
const char* ProtocolIdToName(IPCMessageStart aId);
class IToplevelProtocol;
class ActorLifecycleProxy;
class WeakActorLifecycleProxy;
class IPDLResolverInner;
class UntypedManagedEndpoint;
class IProtocol : public HasResultCodes {
enum ActorDestroyReason {
typedef base::ProcessId ProcessId;
typedef IPC::Message Message;
typedef IPC::MessageInfo MessageInfo;
IProtocol(ProtocolId aProtoId, Side aSide)
: mId(0),
mToplevel(nullptr) {}
IToplevelProtocol* ToplevelProtocol() { return mToplevel; }
// The following methods either directly forward to the toplevel protocol, or
// almost directly do.
int32_t Register(IProtocol* aRouted);
int32_t RegisterID(IProtocol* aRouted, int32_t aId);
IProtocol* Lookup(int32_t aId);
void Unregister(int32_t aId);
Shmem::SharedMemory* CreateSharedMemory(size_t aSize,
SharedMemory::SharedMemoryType aType,
bool aUnsafe, int32_t* aId);
Shmem::SharedMemory* LookupSharedMemory(int32_t aId);
bool IsTrackingSharedMemory(Shmem::SharedMemory* aSegment);
bool DestroySharedMemory(Shmem& aShmem);
MessageChannel* GetIPCChannel();
const MessageChannel* GetIPCChannel() const;
// Sets an event target to which all messages for aActor will be
// dispatched. This method must be called before right before the SendPFoo
// message for aActor is sent. And SendPFoo *must* be called if
// SetEventTargetForActor is called. The receiver when calling
// SetEventTargetForActor must be the actor that will be the manager for
// aActor.
void SetEventTargetForActor(IProtocol* aActor,
nsISerialEventTarget* aEventTarget);
// Replace the event target for the messages of aActor. There must not be
// any messages of aActor in the task queue, or we might run into some
// unexpected behavior.
void ReplaceEventTargetForActor(IProtocol* aActor,
nsISerialEventTarget* aEventTarget);
nsISerialEventTarget* GetActorEventTarget();
already_AddRefed<nsISerialEventTarget> GetActorEventTarget(IProtocol* aActor);
ProcessId OtherPid() const;
// Actor lifecycle and other properties.
ProtocolId GetProtocolId() const { return mProtocolId; }
const char* GetProtocolName() const { return ProtocolIdToName(mProtocolId); }
int32_t Id() const { return mId; }
IProtocol* Manager() const { return mManager; }
ActorLifecycleProxy* GetLifecycleProxy() { return mLifecycleProxy; }
WeakActorLifecycleProxy* GetWeakLifecycleProxy();
Side GetSide() const { return mSide; }
bool CanSend() const { return mLinkStatus == LinkStatus::Connected; }
bool CanRecv() const {
return mLinkStatus == LinkStatus::Connected ||
mLinkStatus == LinkStatus::Doomed;
// Remove or deallocate a managee given its type.
virtual void RemoveManagee(int32_t, IProtocol*) = 0;
virtual void DeallocManagee(int32_t, IProtocol*) = 0;
Maybe<IProtocol*> ReadActor(const IPC::Message* aMessage,
PickleIterator* aIter, bool aNullable,
const char* aActorDescription,
int32_t aProtocolTypeId);
virtual Result OnMessageReceived(const Message& aMessage) = 0;
virtual Result OnMessageReceived(const Message& aMessage,
Message*& aReply) = 0;
virtual Result OnCallReceived(const Message& aMessage, Message*& aReply) = 0;
bool AllocShmem(size_t aSize, Shmem::SharedMemory::SharedMemoryType aType,
Shmem* aOutMem);
bool AllocUnsafeShmem(size_t aSize,
Shmem::SharedMemory::SharedMemoryType aType,
Shmem* aOutMem);
bool DeallocShmem(Shmem& aMem);
void FatalError(const char* const aErrorMsg) const;
virtual void HandleFatalError(const char* aErrorMsg) const;
virtual ~IProtocol();
friend class IToplevelProtocol;
friend class ActorLifecycleProxy;
friend class IPDLResolverInner;
friend class UntypedManagedEndpoint;
void SetId(int32_t aId);
// We have separate functions because the accessibility code manually
// calls SetManager.
void SetManager(IProtocol* aManager);
// Sets the manager for the protocol and registers the protocol with
// its manager, setting up channels for the protocol as well. Not
// for use outside of IPDL.
void SetManagerAndRegister(IProtocol* aManager);
void SetManagerAndRegister(IProtocol* aManager, int32_t aId);
// Helpers for calling `Send` on our underlying IPC channel.
bool ChannelSend(IPC::Message* aMsg);
bool ChannelSend(IPC::Message* aMsg, IPC::Message* aReply);
bool ChannelCall(IPC::Message* aMsg, IPC::Message* aReply);
template <typename Value>
void ChannelSend(IPC::Message* aMsg, ResolveCallback<Value>&& aResolve,
RejectCallback&& aReject) {
UniquePtr<IPC::Message> msg(aMsg);
if (CanSend()) {
GetIPCChannel()->Send(std::move(msg), this, std::move(aResolve),
} else {
NS_WARNING("IPC message discarded: actor cannot send");
// Collect all actors managed by this object in an array. To make this safer
// to iterate, `ActorLifecycleProxy` references are returned rather than raw
// actor pointers.
virtual void AllManagedActors(
nsTArray<RefPtr<ActorLifecycleProxy>>& aActors) const = 0;
// Internal method called when the actor becomes connected.
void ActorConnected();
// Called immediately before setting the actor state to doomed, and triggering
// async actor destruction. Messages may be sent from this callback, but no
// later.
// FIXME(nika): This is currently unused!
virtual void ActorDoom() {}
void DoomSubtree();
// Called when the actor has been destroyed due to an error, a __delete__
// message, or a __doom__ reply.
virtual void ActorDestroy(ActorDestroyReason aWhy) {}
void DestroySubtree(ActorDestroyReason aWhy);
// Called when IPC has acquired its first reference to the actor. This method
// may take references which will later be freed by `ActorDealloc`.
virtual void ActorAlloc() {}
// Called when IPC has released its final reference to the actor. It will call
// the dealloc method, causing the actor to be actually freed.
// The actor has been freed after this method returns.
virtual void ActorDealloc() {
if (Manager()) {
Manager()->DeallocManagee(mProtocolId, this);
static const int32_t kNullActorId = 0;
static const int32_t kFreedActorId = 1;
int32_t mId;
ProtocolId mProtocolId;
Side mSide;
LinkStatus mLinkStatus;
ActorLifecycleProxy* mLifecycleProxy;
IProtocol* mManager;
IToplevelProtocol* mToplevel;
#define IPC_OK() mozilla::ipc::IPCResult::Ok()
#define IPC_FAIL(actor, why) \
mozilla::ipc::IPCResult::Fail(WrapNotNull(actor), __func__, (why))
#define IPC_FAIL_NO_REASON(actor) \
mozilla::ipc::IPCResult::Fail(WrapNotNull(actor), __func__)
* All message deserializer and message handler should return this
* type via above macros. We use a less generic name here to avoid
* conflict with mozilla::Result because we have quite a few using
* namespace mozilla::ipc; in the code base.
class IPCResult {
static IPCResult Ok() { return IPCResult(true); }
static IPCResult Fail(NotNull<IProtocol*> aActor, const char* aWhere,
const char* aWhy = "");
MOZ_IMPLICIT operator bool() const { return mSuccess; }
explicit IPCResult(bool aResult) : mSuccess(aResult) {}
bool mSuccess;
template <class PFooSide>
class Endpoint;
template <class PFooSide>
class ManagedEndpoint;
* All top-level protocols should inherit this class.
* IToplevelProtocol tracks all top-level protocol actors created from
* this protocol actor.
class IToplevelProtocol : public IProtocol {
#ifdef FUZZING
friend class mozilla::ipc::ProtocolFuzzerHelper;
template <class PFooSide>
friend class Endpoint;
explicit IToplevelProtocol(const char* aName, ProtocolId aProtoId,
Side aSide);
~IToplevelProtocol() = default;
// Shadow methods on IProtocol which are implemented directly on toplevel
// actors.
int32_t Register(IProtocol* aRouted);
int32_t RegisterID(IProtocol* aRouted, int32_t aId);
IProtocol* Lookup(int32_t aId);
void Unregister(int32_t aId);
Shmem::SharedMemory* CreateSharedMemory(size_t aSize,
SharedMemory::SharedMemoryType aType,
bool aUnsafe, int32_t* aId);
Shmem::SharedMemory* LookupSharedMemory(int32_t aId);
bool IsTrackingSharedMemory(Shmem::SharedMemory* aSegment);
bool DestroySharedMemory(Shmem& aShmem);
MessageChannel* GetIPCChannel() { return &mChannel; }
const MessageChannel* GetIPCChannel() const { return &mChannel; }
// NOTE: The target actor's Manager must already be set.
void SetEventTargetForActorInternal(IProtocol* aActor,
nsISerialEventTarget* aEventTarget);
void ReplaceEventTargetForActor(IProtocol* aActor,
nsISerialEventTarget* aEventTarget);
nsISerialEventTarget* GetActorEventTarget();
already_AddRefed<nsISerialEventTarget> GetActorEventTarget(IProtocol* aActor);
ProcessId OtherPid() const;
void SetOtherProcessId(base::ProcessId aOtherPid);
virtual void OnChannelClose() = 0;
virtual void OnChannelError() = 0;
virtual void ProcessingError(Result aError, const char* aMsgName) {}
bool Open(ScopedPort aPort, base::ProcessId aOtherPid);
bool Open(MessageChannel* aChannel, nsISerialEventTarget* aEventTarget,
mozilla::ipc::Side aSide = mozilla::ipc::UnknownSide);
// Open a toplevel actor such that both ends of the actor's channel are on
// the same thread. This method should be called on the thread to perform
// the link.
// WARNING: Attempting to send a sync or intr message on the same thread
// will crash.
bool OpenOnSameThread(MessageChannel* aChannel,
mozilla::ipc::Side aSide = mozilla::ipc::UnknownSide);
* This sends a special message that is processed on the IO thread, so that
* other actors can know that the process will soon shutdown.
void NotifyImpendingShutdown();
void Close();
void SetReplyTimeoutMs(int32_t aTimeoutMs);
void DeallocShmems();
bool ShmemCreated(const Message& aMsg);
bool ShmemDestroyed(const Message& aMsg);
virtual bool ShouldContinueFromReplyTimeout() { return false; }
// WARNING: This function is called with the MessageChannel monitor held.
virtual void IntentionalCrash() { MOZ_CRASH("Intentional IPDL crash"); }
// The code here is only useful for fuzzing. It should not be used for any
// other purpose.
#ifdef DEBUG
// Returns true if we should simulate a timeout.
// WARNING: This is a testing-only function that is called with the
// MessageChannel monitor held. Don't do anything fancy here or we could
// deadlock.
virtual bool ArtificialTimeout() { return false; }
// Returns true if we want to cause the worker thread to sleep with the
// monitor unlocked.
virtual bool NeedArtificialSleep() { return false; }
// This function should be implemented to sleep for some amount of time on
// the worker thread. Will only be called if NeedArtificialSleep() returns
// true.
virtual void ArtificialSleep() {}
bool ArtificialTimeout() { return false; }
bool NeedArtificialSleep() { return false; }
void ArtificialSleep() {}
virtual void EnteredCxxStack() {}
virtual void ExitedCxxStack() {}
virtual void EnteredCall() {}
virtual void ExitedCall() {}
bool IsOnCxxStack() const;
virtual RacyInterruptPolicy MediateInterruptRace(const MessageInfo& parent,
const MessageInfo& child) {
return RIPChildWins;
* Return true if windows messages can be handled while waiting for a reply
* to a sync IPDL message.
virtual bool HandleWindowsMessages(const Message& aMsg) const { return true; }
virtual void OnEnteredSyncSend() {}
virtual void OnExitedSyncSend() {}
virtual void ProcessRemoteNativeEventsInInterruptCall() {}
virtual void OnChannelReceivedMessage(const Message& aMsg) {}
void OnIPCChannelOpened() { ActorConnected(); }
already_AddRefed<nsISerialEventTarget> GetMessageEventTarget(
const Message& aMsg);
base::ProcessId OtherPidMaybeInvalid() const { return mOtherPid; }
int32_t NextId();
template <class T>
using IDMap = nsTHashMap<nsUint32HashKey, T>;
base::ProcessId mOtherPid;
// Used to be on mState
int32_t mLastLocalId;
IDMap<IProtocol*> mActorMap;
IDMap<Shmem::SharedMemory*> mShmemMap;
// XXX: We no longer need mEventTargetMap for Quantum DOM, so it may be
// worthwhile to remove it before people start depending on it for other weird
// things.
Mutex mEventTargetMutex;
IDMap<nsCOMPtr<nsISerialEventTarget>> mEventTargetMap;
MessageChannel mChannel;
class IShmemAllocator {
virtual bool AllocShmem(size_t aSize,
mozilla::ipc::SharedMemory::SharedMemoryType aShmType,
mozilla::ipc::Shmem* aShmem) = 0;
virtual bool AllocUnsafeShmem(
size_t aSize, mozilla::ipc::SharedMemory::SharedMemoryType aShmType,
mozilla::ipc::Shmem* aShmem) = 0;
virtual bool DeallocShmem(mozilla::ipc::Shmem& aShmem) = 0;
virtual bool AllocShmem( \
size_t aSize, mozilla::ipc::SharedMemory::SharedMemoryType aShmType, \
mozilla::ipc::Shmem* aShmem) override { \
return aImplClass::AllocShmem(aSize, aShmType, aShmem); \
} \
virtual bool AllocUnsafeShmem( \
size_t aSize, mozilla::ipc::SharedMemory::SharedMemoryType aShmType, \
mozilla::ipc::Shmem* aShmem) override { \
return aImplClass::AllocUnsafeShmem(aSize, aShmType, aShmem); \
} \
virtual bool DeallocShmem(mozilla::ipc::Shmem& aShmem) override { \
return aImplClass::DeallocShmem(aShmem); \
inline bool LoggingEnabled() {
#if defined(DEBUG) || defined(FUZZING)
return !!PR_GetEnv("MOZ_IPC_MESSAGE_LOG");
return false;
#if defined(DEBUG) || defined(FUZZING)
bool LoggingEnabledFor(const char* aTopLevelProtocol, const char* aFilter);
inline bool LoggingEnabledFor(const char* aTopLevelProtocol) {
#if defined(DEBUG) || defined(FUZZING)
return LoggingEnabledFor(aTopLevelProtocol, PR_GetEnv("MOZ_IPC_MESSAGE_LOG"));
return false;
MOZ_NEVER_INLINE void LogMessageForProtocol(const char* aTopLevelProtocol,
base::ProcessId aOtherPid,
const char* aContextDescription,
uint32_t aMessageId,
MessageDirection aDirection);
MOZ_NEVER_INLINE void ProtocolErrorBreakpoint(const char* aMsg);
// The code generator calls this function for errors which come from the
// methods of protocols. Doing this saves codesize by making the error
// cases significantly smaller.
MOZ_NEVER_INLINE void FatalError(const char* aMsg, bool aIsParent);
// The code generator calls this function for errors which are not
// protocol-specific: errors in generated struct methods or errors in
// transition functions, for instance. Doing this saves codesize by
// by making the error cases significantly smaller.
MOZ_NEVER_INLINE void LogicError(const char* aMsg);
MOZ_NEVER_INLINE void ActorIdReadError(const char* aActorDescription);
MOZ_NEVER_INLINE void BadActorIdError(const char* aActorDescription);
MOZ_NEVER_INLINE void ActorLookupError(const char* aActorDescription);
MOZ_NEVER_INLINE void MismatchedActorTypeError(const char* aActorDescription);
MOZ_NEVER_INLINE void UnionTypeReadError(const char* aUnionName);
MOZ_NEVER_INLINE void ArrayLengthReadError(const char* aElementName);
MOZ_NEVER_INLINE void SentinelReadError(const char* aElementName);
#if defined(XP_WIN)
// This is a restricted version of Windows' DuplicateHandle() function
// that works inside the sandbox and can send handles but not retrieve
// them. Unlike DuplicateHandle(), it takes a process ID rather than
// a process handle. It returns true on success, false otherwise.
bool DuplicateHandle(HANDLE aSourceHandle, DWORD aTargetProcessId,
HANDLE* aTargetHandle, DWORD aDesiredAccess,
DWORD aOptions);
* Annotate the crash reporter with the error code from the most recent system
* call. Returns the system error.
void AnnotateSystemError();
// The ActorLifecycleProxy is a helper type used internally by IPC to maintain a
// maybe-owning reference to an IProtocol object. For well-behaved actors
// which are not freed until after their `Dealloc` method is called, a
// reference to an actor's `ActorLifecycleProxy` object is an owning one, as the
// `Dealloc` method will only be called when all references to the
// `ActorLifecycleProxy` are released.
// Unfortunately, some actors may be destroyed before their `Dealloc` method
// is called. For these actors, `ActorLifecycleProxy` acts as a weak pointer,
// and will begin to return `nullptr` from its `Get()` method once the
// corresponding actor object has been destroyed.
// When calling a `Recv` method, IPC will hold a `ActorLifecycleProxy` reference
// to the target actor, meaning that well-behaved actors can behave as though a
// strong reference is being held.
// Generic IPC code MUST treat ActorLifecycleProxy references as weak
// references!
class ActorLifecycleProxy {
IProtocol* Get() { return mActor; }
WeakActorLifecycleProxy* GetWeakProxy();
friend class IProtocol;
explicit ActorLifecycleProxy(IProtocol* aActor);
ActorLifecycleProxy(const ActorLifecycleProxy&) = delete;
ActorLifecycleProxy& operator=(const ActorLifecycleProxy&) = delete;
IProtocol* MOZ_NON_OWNING_REF mActor;
// Hold a reference to the actor's manager's ActorLifecycleProxy to help
// prevent it from dying while we're still alive!
RefPtr<ActorLifecycleProxy> mManager;
// When requested, the current self-referencing weak reference for this
// ActorLifecycleProxy.
RefPtr<WeakActorLifecycleProxy> mWeakProxy;
// Unlike ActorLifecycleProxy, WeakActorLifecycleProxy only holds a weak
// reference to both the proxy and the actual actor, meaning that holding this
// type will not attempt to keep the actor object alive.
// This type is safe to hold on threads other than the actor's thread, but is
// _NOT_ safe to access on other threads, as actors and ActorLifecycleProxy
// objects are not threadsafe.
class WeakActorLifecycleProxy final {
// May only be called on the actor's event target.
// Will return `nullptr` if the actor has already been destroyed from IPC's
// point of view.
IProtocol* Get() const;
// Safe to call on any thread.
nsISerialEventTarget* ActorEventTarget() const { return mActorEventTarget; }
friend class ActorLifecycleProxy;
explicit WeakActorLifecycleProxy(ActorLifecycleProxy* aProxy);
WeakActorLifecycleProxy(const WeakActorLifecycleProxy&) = delete;
WeakActorLifecycleProxy& operator=(const WeakActorLifecycleProxy&) = delete;
// This field may only be accessed on the actor's thread, and will be
// automatically cleared when the ActorLifecycleProxy is destroyed.
ActorLifecycleProxy* MOZ_NON_OWNING_REF mProxy;
// The serial event target which owns the actor, and is the only thread where
// it is OK to access the ActorLifecycleProxy.
const nsCOMPtr<nsISerialEventTarget> mActorEventTarget;
class IPDLResolverInner final {
explicit IPDLResolverInner(UniquePtr<IPC::Message> aReply, IProtocol* aActor);
template <typename F>
void Resolve(F&& aWrite) {
ResolveOrReject(true, aWrite);
void ResolveOrReject(bool aResolve,
FunctionRef<void(IPC::Message*, IProtocol*)> aWrite);
void Destroy();
UniquePtr<IPC::Message> mReply;
RefPtr<WeakActorLifecycleProxy> mWeakProxy;
} // namespace ipc
template <typename Protocol>
class ManagedContainer {
using iterator = typename nsTArray<Protocol*>::const_iterator;
iterator begin() const { return mArray.begin(); }
iterator end() const { return mArray.end(); }
iterator cbegin() const { return begin(); }
iterator cend() const { return end(); }
bool IsEmpty() const { return mArray.IsEmpty(); }
uint32_t Count() const { return mArray.Length(); }
void ToArray(nsTArray<Protocol*>& aArray) const {
bool EnsureRemoved(Protocol* aElement) {
return mArray.RemoveElementSorted(aElement);
void Insert(Protocol* aElement) {
// Equivalent to `InsertElementSorted`, avoiding inserting a duplicate
// element.
size_t index = mArray.IndexOfFirstElementGt(aElement);
if (index == 0 || mArray[index - 1] != aElement) {
mArray.InsertElementAt(index, aElement);
void Clear() { mArray.Clear(); }
nsTArray<Protocol*> mArray;
template <typename Protocol>
Protocol* LoneManagedOrNullAsserts(
const ManagedContainer<Protocol>& aManagees) {
if (aManagees.IsEmpty()) {
return nullptr;
MOZ_ASSERT(aManagees.Count() == 1);
return *aManagees.cbegin();
template <typename Protocol>
Protocol* SingleManagedOrNull(const ManagedContainer<Protocol>& aManagees) {
if (aManagees.Count() != 1) {
return nullptr;
return *aManagees.cbegin();
} // namespace mozilla
#endif // mozilla_ipc_ProtocolUtils_h