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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 https://mozilla.org/MPL/2.0/. */
+
+#ifndef IPC_GLUE_ENDPOINT_H_
+#define IPC_GLUE_ENDPOINT_H_
+
+#include <utility>
+#include "CrashAnnotations.h"
+#include "base/process.h"
+#include "base/process_util.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/ipc/MessageLink.h"
+#include "mozilla/ipc/ProtocolUtils.h"
+#include "mozilla/ipc/NodeController.h"
+#include "mozilla/ipc/ScopedPort.h"
+#include "nsXULAppAPI.h"
+#include "nscore.h"
+
+namespace IPC {
+template <class P>
+struct ParamTraits;
+}
+
+namespace mozilla {
+namespace ipc {
+
+namespace endpoint_detail {
+
+template <class T>
+static auto ActorNeedsOtherPidHelper(int)
+ -> decltype(std::declval<T>().OtherPid(), std::true_type{});
+template <class>
+static auto ActorNeedsOtherPidHelper(long) -> std::false_type;
+
+template <typename T>
+constexpr bool ActorNeedsOtherPid =
+ decltype(ActorNeedsOtherPidHelper<T>(0))::value;
+
+} // namespace endpoint_detail
+
+struct PrivateIPDLInterface {};
+
+class UntypedEndpoint {
+ public:
+ using ProcessId = base::ProcessId;
+
+ UntypedEndpoint() = default;
+
+ UntypedEndpoint(const PrivateIPDLInterface&, ScopedPort aPort,
+ const nsID& aMessageChannelId,
+ ProcessId aMyPid = base::kInvalidProcessId,
+ ProcessId aOtherPid = base::kInvalidProcessId)
+ : mPort(std::move(aPort)),
+ mMessageChannelId(aMessageChannelId),
+ mMyPid(aMyPid),
+ mOtherPid(aOtherPid) {}
+
+ UntypedEndpoint(const UntypedEndpoint&) = delete;
+ UntypedEndpoint(UntypedEndpoint&& aOther) = default;
+
+ UntypedEndpoint& operator=(const UntypedEndpoint&) = delete;
+ UntypedEndpoint& operator=(UntypedEndpoint&& aOther) = default;
+
+ // This method binds aActor to this endpoint. After this call, the actor can
+ // be used to send and receive messages. The endpoint becomes invalid.
+ //
+ // If specified, aEventTarget is the target the actor will be bound to, and
+ // must be on the current thread. Otherwise, GetCurrentSerialEventTarget() is
+ // used.
+ bool Bind(IToplevelProtocol* aActor,
+ nsISerialEventTarget* aEventTarget = nullptr) {
+ MOZ_RELEASE_ASSERT(IsValid());
+ MOZ_RELEASE_ASSERT(mMyPid == base::kInvalidProcessId ||
+ mMyPid == base::GetCurrentProcId());
+ MOZ_RELEASE_ASSERT(!aEventTarget || aEventTarget->IsOnCurrentThread());
+ return aActor->Open(std::move(mPort), mMessageChannelId, mOtherPid,
+ aEventTarget);
+ }
+
+ bool IsValid() const { return mPort.IsValid(); }
+
+ protected:
+ friend struct IPC::ParamTraits<UntypedEndpoint>;
+
+ ScopedPort mPort;
+ nsID mMessageChannelId{};
+ ProcessId mMyPid = base::kInvalidProcessId;
+ ProcessId mOtherPid = base::kInvalidProcessId;
+};
+
+/**
+ * An endpoint represents one end of a partially initialized IPDL channel. To
+ * set up a new top-level protocol:
+ *
+ * Endpoint<PFooParent> parentEp;
+ * Endpoint<PFooChild> childEp;
+ * nsresult rv;
+ * rv = PFoo::CreateEndpoints(&parentEp, &childEp);
+ *
+ * Endpoints can be passed in IPDL messages or sent to other threads using
+ * PostTask. Once an Endpoint has arrived at its destination process and thread,
+ * you need to create the top-level actor and bind it to the endpoint:
+ *
+ * FooParent* parent = new FooParent();
+ * bool rv1 = parentEp.Bind(parent, processActor);
+ * bool rv2 = parent->SendBar(...);
+ *
+ * (See Bind below for an explanation of processActor.) Once the actor is bound
+ * to the endpoint, it can send and receive messages.
+ *
+ * If creating endpoints for a [NeedsOtherPid] actor, you're required to also
+ * pass in parentPid and childPid, which are the pids of the processes in which
+ * the parent and child endpoints will be used.
+ */
+template <class PFooSide>
+class Endpoint final : public UntypedEndpoint {
+ public:
+ using UntypedEndpoint::IsValid;
+ using UntypedEndpoint::UntypedEndpoint;
+
+ base::ProcessId OtherPid() const {
+ static_assert(
+ endpoint_detail::ActorNeedsOtherPid<PFooSide>,
+ "OtherPid may only be called on Endpoints for actors which are "
+ "[NeedsOtherPid]");
+ MOZ_RELEASE_ASSERT(mOtherPid != base::kInvalidProcessId);
+ return mOtherPid;
+ }
+
+ // This method binds aActor to this endpoint. After this call, the actor can
+ // be used to send and receive messages. The endpoint becomes invalid.
+ //
+ // If specified, aEventTarget is the target the actor will be bound to, and
+ // must be on the current thread. Otherwise, GetCurrentSerialEventTarget() is
+ // used.
+ bool Bind(PFooSide* aActor, nsISerialEventTarget* aEventTarget = nullptr) {
+ return UntypedEndpoint::Bind(aActor, aEventTarget);
+ }
+};
+
+#if defined(XP_MACOSX)
+void AnnotateCrashReportWithErrno(CrashReporter::Annotation tag, int error);
+#else
+inline void AnnotateCrashReportWithErrno(CrashReporter::Annotation tag,
+ int error) {}
+#endif
+
+// This function is used internally to create a pair of Endpoints. See the
+// comment above Endpoint for a description of how it might be used.
+template <class PFooParent, class PFooChild>
+nsresult CreateEndpoints(const PrivateIPDLInterface& aPrivate,
+ Endpoint<PFooParent>* aParentEndpoint,
+ Endpoint<PFooChild>* aChildEndpoint) {
+ static_assert(
+ !endpoint_detail::ActorNeedsOtherPid<PFooParent> &&
+ !endpoint_detail::ActorNeedsOtherPid<PFooChild>,
+ "Pids are required when creating endpoints for [NeedsOtherPid] actors");
+
+ auto [parentPort, childPort] =
+ NodeController::GetSingleton()->CreatePortPair();
+ nsID channelId = nsID::GenerateUUID();
+ *aParentEndpoint =
+ Endpoint<PFooParent>(aPrivate, std::move(parentPort), channelId);
+ *aChildEndpoint =
+ Endpoint<PFooChild>(aPrivate, std::move(childPort), channelId);
+ return NS_OK;
+}
+
+template <class PFooParent, class PFooChild>
+nsresult CreateEndpoints(const PrivateIPDLInterface& aPrivate,
+ base::ProcessId aParentDestPid,
+ base::ProcessId aChildDestPid,
+ Endpoint<PFooParent>* aParentEndpoint,
+ Endpoint<PFooChild>* aChildEndpoint) {
+ MOZ_RELEASE_ASSERT(aParentDestPid != base::kInvalidProcessId);
+ MOZ_RELEASE_ASSERT(aChildDestPid != base::kInvalidProcessId);
+
+ auto [parentPort, childPort] =
+ NodeController::GetSingleton()->CreatePortPair();
+ nsID channelId = nsID::GenerateUUID();
+ *aParentEndpoint =
+ Endpoint<PFooParent>(aPrivate, std::move(parentPort), channelId,
+ aParentDestPid, aChildDestPid);
+ *aChildEndpoint = Endpoint<PFooChild>(
+ aPrivate, std::move(childPort), channelId, aChildDestPid, aParentDestPid);
+ return NS_OK;
+}
+
+class UntypedManagedEndpoint {
+ public:
+ bool IsValid() const { return mInner.isSome(); }
+
+ UntypedManagedEndpoint(const UntypedManagedEndpoint&) = delete;
+ UntypedManagedEndpoint& operator=(const UntypedManagedEndpoint&) = delete;
+
+ protected:
+ UntypedManagedEndpoint() = default;
+ explicit UntypedManagedEndpoint(IProtocol* aActor);
+
+ UntypedManagedEndpoint(UntypedManagedEndpoint&& aOther) noexcept
+ : mInner(std::move(aOther.mInner)) {
+ aOther.mInner = Nothing();
+ }
+ UntypedManagedEndpoint& operator=(UntypedManagedEndpoint&& aOther) noexcept {
+ this->~UntypedManagedEndpoint();
+ new (this) UntypedManagedEndpoint(std::move(aOther));
+ return *this;
+ }
+
+ ~UntypedManagedEndpoint() noexcept;
+
+ bool BindCommon(IProtocol* aActor, IProtocol* aManager);
+
+ private:
+ friend struct IPDLParamTraits<UntypedManagedEndpoint>;
+
+ struct Inner {
+ // Pointers to the toplevel actor which will manage this connection. When
+ // created, only `mOtherSide` will be set, and will reference the
+ // toplevel actor which the other side is managed by. After being sent over
+ // IPC, only `mToplevel` will be set, and will be the toplevel actor for the
+ // channel which received the IPC message.
+ RefPtr<WeakActorLifecycleProxy> mOtherSide;
+ RefPtr<WeakActorLifecycleProxy> mToplevel;
+
+ int32_t mId = 0;
+ ProtocolId mType = LastMsgIndex;
+ int32_t mManagerId = 0;
+ ProtocolId mManagerType = LastMsgIndex;
+ };
+ Maybe<Inner> mInner;
+};
+
+/**
+ * A managed endpoint represents one end of a partially initialized managed
+ * IPDL actor. It is used for situations where the usual IPDL Constructor
+ * methods do not give sufficient control over the construction of actors, such
+ * as when constructing actors within replies, or constructing multiple related
+ * actors simultaneously.
+ *
+ * FooParent* parent = new FooParent();
+ * ManagedEndpoint<PFooChild> childEp = parentMgr->OpenPFooEndpoint(parent);
+ *
+ * ManagedEndpoints should be sent using IPDL messages or other mechanisms to
+ * the other side of the manager channel. Once the ManagedEndpoint has arrived
+ * at its destination, you can create the actor, and bind it to the endpoint.
+ *
+ * FooChild* child = new FooChild();
+ * childMgr->BindPFooEndpoint(childEp, child);
+ *
+ * WARNING: If the remote side of an endpoint has not been bound before it
+ * begins to receive messages, an IPC routing error will occur, likely causing
+ * a browser crash.
+ */
+template <class PFooSide>
+class ManagedEndpoint : public UntypedManagedEndpoint {
+ public:
+ ManagedEndpoint() = default;
+ ManagedEndpoint(ManagedEndpoint&&) noexcept = default;
+ ManagedEndpoint& operator=(ManagedEndpoint&&) noexcept = default;
+
+ ManagedEndpoint(const PrivateIPDLInterface&, IProtocol* aActor)
+ : UntypedManagedEndpoint(aActor) {}
+
+ bool Bind(const PrivateIPDLInterface&, PFooSide* aActor, IProtocol* aManager,
+ ManagedContainer<PFooSide>& aContainer) {
+ if (!BindCommon(aActor, aManager)) {
+ return false;
+ }
+ aContainer.Insert(aActor);
+ return true;
+ }
+
+ // Only invalid ManagedEndpoints can be equal, as valid endpoints are unique.
+ bool operator==(const ManagedEndpoint& _o) const {
+ return !IsValid() && !_o.IsValid();
+ }
+};
+
+} // namespace ipc
+} // namespace mozilla
+
+#endif // IPC_GLUE_ENDPOINT_H_
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