/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: sw=2 ts=4 et :
 * 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/. */

#include "FunctionBrokerChild.h"
#include "FunctionBrokerThread.h"

#include "mozilla/ipc/Endpoint.h"

namespace mozilla::plugins {

FunctionBrokerChild* FunctionBrokerChild::sInstance = nullptr;

bool FunctionBrokerChild::IsDispatchThread() { return mThread->IsOnThread(); }

void FunctionBrokerChild::PostToDispatchThread(
    already_AddRefed<nsIRunnable>&& runnable) {
  mThread->Dispatch(std::move(runnable));
}

/* static */
bool FunctionBrokerChild::Initialize(
    Endpoint<PFunctionBrokerChild>&& aBrokerEndpoint) {
  MOZ_RELEASE_ASSERT(
      XRE_IsPluginProcess(),
      "FunctionBrokerChild can only be used in plugin processes");

  MOZ_ASSERT(!sInstance);
  FunctionBrokerThread* thread = FunctionBrokerThread::Create();
  if (!thread) {
    return false;
  }
  sInstance = new FunctionBrokerChild(thread, std::move(aBrokerEndpoint));
  return true;
}

/* static */
FunctionBrokerChild* FunctionBrokerChild::GetInstance() {
  MOZ_RELEASE_ASSERT(
      XRE_IsPluginProcess(),
      "FunctionBrokerChild can only be used in plugin processes");

  MOZ_ASSERT(sInstance, "Must initialize FunctionBrokerChild before using it");
  return sInstance;
}

FunctionBrokerChild::FunctionBrokerChild(
    FunctionBrokerThread* aThread, Endpoint<PFunctionBrokerChild>&& aEndpoint)
    : mThread(aThread),
      mShutdownDone(false),
      mMonitor("FunctionBrokerChild Lock") {
  MOZ_ASSERT(aThread);
  PostToDispatchThread(
      NewNonOwningRunnableMethod<Endpoint<PFunctionBrokerChild>&&>(
          "FunctionBrokerChild::Bind", this, &FunctionBrokerChild::Bind,
          std::move(aEndpoint)));
}

void FunctionBrokerChild::Bind(Endpoint<PFunctionBrokerChild>&& aEndpoint) {
  MOZ_RELEASE_ASSERT(mThread->IsOnThread());
  DebugOnly<bool> ok = aEndpoint.Bind(this);
  MOZ_ASSERT(ok);
}

void FunctionBrokerChild::ShutdownOnDispatchThread() {
  MOZ_ASSERT(mThread->IsOnThread());

  // Set mShutdownDone and notify waiting thread (if any) that we are done.
  MonitorAutoLock lock(mMonitor);
  mShutdownDone = true;
  mMonitor.Notify();
}

void FunctionBrokerChild::ActorDestroy(ActorDestroyReason aWhy) {
  MOZ_ASSERT(mThread->IsOnThread());

  // Queue up a task on the PD thread.  When that task is executed then
  // we know that anything queued before ActorDestroy has completed.
  // At that point, we can set mShutdownDone and alert any waiting
  // threads that it is safe to destroy us.
  sInstance->PostToDispatchThread(NewNonOwningRunnableMethod(
      "FunctionBrokerChild::ShutdownOnDispatchThread", sInstance,
      &FunctionBrokerChild::ShutdownOnDispatchThread));
}

void FunctionBrokerChild::Destroy() {
  MOZ_ASSERT(NS_IsMainThread());

  if (!sInstance) {
    return;
  }

  // mShutdownDone will tell us when ActorDestroy has been run and any tasks
  // on the FunctionBrokerThread have completed.  At that point, we can
  // safely delete the actor.
  {
    MonitorAutoLock lock(sInstance->mMonitor);
    while (!sInstance->mShutdownDone) {
      // Release lock and wait.  Regain lock when we are notified that
      // we have ShutdownOnDispatchThread.
      sInstance->mMonitor.Wait();
    }
  }

  delete sInstance;
  sInstance = nullptr;
}

}  // namespace mozilla::plugins