/* -*- 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/. */

#include "PermissionObserver.h"

#include "mozilla/dom/PermissionStatus.h"

#include "mozilla/Services.h"

#include "mozilla/UniquePtr.h"

#include "nsIObserverService.h"

#include "nsIPermission.h"

#include "PermissionUtils.h"

namespace mozilla {

namespace dom {

namespace {

PermissionObserver* gInstance = nullptr;

} // namespace

NS_IMPL_ISUPPORTS(PermissionObserver,

                  nsIObserver,

                  nsISupportsWeakReference)

PermissionObserver::PermissionObserver()

{

  MOZ_ASSERT(!gInstance);

}

PermissionObserver::~PermissionObserver()

{

  MOZ_ASSERT(mSinks.IsEmpty());

  MOZ_ASSERT(gInstance == this);

  gInstance = nullptr;

}

/* static */ already_AddRefed<PermissionObserver>

PermissionObserver::GetInstance()

{

  RefPtr<PermissionObserver> instance = gInstance;

  if (!instance) {

    instance = new PermissionObserver();

    nsCOMPtr<nsIObserverService> obs = services::GetObserverService();

    if (NS_WARN_IF(!obs)) {

      return nullptr;

    }

    nsresult rv = obs->AddObserver(instance, "perm-changed", true);

    if (NS_WARN_IF(NS_FAILED(rv))) {

      return nullptr;

    }

    gInstance = instance;

  }

  return instance.forget();

}

void

PermissionObserver::AddSink(PermissionStatus* aSink)

{

  MOZ_ASSERT(aSink);

  MOZ_ASSERT(!mSinks.Contains(aSink));

  mSinks.AppendElement(aSink);

}

void

PermissionObserver::RemoveSink(PermissionStatus* aSink)

{

  MOZ_ASSERT(aSink);

  MOZ_ASSERT(mSinks.Contains(aSink));

  mSinks.RemoveElement(aSink);

}

void

PermissionObserver::Notify(PermissionName aName, nsIPrincipal& aPrincipal)

{

  for (auto* sink : mSinks) {

    if (sink->mName != aName) {

      continue;

    }

    nsCOMPtr<nsIPrincipal> sinkPrincipal = sink->GetPrincipal();

    if (NS_WARN_IF(!sinkPrincipal) || !aPrincipal.Equals(sinkPrincipal)) {

      continue;

    }

    sink->PermissionChanged();

  }

}

NS_IMETHODIMP

PermissionObserver::Observe(nsISupports* aSubject,

                            const char* aTopic,

                            const char16_t* aData)

{

  MOZ_ASSERT(!strcmp(aTopic, "perm-changed"));

  if (mSinks.IsEmpty()) {

    return NS_OK;

  }

  nsCOMPtr<nsIPermission> perm = do_QueryInterface(aSubject);

  if (!perm) {

    return NS_OK;

  }

  nsCOMPtr<nsIPrincipal> principal;

  perm->GetPrincipal(getter_AddRefs(principal));

  if (!principal) {

    return NS_OK;

  }

  nsAutoCString type;

  perm->GetType(type);

  Maybe<PermissionName> permission = TypeToPermissionName(type.get());

  if (permission) {

    Notify(permission.value(), *principal);

  }

  return NS_OK;

}

} // namespace dom

} // namespace mozilla