/* -*- 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 "StorageObserver.h"

#include "LocalStorageCache.h"
#include "StorageCommon.h"
#include "StorageDBThread.h"
#include "StorageIPC.h"
#include "StorageUtils.h"

#include "mozilla/BasePrincipal.h"
#include "nsIObserverService.h"
#include "nsIURI.h"
#include "nsIPermission.h"
#include "nsIIDNService.h"
#include "nsICookiePermission.h"

#include "nsPrintfCString.h"
#include "nsXULAppAPI.h"
#include "nsEscape.h"
#include "nsNetCID.h"
#include "mozilla/dom/LocalStorageCommon.h"
#include "mozilla/Preferences.h"
#include "mozilla/Services.h"
#include "mozilla/SpinEventLoopUntil.h"
#include "nsServiceManagerUtils.h"

namespace mozilla::dom {

using namespace StorageUtils;

static const char kStartupTopic[] = "sessionstore-windows-restored";
static const uint32_t kStartupDelay = 0;

const char kTestingPref[] = "dom.storage.testing";

constexpr auto kPrivateBrowsingPattern = u"{ \"privateBrowsingId\": 1 }"_ns;

NS_IMPL_ISUPPORTS(StorageObserver, nsIObserver, nsINamed,
                  nsISupportsWeakReference)

StorageObserver* StorageObserver::sSelf = nullptr;

// static
nsresult StorageObserver::Init() {
  static_assert(kPrivateBrowsingIdCount * sizeof(mBackgroundThread[0]) ==
                sizeof(mBackgroundThread));
  if (sSelf) {
    return NS_OK;
  }

  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
  if (!obs) {
    return NS_ERROR_UNEXPECTED;
  }

  sSelf = new StorageObserver();
  NS_ADDREF(sSelf);

  // Chrome clear operations.
  obs->AddObserver(sSelf, kStartupTopic, true);
  obs->AddObserver(sSelf, "cookie-changed", true);
  obs->AddObserver(sSelf, "perm-changed", true);
  obs->AddObserver(sSelf, "last-pb-context-exited", true);
  obs->AddObserver(sSelf, "clear-origin-attributes-data", true);
  obs->AddObserver(sSelf, "dom-storage:clear-origin-attributes-data", true);
  obs->AddObserver(sSelf, "extension:purge-localStorage", true);
  obs->AddObserver(sSelf, "browser:purge-sessionStorage", true);

  // Shutdown
  obs->AddObserver(sSelf, "profile-after-change", true);
  if (XRE_IsParentProcess()) {
    obs->AddObserver(sSelf, "profile-before-change", true);
  }

  // Testing
#ifdef DOM_STORAGE_TESTS
  Preferences::RegisterCallbackAndCall(TestingPrefChanged, kTestingPref);
#endif

  return NS_OK;
}

// static
nsresult StorageObserver::Shutdown() {
  AssertIsOnMainThread();

  if (!sSelf) {
    return NS_ERROR_NOT_INITIALIZED;  // Is this always an error?
  }

  sSelf->mSinks.Clear();

  NS_RELEASE(sSelf);
  return NS_OK;
}

// static
void StorageObserver::TestingPrefChanged(const char* aPrefName,
                                         void* aClosure) {
  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
  if (!obs || !sSelf) {
    return;
  }

  if (Preferences::GetBool(kTestingPref)) {
    obs->AddObserver(sSelf, "domstorage-test-flush-force", true);
    if (XRE_IsParentProcess()) {
      // Only to forward to child process.
      obs->AddObserver(sSelf, "domstorage-test-flushed", true);
    }
    obs->AddObserver(sSelf, "domstorage-test-reload", true);
  } else {
    obs->RemoveObserver(sSelf, "domstorage-test-flush-force");
    if (XRE_IsParentProcess()) {
      // Only to forward to child process.
      obs->RemoveObserver(sSelf, "domstorage-test-flushed");
    }
    obs->RemoveObserver(sSelf, "domstorage-test-reload");
  }
}

void StorageObserver::AddSink(StorageObserverSink* aObs) {
  AssertIsOnMainThread();

  MOZ_ASSERT(sSelf);

  mSinks.AppendElement(aObs);
}

void StorageObserver::RemoveSink(StorageObserverSink* aObs) {
  AssertIsOnMainThread();

  MOZ_ASSERT(sSelf);

  mSinks.RemoveElement(aObs);
}

void StorageObserver::Notify(const char* aTopic,
                             const nsAString& aOriginAttributesPattern,
                             const nsACString& aOriginScope) {
  AssertIsOnMainThread();

  MOZ_ASSERT(sSelf);

  for (auto sink : mSinks.ForwardRange()) {
    sink->Observe(aTopic, aOriginAttributesPattern, aOriginScope);
  }
}

void StorageObserver::NoteBackgroundThread(const uint32_t aPrivateBrowsingId,
                                           nsIEventTarget* aBackgroundThread) {
  MOZ_RELEASE_ASSERT(aPrivateBrowsingId < kPrivateBrowsingIdCount);

  mBackgroundThread[aPrivateBrowsingId] = aBackgroundThread;
}

nsresult StorageObserver::GetOriginScope(const char16_t* aData,
                                         nsACString& aOriginScope) {
  nsresult rv;

  NS_ConvertUTF16toUTF8 domain(aData);

  nsAutoCString convertedDomain;
  nsCOMPtr<nsIIDNService> converter = do_GetService(NS_IDNSERVICE_CONTRACTID);
  if (converter) {
    // Convert the domain name to the ACE format
    rv = converter->ConvertUTF8toACE(domain, convertedDomain);
  } else {
    // In case the IDN service is not available, this is the best we can come
    // up with!
    rv = NS_EscapeURL(domain, esc_OnlyNonASCII | esc_AlwaysCopy,
                      convertedDomain, fallible);
  }
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  nsCString originScope;
  rv = CreateReversedDomain(convertedDomain, originScope);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  aOriginScope = originScope;
  return NS_OK;
}

NS_IMETHODIMP
StorageObserver::Observe(nsISupports* aSubject, const char* aTopic,
                         const char16_t* aData) {
  if (NS_WARN_IF(!sSelf)) {  // Shutdown took place
    return NS_OK;
  }

  nsresult rv;

  // Start the thread that opens the database.
  if (!strcmp(aTopic, kStartupTopic)) {
    MOZ_ASSERT(XRE_IsParentProcess());

    if (NextGenLocalStorageEnabled()) {
      return NS_OK;
    }

    nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
    obs->RemoveObserver(this, kStartupTopic);

    return NS_NewTimerWithObserver(getter_AddRefs(mDBThreadStartDelayTimer),
                                   this, nsITimer::TYPE_ONE_SHOT,
                                   kStartupDelay);
  }

  // Timer callback used to start the database a short timer after startup
  if (!strcmp(aTopic, NS_TIMER_CALLBACK_TOPIC)) {
    MOZ_ASSERT(XRE_IsParentProcess());
    MOZ_ASSERT(!NextGenLocalStorageEnabled());

    nsCOMPtr<nsITimer> timer = do_QueryInterface(aSubject);
    if (!timer) {
      return NS_ERROR_UNEXPECTED;
    }

    if (timer == mDBThreadStartDelayTimer) {
      mDBThreadStartDelayTimer = nullptr;

      for (const uint32_t id : {0, 1}) {
        StorageDBChild* storageChild = StorageDBChild::GetOrCreate(id);
        if (NS_WARN_IF(!storageChild)) {
          return NS_ERROR_FAILURE;
        }

        storageChild->SendStartup();
      }
    }

    return NS_OK;
  }

  // Clear everything, caches + database
  if (!strcmp(aTopic, "cookie-changed")) {
    if (!u"cleared"_ns.Equals(aData)) {
      return NS_OK;
    }

    if (!NextGenLocalStorageEnabled()) {
      for (const uint32_t id : {0, 1}) {
        StorageDBChild* storageChild = StorageDBChild::GetOrCreate(id);
        if (NS_WARN_IF(!storageChild)) {
          return NS_ERROR_FAILURE;
        }

        storageChild->AsyncClearAll();

        if (XRE_IsParentProcess()) {
          storageChild->SendClearAll();
        }
      }
    }

    Notify("cookie-cleared");

    return NS_OK;
  }

  // Clear from caches everything that has been stored
  // while in session-only mode
  if (!strcmp(aTopic, "perm-changed")) {
    // Check for cookie permission change
    nsCOMPtr<nsIPermission> perm(do_QueryInterface(aSubject));
    if (!perm) {
      return NS_OK;
    }

    nsAutoCString type;
    perm->GetType(type);
    if (type != "cookie"_ns) {
      return NS_OK;
    }

    uint32_t cap = 0;
    perm->GetCapability(&cap);
    if (!(cap & nsICookiePermission::ACCESS_SESSION) ||
        !u"deleted"_ns.Equals(nsDependentString(aData))) {
      return NS_OK;
    }

    nsCOMPtr<nsIPrincipal> principal;
    perm->GetPrincipal(getter_AddRefs(principal));
    if (!principal) {
      return NS_OK;
    }

    nsAutoCString originSuffix;
    BasePrincipal::Cast(principal)->OriginAttributesRef().CreateSuffix(
        originSuffix);

    nsAutoCString host;
    principal->GetHost(host);
    if (host.IsEmpty()) {
      return NS_OK;
    }

    nsAutoCString originScope;
    rv = CreateReversedDomain(host, originScope);
    NS_ENSURE_SUCCESS(rv, rv);

    Notify("session-only-cleared", NS_ConvertUTF8toUTF16(originSuffix),
           originScope);

    return NS_OK;
  }

  if (!strcmp(aTopic, "extension:purge-localStorage")) {
    if (NextGenLocalStorageEnabled()) {
      return NS_OK;
    }

    const char topic[] = "extension:purge-localStorage-caches";

    if (aData) {
      nsCString originScope;

      rv = GetOriginScope(aData, originScope);
      if (NS_WARN_IF(NS_FAILED(rv))) {
        return rv;
      }

      if (XRE_IsParentProcess()) {
        for (const uint32_t id : {0, 1}) {
          StorageDBChild* storageChild = StorageDBChild::GetOrCreate(id);
          if (NS_WARN_IF(!storageChild)) {
            return NS_ERROR_FAILURE;
          }

          storageChild->SendClearMatchingOrigin(originScope);
        }
      }

      Notify(topic, u""_ns, originScope);
    } else {
      for (const uint32_t id : {0, 1}) {
        StorageDBChild* storageChild = StorageDBChild::GetOrCreate(id);
        if (NS_WARN_IF(!storageChild)) {
          return NS_ERROR_FAILURE;
        }

        storageChild->AsyncClearAll();

        if (XRE_IsParentProcess()) {
          storageChild->SendClearAll();
        }
      }

      Notify(topic);
    }

    return NS_OK;
  }

  if (!strcmp(aTopic, "browser:purge-sessionStorage")) {
    if (aData) {
      nsCString originScope;
      rv = GetOriginScope(aData, originScope);
      if (NS_WARN_IF(NS_FAILED(rv))) {
        return rv;
      }

      Notify(aTopic, u""_ns, originScope);
    } else {
      Notify(aTopic, u""_ns, ""_ns);
    }

    return NS_OK;
  }

  // Clear all private-browsing caches
  if (!strcmp(aTopic, "last-pb-context-exited")) {
    if (NextGenLocalStorageEnabled()) {
      return NS_OK;
    }

    // We get the notification in both processes (parent and content), but the
    // clearing of the in-memory database should be triggered from the parent
    // process only to avoid creation of redundant clearing operations.
    // Also, if we create a new StorageDBChild instance late during content
    // process shutdown, then it might be leaked in debug builds because it
    // could happen that there is no chance to properly destroy it.
    if (XRE_IsParentProcess()) {
      // This doesn't use a loop with privateBrowsingId 0 and 1, since we only
      // need to clear the in-memory database which is represented by
      // privateBrowsingId 1.
      static const uint32_t id = 1;

      StorageDBChild* storageChild = StorageDBChild::GetOrCreate(id);
      if (NS_WARN_IF(!storageChild)) {
        return NS_ERROR_FAILURE;
      }

      OriginAttributesPattern pattern;
      if (!pattern.Init(kPrivateBrowsingPattern)) {
        NS_ERROR("Cannot parse origin attributes pattern");
        return NS_ERROR_FAILURE;
      }

      storageChild->SendClearMatchingOriginAttributes(pattern);
    }

    Notify("private-browsing-data-cleared", kPrivateBrowsingPattern);

    return NS_OK;
  }

  // Clear data of the origins whose prefixes will match the suffix.
  if (!strcmp(aTopic, "clear-origin-attributes-data") ||
      !strcmp(aTopic, "dom-storage:clear-origin-attributes-data")) {
    MOZ_ASSERT(XRE_IsParentProcess());

    OriginAttributesPattern pattern;
    if (!pattern.Init(nsDependentString(aData))) {
      NS_ERROR("Cannot parse origin attributes pattern");
      return NS_ERROR_FAILURE;
    }

    if (NextGenLocalStorageEnabled()) {
      Notify("session-storage:clear-origin-attributes-data",
             nsDependentString(aData));
      return NS_OK;
    }

    for (const uint32_t id : {0, 1}) {
      StorageDBChild* storageChild = StorageDBChild::GetOrCreate(id);
      if (NS_WARN_IF(!storageChild)) {
        return NS_ERROR_FAILURE;
      }

      storageChild->SendClearMatchingOriginAttributes(pattern);
    }

    Notify(aTopic, nsDependentString(aData));

    return NS_OK;
  }

  if (!strcmp(aTopic, "profile-after-change")) {
    Notify("profile-change");

    return NS_OK;
  }

  if (!strcmp(aTopic, "profile-before-change")) {
    MOZ_ASSERT(XRE_IsParentProcess());

    if (NextGenLocalStorageEnabled()) {
      return NS_OK;
    }

    for (const uint32_t id : {0, 1}) {
      if (mBackgroundThread[id]) {
        bool done = false;

        RefPtr<StorageDBThread::ShutdownRunnable> shutdownRunnable =
            new StorageDBThread::ShutdownRunnable(id, done);
        MOZ_ALWAYS_SUCCEEDS(mBackgroundThread[id]->Dispatch(
            shutdownRunnable, NS_DISPATCH_NORMAL));

        MOZ_ALWAYS_TRUE(SpinEventLoopUntil(
            "StorageObserver::Observe profile-before-change"_ns,
            [&]() { return done; }));

        mBackgroundThread[id] = nullptr;
      }
    }

    return NS_OK;
  }

#ifdef DOM_STORAGE_TESTS
  if (!strcmp(aTopic, "domstorage-test-flush-force")) {
    if (NextGenLocalStorageEnabled()) {
      return NS_OK;
    }

    for (const uint32_t id : {0, 1}) {
      StorageDBChild* storageChild = StorageDBChild::GetOrCreate(id);
      if (NS_WARN_IF(!storageChild)) {
        return NS_ERROR_FAILURE;
      }

      storageChild->SendAsyncFlush();
    }

    return NS_OK;
  }

  if (!strcmp(aTopic, "domstorage-test-flushed")) {
    if (NextGenLocalStorageEnabled()) {
      return NS_OK;
    }

    // Only used to propagate to IPC children
    Notify("test-flushed");

    return NS_OK;
  }

  if (!strcmp(aTopic, "domstorage-test-reload")) {
    if (NextGenLocalStorageEnabled()) {
      return NS_OK;
    }

    Notify("test-reload");

    return NS_OK;
  }
#endif

  NS_ERROR("Unexpected topic");
  return NS_ERROR_UNEXPECTED;
}

NS_IMETHODIMP
StorageObserver::GetName(nsACString& aName) {
  aName.AssignLiteral("StorageObserver");
  return NS_OK;
}

}  // namespace mozilla::dom