/* -*- 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 "DOMStorageManager.h"
#include "DOMStorage.h"
#include "DOMStorageDBThread.h"

#include "nsIScriptSecurityManager.h"
#include "nsIEffectiveTLDService.h"

#include "nsNetUtil.h"
#include "nsNetCID.h"
#include "nsIURL.h"
#include "nsPrintfCString.h"
#include "nsXULAppAPI.h"
#include "nsThreadUtils.h"
#include "nsIObserverService.h"
#include "mozilla/Services.h"
#include "mozilla/Preferences.h"

// Only allow relatively small amounts of data since performance of
// the synchronous IO is very bad.
// We are enforcing simple per-origin quota only.
#define DEFAULT_QUOTA_LIMIT (5 * 1024)

namespace mozilla {
namespace dom {

namespace {

int32_t gQuotaLimit = DEFAULT_QUOTA_LIMIT;

} // namespace

DOMLocalStorageManager*
DOMLocalStorageManager::sSelf = nullptr;

// static
uint32_t
DOMStorageManager::GetQuota()
{
  static bool preferencesInitialized = false;
  if (!preferencesInitialized) {
    mozilla::Preferences::AddIntVarCache(&gQuotaLimit, "dom.storage.default_quota",
                                         DEFAULT_QUOTA_LIMIT);
    preferencesInitialized = true;
  }

  return gQuotaLimit * 1024; // pref is in kBs
}

void
ReverseString(const nsCSubstring& aSource, nsCSubstring& aResult)
{
  nsACString::const_iterator sourceBegin, sourceEnd;
  aSource.BeginReading(sourceBegin);
  aSource.EndReading(sourceEnd);

  aResult.SetLength(aSource.Length());
  nsACString::iterator destEnd;
  aResult.EndWriting(destEnd);

  while (sourceBegin != sourceEnd) {
    *(--destEnd) = *sourceBegin;
    ++sourceBegin;
  }
}

nsresult
CreateReversedDomain(const nsACString& aAsciiDomain,
                     nsACString& aKey)
{
  if (aAsciiDomain.IsEmpty()) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  ReverseString(aAsciiDomain, aKey);

  aKey.Append('.');
  return NS_OK;
}

bool
PrincipalsEqual(nsIPrincipal* aObjectPrincipal, nsIPrincipal* aSubjectPrincipal)
{
  if (!aSubjectPrincipal) {
    return true;
  }

  if (!aObjectPrincipal) {
    return false;
  }

  return aSubjectPrincipal->Equals(aObjectPrincipal);
}

NS_IMPL_ISUPPORTS(DOMStorageManager,
                  nsIDOMStorageManager)

DOMStorageManager::DOMStorageManager(DOMStorage::StorageType aType)
  : mCaches(8)
  , mType(aType)
  , mLowDiskSpace(false)
{
  DOMStorageObserver* observer = DOMStorageObserver::Self();
  NS_ASSERTION(observer, "No DOMStorageObserver, cannot observe private data delete notifications!");

  if (observer) {
    observer->AddSink(this);
  }
}

DOMStorageManager::~DOMStorageManager()
{
  DOMStorageObserver* observer = DOMStorageObserver::Self();
  if (observer) {
    observer->RemoveSink(this);
  }
}

namespace {

nsresult
CreateScopeKey(nsIPrincipal* aPrincipal,
               nsACString& aKey)
{
  nsCOMPtr<nsIURI> uri;
  nsresult rv = aPrincipal->GetURI(getter_AddRefs(uri));
  NS_ENSURE_SUCCESS(rv, rv);
  if (!uri) {
    return NS_ERROR_UNEXPECTED;
  }

  nsAutoCString domainScope;
  rv = uri->GetAsciiHost(domainScope);
  NS_ENSURE_SUCCESS(rv, rv);

  if (domainScope.IsEmpty()) {
    // For the file:/// protocol use the exact directory as domain.
    bool isScheme = false;
    if (NS_SUCCEEDED(uri->SchemeIs("file", &isScheme)) && isScheme) {
      nsCOMPtr<nsIURL> url = do_QueryInterface(uri, &rv);
      NS_ENSURE_SUCCESS(rv, rv);
      rv = url->GetDirectory(domainScope);
      NS_ENSURE_SUCCESS(rv, rv);
    }
  }

  nsAutoCString key;

  rv = CreateReversedDomain(domainScope, key);
  if (NS_FAILED(rv)) {
    return rv;
  }

  nsAutoCString scheme;
  rv = uri->GetScheme(scheme);
  NS_ENSURE_SUCCESS(rv, rv);

  key.Append(':');
  key.Append(scheme);

  int32_t port = NS_GetRealPort(uri);
  if (port != -1) {
    key.Append(nsPrintfCString(":%d", port));
  }

  if (!aPrincipal->GetUnknownAppId()) {
    uint32_t appId = aPrincipal->GetAppId();
    bool isInBrowserElement = aPrincipal->GetIsInBrowserElement();
    if (appId == nsIScriptSecurityManager::NO_APP_ID && !isInBrowserElement) {
      aKey.Assign(key);
      return NS_OK;
    }

    aKey.Truncate();
    aKey.AppendInt(appId);
    aKey.Append(':');
    aKey.Append(isInBrowserElement ? 't' : 'f');
    aKey.Append(':');
    aKey.Append(key);
  }

  return NS_OK;
}

nsresult
CreateQuotaDBKey(nsIPrincipal* aPrincipal,
                 nsACString& aKey)
{
  nsresult rv;

  nsAutoCString subdomainsDBKey;
  nsCOMPtr<nsIEffectiveTLDService> eTLDService(do_GetService(
    NS_EFFECTIVETLDSERVICE_CONTRACTID, &rv));
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsIURI> uri;
  rv = aPrincipal->GetURI(getter_AddRefs(uri));
  NS_ENSURE_SUCCESS(rv, rv);
  NS_ENSURE_TRUE(uri, NS_ERROR_UNEXPECTED);

  nsAutoCString eTLDplusOne;
  rv = eTLDService->GetBaseDomain(uri, 0, eTLDplusOne);
  if (NS_ERROR_INSUFFICIENT_DOMAIN_LEVELS == rv) {
    // XXX bug 357323 - what to do for localhost/file exactly?
    rv = uri->GetAsciiHost(eTLDplusOne);
  }
  NS_ENSURE_SUCCESS(rv, rv);

  CreateReversedDomain(eTLDplusOne, subdomainsDBKey);

  if (!aPrincipal->GetUnknownAppId()) {
    uint32_t appId = aPrincipal->GetAppId();
    bool isInBrowserElement = aPrincipal->GetIsInBrowserElement();
    if (appId == nsIScriptSecurityManager::NO_APP_ID && !isInBrowserElement) {
      aKey.Assign(subdomainsDBKey);
      return NS_OK;
    }

    aKey.Truncate();
    aKey.AppendInt(appId);
    aKey.Append(':');
    aKey.Append(isInBrowserElement ? 't' : 'f');
    aKey.Append(':');
    aKey.Append(subdomainsDBKey);
  }

  return NS_OK;
}

} // namespace

DOMStorageCache*
DOMStorageManager::GetCache(const nsACString& aScope) const
{
  DOMStorageCacheHashKey* entry = mCaches.GetEntry(aScope);
  if (!entry) {
    return nullptr;
  }

  return entry->cache();
}

already_AddRefed<DOMStorageUsage>
DOMStorageManager::GetScopeUsage(const nsACString& aScope)
{
  RefPtr<DOMStorageUsage> usage;
  if (mUsages.Get(aScope, &usage)) {
    return usage.forget();
  }

  usage = new DOMStorageUsage(aScope);

  if (mType == LocalStorage) {
    DOMStorageDBBridge* db = DOMStorageCache::StartDatabase();
    if (db) {
      db->AsyncGetUsage(usage);
    }
  }

  mUsages.Put(aScope, usage);

  return usage.forget();
}

already_AddRefed<DOMStorageCache>
DOMStorageManager::PutCache(const nsACString& aScope,
                            nsIPrincipal* aPrincipal)
{
  DOMStorageCacheHashKey* entry = mCaches.PutEntry(aScope);
  RefPtr<DOMStorageCache> cache = entry->cache();

  nsAutoCString quotaScope;
  CreateQuotaDBKey(aPrincipal, quotaScope);

  switch (mType) {
  case SessionStorage:
    // Lifetime handled by the manager, don't persist
    entry->HardRef();
    cache->Init(this, false, aPrincipal, quotaScope);
    break;

  case LocalStorage:
    // Lifetime handled by the cache, do persist
    cache->Init(this, true, aPrincipal, quotaScope);
    break;

  default:
    MOZ_ASSERT(false);
  }

  return cache.forget();
}

void
DOMStorageManager::DropCache(DOMStorageCache* aCache)
{
  if (!NS_IsMainThread()) {
    NS_WARNING("DOMStorageManager::DropCache called on a non-main thread, shutting down?");
  }

  mCaches.RemoveEntry(aCache->Scope());
}

nsresult
DOMStorageManager::GetStorageInternal(bool aCreate,
                                      nsIDOMWindow* aWindow,
                                      nsIPrincipal* aPrincipal,
                                      const nsAString& aDocumentURI,
                                      bool aPrivate,
                                      nsIDOMStorage** aRetval)
{
  nsresult rv;

  nsAutoCString scope;
  rv = CreateScopeKey(aPrincipal, scope);
  if (NS_FAILED(rv)) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  RefPtr<DOMStorageCache> cache = GetCache(scope);

  // Get or create a cache for the given scope
  if (!cache) {
    if (!aCreate) {
      *aRetval = nullptr;
      return NS_OK;
    }

    if (!aRetval) {
      // This is demand to just preload the cache, if the scope has
      // no data stored, bypass creation and preload of the cache.
      DOMStorageDBBridge* db = DOMStorageCache::GetDatabase();
      if (db) {
        if (!db->ShouldPreloadScope(scope)) {
          return NS_OK;
        }
      } else {
        if (scope.EqualsLiteral("knalb.:about")) {
          return NS_OK;
        }
      }
    }

    // There is always a single instance of a cache per scope
    // in a single instance of a DOM storage manager.
    cache = PutCache(scope, aPrincipal);
  } else if (mType == SessionStorage) {
    if (!cache->CheckPrincipal(aPrincipal)) {
      return NS_ERROR_DOM_SECURITY_ERR;
    }
  }

  if (aRetval) {
    nsCOMPtr<nsIDOMStorage> storage = new DOMStorage(
      aWindow, this, cache, aDocumentURI, aPrincipal, aPrivate);
    storage.forget(aRetval);
  }

  return NS_OK;
}

NS_IMETHODIMP
DOMStorageManager::PrecacheStorage(nsIPrincipal* aPrincipal)
{
  return GetStorageInternal(true, nullptr, aPrincipal, EmptyString(), false,
                            nullptr);
}

NS_IMETHODIMP
DOMStorageManager::CreateStorage(nsIDOMWindow* aWindow,
                                 nsIPrincipal* aPrincipal,
                                 const nsAString& aDocumentURI,
                                 bool aPrivate,
                                 nsIDOMStorage** aRetval)
{
  return GetStorageInternal(true, aWindow, aPrincipal, aDocumentURI, aPrivate,
                            aRetval);
}

NS_IMETHODIMP
DOMStorageManager::GetStorage(nsIDOMWindow* aWindow,
                              nsIPrincipal* aPrincipal,
                              bool aPrivate,
                              nsIDOMStorage** aRetval)
{
  return GetStorageInternal(false, aWindow, aPrincipal, EmptyString(), aPrivate,
                            aRetval);
}

NS_IMETHODIMP
DOMStorageManager::CloneStorage(nsIDOMStorage* aStorage)
{
  if (mType != SessionStorage) {
    // Cloning is supported only for sessionStorage
    return NS_ERROR_NOT_IMPLEMENTED;
  }

  RefPtr<DOMStorage> storage = static_cast<DOMStorage*>(aStorage);
  if (!storage) {
    return NS_ERROR_UNEXPECTED;
  }

  const DOMStorageCache* origCache = storage->GetCache();

  DOMStorageCache* existingCache = GetCache(origCache->Scope());
  if (existingCache) {
    // Do not replace an existing sessionStorage.
    return NS_ERROR_NOT_AVAILABLE;
  }

  // Since this manager is sessionStorage manager, PutCache hard references
  // the cache in our hashtable.
  RefPtr<DOMStorageCache> newCache = PutCache(origCache->Scope(),
                                                origCache->Principal());

  newCache->CloneFrom(origCache);
  return NS_OK;
}

NS_IMETHODIMP
DOMStorageManager::CheckStorage(nsIPrincipal* aPrincipal,
                                nsIDOMStorage* aStorage,
                                bool* aRetval)
{
  RefPtr<DOMStorage> storage = static_cast<DOMStorage*>(aStorage);
  if (!storage) {
    return NS_ERROR_UNEXPECTED;
  }

  *aRetval = false;

  if (!aPrincipal) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  nsAutoCString scope;
  nsresult rv = CreateScopeKey(aPrincipal, scope);
  if (NS_FAILED(rv)) {
    return rv;
  }

  DOMStorageCache* cache = GetCache(scope);
  if (cache != storage->GetCache()) {
    return NS_OK;
  }

  if (!storage->PrincipalEquals(aPrincipal)) {
    return NS_OK;
  }

  *aRetval = true;
  return NS_OK;
}

// Obsolete nsIDOMStorageManager methods

NS_IMETHODIMP
DOMStorageManager::GetLocalStorageForPrincipal(nsIPrincipal* aPrincipal,
                                               const nsAString& aDocumentURI,
                                               bool aPrivate,
                                               nsIDOMStorage** aRetval)
{
  if (mType != LocalStorage) {
    return NS_ERROR_UNEXPECTED;
  }

  return CreateStorage(nullptr, aPrincipal, aDocumentURI, aPrivate, aRetval);
}

void
DOMStorageManager::ClearCaches(uint32_t aUnloadFlags,
                               const nsACString& aKeyPrefix)
{
  for (auto iter = mCaches.Iter(); !iter.Done(); iter.Next()) {
    DOMStorageCache* cache = iter.Get()->cache();
    nsCString& key = const_cast<nsCString&>(cache->Scope());

    if (aKeyPrefix.IsEmpty() || StringBeginsWith(key, aKeyPrefix)) {
      cache->UnloadItems(aUnloadFlags);
    }
  }
}

nsresult
DOMStorageManager::Observe(const char* aTopic, const nsACString& aScopePrefix)
{
  // Clear everything, caches + database
  if (!strcmp(aTopic, "cookie-cleared") ||
      !strcmp(aTopic, "extension:purge-localStorage-caches")) {
    ClearCaches(DOMStorageCache::kUnloadComplete, EmptyCString());
    return NS_OK;
  }

  // Clear from caches everything that has been stored
  // while in session-only mode
  if (!strcmp(aTopic, "session-only-cleared")) {
    ClearCaches(DOMStorageCache::kUnloadSession, aScopePrefix);
    return NS_OK;
  }

  // Clear everything (including so and pb data) from caches and database
  // for the gived domain and subdomains.
  if (!strcmp(aTopic, "domain-data-cleared")) {
    ClearCaches(DOMStorageCache::kUnloadComplete, aScopePrefix);
    return NS_OK;
  }

  // Clear all private-browsing caches
  if (!strcmp(aTopic, "private-browsing-data-cleared")) {
    ClearCaches(DOMStorageCache::kUnloadPrivate, EmptyCString());
    return NS_OK;
  }

  // Clear localStorage data beloging to an app.
  if (!strcmp(aTopic, "app-data-cleared")) {

    // sessionStorage is expected to stay
    if (mType == SessionStorage) {
      return NS_OK;
    }

    ClearCaches(DOMStorageCache::kUnloadComplete, aScopePrefix);
    return NS_OK;
  }

  if (!strcmp(aTopic, "profile-change")) {
    // For case caches are still referenced - clear them completely
    ClearCaches(DOMStorageCache::kUnloadComplete, EmptyCString());
    mCaches.Clear();
    return NS_OK;
  }

  if (!strcmp(aTopic, "low-disk-space")) {
    if (mType == LocalStorage) {
      mLowDiskSpace = true;
    }

    return NS_OK;
  }

  if (!strcmp(aTopic, "no-low-disk-space")) {
    if (mType == LocalStorage) {
      mLowDiskSpace = false;
    }

    return NS_OK;
  }

#ifdef DOM_STORAGE_TESTS
  if (!strcmp(aTopic, "test-reload")) {
    if (mType != LocalStorage) {
      return NS_OK;
    }

    // This immediately completely reloads all caches from the database.
    ClearCaches(DOMStorageCache::kTestReload, EmptyCString());
    return NS_OK;
  }

  if (!strcmp(aTopic, "test-flushed")) {
    if (!XRE_IsParentProcess()) {
      nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
      if (obs) {
        obs->NotifyObservers(nullptr, "domstorage-test-flushed", nullptr);
      }
    }

    return NS_OK;
  }
#endif

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

// DOMLocalStorageManager

DOMLocalStorageManager::DOMLocalStorageManager()
  : DOMStorageManager(LocalStorage)
{
  NS_ASSERTION(!sSelf, "Somebody is trying to do_CreateInstance(\"@mozilla/dom/localStorage-manager;1\"");
  sSelf = this;

  if (!XRE_IsParentProcess()) {
    // Do this only on the child process.  The thread IPC bridge
    // is also used to communicate chrome observer notifications.
    // Note: must be called after we set sSelf
    DOMStorageCache::StartDatabase();
  }
}

DOMLocalStorageManager::~DOMLocalStorageManager()
{
  sSelf = nullptr;
}

DOMLocalStorageManager*
DOMLocalStorageManager::Ensure()
{
  if (sSelf) {
    return sSelf;
  }

  // Cause sSelf to be populated.
  nsCOMPtr<nsIDOMStorageManager> initializer =
    do_GetService("@mozilla.org/dom/localStorage-manager;1");
  MOZ_ASSERT(sSelf, "Didn't initialize?");

  return sSelf;
}

// DOMSessionStorageManager

DOMSessionStorageManager::DOMSessionStorageManager()
  : DOMStorageManager(SessionStorage)
{
  if (!XRE_IsParentProcess()) {
    // Do this only on the child process.  The thread IPC bridge
    // is also used to communicate chrome observer notifications.
    DOMStorageCache::StartDatabase();
  }
}

} // namespace dom
} // namespace mozilla