gecko-dev/dom/indexedDB/IDBCursor.h

/* -*- 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/. */

#ifndef mozilla_dom_idbcursor_h__
#define mozilla_dom_idbcursor_h__

#include "IndexedDatabase.h"
#include "js/RootingAPI.h"
#include "mozilla/Attributes.h"
#include "mozilla/dom/IDBCursorBinding.h"
#include "mozilla/dom/indexedDB/Key.h"
#include "nsCycleCollectionParticipant.h"
#include "nsWrapperCache.h"

class nsIGlobalObject;

namespace mozilla {

class ErrorResult;

namespace dom {

class IDBIndex;
class IDBObjectStore;
class IDBRequest;
class IDBTransaction;
class OwningIDBObjectStoreOrIDBIndex;

namespace indexedDB {
class BackgroundCursorChild;
}

class IDBCursor final : public nsISupports, public nsWrapperCache {
 public:
  typedef indexedDB::Key Key;
  typedef indexedDB::StructuredCloneReadInfo StructuredCloneReadInfo;

  enum Direction {
    NEXT = 0,
    NEXT_UNIQUE,
    PREV,
    PREV_UNIQUE,

    // Only needed for IPC serialization helper, should never be used in code.
    DIRECTION_INVALID
  };

 private:
  enum Type {
    Type_ObjectStore,
    Type_ObjectStoreKey,
    Type_Index,
    Type_IndexKey,
  };

  indexedDB::BackgroundCursorChild* mBackgroundActor;

  // TODO: mRequest, mSourceObjectStore and mSourceIndex could be made const if
  // Bug 1575173 is resolved. They are initialized in the constructor and never
  // modified/cleared.
  RefPtr<IDBRequest> mRequest;
  RefPtr<IDBObjectStore> mSourceObjectStore;
  RefPtr<IDBIndex> mSourceIndex;

  // mSourceObjectStore or mSourceIndex will hold this alive.
  IDBTransaction* const mTransaction;

  // These are cycle-collected!
  JS::Heap<JS::Value> mCachedKey;
  JS::Heap<JS::Value> mCachedPrimaryKey;
  JS::Heap<JS::Value> mCachedValue;

  Key mKey;
  Key mSortKey;
  Key mPrimaryKey;
  StructuredCloneReadInfo mCloneInfo;

  const Type mType;
  const Direction mDirection;

  bool mHaveCachedKey : 1;
  bool mHaveCachedPrimaryKey : 1;
  bool mHaveCachedValue : 1;
  bool mRooted : 1;
  bool mContinueCalled : 1;
  bool mHaveValue : 1;

 public:
  static already_AddRefed<IDBCursor> Create(
      indexedDB::BackgroundCursorChild* aBackgroundActor, Key aKey,
      StructuredCloneReadInfo&& aCloneInfo);

  static already_AddRefed<IDBCursor> Create(
      indexedDB::BackgroundCursorChild* aBackgroundActor, Key aKey);

  static already_AddRefed<IDBCursor> Create(
      indexedDB::BackgroundCursorChild* aBackgroundActor, Key aKey,
      Key aSortKey, Key aPrimaryKey, StructuredCloneReadInfo&& aCloneInfo);

  static already_AddRefed<IDBCursor> Create(
      indexedDB::BackgroundCursorChild* aBackgroundActor, Key aKey,
      Key aSortKey, Key aPrimaryKey);

  static Direction ConvertDirection(IDBCursorDirection aDirection);

  void AssertIsOnOwningThread() const
#ifdef DEBUG
      ;
#else
  {
  }
#endif

  nsIGlobalObject* GetParentObject() const;

  void GetSource(OwningIDBObjectStoreOrIDBIndex& aSource) const;

  IDBCursorDirection GetDirection() const;

  void GetKey(JSContext* aCx, JS::MutableHandle<JS::Value> aResult,
              ErrorResult& aRv);

  void GetPrimaryKey(JSContext* aCx, JS::MutableHandle<JS::Value> aResult,
                     ErrorResult& aRv);

  void GetValue(JSContext* aCx, JS::MutableHandle<JS::Value> aResult,
                ErrorResult& aRv);

  void Continue(JSContext* aCx, JS::Handle<JS::Value> aKey, ErrorResult& aRv);

  void ContinuePrimaryKey(JSContext* aCx, JS::Handle<JS::Value> aKey,
                          JS::Handle<JS::Value> aPrimaryKey, ErrorResult& aRv);

  void Advance(uint32_t aCount, ErrorResult& aRv);

  already_AddRefed<IDBRequest> Update(JSContext* aCx,
                                      JS::Handle<JS::Value> aValue,
                                      ErrorResult& aRv);

  already_AddRefed<IDBRequest> Delete(JSContext* aCx, ErrorResult& aRv);

  void Reset();

  void Reset(Key&& aKey, StructuredCloneReadInfo&& aValue);

  void Reset(Key&& aKey);

  void Reset(Key&& aKey, Key&& aSortKey, Key&& aPrimaryKey,
             StructuredCloneReadInfo&& aValue);

  void Reset(Key&& aKey, Key&& aSortKey, Key&& aPrimaryKey);

  void ClearBackgroundActor() {
    AssertIsOnOwningThread();

    mBackgroundActor = nullptr;
  }

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(IDBCursor)

  // nsWrapperCache
  virtual JSObject* WrapObject(JSContext* aCx,
                               JS::Handle<JSObject*> aGivenProto) override;

 private:
  IDBCursor(Type aType, indexedDB::BackgroundCursorChild* aBackgroundActor,
            Key aKey);

  ~IDBCursor();

  // Checks if this is a locale aware cursor (ie. the index's sortKey is unset)
  bool IsLocaleAware() const;

  void DropJSObjects();

  bool IsSourceDeleted() const;
};

}  // namespace dom
}  // namespace mozilla

#endif  // mozilla_dom_idbcursor_h__