gecko-dev/dom/events/DataTransferItemList.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_DataTransferItemList_h
#define mozilla_dom_DataTransferItemList_h

#include "mozilla/dom/DataTransfer.h"
#include "mozilla/dom/DataTransferItem.h"
#include "mozilla/dom/FileList.h"

namespace mozilla {
namespace dom {

class DataTransferItem;

class DataTransferItemList final : public nsISupports, public nsWrapperCache {
 public:
  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DataTransferItemList);

  explicit DataTransferItemList(DataTransfer* aDataTransfer)
      : mDataTransfer(aDataTransfer) {
    MOZ_ASSERT(aDataTransfer);
    // We always allocate an index 0 in our DataTransferItemList. This is done
    // in order to maintain the invariants according to the spec. Mainly, within
    // the spec's list, there is intended to be a single copy of each mime type,
    // for string typed items. File typed items are allowed to have duplicates.
    // In the old moz* system, this was modeled by having multiple indexes, each
    // of which was independent. Files were fetched from all indexes, but
    // strings were only fetched from the first index. In order to maintain this
    // correlation and avoid breaking code with the new changes, index 0 is now
    // always present and used to store strings, and all file items are given
    // their own index starting at index 1.
    mIndexedItems.SetLength(1);
  }

  already_AddRefed<DataTransferItemList> Clone(
      DataTransfer* aDataTransfer) const;

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

  uint32_t Length() const { return mItems.Length(); };

  DataTransferItem* Add(const nsAString& aData, const nsAString& aType,
                        nsIPrincipal& aSubjectPrincipal, ErrorResult& rv);
  DataTransferItem* Add(File& aData, nsIPrincipal& aSubjectPrincipal,
                        ErrorResult& aRv);

  void Remove(uint32_t aIndex, nsIPrincipal& aSubjectPrincipal,
              ErrorResult& aRv);

  DataTransferItem* IndexedGetter(uint32_t aIndex, bool& aFound) const;

  DataTransfer* GetParentObject() const { return mDataTransfer; }

  void Clear(nsIPrincipal& aSubjectPrincipal, ErrorResult& aRv);

  already_AddRefed<DataTransferItem> SetDataWithPrincipal(
      const nsAString& aType, nsIVariant* aData, uint32_t aIndex,
      nsIPrincipal* aPrincipal, bool aInsertOnly, bool aHidden,
      ErrorResult& aRv);

  already_AddRefed<FileList> Files(nsIPrincipal* aPrincipal);

  // Moz-style helper methods for interacting with the stored data
  void MozRemoveByTypeAt(const nsAString& aType, uint32_t aIndex,
                         nsIPrincipal& aSubjectPrincipal, ErrorResult& aRv);
  DataTransferItem* MozItemByTypeAt(const nsAString& aType, uint32_t aIndex);
  const nsTArray<RefPtr<DataTransferItem>>* MozItemsAt(uint32_t aIndex);
  uint32_t MozItemCount() const;

  // Causes everything in indexes above 0 to shift down one index.
  void PopIndexZero();

  // Delete every item in the DataTransferItemList, without checking for
  // permissions or read-only status (for internal use only).
  void ClearAllItems();

 private:
  void ClearDataHelper(DataTransferItem* aItem, uint32_t aIndexHint,
                       uint32_t aMozOffsetHint, nsIPrincipal& aSubjectPrincipal,
                       ErrorResult& aRv);
  DataTransferItem* AppendNewItem(uint32_t aIndex, const nsAString& aType,
                                  nsIVariant* aData, nsIPrincipal* aPrincipal,
                                  bool aHidden);
  void RegenerateFiles();
  void GenerateFiles(FileList* aFiles, nsIPrincipal* aFilesPrincipal);

  ~DataTransferItemList() {}

  RefPtr<DataTransfer> mDataTransfer;
  RefPtr<FileList> mFiles;
  // The principal for which mFiles is cached
  nsCOMPtr<nsIPrincipal> mFilesPrincipal;
  // mItems is the list of items that corresponds to the spec concept of a
  // DataTransferItemList.  That is, this is the thing the spec's indexed getter
  // operates on.  The items in here are a subset of the items present in the
  // arrays that live in mIndexedItems.
  nsTArray<RefPtr<DataTransferItem>> mItems;
  // mIndexedItems represents all our items.  For any given index, all items at
  // that index have different types in the GetType() sense.  That means that
  // representing multiple items with the same type (e.g. multiple files)
  // requires using multiple indices.
  //
  // There is always a (possibly empty) list of items at index 0, so
  // mIndexedItems.Length() >= 1 at all times.
  nsTArray<nsTArray<RefPtr<DataTransferItem>>> mIndexedItems;
};

}  // namespace dom
}  // namespace mozilla

#endif  // mozilla_dom_DataTransferItemList_h