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/* -*- 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_DataTransfer_h
#define mozilla_dom_DataTransfer_h

#include "nsString.h"
#include "nsTArray.h"
#include "nsIVariant.h"
#include "nsIPrincipal.h"
#include "nsIDOMDataTransfer.h"
#include "nsIDOMElement.h"
#include "nsIDragService.h"
#include "nsCycleCollectionParticipant.h"

#include "mozilla/Attributes.h"
#include "mozilla/EventForwards.h"
#include "mozilla/dom/BindingDeclarations.h"
#include "mozilla/dom/File.h"

class nsINode;
class nsITransferable;
class nsILoadContext;

namespace mozilla {

class EventStateManager;

namespace dom {

class DataTransferItem;
class DataTransferItemList;
class DOMStringList;
class Element;
class FileList;
class Promise;
template <typename T>
class Optional;

#define NS_DATATRANSFER_IID                          \
  {                                                  \
    0x6c5f90d1, 0xa886, 0x42c8, {                    \
      0x85, 0x06, 0x10, 0xbe, 0x5c, 0x0d, 0xc6, 0x77 \
    }                                                \
  }

class DataTransfer final : public nsIDOMDataTransfer, public nsWrapperCache {
 public:
  NS_DECLARE_STATIC_IID_ACCESSOR(NS_DATATRANSFER_IID)

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_NSIDOMDATATRANSFER

  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DataTransfer)

  friend class mozilla::EventStateManager;

  static DataTransfer* Cast(nsIDOMDataTransfer* aArg) {
    return static_cast<DataTransfer*>(aArg);
  }

  /// An enum which represents which "Drag Data Store Mode" the DataTransfer is
  /// in according to the spec.
  enum class Mode : uint8_t {
    ReadWrite,
    ReadOnly,
    Protected,
  };

 protected:
  // hide the default constructor
  DataTransfer();

  // this constructor is used only by the Clone method to copy the fields as
  // needed to a new data transfer.
  // NOTE: Do not call this method directly.
  DataTransfer(nsISupports* aParent, EventMessage aEventMessage,
               const uint32_t aEffectAllowed, bool aCursorState,
               bool aIsExternal, bool aUserCancelled,
               bool aIsCrossDomainSubFrameDrop, int32_t aClipboardType,
               DataTransferItemList* aItems, Element* aDragImage,
               uint32_t aDragImageX, uint32_t aDragImageY);

  ~DataTransfer();

  static const char sEffects[8][9];

 public:
  // Constructor for DataTransfer.
  //
  // aIsExternal must only be true when used to create a dataTransfer for a
  // paste or a drag that was started without using a data transfer. The
  // latter will occur when an external drag occurs, that is, a drag where the
  // source is another application, or a drag is started by calling the drag
  // service directly. For clipboard operations, aClipboardType indicates
  // which clipboard to use, from nsIClipboard, or -1 for non-clipboard
  // operations, or if access to the system clipboard should not be allowed.
  DataTransfer(nsISupports* aParent, EventMessage aEventMessage,
               bool aIsExternal, int32_t aClipboardType);

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

  nsISupports* GetParentObject() const { return mParent; }

  void SetParentObject(nsISupports* aNewParent) {
    MOZ_ASSERT(aNewParent);
    // Setting the parent after we've been wrapped is pointless, so
    // make sure we aren't wrapped yet.
    MOZ_ASSERT(!GetWrapperPreserveColor());
    mParent = aNewParent;
  }

  static already_AddRefed<DataTransfer> Constructor(const GlobalObject& aGlobal,
                                                    const nsAString& aEventType,
                                                    bool aIsExternal,
                                                    ErrorResult& aRv);

  void GetDropEffect(nsString& aDropEffect) {
    aDropEffect.AssignASCII(sEffects[mDropEffect]);
  }

  void GetEffectAllowed(nsString& aEffectAllowed) {
    if (mEffectAllowed == nsIDragService::DRAGDROP_ACTION_UNINITIALIZED) {
      aEffectAllowed.AssignLiteral("uninitialized");
    } else {
      aEffectAllowed.AssignASCII(sEffects[mEffectAllowed]);
    }
  }

  void SetDragImage(Element& aElement, int32_t aX, int32_t aY);
  void UpdateDragImage(Element& aElement, int32_t aX, int32_t aY);

  void GetTypes(nsTArray<nsString>& aTypes, CallerType aCallerType) const;

  void GetData(const nsAString& aFormat, nsAString& aData,
               nsIPrincipal& aSubjectPrincipal, ErrorResult& aRv);

  void SetData(const nsAString& aFormat, const nsAString& aData,
               nsIPrincipal& aSubjectPrincipal, ErrorResult& aRv);

  void ClearData(const mozilla::dom::Optional<nsAString>& aFormat,
                 nsIPrincipal& aSubjectPrincipal, mozilla::ErrorResult& aRv);

  already_AddRefed<FileList> GetFiles(nsIPrincipal& aSubjectPrincipal,
                                      mozilla::ErrorResult& aRv);

  already_AddRefed<Promise> GetFilesAndDirectories(
      nsIPrincipal& aSubjectPrincipal, mozilla::ErrorResult& aRv);

  already_AddRefed<Promise> GetFiles(bool aRecursiveFlag,
                                     nsIPrincipal& aSubjectPrincipal,
                                     ErrorResult& aRv);

  void AddElement(Element& aElement, mozilla::ErrorResult& aRv);

  uint32_t MozItemCount() const;

  void GetMozCursor(nsString& aCursor) {
    if (mCursorState) {
      aCursor.AssignLiteral("default");
    } else {
      aCursor.AssignLiteral("auto");
    }
  }

  already_AddRefed<DOMStringList> MozTypesAt(uint32_t aIndex,
                                             CallerType aCallerType,
                                             mozilla::ErrorResult& aRv) const;

  void MozClearDataAt(const nsAString& aFormat, uint32_t aIndex,
                      nsIPrincipal& aSubjectPrincipal,
                      mozilla::ErrorResult& aRv);

  void MozSetDataAt(JSContext* aCx, const nsAString& aFormat,
                    JS::Handle<JS::Value> aData, uint32_t aIndex,
                    nsIPrincipal& aSubjectPrincipal, mozilla::ErrorResult& aRv);

  void MozGetDataAt(JSContext* aCx, const nsAString& aFormat, uint32_t aIndex,
                    JS::MutableHandle<JS::Value> aRetval,
                    nsIPrincipal& aSubjectPrincipal, mozilla::ErrorResult& aRv);

  bool MozUserCancelled() const { return mUserCancelled; }

  already_AddRefed<nsINode> GetMozSourceNode();

  void GetMozTriggeringPrincipalURISpec(nsAString& aPrincipalURISpec);

  mozilla::dom::Element* GetDragTarget() const { return mDragTarget; }

  nsresult GetDataAtNoSecurityCheck(const nsAString& aFormat, uint32_t aIndex,
                                    nsIVariant** aData);

  DataTransferItemList* Items() const { return mItems; }

  // Returns the current "Drag Data Store Mode" of the DataTransfer. This
  // determines what modifications may be performed on the DataTransfer, and
  // what data may be read from it.
  Mode GetMode() const { return mMode; }
  void SetMode(Mode aMode);

  // Helper method. Is true if the DataTransfer's mode is ReadOnly or Protected,
  // which means that the DataTransfer cannot be modified.
  bool IsReadOnly() const { return mMode != Mode::ReadWrite; }
  // Helper method. Is true if the DataTransfer's mode is Protected, which means
  // that DataTransfer type information may be read, but data may not be.
  bool IsProtected() const { return mMode == Mode::Protected; }

  int32_t ClipboardType() const { return mClipboardType; }
  EventMessage GetEventMessage() const { return mEventMessage; }
  bool IsCrossDomainSubFrameDrop() const { return mIsCrossDomainSubFrameDrop; }

  // converts the data into an array of nsITransferable objects to be used for
  // drag and drop or clipboard operations.
  already_AddRefed<nsIArray> GetTransferables(nsIDOMNode* aDragTarget);

  already_AddRefed<nsIArray> GetTransferables(nsILoadContext* aLoadContext);

  // converts the data for a single item at aIndex into an nsITransferable
  // object.
  already_AddRefed<nsITransferable> GetTransferable(
      uint32_t aIndex, nsILoadContext* aLoadContext);

  // converts the data in the variant to an nsISupportString if possible or
  // an nsISupports or null otherwise.
  bool ConvertFromVariant(nsIVariant* aVariant, nsISupports** aSupports,
                          uint32_t* aLength) const;

  // Disconnects the DataTransfer from the Drag Data Store. If the
  // dom.dataTransfer.disconnect pref is enabled, this will clear the
  // DataTransfer and set it to the `Protected` state, otherwise this method is
  // a no-op.
  void Disconnect();

  // clears all of the data
  void ClearAll();

  // Similar to SetData except also specifies the principal to store.
  // aData may be null when called from CacheExternalDragFormats or
  // CacheExternalClipboardFormats.
  nsresult SetDataWithPrincipal(const nsAString& aFormat, nsIVariant* aData,
                                uint32_t aIndex, nsIPrincipal* aPrincipal,
                                bool aHidden = false);

  // Variation of SetDataWithPrincipal with handles extracting
  // kCustomTypesMime data into separate types.
  void SetDataWithPrincipalFromOtherProcess(const nsAString& aFormat,
                                            nsIVariant* aData, uint32_t aIndex,
                                            nsIPrincipal* aPrincipal,
                                            bool aHidden);

  // returns a weak reference to the drag image
  Element* GetDragImage(int32_t* aX, int32_t* aY) const {
    *aX = mDragImageX;
    *aY = mDragImageY;
    return mDragImage;
  }

  // This method makes a copy of the DataTransfer object, with a few properties
  // changed, and the mode updated to reflect the correct mode for the given
  // event. This method is used during the drag operation to generate the
  // DataTransfer objects for each event after `dragstart`. Event objects will
  // lazily clone the DataTransfer stored in the DragSession (which is a clone
  // of the DataTransfer used in the `dragstart` event) when requested.
  nsresult Clone(nsISupports* aParent, EventMessage aEventMessage,
                 bool aUserCancelled, bool aIsCrossDomainSubFrameDrop,
                 DataTransfer** aResult);

  // converts some formats used for compatibility in aInFormat into aOutFormat.
  // Text and text/unicode become text/plain, and URL becomes text/uri-list
  void GetRealFormat(const nsAString& aInFormat, nsAString& aOutFormat) const;

  static bool PrincipalMaySetData(const nsAString& aFormat, nsIVariant* aData,
                                  nsIPrincipal* aPrincipal);

  // Notify the DataTransfer that the list returned from GetTypes may have
  // changed.  This can happen due to items we care about for purposes of
  // GetTypes being added or removed or changing item kinds.
  void TypesListMayHaveChanged();

  // Testing method used to emulate internal DataTransfer management.
  // NOTE: Please don't use this. See the comments in the webidl for more.
  already_AddRefed<DataTransfer> MozCloneForEvent(const nsAString& aEvent,
                                                  ErrorResult& aRv);

 protected:
  // caches text and uri-list data formats that exist in the drag service or
  // clipboard for retrieval later.
  nsresult CacheExternalData(const char* aFormat, uint32_t aIndex,
                             nsIPrincipal* aPrincipal, bool aHidden);

  // caches the formats that exist in the drag service that were added by an
  // external drag
  void CacheExternalDragFormats();

  // caches the formats that exist in the clipboard
  void CacheExternalClipboardFormats(bool aPlainTextOnly);

  FileList* GetFilesInternal(ErrorResult& aRv, nsIPrincipal* aSubjectPrincipal);
  nsresult GetDataAtInternal(const nsAString& aFormat, uint32_t aIndex,
                             nsIPrincipal* aSubjectPrincipal,
                             nsIVariant** aData);

  nsresult SetDataAtInternal(const nsAString& aFormat, nsIVariant* aData,
                             uint32_t aIndex, nsIPrincipal* aSubjectPrincipal);

  friend class ContentParent;

  void FillAllExternalData();

  void FillInExternalCustomTypes(uint32_t aIndex, nsIPrincipal* aPrincipal);

  void FillInExternalCustomTypes(nsIVariant* aData, uint32_t aIndex,
                                 nsIPrincipal* aPrincipal);

  void MozClearDataAtHelper(const nsAString& aFormat, uint32_t aIndex,
                            nsIPrincipal& aSubjectPrincipal,
                            mozilla::ErrorResult& aRv);

  nsCOMPtr<nsISupports> mParent;

  // the drop effect and effect allowed
  uint32_t mDropEffect;
  uint32_t mEffectAllowed;

  // the event message this data transfer is for. This will correspond to an
  // event->mMessage value.
  EventMessage mEventMessage;

  // Indicates the behavior of the cursor during drag operations
  bool mCursorState;

  // The current "Drag Data Store Mode" which the DataTransfer is in.
  Mode mMode;

  // true for drags started without a data transfer, for example, those from
  // another application.
  bool mIsExternal;

  // true if the user cancelled the drag. Used only for the dragend event.
  bool mUserCancelled;

  // true if this is a cross-domain drop from a subframe where access to the
  // data should be prevented
  bool mIsCrossDomainSubFrameDrop;

  // Indicates which clipboard type to use for clipboard operations. Ignored for
  // drag and drop.
  int32_t mClipboardType;

  // The items contained with the DataTransfer
  RefPtr<DataTransferItemList> mItems;

  // the target of the drag. The drag and dragend events will fire at this.
  nsCOMPtr<mozilla::dom::Element> mDragTarget;

  // the custom drag image and coordinates within the image. If mDragImage is
  // null, the default image is created from the drag target.
  nsCOMPtr<mozilla::dom::Element> mDragImage;
  uint32_t mDragImageX;
  uint32_t mDragImageY;
};

NS_DEFINE_STATIC_IID_ACCESSOR(DataTransfer, NS_DATATRANSFER_IID)

}  // namespace dom
}  // namespace mozilla

#endif /* mozilla_dom_DataTransfer_h */