tor-browser

The Tor Browser
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JoinNodesTransaction.h (3622B)

      1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* This Source Code Form is subject to the terms of the Mozilla Public
      3 * License, v. 2.0. If a copy of the MPL was not distributed with this
      4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      5 
      6 #ifndef JoinNodesTransaction_h
      7 #define JoinNodesTransaction_h
      8 
      9 #include "EditTransactionBase.h"  // for EditTransactionBase, etc.
     10 
     11 #include "EditorDOMPoint.h"  // for EditorDOMPoint, etc.
     12 #include "EditorForwards.h"
     13 
     14 #include "nsCOMPtr.h"  // for nsCOMPtr
     15 #include "nsCycleCollectionParticipant.h"
     16 #include "nsID.h"    // for REFNSIID
     17 #include "nscore.h"  // for NS_IMETHOD
     18 
     19 class nsIContent;
     20 class nsINode;
     21 
     22 namespace mozilla {
     23 
     24 /**
     25 * A transaction that joins two nodes E1 (left node) and E2 (right node) into a
     26 * single node E.  The children of E are the children of E1 followed by the
     27 * children of E2.  After DoTransaction() and RedoTransaction(), E1 is removed
     28 * from the content tree and E2 remains.
     29 */
     30 class JoinNodesTransaction final : public EditTransactionBase {
     31 protected:
     32  JoinNodesTransaction(HTMLEditor& aHTMLEditor, nsIContent& aLeftContent,
     33                       nsIContent& aRightContent);
     34 
     35 public:
     36  /**
     37   * Creates a join node transaction.  This returns nullptr if cannot join the
     38   * nodes.
     39   *
     40   * @param aHTMLEditor     The provider of core editing operations.
     41   * @param aLeftContent    The first of two nodes to join.
     42   * @param aRightContent   The second of two nodes to join.
     43   */
     44  static already_AddRefed<JoinNodesTransaction> MaybeCreate(
     45      HTMLEditor& aHTMLEditor, nsIContent& aLeftContent,
     46      nsIContent& aRightContent);
     47 
     48  /**
     49   * CanDoIt() returns true if there are enough members and can join or
     50   * restore the nodes.  Otherwise, false.
     51   */
     52  bool CanDoIt() const;
     53 
     54  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(JoinNodesTransaction,
     55                                           EditTransactionBase)
     56  NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override;
     57 
     58  NS_DECL_EDITTRANSACTIONBASE
     59  NS_DECL_EDITTRANSACTIONBASE_GETASMETHODS_OVERRIDE(JoinNodesTransaction)
     60 
     61  MOZ_CAN_RUN_SCRIPT NS_IMETHOD RedoTransaction() override;
     62 
     63  /**
     64   * GetExistingContent() and GetRemovedContent() never returns nullptr
     65   * unless the cycle collector clears them out.
     66   */
     67  nsIContent* GetExistingContent() const { return mKeepingContent; }
     68  nsIContent* GetRemovedContent() const { return mRemovedContent; }
     69  nsINode* GetParentNode() const { return mParentNode; }
     70 
     71  template <typename EditorDOMPointType>
     72  EditorDOMPointType CreateJoinedPoint() const {
     73    if (MOZ_UNLIKELY(!mKeepingContent)) {
     74      return EditorDOMPointType();
     75    }
     76    return EditorDOMPointType(
     77        mKeepingContent, std::min(mJoinedOffset, mKeepingContent->Length()));
     78  }
     79 
     80  friend std::ostream& operator<<(std::ostream& aStream,
     81                                  const JoinNodesTransaction& aTransaction);
     82 
     83 protected:
     84  virtual ~JoinNodesTransaction() = default;
     85 
     86  enum class RedoingTransaction { No, Yes };
     87  MOZ_CAN_RUN_SCRIPT nsresult DoTransactionInternal(RedoingTransaction);
     88 
     89  RefPtr<HTMLEditor> mHTMLEditor;
     90 
     91  // The original parent of the left/right nodes.
     92  nsCOMPtr<nsINode> mParentNode;
     93 
     94  // Removed content after joined.
     95  nsCOMPtr<nsIContent> mRemovedContent;
     96 
     97  // The keeping content node which contains ex-children of mRemovedContent.
     98  nsCOMPtr<nsIContent> mKeepingContent;
     99 
    100  // Offset where the original first content is in mKeepingContent after
    101  // doing or redoing.
    102  uint32_t mJoinedOffset = 0u;
    103 };
    104 
    105 }  // namespace mozilla
    106 
    107 #endif  // #ifndef JoinNodesTransaction_h