gecko-dev/editor/libeditor/DeleteTextTransaction.h
Masayuki Nakano 2c93600238 Bug 1797247 - part 1: Add delete transaction classes to use build time type checks r=m_kato
First, `EditorBase::CreateTransactionForDeleteSelection` returns an instance of
`EditAggregateTransaction`. It's a base class of `PlaceholderTransaction` and
`DeleteRangeTransaction` but it's also a concrete class.  However, it's too
generic.  Therefore, this patch creates `DeleteMultipleRangesTransaction` which
is a simple sub-class of it, and makes `EditAggregateTransaction` be an abstract
class.  Then, add `AddChild` methods to each concrete class to restrict the
type of child transactions.

Next, `DeleteRangeTransaction` contains only `DeleteNodeTransaction` and
`DeleteTextTransaction`.  Therefore, once they have a common base class,
we can check the type easier.  Therefore, this patch also adds
`DeleteContentTransactionBase` and
`EditorBase::CreateTransactionForCollapsedRange` becomes clearer what it
returns.

With these changes, `DeleteRangeTransaction` obviously contains only
`DeleteContentTransactionBase`, `DeleteMultipleRangesTransaction` contains only
`DeleteRangeTransaction`, `DeleteNodeTransaction` and `DeleteTextTransaction`.
And they are guaranteed at build time (at least from outside the classes).
***
fix

Differential Revision: https://phabricator.services.mozilla.com/D169038
2023-02-15 22:17:17 +00:00

100 lines
3.3 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 DeleteTextTransaction_h
#define DeleteTextTransaction_h
#include "DeleteContentTransactionBase.h"
#include "EditorForwards.h"
#include "mozilla/dom/Text.h"
#include "nsCOMPtr.h"
#include "nsCycleCollectionParticipant.h"
#include "nsID.h"
#include "nsString.h"
#include "nscore.h"
namespace mozilla {
/**
* A transaction that removes text from a content node.
*/
class DeleteTextTransaction final : public DeleteContentTransactionBase {
protected:
DeleteTextTransaction(EditorBase& aEditorBase, dom::Text& aTextNode,
uint32_t aOffset, uint32_t aLengthToDelete);
public:
/**
* Creates a delete text transaction to remove given range. This returns
* nullptr if it cannot modify the text node.
*
* @param aEditorBase The provider of basic editing operations.
* @param aTextNode The content node to remove text from.
* @param aOffset The location in aElement to begin the deletion.
* @param aLenthToDelete The length to delete.
*/
static already_AddRefed<DeleteTextTransaction> MaybeCreate(
EditorBase& aEditorBase, dom::Text& aTextNode, uint32_t aOffset,
uint32_t aLengthToDelete);
/**
* Creates a delete text transaction to remove a previous or next character.
* Those methods MAY return nullptr.
*
* @param aEditorBase The provider of basic editing operations.
* @param aTextNode The content node to remove text from.
* @param aOffset The location in aElement to begin the deletion.
*/
static already_AddRefed<DeleteTextTransaction>
MaybeCreateForPreviousCharacter(EditorBase& aEditorBase, dom::Text& aTextNode,
uint32_t aOffset);
static already_AddRefed<DeleteTextTransaction> MaybeCreateForNextCharacter(
EditorBase& aEditorBase, dom::Text& aTextNode, uint32_t aOffset);
/**
* CanDoIt() returns true if there are enough members and can modify the
* text. Otherwise, false.
*/
bool CanDoIt() const;
NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DeleteTextTransaction,
DeleteContentTransactionBase)
NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override;
NS_DECL_EDITTRANSACTIONBASE
NS_DECL_EDITTRANSACTIONBASE_GETASMETHODS_OVERRIDE(DeleteTextTransaction)
MOZ_CAN_RUN_SCRIPT NS_IMETHOD RedoTransaction() final;
EditorDOMPoint SuggestPointToPutCaret() const final;
dom::Text* GetText() const { return mTextNode; }
uint32_t Offset() const { return mOffset; }
uint32_t LengthToDelete() const { return mLengthToDelete; }
friend std::ostream& operator<<(std::ostream& aStream,
const DeleteTextTransaction& aTransaction);
protected:
// The CharacterData node to operate upon.
RefPtr<dom::Text> mTextNode;
// The offset into mTextNode where the deletion is to take place.
uint32_t mOffset;
// The length to delete.
uint32_t mLengthToDelete;
// The text that was deleted.
nsString mDeletedText;
};
} // namespace mozilla
#endif // #ifndef DeleteTextTransaction_h