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// SPDX-FileCopyrightText: Copyright (c) Kitware Inc.
// SPDX-FileCopyrightText: Copyright (c) Sandia Corporation
// SPDX-License-Identifier: BSD-3-Clause
#ifndef pqPythonUndoCommand_h
#define pqPythonUndoCommand_h
#include "pqPythonModule.h"
#include <QTextEdit>
#include <QUndoCommand>
#include <functional>
#include <iostream>
#include <stack>
#include <vector>
class pqPythonSyntaxHighlighter;
/**
* @struct PythonTextHistory
* @brief Data structure that contains information to perform the undo
* and redo operations.
*
* @details This structure is part of the public headers as other
* might need to instantiate and pass it to the \ref pqPythonUndoCommand.
*/
struct pqPythonTextHistoryEntry
{
pqPythonTextHistoryEntry() = default;
pqPythonTextHistoryEntry(const QString& txt, const std::int32_t cursorPos)
: content(txt)
, cursorPosition(cursorPos)
{
}
/**
* @brief The raw text
*/
QString content = "";
/**
* @brief The absolute cursor position within pqPythonUndoCommand::Text
*/
std::int32_t cursorPosition = -1;
/**
* @brief Returns true is the entry is empty
*/
bool isEmpty() const noexcept { return cursorPosition == -1; }
};
/**
* @class pqPythonUndoCommand
* @brief The python text editor undo/redo command
* @details The \ref pqPythonUndoCommand models the undo/redo framework needed for QUndoStack.
* The actual storage of the \ref PythonTextHistory is external to the command: this avoids
* duplicating entries.
*/
class PQPYTHON_EXPORT pqPythonUndoCommand : public QUndoCommand
{
public:
/**
* @brief Construct an undo command
*/
pqPythonUndoCommand(QTextEdit& text, pqPythonSyntaxHighlighter* highlighter,
pqPythonTextHistoryEntry& lastHistoryEntry,
const pqPythonTextHistoryEntry&& currentHistoryEntry);
/**
* @brief Overriden function that performs the undo
*/
void undo() override;
/**
* @brief Overriden function that performs the redo
*/
void redo() override;
/**
* @brief Returns the current history entry
*/
const pqPythonTextHistoryEntry& getCurrentHistoryEntry() const
{
return this->CurrentHistoryEntry;
}
private:
/**
* @brief Utility function that mutates the \ref text
* using the given history value \ref h.
*/
void swapImpl(const pqPythonTextHistoryEntry& h);
/// @brief The text to do the undo/redo on
QTextEdit& Text;
pqPythonSyntaxHighlighter* Highlighter;
/**
* @brief The last history entry in the text
* @details This is a direct reference to the history entry
* contained in the text. This is being modified when performing
* the undo function.
*
* If we don't modify the current history entry in the next
* when performing an undo, the overall undo stack is not
* what we expect it to be. Let's take the following commands:
* [enter 1 ... enter 2 ... undo ... enter 3 ... undo]
* Without modifying the \ref TextLastHystoryEntry we would get
* 1 -> 12 -> 1 -> 13 -> 12, which is wrong.
* This problem arises from the fact that the QTextEdit doesn't keep
* its last state in memory.
*/
pqPythonTextHistoryEntry& TextLastHystoryEntry;
const pqPythonTextHistoryEntry LastHistoryEntry;
const pqPythonTextHistoryEntry CurrentHistoryEntry;
};
#endif // pqPythonUndoCommand_h
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