mirror of https://github.com/ppy/osu
135 lines
4.3 KiB
C#
135 lines
4.3 KiB
C#
// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
|
|
// See the LICENCE file in the repository root for full licence text.
|
|
|
|
using System;
|
|
using System.Collections.Generic;
|
|
using System.IO;
|
|
using System.Linq;
|
|
using osu.Framework.Bindables;
|
|
using osu.Framework.Extensions;
|
|
|
|
namespace osu.Game.Screens.Edit
|
|
{
|
|
/// <summary>
|
|
/// Tracks changes to the <see cref="Editor"/>.
|
|
/// </summary>
|
|
public abstract partial class EditorChangeHandler : TransactionalCommitComponent, IEditorChangeHandler
|
|
{
|
|
public readonly Bindable<bool> CanUndo = new Bindable<bool>();
|
|
public readonly Bindable<bool> CanRedo = new Bindable<bool>();
|
|
|
|
public event Action? OnStateChange;
|
|
|
|
private readonly List<byte[]> savedStates = new List<byte[]>();
|
|
|
|
private int currentState = -1;
|
|
|
|
/// <summary>
|
|
/// A SHA-2 hash representing the current visible editor state.
|
|
/// </summary>
|
|
public string CurrentStateHash
|
|
{
|
|
get
|
|
{
|
|
ensureStateSaved();
|
|
|
|
using (var stream = new MemoryStream(savedStates[currentState]))
|
|
return stream.ComputeSHA2Hash();
|
|
}
|
|
}
|
|
|
|
private bool isRestoring;
|
|
|
|
public const int MAX_SAVED_STATES = 50;
|
|
|
|
public override void BeginChange()
|
|
{
|
|
ensureStateSaved();
|
|
|
|
base.BeginChange();
|
|
}
|
|
|
|
private void ensureStateSaved()
|
|
{
|
|
if (savedStates.Count == 0)
|
|
SaveState();
|
|
}
|
|
|
|
protected override void UpdateState()
|
|
{
|
|
if (isRestoring)
|
|
return;
|
|
|
|
using (var stream = new MemoryStream())
|
|
{
|
|
WriteCurrentStateToStream(stream);
|
|
byte[] newState = stream.ToArray();
|
|
|
|
// if the previous state is binary equal we don't need to push a new one, unless this is the initial state.
|
|
if (savedStates.Count > 0 && newState.SequenceEqual(savedStates[currentState])) return;
|
|
|
|
if (currentState < savedStates.Count - 1)
|
|
savedStates.RemoveRange(currentState + 1, savedStates.Count - currentState - 1);
|
|
|
|
if (savedStates.Count > MAX_SAVED_STATES)
|
|
savedStates.RemoveAt(0);
|
|
|
|
savedStates.Add(newState);
|
|
|
|
currentState = savedStates.Count - 1;
|
|
|
|
OnStateChange?.Invoke();
|
|
updateBindables();
|
|
}
|
|
}
|
|
|
|
/// <summary>
|
|
/// Restores an older or newer state.
|
|
/// </summary>
|
|
/// <param name="direction">The direction to restore in. If less than 0, an older state will be used. If greater than 0, a newer state will be used.</param>
|
|
public void RestoreState(int direction)
|
|
{
|
|
if (TransactionActive)
|
|
return;
|
|
|
|
if (savedStates.Count == 0)
|
|
return;
|
|
|
|
int newState = Math.Clamp(currentState + direction, 0, savedStates.Count - 1);
|
|
if (currentState == newState)
|
|
return;
|
|
|
|
isRestoring = true;
|
|
|
|
ApplyStateChange(savedStates[currentState], savedStates[newState]);
|
|
|
|
currentState = newState;
|
|
|
|
isRestoring = false;
|
|
|
|
OnStateChange?.Invoke();
|
|
updateBindables();
|
|
}
|
|
|
|
/// <summary>
|
|
/// Write a serialised copy of the currently tracked state to the provided stream.
|
|
/// This will be stored as a state which can be restored in the future.
|
|
/// </summary>
|
|
/// <param name="stream">The stream which the state should be written to.</param>
|
|
protected abstract void WriteCurrentStateToStream(MemoryStream stream);
|
|
|
|
/// <summary>
|
|
/// Given a previous and new state, apply any changes required to bring the current state in line with the new state.
|
|
/// </summary>
|
|
/// <param name="previousState">The previous (current before this call) serialised state.</param>
|
|
/// <param name="newState">The new state to be applied.</param>
|
|
protected abstract void ApplyStateChange(byte[] previousState, byte[] newState);
|
|
|
|
private void updateBindables()
|
|
{
|
|
CanUndo.Value = savedStates.Count > 0 && currentState > 0;
|
|
CanRedo.Value = currentState < savedStates.Count - 1;
|
|
}
|
|
}
|
|
}
|