mirror of https://github.com/ppy/osu
74 lines
2.4 KiB
C#
74 lines
2.4 KiB
C#
// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
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// See the LICENCE file in the repository root for full licence text.
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using System;
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using osu.Framework.Graphics;
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namespace osu.Game.Screens.Edit
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{
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/// <summary>
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/// A component that tracks a batch change, only applying after all active changes are completed.
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/// </summary>
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public abstract class TransactionalCommitComponent : Component
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{
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/// <summary>
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/// Fires whenever a transaction begins. Will not fire on nested transactions.
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/// </summary>
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public event Action TransactionBegan;
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/// <summary>
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/// Fires when the last transaction completes.
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/// </summary>
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public event Action TransactionEnded;
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/// <summary>
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/// Fires when <see cref="SaveState"/> is called and results in a non-transactional state save.
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/// </summary>
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public event Action SaveStateTriggered;
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public bool TransactionActive => bulkChangesStarted > 0;
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private int bulkChangesStarted;
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/// <summary>
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/// Signal the beginning of a change.
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/// </summary>
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public void BeginChange()
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{
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if (bulkChangesStarted++ == 0)
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TransactionBegan?.Invoke();
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}
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/// <summary>
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/// Signal the end of a change.
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/// </summary>
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/// <exception cref="InvalidOperationException">Throws if <see cref="BeginChange"/> was not first called.</exception>
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public void EndChange()
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{
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if (bulkChangesStarted == 0)
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throw new InvalidOperationException($"Cannot call {nameof(EndChange)} without a previous call to {nameof(BeginChange)}.");
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if (--bulkChangesStarted == 0)
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{
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UpdateState();
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TransactionEnded?.Invoke();
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}
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}
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/// <summary>
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/// Force an update of the state with no attached transaction.
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/// This is a no-op if a transaction is already active. Should generally be used as a safety measure to ensure granular changes are not left outside a transaction.
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/// </summary>
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public void SaveState()
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{
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if (bulkChangesStarted > 0)
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return;
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SaveStateTriggered?.Invoke();
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UpdateState();
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}
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protected abstract void UpdateState();
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}
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}
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