using System;
namespace UnityEditor.Rendering
{
/// <summary>Used in editor drawer part to store the state of expandable areas.</summary>
/// <typeparam name="TState">An enum to use to describe the state.</typeparam>
public abstract class ExpandedStateBase<TState>
where TState : struct, IConvertible
{
/// <summary>Accessor to the expended state of this specific mask.</summary>
/// <param name="mask">The filtering mask</param>
/// <returns>True: All flagged area are expended</returns>
public abstract bool GetExpandedAreas(TState mask);
/// <summary>Setter to the expended state.</summary>
/// <param name="mask">The filtering mask</param>
/// <param name="value">The expended state to set</param>
public abstract void SetExpandedAreas(TState mask, bool value);
/// <summary> Utility to set all states to true </summary>
public abstract void ExpandAll();
/// <summary> Utility to set all states to false </summary>
public abstract void CollapseAll();
/// <summary>Get or set the state given the mask.</summary>
/// <param name="mask">The filtering mask</param>
/// <value>True: All flagged area are expended</value>
public bool this[TState mask]
{
get => GetExpandedAreas(mask);
set => SetExpandedAreas(mask, value);
}
}
/// <summary>Used in editor drawer part to store the state of expandable areas using EditorPrefBoolFlags.</summary>
/// <typeparam name="TState">An enum to use to describe the state.</typeparam>
/// <typeparam name="TTarget">A type given to automatically compute the key.</typeparam>
public class ExpandedState<TState, TTarget> : ExpandedStateBase<TState>
where TState : struct, IConvertible
{
/// <summary>
/// The variable which stores the state of expandable areas.
/// </summary>
protected internal EditorPrefBoolFlags<TState> m_State;
/// <summary>
/// Constructor will create the key to store in the EditorPref the state given generic type passed.
/// The key will be formated as such prefix:TTarget:TState:UI_State.
/// </summary>
/// <param name="defaultValue">If key did not exist, it will be created with this value for initialization.</param>
/// <param name="prefix">[Optional] Prefix scope of the key (Default is CoreRP)</param>
/// <param name="stateId">[Optional] Postfix used to differentiate between different keys (Default is UI_State)</param>
public ExpandedState(TState defaultValue, string prefix = "CoreRP", string stateId = "UI_State")
{
string key = $"{prefix}:{typeof(TTarget).Name}:{typeof(TState).Name}:{stateId}";
m_State = new EditorPrefBoolFlags<TState>(key);
//register key if not already there
if (!EditorPrefs.HasKey(key))
{
EditorPrefs.SetInt(key, (int)(object)defaultValue);
}
}
/// <inheritdoc/>
public override bool GetExpandedAreas(TState mask)
{
return m_State.HasFlag(mask);
}
/// <inheritdoc/>
public override void SetExpandedAreas(TState mask, bool value)
{
m_State.SetFlag(mask, value);
}
/// <inheritdoc/>
public override void ExpandAll()
{
m_State.rawValue = uint.MaxValue;
}
/// <inheritdoc/>
public override void CollapseAll()
{
m_State.rawValue = 0u;
}
}
/// <summary>Used in editor drawer part to store the state of expandable areas using EditorPrefBoolFlags for a list of elements.</summary>
/// <typeparam name="TTarget">A type given to automatically compute the key.</typeparam>
public class ExpandedStateList<TTarget> : ExpandedState<int, TTarget>
{
/// <summary>
/// Constructor will create the key to store in the EditorPref the state given generic type passed.
/// The key will be formated as such prefix:TTarget:TState:UI_State.
/// </summary>
/// <param name="prefix">[Optional] Prefix scope of the key (Default is CoreRP)</param>
public ExpandedStateList(string prefix = "CoreRP")
: base(default(int), prefix, "UI_State_List") { }
/// <summary>
/// Swap flag between src index and dst index.
/// </summary>
/// <param name="srcIndex">src index to swap.</param>
/// <param name="dstIndex">dst index to swap.</param>
public void SwapFlags(int srcIndex, int dstIndex)
{
int srcFlag = 1 << srcIndex;
int dstFlag = 1 << dstIndex;
bool srcVal = GetExpandedAreas(srcFlag);
SetExpandedAreas(srcFlag, GetExpandedAreas(dstFlag));
SetExpandedAreas(dstFlag, srcVal);
}
/// <summary> Removes a flag at a given index which causes the following flags' index to decrease by one.</summary>
/// <param name="index">The index of the flag to be removed.</param>
public void RemoveFlagAtIndex(int index)
{
m_State.rawValue = RightShiftOnceFromIndexToMSB(index, m_State.rawValue);
}
/// <summary> Utility to logical right shift every bit from the index flag to MSB resulting in the index flag being shifted out.<\summary>
/// <param name="index">Right shift every bit greater or equal to the index.</param>
/// <param name="value">Value to make the operations on.</param>
/// <returns>The right shift value after the given index.</returns>
internal static uint RightShiftOnceFromIndexToMSB(int index, uint value)
{ // Example of each operation:
// 1011 1001 - Value
uint indexBit = 1u << index; // 0000 1000 - Index bit
uint remainArea = indexBit - 1u; // 0000 0111
uint remainBits = remainArea & value; // 0000 0001
uint movedBits = (~remainArea - indexBit & value) >> 1; // 1111 1000
// 1111 0000
// 1011 0000
// 0101 1000
return movedBits | remainBits; // 0101 1001 - Result
}
}
}