SettingsEntry.cs

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// Copyright (c) 2014 Silicon Studio Corp. (http://siliconstudio.co.jp)
// This file is distributed under GPL v3. See LICENSE.md for details.
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

using SiliconStudio.ActionStack;
using SiliconStudio.Core.IO;

namespace SiliconStudio.Presentation.Settings
{
    /// <summary>
    /// An internal object that represent a value for a settings key into a <see cref="SettingsProfile"/>.
    /// </summary>
    internal abstract class SettingsEntry
    {
        protected readonly SettingsProfile Profile;
        protected bool ShouldNotify;
        private object value;

        /// <summary>
        /// Initializes a new instance of the <see cref="SettingsEntry"/> class.
        /// </summary>
        /// <param name="profile">The profile this <see cref="SettingsEntry"/>belongs to.</param>
        /// <param name="name">The name associated to this <see cref="SettingsEntry"/>.</param>
        protected SettingsEntry(SettingsProfile profile, UFile name)
        {
            if (profile == null) throw new ArgumentNullException("profile");
            if (name == null) throw new ArgumentNullException("name");
            Profile = profile;
            Name = name;
        }

        /// <summary>
        /// Gets the name of this <see cref="SettingsEntry"/>.
        /// </summary>
        internal UFile Name { get; private set; }

        /// <summary>
        /// Gets or sets the value of this <see cref="SettingsEntry"/>.
        /// </summary>
        internal object Value { get { return value; } set { UpdateValue(value); } }

        /// <summary>
        /// Creates a new instance of a class derived from <see cref="SettingsEntry"/> that matches the type of the given value. 
        /// </summary>
        /// <param name="profile">The profile the <see cref="SettingsEntry"/> to create belongs to.</param>
        /// <param name="name">The name associated to the <see cref="SettingsEntry"/> to create.</param>
        /// <param name="value">The value to associate to the <see cref="SettingsEntry"/> to create.</param>
        /// <returns>A new instance of a <see cref="SettingsEntry"/> class.</returns>
        internal static SettingsEntry CreateFromValue(SettingsProfile profile, UFile name, object value)
        {
            if (profile == null) throw new ArgumentNullException("profile");
            if (name == null) throw new ArgumentNullException("name");
            if (value != null)
            {
                Type type = value.GetType();
                // Check if we have a list interface...
                if (value is IList || type.GetInterfaces().Any(x => x.IsGenericType && x.GetGenericTypeDefinition() == typeof(IList<>)))
                {
                    var listItems = (IEnumerable)value;
                    var genericListInterface = type.GetInterfaces().FirstOrDefault(x => x.IsGenericType && x.GetGenericTypeDefinition() == typeof(IList<>));
                    if (genericListInterface != null)
                    {
                        var itemType = genericListInterface.GetGenericArguments()[0];
                        var result = (SettingsEntry)Activator.CreateInstance(typeof(SettingsEntryList<>).MakeGenericType(itemType), profile, name, listItems);
                        return result;
                    }
                    return new SettingsEntryList<object>(profile, name, listItems);
                }
            }

            return new SettingsEntryValue(profile, name, value);
        }

        /// <summary>
        /// Gets the value of this entry converted to a serializable type.
        /// </summary>
        /// <returns></returns>
        internal abstract object GetSerializableValue();

        private void UpdateValue(object newValue)
        {
            var oldValue = value;
            bool changed = !Equals(oldValue, newValue);
            if (changed && ShouldNotify && !Profile.IsDiscarding)
            {
                var actionItem = new PropertyChangedActionItem("Value", this, oldValue);
                Profile.ActionStack.Add(actionItem);
                Profile.NotifyEntryChanged(Name);
            }
            value = newValue;
        }
    }
}