//---------------------------------------------------------------------
// <copyright file="SymbolUsageManager.cs" company="Microsoft">
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
//
// @owner  Microsoft
//---------------------------------------------------------------------
 
using System;
using System.Collections.Generic;
 
namespace System.Data.SqlClient.SqlGen
{
    /// <summary>
    /// Used for wrapping a boolean value as an object.
    /// </summary>
    internal class BoolWrapper
    {
        internal bool Value {get; set;}
 
        internal BoolWrapper()
        {
            this.Value = false;
        }
    }
 
    /// <summary>
    /// Tracks the usage of symbols. 
    /// When registering a symbol with the usage manager if an input symbol is specified,
    /// than the usage of the two is 'connected' - if one ever gets marked as used, 
    /// the other one becomes 'used' too. 
    /// </summary>
    internal class SymbolUsageManager
    {
        private readonly Dictionary<Symbol, BoolWrapper> optionalColumnUsage = new Dictionary<Symbol, BoolWrapper>();
 
        internal bool ContainsKey(Symbol key)
        {
            return optionalColumnUsage.ContainsKey(key);
        }
 
        internal bool TryGetValue(Symbol key, out bool value)
        {
            BoolWrapper wrapper;
            if (optionalColumnUsage.TryGetValue(key, out wrapper))
            {
                value = wrapper.Value;
                return true;
            }
 
            value = false;
            return false;
        }
 
        internal void Add(Symbol sourceSymbol, Symbol symbolToAdd)
        {
            BoolWrapper wrapper;
            if (sourceSymbol == null || !this.optionalColumnUsage.TryGetValue(sourceSymbol, out wrapper))
            {
                wrapper = new BoolWrapper();
            }
            this.optionalColumnUsage.Add(symbolToAdd, wrapper);
        }
 
        internal void MarkAsUsed(Symbol key)
        {
            if (optionalColumnUsage.ContainsKey(key))
            {
                optionalColumnUsage[key].Value = true;
            }
        }
 
        internal bool IsUsed(Symbol key)
        {
            return optionalColumnUsage[key].Value;
        }
    }
}