mcs/class/referencesource/System.Data.Entity/System/Data/SqlClient/SqlGen/SymbolUsageManager.cs

   1 //---------------------------------------------------------------------
   2 // <copyright file="SymbolUsageManager.cs" company="Microsoft">
   3 //      Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 //
   6 // @owner  Microsoft
   7 //---------------------------------------------------------------------
   8
   9 using System;
  10 using System.Collections.Generic;
  11
  12 namespace System.Data.SqlClient.SqlGen
  13 {
  14     /// <summary>
  15     /// Used for wrapping a boolean value as an object.
  16     /// </summary>
  17     internal class BoolWrapper
  18     {
  19         internal bool Value {get; set;}
  20
  21         internal BoolWrapper()
  22         {
  23             this.Value = false;
  24         }
  25     }
  26
  27     /// <summary>
  28     /// Tracks the usage of symbols.
  29     /// When registering a symbol with the usage manager if an input symbol is specified,
  30     /// than the usage of the two is 'connected' - if one ever gets marked as used,
  31     /// the other one becomes 'used' too.
  32     /// </summary>
  33     internal class SymbolUsageManager
  34     {
  35         private readonly Dictionary<Symbol, BoolWrapper> optionalColumnUsage = new Dictionary<Symbol, BoolWrapper>();
  36
  37         internal bool ContainsKey(Symbol key)
  38         {
  39             return optionalColumnUsage.ContainsKey(key);
  40         }
  41
  42         internal bool TryGetValue(Symbol key, out bool value)
  43         {
  44             BoolWrapper wrapper;
  45             if (optionalColumnUsage.TryGetValue(key, out wrapper))
  46             {
  47                 value = wrapper.Value;
  48                 return true;
  49             }
  50
  51             value = false;
  52             return false;
  53         }
  54
  55         internal void Add(Symbol sourceSymbol, Symbol symbolToAdd)
  56         {
  57             BoolWrapper wrapper;
  58             if (sourceSymbol == null || !this.optionalColumnUsage.TryGetValue(sourceSymbol, out wrapper))
  59             {
  60                 wrapper = new BoolWrapper();
  61             }
  62             this.optionalColumnUsage.Add(symbolToAdd, wrapper);
  63         }
  64
  65         internal void MarkAsUsed(Symbol key)
  66         {
  67             if (optionalColumnUsage.ContainsKey(key))
  68             {
  69                 optionalColumnUsage[key].Value = true;
  70             }
  71         }
  72
  73         internal bool IsUsed(Symbol key)
  74         {
  75             return optionalColumnUsage[key].Value;
  76         }
  77     }
  78 }