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//---------------------------------------------------------------------
// <copyright file="LazyTextWriterCreator.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//
// @owner [....]
// @backupOwner [....]
//---------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Diagnostics;
using System.Runtime.Versioning;
namespace System.Data.Entity.Design
{
/// <summary>
/// This class is responsible for abstracting the knowledge
/// of whether the user provided a TextWriter or a FilePath.
///
/// If the user gave us a filePath we try not to create the TextWriter
/// till we absolutely need it in order to prevent the file from being created
/// in error cases.
/// </summary>
internal class LazyTextWriterCreator : IDisposable
{
private bool _ownTextWriter;
private TextWriter _writer = null;
private string _targetFilePath = null;
internal LazyTextWriterCreator(TextWriter writer)
{
Debug.Assert(writer != null, "writer parameter is null");
_ownTextWriter = false;
_writer = writer;
}
[ResourceExposure(ResourceScope.Machine)] //The target file path is used to open a stream which is a machine resource.
internal LazyTextWriterCreator(string targetFilePath)
{
Debug.Assert(targetFilePath != null, "targetFilePath parameter is null");
_ownTextWriter = true;
_targetFilePath = targetFilePath;
}
[ResourceExposure(ResourceScope.None)] //The resource( target file path) is not exposed to the callers of this method
[ResourceConsumption(ResourceScope.Machine, ResourceScope.Machine)] //For StreamWriter constructor and we pick
//the target file path from class variable.
internal TextWriter GetOrCreateTextWriter()
{
if (_writer == null)
{
// lazy creating the writer
_writer = new StreamWriter(_targetFilePath);
}
return _writer;
}
internal string TargetFilePath
{
get { return _targetFilePath; }
}
internal bool IsUserSuppliedTextWriter
{
get { return !_ownTextWriter; }
}
public void Dispose()
{
// Technically, calling GC.SuppressFinalize is not required because the class does not
// have a finalizer, but it does no harm, protects against the case where a finalizer is added
// in the future, and prevents an FxCop warning.
GC.SuppressFinalize(this);
if (_ownTextWriter && _writer != null)
{
_writer.Dispose();
}
}
}
}
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