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