Mono源代码学习笔记:Console类(五)

CStreamReader 类 (internal class)

下面就是 mcs/class/corlib/System/CStreamReader.cs：

001:  //002:  // System.CStreamReader003:  //004:  // Authors:005:  //   Dietmar Maurer ([e-mail])006:  //   Miguel de Icaza ([e-mail])007:  //   Dick Porter ([e-mail])008:  //   Sebastien Pouliot  <[e-mail]>009:  //010:  // (C) Ximian, Inc.  http://www.ximian.com011:  // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)012:  //013:  // Permission is hereby granted, free of charge, to any person obtaining014:  // a copy of this software and associated documentation files (the015:  // "Software"), to deal in the Software without restriction, including016:  // without limitation the rights to use, copy, modify, merge, publish,017:  // distribute, sublicense, and/or sell copies of the Software, and to018:  // permit persons to whom the Software is furnished to do so, subject to019:  // the following conditions:020:  // 021:  // The above copyright notice and this permission notice shall be022:  // included in all copies or substantial portions of the Software.023:  // 024:  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,025:  // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF026:  // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND027:  // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE028:  // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION029:  // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION030:  // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.031:  //032:  #if !NET_2_1033:  using System.Text;034:  using System.Runtime.InteropServices;035:  036:  namespace System.IO {037:      class CStreamReader : StreamReader {038:          TermInfoDriver driver;039:  040:          public CStreamReader(Stream stream, Encoding encoding)041:              : base (stream, encoding)042:          {043:              driver = (TermInfoDriver) ConsoleDriver.driver;044:          }045:  046:          public override int Peek ()047:          {048:              try {049:                  return base.Peek ();050:              } catch (IOException) {051:              }052:  053:              return -1;054:          }055:  056:          public override int Read ()057:          {058:              try {059:                  ConsoleKeyInfo key = Console.ReadKey ();060:                  return key.KeyChar;061:              } catch (IOException) {062:              }063:  064:              return(-1);065:          }066:  067:          public override int Read ([In, Out] char [] dest, int index, int count)068:          {069:              if (dest == null)070:                  throw new ArgumentNullException ("dest");071:              if (index < 0)072:                  throw new ArgumentOutOfRangeException ("index", "< 0");073:              if (count < 0)074:                  throw new ArgumentOutOfRangeException ("count", "< 0");075:              // ordered to avoid possible integer overflow076:              if (index > dest.Length - count)077:                  throw new ArgumentException ("index + count > dest.Length");078:  079:              try {080:                  return driver.Read (dest, index, count);081:              } catch (IOException) {082:              }083:  084:              return 0;085:          }086:  087:          public override string ReadLine ()088:          {089:              try {090:                  return driver.ReadLine ();091:              } catch (IOException) {092:              }093:  094:              return null;095:          }096:  097:          public override string ReadToEnd ()098:          {099:              try {100:                  return (base.ReadToEnd ());101:              } catch (IOException) {102:              }103:  104:              return null;105:          }106:      }107:  }108:  #endif

上述源程序定义了 CStreamReader 类。该类位于 System.IO 命名空间中，继承自 StreamReader 类，是 internal 的，只能在本程序集内部使用。我想 CStreamReader 这个名称应该意味着 Console Stream Reader。

第 2 行的注释“System.CStreamReader”有误，应改为“System.IO.CStreamReader”。此外，CStreamReader.cs 放在 mcs/class/corlib/System 目录下也不合理，应该放在 mcs/class/corlib/System.IO 目录下才对。

第 38 行定义了一个类型为 TermInfoDriver 的私有实例字段 driver。

第 40 行到第 44 行的公共构造函数用它的两个参数调用其基类 StreamReader 的相应构造函数，然后对 driver 字段进行赋值。

第 46 行到第 54 行以及第 97 行到第 105 行的两个公共方法重写了基类 StreamReader 对应的虚方法，并简单地调用基类的对应的虚方法，捕获并忽略 IOException 异常。

第 56 行到第 65 行的 Read 公共方法重写了基类 StreamReader 对应的虚方法，通过调用 Console 类的公共静态方法 ReadKey 来达到目的，同样捕获并忽略 IOException 异常。

第 67 行到第 95 行的两个公共方法重写了基类 StreamReader 对应的虚方法，通过私有实例字段 driver 调用 TermInfoDriver 类相应的公共实例方法来达到目的，同样捕获并忽略 IOException 异常。

在 Console.dll 项目中，CStreamReader 类在 Console.cs 中被使用。

CStreamWriter 类 (internal class)

下面就是 mcs/class/corlib/System/CStreamWriter.cs：

001:  //002:  // System.CStreamWriter003:  //004:  // Authors:005:  //   Dietmar Maurer ([e-mail])006:  //   Paolo Molaro ([e-mail])007:  //   Dick Porter ([e-mail])008:  //009:  // (c) 2006 Novell, Inc.  http://www.novell.com010:  //011:  012:  //013:  // Copyright (C) 2004 Novell, Inc (http://www.novell.com)014:  //015:  // Permission is hereby granted, free of charge, to any person obtaining016:  // a copy of this software and associated documentation files (the017:  // "Software"), to deal in the Software without restriction, including018:  // without limitation the rights to use, copy, modify, merge, publish,019:  // distribute, sublicense, and/or sell copies of the Software, and to020:  // permit persons to whom the Software is furnished to do so, subject to021:  // the following conditions:022:  // 023:  // The above copyright notice and this permission notice shall be024:  // included in all copies or substantial portions of the Software.025:  // 026:  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,027:  // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF028:  // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND029:  // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE030:  // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION031:  // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION032:  // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.033:  //034:  #if !NET_2_1035:  using System;036:  using System.Text;037:  038:  namespace System.IO {039:      class CStreamWriter : StreamWriter {040:          TermInfoDriver driver;041:  042:          public CStreamWriter (Stream stream, Encoding encoding)043:              : base (stream, encoding)044:          {045:              driver = (TermInfoDriver) ConsoleDriver.driver;046:          }047:  048:          public override void Write (char [] buffer, int index, int count)049:          {050:              if (count <= 0)051:                  return;052:              053:              if (!driver.Initialized) {054:                  try {055:                      base.Write (buffer, index, count);056:                  } catch (IOException) {057:                  }058:                  059:                  return;060:              }061:              062:              lock (this) {063:                  int last = index + count;064:                  int i = index;065:                  int n = 0;066:                  char c;067:  068:                  do {069:                      c = buffer [i++];070:  071:                      if (driver.IsSpecialKey (c)) {072:                          // flush what we have073:                          if (n > 0) {074:                              try {075:                                  base.Write (buffer, index, n);076:                              } catch (IOException) {077:                              }078:                              079:                              n = 0;080:                          }081:  082:                          // write the special key083:                          driver.WriteSpecialKey (c);084:  085:                          index = i;086:                      } else {087:                          n++;088:                      }089:                  } while (i < last);090:  091:                  if (n > 0) {092:                      // write out the remainder of the buffer093:                      try {094:                          base.Write (buffer, index, n);095:                      } catch (IOException) {096:                      }097:                  }098:              }099:          }100:  101:          public override void Write (char val)102:          {103:              lock (this) {104:                  try {105:                      if (driver.IsSpecialKey (val))106:                          driver.WriteSpecialKey (val);107:                      else108:                          InternalWriteChar (val);109:                  } catch (IOException) {110:                  }111:              }112:          }113:  114:          public void WriteKey (ConsoleKeyInfo key)115:          {116:              lock (this) {117:                  ConsoleKeyInfo copy = new ConsoleKeyInfo (key);118:                  if (driver.IsSpecialKey (copy))119:                      driver.WriteSpecialKey (copy);120:                  else121:                      InternalWriteChar (copy.KeyChar);122:              }123:          }124:  125:          public void InternalWriteString (string val)126:          {127:              try {128:                  base.Write (val);129:              } catch (IOException) {130:              }131:          }132:  133:          public void InternalWriteChar (char val)134:          {135:              try {136:                  base.Write (val);137:              } catch (IOException) {138:              }139:          }140:  141:          public void InternalWriteChars (char [] buffer, int n)142:          {143:              try {144:                  base.Write (buffer, 0, n);145:              } catch (IOException) {146:              }147:          }148:  149:          public override void Write (char [] val)150:          {151:              Write (val, 0, val.Length);152:          }153:  154:          public override void Write (string val)155:          {156:              if (val == null)157:                  return;158:              159:              if (driver.Initialized)160:                  Write (val.ToCharArray ());161:              else {162:                  try {163:                      base.Write (val);164:                  } catch (IOException){165:                      166:                  }167:              }168:          }169:      }170:  }171:  #endif

上述源程序定义了 CStreamWriter 类。该类位于 System.IO 命名空间中，继承自 StreamWriter 类，是 internal 的，只能在本程序集内部使用。我想 CStreamWriter 这个名称应该意味着 Console Stream Writer。

第 2 行的注释“System.CStreamWriter”有误，应改为“System.IO.CStreamWriter”。此外，CStreamWriter.cs 放在 mcs/class/corlib/System 目录下也不合理，应该放在 mcs/class/corlib/System.IO 目录下才对。

第 40 行定义了一个类型为 TermInfoDriver 的私有实例字段 driver。

第 42 行到第 46 行的公共构造函数用它的两个参数调用其基类 StreamWriter 的相应构造函数，然后对 driver 字段进行赋值。

第 48 到第 99 行的 Write 公共方法重写了基类 StreamWriter 对应的虚方法。如果检查到私有实例字段 driver 末初始化的话，就通过调用基类对应的虚方法来实现其功能，捕获并忽略 IOException 异常。否则的话，还通过 driver 字段对要写入的字符数组中的特殊字符进行特殊处理。

第 101 行到第 168 行的七个公共方法同样在调用基类的方法时捕获并忽略 IOException 异常。也在必要时通过 driver 字段对特殊字符进行特殊处理。

在 Console.dll 项目中，CStreamWriter 类在 Console.cs 和 TermInfoDriver.cs 中被使用。