mcs/class/System/System.Diagnostics/DefaultTraceListener.cs

   1 //
   2 // System.Diagnostics.DefaultTraceListener.cs
   3 //
   4 // Authors:
   5 //   Jonathan Pryor (jonpryor@vt.edu)
   6 //
   7 // Comments from John R. Hicks <angryjohn69@nc.rr.com> original implementation
   8 // can be found at: /mcs/docs/apidocs/xml/en/System.Diagnostics
   9 //
  10 // (C) 2002 Jonathan Pryor
  11 //
  12
  13 //
  14 // Permission is hereby granted, free of charge, to any person obtaining
  15 // a copy of this software and associated documentation files (the
  16 // "Software"), to deal in the Software without restriction, including
  17 // without limitation the rights to use, copy, modify, merge, publish,
  18 // distribute, sublicense, and/or sell copies of the Software, and to
  19 // permit persons to whom the Software is furnished to do so, subject to
  20 // the following conditions:
  21 //
  22 // The above copyright notice and this permission notice shall be
  23 // included in all copies or substantial portions of the Software.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  32 //
  33
  34 using System;
  35 using System.IO;
  36 using System.Collections;
  37 using System.Diagnostics;
  38 using System.Runtime.CompilerServices;
  39 using System.Runtime.InteropServices;
  40
  41 namespace System.Diagnostics {
  42
  43         [ComVisible(false)]
  44         public class DefaultTraceListener : TraceListener {
  45
  46                 private static readonly bool OnWin32;
  47
  48                 private const string ConsoleOutTrace = "Console.Out";
  49                 private const string ConsoleErrorTrace = "Console.Error";
  50
  51                 private static readonly string MonoTracePrefix;
  52                 private static readonly string MonoTraceFile;
  53
  54                 static DefaultTraceListener ()
  55                 {
  56                         // Determine what platform we're on.  This impacts how where we send
  57                         // messages.  On Win32 platforms (OnWin32 = true), we use the
  58                         // `OutputDebugString' api.
  59                         //
  60                         // On Linux platforms, we use MONO_TRACE_LISTENER to figure things out.  See the
  61                         // API documentation for more information on MONO_TRACE_LISTENER.
  62                         OnWin32 = (Path.DirectorySeparatorChar == '\\');
  63
  64                         if (!OnWin32) {
  65                                 // If we're running on Unix, we don't have OutputDebugString.
  66                                 // Instead, send output to...wherever the MONO_TRACE_LISTENER environment
  67                                 // variables says to.
  68                                 String trace = Environment.GetEnvironmentVariable("MONO_TRACE_LISTENER");
  69
  70                                 if (trace != null) {
  71                                         string file = null;
  72                                         string prefix = null;
  73
  74                                         if (trace.StartsWith (ConsoleOutTrace)) {
  75                                                 file = ConsoleOutTrace;
  76                                                 prefix = GetPrefix (trace, ConsoleOutTrace);
  77                                         }
  78                                         else if (trace.StartsWith (ConsoleErrorTrace)) {
  79                                                 file = ConsoleErrorTrace;
  80                                                 prefix = GetPrefix (trace, ConsoleErrorTrace);
  81                                         }
  82                                         else {
  83                                                 file = trace;
  84
  85                                                 // We can't firgure out what the prefix would be, as ':' is a
  86                                                 // valid filename character.  Thus, arbitrary files don't support
  87                                                 // prefixes.
  88                                                 //
  89                                                 // I don't consider this to be a major issue.  Prefixes are useful
  90                                                 // with Console.Out and Console.Error to help separate trace
  91                                                 // output from the actual program output.  Writing to an arbitrary
  92                                                 // file doesn't introduce issues with disambiguation.
  93                                                 prefix = "";
  94                                         }
  95
  96                                         MonoTraceFile = file;
  97                                         MonoTracePrefix = prefix;
  98                                 }
  99                         }
 100                 }
 101
 102                 /**
 103                  * Get the prefix for the specified variable.
 104                  *
 105                  * "Prefixes" are used in the MONO_TRACE_LISTENER variable, and specify text that
 106                  * should precede each message printed to the console.  The prefix is
 107                  * appended to the console location with a colon (':') separating them.
 108                  * For example, if MONO_TRACE_LISTENER is "Console.Out:** my prefix", the prefix is
 109                  * "** my prefix".
 110                  *
 111                  * Everything after the colon, if the colon is present, is used as the
 112                  * prefix.
 113                  *
 114                  * @param       var             The current MONO_TRACE_LISTENER variable
 115                  * @param       target  The name of the output location, e.g. "Console.Out"
 116                  */
 117                 private static string GetPrefix (string var, string target)
 118                 {
 119                         // actually, we permit any character to separate `target' and the prefix;
 120                         // we just skip over target the ':' would be.  This means that a space or
 121                         // anything else would suffice, as long as it was only a single
 122                         // character.
 123                         if (var.Length > target.Length)
 124                                 return var.Substring (target.Length + 1);
 125                         return "";
 126                 }
 127
 128                 private string logFileName = null;
 129
 130                 private bool assertUiEnabled = false;
 131
 132                 public DefaultTraceListener () : base ("Default")
 133                 {
 134                 }
 135
 136                 // It's hard to do anything with a UI when we don't have Windows.Forms...
 137                 [MonoTODO]
 138                 public bool AssertUiEnabled {
 139                         get {return assertUiEnabled;}
 140                         set {/* ignore */}
 141                 }
 142
 143                 [MonoTODO]
 144                 public string LogFileName {
 145                         get {return logFileName;}
 146                         set {logFileName = value;}
 147                 }
 148
 149                 public override void Fail (string message)
 150                 {
 151                         base.Fail (message);
 152                         WriteLine (new StackTrace().ToString());
 153                 }
 154
 155                 public override void Fail (string message, string detailMessage)
 156                 {
 157                         base.Fail (message, detailMessage);
 158                         WriteLine (new StackTrace().ToString());
 159                 }
 160
 161                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
 162                 private extern static void WriteWindowsDebugString (string message);
 163
 164                 private void WriteDebugString (string message)
 165                 {
 166                         if (OnWin32)
 167                                 WriteWindowsDebugString (message);
 168                         else
 169                                 WriteMonoTrace (message);
 170                 }
 171
 172                 private void WriteMonoTrace (string message)
 173                 {
 174                         switch (MonoTraceFile) {
 175                         case ConsoleOutTrace:
 176                                 Console.Out.Write (message);
 177                                 break;
 178                         case ConsoleErrorTrace:
 179                                 Console.Error.Write (message);
 180                                 break;
 181                         default:
 182                                 WriteLogFile (message, MonoTraceFile);
 183                                 break;
 184                         }
 185                 }
 186
 187                 private void WritePrefix ()
 188                 {
 189                         if (!OnWin32) {
 190                                 WriteMonoTrace (MonoTracePrefix);
 191                         }
 192                 }
 193
 194                 private void WriteImpl (string message)
 195                 {
 196                         if (NeedIndent) {
 197                                 WriteIndent ();
 198                                 WritePrefix ();
 199                         }
 200
 201                         WriteDebugString (message);
 202
 203                         if (Debugger.IsLogging())
 204                                 Debugger.Log (0, null, message);
 205
 206                         WriteLogFile (message, LogFileName);
 207                 }
 208
 209                 private void WriteLogFile (string message, string logFile)
 210                 {
 211                         string fname = logFile;
 212                         if (fname != null && fname.Length != 0) {
 213                                 FileInfo info = new FileInfo (fname);
 214                                 StreamWriter sw = null;
 215
 216                                 // Open the file
 217                                 try {
 218                                         if (info.Exists)
 219                                                 sw = info.AppendText ();
 220                                         else
 221                                                 sw = info.CreateText ();
 222                                 }
 223                                 catch {
 224                                         // We weren't able to open the file for some reason.
 225                                         // We can't write to the log file; so give up.
 226                                         return;
 227                                 }
 228
 229                                 using (sw) {
 230                                         sw.Write (message);
 231                                         sw.Flush ();
 232                                 }
 233                         }
 234                 }
 235
 236                 public override void Write (string message)
 237                 {
 238                         WriteImpl (message);
 239                 }
 240
 241                 public override void WriteLine (string message)
 242                 {
 243                         string msg = message + Environment.NewLine;
 244                         WriteImpl (msg);
 245
 246                         NeedIndent = true;
 247                 }
 248         }
 249 }
 250