mcs/class/corlib/System/Console.iOS.cs

   1 //
   2 // Helper for Console to allow indirect access to `stdout` using NSLog
   3 //
   4 // Authors:
   5 //      Sebastien Pouliot  <sebastien@xamarin.com>
   6 //
   7 // Copyright 2012-2014 Xamarin Inc. All rights reserved.
   8 //
   9
  10 #if FULL_AOT_RUNTIME
  11
  12 using System;
  13 using System.IO;
  14 using System.Runtime.InteropServices;
  15 using System.Text;
  16
  17 namespace System {
  18
  19         public static partial class Console {
  20
  21                 class NSLogWriter : TextWriter {
  22                         [DllImport ("__Internal", CharSet=CharSet.Unicode)]
  23                         extern static void monotouch_log (string s);
  24
  25                         [DllImport ("/usr/lib/libSystem.dylib")]
  26                         extern static /* ssize_t */ IntPtr write (int fd, byte [] buffer, /* size_t */ IntPtr n);
  27
  28                         StringBuilder sb;
  29
  30                         public NSLogWriter ()
  31                         {
  32                                 sb = new StringBuilder ();
  33                         }
  34
  35                         public override System.Text.Encoding Encoding {
  36                                 get { return System.Text.Encoding.UTF8; }
  37                         }
  38
  39                         static void direct_write_to_stdout (string s)
  40                         {
  41                                 byte [] b = Encoding.Default.GetBytes (s);
  42                                 var len = (IntPtr) b.Length;
  43                                 while ((int) write (1, b, len) == -1 && Marshal.GetLastWin32Error () == /* EINTR*/ 4)
  44                                         ;
  45                         }
  46
  47                         public override void Flush ()
  48                         {
  49                                 string s = sb.ToString ();
  50                                 try {
  51                                         monotouch_log (s);
  52                                 }
  53                                 catch (Exception) {
  54                                         try {
  55                                                 direct_write_to_stdout (s);
  56                                                 direct_write_to_stdout (Environment.NewLine);
  57                                         } catch (Exception){}
  58                                 }
  59                                 sb.Length = 0;
  60                         }
  61
  62                         // minimum to override - see http://msdn.microsoft.com/en-us/library/system.io.textwriter.aspx
  63                         public override void Write (char value)
  64                         {
  65                                 try {
  66                                         sb.Append (value);
  67                                 }
  68                                 catch (Exception) {
  69                                 }
  70                         }
  71
  72                         // optimization (to avoid concatening chars)
  73                         public override void Write (string value)
  74                         {
  75                                 try {
  76                                         sb.Append (value);
  77                                         if (value != null && value.Length >= CoreNewLine.Length && EndsWithNewLine (value))
  78                                                 Flush ();
  79                                 }
  80                                 catch (Exception) {
  81                                 }
  82                         }
  83
  84                         bool EndsWithNewLine (string value)
  85                         {
  86                                 for (int i = 0, v = value.Length - CoreNewLine.Length; i < CoreNewLine.Length; ++i, ++v) {
  87                                         if (value [v] != CoreNewLine [i])
  88                                                 return false;
  89                                 }
  90
  91                                 return true;
  92                         }
  93
  94                         public override void WriteLine ()
  95                         {
  96                                 try {
  97                                         Flush ();
  98                                 }
  99                                 catch (Exception) {
 100                                 }
 101                         }
 102                 }
 103         }
 104 }
 105
 106 #endif