include/wx/unix/pipe.h

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/unix/pipe.h
   3 // Purpose:     wxPipe class
   4 // Author:      Vadim Zeitlin
   5 // Modified by:
   6 // Created:     24.06.2003 (extracted from src/unix/utilsunx.cpp)
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 2003 Vadim Zeitlin <vadim@wxwidgets.org>
   9 // Licence:     wxWindows licence
  10 ///////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_UNIX_PIPE_H_
  13 #define _WX_UNIX_PIPE_H_
  14
  15 #include <unistd.h>
  16
  17 #include "wx/log.h"
  18 #include "wx/intl.h"
  19
  20 // ----------------------------------------------------------------------------
  21 // wxPipe: this class encapsulates pipe() system call
  22 // ----------------------------------------------------------------------------
  23
  24 class wxPipe
  25 {
  26 public:
  27     // the symbolic names for the pipe ends
  28     enum Direction
  29     {
  30         Read,
  31         Write
  32     };
  33
  34     enum
  35     {
  36         INVALID_FD = -1
  37     };
  38
  39     // default ctor doesn't do anything
  40     wxPipe() { m_fds[Read] = m_fds[Write] = INVALID_FD; }
  41
  42     // create the pipe, return TRUE if ok, FALSE on error
  43     bool Create()
  44     {
  45         if ( pipe(m_fds) == -1 )
  46         {
  47             wxLogSysError(_("Pipe creation failed"));
  48
  49             return false;
  50         }
  51
  52         return true;
  53     }
  54
  55     // switch the given end of the pipe to non-blocking IO
  56     bool MakeNonBlocking(Direction which)
  57     {
  58         const int flags = fcntl(m_fds[which], F_GETFL, 0);
  59         if ( flags == -1 )
  60             return false;
  61
  62         return fcntl(m_fds[which], F_SETFL, flags | O_NONBLOCK) == 0;
  63     }
  64
  65     // return TRUE if we were created successfully
  66     bool IsOk() const { return m_fds[Read] != INVALID_FD; }
  67
  68     // return the descriptor for one of the pipe ends
  69     int operator[](Direction which) const { return m_fds[which]; }
  70
  71     // detach a descriptor, meaning that the pipe dtor won't close it, and
  72     // return it
  73     int Detach(Direction which)
  74     {
  75         int fd = m_fds[which];
  76         m_fds[which] = INVALID_FD;
  77
  78         return fd;
  79     }
  80
  81     // close the pipe descriptors
  82     void Close()
  83     {
  84         for ( size_t n = 0; n < WXSIZEOF(m_fds); n++ )
  85         {
  86             if ( m_fds[n] != INVALID_FD )
  87             {
  88                 close(m_fds[n]);
  89                 m_fds[n] = INVALID_FD;
  90             }
  91         }
  92     }
  93
  94     // dtor closes the pipe descriptors
  95     ~wxPipe() { Close(); }
  96
  97 private:
  98     int m_fds[2];
  99 };
 100
 101 #if wxUSE_STREAMS && wxUSE_FILE
 102
 103 #include "wx/wfstream.h"
 104
 105 // ----------------------------------------------------------------------------
 106 // wxPipeInputStream: stream for reading from a pipe
 107 // ----------------------------------------------------------------------------
 108
 109 class wxPipeInputStream : public wxFileInputStream
 110 {
 111 public:
 112     wxPipeInputStream(int fd) : wxFileInputStream(fd) { }
 113
 114     // return TRUE if the pipe is still opened
 115     bool IsOpened() const { return !Eof(); }
 116
 117     // return TRUE if we have anything to read, don't block
 118     virtual bool CanRead() const;
 119 };
 120
 121 // ----------------------------------------------------------------------------
 122 // wxPipeOutputStream: stream for writing to a pipe
 123 // ----------------------------------------------------------------------------
 124
 125 class wxPipeOutputStream : public wxFileOutputStream
 126 {
 127 public:
 128     wxPipeOutputStream(int fd) : wxFileOutputStream(fd) { }
 129
 130     // Override the base class version to ignore "pipe full" errors: this is
 131     // not an error for this class.
 132     size_t OnSysWrite(const void *buffer, size_t size);
 133 };
 134
 135 #endif // wxUSE_STREAMS && wxUSE_FILE
 136
 137 #endif // _WX_UNIX_PIPE_H_
 138