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panda/src/downloader/multiplexStreamBuf.cxx

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// Filename: multiplexStreamBuf.cxx
// Created by:  drose (27Nov00)
//
////////////////////////////////////////////////////////////////////
//
// PANDA 3D SOFTWARE
// Copyright (c) 2001, Disney Enterprises, Inc.  All rights reserved
//
// All use of this software is subject to the terms of the Panda 3d
// Software license.  You should have received a copy of this license
// along with this source code; you will also find a current copy of
// the license at http://www.panda3d.org/license.txt .
//
// To contact the maintainers of this program write to
// panda3d@yahoogroups.com .
//
////////////////////////////////////////////////////////////////////

#include "multiplexStreamBuf.h"

#if defined(WIN32_VC)
#define WINDOWS_LEAN_AND_MEAN
#include <windows.h>
#undef WINDOWS_LEAN_AND_MEAN
#endif

// We use real assert() instead of nassert(), because we're likely
// to be invoked directly by notify here, and we don't want to
// risk infinite recursion.
#include <assert.h>

#ifndef HAVE_STREAMSIZE
// Some compilers--notably SGI--don't define this for us.
typedef int streamsize;
#endif

////////////////////////////////////////////////////////////////////
//     Function: MultiplexStreamBuf::Output::close
//       Access: Public
//  Description: Closes or deletes the relevant pointers, if _owns_obj
//               is true.
////////////////////////////////////////////////////////////////////
void MultiplexStreamBuf::Output::
close() {
  if (_owns_obj) {
    switch (_output_type) {
    case OT_ostream:
      assert(_out != (ostream *)NULL);
      delete _out;
      break;

    case OT_stdio:
      assert(_fout != (FILE *)NULL);
      fclose(_fout);
      break;

    default:
      break;
    }
  }
}

////////////////////////////////////////////////////////////////////
//     Function: MultiplexStreamBuf::Output::write_string
//       Access: Public
//  Description: Dumps the indicated string to the appropriate place.
////////////////////////////////////////////////////////////////////
void MultiplexStreamBuf::Output::
write_string(const string &str) {
  switch (_output_type) {
  case OT_ostream:
    assert(_out != (ostream *)NULL);
    _out->write(str.data(), str.length());
    _out->flush();
    break;

  case OT_stdio:
    assert(_fout != (FILE *)NULL);
    fwrite(str.data(), str.length(), 1, _fout);
    fflush(_fout);
    break;

  case OT_system_debug:
#ifdef WIN32_VC
    OutputDebugString(str.c_str());
#endif
    break;
  }
}

////////////////////////////////////////////////////////////////////
//     Function: MultiplexStreamBuf::Constructor
//       Access: Public
//  Description:
////////////////////////////////////////////////////////////////////
MultiplexStreamBuf::
MultiplexStreamBuf() {
#ifndef HAVE_IOSTREAM
  // Older iostream implementations required this.
  allocate();
  setp(base(), ebuf());
#endif
}

////////////////////////////////////////////////////////////////////
//     Function: MultiplexStreamBuf::Destructor
//       Access: Public, Virtual
//  Description:
////////////////////////////////////////////////////////////////////
MultiplexStreamBuf::
~MultiplexStreamBuf() {
  sync();

  // Make sure all of our owned pointers are freed.
  Outputs::iterator oi;
  for (oi = _outputs.begin(); oi != _outputs.end(); ++oi) {
    Output &out = (*oi);
    out.close();
  }
}

////////////////////////////////////////////////////////////////////
//     Function: MultiplexStreamBuf::add_output
//       Access: Public
//  Description: Adds the indicated output destinition to the set of
//               things that will be written to when characters are
//               output to the MultiplexStream.
////////////////////////////////////////////////////////////////////
void MultiplexStreamBuf::
add_output(MultiplexStreamBuf::BufferType buffer_type,
           MultiplexStreamBuf::OutputType output_type,
           ostream *out, FILE *fout, bool owns_obj) {
#ifdef OLD_HAVE_IPC
  // Ensure that we have the mutex while we fiddle with the list of
  // outputs.
  mutex_lock m(_lock);
#endif

  Output o;
  o._buffer_type = buffer_type;
  o._output_type = output_type;
  o._out = out;
  o._fout = fout;
  o._owns_obj = owns_obj;
  _outputs.push_back(o);
}


////////////////////////////////////////////////////////////////////
//     Function: MultiplexStreamBuf::flush
//       Access: Public
//  Description: Forces out all output that hasn't yet been written.
////////////////////////////////////////////////////////////////////
void MultiplexStreamBuf::
flush() {
#ifdef OLD_HAVE_IPC
  mutex_lock m(_lock);
#endif

  write_chars("", 0, true);
}

////////////////////////////////////////////////////////////////////
//     Function: MultiplexStreamBuf::overflow
//       Access: Public, Virtual
//  Description: Called by the system ostream implementation when its
//               internal buffer is filled, plus one character.
////////////////////////////////////////////////////////////////////
int MultiplexStreamBuf::
overflow(int ch) {
#ifdef OLD_HAVE_IPC
  mutex_lock m(_lock);
#endif

  streamsize n = pptr() - pbase();

  if (n != 0) {
    write_chars(pbase(), n, false);
    pbump(-n);  // Reset pptr().
  }

  if (ch != EOF) {
    // Write one more character.
    char c = ch;
    write_chars(&c, 1, false);
  }

  return 0;
}

////////////////////////////////////////////////////////////////////
//     Function: MultiplexStreamBuf::sync
//       Access: Public, Virtual
//  Description: Called by the system ostream implementation when the
//               buffer should be flushed to output (for instance, on
//               destruction).
////////////////////////////////////////////////////////////////////
int MultiplexStreamBuf::
sync() {
#ifdef OLD_HAVE_IPC
  mutex_lock m(_lock);
#endif

  streamsize n = pptr() - pbase();

  // We pass in false for the flush value, even though our
  // transmitting ostream said to sync.  This allows us to get better
  // line buffering, since our transmitting ostream is often set
  // unitbuf, and might call sync multiple times in one line.  We
  // still have an explicit flush() call to force the issue.
  write_chars(pbase(), n, false);
  pbump(-n);

  return 0;  // Return 0 for success, EOF to indicate write full.
}

////////////////////////////////////////////////////////////////////
//     Function: MultiplexStreamBuf::write_chars
//       Access: Private
//  Description: An internal function called by sync() and overflow()
//               to store one or more characters written to the stream
//               into the memory buffer.
//
//               It is assumed that there is only one thread at a time
//               running this code; it is the responsibility of the
//               caller to grab the _lock mutex before calling this.
////////////////////////////////////////////////////////////////////
void MultiplexStreamBuf::
write_chars(const char *start, int length, bool flush) {
  size_t orig = _line_buffer.length();
  string latest;
  if (length != 0) {
    latest = string(start, length);
  }
  string line;

  if (flush) {
    // If we're to flush the stream now, we dump the whole thing
    // regardless of whether we have reached end-of-line.
    line = _line_buffer + latest;
    _line_buffer = "";

  } else {
    // Otherwise, we check for the end-of-line character, for our
    // ostreams that only want a complete line at a time.
    _line_buffer += latest;
    size_t eol = _line_buffer.rfind('\n', orig);
    if (eol != string::npos) {
      line = _line_buffer.substr(0, eol + 1);
      _line_buffer = _line_buffer.substr(eol + 1);
    }
  }

  Outputs::iterator oi;
  for (oi = _outputs.begin(); oi != _outputs.end(); ++oi) {
    Output &out = (*oi);
    switch (out._buffer_type) {
    case BT_none:
      // No buffering: send all new characters directly to the ostream.
      if (!latest.empty()) {
        out.write_string(latest);
      }
      break;

    case BT_line:
      // Line buffering: send only when a complete line has been
      // received.
      if (!line.empty()) {
        out.write_string(line);
      }
      break;
    }
  }

}

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