More missing stuff...

git-svn-id: svn://localhost/ardour2/trunk@2645 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/glibmm2/examples/iochannel_stream/fdstream.h

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+/* Copyright (C) 2004 The glibmm Development Team
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free
+ * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/*
+ * The fdstream/fdstreambuf example classes provide a streambuffer
+ * interface for Glib::IOChannel, so that standard iostreams can be
+ * used with fifos, pipes and sockets, with safe temporary files
+ * opened with mkstemp() and with files opened with other system
+ * functions such as Unix open().
+ * 
+ * It does not make use of the Glib::IOChannel automatic charset code
+ * conversion facilities (which when enabled will convert from UTF-8
+ * to the locale codeset when writing out, and vice-versa when reading
+ * in).  Such automatic codeset conversion is usually undesirable as
+ * it makes the target file unportable - a file written out in the
+ * locale charset can only be used by those expecting the same locale
+ * codeset.  It is also unnecessary as the <<() and >>() operators for
+ * Glib::ustring already carry out this codeset conversion (to avoid
+ * this use Glib::ustring::raw() when writing out to a stream via
+ * operator <<(), and read in via a std::string object with operator
+ * >>()).
+ *
+ * If an automatic codeset conversion option is thought to be
+ * valuable, it would be possible to provide this by having a read
+ * buffer in fdstreambuf large enough to take and putback six bytes
+ * (the largest space occupied by a UTF-8 character).  This would
+ * require rewriting fdstreambuf::underflow(), but in compensation
+ * fdstreambuf::xsgetn() could be omitted, as if a read buffer were
+ * provided then std::streambuf::xsgetn() would be adequate for the
+ * purpose by itself.
+ *
+ * A serious implementation would probably also provide separate
+ * read-only ifdstream classes and write-only ofdstream classes, as
+ * fdstream provides both read and write facilities.
+*/
+
+
+#ifndef GLIBMMEXAMPLE_FDSTREAM_H
+#define GLIBMMEXAMPLE_FDSTREAM_H
+
+#include <istream>
+#include <ostream>
+#include <streambuf>
+#include <glibmm/iochannel.h>
+
+struct fdstream_error
+{
+  bool error;
+  Glib::IOChannelError::Code code;  
+};
+
+class fdstreambuf: public std::streambuf
+{
+public:
+  fdstreambuf(int fd, bool manage);
+  fdstreambuf();
+  ~fdstreambuf();
+
+  void create_iochannel(int fd, bool manage);
+  void detach_fd();
+  void close_iochannel();
+  void connect(const sigc::slot<bool, Glib::IOCondition>& callback, Glib::IOCondition condition);
+  fdstream_error get_error() const;
+
+protected:
+  virtual int_type underflow();
+  virtual std::streamsize xsgetn(char* dest, std::streamsize num);
+  virtual int sync();
+  virtual int_type overflow(int_type c);
+  virtual std::streamsize xsputn(const char* source, std::streamsize num);
+
+private:
+  Glib::RefPtr<Glib::IOChannel> iochannel_;
+  fdstream_error error_condition;
+
+  // putback_buffer does not do any buffering: it reserves one character
+  // for putback and one character for a peek() and/or for bumping
+  // with sbumpc/uflow()
+  char putback_buffer[2];
+
+  void reset();
+};
+
+class fdstream : 
+  public std::istream, 
+  public std::ostream
+{
+public:
+
+  explicit fdstream(int fd, bool manage = true);
+  fdstream();
+
+  // If fdstream is managing a file descriptor, attaching a new
+  // one will close the old one - call detach() to unmanage it
+  void attach(int fd, bool manage = true);
+  void detach();
+
+  void close();
+  void connect(const sigc::slot<bool, Glib::IOCondition>& callback,
+	       Glib::IOCondition condition);
+  fdstream_error get_error() const;
+
+private:
+  fdstreambuf buf;
+};
+
+#endif /*GLIBMMEXAMPLE_FDSTREAM_H*/