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src/libdar/tuyau.hpp
00001 /*********************************************************************/
00002 // dar - disk archive - a backup/restoration program
00003 // Copyright (C) 2002-2052 Denis Corbin
00004 //
00005 // This program is free software; you can redistribute it and/or
00006 // modify it under the terms of the GNU General Public License
00007 // as published by the Free Software Foundation; either version 2
00008 // of the License, or (at your option) any later version.
00009 //
00010 // This program is distributed in the hope that it will be useful,
00011 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00012 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00013 // GNU General Public License for more details.
00014 //
00015 // You should have received a copy of the GNU General Public License
00016 // along with this program; if not, write to the Free Software
00017 // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
00018 //
00019 // to contact the author : http://dar.linux.free.fr/email.html
00020 /*********************************************************************/
00021 // $Id$
00022 //
00023 /*********************************************************************/
00024 
00033 
00034 #ifndef TUYAU_HPP
00035 #define TUYAU_HPP
00036 
00037 #include "../my_config.h"
00038 #include "infinint.hpp"
00039 #include "generic_file.hpp"
00040 #include "thread_cancellation.hpp"
00041 
00042 namespace libdar
00043 {
00044 
00046 
00048 
00049     class tuyau : public generic_file, public thread_cancellation, protected mem_ui
00050     {
00051     public:
00052         tuyau(user_interaction & dialog,    //< for user interaction
00053               int fd);                      //< fd is the filedescriptor of a pipe extremity already openned
00054         tuyau(user_interaction & dialog,
00055               int fd,                       //< fd is the filedescriptor of a pipe extremity already openned
00056               gf_mode mode);                //< forces the mode if possible
00057         tuyau(user_interaction & dialog,    //< for user interaction
00058               const std::string &filename,  //< named pipe to open
00059               gf_mode mode);                //< forces the mode if possible
00060         tuyau(user_interaction & dialog);   //< creates a anonymous pipe and bind itself to the writing end. The reading end can be obtained by get_read_side() method
00061         ~tuyau();
00062 
00063             // provides the reading end of the anonymous pipe when the current object has created it (no filedesc, no path given to constructor).
00064             // it cannot be called more than once.
00065         int get_read_fd() const;
00066 
00068 
00072         void close_read_fd();
00073 
00075         void do_not_close_read_fd();
00076 
00077             // inherited from generic_file
00078         bool skip(const infinint & pos);
00079         bool skip_to_eof();
00080         bool skip_relative(signed int x);
00081         infinint get_position() { return position; };
00082 
00083         bool has_next_to_read();
00084 
00085     protected:
00086         virtual U_I inherited_read(char *a, U_I size);
00087         virtual void inherited_write(const char *a, U_I size);
00088         void inherited_sync_write() {};
00089         void inherited_terminate();
00090 
00091     private:
00092         enum
00093         {
00094             pipe_fd,        //< holds a single file descriptor for the pipe
00095             pipe_path,      //< holds a filename to be openned (named pipe)
00096             pipe_both       //< holds a pair of file descriptors
00097         }
00098         pipe_mode;          //< defines how the object's status (which possible values defined by the anonymous enum above)
00099         infinint position;  //< recorded position in the stream
00100         int filedesc;       //< file descriptors of the pipe
00101         int other_end_fd;   //< in pipe_both mode, this holds the reading side of the anonymous pipe
00102         std::string chemin; //< in pipe_path mode only, this holds the named pipe to be open
00103         bool has_one_to_read; //< if true, the next char to read is placed in "next_to_read"
00104         char next_to_read;  //< when has_one_to_read is true, contains the next to read byte
00105 
00106         void ouverture();
00107 
00109 
00112         bool read_and_drop(infinint byte);
00113 
00115         bool read_to_eof();
00116     };
00117 
00118 } // end of namespace
00119 
00120 #endif
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