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tuyau.hpp
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1 /*********************************************************************/
2 // dar - disk archive - a backup/restoration program
3 // Copyright (C) 2002-2052 Denis Corbin
4 //
5 // This program is free software; you can redistribute it and/or
6 // modify it under the terms of the GNU General Public License
7 // as published by the Free Software Foundation; either version 2
8 // of the License, or (at your option) any later version.
9 //
10 // This program is distributed in the hope that it will be useful,
11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 // GNU General Public License for more details.
14 //
15 // You should have received a copy of the GNU General Public License
16 // along with this program; if not, write to the Free Software
17 // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 //
19 // to contact the author : http://dar.linux.free.fr/email.html
20 /*********************************************************************/
21 
30 
31 #ifndef TUYAU_HPP
32 #define TUYAU_HPP
33 
34 #include "../my_config.h"
35 #include "infinint.hpp"
36 #include "generic_file.hpp"
37 #include "thread_cancellation.hpp"
38 
39 namespace libdar
40 {
41 
43 
45 
46  class tuyau : public generic_file, public thread_cancellation, protected mem_ui
47  {
48  public:
49  tuyau(user_interaction & dialog, //< for user interaction
50  int fd); //< fd is the filedescriptor of a pipe extremity already openned
51  tuyau(user_interaction & dialog,
52  int fd, //< fd is the filedescriptor of a pipe extremity already openned
53  gf_mode mode); //< forces the mode if possible
54  tuyau(user_interaction & dialog, //< for user interaction
55  const std::string &filename, //< named pipe to open
56  gf_mode mode); //< forces the mode if possible
57  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
58  ~tuyau();
59 
60  // provides the reading end of the anonymous pipe when the current object has created it (no filedesc, no path given to constructor).
61  // it cannot be called more than once.
62  int get_read_fd() const;
63 
65 
69  void close_read_fd();
70 
72  void do_not_close_read_fd();
73 
74  // inherited from generic_file
75  bool skip(const infinint & pos);
76  bool skip_to_eof();
77  bool skip_relative(signed int x);
78  infinint get_position() { return position; };
79 
80  bool has_next_to_read();
81 
82  protected:
83  virtual U_I inherited_read(char *a, U_I size);
84  virtual void inherited_write(const char *a, U_I size);
86  void inherited_terminate();
87 
88  private:
89  enum
90  {
91  pipe_fd, //< holds a single file descriptor for the pipe
92  pipe_path, //< holds a filename to be openned (named pipe)
93  pipe_both //< holds a pair of file descriptors
94  }
95  pipe_mode; //< defines how the object's status (which possible values defined by the anonymous enum above)
96  infinint position; //< recorded position in the stream
97  int filedesc; //< file descriptors of the pipe
98  int other_end_fd; //< in pipe_both mode, this holds the reading side of the anonymous pipe
99  std::string chemin; //< in pipe_path mode only, this holds the named pipe to be open
100  bool has_one_to_read; //< if true, the next char to read is placed in "next_to_read"
101  char next_to_read; //< when has_one_to_read is true, contains the next to read byte
102 
103  void ouverture();
104 
106 
109  bool read_and_drop(infinint byte);
110 
112  bool read_to_eof();
113  };
114 
115 } // end of namespace
116 
117 #endif