xapian-core/common/fd.h

   1 /** @file
   2  * @brief Wrapper class around a file descriptor to avoid leaks
   3  */
   4 /* Copyright (C) 2011,2012 Olly Betts
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to
   8  * deal in the Software without restriction, including without limitation the
   9  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  10  * sell copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  22  * IN THE SOFTWARE.
  23  */
  24
  25 #ifndef XAPIAN_INCLUDED_FD_H
  26 #define XAPIAN_INCLUDED_FD_H
  27
  28 #include "safeunistd.h"
  29
  30 class FD {
  31     int fd;
  32
  33     /// Prevent copying.
  34     FD(const FD&) = delete;
  35
  36     /// Prevent assignment between FD objects.
  37     FD& operator=(const FD&) = delete;
  38
  39   public:
  40     FD() : fd(-1) { }
  41
  42     FD(int fd_) : fd(fd_) { }
  43
  44     ~FD() { if (fd != -1) ::close(fd); }
  45
  46     FD& operator=(int fd_) {
  47         if (fd != -1) ::close(fd);
  48         fd = fd_;
  49         return *this;
  50     }
  51
  52     operator int() const { return fd; }
  53
  54     int close() {
  55         // Don't check for -1 here, so that close(FD) sets errno as close(int)
  56         // would.
  57         int fd_to_close = fd;
  58         fd = -1;
  59         return ::close(fd_to_close);
  60     }
  61 };
  62
  63 inline int close(FD& fd) {
  64     return fd.close();
  65 }
  66
  67 #endif