util.cc

   1 /*
   2  * Copyright (c) 2021, S. Gilles <sgilles@sgilles.net>
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software
   5  * for any purpose with or without fee is hereby granted, provided
   6  * that the above copyright notice and this permission notice appear
   7  * in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
  10  * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
  11  * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
  12  * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
  13  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
  14  * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
  15  * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
  16  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18 #include "util.hh"
  19
  20 #include <fstream>
  21 #include <iostream>
  22
  23 /* Find the right "~/.data/sispare" or "~/.sispare" or something */
  24 std::filesystem::path
  25 Util::find_data_dir()
  26 {
  27         char *xdg_data_home = getenv("XDG_DATA_HOME");
  28
  29         if (xdg_data_home) {
  30                 return std::filesystem::path(xdg_data_home) / "sispare";
  31         }
  32
  33         char *home = getenv("HOME");
  34
  35         if (home) {
  36                 return std::filesystem::path(home) / ".sispare";
  37         }
  38
  39         throw std::runtime_error("You have no $HOME. I give up.");
  40 }
  41
  42 /* Print exception, maybe with stack trace */
  43 void
  44 Util::output_nested_ex(const std::exception& ex, int level)
  45 {
  46         if (level == 0) {
  47                 std::cerr << "Error:" << std::endl;
  48         }
  49
  50         std::cerr << std::string(level, '.') << ex.what() << std::endl;
  51         try {
  52                 std::rethrow_if_nested(ex);
  53         } catch (const std::exception& ex2) {
  54                 output_nested_ex(ex2, level + 1);
  55         } catch (...) {}
  56 }
  57
  58 /* Slurp file into string (for reading A/B sides). throws on failure */
  59 std::string
  60 Util::slurp(const std::filesystem::path& path)
  61 {
  62         std::ifstream ii(path, std::ios::in | std::ios::binary);
  63
  64         if (ii) {
  65                 std::string slurped;
  66
  67                 ii.seekg(0, std::ios::end);
  68                 slurped.resize(ii.tellg());
  69                 ii.seekg(0, std::ios::beg);
  70                 ii.read(&slurped[0], slurped.size());
  71                 ii.close();
  72
  73                 /* Remove trailing newline */
  74                 if (std::isspace(slurped.back())) {
  75                         slurped.pop_back();
  76                 }
  77
  78                 return slurped;
  79         }
  80
  81         std::ostringstream err;
  82
  83         err << "Cannot read " << path;
  84         throw std::runtime_error(err.str());
  85 }