libcc1/findcomp.cc

   1 /* Find the correct compiler.
   2    Copyright (C) 2014-2021 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include <config.h>
  21 #include <string>
  22 #include <dirent.h>
  23 #include <stdlib.h>
  24
  25 #include "libiberty.h"
  26 #include "xregex.h"
  27 #include "findcomp.hh"
  28 #include "system.h"
  29
  30 class scanner
  31 {
  32 public:
  33
  34   scanner (const std::string &dir)
  35   {
  36     m_dir = opendir (dir.c_str ());
  37   }
  38
  39   ~scanner ()
  40   {
  41     if (m_dir != NULL)
  42       closedir (m_dir);
  43   }
  44
  45   const char *next ()
  46   {
  47     if (m_dir == NULL)
  48       return NULL;
  49
  50     struct dirent *entry = readdir (m_dir);
  51     if (entry == NULL)
  52       return NULL;
  53
  54     return entry->d_name;
  55   }
  56
  57 private:
  58
  59   DIR *m_dir;
  60 };
  61
  62 static bool
  63 search_dir (const regex_t &regexp, const std::string &dir, std::string *result)
  64 {
  65   scanner scan (dir);
  66   const char *filename;
  67
  68   while ((filename = scan.next ()) != NULL)
  69     {
  70       if (regexec (&regexp, filename, 0, NULL, 0) == 0)
  71         {
  72           *result = dir + DIR_SEPARATOR + filename;
  73           return true;
  74         }
  75     }
  76
  77   return false;
  78 }
  79
  80 class tokenizer
  81 {
  82 public:
  83
  84   tokenizer (const char *str)
  85     : m_str (str),
  86       m_pos (0)
  87   {
  88   }
  89
  90   bool done () const
  91   {
  92     return m_pos == std::string::npos;
  93   }
  94
  95   std::string next ()
  96   {
  97     std::string::size_type last_pos = m_pos;
  98     std::string::size_type colon = m_str.find(':', last_pos);
  99
 100     std::string result;
 101     if (colon == std::string::npos)
 102       {
 103         m_pos = colon;
 104         result = m_str.substr(last_pos, colon);
 105       }
 106     else
 107       {
 108         m_pos = colon + 1;
 109         result = m_str.substr(last_pos, colon - last_pos);
 110       }
 111     if (result == "")
 112       result = ".";
 113
 114     return result;
 115   }
 116
 117 private:
 118
 119   std::string m_str;
 120   std::string::size_type m_pos;
 121 };
 122
 123 bool
 124 find_compiler (const regex_t &regexp, std::string *result)
 125 {
 126   const char *cpath = getenv ("PATH");
 127
 128   if (cpath == NULL)
 129     return false;
 130
 131   tokenizer dirs (cpath);
 132   while (!dirs.done ())
 133     {
 134       std::string dir = dirs.next ();
 135       if (search_dir (regexp, dir, result))
 136         return true;
 137     }
 138
 139   return false;
 140 }