src/libpspp/temp-file.c

   1 /* PSPP - a program for statistical analysis.
   2    Copyright (C) 2010, 2011 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
  16
  17 /* Functions for temporary files that honor $TMPDIR. */
  18
  19 #include <config.h>
  20
  21 #include "libpspp/temp-file.h"
  22 #include "libpspp/hmapx.h"
  23 #include "libpspp/hash-functions.h"
  24
  25 #include <stdlib.h>
  26
  27 #include "gl/clean-temp.h"
  28 #include "gl/xvasprintf.h"
  29
  30 /* Creates and returns a new temporary file that will be removed automatically
  31    when the process exits.  The file is opened in mode "wb+".  To close the
  32    file before the process exits, use close_temp_file() to ensure that it gets
  33    deleted early.
  34
  35    Returns NULL if creating the temporary file fails.
  36
  37    This is similar to tmpfile(), except:
  38
  39      - It honors the $TMPDIR environment variable.
  40
  41 */
  42
  43 static void cleanup (void);
  44
  45 static struct temp_dir *temp_dir;
  46 static struct hmapx map;
  47
  48 static void
  49 setup (void)
  50 {
  51   hmapx_init (&map);
  52   temp_dir = create_temp_dir ("pspp", NULL, true);
  53 }
  54
  55 static void
  56 initialise (void)
  57 {
  58   if (temp_dir == NULL)
  59     {
  60       setup ();
  61       if (temp_dir == NULL)
  62         return ;
  63       atexit (cleanup);
  64     }
  65 }
  66
  67
  68 const char *
  69 temp_dir_name (void)
  70 {
  71   initialise ();
  72
  73   if (temp_dir)
  74     return temp_dir->dir_name;
  75
  76   return NULL;
  77 }
  78
  79 static void
  80 cleanup (void)
  81 {
  82   struct hmapx_node *node;
  83   char *fn;
  84
  85   cleanup_temp_dir (temp_dir);
  86
  87   HMAPX_FOR_EACH (fn, node, &map)
  88     {
  89       free (fn);
  90     }
  91
  92   hmapx_destroy (&map);
  93 }
  94
  95 FILE *
  96 create_temp_file (void)
  97 {
  98   static int idx = 0;
  99   char *file_name;
 100   FILE *stream;
 101
 102   initialise ();
 103   if (temp_dir == NULL)
 104     return NULL;
 105
 106   file_name = xasprintf ("%s/%d", temp_dir->dir_name, idx++);
 107   register_temp_file (temp_dir, file_name);
 108   stream = fopen_temp (file_name, "wb+", true);
 109   if (stream == NULL)
 110     unregister_temp_file (temp_dir, file_name);
 111   else
 112     setvbuf (stream, NULL, _IOFBF, 65536);
 113
 114   hmapx_insert (&map, file_name, hash_pointer (stream, 0));
 115
 116   return stream;
 117 }
 118
 119 /* Closes and removes a temporary file created by create_temp_file(). */
 120 void
 121 close_temp_file (FILE *file)
 122 {
 123   if (file != NULL)
 124     {
 125       struct hmapx_node *node = hmapx_first_with_hash (&map, hash_pointer (file, 0));
 126       char *fn = node->data;
 127       fclose_temp (file);
 128       cleanup_temp_file (temp_dir, fn);
 129       hmapx_delete (&map, node);
 130       free (fn);
 131     }
 132 }