src/fixits.c

   1 /* Support for fixing grammar files.
   2
   3    Copyright (C) 2019-2021 Free Software Foundation, Inc.
   4
   5    This file is part of Bison, the GNU Compiler Compiler.
   6
   7    This program is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation, either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  19
  20 #include <config.h>
  21
  22 #include "fixits.h"
  23
  24 #include <error.h>
  25 #include <get-errno.h>
  26 #include <gl_array_list.h>
  27 #include <gl_xlist.h>
  28 #include <progname.h>
  29 #include <quote.h>
  30 #include <quotearg.h>
  31 #include <vasnprintf.h>
  32
  33 #include "system.h"
  34
  35 #include "files.h"
  36 #include "getargs.h"
  37
  38 typedef struct
  39 {
  40   location location;
  41   char *fix;
  42 } fixit;
  43
  44 gl_list_t fixits = NULL;
  45
  46 static fixit *
  47 fixit_new (location const *loc, char const* fix)
  48 {
  49   fixit *res = xmalloc (sizeof *res);
  50   res->location = *loc;
  51   res->fix = xstrdup (fix);
  52   return res;
  53 }
  54
  55 static int
  56 fixit_cmp (const  fixit *a, const fixit *b)
  57 {
  58   return location_cmp (a->location, b->location);
  59 }
  60
  61 static void
  62 fixit_free (fixit *f)
  63 {
  64   free (f->fix);
  65   free (f);
  66 }
  67
  68
  69 /* GCC and Clang follow the same pattern.
  70    https://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Message-Formatting-Options.html
  71    https://clang.llvm.org/docs/UsersManual.html#cmdoption-fdiagnostics-parseable-fixits */
  72 static void
  73 fixit_print (fixit const *f, FILE *out)
  74 {
  75   fprintf (out, "fix-it:%s:{%d:%d-%d:%d}:%s\n",
  76            quotearg_n_style (1, c_quoting_style, f->location.start.file),
  77            f->location.start.line, f->location.start.byte,
  78            f->location.end.line, f->location.end.byte,
  79            quotearg_n_style (2, c_quoting_style, f->fix));
  80 }
  81
  82
  83 void
  84 fixits_register (location const *loc, char const* fix)
  85 {
  86   if (!fixits)
  87     fixits = gl_list_create_empty (GL_ARRAY_LIST,
  88                                    /* equals */ NULL,
  89                                    /* hashcode */ NULL,
  90                                    (gl_listelement_dispose_fn) fixit_free,
  91                                    true);
  92   fixit *f = fixit_new (loc, fix);
  93   gl_sortedlist_add (fixits, (gl_listelement_compar_fn) fixit_cmp, f);
  94   if (feature_flag & feature_fixit)
  95     fixit_print (f, stderr);
  96 }
  97
  98
  99 bool
 100 fixits_empty (void)
 101 {
 102   return !fixits;
 103 }
 104
 105
 106 void
 107 fixits_run (void)
 108 {
 109   if (!fixits)
 110     return;
 111
 112   /* This is not unlike what is done in location_caret.  */
 113   uniqstr input = ((fixit *) gl_list_get_at (fixits, 0))->location.start.file;
 114   /* Backup the file. */
 115   char buf[256];
 116   size_t len = sizeof (buf);
 117   char *backup = asnprintf (buf, &len, "%s~", input);
 118   if (!backup)
 119     xalloc_die ();
 120   if (rename (input, backup))
 121     error (EXIT_FAILURE, get_errno (),
 122            _("%s: cannot backup"), quotearg_colon (input));
 123   FILE *in = xfopen (backup, "r");
 124   FILE *out = xfopen (input, "w");
 125   size_t line = 1;
 126   size_t offset = 1;
 127   void const *p = NULL;
 128   gl_list_iterator_t iter = gl_list_iterator (fixits);
 129   while (gl_list_iterator_next (&iter, &p, NULL))
 130     {
 131       fixit const *f = p;
 132       /* Look for the correct line. */
 133       while (line < f->location.start.line)
 134         {
 135           int c = getc (in);
 136           if (c == EOF)
 137             break;
 138           if (c == '\n')
 139             {
 140               ++line;
 141               offset = 1;
 142             }
 143           putc (c, out);
 144         }
 145
 146       /* Look for the right offset. */
 147       bool need_eol = false;
 148       while (offset < f->location.start.byte)
 149         {
 150           int c = getc (in);
 151           if (c == EOF)
 152             break;
 153           ++offset;
 154           if (c == '\n')
 155             /* The position we are asked for is beyond the actual
 156                line: pad with spaces, and remember we need a \n.  */
 157             need_eol = true;
 158           putc (need_eol ? ' ' : c, out);
 159         }
 160
 161       /* Paste the fix instead. */
 162       fputs (f->fix, out);
 163
 164       /* Maybe install the eol afterwards.  */
 165       if (need_eol)
 166         putc ('\n', out);
 167
 168       /* Skip the bad input. */
 169       while (line < f->location.end.line)
 170         {
 171           int c = getc (in);
 172           if (c == EOF)
 173             break;
 174           if (c == '\n')
 175             {
 176               ++line;
 177               offset = 1;
 178             }
 179         }
 180       while (offset < f->location.end.byte)
 181         {
 182           int c = getc (in);
 183           if (c == EOF)
 184             break;
 185           ++offset;
 186         }
 187
 188       /* If erasing the content of a full line, also remove the
 189          end-of-line. */
 190       if (f->fix[0] == 0 && f->location.start.byte == 1)
 191         {
 192           int c = getc (in);
 193           if (c == EOF)
 194             break;
 195           else if (c == '\n')
 196             {
 197               ++line;
 198               offset = 1;
 199             }
 200           else
 201             ungetc (c, in);
 202         }
 203     }
 204   /* Paste the rest of the file.  */
 205   {
 206     int c;
 207     while ((c = getc (in)) != EOF)
 208       putc (c, out);
 209   }
 210
 211   gl_list_iterator_free (&iter);
 212   xfclose (out);
 213   xfclose (in);
 214   fprintf (stderr, "%s: file %s was updated (backup: %s)\n",
 215            program_name, quote_n (0, input), quote_n (1, backup));
 216   if (backup != buf)
 217     free (backup);
 218 }
 219
 220
 221 /* Free the registered fixits.  */
 222 void fixits_free (void)
 223 {
 224   if (fixits)
 225     {
 226       gl_list_free (fixits);
 227       fixits = NULL;
 228     }
 229 }