src/location.c

   1 /* Locations for Bison
   2
   3    Copyright (C) 2002, 2005-2012 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 <http://www.gnu.org/licenses/>.  */
  19
  20 #include <config.h>
  21 #include "system.h"
  22
  23 #include <mbswidth.h>
  24 #include <quotearg.h>
  25
  26 #include "complain.h"
  27 #include "location.h"
  28
  29 location const empty_location = EMPTY_LOCATION_INIT;
  30
  31 /* If BUF is null, add BUFSIZE (which in this case must be less than
  32    INT_MAX) to COLUMN; otherwise, add mbsnwidth (BUF, BUFSIZE, 0) to
  33    COLUMN.  If an overflow occurs, or might occur but is undetectable,
  34    return INT_MAX.  Assume COLUMN is nonnegative.  */
  35
  36 static inline int
  37 add_column_width (int column, char const *buf, size_t bufsize)
  38 {
  39   size_t width;
  40   unsigned int remaining_columns = INT_MAX - column;
  41
  42   if (buf)
  43     {
  44       if (INT_MAX / 2 <= bufsize)
  45         return INT_MAX;
  46       width = mbsnwidth (buf, bufsize, 0);
  47     }
  48   else
  49     width = bufsize;
  50
  51   return width <= remaining_columns ? column + width : INT_MAX;
  52 }
  53
  54 /* Set *LOC and adjust scanner cursor to account for token TOKEN of
  55    size SIZE.  */
  56
  57 void
  58 location_compute (location *loc, boundary *cur, char const *token, size_t size)
  59 {
  60   int line = cur->line;
  61   int column = cur->column;
  62   char const *p0 = token;
  63   char const *p = token;
  64   char const *lim = token + size;
  65
  66   loc->start = *cur;
  67
  68   for (p = token; p < lim; p++)
  69     switch (*p)
  70       {
  71       case '\n':
  72         line += line < INT_MAX;
  73         column = 1;
  74         p0 = p + 1;
  75         break;
  76
  77       case '\t':
  78         column = add_column_width (column, p0, p - p0);
  79         column = add_column_width (column, NULL, 8 - ((column - 1) & 7));
  80         p0 = p + 1;
  81         break;
  82
  83       default:
  84         break;
  85       }
  86
  87   cur->line = line;
  88   cur->column = column = add_column_width (column, p0, p - p0);
  89
  90   loc->end = *cur;
  91
  92   if (line == INT_MAX && loc->start.line != INT_MAX)
  93     complain (loc, Wother, _("line number overflow"));
  94   if (column == INT_MAX && loc->start.column != INT_MAX)
  95     complain (loc, Wother, _("column number overflow"));
  96 }
  97
  98
  99 /* Output to OUT the location LOC.
 100    Warning: it uses quotearg's slot 3.  */
 101 unsigned
 102 location_print (FILE *out, location loc)
 103 {
 104   unsigned res = 0;
 105   int end_col = 0 != loc.end.column ? loc.end.column - 1 : 0;
 106   res += fprintf (out, "%s",
 107                   quotearg_n_style (3, escape_quoting_style, loc.start.file));
 108   if (0 <= loc.start.line)
 109     {
 110       res += fprintf (out, ":%d", loc.start.line);
 111       if (0 <= loc.start.column)
 112         res += fprintf (out, ".%d", loc.start.column);
 113     }
 114   if (loc.start.file != loc.end.file)
 115     {
 116       res += fprintf (out, "-%s",
 117                       quotearg_n_style (3, escape_quoting_style,
 118                                         loc.end.file));
 119       if (0 <= loc.end.line)
 120         {
 121           res += fprintf (out, ":%d", loc.end.line);
 122           if (0 <= end_col)
 123             res += fprintf (out, ".%d", end_col);
 124         }
 125     }
 126   else if (0 <= loc.end.line)
 127     {
 128       if (loc.start.line < loc.end.line)
 129         {
 130           res += fprintf (out, "-%d", loc.end.line);
 131           if (0 <= end_col)
 132             res += fprintf (out, ".%d", end_col);
 133         }
 134       else if (0 <= end_col && loc.start.column < end_col)
 135         res += fprintf (out, "-%d", end_col);
 136     }
 137
 138   return res;
 139 }
 140
 141
 142 /* Persistant data used by location_caret to avoid reopening and rereading the
 143    same file all over for each error.  */
 144 struct caret_info
 145 {
 146   FILE *source;
 147   size_t line;
 148   size_t offset;
 149 };
 150
 151 static struct caret_info caret_info = { NULL, 1, 0 };
 152
 153 void
 154 cleanup_caret ()
 155 {
 156   if (caret_info.source)
 157     fclose (caret_info.source);
 158 }
 159
 160 void
 161 location_caret (FILE *out, location loc)
 162 {
 163   /* FIXME: find a way to support multifile locations, and only open once each
 164      file. That would make the procedure future-proof.  */
 165   if (! (caret_info.source
 166          || (caret_info.source = fopen (loc.start.file, "r")))
 167       || loc.start.column == -1 || loc.start.line == -1)
 168     return;
 169
 170   /* If the line we want to quote is seekable (the same line as the previous
 171      location), just seek it. If it was before, we lost track of it, so
 172      return to the start of file.  */
 173   if (caret_info.line <= loc.start.line)
 174     fseek (caret_info.source, caret_info.offset, SEEK_SET);
 175   else
 176     {
 177       caret_info.line = 1;
 178       caret_info.offset = 0;
 179       fseek (caret_info.source, caret_info.offset, SEEK_SET);
 180     }
 181
 182   /* Advance to the line's position, keeping track of the offset.  */
 183   while (caret_info.line < loc.start.line)
 184     caret_info.line += fgetc (caret_info.source) == '\n';
 185   caret_info.offset = ftell (caret_info.source);
 186
 187   /* Read the actual line.  Don't update the offset, so that we keep a pointer
 188      to the start of the line.  */
 189   {
 190     char *buf = NULL;
 191     size_t size = 0;
 192     ssize_t len = getline (&buf, &size, caret_info.source);
 193     if (0 < len)
 194       {
 195         /* The caret of a multiline location ends with the first line.  */
 196         int end = loc.start.line != loc.end.line ? len : loc.end.column;
 197
 198         /* Quote the file, indent by a single column.  */
 199         fputc (' ', out);
 200         fwrite (buf, 1, len, out);
 201
 202         /* Print the caret, with the same indent as above.  */
 203         fprintf (out, " %*s", loc.start.column - 1, "");
 204         {
 205           int i = loc.start.column;
 206           do
 207             fputc ('^', out);
 208           while (++i < end);
 209         }
 210         fputc ('\n', out);
 211       }
 212     free (buf);
 213   }
 214 }
 215
 216 void
 217 boundary_set_from_string (boundary *bound, char *loc_str)
 218 {
 219   /* Must search in reverse since the file name field may
 220    * contain `.' or `:'.  */
 221   char *delim = strrchr (loc_str, '.');
 222   aver (delim);
 223   *delim = '\0';
 224   bound->column = atoi (delim+1);
 225   delim = strrchr (loc_str, ':');
 226   aver (delim);
 227   *delim = '\0';
 228   bound->line = atoi (delim+1);
 229   bound->file = uniqstr_new (loc_str);
 230 }