gdb/source-cache.c

   1 /* Cache of styled source file text
   2    Copyright (C) 2018-2019 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #include "defs.h"
  20 #include "source-cache.h"
  21 #include "common/scoped_fd.h"
  22 #include "source.h"
  23 #include "cli/cli-style.h"
  24
  25 #ifdef HAVE_SOURCE_HIGHLIGHT
  26 /* If Gnulib redirects 'open' and 'close' to its replacements
  27    'rpl_open' and 'rpl_close' via cpp macros, including <fstream>
  28    below with those macros in effect will cause unresolved externals
  29    when GDB is linked.  Happens, e.g., in the MinGW build.  */
  30 #undef open
  31 #undef close
  32 #include <fstream>
  33 #include <sstream>
  34 #include <srchilite/sourcehighlight.h>
  35 #include <srchilite/langmap.h>
  36 #endif
  37
  38 /* The number of source files we'll cache.  */
  39
  40 #define MAX_ENTRIES 5
  41
  42 /* See source-cache.h.  */
  43
  44 source_cache g_source_cache;
  45
  46 /* See source-cache.h.  */
  47
  48 bool
  49 source_cache::get_plain_source_lines (struct symtab *s, int first_line,
  50                                       int last_line, std::string *lines)
  51 {
  52   scoped_fd desc (open_source_file (s));
  53   if (desc.get () < 0)
  54     return false;
  55
  56   if (s->line_charpos == 0)
  57     find_source_lines (s, desc.get ());
  58
  59   if (first_line < 1 || first_line > s->nlines || last_line < 1)
  60     return false;
  61
  62   if (lseek (desc.get (), s->line_charpos[first_line - 1], SEEK_SET) < 0)
  63     perror_with_name (symtab_to_filename_for_display (s));
  64
  65   int last_charpos;
  66   if (last_line >= s->nlines)
  67     {
  68       struct stat st;
  69
  70       if (fstat (desc.get (), &st) < 0)
  71         perror_with_name (symtab_to_filename_for_display (s));
  72       /* We could cache this in line_charpos... */
  73       last_charpos = st.st_size;
  74     }
  75   else
  76     last_charpos = s->line_charpos[last_line];
  77
  78   lines->resize (last_charpos - s->line_charpos[first_line - 1]);
  79   if (myread (desc.get (), &(*lines)[0], lines->size ()) < 0)
  80     perror_with_name (symtab_to_filename_for_display (s));
  81
  82   return true;
  83 }
  84
  85 /* See source-cache.h.  */
  86
  87 std::string
  88 source_cache::extract_lines (const struct source_text &text, int first_line,
  89                              int last_line)
  90 {
  91   int lineno = 1;
  92   std::string::size_type pos = 0;
  93   std::string::size_type first_pos = std::string::npos;
  94
  95   while (pos != std::string::npos && lineno <= last_line)
  96     {
  97       std::string::size_type new_pos = text.contents.find ('\n', pos);
  98
  99       if (lineno == first_line)
 100         first_pos = pos;
 101
 102       pos = new_pos;
 103       if (lineno == last_line || pos == std::string::npos)
 104         {
 105           if (first_pos == std::string::npos)
 106             return {};
 107           if (pos == std::string::npos)
 108             pos = text.contents.size ();
 109           return text.contents.substr (first_pos, pos - first_pos);
 110         }
 111       ++lineno;
 112       ++pos;
 113     }
 114
 115   return {};
 116 }
 117
 118 #ifdef HAVE_SOURCE_HIGHLIGHT
 119
 120 /* Return the Source Highlight language name, given a gdb language
 121    LANG.  Returns NULL if the language is not known.  */
 122
 123 static const char *
 124 get_language_name (enum language lang)
 125 {
 126   switch (lang)
 127     {
 128     case language_c:
 129     case language_objc:
 130       return "c.lang";
 131
 132     case language_cplus:
 133       return "cpp.lang";
 134
 135     case language_d:
 136       return "d.lang";
 137
 138     case language_go:
 139       return "go.lang";
 140
 141     case language_fortran:
 142       return "fortran.lang";
 143
 144     case language_m2:
 145       /* Not handled by Source Highlight.  */
 146       break;
 147
 148     case language_asm:
 149       return "asm.lang";
 150
 151     case language_pascal:
 152       return "pascal.lang";
 153
 154     case language_opencl:
 155       /* Not handled by Source Highlight.  */
 156       break;
 157
 158     case language_rust:
 159       /* Not handled by Source Highlight.  */
 160       break;
 161
 162     case language_ada:
 163       return "ada.lang";
 164
 165     default:
 166       break;
 167     }
 168
 169   return nullptr;
 170 }
 171
 172 #endif /* HAVE_SOURCE_HIGHLIGHT */
 173
 174 /* See source-cache.h.  */
 175
 176 bool
 177 source_cache::get_source_lines (struct symtab *s, int first_line,
 178                                 int last_line, std::string *lines)
 179 {
 180   if (first_line < 1 || last_line < 1 || first_line > last_line)
 181     return false;
 182
 183 #ifdef HAVE_SOURCE_HIGHLIGHT
 184   if (source_styling && can_emit_style_escape (gdb_stdout))
 185     {
 186       const char *fullname = symtab_to_fullname (s);
 187
 188       for (const auto &item : m_source_map)
 189         {
 190           if (item.fullname == fullname)
 191             {
 192               *lines = extract_lines (item, first_line, last_line);
 193               return true;
 194             }
 195         }
 196
 197       const char *lang_name = get_language_name (SYMTAB_LANGUAGE (s));
 198       if (lang_name != nullptr)
 199         {
 200           std::ifstream input (fullname);
 201           if (input.is_open ())
 202             {
 203               if (s->line_charpos == 0)
 204                 {
 205                   scoped_fd desc = open_source_file (s);
 206                   if (desc.get () < 0)
 207                     return false;
 208                   find_source_lines (s, desc.get ());
 209
 210                   /* FULLNAME points to a value owned by the symtab
 211                      (symtab::fullname).  Calling open_source_file reallocates
 212                      that value, so we must refresh FULLNAME to avoid a
 213                      use-after-free.  */
 214                   fullname = symtab_to_fullname (s);
 215                 }
 216               srchilite::SourceHighlight highlighter ("esc.outlang");
 217               highlighter.setStyleFile("esc.style");
 218
 219               std::ostringstream output;
 220               highlighter.highlight (input, output, lang_name, fullname);
 221
 222               source_text result = { fullname, output.str () };
 223               m_source_map.push_back (std::move (result));
 224
 225               if (m_source_map.size () > MAX_ENTRIES)
 226                 m_source_map.erase (m_source_map.begin ());
 227
 228               *lines = extract_lines (m_source_map.back (), first_line,
 229                                       last_line);
 230               return true;
 231             }
 232         }
 233     }
 234 #endif /* HAVE_SOURCE_HIGHLIGHT */
 235
 236   return get_plain_source_lines (s, first_line, last_line, lines);
 237 }