| 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 "gdbsupport/scoped_fd.h" |
| 22 | #include "source.h" |
| 23 | #include "cli/cli-style.h" |
| 24 | #include "symtab.h" |
| 25 | #include "gdbsupport/selftest.h" |
| 26 | #include "objfiles.h" |
| 27 | #include "exec.h" |
| 28 | |
| 29 | #ifdef HAVE_SOURCE_HIGHLIGHT |
| 30 | /* If Gnulib redirects 'open' and 'close' to its replacements |
| 31 | 'rpl_open' and 'rpl_close' via cpp macros, including <fstream> |
| 32 | below with those macros in effect will cause unresolved externals |
| 33 | when GDB is linked. Happens, e.g., in the MinGW build. */ |
| 34 | #undef open |
| 35 | #undef close |
| 36 | #include <sstream> |
| 37 | #include <srchilite/sourcehighlight.h> |
| 38 | #include <srchilite/langmap.h> |
| 39 | #endif |
| 40 | |
| 41 | /* The number of source files we'll cache. */ |
| 42 | |
| 43 | #define MAX_ENTRIES 5 |
| 44 | |
| 45 | /* See source-cache.h. */ |
| 46 | |
| 47 | source_cache g_source_cache; |
| 48 | |
| 49 | /* See source-cache.h. */ |
| 50 | |
| 51 | std::string |
| 52 | source_cache::get_plain_source_lines (struct symtab *s, |
| 53 | const std::string &fullname) |
| 54 | { |
| 55 | scoped_fd desc (open_source_file (s)); |
| 56 | if (desc.get () < 0) |
| 57 | perror_with_name (symtab_to_filename_for_display (s)); |
| 58 | |
| 59 | struct stat st; |
| 60 | if (fstat (desc.get (), &st) < 0) |
| 61 | perror_with_name (symtab_to_filename_for_display (s)); |
| 62 | |
| 63 | std::string lines; |
| 64 | lines.resize (st.st_size); |
| 65 | if (myread (desc.get (), &lines[0], lines.size ()) < 0) |
| 66 | perror_with_name (symtab_to_filename_for_display (s)); |
| 67 | |
| 68 | time_t mtime = 0; |
| 69 | if (SYMTAB_OBJFILE (s) != NULL && SYMTAB_OBJFILE (s)->obfd != NULL) |
| 70 | mtime = SYMTAB_OBJFILE (s)->mtime; |
| 71 | else if (exec_bfd) |
| 72 | mtime = exec_bfd_mtime; |
| 73 | |
| 74 | if (mtime && mtime < st.st_mtime) |
| 75 | warning (_("Source file is more recent than executable.")); |
| 76 | |
| 77 | std::vector<off_t> offsets; |
| 78 | offsets.push_back (0); |
| 79 | for (size_t offset = lines.find ('\n'); |
| 80 | offset != std::string::npos; |
| 81 | offset = lines.find ('\n', offset)) |
| 82 | { |
| 83 | ++offset; |
| 84 | /* A newline at the end does not start a new line. It would |
| 85 | seem simpler to just strip the newline in this function, but |
| 86 | then "list" won't print the final newline. */ |
| 87 | if (offset != lines.size ()) |
| 88 | offsets.push_back (offset); |
| 89 | } |
| 90 | |
| 91 | offsets.shrink_to_fit (); |
| 92 | m_offset_cache.emplace (fullname, std::move (offsets)); |
| 93 | |
| 94 | return lines; |
| 95 | } |
| 96 | |
| 97 | #ifdef HAVE_SOURCE_HIGHLIGHT |
| 98 | |
| 99 | /* Return the Source Highlight language name, given a gdb language |
| 100 | LANG. Returns NULL if the language is not known. */ |
| 101 | |
| 102 | static const char * |
| 103 | get_language_name (enum language lang) |
| 104 | { |
| 105 | switch (lang) |
| 106 | { |
| 107 | case language_c: |
| 108 | case language_objc: |
| 109 | return "c.lang"; |
| 110 | |
| 111 | case language_cplus: |
| 112 | return "cpp.lang"; |
| 113 | |
| 114 | case language_d: |
| 115 | return "d.lang"; |
| 116 | |
| 117 | case language_go: |
| 118 | return "go.lang"; |
| 119 | |
| 120 | case language_fortran: |
| 121 | return "fortran.lang"; |
| 122 | |
| 123 | case language_m2: |
| 124 | /* Not handled by Source Highlight. */ |
| 125 | break; |
| 126 | |
| 127 | case language_asm: |
| 128 | return "asm.lang"; |
| 129 | |
| 130 | case language_pascal: |
| 131 | return "pascal.lang"; |
| 132 | |
| 133 | case language_opencl: |
| 134 | /* Not handled by Source Highlight. */ |
| 135 | break; |
| 136 | |
| 137 | case language_rust: |
| 138 | return "rust.lang"; |
| 139 | |
| 140 | case language_ada: |
| 141 | return "ada.lang"; |
| 142 | |
| 143 | default: |
| 144 | break; |
| 145 | } |
| 146 | |
| 147 | return nullptr; |
| 148 | } |
| 149 | |
| 150 | #endif /* HAVE_SOURCE_HIGHLIGHT */ |
| 151 | |
| 152 | /* See source-cache.h. */ |
| 153 | |
| 154 | bool |
| 155 | source_cache::ensure (struct symtab *s) |
| 156 | { |
| 157 | std::string fullname = symtab_to_fullname (s); |
| 158 | |
| 159 | size_t size = m_source_map.size (); |
| 160 | for (int i = 0; i < size; ++i) |
| 161 | { |
| 162 | if (m_source_map[i].fullname == fullname) |
| 163 | { |
| 164 | /* This should always hold, because we create the file |
| 165 | offsets when reading the file, and never free them |
| 166 | without also clearing the contents cache. */ |
| 167 | gdb_assert (m_offset_cache.find (fullname) |
| 168 | != m_offset_cache.end ()); |
| 169 | /* Not strictly LRU, but at least ensure that the most |
| 170 | recently used entry is always the last candidate for |
| 171 | deletion. Note that this property is relied upon by at |
| 172 | least one caller. */ |
| 173 | if (i != size - 1) |
| 174 | std::swap (m_source_map[i], m_source_map[size - 1]); |
| 175 | return true; |
| 176 | } |
| 177 | } |
| 178 | |
| 179 | std::string contents = get_plain_source_lines (s, fullname); |
| 180 | |
| 181 | #ifdef HAVE_SOURCE_HIGHLIGHT |
| 182 | if (source_styling && gdb_stdout->can_emit_style_escape ()) |
| 183 | { |
| 184 | const char *lang_name = get_language_name (SYMTAB_LANGUAGE (s)); |
| 185 | if (lang_name != nullptr) |
| 186 | { |
| 187 | /* The global source highlight object, or null if one was |
| 188 | never constructed. This is stored here rather than in |
| 189 | the class so that we don't need to include anything or do |
| 190 | conditional compilation in source-cache.h. */ |
| 191 | static srchilite::SourceHighlight *highlighter; |
| 192 | |
| 193 | try |
| 194 | { |
| 195 | if (highlighter == nullptr) |
| 196 | { |
| 197 | highlighter = new srchilite::SourceHighlight ("esc.outlang"); |
| 198 | highlighter->setStyleFile ("esc.style"); |
| 199 | } |
| 200 | |
| 201 | std::istringstream input (contents); |
| 202 | std::ostringstream output; |
| 203 | highlighter->highlight (input, output, lang_name, fullname); |
| 204 | contents = output.str (); |
| 205 | } |
| 206 | catch (...) |
| 207 | { |
| 208 | /* Source Highlight will throw an exception if |
| 209 | highlighting fails. One possible reason it can fail |
| 210 | is if the language is unknown -- which matters to gdb |
| 211 | because Rust support wasn't added until after 3.1.8. |
| 212 | Ignore exceptions here and fall back to |
| 213 | un-highlighted text. */ |
| 214 | } |
| 215 | } |
| 216 | } |
| 217 | #endif /* HAVE_SOURCE_HIGHLIGHT */ |
| 218 | |
| 219 | source_text result = { std::move (fullname), std::move (contents) }; |
| 220 | m_source_map.push_back (std::move (result)); |
| 221 | |
| 222 | if (m_source_map.size () > MAX_ENTRIES) |
| 223 | m_source_map.erase (m_source_map.begin ()); |
| 224 | |
| 225 | return true; |
| 226 | } |
| 227 | |
| 228 | /* See source-cache.h. */ |
| 229 | |
| 230 | bool |
| 231 | source_cache::get_line_charpos (struct symtab *s, |
| 232 | const std::vector<off_t> **offsets) |
| 233 | { |
| 234 | try |
| 235 | { |
| 236 | std::string fullname = symtab_to_fullname (s); |
| 237 | |
| 238 | auto iter = m_offset_cache.find (fullname); |
| 239 | if (iter == m_offset_cache.end ()) |
| 240 | { |
| 241 | ensure (s); |
| 242 | iter = m_offset_cache.find (fullname); |
| 243 | /* cache_source_text ensured this was entered. */ |
| 244 | gdb_assert (iter != m_offset_cache.end ()); |
| 245 | } |
| 246 | |
| 247 | *offsets = &iter->second; |
| 248 | return true; |
| 249 | } |
| 250 | catch (const gdb_exception_error &e) |
| 251 | { |
| 252 | return false; |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | /* A helper function that extracts the desired source lines from TEXT, |
| 257 | putting them into LINES_OUT. The arguments are as for |
| 258 | get_source_lines. Returns true on success, false if the line |
| 259 | numbers are invalid. */ |
| 260 | |
| 261 | static bool |
| 262 | extract_lines (const std::string &text, int first_line, int last_line, |
| 263 | std::string *lines_out) |
| 264 | { |
| 265 | int lineno = 1; |
| 266 | std::string::size_type pos = 0; |
| 267 | std::string::size_type first_pos = std::string::npos; |
| 268 | |
| 269 | while (pos != std::string::npos && lineno <= last_line) |
| 270 | { |
| 271 | std::string::size_type new_pos = text.find ('\n', pos); |
| 272 | |
| 273 | if (lineno == first_line) |
| 274 | first_pos = pos; |
| 275 | |
| 276 | pos = new_pos; |
| 277 | if (lineno == last_line || pos == std::string::npos) |
| 278 | { |
| 279 | /* A newline at the end does not start a new line. */ |
| 280 | if (first_pos == std::string::npos |
| 281 | || first_pos == text.size ()) |
| 282 | return false; |
| 283 | if (pos == std::string::npos) |
| 284 | pos = text.size (); |
| 285 | else |
| 286 | ++pos; |
| 287 | *lines_out = text.substr (first_pos, pos - first_pos); |
| 288 | return true; |
| 289 | } |
| 290 | ++lineno; |
| 291 | ++pos; |
| 292 | } |
| 293 | |
| 294 | return false; |
| 295 | } |
| 296 | |
| 297 | /* See source-cache.h. */ |
| 298 | |
| 299 | bool |
| 300 | source_cache::get_source_lines (struct symtab *s, int first_line, |
| 301 | int last_line, std::string *lines) |
| 302 | { |
| 303 | if (first_line < 1 || last_line < 1 || first_line > last_line) |
| 304 | return false; |
| 305 | |
| 306 | if (!ensure (s)) |
| 307 | return false; |
| 308 | |
| 309 | return extract_lines (m_source_map.back ().contents, |
| 310 | first_line, last_line, lines); |
| 311 | } |
| 312 | |
| 313 | #if GDB_SELF_TEST |
| 314 | namespace selftests |
| 315 | { |
| 316 | static void extract_lines_test () |
| 317 | { |
| 318 | std::string input_text = "abc\ndef\nghi\njkl\n"; |
| 319 | std::string result; |
| 320 | |
| 321 | SELF_CHECK (extract_lines (input_text, 1, 1, &result) |
| 322 | && result == "abc\n"); |
| 323 | SELF_CHECK (!extract_lines (input_text, 2, 1, &result)); |
| 324 | SELF_CHECK (extract_lines (input_text, 1, 2, &result) |
| 325 | && result == "abc\ndef\n"); |
| 326 | SELF_CHECK (extract_lines ("abc", 1, 1, &result) |
| 327 | && result == "abc"); |
| 328 | } |
| 329 | } |
| 330 | #endif |
| 331 | |
| 332 | void |
| 333 | _initialize_source_cache () |
| 334 | { |
| 335 | #if GDB_SELF_TEST |
| 336 | selftests::register_test ("source-cache", selftests::extract_lines_test); |
| 337 | #endif |
| 338 | } |