ws.c

   1 /*
   2  * Whitespace rules
   3  *
   4  * Copyright (c) 2007 Junio C Hamano
   5  */
   6
   7 #include "cache.h"
   8 #include "attr.h"
   9
  10 static struct whitespace_rule {
  11         const char *rule_name;
  12         unsigned rule_bits;
  13         unsigned loosens_error:1,
  14                 exclude_default:1;
  15 } whitespace_rule_names[] = {
  16         { "trailing-space", WS_TRAILING_SPACE, 0 },
  17         { "space-before-tab", WS_SPACE_BEFORE_TAB, 0 },
  18         { "indent-with-non-tab", WS_INDENT_WITH_NON_TAB, 0 },
  19         { "cr-at-eol", WS_CR_AT_EOL, 1 },
  20         { "blank-at-eol", WS_BLANK_AT_EOL, 0 },
  21         { "blank-at-eof", WS_BLANK_AT_EOF, 0 },
  22         { "tab-in-indent", WS_TAB_IN_INDENT, 0, 1 },
  23 };
  24
  25 unsigned parse_whitespace_rule(const char *string)
  26 {
  27         unsigned rule = WS_DEFAULT_RULE;
  28
  29         while (string) {
  30                 int i;
  31                 size_t len;
  32                 const char *ep;
  33                 int negated = 0;
  34
  35                 string = string + strspn(string, ", \t\n\r");
  36                 ep = strchr(string, ',');
  37                 if (!ep)
  38                         len = strlen(string);
  39                 else
  40                         len = ep - string;
  41
  42                 if (*string == '-') {
  43                         negated = 1;
  44                         string++;
  45                         len--;
  46                 }
  47                 if (!len)
  48                         break;
  49                 for (i = 0; i < ARRAY_SIZE(whitespace_rule_names); i++) {
  50                         if (strncmp(whitespace_rule_names[i].rule_name,
  51                                     string, len))
  52                                 continue;
  53                         if (negated)
  54                                 rule &= ~whitespace_rule_names[i].rule_bits;
  55                         else
  56                                 rule |= whitespace_rule_names[i].rule_bits;
  57                         break;
  58                 }
  59                 if (strncmp(string, "tabwidth=", 9) == 0) {
  60                         unsigned tabwidth = atoi(string + 9);
  61                         if (0 < tabwidth && tabwidth < 0100) {
  62                                 rule &= ~WS_TAB_WIDTH_MASK;
  63                                 rule |= tabwidth;
  64                         }
  65                         else
  66                                 warning("tabwidth %.*s out of range",
  67                                         (int)(len - 9), string + 9);
  68                 }
  69                 string = ep;
  70         }
  71
  72         if (rule & WS_TAB_IN_INDENT && rule & WS_INDENT_WITH_NON_TAB)
  73                 die("cannot enforce both tab-in-indent and indent-with-non-tab");
  74         return rule;
  75 }
  76
  77 static void setup_whitespace_attr_check(struct git_attr_check *check)
  78 {
  79         static struct git_attr *attr_whitespace;
  80
  81         if (!attr_whitespace)
  82                 attr_whitespace = git_attr("whitespace");
  83         check[0].attr = attr_whitespace;
  84 }
  85
  86 unsigned whitespace_rule(const char *pathname)
  87 {
  88         struct git_attr_check attr_whitespace_rule;
  89
  90         setup_whitespace_attr_check(&attr_whitespace_rule);
  91         if (!git_check_attr(pathname, 1, &attr_whitespace_rule)) {
  92                 const char *value;
  93
  94                 value = attr_whitespace_rule.value;
  95                 if (ATTR_TRUE(value)) {
  96                         /* true (whitespace) */
  97                         unsigned all_rule = ws_tab_width(whitespace_rule_cfg);
  98                         int i;
  99                         for (i = 0; i < ARRAY_SIZE(whitespace_rule_names); i++)
 100                                 if (!whitespace_rule_names[i].loosens_error &&
 101                                     !whitespace_rule_names[i].exclude_default)
 102                                         all_rule |= whitespace_rule_names[i].rule_bits;
 103                         return all_rule;
 104                 } else if (ATTR_FALSE(value)) {
 105                         /* false (-whitespace) */
 106                         return ws_tab_width(whitespace_rule_cfg);
 107                 } else if (ATTR_UNSET(value)) {
 108                         /* reset to default (!whitespace) */
 109                         return whitespace_rule_cfg;
 110                 } else {
 111                         /* string */
 112                         return parse_whitespace_rule(value);
 113                 }
 114         } else {
 115                 return whitespace_rule_cfg;
 116         }
 117 }
 118
 119 /* The returned string should be freed by the caller. */
 120 char *whitespace_error_string(unsigned ws)
 121 {
 122         struct strbuf err = STRBUF_INIT;
 123         if ((ws & WS_TRAILING_SPACE) == WS_TRAILING_SPACE)
 124                 strbuf_addstr(&err, "trailing whitespace");
 125         else {
 126                 if (ws & WS_BLANK_AT_EOL)
 127                         strbuf_addstr(&err, "trailing whitespace");
 128                 if (ws & WS_BLANK_AT_EOF) {
 129                         if (err.len)
 130                                 strbuf_addstr(&err, ", ");
 131                         strbuf_addstr(&err, "new blank line at EOF");
 132                 }
 133         }
 134         if (ws & WS_SPACE_BEFORE_TAB) {
 135                 if (err.len)
 136                         strbuf_addstr(&err, ", ");
 137                 strbuf_addstr(&err, "space before tab in indent");
 138         }
 139         if (ws & WS_INDENT_WITH_NON_TAB) {
 140                 if (err.len)
 141                         strbuf_addstr(&err, ", ");
 142                 strbuf_addstr(&err, "indent with spaces");
 143         }
 144         if (ws & WS_TAB_IN_INDENT) {
 145                 if (err.len)
 146                         strbuf_addstr(&err, ", ");
 147                 strbuf_addstr(&err, "tab in indent");
 148         }
 149         return strbuf_detach(&err, NULL);
 150 }
 151
 152 /* If stream is non-NULL, emits the line after checking. */
 153 static unsigned ws_check_emit_1(const char *line, int len, unsigned ws_rule,
 154                                 FILE *stream, const char *set,
 155                                 const char *reset, const char *ws)
 156 {
 157         unsigned result = 0;
 158         int written = 0;
 159         int trailing_whitespace = -1;
 160         int trailing_newline = 0;
 161         int trailing_carriage_return = 0;
 162         int i;
 163
 164         /* Logic is simpler if we temporarily ignore the trailing newline. */
 165         if (len > 0 && line[len - 1] == '\n') {
 166                 trailing_newline = 1;
 167                 len--;
 168         }
 169         if ((ws_rule & WS_CR_AT_EOL) &&
 170             len > 0 && line[len - 1] == '\r') {
 171                 trailing_carriage_return = 1;
 172                 len--;
 173         }
 174
 175         /* Check for trailing whitespace. */
 176         if (ws_rule & WS_BLANK_AT_EOL) {
 177                 for (i = len - 1; i >= 0; i--) {
 178                         if (isspace(line[i])) {
 179                                 trailing_whitespace = i;
 180                                 result |= WS_BLANK_AT_EOL;
 181                         }
 182                         else
 183                                 break;
 184                 }
 185         }
 186
 187         if (trailing_whitespace == -1)
 188                 trailing_whitespace = len;
 189
 190         /* Check indentation */
 191         for (i = 0; i < trailing_whitespace; i++) {
 192                 if (line[i] == ' ')
 193                         continue;
 194                 if (line[i] != '\t')
 195                         break;
 196                 if ((ws_rule & WS_SPACE_BEFORE_TAB) && written < i) {
 197                         result |= WS_SPACE_BEFORE_TAB;
 198                         if (stream) {
 199                                 fputs(ws, stream);
 200                                 fwrite(line + written, i - written, 1, stream);
 201                                 fputs(reset, stream);
 202                                 fwrite(line + i, 1, 1, stream);
 203                         }
 204                 } else if (ws_rule & WS_TAB_IN_INDENT) {
 205                         result |= WS_TAB_IN_INDENT;
 206                         if (stream) {
 207                                 fwrite(line + written, i - written, 1, stream);
 208                                 fputs(ws, stream);
 209                                 fwrite(line + i, 1, 1, stream);
 210                                 fputs(reset, stream);
 211                         }
 212                 } else if (stream) {
 213                         fwrite(line + written, i - written + 1, 1, stream);
 214                 }
 215                 written = i + 1;
 216         }
 217
 218         /* Check for indent using non-tab. */
 219         if ((ws_rule & WS_INDENT_WITH_NON_TAB) && i - written >= ws_tab_width(ws_rule)) {
 220                 result |= WS_INDENT_WITH_NON_TAB;
 221                 if (stream) {
 222                         fputs(ws, stream);
 223                         fwrite(line + written, i - written, 1, stream);
 224                         fputs(reset, stream);
 225                 }
 226                 written = i;
 227         }
 228
 229         if (stream) {
 230                 /*
 231                  * Now the rest of the line starts at "written".
 232                  * The non-highlighted part ends at "trailing_whitespace".
 233                  */
 234
 235                 /* Emit non-highlighted (middle) segment. */
 236                 if (trailing_whitespace - written > 0) {
 237                         fputs(set, stream);
 238                         fwrite(line + written,
 239                             trailing_whitespace - written, 1, stream);
 240                         fputs(reset, stream);
 241                 }
 242
 243                 /* Highlight errors in trailing whitespace. */
 244                 if (trailing_whitespace != len) {
 245                         fputs(ws, stream);
 246                         fwrite(line + trailing_whitespace,
 247                             len - trailing_whitespace, 1, stream);
 248                         fputs(reset, stream);
 249                 }
 250                 if (trailing_carriage_return)
 251                         fputc('\r', stream);
 252                 if (trailing_newline)
 253                         fputc('\n', stream);
 254         }
 255         return result;
 256 }
 257
 258 void ws_check_emit(const char *line, int len, unsigned ws_rule,
 259                    FILE *stream, const char *set,
 260                    const char *reset, const char *ws)
 261 {
 262         (void)ws_check_emit_1(line, len, ws_rule, stream, set, reset, ws);
 263 }
 264
 265 unsigned ws_check(const char *line, int len, unsigned ws_rule)
 266 {
 267         return ws_check_emit_1(line, len, ws_rule, NULL, NULL, NULL, NULL);
 268 }
 269
 270 int ws_blank_line(const char *line, int len, unsigned ws_rule)
 271 {
 272         /*
 273          * We _might_ want to treat CR differently from other
 274          * whitespace characters when ws_rule has WS_CR_AT_EOL, but
 275          * for now we just use this stupid definition.
 276          */
 277         while (len-- > 0) {
 278                 if (!isspace(*line))
 279                         return 0;
 280                 line++;
 281         }
 282         return 1;
 283 }
 284
 285 /* Copy the line onto the end of the strbuf while fixing whitespaces */
 286 void ws_fix_copy(struct strbuf *dst, const char *src, int len, unsigned ws_rule, int *error_count)
 287 {
 288         /*
 289          * len is number of bytes to be copied from src, starting
 290          * at src.  Typically src[len-1] is '\n', unless this is
 291          * the incomplete last line.
 292          */
 293         int i;
 294         int add_nl_to_tail = 0;
 295         int add_cr_to_tail = 0;
 296         int fixed = 0;
 297         int last_tab_in_indent = -1;
 298         int last_space_in_indent = -1;
 299         int need_fix_leading_space = 0;
 300
 301         /*
 302          * Strip trailing whitespace
 303          */
 304         if (ws_rule & WS_BLANK_AT_EOL) {
 305                 if (0 < len && src[len - 1] == '\n') {
 306                         add_nl_to_tail = 1;
 307                         len--;
 308                         if (0 < len && src[len - 1] == '\r') {
 309                                 add_cr_to_tail = !!(ws_rule & WS_CR_AT_EOL);
 310                                 len--;
 311                         }
 312                 }
 313                 if (0 < len && isspace(src[len - 1])) {
 314                         while (0 < len && isspace(src[len-1]))
 315                                 len--;
 316                         fixed = 1;
 317                 }
 318         }
 319
 320         /*
 321          * Check leading whitespaces (indent)
 322          */
 323         for (i = 0; i < len; i++) {
 324                 char ch = src[i];
 325                 if (ch == '\t') {
 326                         last_tab_in_indent = i;
 327                         if ((ws_rule & WS_SPACE_BEFORE_TAB) &&
 328                             0 <= last_space_in_indent)
 329                             need_fix_leading_space = 1;
 330                 } else if (ch == ' ') {
 331                         last_space_in_indent = i;
 332                         if ((ws_rule & WS_INDENT_WITH_NON_TAB) &&
 333                             ws_tab_width(ws_rule) <= i - last_tab_in_indent)
 334                                 need_fix_leading_space = 1;
 335                 } else
 336                         break;
 337         }
 338
 339         if (need_fix_leading_space) {
 340                 /* Process indent ourselves */
 341                 int consecutive_spaces = 0;
 342                 int last = last_tab_in_indent + 1;
 343
 344                 if (ws_rule & WS_INDENT_WITH_NON_TAB) {
 345                         /* have "last" point at one past the indent */
 346                         if (last_tab_in_indent < last_space_in_indent)
 347                                 last = last_space_in_indent + 1;
 348                         else
 349                                 last = last_tab_in_indent + 1;
 350                 }
 351
 352                 /*
 353                  * between src[0..last-1], strip the funny spaces,
 354                  * updating them to tab as needed.
 355                  */
 356                 for (i = 0; i < last; i++) {
 357                         char ch = src[i];
 358                         if (ch != ' ') {
 359                                 consecutive_spaces = 0;
 360                                 strbuf_addch(dst, ch);
 361                         } else {
 362                                 consecutive_spaces++;
 363                                 if (consecutive_spaces == ws_tab_width(ws_rule)) {
 364                                         strbuf_addch(dst, '\t');
 365                                         consecutive_spaces = 0;
 366                                 }
 367                         }
 368                 }
 369                 while (0 < consecutive_spaces--)
 370                         strbuf_addch(dst, ' ');
 371                 len -= last;
 372                 src += last;
 373                 fixed = 1;
 374         } else if ((ws_rule & WS_TAB_IN_INDENT) && last_tab_in_indent >= 0) {
 375                 /* Expand tabs into spaces */
 376                 int start = dst->len;
 377                 int last = last_tab_in_indent + 1;
 378                 for (i = 0; i < last; i++) {
 379                         if (src[i] == '\t')
 380                                 do {
 381                                         strbuf_addch(dst, ' ');
 382                                 } while ((dst->len - start) % ws_tab_width(ws_rule));
 383                         else
 384                                 strbuf_addch(dst, src[i]);
 385                 }
 386                 len -= last;
 387                 src += last;
 388                 fixed = 1;
 389         }
 390
 391         strbuf_add(dst, src, len);
 392         if (add_cr_to_tail)
 393                 strbuf_addch(dst, '\r');
 394         if (add_nl_to_tail)
 395                 strbuf_addch(dst, '\n');
 396         if (fixed && error_count)
 397                 (*error_count)++;
 398 }