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