ui-ssdiff.c

   1 #include "cgit.h"
   2 #include "html.h"
   3 #include "ui-shared.h"
   4 #include "ui-diff.h"
   5 #include "ui-ssdiff.h"
   6
   7 extern int use_ssdiff;
   8
   9 static int current_old_line, current_new_line;
  10 static int **L = NULL;
  11
  12 struct deferred_lines {
  13         int line_no;
  14         char *line;
  15         struct deferred_lines *next;
  16 };
  17
  18 static struct deferred_lines *deferred_old, *deferred_old_last;
  19 static struct deferred_lines *deferred_new, *deferred_new_last;
  20
  21 static void create_or_reset_lcs_table()
  22 {
  23         int i;
  24
  25         if (L != NULL) {
  26                 memset(*L, 0, sizeof(int) * MAX_SSDIFF_SIZE);
  27                 return;
  28         }
  29
  30         // xcalloc will die if we ran out of memory;
  31         // not very helpful for debugging
  32         L = (int**)xcalloc(MAX_SSDIFF_M, sizeof(int *));
  33         *L = (int*)xcalloc(MAX_SSDIFF_SIZE, sizeof(int));
  34
  35         for (i = 1; i < MAX_SSDIFF_M; i++) {
  36                 L[i] = *L + i * MAX_SSDIFF_N;
  37         }
  38 }
  39
  40 static char *longest_common_subsequence(char *A, char *B)
  41 {
  42         int i, j, ri;
  43         int m = strlen(A);
  44         int n = strlen(B);
  45         int tmp1, tmp2;
  46         int lcs_length;
  47         char *result;
  48
  49         // We bail if the lines are too long
  50         if (m >= MAX_SSDIFF_M || n >= MAX_SSDIFF_N)
  51                 return NULL;
  52
  53         create_or_reset_lcs_table();
  54
  55         for (i = m; i >= 0; i--) {
  56                 for (j = n; j >= 0; j--) {
  57                         if (A[i] == '\0' || B[j] == '\0') {
  58                                 L[i][j] = 0;
  59                         } else if (A[i] == B[j]) {
  60                                 L[i][j] = 1 + L[i + 1][j + 1];
  61                         } else {
  62                                 tmp1 = L[i + 1][j];
  63                                 tmp2 = L[i][j + 1];
  64                                 L[i][j] = (tmp1 > tmp2 ? tmp1 : tmp2);
  65                         }
  66                 }
  67         }
  68
  69         lcs_length = L[0][0];
  70         result = xmalloc(lcs_length + 2);
  71         memset(result, 0, sizeof(*result) * (lcs_length + 2));
  72
  73         ri = 0;
  74         i = 0;
  75         j = 0;
  76         while (i < m && j < n) {
  77                 if (A[i] == B[j]) {
  78                         result[ri] = A[i];
  79                         ri += 1;
  80                         i += 1;
  81                         j += 1;
  82                 } else if (L[i + 1][j] >= L[i][j + 1]) {
  83                         i += 1;
  84                 } else {
  85                         j += 1;
  86                 }
  87         }
  88
  89         return result;
  90 }
  91
  92 static int line_from_hunk(char *line, char type)
  93 {
  94         char *buf1, *buf2;
  95         int len;
  96
  97         buf1 = strchr(line, type);
  98         if (buf1 == NULL)
  99                 return 0;
 100         buf1 += 1;
 101         buf2 = strchr(buf1, ',');
 102         if (buf2 == NULL)
 103                 return 0;
 104         len = buf2 - buf1;
 105         buf2 = xmalloc(len + 1);
 106         strncpy(buf2, buf1, len);
 107         buf2[len] = '\0';
 108         int res = atoi(buf2);
 109         free(buf2);
 110         return res;
 111 }
 112
 113 static char *replace_tabs(char *line)
 114 {
 115         char *prev_buf = line;
 116         char *cur_buf;
 117         int linelen = strlen(line);
 118         int n_tabs = 0;
 119         int i;
 120         char *result;
 121         char *spaces = "        ";
 122
 123         if (linelen == 0) {
 124                 result = xmalloc(1);
 125                 result[0] = '\0';
 126                 return result;
 127         }
 128
 129         for (i = 0; i < linelen; i++)
 130                 if (line[i] == '\t')
 131                         n_tabs += 1;
 132         result = xmalloc(linelen + n_tabs * 8 + 1);
 133         result[0] = '\0';
 134
 135         while (1) {
 136                 cur_buf = strchr(prev_buf, '\t');
 137                 if (!cur_buf) {
 138                         strcat(result, prev_buf);
 139                         break;
 140                 } else {
 141                         strcat(result, " ");
 142                         strncat(result, spaces, 8 - (strlen(result) % 8));
 143                         strncat(result, prev_buf, cur_buf - prev_buf);
 144                 }
 145                 prev_buf = cur_buf + 1;
 146         }
 147         return result;
 148 }
 149
 150 static int calc_deferred_lines(struct deferred_lines *start)
 151 {
 152         struct deferred_lines *item = start;
 153         int result = 0;
 154         while (item) {
 155                 result += 1;
 156                 item = item->next;
 157         }
 158         return result;
 159 }
 160
 161 static void deferred_old_add(char *line, int line_no)
 162 {
 163         struct deferred_lines *item = xmalloc(sizeof(struct deferred_lines));
 164         item->line = xstrdup(line);
 165         item->line_no = line_no;
 166         item->next = NULL;
 167         if (deferred_old) {
 168                 deferred_old_last->next = item;
 169                 deferred_old_last = item;
 170         } else {
 171                 deferred_old = deferred_old_last = item;
 172         }
 173 }
 174
 175 static void deferred_new_add(char *line, int line_no)
 176 {
 177         struct deferred_lines *item = xmalloc(sizeof(struct deferred_lines));
 178         item->line = xstrdup(line);
 179         item->line_no = line_no;
 180         item->next = NULL;
 181         if (deferred_new) {
 182                 deferred_new_last->next = item;
 183                 deferred_new_last = item;
 184         } else {
 185                 deferred_new = deferred_new_last = item;
 186         }
 187 }
 188
 189 static void print_part_with_lcs(char *class, char *line, char *lcs)
 190 {
 191         int line_len = strlen(line);
 192         int i, j;
 193         char c[2] = " ";
 194         int same = 1;
 195
 196         j = 0;
 197         for (i = 0; i < line_len; i++) {
 198                 c[0] = line[i];
 199                 if (same) {
 200                         if (line[i] == lcs[j])
 201                                 j += 1;
 202                         else {
 203                                 same = 0;
 204                                 htmlf("<span class='%s'>", class);
 205                         }
 206                 } else if (line[i] == lcs[j]) {
 207                         same = 1;
 208                         htmlf("</span>");
 209                         j += 1;
 210                 }
 211                 html_txt(c);
 212         }
 213 }
 214
 215 static void print_ssdiff_line(char *class,
 216                               int old_line_no,
 217                               char *old_line,
 218                               int new_line_no,
 219                               char *new_line, int individual_chars)
 220 {
 221         char *lcs = NULL;
 222
 223         if (old_line)
 224                 old_line = replace_tabs(old_line + 1);
 225         if (new_line)
 226                 new_line = replace_tabs(new_line + 1);
 227         if (individual_chars && old_line && new_line)
 228                 lcs = longest_common_subsequence(old_line, new_line);
 229         html("<tr>\n");
 230         if (old_line_no > 0) {
 231                 struct diff_filespec *old_file = cgit_get_current_old_file();
 232                 char *lineno_str = fmt("n%d", old_line_no);
 233                 char *id_str = fmt("%s#%s", is_null_sha1(old_file->sha1)?"HEAD":sha1_to_hex(old_rev_sha1), lineno_str);
 234                 html("<td class='lineno'><a class='no' href='");
 235                 html(cgit_fileurl(ctx.repo->url, "tree", old_file->path, id_str));
 236                 htmlf("' id='%s' name='%s'>%s</a>", lineno_str, lineno_str, lineno_str + 1);
 237                 html("</td>");
 238                 htmlf("<td class='%s'>", class);
 239         } else if (old_line)
 240                 htmlf("<td class='lineno'></td><td class='%s'>", class);
 241         else
 242                 htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
 243         if (old_line) {
 244                 if (lcs)
 245                         print_part_with_lcs("del", old_line, lcs);
 246                 else
 247                         html_txt(old_line);
 248         }
 249
 250         html("</td>\n");
 251         if (new_line_no > 0) {
 252                 struct diff_filespec *new_file = cgit_get_current_new_file();
 253                 char *lineno_str = fmt("n%d", new_line_no);
 254                 char *id_str = fmt("%s#%s", is_null_sha1(new_file->sha1)?"HEAD":sha1_to_hex(new_rev_sha1), lineno_str);
 255                 html("<td class='lineno'><a class='no' href='");
 256                 html(cgit_fileurl(ctx.repo->url, "tree", new_file->path, id_str));
 257                 htmlf("' id='%s' name='%s'>%s</a>", lineno_str, lineno_str, lineno_str + 1);
 258                 html("</td>");
 259                 htmlf("<td class='%s'>", class);
 260         } else if (new_line)
 261                 htmlf("<td class='lineno'></td><td class='%s'>", class);
 262         else
 263                 htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
 264         if (new_line) {
 265                 if (lcs)
 266                         print_part_with_lcs("add", new_line, lcs);
 267                 else
 268                         html_txt(new_line);
 269         }
 270
 271         html("</td></tr>");
 272         if (lcs)
 273                 free(lcs);
 274         if (new_line)
 275                 free(new_line);
 276         if (old_line)
 277                 free(old_line);
 278 }
 279
 280 static void print_deferred_old_lines()
 281 {
 282         struct deferred_lines *iter_old, *tmp;
 283         iter_old = deferred_old;
 284         while (iter_old) {
 285                 print_ssdiff_line("del", iter_old->line_no,
 286                                   iter_old->line, -1, NULL, 0);
 287                 tmp = iter_old->next;
 288                 free(iter_old);
 289                 iter_old = tmp;
 290         }
 291 }
 292
 293 static void print_deferred_new_lines()
 294 {
 295         struct deferred_lines *iter_new, *tmp;
 296         iter_new = deferred_new;
 297         while (iter_new) {
 298                 print_ssdiff_line("add", -1, NULL,
 299                                   iter_new->line_no, iter_new->line, 0);
 300                 tmp = iter_new->next;
 301                 free(iter_new);
 302                 iter_new = tmp;
 303         }
 304 }
 305
 306 static void print_deferred_changed_lines()
 307 {
 308         struct deferred_lines *iter_old, *iter_new, *tmp;
 309         int n_old_lines = calc_deferred_lines(deferred_old);
 310         int n_new_lines = calc_deferred_lines(deferred_new);
 311         int individual_chars = (n_old_lines == n_new_lines ? 1 : 0);
 312
 313         iter_old = deferred_old;
 314         iter_new = deferred_new;
 315         while (iter_old || iter_new) {
 316                 if (iter_old && iter_new)
 317                         print_ssdiff_line("changed", iter_old->line_no,
 318                                           iter_old->line,
 319                                           iter_new->line_no, iter_new->line,
 320                                           individual_chars);
 321                 else if (iter_old)
 322                         print_ssdiff_line("changed", iter_old->line_no,
 323                                           iter_old->line, -1, NULL, 0);
 324                 else if (iter_new)
 325                         print_ssdiff_line("changed", -1, NULL,
 326                                           iter_new->line_no, iter_new->line, 0);
 327                 if (iter_old) {
 328                         tmp = iter_old->next;
 329                         free(iter_old);
 330                         iter_old = tmp;
 331                 }
 332
 333                 if (iter_new) {
 334                         tmp = iter_new->next;
 335                         free(iter_new);
 336                         iter_new = tmp;
 337                 }
 338         }
 339 }
 340
 341 void cgit_ssdiff_print_deferred_lines()
 342 {
 343         if (!deferred_old && !deferred_new)
 344                 return;
 345         if (deferred_old && !deferred_new)
 346                 print_deferred_old_lines();
 347         else if (!deferred_old && deferred_new)
 348                 print_deferred_new_lines();
 349         else
 350                 print_deferred_changed_lines();
 351         deferred_old = deferred_old_last = NULL;
 352         deferred_new = deferred_new_last = NULL;
 353 }
 354
 355 /*
 356  * print a single line returned from xdiff
 357  */
 358 void cgit_ssdiff_line_cb(char *line, int len)
 359 {
 360         char c = line[len - 1];
 361         line[len - 1] = '\0';
 362         if (line[0] == '@') {
 363                 current_old_line = line_from_hunk(line, '-');
 364                 current_new_line = line_from_hunk(line, '+');
 365         }
 366
 367         if (line[0] == ' ') {
 368                 if (deferred_old || deferred_new)
 369                         cgit_ssdiff_print_deferred_lines();
 370                 print_ssdiff_line("ctx", current_old_line, line,
 371                                   current_new_line, line, 0);
 372                 current_old_line += 1;
 373                 current_new_line += 1;
 374         } else if (line[0] == '+') {
 375                 deferred_new_add(line, current_new_line);
 376                 current_new_line += 1;
 377         } else if (line[0] == '-') {
 378                 deferred_old_add(line, current_old_line);
 379                 current_old_line += 1;
 380         } else if (line[0] == '@') {
 381                 html("<tr><td colspan='4' class='hunk'>");
 382                 html_txt(line);
 383                 html("</td></tr>");
 384         } else {
 385                 html("<tr><td colspan='4' class='ctx'>");
 386                 html_txt(line);
 387                 html("</td></tr>");
 388         }
 389         line[len - 1] = c;
 390 }
 391
 392 void cgit_ssdiff_header_begin()
 393 {
 394         current_old_line = -1;
 395         current_new_line = -1;
 396         html("<tr><td class='space' colspan='4'><div></div></td></tr>");
 397         html("<tr><td class='head' colspan='4'>");
 398 }
 399
 400 void cgit_ssdiff_header_end()
 401 {
 402         html("</td><tr>");
 403 }
 404
 405 void cgit_ssdiff_footer()
 406 {
 407         if (deferred_old || deferred_new)
 408                 cgit_ssdiff_print_deferred_lines();
 409         html("<tr><td class='foot' colspan='4'></td></tr>");
 410 }