ui-ssdiff.c

   1 #include "cgit.h"
   2 #include "ui-ssdiff.h"
   3 #include "html.h"
   4 #include "ui-shared.h"
   5 #include "ui-diff.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(void)
  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, res;
  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         strlcpy(buf2, buf1, len + 1);
 107         res = atoi(buf2);
 108         free(buf2);
 109         return res;
 110 }
 111
 112 static char *replace_tabs(char *line)
 113 {
 114         char *prev_buf = line;
 115         char *cur_buf;
 116         size_t linelen = strlen(line);
 117         int n_tabs = 0;
 118         int i;
 119         char *result;
 120         int result_len;
 121
 122         if (linelen == 0) {
 123                 result = xmalloc(1);
 124                 result[0] = '\0';
 125                 return result;
 126         }
 127
 128         for (i = 0; i < linelen; i++) {
 129                 if (line[i] == '\t')
 130                         n_tabs += 1;
 131         }
 132         result_len = linelen + n_tabs * 8;
 133         result = xmalloc(result_len + 1);
 134         result[0] = '\0';
 135
 136         for (;;) {
 137                 cur_buf = strchr(prev_buf, '\t');
 138                 if (!cur_buf) {
 139                         strncat(result, prev_buf, result_len);
 140                         break;
 141                 } else {
 142                         strncat(result, prev_buf, cur_buf - prev_buf);
 143                         linelen = strlen(result);
 144                         memset(&result[linelen], ' ', 8 - (linelen % 8));
 145                         result[linelen + 8 - (linelen % 8)] = '\0';
 146                 }
 147                 prev_buf = cur_buf + 1;
 148         }
 149         return result;
 150 }
 151
 152 static int calc_deferred_lines(struct deferred_lines *start)
 153 {
 154         struct deferred_lines *item = start;
 155         int result = 0;
 156         while (item) {
 157                 result += 1;
 158                 item = item->next;
 159         }
 160         return result;
 161 }
 162
 163 static void deferred_old_add(char *line, int line_no)
 164 {
 165         struct deferred_lines *item = xmalloc(sizeof(struct deferred_lines));
 166         item->line = xstrdup(line);
 167         item->line_no = line_no;
 168         item->next = NULL;
 169         if (deferred_old) {
 170                 deferred_old_last->next = item;
 171                 deferred_old_last = item;
 172         } else {
 173                 deferred_old = deferred_old_last = item;
 174         }
 175 }
 176
 177 static void deferred_new_add(char *line, int line_no)
 178 {
 179         struct deferred_lines *item = xmalloc(sizeof(struct deferred_lines));
 180         item->line = xstrdup(line);
 181         item->line_no = line_no;
 182         item->next = NULL;
 183         if (deferred_new) {
 184                 deferred_new_last->next = item;
 185                 deferred_new_last = item;
 186         } else {
 187                 deferred_new = deferred_new_last = item;
 188         }
 189 }
 190
 191 static void print_part_with_lcs(char *class, char *line, char *lcs)
 192 {
 193         int line_len = strlen(line);
 194         int i, j;
 195         char c[2] = " ";
 196         int same = 1;
 197
 198         j = 0;
 199         for (i = 0; i < line_len; i++) {
 200                 c[0] = line[i];
 201                 if (same) {
 202                         if (line[i] == lcs[j])
 203                                 j += 1;
 204                         else {
 205                                 same = 0;
 206                                 htmlf("<span class='%s'>", class);
 207                         }
 208                 } else if (line[i] == lcs[j]) {
 209                         same = 1;
 210                         htmlf("</span>");
 211                         j += 1;
 212                 }
 213                 html_txt(c);
 214         }
 215 }
 216
 217 static void print_ssdiff_line(char *class,
 218                               int old_line_no,
 219                               char *old_line,
 220                               int new_line_no,
 221                               char *new_line, int individual_chars)
 222 {
 223         char *lcs = NULL;
 224
 225         if (old_line)
 226                 old_line = replace_tabs(old_line + 1);
 227         if (new_line)
 228                 new_line = replace_tabs(new_line + 1);
 229         if (individual_chars && old_line && new_line)
 230                 lcs = longest_common_subsequence(old_line, new_line);
 231         html("<tr>\n");
 232         if (old_line_no > 0) {
 233                 struct diff_filespec *old_file = cgit_get_current_old_file();
 234                 char *lineno_str = fmt("n%d", old_line_no);
 235                 char *id_str = fmt("id=%s#%s", is_null_oid(&old_file->oid)?"HEAD":oid_to_hex(old_rev_oid), lineno_str);
 236                 char *fileurl = cgit_fileurl(ctx.repo->url, "tree", old_file->path, id_str);
 237                 html("<td class='lineno'><a href='");
 238                 html(fileurl);
 239                 htmlf("' id='%s'>%s</a>", lineno_str, lineno_str + 1);
 240                 html("</td>");
 241                 htmlf("<td class='%s'>", class);
 242                 free(fileurl);
 243         } else if (old_line)
 244                 htmlf("<td class='lineno'></td><td class='%s'>", class);
 245         else
 246                 htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
 247         if (old_line) {
 248                 if (lcs)
 249                         print_part_with_lcs("del", old_line, lcs);
 250                 else
 251                         html_txt(old_line);
 252         }
 253
 254         html("</td>\n");
 255         if (new_line_no > 0) {
 256                 struct diff_filespec *new_file = cgit_get_current_new_file();
 257                 char *lineno_str = fmt("n%d", new_line_no);
 258                 char *id_str = fmt("id=%s#%s", is_null_oid(&new_file->oid)?"HEAD":oid_to_hex(new_rev_oid), lineno_str);
 259                 char *fileurl = cgit_fileurl(ctx.repo->url, "tree", new_file->path, id_str);
 260                 html("<td class='lineno'><a href='");
 261                 html(fileurl);
 262                 htmlf("' id='%s'>%s</a>", lineno_str, lineno_str + 1);
 263                 html("</td>");
 264                 htmlf("<td class='%s'>", class);
 265                 free(fileurl);
 266         } else if (new_line)
 267                 htmlf("<td class='lineno'></td><td class='%s'>", class);
 268         else
 269                 htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
 270         if (new_line) {
 271                 if (lcs)
 272                         print_part_with_lcs("add", new_line, lcs);
 273                 else
 274                         html_txt(new_line);
 275         }
 276
 277         html("</td></tr>");
 278         if (lcs)
 279                 free(lcs);
 280         if (new_line)
 281                 free(new_line);
 282         if (old_line)
 283                 free(old_line);
 284 }
 285
 286 static void print_deferred_old_lines(void)
 287 {
 288         struct deferred_lines *iter_old, *tmp;
 289         iter_old = deferred_old;
 290         while (iter_old) {
 291                 print_ssdiff_line("del", iter_old->line_no,
 292                                   iter_old->line, -1, NULL, 0);
 293                 tmp = iter_old->next;
 294                 free(iter_old);
 295                 iter_old = tmp;
 296         }
 297 }
 298
 299 static void print_deferred_new_lines(void)
 300 {
 301         struct deferred_lines *iter_new, *tmp;
 302         iter_new = deferred_new;
 303         while (iter_new) {
 304                 print_ssdiff_line("add", -1, NULL,
 305                                   iter_new->line_no, iter_new->line, 0);
 306                 tmp = iter_new->next;
 307                 free(iter_new);
 308                 iter_new = tmp;
 309         }
 310 }
 311
 312 static void print_deferred_changed_lines(void)
 313 {
 314         struct deferred_lines *iter_old, *iter_new, *tmp;
 315         int n_old_lines = calc_deferred_lines(deferred_old);
 316         int n_new_lines = calc_deferred_lines(deferred_new);
 317         int individual_chars = (n_old_lines == n_new_lines ? 1 : 0);
 318
 319         iter_old = deferred_old;
 320         iter_new = deferred_new;
 321         while (iter_old || iter_new) {
 322                 if (iter_old && iter_new)
 323                         print_ssdiff_line("changed", iter_old->line_no,
 324                                           iter_old->line,
 325                                           iter_new->line_no, iter_new->line,
 326                                           individual_chars);
 327                 else if (iter_old)
 328                         print_ssdiff_line("changed", iter_old->line_no,
 329                                           iter_old->line, -1, NULL, 0);
 330                 else if (iter_new)
 331                         print_ssdiff_line("changed", -1, NULL,
 332                                           iter_new->line_no, iter_new->line, 0);
 333                 if (iter_old) {
 334                         tmp = iter_old->next;
 335                         free(iter_old);
 336                         iter_old = tmp;
 337                 }
 338
 339                 if (iter_new) {
 340                         tmp = iter_new->next;
 341                         free(iter_new);
 342                         iter_new = tmp;
 343                 }
 344         }
 345 }
 346
 347 void cgit_ssdiff_print_deferred_lines(void)
 348 {
 349         if (!deferred_old && !deferred_new)
 350                 return;
 351         if (deferred_old && !deferred_new)
 352                 print_deferred_old_lines();
 353         else if (!deferred_old && deferred_new)
 354                 print_deferred_new_lines();
 355         else
 356                 print_deferred_changed_lines();
 357         deferred_old = deferred_old_last = NULL;
 358         deferred_new = deferred_new_last = NULL;
 359 }
 360
 361 /*
 362  * print a single line returned from xdiff
 363  */
 364 void cgit_ssdiff_line_cb(char *line, int len)
 365 {
 366         char c = line[len - 1];
 367         line[len - 1] = '\0';
 368         if (line[0] == '@') {
 369                 current_old_line = line_from_hunk(line, '-');
 370                 current_new_line = line_from_hunk(line, '+');
 371         }
 372
 373         if (line[0] == ' ') {
 374                 if (deferred_old || deferred_new)
 375                         cgit_ssdiff_print_deferred_lines();
 376                 print_ssdiff_line("ctx", current_old_line, line,
 377                                   current_new_line, line, 0);
 378                 current_old_line += 1;
 379                 current_new_line += 1;
 380         } else if (line[0] == '+') {
 381                 deferred_new_add(line, current_new_line);
 382                 current_new_line += 1;
 383         } else if (line[0] == '-') {
 384                 deferred_old_add(line, current_old_line);
 385                 current_old_line += 1;
 386         } else if (line[0] == '@') {
 387                 html("<tr><td colspan='4' class='hunk'>");
 388                 html_txt(line);
 389                 html("</td></tr>");
 390         } else {
 391                 html("<tr><td colspan='4' class='ctx'>");
 392                 html_txt(line);
 393                 html("</td></tr>");
 394         }
 395         line[len - 1] = c;
 396 }
 397
 398 void cgit_ssdiff_header_begin(void)
 399 {
 400         current_old_line = -1;
 401         current_new_line = -1;
 402         html("<tr><td class='space' colspan='4'><div></div></td></tr>");
 403         html("<tr><td class='head' colspan='4'>");
 404 }
 405
 406 void cgit_ssdiff_header_end(void)
 407 {
 408         html("</td><tr>");
 409 }
 410
 411 void cgit_ssdiff_footer(void)
 412 {
 413         if (deferred_old || deferred_new)
 414                 cgit_ssdiff_print_deferred_lines();
 415         html("<tr><td class='foot' colspan='4'></td></tr>");
 416 }