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