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;
  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                         strncat(result, prev_buf, cur_buf - prev_buf);
 142                         strncat(result, spaces, 8 - (strlen(result) % 8));
 143                 }
 144                 prev_buf = cur_buf + 1;
 145         }
 146         return result;
 147 }
 148
 149 static int calc_deferred_lines(struct deferred_lines *start)
 150 {
 151         struct deferred_lines *item = start;
 152         int result = 0;
 153         while (item) {
 154                 result += 1;
 155                 item = item->next;
 156         }
 157         return result;
 158 }
 159
 160 static void deferred_old_add(char *line, int line_no)
 161 {
 162         struct deferred_lines *item = xmalloc(sizeof(struct deferred_lines));
 163         item->line = xstrdup(line);
 164         item->line_no = line_no;
 165         item->next = NULL;
 166         if (deferred_old) {
 167                 deferred_old_last->next = item;
 168                 deferred_old_last = item;
 169         } else {
 170                 deferred_old = deferred_old_last = item;
 171         }
 172 }
 173
 174 static void deferred_new_add(char *line, int line_no)
 175 {
 176         struct deferred_lines *item = xmalloc(sizeof(struct deferred_lines));
 177         item->line = xstrdup(line);
 178         item->line_no = line_no;
 179         item->next = NULL;
 180         if (deferred_new) {
 181                 deferred_new_last->next = item;
 182                 deferred_new_last = item;
 183         } else {
 184                 deferred_new = deferred_new_last = item;
 185         }
 186 }
 187
 188 static void print_part_with_lcs(char *class, char *line, char *lcs)
 189 {
 190         int line_len = strlen(line);
 191         int i, j;
 192         char c[2] = " ";
 193         int same = 1;
 194
 195         j = 0;
 196         for (i = 0; i < line_len; i++) {
 197                 c[0] = line[i];
 198                 if (same) {
 199                         if (line[i] == lcs[j])
 200                                 j += 1;
 201                         else {
 202                                 same = 0;
 203                                 htmlf("<span class='%s'>", class);
 204                         }
 205                 } else if (line[i] == lcs[j]) {
 206                         same = 1;
 207                         htmlf("</span>");
 208                         j += 1;
 209                 }
 210                 html_txt(c);
 211         }
 212 }
 213
 214 static void print_ssdiff_line(char *class,
 215                               int old_line_no,
 216                               char *old_line,
 217                               int new_line_no,
 218                               char *new_line, int individual_chars)
 219 {
 220         char *lcs = NULL;
 221
 222         if (old_line)
 223                 old_line = replace_tabs(old_line + 1);
 224         if (new_line)
 225                 new_line = replace_tabs(new_line + 1);
 226         if (individual_chars && old_line && new_line)
 227                 lcs = longest_common_subsequence(old_line, new_line);
 228         html("<tr>\n");
 229         if (old_line_no > 0) {
 230                 struct diff_filespec *old_file = cgit_get_current_old_file();
 231                 char *lineno_str = fmt("n%d", old_line_no);
 232                 char *id_str = fmt("id=%s#%s", is_null_sha1(old_file->sha1)?"HEAD":sha1_to_hex(old_rev_sha1), lineno_str);
 233                 html("<td class='lineno'><a href='");
 234                 html(cgit_fileurl(ctx.repo->url, "tree", old_file->path, id_str));
 235                 htmlf("' id='%s'>%s</a>", lineno_str, lineno_str + 1);
 236                 html("</td>");
 237                 htmlf("<td class='%s'>", class);
 238         } else if (old_line)
 239                 htmlf("<td class='lineno'></td><td class='%s'>", class);
 240         else
 241                 htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
 242         if (old_line) {
 243                 if (lcs)
 244                         print_part_with_lcs("del", old_line, lcs);
 245                 else
 246                         html_txt(old_line);
 247         }
 248
 249         html("</td>\n");
 250         if (new_line_no > 0) {
 251                 struct diff_filespec *new_file = cgit_get_current_new_file();
 252                 char *lineno_str = fmt("n%d", new_line_no);
 253                 char *id_str = fmt("id=%s#%s", is_null_sha1(new_file->sha1)?"HEAD":sha1_to_hex(new_rev_sha1), lineno_str);
 254                 html("<td class='lineno'><a href='");
 255                 html(cgit_fileurl(ctx.repo->url, "tree", new_file->path, id_str));
 256                 htmlf("' id='%s'>%s</a>", lineno_str, lineno_str + 1);
 257                 html("</td>");
 258                 htmlf("<td class='%s'>", class);
 259         } else if (new_line)
 260                 htmlf("<td class='lineno'></td><td class='%s'>", class);
 261         else
 262                 htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
 263         if (new_line) {
 264                 if (lcs)
 265                         print_part_with_lcs("add", new_line, lcs);
 266                 else
 267                         html_txt(new_line);
 268         }
 269
 270         html("</td></tr>");
 271         if (lcs)
 272                 free(lcs);
 273         if (new_line)
 274                 free(new_line);
 275         if (old_line)
 276                 free(old_line);
 277 }
 278
 279 static void print_deferred_old_lines(void)
 280 {
 281         struct deferred_lines *iter_old, *tmp;
 282         iter_old = deferred_old;
 283         while (iter_old) {
 284                 print_ssdiff_line("del", iter_old->line_no,
 285                                   iter_old->line, -1, NULL, 0);
 286                 tmp = iter_old->next;
 287                 free(iter_old);
 288                 iter_old = tmp;
 289         }
 290 }
 291
 292 static void print_deferred_new_lines(void)
 293 {
 294         struct deferred_lines *iter_new, *tmp;
 295         iter_new = deferred_new;
 296         while (iter_new) {
 297                 print_ssdiff_line("add", -1, NULL,
 298                                   iter_new->line_no, iter_new->line, 0);
 299                 tmp = iter_new->next;
 300                 free(iter_new);
 301                 iter_new = tmp;
 302         }
 303 }
 304
 305 static void print_deferred_changed_lines(void)
 306 {
 307         struct deferred_lines *iter_old, *iter_new, *tmp;
 308         int n_old_lines = calc_deferred_lines(deferred_old);
 309         int n_new_lines = calc_deferred_lines(deferred_new);
 310         int individual_chars = (n_old_lines == n_new_lines ? 1 : 0);
 311
 312         iter_old = deferred_old;
 313         iter_new = deferred_new;
 314         while (iter_old || iter_new) {
 315                 if (iter_old && iter_new)
 316                         print_ssdiff_line("changed", iter_old->line_no,
 317                                           iter_old->line,
 318                                           iter_new->line_no, iter_new->line,
 319                                           individual_chars);
 320                 else if (iter_old)
 321                         print_ssdiff_line("changed", iter_old->line_no,
 322                                           iter_old->line, -1, NULL, 0);
 323                 else if (iter_new)
 324                         print_ssdiff_line("changed", -1, NULL,
 325                                           iter_new->line_no, iter_new->line, 0);
 326                 if (iter_old) {
 327                         tmp = iter_old->next;
 328                         free(iter_old);
 329                         iter_old = tmp;
 330                 }
 331
 332                 if (iter_new) {
 333                         tmp = iter_new->next;
 334                         free(iter_new);
 335                         iter_new = tmp;
 336                 }
 337         }
 338 }
 339
 340 void cgit_ssdiff_print_deferred_lines(void)
 341 {
 342         if (!deferred_old && !deferred_new)
 343                 return;
 344         if (deferred_old && !deferred_new)
 345                 print_deferred_old_lines();
 346         else if (!deferred_old && deferred_new)
 347                 print_deferred_new_lines();
 348         else
 349                 print_deferred_changed_lines();
 350         deferred_old = deferred_old_last = NULL;
 351         deferred_new = deferred_new_last = NULL;
 352 }
 353
 354 /*
 355  * print a single line returned from xdiff
 356  */
 357 void cgit_ssdiff_line_cb(char *line, int len)
 358 {
 359         char c = line[len - 1];
 360         line[len - 1] = '\0';
 361         if (line[0] == '@') {
 362                 current_old_line = line_from_hunk(line, '-');
 363                 current_new_line = line_from_hunk(line, '+');
 364         }
 365
 366         if (line[0] == ' ') {
 367                 if (deferred_old || deferred_new)
 368                         cgit_ssdiff_print_deferred_lines();
 369                 print_ssdiff_line("ctx", current_old_line, line,
 370                                   current_new_line, line, 0);
 371                 current_old_line += 1;
 372                 current_new_line += 1;
 373         } else if (line[0] == '+') {
 374                 deferred_new_add(line, current_new_line);
 375                 current_new_line += 1;
 376         } else if (line[0] == '-') {
 377                 deferred_old_add(line, current_old_line);
 378                 current_old_line += 1;
 379         } else if (line[0] == '@') {
 380                 html("<tr><td colspan='4' class='hunk'>");
 381                 html_txt(line);
 382                 html("</td></tr>");
 383         } else {
 384                 html("<tr><td colspan='4' class='ctx'>");
 385                 html_txt(line);
 386                 html("</td></tr>");
 387         }
 388         line[len - 1] = c;
 389 }
 390
 391 void cgit_ssdiff_header_begin(void)
 392 {
 393         current_old_line = -1;
 394         current_new_line = -1;
 395         html("<tr><td class='space' colspan='4'><div></div></td></tr>");
 396         html("<tr><td class='head' colspan='4'>");
 397 }
 398
 399 void cgit_ssdiff_header_end(void)
 400 {
 401         html("</td><tr>");
 402 }
 403
 404 void cgit_ssdiff_footer(void)
 405 {
 406         if (deferred_old || deferred_new)
 407                 cgit_ssdiff_print_deferred_lines();
 408         html("<tr><td class='foot' colspan='4'></td></tr>");
 409 }