ui-ssdiff.c (view raw)
1#include "cgit.h"
2#include "ui-ssdiff.h"
3#include "html.h"
4#include "ui-shared.h"
5#include "ui-diff.h"
6
7extern int use_ssdiff;
8
9static int current_old_line, current_new_line;
10static int **L = NULL;
11
12struct deferred_lines {
13 int line_no;
14 char *line;
15 struct deferred_lines *next;
16};
17
18static struct deferred_lines *deferred_old, *deferred_old_last;
19static struct deferred_lines *deferred_new, *deferred_new_last;
20
21static 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
40static 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
92static 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
113static 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
149static 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
160static 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
174static 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
188static 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
214static 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
279static 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
292static 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
305static 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
340void 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 */
357void 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
391void 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
399void cgit_ssdiff_header_end(void)
400{
401 html("</td><tr>");
402}
403
404void 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}