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, 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
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_oid(&old_file->oid)?"HEAD":oid_to_hex(old_rev_oid), lineno_str);
233 char *fileurl = cgit_fileurl(ctx.repo->url, "tree", old_file->path, id_str);
234 html("<td class='lineno'><a href='");
235 html(fileurl);
236 htmlf("' id='%s'>%s</a>", lineno_str, lineno_str + 1);
237 html("</td>");
238 htmlf("<td class='%s'>", class);
239 free(fileurl);
240 } else if (old_line)
241 htmlf("<td class='lineno'></td><td class='%s'>", class);
242 else
243 htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
244 if (old_line) {
245 if (lcs)
246 print_part_with_lcs("del", old_line, lcs);
247 else
248 html_txt(old_line);
249 }
250
251 html("</td>\n");
252 if (new_line_no > 0) {
253 struct diff_filespec *new_file = cgit_get_current_new_file();
254 char *lineno_str = fmt("n%d", new_line_no);
255 char *id_str = fmt("id=%s#%s", is_null_oid(&new_file->oid)?"HEAD":oid_to_hex(new_rev_oid), lineno_str);
256 char *fileurl = cgit_fileurl(ctx.repo->url, "tree", new_file->path, id_str);
257 html("<td class='lineno'><a href='");
258 html(fileurl);
259 htmlf("' id='%s'>%s</a>", lineno_str, lineno_str + 1);
260 html("</td>");
261 htmlf("<td class='%s'>", class);
262 free(fileurl);
263 } else if (new_line)
264 htmlf("<td class='lineno'></td><td class='%s'>", class);
265 else
266 htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
267 if (new_line) {
268 if (lcs)
269 print_part_with_lcs("add", new_line, lcs);
270 else
271 html_txt(new_line);
272 }
273
274 html("</td></tr>");
275 if (lcs)
276 free(lcs);
277 if (new_line)
278 free(new_line);
279 if (old_line)
280 free(old_line);
281}
282
283static void print_deferred_old_lines(void)
284{
285 struct deferred_lines *iter_old, *tmp;
286 iter_old = deferred_old;
287 while (iter_old) {
288 print_ssdiff_line("del", iter_old->line_no,
289 iter_old->line, -1, NULL, 0);
290 tmp = iter_old->next;
291 free(iter_old);
292 iter_old = tmp;
293 }
294}
295
296static void print_deferred_new_lines(void)
297{
298 struct deferred_lines *iter_new, *tmp;
299 iter_new = deferred_new;
300 while (iter_new) {
301 print_ssdiff_line("add", -1, NULL,
302 iter_new->line_no, iter_new->line, 0);
303 tmp = iter_new->next;
304 free(iter_new);
305 iter_new = tmp;
306 }
307}
308
309static void print_deferred_changed_lines(void)
310{
311 struct deferred_lines *iter_old, *iter_new, *tmp;
312 int n_old_lines = calc_deferred_lines(deferred_old);
313 int n_new_lines = calc_deferred_lines(deferred_new);
314 int individual_chars = (n_old_lines == n_new_lines ? 1 : 0);
315
316 iter_old = deferred_old;
317 iter_new = deferred_new;
318 while (iter_old || iter_new) {
319 if (iter_old && iter_new)
320 print_ssdiff_line("changed", iter_old->line_no,
321 iter_old->line,
322 iter_new->line_no, iter_new->line,
323 individual_chars);
324 else if (iter_old)
325 print_ssdiff_line("changed", iter_old->line_no,
326 iter_old->line, -1, NULL, 0);
327 else if (iter_new)
328 print_ssdiff_line("changed", -1, NULL,
329 iter_new->line_no, iter_new->line, 0);
330 if (iter_old) {
331 tmp = iter_old->next;
332 free(iter_old);
333 iter_old = tmp;
334 }
335
336 if (iter_new) {
337 tmp = iter_new->next;
338 free(iter_new);
339 iter_new = tmp;
340 }
341 }
342}
343
344void cgit_ssdiff_print_deferred_lines(void)
345{
346 if (!deferred_old && !deferred_new)
347 return;
348 if (deferred_old && !deferred_new)
349 print_deferred_old_lines();
350 else if (!deferred_old && deferred_new)
351 print_deferred_new_lines();
352 else
353 print_deferred_changed_lines();
354 deferred_old = deferred_old_last = NULL;
355 deferred_new = deferred_new_last = NULL;
356}
357
358/*
359 * print a single line returned from xdiff
360 */
361void cgit_ssdiff_line_cb(char *line, int len)
362{
363 char c = line[len - 1];
364 line[len - 1] = '\0';
365 if (line[0] == '@') {
366 current_old_line = line_from_hunk(line, '-');
367 current_new_line = line_from_hunk(line, '+');
368 }
369
370 if (line[0] == ' ') {
371 if (deferred_old || deferred_new)
372 cgit_ssdiff_print_deferred_lines();
373 print_ssdiff_line("ctx", current_old_line, line,
374 current_new_line, line, 0);
375 current_old_line += 1;
376 current_new_line += 1;
377 } else if (line[0] == '+') {
378 deferred_new_add(line, current_new_line);
379 current_new_line += 1;
380 } else if (line[0] == '-') {
381 deferred_old_add(line, current_old_line);
382 current_old_line += 1;
383 } else if (line[0] == '@') {
384 html("<tr><td colspan='4' class='hunk'>");
385 html_txt(line);
386 html("</td></tr>");
387 } else {
388 html("<tr><td colspan='4' class='ctx'>");
389 html_txt(line);
390 html("</td></tr>");
391 }
392 line[len - 1] = c;
393}
394
395void cgit_ssdiff_header_begin(void)
396{
397 current_old_line = -1;
398 current_new_line = -1;
399 html("<tr><td class='space' colspan='4'><div></div></td></tr>");
400 html("<tr><td class='head' colspan='4'>");
401}
402
403void cgit_ssdiff_header_end(void)
404{
405 html("</td><tr>");
406}
407
408void cgit_ssdiff_footer(void)
409{
410 if (deferred_old || deferred_new)
411 cgit_ssdiff_print_deferred_lines();
412 html("<tr><td class='foot' colspan='4'></td></tr>");
413}