1 /*
2  * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/queue.h>
18 #include <sys/stat.h>
19 
20 #include <sha1.h>
21 #include <string.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <time.h>
25 #include <util.h>
26 #include <zlib.h>
27 
28 #include "got_error.h"
29 #include "got_object.h"
30 #include "got_blame.h"
31 #include "got_opentemp.h"
32 
33 #include "got_lib_inflate.h"
34 #include "got_lib_delta.h"
35 #include "got_lib_object.h"
36 #include "got_lib_diff.h"
37 #include "got_lib_diffoffset.h"
38 
39 struct got_blame_line {
40 	int annotated;
41 	struct got_object_id id;
42 };
43 
44 struct got_blame_diff_offsets {
45 	struct got_diffoffset_chunks *chunks;
46 	struct got_object_id *commit_id;
47 	SLIST_ENTRY(got_blame_diff_offsets) entry;
48 };
49 
50 SLIST_HEAD(got_blame_diff_offsets_list, got_blame_diff_offsets);
51 
52 struct got_blame {
53 	FILE *f;
54 	size_t nlines;
55 	struct got_blame_line *lines; /* one per line */
56 	int ncommits;
57 	struct got_blame_diff_offsets_list diff_offsets_list;
58 };
59 
60 static void
61 free_diff_offsets(struct got_blame_diff_offsets *diff_offsets)
62 {
63 	if (diff_offsets->chunks)
64 		got_diffoffset_free(diff_offsets->chunks);
65 	free(diff_offsets->commit_id);
66 	free(diff_offsets);
67 }
68 
69 static const struct got_error *
70 alloc_diff_offsets(struct got_blame_diff_offsets **diff_offsets,
71     struct got_object_id *commit_id)
72 {
73 	const struct got_error *err = NULL;
74 
75 	*diff_offsets = calloc(1, sizeof(**diff_offsets));
76 	if (*diff_offsets == NULL)
77 		return got_error_from_errno();
78 
79 	(*diff_offsets)->commit_id = got_object_id_dup(commit_id);
80 	if ((*diff_offsets)->commit_id == NULL) {
81 		err = got_error_from_errno();
82 		free_diff_offsets(*diff_offsets);
83 		*diff_offsets = NULL;
84 		return err;
85 	}
86 
87 	err = got_diffoffset_alloc(&(*diff_offsets)->chunks);
88 	if (err) {
89 		free_diff_offsets(*diff_offsets);
90 		return err;
91 	}
92 
93 	return NULL;
94 }
95 
96 static const struct got_error *
97 annotate_line(struct got_blame *blame, int lineno, struct got_object_id *id,
98     const struct got_error *(*cb)(void *, int, int, struct got_object_id *),
99     void *arg)
100 {
101 	const struct got_error *err = NULL;
102 	struct got_blame_line *line;
103 
104 	if (lineno < 1 || lineno > blame->nlines)
105 		return got_error(GOT_ERR_RANGE);
106 	
107 	line = &blame->lines[lineno - 1];
108 	if (line->annotated)
109 		return NULL;
110 
111 	memcpy(&line->id, id, sizeof(line->id));
112 	line->annotated = 1;
113 	if (cb)
114 		err = cb(arg, blame->nlines, lineno, id);
115 	return err;
116 }
117 
118 static int
119 get_blamed_line(struct got_blame_diff_offsets_list *diff_offsets_list,
120     int lineno)
121 {
122 	struct got_blame_diff_offsets *diff_offsets;
123 
124 	SLIST_FOREACH(diff_offsets, diff_offsets_list, entry)
125 		lineno = got_diffoffset_get(diff_offsets->chunks, lineno);
126 
127 	return lineno;
128 }
129 
130 static const struct got_error *
131 blame_changes(struct got_blame *blame, struct got_diff_changes *changes,
132     struct got_object_id *commit_id,
133     const struct got_error *(*cb)(void *, int, int, struct got_object_id *),
134     void *arg)
135 {
136 	const struct got_error *err = NULL;
137 	struct got_diff_change *change;
138 	struct got_blame_diff_offsets *diff_offsets;
139 
140 	SIMPLEQ_FOREACH(change, &changes->entries, entry) {
141 		int c = change->cv.c;
142 		int d = change->cv.d;
143 		int new_lineno = c;
144 		int new_length = (c < d ? d - c + 1 : (c == d ? 1 : 0));
145 		int ln;
146 
147 		for (ln = new_lineno; ln < new_lineno + new_length; ln++) {
148 			err = annotate_line(blame,
149 			    get_blamed_line(&blame->diff_offsets_list, ln),
150 			    commit_id, cb, arg);
151 			if (err)
152 				return err;
153 		}
154 	}
155 
156 	err = alloc_diff_offsets(&diff_offsets, commit_id);
157 	if (err)
158 		return err;
159 	SIMPLEQ_FOREACH(change, &changes->entries, entry) {
160 		int a = change->cv.a;
161 		int b = change->cv.b;
162 		int c = change->cv.c;
163 		int d = change->cv.d;
164 		int old_lineno = a;
165 		int old_length = (a < b ? b - a + 1 : (a == b ? 1 : 0));
166 		int new_lineno = c;
167 		int new_length = (c < d ? d - c + 1 : (c == d ? 1 : 0));
168 
169 		err = got_diffoffset_add(diff_offsets->chunks,
170 		    old_lineno, old_length, new_lineno, new_length);
171 		if (err)
172 			return err;
173 	}
174 	SLIST_INSERT_HEAD(&blame->diff_offsets_list, diff_offsets, entry);
175 
176 	return NULL;
177 }
178 
179 static const struct got_error *
180 blame_commit(struct got_blame *blame, struct got_object_id *id,
181     struct got_object_id *pid, const char *path, struct got_repository *repo,
182     const struct got_error *(*cb)(void *, int, int, struct got_object_id *),
183     void *arg)
184 {
185 	const struct got_error *err = NULL;
186 	struct got_object *obj = NULL, *pobj = NULL;
187 	struct got_blob_object *blob = NULL, *pblob = NULL;
188 	struct got_diff_changes *changes = NULL;
189 
190 	err = got_object_open_by_path(&obj, repo, id, path);
191 	if (err)
192 		goto done;
193 	if (got_object_get_type(obj) != GOT_OBJ_TYPE_BLOB) {
194 		err = got_error(GOT_ERR_OBJ_TYPE);
195 		goto done;
196 	}
197 
198 	err = got_object_open_by_path(&pobj, repo, pid, path);
199 	if (err) {
200 		if (err->code == GOT_ERR_NO_OBJ) {
201 			/* Blob's history began in previous commit. */
202 			err = got_error(GOT_ERR_ITER_COMPLETED);
203 		}
204 		goto done;
205 	}
206 	if (got_object_get_type(pobj) != GOT_OBJ_TYPE_BLOB) {
207 		/*
208 		 * Encountered a non-blob at the path (probably a tree).
209 		 * Blob's history began in previous commit.
210 		 */
211 		err = got_error(GOT_ERR_ITER_COMPLETED);
212 		goto done;
213 	}
214 
215 	/* If blob hashes match then don't bother with diffing. */
216 	if (got_object_id_cmp(&obj->id, &pobj->id) == 0) {
217 		if (cb)
218 			err = cb(arg, blame->nlines, -1, id);
219 		goto done;
220 	}
221 
222 	err = got_object_blob_open(&blob, repo, obj, 8192);
223 	if (err)
224 		goto done;
225 
226 	err = got_object_blob_open(&pblob, repo, pobj, 8192);
227 	if (err)
228 		goto done;
229 
230 	err = got_diff_blob_lines_changed(&changes, pblob, blob);
231 	if (err)
232 		goto done;
233 
234 	if (changes) {
235 		err = blame_changes(blame, changes, id, cb, arg);
236 		got_diff_free_changes(changes);
237 	} else if (cb)
238 		err = cb(arg, blame->nlines, -1, id);
239 done:
240 	if (obj)
241 		got_object_close(obj);
242 	if (pobj)
243 		got_object_close(pobj);
244 	if (blob)
245 		got_object_blob_close(blob);
246 	if (pblob)
247 		got_object_blob_close(pblob);
248 	return err;
249 }
250 
251 static void
252 blame_close(struct got_blame *blame)
253 {
254 	struct got_blame_diff_offsets *diff_offsets;
255 
256 	if (blame->f)
257 		fclose(blame->f);
258 	free(blame->lines);
259 	while (!SLIST_EMPTY(&blame->diff_offsets_list)) {
260 		diff_offsets = SLIST_FIRST(&blame->diff_offsets_list);
261 		SLIST_REMOVE_HEAD(&blame->diff_offsets_list, entry);
262 		free_diff_offsets(diff_offsets);
263 	}
264 	free(blame);
265 }
266 
267 static const struct got_error *
268 blame_open(struct got_blame **blamep, const char *path,
269     struct got_object_id *start_commit_id, struct got_repository *repo,
270     const struct got_error *(*cb)(void *, int, int, struct got_object_id *),
271     void *arg)
272 {
273 	const struct got_error *err = NULL;
274 	struct got_object *obj = NULL;
275 	struct got_blob_object *blob = NULL;
276 	struct got_blame *blame = NULL;
277 	struct got_commit_object *commit = NULL;
278 	struct got_object_id *id = NULL;
279 	int lineno;
280 
281 	*blamep = NULL;
282 
283 	err = got_object_open_by_path(&obj, repo, start_commit_id, path);
284 	if (err)
285 		return err;
286 	if (got_object_get_type(obj) != GOT_OBJ_TYPE_BLOB) {
287 		err = got_error(GOT_ERR_OBJ_TYPE);
288 		goto done;
289 	}
290 
291 	err = got_object_blob_open(&blob, repo, obj, 8192);
292 	if (err)
293 		goto done;
294 
295 	blame = calloc(1, sizeof(*blame));
296 	if (blame == NULL)
297 		return got_error_from_errno();
298 
299 	blame->f = got_opentemp();
300 	if (blame->f == NULL) {
301 		err = got_error_from_errno();
302 		goto done;
303 	}
304 	err = got_object_blob_dump_to_file(NULL, &blame->nlines, blame->f,
305 	    blob);
306 	if (err)
307 		goto done;
308 
309 	blame->lines = calloc(blame->nlines, sizeof(*blame->lines));
310 	if (blame->lines == NULL) {
311 		err = got_error_from_errno();
312 		goto done;
313 	}
314 
315 	/* Loop over first-parent history and try to blame commits. */
316 	err = got_object_open_as_commit(&commit, repo, start_commit_id);
317 	if (err)
318 		goto done;
319 	id = got_object_id_dup(start_commit_id);
320 	if (id == NULL) {
321 		err = got_error_from_errno();
322 		goto done;
323 	}
324 	while (1) {
325 		struct got_object_qid *pid;
326 
327 		pid = SIMPLEQ_FIRST(&commit->parent_ids);
328 		if (pid == NULL)
329 			break;
330 
331 		err = blame_commit(blame, id, pid->id, path, repo, cb, arg);
332 		if (err) {
333 			if (err->code == GOT_ERR_ITER_COMPLETED)
334 				err = NULL;
335 			break;
336 		}
337 
338 		free(id);
339 		id = got_object_id_dup(pid->id);
340 		if (id == NULL) {
341 			err = got_error_from_errno();
342 			goto done;
343 		}
344 		got_object_commit_close(commit);
345 		err = got_object_open_as_commit(&commit, repo, id);
346 		if (err)
347 			goto done;
348 	}
349 
350 	/* Annotate remaining non-annotated lines with last commit. */
351 	for (lineno = 1; lineno <= blame->nlines; lineno++) {
352 		err = annotate_line(blame, lineno, id, cb, arg);
353 		if (err)
354 			goto done;
355 	}
356 
357 done:
358 	free(id);
359 	if (obj)
360 		got_object_close(obj);
361 	if (blob)
362 		got_object_blob_close(blob);
363 	if (commit)
364 		got_object_commit_close(commit);
365 	if (err) {
366 		if (blame)
367 			blame_close(blame);
368 	} else
369 		*blamep = blame;
370 
371 	return err;
372 }
373 
374 static const struct got_error *
375 blame_line(struct got_object_id **id, struct got_blame *blame, int lineno)
376 {
377 	if (lineno < 1 || lineno > blame->nlines)
378 		return got_error(GOT_ERR_RANGE);
379 	*id = &blame->lines[lineno - 1].id;
380 	return NULL;
381 }
382 
383 static char *
384 parse_next_line(FILE *f, size_t *len)
385 {
386 	char *line;
387 	size_t linelen;
388 	size_t lineno;
389 	const char delim[3] = { '\0', '\0', '\0'};
390 
391 	line = fparseln(f, &linelen, &lineno, delim, 0);
392 	if (len)
393 		*len = linelen;
394 	return line;
395 }
396 
397 const struct got_error *
398 got_blame(const char *path, struct got_object_id *start_commit_id,
399     struct got_repository *repo, FILE *outfile)
400 {
401 	const struct got_error *err = NULL;
402 	struct got_blame *blame;
403 	int lineno;
404 	char *abspath;
405 
406 	if (asprintf(&abspath, "%s%s", path[0] == '/' ? "" : "/", path) == -1)
407 		return got_error_from_errno();
408 
409 	err = blame_open(&blame, abspath, start_commit_id, repo, NULL, NULL);
410 	if (err) {
411 		free(abspath);
412 		return err;
413 	}
414 
415 	for (lineno = 1; lineno <= blame->nlines; lineno++) {
416 		struct got_object_id *id;
417 		char *line, *id_str;
418 		
419 		line = parse_next_line(blame->f, NULL);
420 		if (line == NULL)
421 			break;
422 
423 		err = blame_line(&id, blame, lineno);
424 		if (err)
425 			break;
426 
427 		err = got_object_id_str(&id_str, id);
428 		if (err) {
429 			free(line);
430 			break;
431 		}
432 
433 		fprintf(outfile, "%.8s %s\n", id_str, line);
434 		free(line);
435 		free(id_str);
436 	}
437 
438 	blame_close(blame);
439 	free(abspath);
440 	return err;
441 }
442 
443 const struct got_error *
444 got_blame_incremental(const char *path, struct got_object_id *commit_id,
445     struct got_repository *repo,
446     const struct got_error *(*cb)(void *, int, int, struct got_object_id *),
447     void *arg)
448 {
449 	const struct got_error *err = NULL;
450 	struct got_blame *blame;
451 	char *abspath;
452 
453 	if (asprintf(&abspath, "%s%s", path[0] == '/' ? "" : "/", path) == -1)
454 		return got_error_from_errno();
455 
456 	err = blame_open(&blame, abspath, commit_id, repo, cb, arg);
457 	free(abspath);
458 	if (blame)
459 		blame_close(blame);
460 	return err;
461 }