1 /*
2  * Copyright (c) 2017 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 <stdio.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <sha1.h>
24 #include <zlib.h>
25 
26 #include "got_repository.h"
27 #include "got_object.h"
28 #include "got_error.h"
29 
30 #include "diff.h"
31 
32 static const struct got_error *
33 open_tempfile(FILE **sfp, char **sfn)
34 {
35 	static const int sfnlen = 20;
36 	int fd;
37 
38 	*sfn = calloc(sfnlen, sizeof(char));
39 	if (*sfn == NULL)
40 		return got_error(GOT_ERR_NO_MEM);
41 	strlcpy(*sfn, "/tmp/got.XXXXXXXXXX", sfnlen);
42 	if ((fd = mkstemp(*sfn)) == -1 ||
43 	    ((*sfp) = fdopen(fd, "w+")) == NULL) {
44 		if (fd != -1) {
45 			unlink(*sfn);
46 			close(fd);
47 		}
48 		free(*sfn);
49 		return got_error(GOT_ERR_FILE_OPEN);
50 	}
51 	return NULL;
52 }
53 
54 const struct got_error *
55 got_diff_blob(struct got_blob_object *blob1, struct got_blob_object *blob2,
56     const char *label1, const char *label2, FILE *outfile)
57 {
58 	struct got_diff_state ds;
59 	struct got_diff_args args;
60 	const struct got_error *err = NULL;
61 	FILE *f1, *f2;
62 	char *n1, *n2;
63 	size_t len, hdrlen;
64 	char hex1[SHA1_DIGEST_STRING_LENGTH];
65 	char hex2[SHA1_DIGEST_STRING_LENGTH];
66 	int res;
67 
68 	err = open_tempfile(&f1, &n1);
69 	if (err != NULL)
70 		return err;
71 
72 	err = open_tempfile(&f2, &n2);
73 	if (err != NULL) {
74 		fclose(f1);
75 		free(n1);
76 		return err;
77 	}
78 
79 
80 	hdrlen = blob1->hdrlen;
81 	do {
82 		err = got_object_blob_read_block(blob1, &len);
83 		if (err)
84 			goto done;
85 		/* Skip blob object header first time around. */
86 		fwrite(blob1->zb.outbuf + hdrlen, len - hdrlen, 1, f1);
87 		hdrlen = 0;
88 	} while (len != 0);
89 
90 	hdrlen = blob2->hdrlen;
91 	do {
92 		err = got_object_blob_read_block(blob2, &len);
93 		if (err)
94 			goto done;
95 		/* Skip blob object header first time around. */
96 		fwrite(blob2->zb.outbuf + hdrlen, len - hdrlen, 1, f2);
97 		hdrlen = 0;
98 	} while (len != 0);
99 
100 	fflush(f1);
101 	fflush(f2);
102 
103 	memset(&ds, 0, sizeof(ds));
104 	memset(&args, 0, sizeof(args));
105 
106 	args.diff_format = D_UNIFIED;
107 	args.label[0] = label1 ?
108 	    label1 : got_object_id_str(&blob1->id, hex1, sizeof(hex1));
109 	args.label[1] = label2 ?
110 	    label2 : got_object_id_str(&blob2->id, hex2, sizeof(hex2));
111 
112 	err = got_diffreg(&res, n1, n2, 0, &args, &ds);
113 done:
114 	unlink(n1);
115 	unlink(n2);
116 	fclose(f1);
117 	fclose(f2);
118 	free(n1);
119 	free(n2);
120 	return err;
121 }
122 
123 static const struct got_error *
124 match_entry_by_name(struct got_tree_entry **te, struct got_tree_entry *te1,
125     struct got_tree_object *tree2)
126 {
127 	*te = NULL;
128 	return NULL;
129 }
130 
131 static int
132 same_id(struct got_object_id *id1, struct got_object_id *id2)
133 {
134 	return (memcmp(id1->sha1, id2->sha1, SHA1_DIGEST_LENGTH) == 0);
135 }
136 
137 static const struct got_error *
138 diff_added_blob(struct got_object_id *id)
139 {
140 	return NULL;
141 }
142 
143 static const struct got_error *
144 diff_modified_blob(struct got_object_id *id1, struct got_object_id *id2)
145 {
146 	return NULL;
147 }
148 
149 static const struct got_error *
150 diff_deleted_blob(struct got_object_id *id)
151 {
152 	return NULL;
153 }
154 
155 static const struct got_error *
156 diff_added_tree(struct got_object_id *id)
157 {
158 	return NULL;
159 }
160 
161 static const struct got_error *
162 diff_modified_tree(struct got_object_id *id1, struct got_object_id *id2)
163 {
164 	return NULL;
165 }
166 
167 static const struct got_error *
168 diff_deleted_tree(struct got_object_id *id)
169 {
170 	return NULL;
171 }
172 
173 static const struct got_error *
174 diff_kind_mismatch(struct got_object_id *id1, struct got_object_id *id2)
175 {
176 	return NULL;
177 }
178 
179 static const struct got_error *
180 diff_entry_old_new(struct got_tree_entry *te1, struct got_tree_object *tree2)
181 {
182 	const struct got_error *err;
183 	struct got_tree_entry *te2;
184 
185 	err = match_entry_by_name(&te2, te1, tree2);
186 	if (err)
187 		return err;
188 	if (te2 == NULL) {
189 		if (S_ISDIR(te1->mode))
190 			return diff_deleted_tree(&te1->id);
191 		return diff_deleted_blob(&te1->id);
192 	}
193 
194 	if (S_ISDIR(te1->mode) == S_ISDIR(te2->mode)) {
195 		if (!same_id(&te1->id, &te2->id))
196 			return diff_modified_tree(&te1->id, &te2->id);
197 	} else if (S_ISREG(te1->mode) == S_ISREG(te2->mode)) {
198 		if (!same_id(&te1->id, &te2->id))
199 			return diff_modified_blob(&te1->id, &te2->id);
200 	} else
201 		return diff_kind_mismatch(&te1->id, &te2->id);
202 
203 	return NULL;
204 }
205 
206 static const struct got_error *
207 diff_entry_new_old(struct got_tree_entry *te2, struct got_tree_object *tree1)
208 {
209 	const struct got_error *err;
210 	struct got_tree_entry *te1;
211 
212 	err = match_entry_by_name(&te1, te2, tree1);
213 	if (err)
214 		return err;
215 	if (te1 != NULL) /* handled by diff_entry_old_new() */
216 		return NULL;
217 
218 	if (S_ISDIR(te2->mode))
219 		return diff_added_tree(&te2->id);
220 	return diff_added_blob(&te2->id);
221 }
222 
223 const struct got_error *
224 got_diff_tree(struct got_tree_object *tree1, struct got_tree_object *tree2,
225     struct got_repository *repo)
226 {
227 	const struct got_error *err = NULL;
228 	struct got_tree_entry *te1;
229 	struct got_tree_entry *te2;
230 
231 	if (tree1->nentries == 0 && tree2->nentries == 0)
232 		return NULL;
233 
234 	te1 = SIMPLEQ_FIRST(&tree1->entries);
235 	te2 = SIMPLEQ_FIRST(&tree2->entries);
236 
237 	do {
238 		if (te1) {
239 			err = diff_entry_old_new(te1, tree2);
240 			if (err)
241 				break;
242 		}
243 
244 		if (te2) {
245 			err = diff_entry_new_old(te2, tree1);
246 			if (err)
247 				break;
248 		}
249 
250 		if (te1)
251 			te1 = SIMPLEQ_NEXT(te1, entry);
252 		if (te2)
253 			te2 = SIMPLEQ_NEXT(te2, entry);
254 	} while (te1 || te2);
255 
256 	return err;
257 }