diff: do not use null sha1 as a sentinel value
[git/git.git] / tree-diff.c
CommitLineData
ac1b3d12
LT
1/*
2 * Helper functions for tree diff generation
3 */
4#include "cache.h"
5#include "diff.h"
750f7b66 6#include "diffcore.h"
8e440259 7#include "tree.h"
ac1b3d12 8
48932677
NTND
9static void show_entry(struct diff_options *opt, const char *prefix,
10 struct tree_desc *desc, struct strbuf *base);
ac1b3d12 11
48932677
NTND
12static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2,
13 struct strbuf *base, struct diff_options *opt)
ac1b3d12
LT
14{
15 unsigned mode1, mode2;
16 const char *path1, *path2;
17 const unsigned char *sha1, *sha2;
18 int cmp, pathlen1, pathlen2;
48932677 19 int old_baselen = base->len;
ac1b3d12 20
50f9a858
LT
21 sha1 = tree_entry_extract(t1, &path1, &mode1);
22 sha2 = tree_entry_extract(t2, &path2, &mode2);
ac1b3d12 23
0de16337
NTND
24 pathlen1 = tree_entry_len(&t1->entry);
25 pathlen2 = tree_entry_len(&t2->entry);
ac1b3d12
LT
26 cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
27 if (cmp < 0) {
48932677 28 show_entry(opt, "-", t1, base);
ac1b3d12
LT
29 return -1;
30 }
31 if (cmp > 0) {
48932677 32 show_entry(opt, "+", t2, base);
ac1b3d12
LT
33 return 1;
34 }
8f67f8ae 35 if (!DIFF_OPT_TST(opt, FIND_COPIES_HARDER) && !hashcmp(sha1, sha2) && mode1 == mode2)
ac1b3d12
LT
36 return 0;
37
38 /*
39 * If the filemode has changed to/from a directory from/to a regular
40 * file, we need to consider it a remove and an add.
41 */
42 if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
48932677
NTND
43 show_entry(opt, "-", t1, base);
44 show_entry(opt, "+", t2, base);
ac1b3d12
LT
45 return 0;
46 }
47
48932677 48 strbuf_add(base, path1, pathlen1);
8f67f8ae 49 if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode1)) {
fd55a19e 50 if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) {
ac1b3d12 51 opt->change(opt, mode1, mode2,
e5450100 52 sha1, sha2, 1, 1, base->buf, 0, 0);
fd55a19e 53 }
48932677 54 strbuf_addch(base, '/');
c0aa335c 55 diff_tree_sha1(sha1, sha2, base->buf, opt);
48932677 56 } else {
e5450100 57 opt->change(opt, mode1, mode2, sha1, sha2, 1, 1, base->buf, 0, 0);
ac1b3d12 58 }
48932677 59 strbuf_setlen(base, old_baselen);
ac1b3d12
LT
60 return 0;
61}
62
ac1b3d12 63/* A whole sub-tree went away or appeared */
48932677
NTND
64static void show_tree(struct diff_options *opt, const char *prefix,
65 struct tree_desc *desc, struct strbuf *base)
ac1b3d12 66{
d688cf07 67 enum interesting match = entry_not_interesting;
97d0b74a 68 for (; desc->size; update_tree_entry(desc)) {
d688cf07 69 if (match != all_entries_interesting) {
97d0b74a
NTND
70 match = tree_entry_interesting(&desc->entry, base, 0,
71 &opt->pathspec);
d688cf07 72 if (match == all_entries_not_interesting)
97d0b74a 73 break;
d688cf07 74 if (match == entry_not_interesting)
97d0b74a 75 continue;
1d848f64 76 }
97d0b74a 77 show_entry(opt, prefix, desc, base);
ac1b3d12
LT
78 }
79}
80
81/* A file entry went away or appeared */
48932677
NTND
82static void show_entry(struct diff_options *opt, const char *prefix,
83 struct tree_desc *desc, struct strbuf *base)
ac1b3d12
LT
84{
85 unsigned mode;
86 const char *path;
50f9a858 87 const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
0de16337 88 int pathlen = tree_entry_len(&desc->entry);
48932677 89 int old_baselen = base->len;
ac1b3d12 90
48932677 91 strbuf_add(base, path, pathlen);
8f67f8ae 92 if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) {
21666f1a 93 enum object_type type;
ac1b3d12
LT
94 struct tree_desc inner;
95 void *tree;
6fda5e51 96 unsigned long size;
ac1b3d12 97
6fda5e51 98 tree = read_sha1_file(sha1, &type, &size);
21666f1a 99 if (!tree || type != OBJ_TREE)
ac1b3d12
LT
100 die("corrupt tree sha %s", sha1_to_hex(sha1));
101
48932677 102 if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE))
e5450100 103 opt->add_remove(opt, *prefix, mode, sha1, 1, base->buf, 0);
df533f34 104
48932677 105 strbuf_addch(base, '/');
ac1b3d12 106
48932677
NTND
107 init_tree_desc(&inner, tree, size);
108 show_tree(opt, prefix, &inner, base);
ac1b3d12 109 free(tree);
48932677 110 } else
e5450100 111 opt->add_remove(opt, prefix[0], mode, sha1, 1, base->buf, 0);
48932677
NTND
112
113 strbuf_setlen(base, old_baselen);
ac1b3d12
LT
114}
115
48932677 116static void skip_uninteresting(struct tree_desc *t, struct strbuf *base,
d688cf07
NTND
117 struct diff_options *opt,
118 enum interesting *match)
5d865017
LT
119{
120 while (t->size) {
97d0b74a
NTND
121 *match = tree_entry_interesting(&t->entry, base, 0, &opt->pathspec);
122 if (*match) {
d688cf07 123 if (*match == all_entries_not_interesting)
97d0b74a
NTND
124 t->size = 0;
125 break;
5d865017 126 }
97d0b74a 127 update_tree_entry(t);
5d865017
LT
128 }
129}
130
48932677
NTND
131int diff_tree(struct tree_desc *t1, struct tree_desc *t2,
132 const char *base_str, struct diff_options *opt)
ac1b3d12 133{
48932677
NTND
134 struct strbuf base;
135 int baselen = strlen(base_str);
d688cf07
NTND
136 enum interesting t1_match = entry_not_interesting;
137 enum interesting t2_match = entry_not_interesting;
304de2d2 138
bc96cc87
NTND
139 /* Enable recursion indefinitely */
140 opt->pathspec.recursive = DIFF_OPT_TST(opt, RECURSIVE);
141 opt->pathspec.max_depth = -1;
142
48932677
NTND
143 strbuf_init(&base, PATH_MAX);
144 strbuf_add(&base, base_str, baselen);
145
5d865017 146 for (;;) {
28b9264d 147 if (diff_can_quit_early(opt))
822cac01 148 break;
66f13625 149 if (opt->pathspec.nr) {
97d0b74a
NTND
150 skip_uninteresting(t1, &base, opt, &t1_match);
151 skip_uninteresting(t2, &base, opt, &t2_match);
ac1b3d12
LT
152 }
153 if (!t1->size) {
5d865017
LT
154 if (!t2->size)
155 break;
48932677 156 show_entry(opt, "+", t2, &base);
ac1b3d12
LT
157 update_tree_entry(t2);
158 continue;
159 }
160 if (!t2->size) {
48932677 161 show_entry(opt, "-", t1, &base);
ac1b3d12
LT
162 update_tree_entry(t1);
163 continue;
164 }
48932677 165 switch (compare_tree_entry(t1, t2, &base, opt)) {
ac1b3d12
LT
166 case -1:
167 update_tree_entry(t1);
168 continue;
169 case 0:
170 update_tree_entry(t1);
171 /* Fallthrough */
172 case 1:
173 update_tree_entry(t2);
174 continue;
175 }
7e44c935 176 die("git diff-tree: internal error");
ac1b3d12 177 }
48932677
NTND
178
179 strbuf_release(&base);
ac1b3d12
LT
180 return 0;
181}
182
750f7b66
LT
183/*
184 * Does it look like the resulting diff might be due to a rename?
185 * - single entry
186 * - not a valid previous file
187 */
188static inline int diff_might_be_rename(void)
189{
190 return diff_queued_diff.nr == 1 &&
191 !DIFF_FILE_VALID(diff_queued_diff.queue[0]->one);
192}
193
194static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
195{
196 struct diff_options diff_opts;
9f38e1ef
LT
197 struct diff_queue_struct *q = &diff_queued_diff;
198 struct diff_filepair *choice;
199 const char *paths[1];
750f7b66
LT
200 int i;
201
9f38e1ef
LT
202 /* Remove the file creation entry from the diff queue, and remember it */
203 choice = q->queue[0];
204 q->nr = 0;
205
750f7b66 206 diff_setup(&diff_opts);
8f67f8ae 207 DIFF_OPT_SET(&diff_opts, RECURSIVE);
0cdca133 208 DIFF_OPT_SET(&diff_opts, FIND_COPIES_HARDER);
750f7b66 209 diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
66f13625 210 diff_opts.single_follow = opt->pathspec.raw[0];
6dd4b66f 211 diff_opts.break_opt = opt->break_opt;
dd98d88b 212 diff_opts.rename_score = opt->rename_score;
750f7b66
LT
213 paths[0] = NULL;
214 diff_tree_setup_paths(paths, &diff_opts);
215 if (diff_setup_done(&diff_opts) < 0)
216 die("unable to set up diff options to follow renames");
217 diff_tree(t1, t2, base, &diff_opts);
218 diffcore_std(&diff_opts);
03b69c76 219 diff_tree_release_paths(&diff_opts);
750f7b66 220
9f38e1ef 221 /* Go through the new set of filepairing, and see if we find a more interesting one */
44c48a90 222 opt->found_follow = 0;
9f38e1ef
LT
223 for (i = 0; i < q->nr; i++) {
224 struct diff_filepair *p = q->queue[i];
750f7b66
LT
225
226 /*
227 * Found a source? Not only do we use that for the new
9f38e1ef 228 * diff_queued_diff, we will also use that as the path in
750f7b66
LT
229 * the future!
230 */
66f13625
NTND
231 if ((p->status == 'R' || p->status == 'C') &&
232 !strcmp(p->two->path, opt->pathspec.raw[0])) {
9f38e1ef
LT
233 /* Switch the file-pairs around */
234 q->queue[i] = choice;
235 choice = p;
236
237 /* Update the path we use from now on.. */
03b69c76 238 diff_tree_release_paths(opt);
66f13625
NTND
239 opt->pathspec.raw[0] = xstrdup(p->one->path);
240 diff_tree_setup_paths(opt->pathspec.raw, opt);
44c48a90
JH
241
242 /*
243 * The caller expects us to return a set of vanilla
244 * filepairs to let a later call to diffcore_std()
245 * it makes to sort the renames out (among other
246 * things), but we already have found renames
247 * ourselves; signal diffcore_std() not to muck with
248 * rename information.
249 */
250 opt->found_follow = 1;
750f7b66
LT
251 break;
252 }
253 }
254
255 /*
3ea3c215 256 * Then, discard all the non-relevant file pairs...
9f38e1ef
LT
257 */
258 for (i = 0; i < q->nr; i++) {
259 struct diff_filepair *p = q->queue[i];
260 diff_free_filepair(p);
261 }
262
263 /*
264 * .. and re-instate the one we want (which might be either the
265 * original one, or the rename/copy we found)
750f7b66 266 */
9f38e1ef
LT
267 q->queue[0] = choice;
268 q->nr = 1;
750f7b66
LT
269}
270
ac1b3d12
LT
271int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
272{
273 void *tree1, *tree2;
274 struct tree_desc t1, t2;
6fda5e51 275 unsigned long size1, size2;
ac1b3d12
LT
276 int retval;
277
6fda5e51 278 tree1 = read_object_with_reference(old, tree_type, &size1, NULL);
ac1b3d12
LT
279 if (!tree1)
280 die("unable to read source tree (%s)", sha1_to_hex(old));
6fda5e51 281 tree2 = read_object_with_reference(new, tree_type, &size2, NULL);
ac1b3d12
LT
282 if (!tree2)
283 die("unable to read destination tree (%s)", sha1_to_hex(new));
6fda5e51
LT
284 init_tree_desc(&t1, tree1, size1);
285 init_tree_desc(&t2, tree2, size2);
ac1b3d12 286 retval = diff_tree(&t1, &t2, base, opt);
39f75d26 287 if (!*base && DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
750f7b66
LT
288 init_tree_desc(&t1, tree1, size1);
289 init_tree_desc(&t2, tree2, size2);
290 try_to_follow_renames(&t1, &t2, base, opt);
291 }
ac1b3d12
LT
292 free(tree1);
293 free(tree2);
294 return retval;
295}
296
2b60356d
RS
297int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
298{
299 int retval;
300 void *tree;
6fda5e51 301 unsigned long size;
2b60356d
RS
302 struct tree_desc empty, real;
303
6fda5e51 304 tree = read_object_with_reference(new, tree_type, &size, NULL);
2b60356d
RS
305 if (!tree)
306 die("unable to read root tree (%s)", sha1_to_hex(new));
6fda5e51 307 init_tree_desc(&real, tree, size);
2b60356d 308
6fda5e51 309 init_tree_desc(&empty, "", 0);
2b60356d
RS
310 retval = diff_tree(&empty, &real, base, opt);
311 free(tree);
312 return retval;
313}
314
a8baa7b9 315void diff_tree_release_paths(struct diff_options *opt)
ac1b3d12 316{
66f13625 317 free_pathspec(&opt->pathspec);
a8baa7b9
JH
318}
319
320void diff_tree_setup_paths(const char **p, struct diff_options *opt)
321{
66f13625 322 init_pathspec(&opt->pathspec, p);
ac1b3d12 323}