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[git/mingw/4msysgit.git] / tree-diff.c
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1 /*
2 * Helper functions for tree diff generation
3 */
4 #include "cache.h"
5 #include "diff.h"
6 #include "diffcore.h"
7 #include "tree.h"
9 static void show_entry(struct diff_options *opt, const char *prefix,
10 struct tree_desc *desc, struct strbuf *base);
12 static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2,
13 struct strbuf *base, struct diff_options *opt)
15 unsigned mode1, mode2;
16 const char *path1, *path2;
17 const unsigned char *sha1, *sha2;
18 int cmp, pathlen1, pathlen2;
19 int old_baselen = base->len;
21 sha1 = tree_entry_extract(t1, &path1, &mode1);
22 sha2 = tree_entry_extract(t2, &path2, &mode2);
24 pathlen1 = tree_entry_len(&t1->entry);
25 pathlen2 = tree_entry_len(&t2->entry);
26 cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
27 if (cmp < 0) {
28 show_entry(opt, "-", t1, base);
29 return -1;
31 if (cmp > 0) {
32 show_entry(opt, "+", t2, base);
33 return 1;
35 if (!DIFF_OPT_TST(opt, FIND_COPIES_HARDER) && !hashcmp(sha1, sha2) && mode1 == mode2)
36 return 0;
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.
42 if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
43 show_entry(opt, "-", t1, base);
44 show_entry(opt, "+", t2, base);
45 return 0;
48 strbuf_add(base, path1, pathlen1);
49 if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode1)) {
50 if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) {
51 opt->change(opt, mode1, mode2,
52 sha1, sha2, 1, 1, base->buf, 0, 0);
54 strbuf_addch(base, '/');
55 diff_tree_sha1(sha1, sha2, base->buf, opt);
56 } else {
57 opt->change(opt, mode1, mode2, sha1, sha2, 1, 1, base->buf, 0, 0);
59 strbuf_setlen(base, old_baselen);
60 return 0;
63 /* A whole sub-tree went away or appeared */
64 static void show_tree(struct diff_options *opt, const char *prefix,
65 struct tree_desc *desc, struct strbuf *base)
67 enum interesting match = entry_not_interesting;
68 for (; desc->size; update_tree_entry(desc)) {
69 if (match != all_entries_interesting) {
70 match = tree_entry_interesting(&desc->entry, base, 0,
71 &opt->pathspec);
72 if (match == all_entries_not_interesting)
73 break;
74 if (match == entry_not_interesting)
75 continue;
77 show_entry(opt, prefix, desc, base);
81 /* A file entry went away or appeared */
82 static void show_entry(struct diff_options *opt, const char *prefix,
83 struct tree_desc *desc, struct strbuf *base)
85 unsigned mode;
86 const char *path;
87 const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
88 int pathlen = tree_entry_len(&desc->entry);
89 int old_baselen = base->len;
91 strbuf_add(base, path, pathlen);
92 if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) {
93 enum object_type type;
94 struct tree_desc inner;
95 void *tree;
96 unsigned long size;
98 tree = read_sha1_file(sha1, &type, &size);
99 if (!tree || type != OBJ_TREE)
100 die("corrupt tree sha %s", sha1_to_hex(sha1));
102 if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE))
103 opt->add_remove(opt, *prefix, mode, sha1, 1, base->buf, 0);
105 strbuf_addch(base, '/');
107 init_tree_desc(&inner, tree, size);
108 show_tree(opt, prefix, &inner, base);
109 free(tree);
110 } else
111 opt->add_remove(opt, prefix[0], mode, sha1, 1, base->buf, 0);
113 strbuf_setlen(base, old_baselen);
116 static void skip_uninteresting(struct tree_desc *t, struct strbuf *base,
117 struct diff_options *opt,
118 enum interesting *match)
120 while (t->size) {
121 *match = tree_entry_interesting(&t->entry, base, 0, &opt->pathspec);
122 if (*match) {
123 if (*match == all_entries_not_interesting)
124 t->size = 0;
125 break;
127 update_tree_entry(t);
131 int diff_tree(struct tree_desc *t1, struct tree_desc *t2,
132 const char *base_str, struct diff_options *opt)
134 struct strbuf base;
135 int baselen = strlen(base_str);
136 enum interesting t1_match = entry_not_interesting;
137 enum interesting t2_match = entry_not_interesting;
139 /* Enable recursion indefinitely */
140 opt->pathspec.recursive = DIFF_OPT_TST(opt, RECURSIVE);
142 strbuf_init(&base, PATH_MAX);
143 strbuf_add(&base, base_str, baselen);
145 for (;;) {
146 if (diff_can_quit_early(opt))
147 break;
148 if (opt->pathspec.nr) {
149 skip_uninteresting(t1, &base, opt, &t1_match);
150 skip_uninteresting(t2, &base, opt, &t2_match);
152 if (!t1->size) {
153 if (!t2->size)
154 break;
155 show_entry(opt, "+", t2, &base);
156 update_tree_entry(t2);
157 continue;
159 if (!t2->size) {
160 show_entry(opt, "-", t1, &base);
161 update_tree_entry(t1);
162 continue;
164 switch (compare_tree_entry(t1, t2, &base, opt)) {
165 case -1:
166 update_tree_entry(t1);
167 continue;
168 case 0:
169 update_tree_entry(t1);
170 /* Fallthrough */
171 case 1:
172 update_tree_entry(t2);
173 continue;
175 die("git diff-tree: internal error");
178 strbuf_release(&base);
179 return 0;
183 * Does it look like the resulting diff might be due to a rename?
184 * - single entry
185 * - not a valid previous file
187 static inline int diff_might_be_rename(void)
189 return diff_queued_diff.nr == 1 &&
190 !DIFF_FILE_VALID(diff_queued_diff.queue[0]->one);
193 static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
195 struct diff_options diff_opts;
196 struct diff_queue_struct *q = &diff_queued_diff;
197 struct diff_filepair *choice;
198 int i;
201 * follow-rename code is very specific, we need exactly one
202 * path. Magic that matches more than one path is not
203 * supported.
205 GUARD_PATHSPEC(&opt->pathspec, PATHSPEC_FROMTOP | PATHSPEC_LITERAL);
206 #if 0
208 * We should reject wildcards as well. Unfortunately we
209 * haven't got a reliable way to detect that 'foo\*bar' in
210 * fact has no wildcards. nowildcard_len is merely a hint for
211 * optimization. Let it slip for now until wildmatch is taught
212 * about dry-run mode and returns wildcard info.
214 if (opt->pathspec.has_wildcard)
215 die("BUG:%s:%d: wildcards are not supported",
216 __FILE__, __LINE__);
217 #endif
219 /* Remove the file creation entry from the diff queue, and remember it */
220 choice = q->queue[0];
221 q->nr = 0;
223 diff_setup(&diff_opts);
224 DIFF_OPT_SET(&diff_opts, RECURSIVE);
225 DIFF_OPT_SET(&diff_opts, FIND_COPIES_HARDER);
226 diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
227 diff_opts.single_follow = opt->pathspec.items[0].match;
228 diff_opts.break_opt = opt->break_opt;
229 diff_opts.rename_score = opt->rename_score;
230 diff_setup_done(&diff_opts);
231 diff_tree(t1, t2, base, &diff_opts);
232 diffcore_std(&diff_opts);
233 free_pathspec(&diff_opts.pathspec);
235 /* Go through the new set of filepairing, and see if we find a more interesting one */
236 opt->found_follow = 0;
237 for (i = 0; i < q->nr; i++) {
238 struct diff_filepair *p = q->queue[i];
241 * Found a source? Not only do we use that for the new
242 * diff_queued_diff, we will also use that as the path in
243 * the future!
245 if ((p->status == 'R' || p->status == 'C') &&
246 !strcmp(p->two->path, opt->pathspec.items[0].match)) {
247 const char *path[2];
249 /* Switch the file-pairs around */
250 q->queue[i] = choice;
251 choice = p;
253 /* Update the path we use from now on.. */
254 path[0] = p->one->path;
255 path[1] = NULL;
256 free_pathspec(&opt->pathspec);
257 parse_pathspec(&opt->pathspec,
258 PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
259 PATHSPEC_LITERAL_PATH, "", path);
262 * The caller expects us to return a set of vanilla
263 * filepairs to let a later call to diffcore_std()
264 * it makes to sort the renames out (among other
265 * things), but we already have found renames
266 * ourselves; signal diffcore_std() not to muck with
267 * rename information.
269 opt->found_follow = 1;
270 break;
275 * Then, discard all the non-relevant file pairs...
277 for (i = 0; i < q->nr; i++) {
278 struct diff_filepair *p = q->queue[i];
279 diff_free_filepair(p);
283 * .. and re-instate the one we want (which might be either the
284 * original one, or the rename/copy we found)
286 q->queue[0] = choice;
287 q->nr = 1;
290 int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
292 void *tree1, *tree2;
293 struct tree_desc t1, t2;
294 unsigned long size1, size2;
295 int retval;
297 tree1 = read_object_with_reference(old, tree_type, &size1, NULL);
298 if (!tree1)
299 die("unable to read source tree (%s)", sha1_to_hex(old));
300 tree2 = read_object_with_reference(new, tree_type, &size2, NULL);
301 if (!tree2)
302 die("unable to read destination tree (%s)", sha1_to_hex(new));
303 init_tree_desc(&t1, tree1, size1);
304 init_tree_desc(&t2, tree2, size2);
305 retval = diff_tree(&t1, &t2, base, opt);
306 if (!*base && DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
307 init_tree_desc(&t1, tree1, size1);
308 init_tree_desc(&t2, tree2, size2);
309 try_to_follow_renames(&t1, &t2, base, opt);
311 free(tree1);
312 free(tree2);
313 return retval;
316 int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
318 int retval;
319 void *tree;
320 unsigned long size;
321 struct tree_desc empty, real;
323 tree = read_object_with_reference(new, tree_type, &size, NULL);
324 if (!tree)
325 die("unable to read root tree (%s)", sha1_to_hex(new));
326 init_tree_desc(&real, tree, size);
328 init_tree_desc(&empty, "", 0);
329 retval = diff_tree(&empty, &real, base, opt);
330 free(tree);
331 return retval;