tree-diff: avoid strncmp()
[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"
8e440259 6#include "tree.h"
ac1b3d12 7
304de2d2 8static char *malloc_base(const char *base, int baselen, const char *path, int pathlen)
ac1b3d12 9{
ac1b3d12
LT
10 char *newbase = xmalloc(baselen + pathlen + 2);
11 memcpy(newbase, base, baselen);
12 memcpy(newbase + baselen, path, pathlen);
13 memcpy(newbase + baselen + pathlen, "/", 2);
14 return newbase;
15}
16
cf995ede 17static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
304de2d2 18 const char *base, int baselen);
ac1b3d12 19
304de2d2 20static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, int baselen, struct diff_options *opt)
ac1b3d12
LT
21{
22 unsigned mode1, mode2;
23 const char *path1, *path2;
24 const unsigned char *sha1, *sha2;
25 int cmp, pathlen1, pathlen2;
26
50f9a858
LT
27 sha1 = tree_entry_extract(t1, &path1, &mode1);
28 sha2 = tree_entry_extract(t2, &path2, &mode2);
ac1b3d12 29
304de2d2
LT
30 pathlen1 = tree_entry_len(path1, sha1);
31 pathlen2 = tree_entry_len(path2, sha2);
ac1b3d12
LT
32 cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
33 if (cmp < 0) {
304de2d2 34 show_entry(opt, "-", t1, base, baselen);
ac1b3d12
LT
35 return -1;
36 }
37 if (cmp > 0) {
304de2d2 38 show_entry(opt, "+", t2, base, baselen);
ac1b3d12
LT
39 return 1;
40 }
a89fccd2 41 if (!opt->find_copies_harder && !hashcmp(sha1, sha2) && mode1 == mode2)
ac1b3d12
LT
42 return 0;
43
44 /*
45 * If the filemode has changed to/from a directory from/to a regular
46 * file, we need to consider it a remove and an add.
47 */
48 if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
304de2d2
LT
49 show_entry(opt, "-", t1, base, baselen);
50 show_entry(opt, "+", t2, base, baselen);
ac1b3d12
LT
51 return 0;
52 }
53
54 if (opt->recursive && S_ISDIR(mode1)) {
55 int retval;
304de2d2 56 char *newbase = malloc_base(base, baselen, path1, pathlen1);
ac1b3d12
LT
57 if (opt->tree_in_recursive)
58 opt->change(opt, mode1, mode2,
59 sha1, sha2, base, path1);
60 retval = diff_tree_sha1(sha1, sha2, newbase, opt);
61 free(newbase);
62 return retval;
63 }
64
65 opt->change(opt, mode1, mode2, sha1, sha2, base, path1);
66 return 0;
67}
68
5d865017
LT
69/*
70 * Is a tree entry interesting given the pathspec we have?
71 *
72 * Return:
73 * - positive for yes
74 * - zero for no
75 * - negative for "no, and no subsequent entries will be either"
76 */
77static int tree_entry_interesting(struct tree_desc *desc, const char *base, int baselen, struct diff_options *opt)
ac1b3d12
LT
78{
79 const char *path;
304de2d2 80 const unsigned char *sha1;
ac1b3d12
LT
81 unsigned mode;
82 int i;
304de2d2 83 int pathlen;
7d2f667b 84 int never_interesting = -1;
ac1b3d12 85
a8baa7b9 86 if (!opt->nr_paths)
ac1b3d12
LT
87 return 1;
88
304de2d2 89 sha1 = tree_entry_extract(desc, &path, &mode);
ac1b3d12 90
304de2d2 91 pathlen = tree_entry_len(path, sha1);
ac1b3d12 92
7d2f667b 93 for (i = 0; i < opt->nr_paths; i++) {
a8baa7b9
JH
94 const char *match = opt->paths[i];
95 int matchlen = opt->pathlens[i];
ccc744ab 96 int m = -1; /* signals that we haven't called strncmp() */
ac1b3d12
LT
97
98 if (baselen >= matchlen) {
99 /* If it doesn't match, move along... */
100 if (strncmp(base, match, matchlen))
101 continue;
102
103 /* The base is a subdirectory of a path which was specified. */
104 return 1;
105 }
106
107 /* Does the base match? */
108 if (strncmp(base, match, baselen))
109 continue;
110
111 match += baselen;
112 matchlen -= baselen;
113
ccc744ab
JH
114 if (never_interesting) {
115 /*
116 * We have not seen any match that sorts later
117 * than the current path.
118 */
119
120 /*
121 * Does match sort strictly earlier than path
122 * with their common parts?
123 */
124 m = strncmp(match, path,
125 (matchlen < pathlen) ? matchlen : pathlen);
126 if (m < 0)
127 continue;
7d2f667b 128
ccc744ab
JH
129 /*
130 * If we come here even once, that means there is at
131 * least one pathspec that would sort equal to or
132 * later than the path we are currently looking at.
133 * In other words, if we have never reached this point
134 * after iterating all pathspecs, it means all
135 * pathspecs are either outside of base, or inside the
136 * base but sorts strictly earlier than the current
137 * one. In either case, they will never match the
138 * subsequent entries. In such a case, we initialized
139 * the variable to -1 and that is what will be
140 * returned, allowing the caller to terminate early.
141 */
142 never_interesting = 0;
143 }
7d2f667b 144
ac1b3d12
LT
145 if (pathlen > matchlen)
146 continue;
147
148 if (matchlen > pathlen) {
149 if (match[pathlen] != '/')
150 continue;
151 if (!S_ISDIR(mode))
152 continue;
153 }
154
ccc744ab
JH
155 if (m == -1)
156 /*
157 * we cheated and did not do strncmp(), so we do
158 * that here.
159 */
160 m = strncmp(match, path, pathlen);
161
7d2f667b
JH
162 /*
163 * If common part matched earlier then it is a hit,
164 * because we rejected the case where path is not a
165 * leading directory and is shorter than match.
166 */
167 if (!m)
168 return 1;
ac1b3d12 169 }
7d2f667b 170 return never_interesting; /* No matches */
ac1b3d12
LT
171}
172
173/* A whole sub-tree went away or appeared */
304de2d2 174static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base, int baselen)
ac1b3d12
LT
175{
176 while (desc->size) {
5d865017
LT
177 int show = tree_entry_interesting(desc, base, baselen, opt);
178 if (show < 0)
179 break;
180 if (show)
304de2d2 181 show_entry(opt, prefix, desc, base, baselen);
ac1b3d12
LT
182 update_tree_entry(desc);
183 }
184}
185
186/* A file entry went away or appeared */
cf995ede 187static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
304de2d2 188 const char *base, int baselen)
ac1b3d12
LT
189{
190 unsigned mode;
191 const char *path;
50f9a858 192 const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
ac1b3d12
LT
193
194 if (opt->recursive && S_ISDIR(mode)) {
21666f1a 195 enum object_type type;
304de2d2
LT
196 int pathlen = tree_entry_len(path, sha1);
197 char *newbase = malloc_base(base, baselen, path, pathlen);
ac1b3d12
LT
198 struct tree_desc inner;
199 void *tree;
6fda5e51 200 unsigned long size;
ac1b3d12 201
6fda5e51 202 tree = read_sha1_file(sha1, &type, &size);
21666f1a 203 if (!tree || type != OBJ_TREE)
ac1b3d12
LT
204 die("corrupt tree sha %s", sha1_to_hex(sha1));
205
6fda5e51 206 init_tree_desc(&inner, tree, size);
304de2d2 207 show_tree(opt, prefix, &inner, newbase, baselen + 1 + pathlen);
ac1b3d12
LT
208
209 free(tree);
210 free(newbase);
cf995ede
DR
211 } else {
212 opt->add_remove(opt, prefix[0], mode, sha1, base, path);
ac1b3d12 213 }
ac1b3d12
LT
214}
215
5d865017
LT
216static void skip_uninteresting(struct tree_desc *t, const char *base, int baselen, struct diff_options *opt)
217{
218 while (t->size) {
219 int show = tree_entry_interesting(t, base, baselen, opt);
220 if (!show) {
221 update_tree_entry(t);
222 continue;
223 }
224 /* Skip it all? */
225 if (show < 0)
226 t->size = 0;
227 return;
228 }
229}
230
ac1b3d12
LT
231int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
232{
304de2d2
LT
233 int baselen = strlen(base);
234
5d865017 235 for (;;) {
822cac01
JH
236 if (opt->quiet && opt->has_changes)
237 break;
5d865017
LT
238 if (opt->nr_paths) {
239 skip_uninteresting(t1, base, baselen, opt);
240 skip_uninteresting(t2, base, baselen, opt);
ac1b3d12
LT
241 }
242 if (!t1->size) {
5d865017
LT
243 if (!t2->size)
244 break;
304de2d2 245 show_entry(opt, "+", t2, base, baselen);
ac1b3d12
LT
246 update_tree_entry(t2);
247 continue;
248 }
249 if (!t2->size) {
304de2d2 250 show_entry(opt, "-", t1, base, baselen);
ac1b3d12
LT
251 update_tree_entry(t1);
252 continue;
253 }
304de2d2 254 switch (compare_tree_entry(t1, t2, base, baselen, opt)) {
ac1b3d12
LT
255 case -1:
256 update_tree_entry(t1);
257 continue;
258 case 0:
259 update_tree_entry(t1);
260 /* Fallthrough */
261 case 1:
262 update_tree_entry(t2);
263 continue;
264 }
265 die("git-diff-tree: internal error");
266 }
267 return 0;
268}
269
270int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
271{
272 void *tree1, *tree2;
273 struct tree_desc t1, t2;
6fda5e51 274 unsigned long size1, size2;
ac1b3d12
LT
275 int retval;
276
6fda5e51 277 tree1 = read_object_with_reference(old, tree_type, &size1, NULL);
ac1b3d12
LT
278 if (!tree1)
279 die("unable to read source tree (%s)", sha1_to_hex(old));
6fda5e51 280 tree2 = read_object_with_reference(new, tree_type, &size2, NULL);
ac1b3d12
LT
281 if (!tree2)
282 die("unable to read destination tree (%s)", sha1_to_hex(new));
6fda5e51
LT
283 init_tree_desc(&t1, tree1, size1);
284 init_tree_desc(&t2, tree2, size2);
ac1b3d12
LT
285 retval = diff_tree(&t1, &t2, base, opt);
286 free(tree1);
287 free(tree2);
288 return retval;
289}
290
2b60356d
RS
291int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
292{
293 int retval;
294 void *tree;
6fda5e51 295 unsigned long size;
2b60356d
RS
296 struct tree_desc empty, real;
297
6fda5e51 298 tree = read_object_with_reference(new, tree_type, &size, NULL);
2b60356d
RS
299 if (!tree)
300 die("unable to read root tree (%s)", sha1_to_hex(new));
6fda5e51 301 init_tree_desc(&real, tree, size);
2b60356d 302
6fda5e51 303 init_tree_desc(&empty, "", 0);
2b60356d
RS
304 retval = diff_tree(&empty, &real, base, opt);
305 free(tree);
306 return retval;
307}
308
ac1b3d12
LT
309static int count_paths(const char **paths)
310{
311 int i = 0;
312 while (*paths++)
313 i++;
314 return i;
315}
316
a8baa7b9 317void diff_tree_release_paths(struct diff_options *opt)
ac1b3d12 318{
a8baa7b9
JH
319 free(opt->pathlens);
320}
321
322void diff_tree_setup_paths(const char **p, struct diff_options *opt)
323{
324 opt->nr_paths = 0;
325 opt->pathlens = NULL;
326 opt->paths = NULL;
327
ac1b3d12
LT
328 if (p) {
329 int i;
330
a8baa7b9
JH
331 opt->paths = p;
332 opt->nr_paths = count_paths(p);
333 if (opt->nr_paths == 0) {
334 opt->pathlens = NULL;
7e4a2a84
JH
335 return;
336 }
a8baa7b9
JH
337 opt->pathlens = xmalloc(opt->nr_paths * sizeof(int));
338 for (i=0; i < opt->nr_paths; i++)
339 opt->pathlens[i] = strlen(p[i]);
ac1b3d12
LT
340 }
341}