Make "--parents" logs also be incremental
[git] / tree-diff.c
1 /*
2  * Helper functions for tree diff generation
3  */
4 #include "cache.h"
5 #include "diff.h"
6 #include "tree.h"
7
8 // What paths are we interested in?
9 static int nr_paths = 0;
10 static const char **paths = NULL;
11 static int *pathlens = NULL;
12
13 static char *malloc_base(const char *base, const char *path, int pathlen)
14 {
15         int baselen = strlen(base);
16         char *newbase = xmalloc(baselen + pathlen + 2);
17         memcpy(newbase, base, baselen);
18         memcpy(newbase + baselen, path, pathlen);
19         memcpy(newbase + baselen + pathlen, "/", 2);
20         return newbase;
21 }
22
23 static int show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base);
24
25 static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
26 {
27         unsigned mode1, mode2;
28         const char *path1, *path2;
29         const unsigned char *sha1, *sha2;
30         int cmp, pathlen1, pathlen2;
31
32         sha1 = tree_entry_extract(t1, &path1, &mode1);
33         sha2 = tree_entry_extract(t2, &path2, &mode2);
34
35         pathlen1 = strlen(path1);
36         pathlen2 = strlen(path2);
37         cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
38         if (cmp < 0) {
39                 show_entry(opt, "-", t1, base);
40                 return -1;
41         }
42         if (cmp > 0) {
43                 show_entry(opt, "+", t2, base);
44                 return 1;
45         }
46         if (!opt->find_copies_harder &&
47             !memcmp(sha1, sha2, 20) && mode1 == mode2)
48                 return 0;
49
50         /*
51          * If the filemode has changed to/from a directory from/to a regular
52          * file, we need to consider it a remove and an add.
53          */
54         if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
55                 show_entry(opt, "-", t1, base);
56                 show_entry(opt, "+", t2, base);
57                 return 0;
58         }
59
60         if (opt->recursive && S_ISDIR(mode1)) {
61                 int retval;
62                 char *newbase = malloc_base(base, path1, pathlen1);
63                 if (opt->tree_in_recursive)
64                         opt->change(opt, mode1, mode2,
65                                     sha1, sha2, base, path1);
66                 retval = diff_tree_sha1(sha1, sha2, newbase, opt);
67                 free(newbase);
68                 return retval;
69         }
70
71         opt->change(opt, mode1, mode2, sha1, sha2, base, path1);
72         return 0;
73 }
74
75 static int interesting(struct tree_desc *desc, const char *base)
76 {
77         const char *path;
78         unsigned mode;
79         int i;
80         int baselen, pathlen;
81
82         if (!nr_paths)
83                 return 1;
84
85         (void)tree_entry_extract(desc, &path, &mode);
86
87         pathlen = strlen(path);
88         baselen = strlen(base);
89
90         for (i=0; i < nr_paths; i++) {
91                 const char *match = paths[i];
92                 int matchlen = pathlens[i];
93
94                 if (baselen >= matchlen) {
95                         /* If it doesn't match, move along... */
96                         if (strncmp(base, match, matchlen))
97                                 continue;
98
99                         /* The base is a subdirectory of a path which was specified. */
100                         return 1;
101                 }
102
103                 /* Does the base match? */
104                 if (strncmp(base, match, baselen))
105                         continue;
106
107                 match += baselen;
108                 matchlen -= baselen;
109
110                 if (pathlen > matchlen)
111                         continue;
112
113                 if (matchlen > pathlen) {
114                         if (match[pathlen] != '/')
115                                 continue;
116                         if (!S_ISDIR(mode))
117                                 continue;
118                 }
119
120                 if (strncmp(path, match, pathlen))
121                         continue;
122
123                 return 1;
124         }
125         return 0; /* No matches */
126 }
127
128 /* A whole sub-tree went away or appeared */
129 static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base)
130 {
131         while (desc->size) {
132                 if (interesting(desc, base))
133                         show_entry(opt, prefix, desc, base);
134                 update_tree_entry(desc);
135         }
136 }
137
138 /* A file entry went away or appeared */
139 static int show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base)
140 {
141         unsigned mode;
142         const char *path;
143         const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
144
145         if (opt->recursive && S_ISDIR(mode)) {
146                 char type[20];
147                 char *newbase = malloc_base(base, path, strlen(path));
148                 struct tree_desc inner;
149                 void *tree;
150
151                 tree = read_sha1_file(sha1, type, &inner.size);
152                 if (!tree || strcmp(type, tree_type))
153                         die("corrupt tree sha %s", sha1_to_hex(sha1));
154
155                 inner.buf = tree;
156                 show_tree(opt, prefix, &inner, newbase);
157
158                 free(tree);
159                 free(newbase);
160                 return 0;
161         }
162
163         opt->add_remove(opt, prefix[0], mode, sha1, base, path);
164         return 0;
165 }
166
167 int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
168 {
169         while (t1->size | t2->size) {
170                 if (nr_paths && t1->size && !interesting(t1, base)) {
171                         update_tree_entry(t1);
172                         continue;
173                 }
174                 if (nr_paths && t2->size && !interesting(t2, base)) {
175                         update_tree_entry(t2);
176                         continue;
177                 }
178                 if (!t1->size) {
179                         show_entry(opt, "+", t2, base);
180                         update_tree_entry(t2);
181                         continue;
182                 }
183                 if (!t2->size) {
184                         show_entry(opt, "-", t1, base);
185                         update_tree_entry(t1);
186                         continue;
187                 }
188                 switch (compare_tree_entry(t1, t2, base, opt)) {
189                 case -1:
190                         update_tree_entry(t1);
191                         continue;
192                 case 0:
193                         update_tree_entry(t1);
194                         /* Fallthrough */
195                 case 1:
196                         update_tree_entry(t2);
197                         continue;
198                 }
199                 die("git-diff-tree: internal error");
200         }
201         return 0;
202 }
203
204 int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
205 {
206         void *tree1, *tree2;
207         struct tree_desc t1, t2;
208         int retval;
209
210         tree1 = read_object_with_reference(old, tree_type, &t1.size, NULL);
211         if (!tree1)
212                 die("unable to read source tree (%s)", sha1_to_hex(old));
213         tree2 = read_object_with_reference(new, tree_type, &t2.size, NULL);
214         if (!tree2)
215                 die("unable to read destination tree (%s)", sha1_to_hex(new));
216         t1.buf = tree1;
217         t2.buf = tree2;
218         retval = diff_tree(&t1, &t2, base, opt);
219         free(tree1);
220         free(tree2);
221         return retval;
222 }
223
224 static int count_paths(const char **paths)
225 {
226         int i = 0;
227         while (*paths++)
228                 i++;
229         return i;
230 }
231
232 void diff_tree_setup_paths(const char **p)
233 {
234         if (p) {
235                 int i;
236
237                 paths = p;
238                 nr_paths = count_paths(paths);
239                 if (nr_paths == 0) {
240                         pathlens = NULL;
241                         return;
242                 }
243                 pathlens = xmalloc(nr_paths * sizeof(int));
244                 for (i=0; i<nr_paths; i++)
245                         pathlens[i] = strlen(paths[i]);
246         }
247 }