Merge git://git.kernel.org/pub/scm/git/gitweb
[git] / tree-walk.c
1 #include "cache.h"
2 #include "tree-walk.h"
3 #include "tree.h"
4
5 void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1)
6 {
7         unsigned long size = 0;
8         void *buf = NULL;
9
10         if (sha1) {
11                 buf = read_object_with_reference(sha1, tree_type, &size, NULL);
12                 if (!buf)
13                         die("unable to read tree %s", sha1_to_hex(sha1));
14         }
15         desc->size = size;
16         desc->buf = buf;
17         return buf;
18 }
19
20 static int entry_compare(struct name_entry *a, struct name_entry *b)
21 {
22         return base_name_compare(
23                         a->path, a->pathlen, a->mode,
24                         b->path, b->pathlen, b->mode);
25 }
26
27 static void entry_clear(struct name_entry *a)
28 {
29         memset(a, 0, sizeof(*a));
30 }
31
32 static void entry_extract(struct tree_desc *t, struct name_entry *a)
33 {
34         a->sha1 = tree_entry_extract(t, &a->path, &a->mode);
35         a->pathlen = strlen(a->path);
36 }
37
38 void update_tree_entry(struct tree_desc *desc)
39 {
40         const void *buf = desc->buf;
41         unsigned long size = desc->size;
42         int len = strlen(buf) + 1 + 20;
43
44         if (size < len)
45                 die("corrupt tree file");
46         desc->buf = buf + len;
47         desc->size = size - len;
48 }
49
50 static const char *get_mode(const char *str, unsigned int *modep)
51 {
52         unsigned char c;
53         unsigned int mode = 0;
54
55         while ((c = *str++) != ' ') {
56                 if (c < '0' || c > '7')
57                         return NULL;
58                 mode = (mode << 3) + (c - '0');
59         }
60         *modep = mode;
61         return str;
62 }
63
64 const unsigned char *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned int *modep)
65 {
66         const void *tree = desc->buf;
67         unsigned long size = desc->size;
68         int len = strlen(tree)+1;
69         const unsigned char *sha1 = tree + len;
70         const char *path;
71         unsigned int mode;
72
73         path = get_mode(tree, &mode);
74         if (!path || size < len + 20)
75                 die("corrupt tree file");
76         *pathp = path;
77         *modep = canon_mode(mode);
78         return sha1;
79 }
80
81 int tree_entry(struct tree_desc *desc, struct name_entry *entry)
82 {
83         const void *tree = desc->buf, *path;
84         unsigned long len, size = desc->size;
85
86         if (!size)
87                 return 0;
88
89         path = get_mode(tree, &entry->mode);
90         if (!path)
91                 die("corrupt tree file");
92
93         entry->path = path;
94         len = strlen(path);
95         entry->pathlen = len;
96
97         path += len + 1;
98         entry->sha1 = path;
99
100         path += 20;
101         len = path - tree;
102         if (len > size)
103                 die("corrupt tree file");
104
105         desc->buf = path;
106         desc->size = size - len;
107         return 1;
108 }
109
110 void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callback_t callback)
111 {
112         struct name_entry *entry = xmalloc(n*sizeof(*entry));
113
114         for (;;) {
115                 struct name_entry entry[3];
116                 unsigned long mask = 0;
117                 int i, last;
118
119                 last = -1;
120                 for (i = 0; i < n; i++) {
121                         if (!t[i].size)
122                                 continue;
123                         entry_extract(t+i, entry+i);
124                         if (last >= 0) {
125                                 int cmp = entry_compare(entry+i, entry+last);
126
127                                 /*
128                                  * Is the new name bigger than the old one?
129                                  * Ignore it
130                                  */
131                                 if (cmp > 0)
132                                         continue;
133                                 /*
134                                  * Is the new name smaller than the old one?
135                                  * Ignore all old ones
136                                  */
137                                 if (cmp < 0)
138                                         mask = 0;
139                         }
140                         mask |= 1ul << i;
141                         last = i;
142                 }
143                 if (!mask)
144                         break;
145
146                 /*
147                  * Update the tree entries we've walked, and clear
148                  * all the unused name-entries.
149                  */
150                 for (i = 0; i < n; i++) {
151                         if (mask & (1ul << i)) {
152                                 update_tree_entry(t+i);
153                                 continue;
154                         }
155                         entry_clear(entry + i);
156                 }
157                 callback(n, mask, entry, base);
158         }
159         free(entry);
160 }
161
162 static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
163 {
164         int namelen = strlen(name);
165         while (t->size) {
166                 const char *entry;
167                 const unsigned char *sha1;
168                 int entrylen, cmp;
169
170                 sha1 = tree_entry_extract(t, &entry, mode);
171                 update_tree_entry(t);
172                 entrylen = strlen(entry);
173                 if (entrylen > namelen)
174                         continue;
175                 cmp = memcmp(name, entry, entrylen);
176                 if (cmp > 0)
177                         continue;
178                 if (cmp < 0)
179                         break;
180                 if (entrylen == namelen) {
181                         memcpy(result, sha1, 20);
182                         return 0;
183                 }
184                 if (name[entrylen] != '/')
185                         continue;
186                 if (!S_ISDIR(*mode))
187                         break;
188                 if (++entrylen == namelen) {
189                         memcpy(result, sha1, 20);
190                         return 0;
191                 }
192                 return get_tree_entry(sha1, name + entrylen, result, mode);
193         }
194         return -1;
195 }
196
197 int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
198 {
199         int retval;
200         void *tree;
201         struct tree_desc t;
202
203         tree = read_object_with_reference(tree_sha1, tree_type, &t.size, NULL);
204         if (!tree)
205                 return -1;
206         t.buf = tree;
207         retval = find_tree_entry(&t, name, sha1, mode);
208         free(tree);
209         return retval;
210 }
211