Merge branch 'master' into lj/refs
[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 = (char *) 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 = (unsigned char *) 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;
84         const char *path;
85         unsigned long len, size = desc->size;
86
87         if (!size)
88                 return 0;
89
90         path = get_mode(tree, &entry->mode);
91         if (!path)
92                 die("corrupt tree file");
93
94         entry->path = path;
95         len = strlen(path);
96         entry->pathlen = len;
97
98         path += len + 1;
99         entry->sha1 = (const unsigned char *) path;
100
101         path += 20;
102         len = path - (char *) tree;
103         if (len > size)
104                 die("corrupt tree file");
105
106         desc->buf = path;
107         desc->size = size - len;
108         return 1;
109 }
110
111 void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callback_t callback)
112 {
113         struct name_entry *entry = xmalloc(n*sizeof(*entry));
114
115         for (;;) {
116                 struct name_entry entry[3];
117                 unsigned long mask = 0;
118                 int i, last;
119
120                 last = -1;
121                 for (i = 0; i < n; i++) {
122                         if (!t[i].size)
123                                 continue;
124                         entry_extract(t+i, entry+i);
125                         if (last >= 0) {
126                                 int cmp = entry_compare(entry+i, entry+last);
127
128                                 /*
129                                  * Is the new name bigger than the old one?
130                                  * Ignore it
131                                  */
132                                 if (cmp > 0)
133                                         continue;
134                                 /*
135                                  * Is the new name smaller than the old one?
136                                  * Ignore all old ones
137                                  */
138                                 if (cmp < 0)
139                                         mask = 0;
140                         }
141                         mask |= 1ul << i;
142                         last = i;
143                 }
144                 if (!mask)
145                         break;
146
147                 /*
148                  * Update the tree entries we've walked, and clear
149                  * all the unused name-entries.
150                  */
151                 for (i = 0; i < n; i++) {
152                         if (mask & (1ul << i)) {
153                                 update_tree_entry(t+i);
154                                 continue;
155                         }
156                         entry_clear(entry + i);
157                 }
158                 callback(n, mask, entry, base);
159         }
160         free(entry);
161 }
162
163 static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
164 {
165         int namelen = strlen(name);
166         while (t->size) {
167                 const char *entry;
168                 const unsigned char *sha1;
169                 int entrylen, cmp;
170
171                 sha1 = tree_entry_extract(t, &entry, mode);
172                 update_tree_entry(t);
173                 entrylen = strlen(entry);
174                 if (entrylen > namelen)
175                         continue;
176                 cmp = memcmp(name, entry, entrylen);
177                 if (cmp > 0)
178                         continue;
179                 if (cmp < 0)
180                         break;
181                 if (entrylen == namelen) {
182                         hashcpy(result, sha1);
183                         return 0;
184                 }
185                 if (name[entrylen] != '/')
186                         continue;
187                 if (!S_ISDIR(*mode))
188                         break;
189                 if (++entrylen == namelen) {
190                         hashcpy(result, sha1);
191                         return 0;
192                 }
193                 return get_tree_entry(sha1, name + entrylen, result, mode);
194         }
195         return -1;
196 }
197
198 int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
199 {
200         int retval;
201         void *tree;
202         struct tree_desc t;
203
204         tree = read_object_with_reference(tree_sha1, tree_type, &t.size, NULL);
205         if (!tree)
206                 return -1;
207         t.buf = tree;
208         retval = find_tree_entry(&t, name, sha1, mode);
209         free(tree);
210         return retval;
211 }
212