get_tree_entry(): make it available from tree-walk
[git/git.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 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 const unsigned char *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned int *modep)
51 {
52 void *tree = desc->buf;
53 unsigned long size = desc->size;
54 int len = strlen(tree)+1;
55 const unsigned char *sha1 = tree + len;
56 const char *path = strchr(tree, ' ');
57 unsigned int mode;
58
59 if (!path || size < len + 20 || sscanf(tree, "%o", &mode) != 1)
60 die("corrupt tree file");
61 *pathp = path+1;
62 *modep = canon_mode(mode);
63 return sha1;
64 }
65
66 void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callback_t callback)
67 {
68 struct name_entry *entry = xmalloc(n*sizeof(*entry));
69
70 for (;;) {
71 struct name_entry entry[3];
72 unsigned long mask = 0;
73 int i, last;
74
75 last = -1;
76 for (i = 0; i < n; i++) {
77 if (!t[i].size)
78 continue;
79 entry_extract(t+i, entry+i);
80 if (last >= 0) {
81 int cmp = entry_compare(entry+i, entry+last);
82
83 /*
84 * Is the new name bigger than the old one?
85 * Ignore it
86 */
87 if (cmp > 0)
88 continue;
89 /*
90 * Is the new name smaller than the old one?
91 * Ignore all old ones
92 */
93 if (cmp < 0)
94 mask = 0;
95 }
96 mask |= 1ul << i;
97 last = i;
98 }
99 if (!mask)
100 break;
101
102 /*
103 * Update the tree entries we've walked, and clear
104 * all the unused name-entries.
105 */
106 for (i = 0; i < n; i++) {
107 if (mask & (1ul << i)) {
108 update_tree_entry(t+i);
109 continue;
110 }
111 entry_clear(entry + i);
112 }
113 callback(n, mask, entry, base);
114 }
115 free(entry);
116 }
117
118 static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
119 {
120 int namelen = strlen(name);
121 while (t->size) {
122 const char *entry;
123 const unsigned char *sha1;
124 int entrylen, cmp;
125
126 sha1 = tree_entry_extract(t, &entry, mode);
127 update_tree_entry(t);
128 entrylen = strlen(entry);
129 if (entrylen > namelen)
130 continue;
131 cmp = memcmp(name, entry, entrylen);
132 if (cmp > 0)
133 continue;
134 if (cmp < 0)
135 break;
136 if (entrylen == namelen) {
137 memcpy(result, sha1, 20);
138 return 0;
139 }
140 if (name[entrylen] != '/')
141 continue;
142 if (!S_ISDIR(*mode))
143 break;
144 if (++entrylen == namelen) {
145 memcpy(result, sha1, 20);
146 return 0;
147 }
148 return get_tree_entry(sha1, name + entrylen, result, mode);
149 }
150 return -1;
151 }
152
153 int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
154 {
155 int retval;
156 void *tree;
157 struct tree_desc t;
158
159 tree = read_object_with_reference(tree_sha1, tree_type, &t.size, NULL);
160 if (!tree)
161 return -1;
162 t.buf = tree;
163 retval = find_tree_entry(&t, name, sha1, mode);
164 free(tree);
165 return retval;
166 }
167