f965f3fc5f66827759223dc9caf63d9abf40ae15
[git/git.git] / revision.h
1 #ifndef REVISION_H
2 #define REVISION_H
3
4 /*
5 * The low 16 bits of the "flags" field shows whether
6 * a commit is part of the path to the root for that
7 * parent.
8 *
9 * Bit 16 is an internal flag that we've seen the
10 * definition for this rev, and not just seen it as
11 * a parent target.
12 */
13 #define marked(rev) ((rev)->flags & 0xffff)
14 #define SEEN 0x10000
15 #define USED 0x20000
16 #define REACHABLE 0x40000
17
18 struct parent {
19 struct revision *parent;
20 struct parent *next;
21 };
22
23 struct revision {
24 unsigned int flags;
25 unsigned char sha1[20];
26 unsigned long date;
27 struct parent *parent;
28 };
29
30 static struct revision **revs;
31 static int nr_revs, rev_allocs;
32
33 static int find_rev(unsigned char *sha1)
34 {
35 int first = 0, last = nr_revs;
36
37 while (first < last) {
38 int next = (first + last) / 2;
39 struct revision *rev = revs[next];
40 int cmp;
41
42 cmp = memcmp(sha1, rev->sha1, 20);
43 if (!cmp)
44 return next;
45 if (cmp < 0) {
46 last = next;
47 continue;
48 }
49 first = next+1;
50 }
51 return -first-1;
52 }
53
54 static struct revision *lookup_rev(unsigned char *sha1)
55 {
56 int pos = find_rev(sha1);
57 struct revision *n;
58
59 if (pos >= 0)
60 return revs[pos];
61
62 pos = -pos-1;
63
64 if (rev_allocs == nr_revs) {
65 rev_allocs = alloc_nr(rev_allocs);
66 revs = realloc(revs, rev_allocs * sizeof(struct revision *));
67 }
68 n = malloc(sizeof(struct revision));
69
70 n->flags = 0;
71 memcpy(n->sha1, sha1, 20);
72 n->parent = NULL;
73
74 /* Insert it into the right place */
75 memmove(revs + pos + 1, revs + pos, (nr_revs - pos) * sizeof(struct revision *));
76 revs[pos] = n;
77 nr_revs++;
78
79 return n;
80 }
81
82 static struct revision *add_relationship(struct revision *rev, unsigned char *needs)
83 {
84 struct revision *parent_rev = lookup_rev(needs);
85 struct parent **pp = &rev->parent, *p;
86
87 while ((p = *pp) != NULL) {
88 if (p->parent == parent_rev)
89 return parent_rev;
90 pp = &p->next;
91 }
92
93 p = malloc(sizeof(*p));
94 p->parent = parent_rev;
95 p->next = NULL;
96 *pp = p;
97 return parent_rev;
98 }
99
100 static void mark_reachable(struct revision *rev, unsigned int mask)
101 {
102 struct parent *p = rev->parent;
103
104 /* If we've been here already, don't bother */
105 if (rev->flags & mask)
106 return;
107 rev->flags |= mask | USED;
108 while (p) {
109 mark_reachable(p->parent, mask);
110 p = p->next;
111 }
112 }
113
114 static unsigned long parse_commit_date(const char *buf)
115 {
116 unsigned long date;
117
118 if (memcmp(buf, "author", 6))
119 return 0;
120 while (*buf++ != '\n')
121 /* nada */;
122 if (memcmp(buf, "committer", 9))
123 return 0;
124 while (*buf++ != '>')
125 /* nada */;
126 date = strtoul(buf, NULL, 10);
127 if (date == ULONG_MAX)
128 date = 0;
129 return date;
130 }
131
132 static int parse_commit(unsigned char *sha1)
133 {
134 struct revision *rev = lookup_rev(sha1);
135
136 if (!(rev->flags & SEEN)) {
137 void *buffer, *bufptr;
138 unsigned long size;
139 char type[20];
140 unsigned char parent[20];
141
142 rev->flags |= SEEN;
143 buffer = bufptr = read_sha1_file(sha1, type, &size);
144 if (!buffer || strcmp(type, "commit"))
145 return -1;
146 bufptr += 46; /* "tree " + "hex sha1" + "\n" */
147 while (!memcmp(bufptr, "parent ", 7) && !get_sha1_hex(bufptr+7, parent)) {
148 add_relationship(rev, parent);
149 parse_commit(parent);
150 bufptr += 48; /* "parent " + "hex sha1" + "\n" */
151 }
152 rev->date = parse_commit_date(bufptr);
153 free(buffer);
154 }
155 return 0;
156 }
157
158 #endif /* REVISION_H */