Change parent syntax to "xyz^" instead of "xyz.p"
[git] / rev-parse.c
1 /*
2  * rev-parse.c
3  *
4  * Copyright (C) Linus Torvalds, 2005
5  */
6 #include "cache.h"
7 #include "commit.h"
8
9 static int get_extended_sha1(char *name, unsigned char *sha1);
10
11 /*
12  * Some arguments are relevant "revision" arguments,
13  * others are about output format or other details.
14  * This sorts it all out.
15  */
16 static int is_rev_argument(const char *arg)
17 {
18         static const char *rev_args[] = {
19                 "--max-count=",
20                 "--max-age=",
21                 "--min-age=",
22                 "--merge-order",
23                 NULL
24         };
25         const char **p = rev_args;
26
27         for (;;) {
28                 const char *str = *p++;
29                 int len;
30                 if (!str)
31                         return 0;
32                 len = strlen(str);
33                 if (!strncmp(arg, str, len))
34                         return 1;
35         }
36 }
37
38 static int get_parent(char *name, unsigned char *result, int idx)
39 {
40         unsigned char sha1[20];
41         int ret = get_extended_sha1(name, sha1);
42         struct commit *commit;
43         struct commit_list *p;
44
45         if (ret)
46                 return ret;
47         commit = lookup_commit_reference(sha1);
48         if (!commit)
49                 return -1;
50         if (parse_commit(commit))
51                 return -1;
52         p = commit->parents;
53         while (p) {
54                 if (!--idx) {
55                         memcpy(result, p->item->object.sha1, 20);
56                         return 0;
57                 }
58                 p = p->next;
59         }
60         return -1;
61 }
62
63 /*
64  * This is like "get_sha1()", except it allows "sha1 expressions",
65  * notably "xyz^" for "parent of xyz"
66  */
67 static int get_extended_sha1(char *name, unsigned char *sha1)
68 {
69         int parent;
70         int len = strlen(name);
71
72         parent = 1;
73         if (len > 2 && name[len-1] >= '1' && name[len-1] <= '9') {
74                 parent = name[len-1] - '0';
75                 len--;
76         }
77         if (len > 1 && name[len-1] == '^') {
78                 int ret;
79                 name[len-1] = 0;
80                 ret = get_parent(name, sha1, parent);
81                 name[len-1] = '^';
82                 if (!ret)
83                         return 0;
84         }
85         return get_sha1(name, sha1);
86 }
87
88 int main(int argc, char **argv)
89 {
90         int i, as_is = 0, revs_only = 0, no_revs = 0;
91         char *def = NULL;
92         unsigned char sha1[20];
93
94         for (i = 1; i < argc; i++) {
95                 char *arg = argv[i];
96                 char *dotdot;
97         
98                 if (as_is) {
99                         printf("%s\n", arg);
100                         continue;
101                 }
102                 if (*arg == '-') {
103                         if (!strcmp(arg, "--")) {
104                                 if (def) {
105                                         printf("%s\n", def);
106                                         def = NULL;
107                                 }
108                                 if (revs_only)
109                                         break;
110                                 as_is = 1;
111                         }
112                         if (!strcmp(arg, "--default")) {
113                                 if (def)
114                                         printf("%s\n", def);
115                                 def = argv[i+1];
116                                 i++;
117                                 continue;
118                         }
119                         if (!strcmp(arg, "--revs-only")) {
120                                 revs_only = 1;
121                                 continue;
122                         }
123                         if (!strcmp(arg, "--no-revs")) {
124                                 no_revs = 1;
125                                 continue;
126                         }
127                         if (revs_only | no_revs) {
128                                 if (is_rev_argument(arg) != revs_only)
129                                         continue;
130                         }
131                         printf("%s\n", arg);
132                         continue;
133                 }
134                 dotdot = strstr(arg, "..");
135                 if (dotdot) {
136                         unsigned char end[20];
137                         char *n = dotdot+2;
138                         *dotdot = 0;
139                         if (!get_extended_sha1(arg, sha1)) {
140                                 if (!*n)
141                                         n = "HEAD";
142                                 if (!get_extended_sha1(n, end)) {
143                                         if (no_revs)
144                                                 continue;
145                                         def = NULL;
146                                         printf("%s\n", sha1_to_hex(end));
147                                         printf("^%s\n", sha1_to_hex(sha1));
148                                         continue;
149                                 }
150                         }
151                         *dotdot = '.';
152                 }
153                 if (!get_extended_sha1(arg, sha1)) {
154                         if (no_revs)
155                                 continue;
156                         def = NULL;
157                         printf("%s\n", sha1_to_hex(sha1));
158                         continue;
159                 }
160                 if (*arg == '^' && !get_extended_sha1(arg+1, sha1)) {
161                         if (no_revs)
162                                 continue;
163                         def = NULL;
164                         printf("^%s\n", sha1_to_hex(sha1));
165                         continue;
166                 }
167                 if (def) {
168                         printf("%s\n", def);
169                         def = NULL;
170                 }
171                 if (revs_only)
172                         continue;
173                 printf("%s\n", arg);
174         }
175         if (def)
176                 printf("%s\n", def);
177         return 0;
178 }