git-rev-list: make sure the output is sorted by recency
[git/git.git] / refs.c
CommitLineData
95fc7512
DB
1#include "refs.h"
2#include "cache.h"
3
4#include <errno.h>
5
8a65ff76
LT
6static int read_ref(const char *path, unsigned char *sha1)
7{
8 int ret = -1;
9 int fd = open(path, O_RDONLY);
10
11 if (fd >= 0) {
12 char buffer[60];
13 if (read(fd, buffer, sizeof(buffer)) >= 40)
14 ret = get_sha1_hex(buffer, sha1);
15 close(fd);
16 }
17 return ret;
18}
19
944d8589 20static int do_for_each_ref(const char *base, int (*fn)(const char *path, const unsigned char *sha1))
8a65ff76
LT
21{
22 int retval = 0;
23 DIR *dir = opendir(base);
24
25 if (dir) {
26 struct dirent *de;
27 int baselen = strlen(base);
28 char *path = xmalloc(baselen + 257);
6cada6a9
LT
29
30 if (!strncmp(base, "./", 2)) {
31 base += 2;
32 baselen -= 2;
33 }
8a65ff76 34 memcpy(path, base, baselen);
944d8589
LT
35 if (baselen && base[baselen-1] != '/')
36 path[baselen++] = '/';
8a65ff76
LT
37
38 while ((de = readdir(dir)) != NULL) {
39 unsigned char sha1[20];
40 struct stat st;
41 int namelen;
42
43 if (de->d_name[0] == '.')
44 continue;
45 namelen = strlen(de->d_name);
46 if (namelen > 255)
47 continue;
48 memcpy(path + baselen, de->d_name, namelen+1);
49 if (lstat(path, &st) < 0)
50 continue;
51 if (S_ISDIR(st.st_mode)) {
8a65ff76
LT
52 retval = do_for_each_ref(path, fn);
53 if (retval)
54 break;
55 continue;
56 }
57 if (read_ref(path, sha1) < 0)
58 continue;
59 if (!has_sha1_file(sha1))
60 continue;
61 retval = fn(path, sha1);
62 if (retval)
63 break;
64 }
65 free(path);
66 closedir(dir);
67 }
68 return retval;
69}
70
944d8589 71int for_each_ref(int (*fn)(const char *path, const unsigned char *sha1))
8a65ff76 72{
944d8589 73 return do_for_each_ref(get_refs_directory(), fn);
8a65ff76
LT
74}
75
95fc7512
DB
76static char *ref_file_name(const char *ref)
77{
78 char *base = get_refs_directory();
79 int baselen = strlen(base);
80 int reflen = strlen(ref);
81 char *ret = xmalloc(baselen + 2 + reflen);
82 sprintf(ret, "%s/%s", base, ref);
83 return ret;
84}
85
86static char *ref_lock_file_name(const char *ref)
87{
88 char *base = get_refs_directory();
89 int baselen = strlen(base);
90 int reflen = strlen(ref);
91 char *ret = xmalloc(baselen + 7 + reflen);
92 sprintf(ret, "%s/%s.lock", base, ref);
93 return ret;
94}
95
96static int read_ref_file(const char *filename, unsigned char *sha1) {
97 int fd = open(filename, O_RDONLY);
98 char hex[41];
99 if (fd < 0) {
100 return error("Couldn't open %s\n", filename);
101 }
102 if ((read(fd, hex, 41) < 41) ||
103 (hex[40] != '\n') ||
104 get_sha1_hex(hex, sha1)) {
105 error("Couldn't read a hash from %s\n", filename);
106 close(fd);
107 return -1;
108 }
109 close(fd);
110 return 0;
111}
112
113int get_ref_sha1(const char *ref, unsigned char *sha1)
114{
115 char *filename;
116 int retval;
117 if (check_ref_format(ref))
118 return -1;
119 filename = ref_file_name(ref);
120 retval = read_ref_file(filename, sha1);
121 free(filename);
122 return retval;
123}
124
125static int lock_ref_file(const char *filename, const char *lock_filename,
126 const unsigned char *old_sha1)
127{
128 int fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
129 unsigned char current_sha1[20];
130 int retval;
131 if (fd < 0) {
132 return error("Couldn't open lock file for %s: %s",
133 filename, strerror(errno));
134 }
135 retval = read_ref_file(filename, current_sha1);
136 if (old_sha1) {
137 if (retval) {
138 close(fd);
139 unlink(lock_filename);
140 return error("Could not read the current value of %s",
141 filename);
142 }
143 if (memcmp(current_sha1, old_sha1, 20)) {
144 close(fd);
145 unlink(lock_filename);
146 error("The current value of %s is %s",
147 filename, sha1_to_hex(current_sha1));
148 return error("Expected %s",
149 sha1_to_hex(old_sha1));
150 }
151 } else {
152 if (!retval) {
153 close(fd);
154 unlink(lock_filename);
155 return error("Unexpectedly found a value of %s for %s",
156 sha1_to_hex(current_sha1), filename);
157 }
158 }
159 return fd;
160}
161
162int lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
163{
164 char *filename;
165 char *lock_filename;
166 int retval;
167 if (check_ref_format(ref))
168 return -1;
169 filename = ref_file_name(ref);
170 lock_filename = ref_lock_file_name(ref);
171 retval = lock_ref_file(filename, lock_filename, old_sha1);
172 free(filename);
173 free(lock_filename);
174 return retval;
175}
176
177static int write_ref_file(const char *filename,
178 const char *lock_filename, int fd,
179 const unsigned char *sha1)
180{
181 char *hex = sha1_to_hex(sha1);
182 char term = '\n';
183 if (write(fd, hex, 40) < 40 ||
184 write(fd, &term, 1) < 1) {
185 error("Couldn't write %s\n", filename);
186 close(fd);
187 return -1;
188 }
189 close(fd);
190 rename(lock_filename, filename);
191 return 0;
192}
193
194int write_ref_sha1(const char *ref, int fd, const unsigned char *sha1)
195{
196 char *filename;
197 char *lock_filename;
198 int retval;
199 if (fd < 0)
200 return -1;
201 if (check_ref_format(ref))
202 return -1;
203 filename = ref_file_name(ref);
204 lock_filename = ref_lock_file_name(ref);
205 retval = write_ref_file(filename, lock_filename, fd, sha1);
206 free(filename);
207 free(lock_filename);
208 return retval;
209}
210
211int check_ref_format(const char *ref)
212{
213 char *middle;
214 if (ref[0] == '.' || ref[0] == '/')
215 return -1;
216 middle = strchr(ref, '/');
217 if (!middle || !middle[1])
218 return -1;
219 if (strchr(middle + 1, '/'))
220 return -1;
221 return 0;
222}
223
224int write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1)
225{
226 char *filename;
227 char *lock_filename;
228 int fd;
229 int retval;
230 if (check_ref_format(ref))
231 return -1;
232 filename = ref_file_name(ref);
233 lock_filename = ref_lock_file_name(ref);
234 fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
235 if (fd < 0) {
236 error("Writing %s", lock_filename);
237 perror("Open");
238 }
239 retval = write_ref_file(filename, lock_filename, fd, sha1);
240 free(filename);
241 free(lock_filename);
242 return retval;
243}