lost-found: make it operable from a subdirectory.
[git/jrn.git] / unpack-objects.c
blobcfd61ae6b08c0635da4044ec3ab09f40c3178632
1 #include "cache.h"
2 #include "object.h"
3 #include "delta.h"
4 #include "pack.h"
6 #include <sys/time.h>
8 static int dry_run, quiet;
9 static const char unpack_usage[] = "git-unpack-objects [-n] [-q] < pack-file";
11 /* We always read in 4kB chunks. */
12 static unsigned char buffer[4096];
13 static unsigned long offset, len, eof;
14 static SHA_CTX ctx;
17 * Make sure at least "min" bytes are available in the buffer, and
18 * return the pointer to the buffer.
20 static void * fill(int min)
22 if (min <= len)
23 return buffer + offset;
24 if (eof)
25 die("unable to fill input");
26 if (min > sizeof(buffer))
27 die("cannot fill %d bytes", min);
28 if (offset) {
29 SHA1_Update(&ctx, buffer, offset);
30 memcpy(buffer, buffer + offset, len);
31 offset = 0;
33 do {
34 int ret = read(0, buffer + len, sizeof(buffer) - len);
35 if (ret <= 0) {
36 if (!ret)
37 die("early EOF");
38 if (errno == EAGAIN || errno == EINTR)
39 continue;
40 die("read error on input: %s", strerror(errno));
42 len += ret;
43 } while (len < min);
44 return buffer;
47 static void use(int bytes)
49 if (bytes > len)
50 die("used more bytes than were available");
51 len -= bytes;
52 offset += bytes;
55 static void *get_data(unsigned long size)
57 z_stream stream;
58 void *buf = xmalloc(size);
60 memset(&stream, 0, sizeof(stream));
62 stream.next_out = buf;
63 stream.avail_out = size;
64 stream.next_in = fill(1);
65 stream.avail_in = len;
66 inflateInit(&stream);
68 for (;;) {
69 int ret = inflate(&stream, 0);
70 use(len - stream.avail_in);
71 if (stream.total_out == size && ret == Z_STREAM_END)
72 break;
73 if (ret != Z_OK)
74 die("inflate returned %d\n", ret);
75 stream.next_in = fill(1);
76 stream.avail_in = len;
78 inflateEnd(&stream);
79 return buf;
82 struct delta_info {
83 unsigned char base_sha1[20];
84 unsigned long size;
85 void *delta;
86 struct delta_info *next;
89 static struct delta_info *delta_list;
91 static void add_delta_to_list(unsigned char *base_sha1, void *delta, unsigned long size)
93 struct delta_info *info = xmalloc(sizeof(*info));
95 memcpy(info->base_sha1, base_sha1, 20);
96 info->size = size;
97 info->delta = delta;
98 info->next = delta_list;
99 delta_list = info;
102 static void added_object(unsigned char *sha1, const char *type, void *data, unsigned long size);
104 static void write_object(void *buf, unsigned long size, const char *type)
106 unsigned char sha1[20];
107 if (write_sha1_file(buf, size, type, sha1) < 0)
108 die("failed to write object");
109 added_object(sha1, type, buf, size);
112 static int resolve_delta(const char *type,
113 void *base, unsigned long base_size,
114 void *delta, unsigned long delta_size)
116 void *result;
117 unsigned long result_size;
119 result = patch_delta(base, base_size,
120 delta, delta_size,
121 &result_size);
122 if (!result)
123 die("failed to apply delta");
124 free(delta);
125 write_object(result, result_size, type);
126 free(result);
127 return 0;
130 static void added_object(unsigned char *sha1, const char *type, void *data, unsigned long size)
132 struct delta_info **p = &delta_list;
133 struct delta_info *info;
135 while ((info = *p) != NULL) {
136 if (!memcmp(info->base_sha1, sha1, 20)) {
137 *p = info->next;
138 p = &delta_list;
139 resolve_delta(type, data, size, info->delta, info->size);
140 free(info);
141 continue;
143 p = &info->next;
147 static int unpack_non_delta_entry(enum object_type kind, unsigned long size)
149 void *buf = get_data(size);
150 const char *type;
152 switch (kind) {
153 case OBJ_COMMIT: type = "commit"; break;
154 case OBJ_TREE: type = "tree"; break;
155 case OBJ_BLOB: type = "blob"; break;
156 case OBJ_TAG: type = "tag"; break;
157 default: die("bad type %d", kind);
159 if (!dry_run)
160 write_object(buf, size, type);
161 free(buf);
162 return 0;
165 static int unpack_delta_entry(unsigned long delta_size)
167 void *delta_data, *base;
168 unsigned long base_size;
169 char type[20];
170 unsigned char base_sha1[20];
171 int result;
173 memcpy(base_sha1, fill(20), 20);
174 use(20);
176 delta_data = get_data(delta_size);
177 if (dry_run) {
178 free(delta_data);
179 return 0;
182 if (!has_sha1_file(base_sha1)) {
183 add_delta_to_list(base_sha1, delta_data, delta_size);
184 return 0;
186 base = read_sha1_file(base_sha1, type, &base_size);
187 if (!base)
188 die("failed to read delta-pack base object %s", sha1_to_hex(base_sha1));
189 result = resolve_delta(type, base, base_size, delta_data, delta_size);
190 free(base);
191 return result;
194 static void unpack_one(unsigned nr, unsigned total)
196 unsigned shift;
197 unsigned char *pack, c;
198 unsigned long size;
199 enum object_type type;
201 pack = fill(1);
202 c = *pack;
203 use(1);
204 type = (c >> 4) & 7;
205 size = (c & 15);
206 shift = 4;
207 while (c & 0x80) {
208 pack = fill(1);
209 c = *pack++;
210 use(1);
211 size += (c & 0x7f) << shift;
212 shift += 7;
214 if (!quiet) {
215 static unsigned long last_sec;
216 static unsigned last_percent;
217 struct timeval now;
218 unsigned percentage = (nr * 100) / total;
220 gettimeofday(&now, NULL);
221 if (percentage != last_percent || now.tv_sec != last_sec) {
222 last_sec = now.tv_sec;
223 last_percent = percentage;
224 fprintf(stderr, "%4u%% (%u/%u) done\r", percentage, nr, total);
227 switch (type) {
228 case OBJ_COMMIT:
229 case OBJ_TREE:
230 case OBJ_BLOB:
231 case OBJ_TAG:
232 unpack_non_delta_entry(type, size);
233 return;
234 case OBJ_DELTA:
235 unpack_delta_entry(size);
236 return;
237 default:
238 die("bad object type %d", type);
243 * We unpack from the end, older files first. Now, usually
244 * there are deltas etc, so we'll not actually write the
245 * objects in that order, but we might as well try..
247 static void unpack_all(void)
249 int i;
250 struct pack_header *hdr = fill(sizeof(struct pack_header));
251 unsigned version = ntohl(hdr->hdr_version);
252 unsigned nr_objects = ntohl(hdr->hdr_entries);
254 if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
255 die("bad pack file");
256 if (version != PACK_VERSION)
257 die("unable to handle pack file version %d", version);
258 fprintf(stderr, "Unpacking %d objects\n", nr_objects);
260 use(sizeof(struct pack_header));
261 for (i = 0; i < nr_objects; i++)
262 unpack_one(i+1, nr_objects);
263 if (delta_list)
264 die("unresolved deltas left after unpacking");
267 int main(int argc, char **argv)
269 int i;
270 unsigned char sha1[20];
272 setup_git_directory();
274 for (i = 1 ; i < argc; i++) {
275 const char *arg = argv[i];
277 if (*arg == '-') {
278 if (!strcmp(arg, "-n")) {
279 dry_run = 1;
280 continue;
282 if (!strcmp(arg, "-q")) {
283 quiet = 1;
284 continue;
286 usage(unpack_usage);
289 /* We don't take any non-flag arguments now.. Maybe some day */
290 usage(unpack_usage);
292 SHA1_Init(&ctx);
293 unpack_all();
294 SHA1_Update(&ctx, buffer, offset);
295 SHA1_Final(sha1, &ctx);
296 if (memcmp(fill(20), sha1, 20))
297 die("final sha1 did not match");
298 use(20);
300 /* Write the last part of the buffer to stdout */
301 while (len) {
302 int ret = write(1, buffer + offset, len);
303 if (!ret)
304 break;
305 if (ret < 0) {
306 if (errno == EAGAIN || errno == EINTR)
307 continue;
308 break;
310 len -= ret;
311 offset += ret;
314 /* All done */
315 if (!quiet)
316 fprintf(stderr, "\n");
317 return 0;