Implement limited context matching in git-apply.
[git/trast.git] / unpack-objects.c
blob3b824b04a262b92808ba138b1922badbbb25da89
1 #include "cache.h"
2 #include "object.h"
3 #include "delta.h"
4 #include "pack.h"
5 #include "blob.h"
6 #include "commit.h"
7 #include "tag.h"
8 #include "tree.h"
10 #include <sys/time.h>
12 static int dry_run, quiet;
13 static const char unpack_usage[] = "git-unpack-objects [-n] [-q] < pack-file";
15 /* We always read in 4kB chunks. */
16 static unsigned char buffer[4096];
17 static unsigned long offset, len, eof;
18 static SHA_CTX ctx;
21 * Make sure at least "min" bytes are available in the buffer, and
22 * return the pointer to the buffer.
24 static void * fill(int min)
26 if (min <= len)
27 return buffer + offset;
28 if (eof)
29 die("unable to fill input");
30 if (min > sizeof(buffer))
31 die("cannot fill %d bytes", min);
32 if (offset) {
33 SHA1_Update(&ctx, buffer, offset);
34 memcpy(buffer, buffer + offset, len);
35 offset = 0;
37 do {
38 int ret = xread(0, buffer + len, sizeof(buffer) - len);
39 if (ret <= 0) {
40 if (!ret)
41 die("early EOF");
42 die("read error on input: %s", strerror(errno));
44 len += ret;
45 } while (len < min);
46 return buffer;
49 static void use(int bytes)
51 if (bytes > len)
52 die("used more bytes than were available");
53 len -= bytes;
54 offset += bytes;
57 static void *get_data(unsigned long size)
59 z_stream stream;
60 void *buf = xmalloc(size);
62 memset(&stream, 0, sizeof(stream));
64 stream.next_out = buf;
65 stream.avail_out = size;
66 stream.next_in = fill(1);
67 stream.avail_in = len;
68 inflateInit(&stream);
70 for (;;) {
71 int ret = inflate(&stream, 0);
72 use(len - stream.avail_in);
73 if (stream.total_out == size && ret == Z_STREAM_END)
74 break;
75 if (ret != Z_OK)
76 die("inflate returned %d\n", ret);
77 stream.next_in = fill(1);
78 stream.avail_in = len;
80 inflateEnd(&stream);
81 return buf;
84 struct delta_info {
85 unsigned char base_sha1[20];
86 unsigned long size;
87 void *delta;
88 struct delta_info *next;
91 static struct delta_info *delta_list;
93 static void add_delta_to_list(unsigned char *base_sha1, void *delta, unsigned long size)
95 struct delta_info *info = xmalloc(sizeof(*info));
97 memcpy(info->base_sha1, base_sha1, 20);
98 info->size = size;
99 info->delta = delta;
100 info->next = delta_list;
101 delta_list = info;
104 static void added_object(unsigned char *sha1, const char *type, void *data, unsigned long size);
106 static void write_object(void *buf, unsigned long size, const char *type)
108 unsigned char sha1[20];
109 if (write_sha1_file(buf, size, type, sha1) < 0)
110 die("failed to write object");
111 added_object(sha1, type, buf, size);
114 static int resolve_delta(const char *type,
115 void *base, unsigned long base_size,
116 void *delta, unsigned long delta_size)
118 void *result;
119 unsigned long result_size;
121 result = patch_delta(base, base_size,
122 delta, delta_size,
123 &result_size);
124 if (!result)
125 die("failed to apply delta");
126 free(delta);
127 write_object(result, result_size, type);
128 free(result);
129 return 0;
132 static void added_object(unsigned char *sha1, const char *type, void *data, unsigned long size)
134 struct delta_info **p = &delta_list;
135 struct delta_info *info;
137 while ((info = *p) != NULL) {
138 if (!memcmp(info->base_sha1, sha1, 20)) {
139 *p = info->next;
140 p = &delta_list;
141 resolve_delta(type, data, size, info->delta, info->size);
142 free(info);
143 continue;
145 p = &info->next;
149 static int unpack_non_delta_entry(enum object_type kind, unsigned long size)
151 void *buf = get_data(size);
152 const char *type;
154 switch (kind) {
155 case OBJ_COMMIT: type = commit_type; break;
156 case OBJ_TREE: type = tree_type; break;
157 case OBJ_BLOB: type = blob_type; break;
158 case OBJ_TAG: type = tag_type; break;
159 default: die("bad type %d", kind);
161 if (!dry_run)
162 write_object(buf, size, type);
163 free(buf);
164 return 0;
167 static int unpack_delta_entry(unsigned long delta_size)
169 void *delta_data, *base;
170 unsigned long base_size;
171 char type[20];
172 unsigned char base_sha1[20];
173 int result;
175 memcpy(base_sha1, fill(20), 20);
176 use(20);
178 delta_data = get_data(delta_size);
179 if (dry_run) {
180 free(delta_data);
181 return 0;
184 if (!has_sha1_file(base_sha1)) {
185 add_delta_to_list(base_sha1, delta_data, delta_size);
186 return 0;
188 base = read_sha1_file(base_sha1, type, &base_size);
189 if (!base)
190 die("failed to read delta-pack base object %s", sha1_to_hex(base_sha1));
191 result = resolve_delta(type, base, base_size, delta_data, delta_size);
192 free(base);
193 return result;
196 static void unpack_one(unsigned nr, unsigned total)
198 unsigned shift;
199 unsigned char *pack, c;
200 unsigned long size;
201 enum object_type type;
203 pack = fill(1);
204 c = *pack;
205 use(1);
206 type = (c >> 4) & 7;
207 size = (c & 15);
208 shift = 4;
209 while (c & 0x80) {
210 pack = fill(1);
211 c = *pack++;
212 use(1);
213 size += (c & 0x7f) << shift;
214 shift += 7;
216 if (!quiet) {
217 static unsigned long last_sec;
218 static unsigned last_percent;
219 struct timeval now;
220 unsigned percentage = (nr * 100) / total;
222 gettimeofday(&now, NULL);
223 if (percentage != last_percent || now.tv_sec != last_sec) {
224 last_sec = now.tv_sec;
225 last_percent = percentage;
226 fprintf(stderr, "%4u%% (%u/%u) done\r", percentage, nr, total);
229 switch (type) {
230 case OBJ_COMMIT:
231 case OBJ_TREE:
232 case OBJ_BLOB:
233 case OBJ_TAG:
234 unpack_non_delta_entry(type, size);
235 return;
236 case OBJ_DELTA:
237 unpack_delta_entry(size);
238 return;
239 default:
240 die("bad object type %d", type);
245 * We unpack from the end, older files first. Now, usually
246 * there are deltas etc, so we'll not actually write the
247 * objects in that order, but we might as well try..
249 static void unpack_all(void)
251 int i;
252 struct pack_header *hdr = fill(sizeof(struct pack_header));
253 unsigned nr_objects = ntohl(hdr->hdr_entries);
255 if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
256 die("bad pack file");
257 if (!pack_version_ok(hdr->hdr_version))
258 die("unknown pack file version %d", ntohl(hdr->hdr_version));
259 fprintf(stderr, "Unpacking %d objects\n", nr_objects);
261 use(sizeof(struct pack_header));
262 for (i = 0; i < nr_objects; i++)
263 unpack_one(i+1, nr_objects);
264 if (delta_list)
265 die("unresolved deltas left after unpacking");
268 int main(int argc, char **argv)
270 int i;
271 unsigned char sha1[20];
273 setup_git_directory();
275 quiet = !isatty(2);
277 for (i = 1 ; i < argc; i++) {
278 const char *arg = argv[i];
280 if (*arg == '-') {
281 if (!strcmp(arg, "-n")) {
282 dry_run = 1;
283 continue;
285 if (!strcmp(arg, "-q")) {
286 quiet = 1;
287 continue;
289 usage(unpack_usage);
292 /* We don't take any non-flag arguments now.. Maybe some day */
293 usage(unpack_usage);
295 SHA1_Init(&ctx);
296 unpack_all();
297 SHA1_Update(&ctx, buffer, offset);
298 SHA1_Final(sha1, &ctx);
299 if (memcmp(fill(20), sha1, 20))
300 die("final sha1 did not match");
301 use(20);
303 /* Write the last part of the buffer to stdout */
304 while (len) {
305 int ret = xwrite(1, buffer + offset, len);
306 if (ret <= 0)
307 break;
308 len -= ret;
309 offset += ret;
312 /* All done */
313 if (!quiet)
314 fprintf(stderr, "\n");
315 return 0;