2 * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 #include <sys/queue.h>
25 #include "got_error.h"
26 #include "got_repository.h"
27 #include "got_object.h"
29 #include "got_delta_lib.h"
30 #include "got_path_lib.h"
31 #include "got_zbuf_lib.h"
34 #define MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
38 got_delta_open(const char *path_packfile, off_t offset, size_t tslen,
39 int type, size_t size, off_t data_offset)
41 struct got_delta *delta;
43 delta = calloc(1, sizeof(*delta));
47 delta->path_packfile = strdup(path_packfile);
48 if (delta->path_packfile == NULL) {
53 delta->offset = offset;
56 delta->data_offset = data_offset;
61 got_delta_close(struct got_delta *delta)
63 free(delta->path_packfile);
68 const struct got_error *
69 got_delta_chain_get_base_type(int *type, struct got_delta_chain *deltas)
71 struct got_delta *delta;
73 /* The first delta in the chain should represent the base object. */
74 delta = SIMPLEQ_FIRST(&deltas->entries);
75 if (delta->type == GOT_OBJ_TYPE_COMMIT ||
76 delta->type == GOT_OBJ_TYPE_TREE ||
77 delta->type == GOT_OBJ_TYPE_BLOB ||
78 delta->type == GOT_OBJ_TYPE_TAG) {
83 return got_error(GOT_ERR_BAD_DELTA_CHAIN);
86 /* Fetch another (required) byte from the delta stream. */
87 static const struct got_error *
88 next_delta_byte(const uint8_t **p, size_t *remain)
91 return got_error(GOT_ERR_BAD_DELTA);
96 static const struct got_error *
97 parse_size(uint64_t *size, const uint8_t **p, size_t *remain)
99 const struct got_error *err = NULL;
104 /* We do not support size values which don't fit in 64 bit. */
106 return got_error(GOT_ERR_NO_SPACE);
109 *size = ((**p) & GOT_DELTA_SIZE_VAL_MASK);
111 size_t shift = GOT_DELTA_SIZE_SHIFT * i;
112 *size |= (((**p) & GOT_DELTA_SIZE_VAL_MASK) << shift);
115 if (((**p) & GOT_DELTA_SIZE_MORE) == 0)
118 err = next_delta_byte(p, remain);
119 } while (err == NULL);
124 static const struct got_error *
125 parse_opcode(off_t *offset, size_t *len, const uint8_t **p, size_t *remain)
127 const struct got_error *err = NULL;
130 uint8_t opcode = **p;
132 if (opcode & GOT_DELTA_COPY_OFF1) {
133 err = next_delta_byte(p, remain);
138 if (opcode & GOT_DELTA_COPY_OFF2) {
139 err = next_delta_byte(p, remain);
142 o |= ((off_t)(**p)) << 8;
144 if (opcode & GOT_DELTA_COPY_OFF3) {
145 err = next_delta_byte(p, remain);
148 o |= ((off_t)(**p)) << 16;
150 if (opcode & GOT_DELTA_COPY_OFF4) {
151 err = next_delta_byte(p, remain);
154 o |= ((off_t)(**p)) << 24;
157 if (opcode & GOT_DELTA_COPY_LEN1) {
158 err = next_delta_byte(p, remain);
163 if (opcode & GOT_DELTA_COPY_LEN2) {
164 err = next_delta_byte(p, remain);
167 l |= ((off_t)(**p)) << 8;
169 if (opcode & GOT_DELTA_COPY_LEN3) {
170 err = next_delta_byte(p, remain);
173 l |= ((off_t)(**p)) << 16;
177 o = GOT_DELTA_COPY_DEFAULT_OFF;
179 l = GOT_DELTA_COPY_DEFAULT_LEN;
186 static const struct got_error *
187 copy_from_base(FILE *base_file, off_t offset, size_t size, FILE *outfile)
189 if (fseeko(base_file, offset, SEEK_SET) != 0)
190 return got_error_from_errno();
194 size_t len = MIN(size, sizeof(data));
197 n = fread(data, len, 1, base_file);
199 return got_ferror(base_file, GOT_ERR_IO);
201 n = fwrite(data, len, 1, outfile);
203 return got_ferror(outfile, GOT_ERR_IO);
211 static const struct got_error *
212 copy_from_delta(const uint8_t **p, size_t *remain, size_t len, FILE *outfile)
217 return got_error(GOT_ERR_BAD_DELTA);
219 n = fwrite(*p, len, 1, outfile);
221 return got_ferror(outfile, GOT_ERR_IO);
228 const struct got_error *
229 got_delta_apply(FILE *base_file, const uint8_t *delta_buf,
230 size_t delta_len, FILE *outfile)
232 const struct got_error *err = NULL;
233 uint64_t base_size, result_size;
234 size_t remain, outsize = 0;
237 if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
238 return got_error(GOT_ERR_BAD_DELTA);
243 /* Read the two size fields at the beginning of the stream. */
244 err = parse_size(&base_size, &p, &remain);
247 err = next_delta_byte(&p, &remain);
250 err = parse_size(&result_size, &p, &remain);
254 /* Decode and execute copy instructions from the delta stream. */
255 err = next_delta_byte(&p, &remain);
256 while (err == NULL && remain > 0) {
257 if (*p & GOT_DELTA_BASE_COPY) {
260 err = parse_opcode(&offset, &len, &p, &remain);
263 err = copy_from_base(base_file, offset, len, outfile);
272 size_t len = (size_t)*p;
274 err = got_error(GOT_ERR_BAD_DELTA);
277 err = next_delta_byte(&p, &remain);
280 err = copy_from_delta(&p, &remain, len, outfile);
286 if (outsize != result_size)
287 err = got_error(GOT_ERR_BAD_DELTA);