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568508e @gitster bulk-checkin: replace fast-import based implementation
gitster authored
1 /*
2 * Copyright (c) 2011, Google Inc.
3 */
4 #include "bulk-checkin.h"
5 #include "csum-file.h"
6 #include "pack.h"
7
8 static int pack_compression_level = Z_DEFAULT_COMPRESSION;
9
10 static struct bulk_checkin_state {
11 unsigned plugged:1;
12
13 char *pack_tmp_name;
14 struct sha1file *f;
15 off_t offset;
16 struct pack_idx_option pack_idx_opts;
17
18 struct pack_idx_entry **written;
19 uint32_t alloc_written;
20 uint32_t nr_written;
21 } state;
22
23 static void finish_bulk_checkin(struct bulk_checkin_state *state)
24 {
25 unsigned char sha1[20];
26 char packname[PATH_MAX];
27 int i;
28
29 if (!state->f)
30 return;
31
32 if (state->nr_written == 0) {
33 close(state->f->fd);
34 unlink(state->pack_tmp_name);
35 goto clear_exit;
36 } else if (state->nr_written == 1) {
37 sha1close(state->f, sha1, CSUM_FSYNC);
38 } else {
39 int fd = sha1close(state->f, sha1, 0);
40 fixup_pack_header_footer(fd, sha1, state->pack_tmp_name,
41 state->nr_written, sha1,
42 state->offset);
43 close(fd);
44 }
45
46 sprintf(packname, "%s/pack/pack-", get_object_directory());
47 finish_tmp_packfile(packname, state->pack_tmp_name,
48 state->written, state->nr_written,
49 &state->pack_idx_opts, sha1);
50 for (i = 0; i < state->nr_written; i++)
51 free(state->written[i]);
52
53 clear_exit:
54 free(state->written);
55 memset(state, 0, sizeof(*state));
56
57 /* Make objects we just wrote available to ourselves */
58 reprepare_packed_git();
59 }
60
61 static int already_written(struct bulk_checkin_state *state, unsigned char sha1[])
62 {
63 int i;
64
65 /* The object may already exist in the repository */
66 if (has_sha1_file(sha1))
67 return 1;
68
69 /* Might want to keep the list sorted */
70 for (i = 0; i < state->nr_written; i++)
71 if (!hashcmp(state->written[i]->sha1, sha1))
72 return 1;
73
74 /* This is a new object we need to keep */
75 return 0;
76 }
77
78 /*
79 * Read the contents from fd for size bytes, streaming it to the
80 * packfile in state while updating the hash in ctx. Signal a failure
81 * by returning a negative value when the resulting pack would exceed
82 * the pack size limit and this is not the first object in the pack,
83 * so that the caller can discard what we wrote from the current pack
84 * by truncating it and opening a new one. The caller will then call
85 * us again after rewinding the input fd.
86 *
87 * The already_hashed_to pointer is kept untouched by the caller to
88 * make sure we do not hash the same byte when we are called
89 * again. This way, the caller does not have to checkpoint its hash
90 * status before calling us just in case we ask it to call us again
91 * with a new pack.
92 */
93 static int stream_to_pack(struct bulk_checkin_state *state,
94 git_SHA_CTX *ctx, off_t *already_hashed_to,
95 int fd, size_t size, enum object_type type,
96 const char *path, unsigned flags)
97 {
98 git_zstream s;
99 unsigned char obuf[16384];
100 unsigned hdrlen;
101 int status = Z_OK;
102 int write_object = (flags & HASH_WRITE_OBJECT);
103 off_t offset = 0;
104
105 memset(&s, 0, sizeof(s));
106 git_deflate_init(&s, pack_compression_level);
107
108 hdrlen = encode_in_pack_object_header(type, size, obuf);
109 s.next_out = obuf + hdrlen;
110 s.avail_out = sizeof(obuf) - hdrlen;
111
112 while (status != Z_STREAM_END) {
113 unsigned char ibuf[16384];
114
115 if (size && !s.avail_in) {
116 ssize_t rsize = size < sizeof(ibuf) ? size : sizeof(ibuf);
117 if (xread(fd, ibuf, rsize) != rsize)
118 die("failed to read %d bytes from '%s'",
119 (int)rsize, path);
120 offset += rsize;
121 if (*already_hashed_to < offset) {
122 size_t hsize = offset - *already_hashed_to;
123 if (rsize < hsize)
124 hsize = rsize;
125 if (hsize)
126 git_SHA1_Update(ctx, ibuf, hsize);
127 *already_hashed_to = offset;
128 }
129 s.next_in = ibuf;
130 s.avail_in = rsize;
131 size -= rsize;
132 }
133
134 status = git_deflate(&s, size ? 0 : Z_FINISH);
135
136 if (!s.avail_out || status == Z_STREAM_END) {
137 if (write_object) {
138 size_t written = s.next_out - obuf;
139
140 /* would we bust the size limit? */
141 if (state->nr_written &&
142 pack_size_limit_cfg &&
143 pack_size_limit_cfg < state->offset + written) {
144 git_deflate_abort(&s);
145 return -1;
146 }
147
148 sha1write(state->f, obuf, written);
149 state->offset += written;
150 }
151 s.next_out = obuf;
152 s.avail_out = sizeof(obuf);
153 }
154
155 switch (status) {
156 case Z_OK:
157 case Z_BUF_ERROR:
158 case Z_STREAM_END:
159 continue;
160 default:
161 die("unexpected deflate failure: %d", status);
162 }
163 }
164 git_deflate_end(&s);
165 return 0;
166 }
167
168 /* Lazily create backing packfile for the state */
169 static void prepare_to_stream(struct bulk_checkin_state *state,
170 unsigned flags)
171 {
172 if (!(flags & HASH_WRITE_OBJECT) || state->f)
173 return;
174
175 state->f = create_tmp_packfile(&state->pack_tmp_name);
176 reset_pack_idx_option(&state->pack_idx_opts);
177
178 /* Pretend we are going to write only one object */
179 state->offset = write_pack_header(state->f, 1);
180 if (!state->offset)
181 die_errno("unable to write pack header");
182 }
183
184 static int deflate_to_pack(struct bulk_checkin_state *state,
185 unsigned char result_sha1[],
186 int fd, size_t size,
187 enum object_type type, const char *path,
188 unsigned flags)
189 {
190 off_t seekback, already_hashed_to;
191 git_SHA_CTX ctx;
192 unsigned char obuf[16384];
193 unsigned header_len;
194 struct sha1file_checkpoint checkpoint;
195 struct pack_idx_entry *idx = NULL;
196
197 seekback = lseek(fd, 0, SEEK_CUR);
198 if (seekback == (off_t) -1)
199 return error("cannot find the current offset");
200
201 header_len = sprintf((char *)obuf, "%s %" PRIuMAX,
202 typename(type), (uintmax_t)size) + 1;
203 git_SHA1_Init(&ctx);
204 git_SHA1_Update(&ctx, obuf, header_len);
205
206 /* Note: idx is non-NULL when we are writing */
207 if ((flags & HASH_WRITE_OBJECT) != 0)
208 idx = xcalloc(1, sizeof(*idx));
209
210 already_hashed_to = 0;
211
212 while (1) {
213 prepare_to_stream(state, flags);
214 if (idx) {
215 sha1file_checkpoint(state->f, &checkpoint);
216 idx->offset = state->offset;
217 crc32_begin(state->f);
218 }
219 if (!stream_to_pack(state, &ctx, &already_hashed_to,
220 fd, size, type, path, flags))
221 break;
222 /*
223 * Writing this object to the current pack will make
224 * it too big; we need to truncate it, start a new
225 * pack, and write into it.
226 */
227 if (!idx)
228 die("BUG: should not happen");
229 sha1file_truncate(state->f, &checkpoint);
230 state->offset = checkpoint.offset;
231 finish_bulk_checkin(state);
232 if (lseek(fd, seekback, SEEK_SET) == (off_t) -1)
233 return error("cannot seek back");
234 }
235 git_SHA1_Final(result_sha1, &ctx);
236 if (!idx)
237 return 0;
238
239 idx->crc32 = crc32_end(state->f);
240 if (already_written(state, result_sha1)) {
241 sha1file_truncate(state->f, &checkpoint);
242 state->offset = checkpoint.offset;
243 free(idx);
244 } else {
245 hashcpy(idx->sha1, result_sha1);
246 ALLOC_GROW(state->written,
247 state->nr_written + 1,
248 state->alloc_written);
249 state->written[state->nr_written++] = idx;
250 }
251 return 0;
252 }
253
254 int index_bulk_checkin(unsigned char *sha1,
255 int fd, size_t size, enum object_type type,
256 const char *path, unsigned flags)
257 {
258 int status = deflate_to_pack(&state, sha1, fd, size, type,
259 path, flags);
260 if (!state.plugged)
261 finish_bulk_checkin(&state);
262 return status;
263 }
264
265 void plug_bulk_checkin(void)
266 {
267 state.plugged = 1;
268 }
269
270 void unplug_bulk_checkin(void)
271 {
272 state.plugged = 0;
273 if (state.f)
274 finish_bulk_checkin(&state);
275 }
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