fetch tests: add scaffolding for the new fetch.pruneTags
[git] / bulk-checkin.c
1 /*
2  * Copyright (c) 2011, Google Inc.
3  */
4 #include "cache.h"
5 #include "bulk-checkin.h"
6 #include "csum-file.h"
7 #include "pack.h"
8 #include "strbuf.h"
9 #include "packfile.h"
10
11 static struct bulk_checkin_state {
12         unsigned plugged:1;
13
14         char *pack_tmp_name;
15         struct sha1file *f;
16         off_t offset;
17         struct pack_idx_option pack_idx_opts;
18
19         struct pack_idx_entry **written;
20         uint32_t alloc_written;
21         uint32_t nr_written;
22 } state;
23
24 static void finish_bulk_checkin(struct bulk_checkin_state *state)
25 {
26         struct object_id oid;
27         struct strbuf packname = STRBUF_INIT;
28         int i;
29
30         if (!state->f)
31                 return;
32
33         if (state->nr_written == 0) {
34                 close(state->f->fd);
35                 unlink(state->pack_tmp_name);
36                 goto clear_exit;
37         } else if (state->nr_written == 1) {
38                 sha1close(state->f, oid.hash, CSUM_FSYNC);
39         } else {
40                 int fd = sha1close(state->f, oid.hash, 0);
41                 fixup_pack_header_footer(fd, oid.hash, state->pack_tmp_name,
42                                          state->nr_written, oid.hash,
43                                          state->offset);
44                 close(fd);
45         }
46
47         strbuf_addf(&packname, "%s/pack/pack-", get_object_directory());
48         finish_tmp_packfile(&packname, state->pack_tmp_name,
49                             state->written, state->nr_written,
50                             &state->pack_idx_opts, oid.hash);
51         for (i = 0; i < state->nr_written; i++)
52                 free(state->written[i]);
53
54 clear_exit:
55         free(state->written);
56         memset(state, 0, sizeof(*state));
57
58         strbuf_release(&packname);
59         /* Make objects we just wrote available to ourselves */
60         reprepare_packed_git();
61 }
62
63 static int already_written(struct bulk_checkin_state *state, unsigned char sha1[])
64 {
65         int i;
66
67         /* The object may already exist in the repository */
68         if (has_sha1_file(sha1))
69                 return 1;
70
71         /* Might want to keep the list sorted */
72         for (i = 0; i < state->nr_written; i++)
73                 if (!hashcmp(state->written[i]->oid.hash, sha1))
74                         return 1;
75
76         /* This is a new object we need to keep */
77         return 0;
78 }
79
80 /*
81  * Read the contents from fd for size bytes, streaming it to the
82  * packfile in state while updating the hash in ctx. Signal a failure
83  * by returning a negative value when the resulting pack would exceed
84  * the pack size limit and this is not the first object in the pack,
85  * so that the caller can discard what we wrote from the current pack
86  * by truncating it and opening a new one. The caller will then call
87  * us again after rewinding the input fd.
88  *
89  * The already_hashed_to pointer is kept untouched by the caller to
90  * make sure we do not hash the same byte when we are called
91  * again. This way, the caller does not have to checkpoint its hash
92  * status before calling us just in case we ask it to call us again
93  * with a new pack.
94  */
95 static int stream_to_pack(struct bulk_checkin_state *state,
96                           git_SHA_CTX *ctx, off_t *already_hashed_to,
97                           int fd, size_t size, enum object_type type,
98                           const char *path, unsigned flags)
99 {
100         git_zstream s;
101         unsigned char obuf[16384];
102         unsigned hdrlen;
103         int status = Z_OK;
104         int write_object = (flags & HASH_WRITE_OBJECT);
105         off_t offset = 0;
106
107         git_deflate_init(&s, pack_compression_level);
108
109         hdrlen = encode_in_pack_object_header(obuf, sizeof(obuf), type, size);
110         s.next_out = obuf + hdrlen;
111         s.avail_out = sizeof(obuf) - hdrlen;
112
113         while (status != Z_STREAM_END) {
114                 unsigned char ibuf[16384];
115
116                 if (size && !s.avail_in) {
117                         ssize_t rsize = size < sizeof(ibuf) ? size : sizeof(ibuf);
118                         ssize_t read_result = read_in_full(fd, ibuf, rsize);
119                         if (read_result < 0)
120                                 die_errno("failed to read from '%s'", path);
121                         if (read_result != rsize)
122                                 die("failed to read %d bytes from '%s'",
123                                     (int)rsize, path);
124                         offset += rsize;
125                         if (*already_hashed_to < offset) {
126                                 size_t hsize = offset - *already_hashed_to;
127                                 if (rsize < hsize)
128                                         hsize = rsize;
129                                 if (hsize)
130                                         git_SHA1_Update(ctx, ibuf, hsize);
131                                 *already_hashed_to = offset;
132                         }
133                         s.next_in = ibuf;
134                         s.avail_in = rsize;
135                         size -= rsize;
136                 }
137
138                 status = git_deflate(&s, size ? 0 : Z_FINISH);
139
140                 if (!s.avail_out || status == Z_STREAM_END) {
141                         if (write_object) {
142                                 size_t written = s.next_out - obuf;
143
144                                 /* would we bust the size limit? */
145                                 if (state->nr_written &&
146                                     pack_size_limit_cfg &&
147                                     pack_size_limit_cfg < state->offset + written) {
148                                         git_deflate_abort(&s);
149                                         return -1;
150                                 }
151
152                                 sha1write(state->f, obuf, written);
153                                 state->offset += written;
154                         }
155                         s.next_out = obuf;
156                         s.avail_out = sizeof(obuf);
157                 }
158
159                 switch (status) {
160                 case Z_OK:
161                 case Z_BUF_ERROR:
162                 case Z_STREAM_END:
163                         continue;
164                 default:
165                         die("unexpected deflate failure: %d", status);
166                 }
167         }
168         git_deflate_end(&s);
169         return 0;
170 }
171
172 /* Lazily create backing packfile for the state */
173 static void prepare_to_stream(struct bulk_checkin_state *state,
174                               unsigned flags)
175 {
176         if (!(flags & HASH_WRITE_OBJECT) || state->f)
177                 return;
178
179         state->f = create_tmp_packfile(&state->pack_tmp_name);
180         reset_pack_idx_option(&state->pack_idx_opts);
181
182         /* Pretend we are going to write only one object */
183         state->offset = write_pack_header(state->f, 1);
184         if (!state->offset)
185                 die_errno("unable to write pack header");
186 }
187
188 static int deflate_to_pack(struct bulk_checkin_state *state,
189                            unsigned char result_sha1[],
190                            int fd, size_t size,
191                            enum object_type type, const char *path,
192                            unsigned flags)
193 {
194         off_t seekback, already_hashed_to;
195         git_SHA_CTX ctx;
196         unsigned char obuf[16384];
197         unsigned header_len;
198         struct sha1file_checkpoint checkpoint;
199         struct pack_idx_entry *idx = NULL;
200
201         seekback = lseek(fd, 0, SEEK_CUR);
202         if (seekback == (off_t) -1)
203                 return error("cannot find the current offset");
204
205         header_len = xsnprintf((char *)obuf, sizeof(obuf), "%s %" PRIuMAX,
206                                typename(type), (uintmax_t)size) + 1;
207         git_SHA1_Init(&ctx);
208         git_SHA1_Update(&ctx, obuf, header_len);
209
210         /* Note: idx is non-NULL when we are writing */
211         if ((flags & HASH_WRITE_OBJECT) != 0)
212                 idx = xcalloc(1, sizeof(*idx));
213
214         already_hashed_to = 0;
215
216         while (1) {
217                 prepare_to_stream(state, flags);
218                 if (idx) {
219                         sha1file_checkpoint(state->f, &checkpoint);
220                         idx->offset = state->offset;
221                         crc32_begin(state->f);
222                 }
223                 if (!stream_to_pack(state, &ctx, &already_hashed_to,
224                                     fd, size, type, path, flags))
225                         break;
226                 /*
227                  * Writing this object to the current pack will make
228                  * it too big; we need to truncate it, start a new
229                  * pack, and write into it.
230                  */
231                 if (!idx)
232                         die("BUG: should not happen");
233                 sha1file_truncate(state->f, &checkpoint);
234                 state->offset = checkpoint.offset;
235                 finish_bulk_checkin(state);
236                 if (lseek(fd, seekback, SEEK_SET) == (off_t) -1)
237                         return error("cannot seek back");
238         }
239         git_SHA1_Final(result_sha1, &ctx);
240         if (!idx)
241                 return 0;
242
243         idx->crc32 = crc32_end(state->f);
244         if (already_written(state, result_sha1)) {
245                 sha1file_truncate(state->f, &checkpoint);
246                 state->offset = checkpoint.offset;
247                 free(idx);
248         } else {
249                 hashcpy(idx->oid.hash, result_sha1);
250                 ALLOC_GROW(state->written,
251                            state->nr_written + 1,
252                            state->alloc_written);
253                 state->written[state->nr_written++] = idx;
254         }
255         return 0;
256 }
257
258 int index_bulk_checkin(unsigned char *sha1,
259                        int fd, size_t size, enum object_type type,
260                        const char *path, unsigned flags)
261 {
262         int status = deflate_to_pack(&state, sha1, fd, size, type,
263                                      path, flags);
264         if (!state.plugged)
265                 finish_bulk_checkin(&state);
266         return status;
267 }
268
269 void plug_bulk_checkin(void)
270 {
271         state.plugged = 1;
272 }
273
274 void unplug_bulk_checkin(void)
275 {
276         state.plugged = 0;
277         if (state.f)
278                 finish_bulk_checkin(&state);
279 }