avoid looking at errno for short read_in_full() returns
[git/git.git] / bulk-checkin.c
CommitLineData
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1/*
2 * Copyright (c) 2011, Google Inc.
3 */
1c4b6604 4#include "cache.h"
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5#include "bulk-checkin.h"
6#include "csum-file.h"
7#include "pack.h"
58892711 8#include "strbuf.h"
0abe14f6 9#include "packfile.h"
568508e7 10
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11static 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
24static void finish_bulk_checkin(struct bulk_checkin_state *state)
25{
fa33c3aa 26 struct object_id oid;
58892711 27 struct strbuf packname = STRBUF_INIT;
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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) {
fa33c3aa 38 sha1close(state->f, oid.hash, CSUM_FSYNC);
568508e7 39 } else {
fa33c3aa 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,
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43 state->offset);
44 close(fd);
45 }
46
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47 strbuf_addf(&packname, "%s/pack/pack-", get_object_directory());
48 finish_tmp_packfile(&packname, state->pack_tmp_name,
568508e7 49 state->written, state->nr_written,
fa33c3aa 50 &state->pack_idx_opts, oid.hash);
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51 for (i = 0; i < state->nr_written; i++)
52 free(state->written[i]);
53
54clear_exit:
55 free(state->written);
56 memset(state, 0, sizeof(*state));
57
58892711 58 strbuf_release(&packname);
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59 /* Make objects we just wrote available to ourselves */
60 reprepare_packed_git();
61}
62
63static 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++)
e6a492b7 73 if (!hashcmp(state->written[i]->oid.hash, sha1))
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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 */
95static 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
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107 git_deflate_init(&s, pack_compression_level);
108
7202a6fa 109 hdrlen = encode_in_pack_object_header(obuf, sizeof(obuf), type, size);
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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);
e92527c9 118 if (read_in_full(fd, ibuf, rsize) != rsize)
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119 die("failed to read %d bytes from '%s'",
120 (int)rsize, path);
121 offset += rsize;
122 if (*already_hashed_to < offset) {
123 size_t hsize = offset - *already_hashed_to;
124 if (rsize < hsize)
125 hsize = rsize;
126 if (hsize)
127 git_SHA1_Update(ctx, ibuf, hsize);
128 *already_hashed_to = offset;
129 }
130 s.next_in = ibuf;
131 s.avail_in = rsize;
132 size -= rsize;
133 }
134
135 status = git_deflate(&s, size ? 0 : Z_FINISH);
136
137 if (!s.avail_out || status == Z_STREAM_END) {
138 if (write_object) {
139 size_t written = s.next_out - obuf;
140
141 /* would we bust the size limit? */
142 if (state->nr_written &&
143 pack_size_limit_cfg &&
144 pack_size_limit_cfg < state->offset + written) {
145 git_deflate_abort(&s);
146 return -1;
147 }
148
149 sha1write(state->f, obuf, written);
150 state->offset += written;
151 }
152 s.next_out = obuf;
153 s.avail_out = sizeof(obuf);
154 }
155
156 switch (status) {
157 case Z_OK:
158 case Z_BUF_ERROR:
159 case Z_STREAM_END:
160 continue;
161 default:
162 die("unexpected deflate failure: %d", status);
163 }
164 }
165 git_deflate_end(&s);
166 return 0;
167}
168
169/* Lazily create backing packfile for the state */
170static void prepare_to_stream(struct bulk_checkin_state *state,
171 unsigned flags)
172{
173 if (!(flags & HASH_WRITE_OBJECT) || state->f)
174 return;
175
176 state->f = create_tmp_packfile(&state->pack_tmp_name);
177 reset_pack_idx_option(&state->pack_idx_opts);
178
179 /* Pretend we are going to write only one object */
180 state->offset = write_pack_header(state->f, 1);
181 if (!state->offset)
182 die_errno("unable to write pack header");
183}
184
185static int deflate_to_pack(struct bulk_checkin_state *state,
186 unsigned char result_sha1[],
187 int fd, size_t size,
188 enum object_type type, const char *path,
189 unsigned flags)
190{
191 off_t seekback, already_hashed_to;
192 git_SHA_CTX ctx;
193 unsigned char obuf[16384];
194 unsigned header_len;
195 struct sha1file_checkpoint checkpoint;
196 struct pack_idx_entry *idx = NULL;
197
198 seekback = lseek(fd, 0, SEEK_CUR);
199 if (seekback == (off_t) -1)
200 return error("cannot find the current offset");
201
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202 header_len = xsnprintf((char *)obuf, sizeof(obuf), "%s %" PRIuMAX,
203 typename(type), (uintmax_t)size) + 1;
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204 git_SHA1_Init(&ctx);
205 git_SHA1_Update(&ctx, obuf, header_len);
206
207 /* Note: idx is non-NULL when we are writing */
208 if ((flags & HASH_WRITE_OBJECT) != 0)
209 idx = xcalloc(1, sizeof(*idx));
210
211 already_hashed_to = 0;
212
213 while (1) {
214 prepare_to_stream(state, flags);
215 if (idx) {
216 sha1file_checkpoint(state->f, &checkpoint);
217 idx->offset = state->offset;
218 crc32_begin(state->f);
219 }
220 if (!stream_to_pack(state, &ctx, &already_hashed_to,
221 fd, size, type, path, flags))
222 break;
223 /*
224 * Writing this object to the current pack will make
225 * it too big; we need to truncate it, start a new
226 * pack, and write into it.
227 */
228 if (!idx)
229 die("BUG: should not happen");
230 sha1file_truncate(state->f, &checkpoint);
231 state->offset = checkpoint.offset;
232 finish_bulk_checkin(state);
233 if (lseek(fd, seekback, SEEK_SET) == (off_t) -1)
234 return error("cannot seek back");
235 }
236 git_SHA1_Final(result_sha1, &ctx);
237 if (!idx)
238 return 0;
239
240 idx->crc32 = crc32_end(state->f);
241 if (already_written(state, result_sha1)) {
242 sha1file_truncate(state->f, &checkpoint);
243 state->offset = checkpoint.offset;
244 free(idx);
245 } else {
e6a492b7 246 hashcpy(idx->oid.hash, result_sha1);
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247 ALLOC_GROW(state->written,
248 state->nr_written + 1,
249 state->alloc_written);
250 state->written[state->nr_written++] = idx;
251 }
252 return 0;
253}
254
255int index_bulk_checkin(unsigned char *sha1,
256 int fd, size_t size, enum object_type type,
257 const char *path, unsigned flags)
258{
259 int status = deflate_to_pack(&state, sha1, fd, size, type,
260 path, flags);
261 if (!state.plugged)
262 finish_bulk_checkin(&state);
263 return status;
264}
265
266void plug_bulk_checkin(void)
267{
268 state.plugged = 1;
269}
270
271void unplug_bulk_checkin(void)
272{
273 state.plugged = 0;
274 if (state.f)
275 finish_bulk_checkin(&state);
276}