Documentation/git-http-fetch.txt: Document the commit-id argument.
[git] / http-fetch.c
1 #include "cache.h"
2 #include "commit.h"
3 #include "pack.h"
4 #include "fetch.h"
5 #include "http.h"
6
7 #define PREV_BUF_SIZE 4096
8 #define RANGE_HEADER_SIZE 30
9
10 static int got_alternates = -1;
11
12 static struct curl_slist *no_pragma_header;
13
14 struct alt_base
15 {
16         char *base;
17         int got_indices;
18         struct packed_git *packs;
19         struct alt_base *next;
20 };
21
22 static struct alt_base *alt = NULL;
23
24 enum object_request_state {
25         WAITING,
26         ABORTED,
27         ACTIVE,
28         COMPLETE,
29 };
30
31 struct object_request
32 {
33         unsigned char sha1[20];
34         struct alt_base *repo;
35         char *url;
36         char filename[PATH_MAX];
37         char tmpfile[PATH_MAX];
38         int local;
39         enum object_request_state state;
40         CURLcode curl_result;
41         char errorstr[CURL_ERROR_SIZE];
42         long http_code;
43         unsigned char real_sha1[20];
44         SHA_CTX c;
45         z_stream stream;
46         int zret;
47         int rename;
48         struct active_request_slot *slot;
49         struct object_request *next;
50 };
51
52 struct alternates_request {
53         char *base;
54         char *url;
55         struct buffer *buffer;
56         struct active_request_slot *slot;
57         int http_specific;
58 };
59
60 static struct object_request *object_queue_head = NULL;
61
62 static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
63                                void *data)
64 {
65         unsigned char expn[4096];
66         size_t size = eltsize * nmemb;
67         int posn = 0;
68         struct object_request *obj_req = (struct object_request *)data;
69         do {
70                 ssize_t retval = write(obj_req->local,
71                                        ptr + posn, size - posn);
72                 if (retval < 0)
73                         return posn;
74                 posn += retval;
75         } while (posn < size);
76
77         obj_req->stream.avail_in = size;
78         obj_req->stream.next_in = ptr;
79         do {
80                 obj_req->stream.next_out = expn;
81                 obj_req->stream.avail_out = sizeof(expn);
82                 obj_req->zret = inflate(&obj_req->stream, Z_SYNC_FLUSH);
83                 SHA1_Update(&obj_req->c, expn,
84                             sizeof(expn) - obj_req->stream.avail_out);
85         } while (obj_req->stream.avail_in && obj_req->zret == Z_OK);
86         data_received++;
87         return size;
88 }
89
90 static void fetch_alternates(char *base);
91
92 static void process_object_response(void *callback_data);
93
94 static void start_object_request(struct object_request *obj_req)
95 {
96         char *hex = sha1_to_hex(obj_req->sha1);
97         char prevfile[PATH_MAX];
98         char *url;
99         char *posn;
100         int prevlocal;
101         unsigned char prev_buf[PREV_BUF_SIZE];
102         ssize_t prev_read = 0;
103         long prev_posn = 0;
104         char range[RANGE_HEADER_SIZE];
105         struct curl_slist *range_header = NULL;
106         struct active_request_slot *slot;
107
108         snprintf(prevfile, sizeof(prevfile), "%s.prev", obj_req->filename);
109         unlink(prevfile);
110         rename(obj_req->tmpfile, prevfile);
111         unlink(obj_req->tmpfile);
112
113         if (obj_req->local != -1)
114                 error("fd leakage in start: %d", obj_req->local);
115         obj_req->local = open(obj_req->tmpfile,
116                               O_WRONLY | O_CREAT | O_EXCL, 0666);
117         /* This could have failed due to the "lazy directory creation";
118          * try to mkdir the last path component.
119          */
120         if (obj_req->local < 0 && errno == ENOENT) {
121                 char *dir = strrchr(obj_req->tmpfile, '/');
122                 if (dir) {
123                         *dir = 0;
124                         mkdir(obj_req->tmpfile, 0777);
125                         *dir = '/';
126                 }
127                 obj_req->local = open(obj_req->tmpfile,
128                                       O_WRONLY | O_CREAT | O_EXCL, 0666);
129         }
130
131         if (obj_req->local < 0) {
132                 obj_req->state = ABORTED;
133                 error("Couldn't create temporary file %s for %s: %s\n",
134                       obj_req->tmpfile, obj_req->filename, strerror(errno));
135                 return;
136         }
137
138         memset(&obj_req->stream, 0, sizeof(obj_req->stream));
139
140         inflateInit(&obj_req->stream);
141
142         SHA1_Init(&obj_req->c);
143
144         url = xmalloc(strlen(obj_req->repo->base) + 50);
145         obj_req->url = xmalloc(strlen(obj_req->repo->base) + 50);
146         strcpy(url, obj_req->repo->base);
147         posn = url + strlen(obj_req->repo->base);
148         strcpy(posn, "objects/");
149         posn += 8;
150         memcpy(posn, hex, 2);
151         posn += 2;
152         *(posn++) = '/';
153         strcpy(posn, hex + 2);
154         strcpy(obj_req->url, url);
155
156         /* If a previous temp file is present, process what was already
157            fetched. */
158         prevlocal = open(prevfile, O_RDONLY);
159         if (prevlocal != -1) {
160                 do {
161                         prev_read = read(prevlocal, prev_buf, PREV_BUF_SIZE);
162                         if (prev_read>0) {
163                                 if (fwrite_sha1_file(prev_buf,
164                                                      1,
165                                                      prev_read,
166                                                      obj_req) == prev_read) {
167                                         prev_posn += prev_read;
168                                 } else {
169                                         prev_read = -1;
170                                 }
171                         }
172                 } while (prev_read > 0);
173                 close(prevlocal);
174         }
175         unlink(prevfile);
176
177         /* Reset inflate/SHA1 if there was an error reading the previous temp
178            file; also rewind to the beginning of the local file. */
179         if (prev_read == -1) {
180                 memset(&obj_req->stream, 0, sizeof(obj_req->stream));
181                 inflateInit(&obj_req->stream);
182                 SHA1_Init(&obj_req->c);
183                 if (prev_posn>0) {
184                         prev_posn = 0;
185                         lseek(obj_req->local, SEEK_SET, 0);
186                         ftruncate(obj_req->local, 0);
187                 }
188         }
189
190         slot = get_active_slot();
191         slot->callback_func = process_object_response;
192         slot->callback_data = obj_req;
193         obj_req->slot = slot;
194
195         curl_easy_setopt(slot->curl, CURLOPT_FILE, obj_req);
196         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
197         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, obj_req->errorstr);
198         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
199         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
200
201         /* If we have successfully processed data from a previous fetch
202            attempt, only fetch the data we don't already have. */
203         if (prev_posn>0) {
204                 if (get_verbosely)
205                         fprintf(stderr,
206                                 "Resuming fetch of object %s at byte %ld\n",
207                                 hex, prev_posn);
208                 sprintf(range, "Range: bytes=%ld-", prev_posn);
209                 range_header = curl_slist_append(range_header, range);
210                 curl_easy_setopt(slot->curl,
211                                  CURLOPT_HTTPHEADER, range_header);
212         }
213
214         /* Try to get the request started, abort the request on error */
215         obj_req->state = ACTIVE;
216         if (!start_active_slot(slot)) {
217                 obj_req->state = ABORTED;
218                 obj_req->slot = NULL;
219                 close(obj_req->local); obj_req->local = -1;
220                 free(obj_req->url);
221                 return;
222         }
223         
224 }
225
226 static void finish_object_request(struct object_request *obj_req)
227 {
228         struct stat st;
229
230         fchmod(obj_req->local, 0444);
231         close(obj_req->local); obj_req->local = -1;
232
233         if (obj_req->http_code == 416) {
234                 fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
235         } else if (obj_req->curl_result != CURLE_OK) {
236                 if (stat(obj_req->tmpfile, &st) == 0)
237                         if (st.st_size == 0)
238                                 unlink(obj_req->tmpfile);
239                 return;
240         }
241
242         inflateEnd(&obj_req->stream);
243         SHA1_Final(obj_req->real_sha1, &obj_req->c);
244         if (obj_req->zret != Z_STREAM_END) {
245                 unlink(obj_req->tmpfile);
246                 return;
247         }
248         if (memcmp(obj_req->sha1, obj_req->real_sha1, 20)) {
249                 unlink(obj_req->tmpfile);
250                 return;
251         }
252         obj_req->rename =
253                 move_temp_to_file(obj_req->tmpfile, obj_req->filename);
254
255         if (obj_req->rename == 0)
256                 pull_say("got %s\n", sha1_to_hex(obj_req->sha1));
257 }
258
259 static void process_object_response(void *callback_data)
260 {
261         struct object_request *obj_req =
262                 (struct object_request *)callback_data;
263
264         obj_req->curl_result = obj_req->slot->curl_result;
265         obj_req->http_code = obj_req->slot->http_code;
266         obj_req->slot = NULL;
267         obj_req->state = COMPLETE;
268
269         /* Use alternates if necessary */
270         if (obj_req->http_code == 404) {
271                 fetch_alternates(alt->base);
272                 if (obj_req->repo->next != NULL) {
273                         obj_req->repo =
274                                 obj_req->repo->next;
275                         close(obj_req->local);
276                         obj_req->local = -1;
277                         start_object_request(obj_req);
278                         return;
279                 }
280         }
281
282         finish_object_request(obj_req);
283 }
284
285 static void release_object_request(struct object_request *obj_req)
286 {
287         struct object_request *entry = object_queue_head;
288
289         if (obj_req->local != -1)
290                 error("fd leakage in release: %d", obj_req->local);
291         if (obj_req == object_queue_head) {
292                 object_queue_head = obj_req->next;
293         } else {
294                 while (entry->next != NULL && entry->next != obj_req)
295                         entry = entry->next;
296                 if (entry->next == obj_req)
297                         entry->next = entry->next->next;
298         }
299
300         free(obj_req->url);
301         free(obj_req);
302 }
303
304 #ifdef USE_CURL_MULTI
305 void fill_active_slots(void)
306 {
307         struct object_request *obj_req = object_queue_head;
308         struct active_request_slot *slot = active_queue_head;
309         int num_transfers;
310
311         while (active_requests < max_requests && obj_req != NULL) {
312                 if (obj_req->state == WAITING) {
313                         if (has_sha1_file(obj_req->sha1))
314                                 release_object_request(obj_req);
315                         else
316                                 start_object_request(obj_req);
317                         curl_multi_perform(curlm, &num_transfers);
318                 }
319                 obj_req = obj_req->next;
320         }
321
322         while (slot != NULL) {
323                 if (!slot->in_use && slot->curl != NULL) {
324                         curl_easy_cleanup(slot->curl);
325                         slot->curl = NULL;
326                 }
327                 slot = slot->next;
328         }                               
329 }
330 #endif
331
332 void prefetch(unsigned char *sha1)
333 {
334         struct object_request *newreq;
335         struct object_request *tail;
336         char *filename = sha1_file_name(sha1);
337
338         newreq = xmalloc(sizeof(*newreq));
339         memcpy(newreq->sha1, sha1, 20);
340         newreq->repo = alt;
341         newreq->url = NULL;
342         newreq->local = -1;
343         newreq->state = WAITING;
344         snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
345         snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
346                  "%s.temp", filename);
347         newreq->next = NULL;
348
349         if (object_queue_head == NULL) {
350                 object_queue_head = newreq;
351         } else {
352                 tail = object_queue_head;
353                 while (tail->next != NULL) {
354                         tail = tail->next;
355                 }
356                 tail->next = newreq;
357         }
358
359 #ifdef USE_CURL_MULTI
360         fill_active_slots();
361         step_active_slots();
362 #endif
363 }
364
365 static int fetch_index(struct alt_base *repo, unsigned char *sha1)
366 {
367         char *hex = sha1_to_hex(sha1);
368         char *filename;
369         char *url;
370         char tmpfile[PATH_MAX];
371         long prev_posn = 0;
372         char range[RANGE_HEADER_SIZE];
373         struct curl_slist *range_header = NULL;
374
375         FILE *indexfile;
376         struct active_request_slot *slot;
377
378         if (has_pack_index(sha1))
379                 return 0;
380
381         if (get_verbosely)
382                 fprintf(stderr, "Getting index for pack %s\n", hex);
383         
384         url = xmalloc(strlen(repo->base) + 64);
385         sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
386         
387         filename = sha1_pack_index_name(sha1);
388         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
389         indexfile = fopen(tmpfile, "a");
390         if (!indexfile)
391                 return error("Unable to open local file %s for pack index",
392                              filename);
393
394         slot = get_active_slot();
395         curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
396         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
397         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
398         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
399         slot->local = indexfile;
400
401         /* If there is data present from a previous transfer attempt,
402            resume where it left off */
403         prev_posn = ftell(indexfile);
404         if (prev_posn>0) {
405                 if (get_verbosely)
406                         fprintf(stderr,
407                                 "Resuming fetch of index for pack %s at byte %ld\n",
408                                 hex, prev_posn);
409                 sprintf(range, "Range: bytes=%ld-", prev_posn);
410                 range_header = curl_slist_append(range_header, range);
411                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
412         }
413
414         if (start_active_slot(slot)) {
415                 run_active_slot(slot);
416                 if (slot->curl_result != CURLE_OK) {
417                         fclose(indexfile);
418                         return error("Unable to get pack index %s\n%s", url,
419                                      curl_errorstr);
420                 }
421         } else {
422                 fclose(indexfile);
423                 return error("Unable to start request");
424         }
425
426         fclose(indexfile);
427
428         return move_temp_to_file(tmpfile, filename);
429 }
430
431 static int setup_index(struct alt_base *repo, unsigned char *sha1)
432 {
433         struct packed_git *new_pack;
434         if (has_pack_file(sha1))
435                 return 0; // don't list this as something we can get
436
437         if (fetch_index(repo, sha1))
438                 return -1;
439
440         new_pack = parse_pack_index(sha1);
441         new_pack->next = repo->packs;
442         repo->packs = new_pack;
443         return 0;
444 }
445
446 static void process_alternates_response(void *callback_data)
447 {
448         struct alternates_request *alt_req =
449                 (struct alternates_request *)callback_data;
450         struct active_request_slot *slot = alt_req->slot;
451         struct alt_base *tail = alt;
452         char *base = alt_req->base;
453         static const char null_byte = '\0';
454         char *data;
455         int i = 0;
456
457         if (alt_req->http_specific) {
458                 if (slot->curl_result != CURLE_OK ||
459                     !alt_req->buffer->posn) {
460
461                         /* Try reusing the slot to get non-http alternates */
462                         alt_req->http_specific = 0;
463                         sprintf(alt_req->url, "%s/objects/info/alternates",
464                                 base);
465                         curl_easy_setopt(slot->curl, CURLOPT_URL,
466                                          alt_req->url);
467                         active_requests++;
468                         slot->in_use = 1;
469                         if (start_active_slot(slot)) {
470                                 return;
471                         } else {
472                                 got_alternates = -1;
473                                 slot->in_use = 0;
474                                 return;
475                         }
476                 }
477         } else if (slot->curl_result != CURLE_OK) {
478                 if (slot->http_code != 404) {
479                         got_alternates = -1;
480                         return;
481                 }
482         }
483
484         fwrite_buffer(&null_byte, 1, 1, alt_req->buffer);
485         alt_req->buffer->posn--;
486         data = alt_req->buffer->buffer;
487
488         while (i < alt_req->buffer->posn) {
489                 int posn = i;
490                 while (posn < alt_req->buffer->posn && data[posn] != '\n')
491                         posn++;
492                 if (data[posn] == '\n') {
493                         int okay = 0;
494                         int serverlen = 0;
495                         struct alt_base *newalt;
496                         char *target = NULL;
497                         if (data[i] == '/') {
498                                 serverlen = strchr(base + 8, '/') - base;
499                                 okay = 1;
500                         } else if (!memcmp(data + i, "../", 3)) {
501                                 i += 3;
502                                 serverlen = strlen(base);
503                                 while (i + 2 < posn && 
504                                        !memcmp(data + i, "../", 3)) {
505                                         do {
506                                                 serverlen--;
507                                         } while (serverlen &&
508                                                  base[serverlen - 1] != '/');
509                                         i += 3;
510                                 }
511                                 // If the server got removed, give up.
512                                 okay = strchr(base, ':') - base + 3 < 
513                                         serverlen;
514                         } else if (alt_req->http_specific) {
515                                 char *colon = strchr(data + i, ':');
516                                 char *slash = strchr(data + i, '/');
517                                 if (colon && slash && colon < data + posn &&
518                                     slash < data + posn && colon < slash) {
519                                         okay = 1;
520                                 }
521                         }
522                         // skip 'objects' at end
523                         if (okay) {
524                                 target = xmalloc(serverlen + posn - i - 6);
525                                 strncpy(target, base, serverlen);
526                                 strncpy(target + serverlen, data + i,
527                                         posn - i - 7);
528                                 target[serverlen + posn - i - 7] = '\0';
529                                 if (get_verbosely)
530                                         fprintf(stderr, 
531                                                 "Also look at %s\n", target);
532                                 newalt = xmalloc(sizeof(*newalt));
533                                 newalt->next = NULL;
534                                 newalt->base = target;
535                                 newalt->got_indices = 0;
536                                 newalt->packs = NULL;
537                                 while (tail->next != NULL)
538                                         tail = tail->next;
539                                 tail->next = newalt;
540                         }
541                 }
542                 i = posn + 1;
543         }
544
545         got_alternates = 1;
546 }
547
548 static void fetch_alternates(char *base)
549 {
550         struct buffer buffer;
551         char *url;
552         char *data;
553         struct active_request_slot *slot;
554         static struct alternates_request alt_req;
555
556         /* If another request has already started fetching alternates,
557            wait for them to arrive and return to processing this request's
558            curl message */
559 #ifdef USE_CURL_MULTI
560         while (got_alternates == 0) {
561                 step_active_slots();
562         }
563 #endif
564
565         /* Nothing to do if they've already been fetched */
566         if (got_alternates == 1)
567                 return;
568
569         /* Start the fetch */
570         got_alternates = 0;
571
572         data = xmalloc(4096);
573         buffer.size = 4096;
574         buffer.posn = 0;
575         buffer.buffer = data;
576
577         if (get_verbosely)
578                 fprintf(stderr, "Getting alternates list for %s\n", base);
579         
580         url = xmalloc(strlen(base) + 31);
581         sprintf(url, "%s/objects/info/http-alternates", base);
582
583         /* Use a callback to process the result, since another request
584            may fail and need to have alternates loaded before continuing */
585         slot = get_active_slot();
586         slot->callback_func = process_alternates_response;
587         slot->callback_data = &alt_req;
588
589         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
590         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
591         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
592
593         alt_req.base = base;
594         alt_req.url = url;
595         alt_req.buffer = &buffer;
596         alt_req.http_specific = 1;
597         alt_req.slot = slot;
598
599         if (start_active_slot(slot))
600                 run_active_slot(slot);
601         else
602                 got_alternates = -1;
603
604         free(data);
605         free(url);
606 }
607
608 static int fetch_indices(struct alt_base *repo)
609 {
610         unsigned char sha1[20];
611         char *url;
612         struct buffer buffer;
613         char *data;
614         int i = 0;
615
616         struct active_request_slot *slot;
617
618         if (repo->got_indices)
619                 return 0;
620
621         data = xmalloc(4096);
622         buffer.size = 4096;
623         buffer.posn = 0;
624         buffer.buffer = data;
625
626         if (get_verbosely)
627                 fprintf(stderr, "Getting pack list for %s\n", repo->base);
628         
629         url = xmalloc(strlen(repo->base) + 21);
630         sprintf(url, "%s/objects/info/packs", repo->base);
631
632         slot = get_active_slot();
633         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
634         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
635         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
636         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
637         if (start_active_slot(slot)) {
638                 run_active_slot(slot);
639                 if (slot->curl_result != CURLE_OK) {
640                         if (slot->http_code == 404) {
641                                 repo->got_indices = 1;
642                                 free(buffer.buffer);
643                                 return 0;
644                         } else {
645                                 repo->got_indices = 0;
646                                 free(buffer.buffer);
647                                 return error("%s", curl_errorstr);
648                         }
649                 }
650         } else {
651                 repo->got_indices = 0;
652                 free(buffer.buffer);
653                 return error("Unable to start request");
654         }
655
656         data = buffer.buffer;
657         while (i < buffer.posn) {
658                 switch (data[i]) {
659                 case 'P':
660                         i++;
661                         if (i + 52 < buffer.posn &&
662                             !strncmp(data + i, " pack-", 6) &&
663                             !strncmp(data + i + 46, ".pack\n", 6)) {
664                                 get_sha1_hex(data + i + 6, sha1);
665                                 setup_index(repo, sha1);
666                                 i += 51;
667                                 break;
668                         }
669                 default:
670                         while (data[i] != '\n')
671                                 i++;
672                 }
673                 i++;
674         }
675
676         free(buffer.buffer);
677         repo->got_indices = 1;
678         return 0;
679 }
680
681 static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
682 {
683         char *url;
684         struct packed_git *target;
685         struct packed_git **lst;
686         FILE *packfile;
687         char *filename;
688         char tmpfile[PATH_MAX];
689         int ret;
690         long prev_posn = 0;
691         char range[RANGE_HEADER_SIZE];
692         struct curl_slist *range_header = NULL;
693
694         struct active_request_slot *slot;
695
696         if (fetch_indices(repo))
697                 return -1;
698         target = find_sha1_pack(sha1, repo->packs);
699         if (!target)
700                 return -1;
701
702         if (get_verbosely) {
703                 fprintf(stderr, "Getting pack %s\n",
704                         sha1_to_hex(target->sha1));
705                 fprintf(stderr, " which contains %s\n",
706                         sha1_to_hex(sha1));
707         }
708
709         url = xmalloc(strlen(repo->base) + 65);
710         sprintf(url, "%s/objects/pack/pack-%s.pack",
711                 repo->base, sha1_to_hex(target->sha1));
712
713         filename = sha1_pack_name(target->sha1);
714         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
715         packfile = fopen(tmpfile, "a");
716         if (!packfile)
717                 return error("Unable to open local file %s for pack",
718                              filename);
719
720         slot = get_active_slot();
721         curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
722         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
723         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
724         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
725         slot->local = packfile;
726
727         /* If there is data present from a previous transfer attempt,
728            resume where it left off */
729         prev_posn = ftell(packfile);
730         if (prev_posn>0) {
731                 if (get_verbosely)
732                         fprintf(stderr,
733                                 "Resuming fetch of pack %s at byte %ld\n",
734                                 sha1_to_hex(target->sha1), prev_posn);
735                 sprintf(range, "Range: bytes=%ld-", prev_posn);
736                 range_header = curl_slist_append(range_header, range);
737                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
738         }
739
740         if (start_active_slot(slot)) {
741                 run_active_slot(slot);
742                 if (slot->curl_result != CURLE_OK) {
743                         fclose(packfile);
744                         return error("Unable to get pack file %s\n%s", url,
745                                      curl_errorstr);
746                 }
747         } else {
748                 fclose(packfile);
749                 return error("Unable to start request");
750         }
751
752         fclose(packfile);
753
754         ret = move_temp_to_file(tmpfile, filename);
755         if (ret)
756                 return ret;
757
758         lst = &repo->packs;
759         while (*lst != target)
760                 lst = &((*lst)->next);
761         *lst = (*lst)->next;
762
763         if (verify_pack(target, 0))
764                 return -1;
765         install_packed_git(target);
766
767         return 0;
768 }
769
770 static int fetch_object(struct alt_base *repo, unsigned char *sha1)
771 {
772         char *hex = sha1_to_hex(sha1);
773         int ret = 0;
774         struct object_request *obj_req = object_queue_head;
775
776         while (obj_req != NULL && memcmp(obj_req->sha1, sha1, 20))
777                 obj_req = obj_req->next;
778         if (obj_req == NULL)
779                 return error("Couldn't find request for %s in the queue", hex);
780
781         if (has_sha1_file(obj_req->sha1)) {
782                 release_object_request(obj_req);
783                 return 0;
784         }
785
786 #ifdef USE_CURL_MULTI
787         while (obj_req->state == WAITING) {
788                 step_active_slots();
789         }
790 #else
791         start_object_request(obj_req);
792 #endif
793
794         while (obj_req->state == ACTIVE) {
795                 run_active_slot(obj_req->slot);
796         }
797         if (obj_req->local != -1) {
798                 close(obj_req->local); obj_req->local = -1;
799         }
800
801         if (obj_req->state == ABORTED) {
802                 ret = error("Request for %s aborted", hex);
803         } else if (obj_req->curl_result != CURLE_OK &&
804                    obj_req->http_code != 416) {
805                 if (obj_req->http_code == 404)
806                         ret = -1; /* Be silent, it is probably in a pack. */
807                 else
808                         ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
809                                     obj_req->errorstr, obj_req->curl_result,
810                                     obj_req->http_code, hex);
811         } else if (obj_req->zret != Z_STREAM_END) {
812                 ret = error("File %s (%s) corrupt\n", hex, obj_req->url);
813         } else if (memcmp(obj_req->sha1, obj_req->real_sha1, 20)) {
814                 ret = error("File %s has bad hash\n", hex);
815         } else if (obj_req->rename < 0) {
816                 ret = error("unable to write sha1 filename %s: %s",
817                             obj_req->filename,
818                             strerror(obj_req->rename));
819         }
820
821         release_object_request(obj_req);
822         return ret;
823 }
824
825 int fetch(unsigned char *sha1)
826 {
827         struct alt_base *altbase = alt;
828
829         if (!fetch_object(altbase, sha1))
830                 return 0;
831         while (altbase) {
832                 if (!fetch_pack(altbase, sha1))
833                         return 0;
834                 fetch_alternates(alt->base);
835                 altbase = altbase->next;
836         }
837         return error("Unable to find %s under %s\n", sha1_to_hex(sha1), 
838                      alt->base);
839 }
840
841 static inline int needs_quote(int ch)
842 {
843         switch (ch) {
844         case '/': case '-': case '.':
845         case 'A'...'Z': case 'a'...'z': case '0'...'9':
846                 return 0;
847         default:
848                 return 1;
849         }
850 }
851
852 static inline int hex(int v)
853 {
854         if (v < 10) return '0' + v;
855         else return 'A' + v - 10;
856 }
857
858 static char *quote_ref_url(const char *base, const char *ref)
859 {
860         const char *cp;
861         char *dp, *qref;
862         int len, baselen, ch;
863
864         baselen = strlen(base);
865         len = baselen + 6; /* "refs/" + NUL */
866         for (cp = ref; (ch = *cp) != 0; cp++, len++)
867                 if (needs_quote(ch))
868                         len += 2; /* extra two hex plus replacement % */
869         qref = xmalloc(len);
870         memcpy(qref, base, baselen);
871         memcpy(qref + baselen, "refs/", 5);
872         for (cp = ref, dp = qref + baselen + 5; (ch = *cp) != 0; cp++) {
873                 if (needs_quote(ch)) {
874                         *dp++ = '%';
875                         *dp++ = hex((ch >> 4) & 0xF);
876                         *dp++ = hex(ch & 0xF);
877                 }
878                 else
879                         *dp++ = ch;
880         }
881         *dp = 0;
882
883         return qref;
884 }
885
886 int fetch_ref(char *ref, unsigned char *sha1)
887 {
888         char *url;
889         char hex[42];
890         struct buffer buffer;
891         char *base = alt->base;
892         struct active_request_slot *slot;
893         buffer.size = 41;
894         buffer.posn = 0;
895         buffer.buffer = hex;
896         hex[41] = '\0';
897         
898         url = quote_ref_url(base, ref);
899         slot = get_active_slot();
900         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
901         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
902         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
903         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
904         if (start_active_slot(slot)) {
905                 run_active_slot(slot);
906                 if (slot->curl_result != CURLE_OK)
907                         return error("Couldn't get %s for %s\n%s",
908                                      url, ref, curl_errorstr);
909         } else {
910                 return error("Unable to start request");
911         }
912
913         hex[40] = '\0';
914         get_sha1_hex(hex, sha1);
915         return 0;
916 }
917
918 int main(int argc, char **argv)
919 {
920         char *commit_id;
921         char *url;
922         int arg = 1;
923         int rc = 0;
924
925         setup_git_directory();
926
927         while (arg < argc && argv[arg][0] == '-') {
928                 if (argv[arg][1] == 't') {
929                         get_tree = 1;
930                 } else if (argv[arg][1] == 'c') {
931                         get_history = 1;
932                 } else if (argv[arg][1] == 'a') {
933                         get_all = 1;
934                         get_tree = 1;
935                         get_history = 1;
936                 } else if (argv[arg][1] == 'v') {
937                         get_verbosely = 1;
938                 } else if (argv[arg][1] == 'w') {
939                         write_ref = argv[arg + 1];
940                         arg++;
941                 } else if (!strcmp(argv[arg], "--recover")) {
942                         get_recover = 1;
943                 }
944                 arg++;
945         }
946         if (argc < arg + 2) {
947                 usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
948                 return 1;
949         }
950         commit_id = argv[arg];
951         url = argv[arg + 1];
952
953         http_init();
954
955         no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
956
957         alt = xmalloc(sizeof(*alt));
958         alt->base = url;
959         alt->got_indices = 0;
960         alt->packs = NULL;
961         alt->next = NULL;
962
963         if (pull(commit_id))
964                 rc = 1;
965
966         curl_slist_free_all(no_pragma_header);
967
968         http_cleanup();
969
970         return rc;
971 }