Re-implement 'git remote update' using 'git fetch'
[gitweb.git] / http-fetch.c
index 202fae0ba8b348aeca6ec6c61045f39aa0d1fa66..e8f44babd9d3a1cd86eba659b054aed6ac2c792a 100644 (file)
 #include "cache.h"
-#include "commit.h"
-#include "pack.h"
-#include "fetch.h"
-#include "http.h"
-
-#define PREV_BUF_SIZE 4096
-#define RANGE_HEADER_SIZE 30
-
-static int commits_on_stdin;
-
-static int got_alternates = -1;
-static int corrupt_object_found;
-
-static struct curl_slist *no_pragma_header;
-
-struct alt_base
-{
-       char *base;
-       int got_indices;
-       struct packed_git *packs;
-       struct alt_base *next;
-};
-
-static struct alt_base *alt;
-
-enum object_request_state {
-       WAITING,
-       ABORTED,
-       ACTIVE,
-       COMPLETE,
-};
-
-struct object_request
-{
-       unsigned char sha1[20];
-       struct alt_base *repo;
-       char *url;
-       char filename[PATH_MAX];
-       char tmpfile[PATH_MAX];
-       int local;
-       enum object_request_state state;
-       CURLcode curl_result;
-       char errorstr[CURL_ERROR_SIZE];
-       long http_code;
-       unsigned char real_sha1[20];
-       SHA_CTX c;
-       z_stream stream;
-       int zret;
-       int rename;
-       struct active_request_slot *slot;
-       struct object_request *next;
-};
-
-struct alternates_request {
-       const char *base;
-       char *url;
-       struct buffer *buffer;
-       struct active_request_slot *slot;
-       int http_specific;
-};
-
-static struct object_request *object_queue_head;
-
-static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
-                              void *data)
-{
-       unsigned char expn[4096];
-       size_t size = eltsize * nmemb;
-       int posn = 0;
-       struct object_request *obj_req = (struct object_request *)data;
-       do {
-               ssize_t retval = xwrite(obj_req->local,
-                                      (char *) ptr + posn, size - posn);
-               if (retval < 0)
-                       return posn;
-               posn += retval;
-       } while (posn < size);
-
-       obj_req->stream.avail_in = size;
-       obj_req->stream.next_in = ptr;
-       do {
-               obj_req->stream.next_out = expn;
-               obj_req->stream.avail_out = sizeof(expn);
-               obj_req->zret = inflate(&obj_req->stream, Z_SYNC_FLUSH);
-               SHA1_Update(&obj_req->c, expn,
-                           sizeof(expn) - obj_req->stream.avail_out);
-       } while (obj_req->stream.avail_in && obj_req->zret == Z_OK);
-       data_received++;
-       return size;
-}
-
-static int missing__target(int code, int result)
-{
-       return  /* file:// URL -- do we ever use one??? */
-               (result == CURLE_FILE_COULDNT_READ_FILE) ||
-               /* http:// and https:// URL */
-               (code == 404 && result == CURLE_HTTP_RETURNED_ERROR) ||
-               /* ftp:// URL */
-               (code == 550 && result == CURLE_FTP_COULDNT_RETR_FILE)
-               ;
-}
-
-#define missing_target(a) missing__target((a)->http_code, (a)->curl_result)
-
-static void fetch_alternates(const char *base);
-
-static void process_object_response(void *callback_data);
-
-static void start_object_request(struct object_request *obj_req)
-{
-       char *hex = sha1_to_hex(obj_req->sha1);
-       char prevfile[PATH_MAX];
-       char *url;
-       char *posn;
-       int prevlocal;
-       unsigned char prev_buf[PREV_BUF_SIZE];
-       ssize_t prev_read = 0;
-       long prev_posn = 0;
-       char range[RANGE_HEADER_SIZE];
-       struct curl_slist *range_header = NULL;
-       struct active_request_slot *slot;
-
-       snprintf(prevfile, sizeof(prevfile), "%s.prev", obj_req->filename);
-       unlink(prevfile);
-       rename(obj_req->tmpfile, prevfile);
-       unlink(obj_req->tmpfile);
-
-       if (obj_req->local != -1)
-               error("fd leakage in start: %d", obj_req->local);
-       obj_req->local = open(obj_req->tmpfile,
-                             O_WRONLY | O_CREAT | O_EXCL, 0666);
-       /* This could have failed due to the "lazy directory creation";
-        * try to mkdir the last path component.
-        */
-       if (obj_req->local < 0 && errno == ENOENT) {
-               char *dir = strrchr(obj_req->tmpfile, '/');
-               if (dir) {
-                       *dir = 0;
-                       mkdir(obj_req->tmpfile, 0777);
-                       *dir = '/';
-               }
-               obj_req->local = open(obj_req->tmpfile,
-                                     O_WRONLY | O_CREAT | O_EXCL, 0666);
-       }
-
-       if (obj_req->local < 0) {
-               obj_req->state = ABORTED;
-               error("Couldn't create temporary file %s for %s: %s",
-                     obj_req->tmpfile, obj_req->filename, strerror(errno));
-               return;
-       }
-
-       memset(&obj_req->stream, 0, sizeof(obj_req->stream));
-
-       inflateInit(&obj_req->stream);
-
-       SHA1_Init(&obj_req->c);
-
-       url = xmalloc(strlen(obj_req->repo->base) + 51);
-       obj_req->url = xmalloc(strlen(obj_req->repo->base) + 51);
-       strcpy(url, obj_req->repo->base);
-       posn = url + strlen(obj_req->repo->base);
-       strcpy(posn, "/objects/");
-       posn += 9;
-       memcpy(posn, hex, 2);
-       posn += 2;
-       *(posn++) = '/';
-       strcpy(posn, hex + 2);
-       strcpy(obj_req->url, url);
-
-       /* If a previous temp file is present, process what was already
-          fetched. */
-       prevlocal = open(prevfile, O_RDONLY);
-       if (prevlocal != -1) {
-               do {
-                       prev_read = xread(prevlocal, prev_buf, PREV_BUF_SIZE);
-                       if (prev_read>0) {
-                               if (fwrite_sha1_file(prev_buf,
-                                                    1,
-                                                    prev_read,
-                                                    obj_req) == prev_read) {
-                                       prev_posn += prev_read;
-                               } else {
-                                       prev_read = -1;
-                               }
-                       }
-               } while (prev_read > 0);
-               close(prevlocal);
-       }
-       unlink(prevfile);
-
-       /* Reset inflate/SHA1 if there was an error reading the previous temp
-          file; also rewind to the beginning of the local file. */
-       if (prev_read == -1) {
-               memset(&obj_req->stream, 0, sizeof(obj_req->stream));
-               inflateInit(&obj_req->stream);
-               SHA1_Init(&obj_req->c);
-               if (prev_posn>0) {
-                       prev_posn = 0;
-                       lseek(obj_req->local, 0, SEEK_SET);
-                       ftruncate(obj_req->local, 0);
-               }
-       }
-
-       slot = get_active_slot();
-       slot->callback_func = process_object_response;
-       slot->callback_data = obj_req;
-       obj_req->slot = slot;
-
-       curl_easy_setopt(slot->curl, CURLOPT_FILE, obj_req);
-       curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
-       curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, obj_req->errorstr);
-       curl_easy_setopt(slot->curl, CURLOPT_URL, url);
-       curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
-
-       /* If we have successfully processed data from a previous fetch
-          attempt, only fetch the data we don't already have. */
-       if (prev_posn>0) {
-               if (get_verbosely)
-                       fprintf(stderr,
-                               "Resuming fetch of object %s at byte %ld\n",
-                               hex, prev_posn);
-               sprintf(range, "Range: bytes=%ld-", prev_posn);
-               range_header = curl_slist_append(range_header, range);
-               curl_easy_setopt(slot->curl,
-                                CURLOPT_HTTPHEADER, range_header);
-       }
-
-       /* Try to get the request started, abort the request on error */
-       obj_req->state = ACTIVE;
-       if (!start_active_slot(slot)) {
-               obj_req->state = ABORTED;
-               obj_req->slot = NULL;
-               close(obj_req->local); obj_req->local = -1;
-               free(obj_req->url);
-               return;
-       }
-}
-
-static void finish_object_request(struct object_request *obj_req)
-{
-       struct stat st;
-
-       fchmod(obj_req->local, 0444);
-       close(obj_req->local); obj_req->local = -1;
-
-       if (obj_req->http_code == 416) {
-               fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
-       } else if (obj_req->curl_result != CURLE_OK) {
-               if (stat(obj_req->tmpfile, &st) == 0)
-                       if (st.st_size == 0)
-                               unlink(obj_req->tmpfile);
-               return;
-       }
-
-       inflateEnd(&obj_req->stream);
-       SHA1_Final(obj_req->real_sha1, &obj_req->c);
-       if (obj_req->zret != Z_STREAM_END) {
-               unlink(obj_req->tmpfile);
-               return;
-       }
-       if (hashcmp(obj_req->sha1, obj_req->real_sha1)) {
-               unlink(obj_req->tmpfile);
-               return;
-       }
-       obj_req->rename =
-               move_temp_to_file(obj_req->tmpfile, obj_req->filename);
-
-       if (obj_req->rename == 0)
-               pull_say("got %s\n", sha1_to_hex(obj_req->sha1));
-}
-
-static void process_object_response(void *callback_data)
-{
-       struct object_request *obj_req =
-               (struct object_request *)callback_data;
-
-       obj_req->curl_result = obj_req->slot->curl_result;
-       obj_req->http_code = obj_req->slot->http_code;
-       obj_req->slot = NULL;
-       obj_req->state = COMPLETE;
-
-       /* Use alternates if necessary */
-       if (missing_target(obj_req)) {
-               fetch_alternates(alt->base);
-               if (obj_req->repo->next != NULL) {
-                       obj_req->repo =
-                               obj_req->repo->next;
-                       close(obj_req->local);
-                       obj_req->local = -1;
-                       start_object_request(obj_req);
-                       return;
-               }
-       }
-
-       finish_object_request(obj_req);
-}
-
-static void release_object_request(struct object_request *obj_req)
-{
-       struct object_request *entry = object_queue_head;
-
-       if (obj_req->local != -1)
-               error("fd leakage in release: %d", obj_req->local);
-       if (obj_req == object_queue_head) {
-               object_queue_head = obj_req->next;
-       } else {
-               while (entry->next != NULL && entry->next != obj_req)
-                       entry = entry->next;
-               if (entry->next == obj_req)
-                       entry->next = entry->next->next;
-       }
-
-       free(obj_req->url);
-       free(obj_req);
-}
-
-#ifdef USE_CURL_MULTI
-void fill_active_slots(void)
-{
-       struct object_request *obj_req = object_queue_head;
-       struct active_request_slot *slot = active_queue_head;
-       int num_transfers;
-
-       while (active_requests < max_requests && obj_req != NULL) {
-               if (obj_req->state == WAITING) {
-                       if (has_sha1_file(obj_req->sha1))
-                               obj_req->state = COMPLETE;
-                       else
-                               start_object_request(obj_req);
-                       curl_multi_perform(curlm, &num_transfers);
-               }
-               obj_req = obj_req->next;
-       }
-
-       while (slot != NULL) {
-               if (!slot->in_use && slot->curl != NULL) {
-                       curl_easy_cleanup(slot->curl);
-                       slot->curl = NULL;
-               }
-               slot = slot->next;
-       }
-}
-#endif
-
-void prefetch(unsigned char *sha1)
-{
-       struct object_request *newreq;
-       struct object_request *tail;
-       char *filename = sha1_file_name(sha1);
-
-       newreq = xmalloc(sizeof(*newreq));
-       hashcpy(newreq->sha1, sha1);
-       newreq->repo = alt;
-       newreq->url = NULL;
-       newreq->local = -1;
-       newreq->state = WAITING;
-       snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
-       snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
-                "%s.temp", filename);
-       newreq->slot = NULL;
-       newreq->next = NULL;
-
-       if (object_queue_head == NULL) {
-               object_queue_head = newreq;
-       } else {
-               tail = object_queue_head;
-               while (tail->next != NULL) {
-                       tail = tail->next;
-               }
-               tail->next = newreq;
-       }
-
-#ifdef USE_CURL_MULTI
-       fill_active_slots();
-       step_active_slots();
-#endif
-}
-
-static int fetch_index(struct alt_base *repo, unsigned char *sha1)
-{
-       char *hex = sha1_to_hex(sha1);
-       char *filename;
-       char *url;
-       char tmpfile[PATH_MAX];
-       long prev_posn = 0;
-       char range[RANGE_HEADER_SIZE];
-       struct curl_slist *range_header = NULL;
-
-       FILE *indexfile;
-       struct active_request_slot *slot;
-       struct slot_results results;
-
-       if (has_pack_index(sha1))
-               return 0;
-
-       if (get_verbosely)
-               fprintf(stderr, "Getting index for pack %s\n", hex);
-
-       url = xmalloc(strlen(repo->base) + 64);
-       sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
-
-       filename = sha1_pack_index_name(sha1);
-       snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
-       indexfile = fopen(tmpfile, "a");
-       if (!indexfile)
-               return error("Unable to open local file %s for pack index",
-                            filename);
-
-       slot = get_active_slot();
-       slot->results = &results;
-       curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
-       curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
-       curl_easy_setopt(slot->curl, CURLOPT_URL, url);
-       curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
-       slot->local = indexfile;
-
-       /* If there is data present from a previous transfer attempt,
-          resume where it left off */
-       prev_posn = ftell(indexfile);
-       if (prev_posn>0) {
-               if (get_verbosely)
-                       fprintf(stderr,
-                               "Resuming fetch of index for pack %s at byte %ld\n",
-                               hex, prev_posn);
-               sprintf(range, "Range: bytes=%ld-", prev_posn);
-               range_header = curl_slist_append(range_header, range);
-               curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
-       }
-
-       if (start_active_slot(slot)) {
-               run_active_slot(slot);
-               if (results.curl_result != CURLE_OK) {
-                       fclose(indexfile);
-                       return error("Unable to get pack index %s\n%s", url,
-                                    curl_errorstr);
-               }
-       } else {
-               fclose(indexfile);
-               return error("Unable to start request");
-       }
-
-       fclose(indexfile);
-
-       return move_temp_to_file(tmpfile, filename);
-}
-
-static int setup_index(struct alt_base *repo, unsigned char *sha1)
-{
-       struct packed_git *new_pack;
-       if (has_pack_file(sha1))
-               return 0; /* don't list this as something we can get */
-
-       if (fetch_index(repo, sha1))
-               return -1;
-
-       new_pack = parse_pack_index(sha1);
-       new_pack->next = repo->packs;
-       repo->packs = new_pack;
-       return 0;
-}
-
-static void process_alternates_response(void *callback_data)
-{
-       struct alternates_request *alt_req =
-               (struct alternates_request *)callback_data;
-       struct active_request_slot *slot = alt_req->slot;
-       struct alt_base *tail = alt;
-       const char *base = alt_req->base;
-       static const char null_byte = '\0';
-       char *data;
-       int i = 0;
-
-       if (alt_req->http_specific) {
-               if (slot->curl_result != CURLE_OK ||
-                   !alt_req->buffer->posn) {
-
-                       /* Try reusing the slot to get non-http alternates */
-                       alt_req->http_specific = 0;
-                       sprintf(alt_req->url, "%s/objects/info/alternates",
-                               base);
-                       curl_easy_setopt(slot->curl, CURLOPT_URL,
-                                        alt_req->url);
-                       active_requests++;
-                       slot->in_use = 1;
-                       if (slot->finished != NULL)
-                               (*slot->finished) = 0;
-                       if (!start_active_slot(slot)) {
-                               got_alternates = -1;
-                               slot->in_use = 0;
-                               if (slot->finished != NULL)
-                                       (*slot->finished) = 1;
-                       }
-                       return;
-               }
-       } else if (slot->curl_result != CURLE_OK) {
-               if (!missing_target(slot)) {
-                       got_alternates = -1;
-                       return;
-               }
-       }
-
-       fwrite_buffer(&null_byte, 1, 1, alt_req->buffer);
-       alt_req->buffer->posn--;
-       data = alt_req->buffer->buffer;
-
-       while (i < alt_req->buffer->posn) {
-               int posn = i;
-               while (posn < alt_req->buffer->posn && data[posn] != '\n')
-                       posn++;
-               if (data[posn] == '\n') {
-                       int okay = 0;
-                       int serverlen = 0;
-                       struct alt_base *newalt;
-                       char *target = NULL;
-                       if (data[i] == '/') {
-                               /* This counts
-                                * http://git.host/pub/scm/linux.git/
-                                * -----------here^
-                                * so memcpy(dst, base, serverlen) will
-                                * copy up to "...git.host".
-                                */
-                               const char *colon_ss = strstr(base,"://");
-                               if (colon_ss) {
-                                       serverlen = (strchr(colon_ss + 3, '/')
-                                                    - base);
-                                       okay = 1;
-                               }
-                       } else if (!memcmp(data + i, "../", 3)) {
-                               /* Relative URL; chop the corresponding
-                                * number of subpath from base (and ../
-                                * from data), and concatenate the result.
-                                *
-                                * The code first drops ../ from data, and
-                                * then drops one ../ from data and one path
-                                * from base.  IOW, one extra ../ is dropped
-                                * from data than path is dropped from base.
-                                *
-                                * This is not wrong.  The alternate in
-                                *     http://git.host/pub/scm/linux.git/
-                                * to borrow from
-                                *     http://git.host/pub/scm/linus.git/
-                                * is ../../linus.git/objects/.  You need
-                                * two ../../ to borrow from your direct
-                                * neighbour.
-                                */
-                               i += 3;
-                               serverlen = strlen(base);
-                               while (i + 2 < posn &&
-                                      !memcmp(data + i, "../", 3)) {
-                                       do {
-                                               serverlen--;
-                                       } while (serverlen &&
-                                                base[serverlen - 1] != '/');
-                                       i += 3;
-                               }
-                               /* If the server got removed, give up. */
-                               okay = strchr(base, ':') - base + 3 <
-                                       serverlen;
-                       } else if (alt_req->http_specific) {
-                               char *colon = strchr(data + i, ':');
-                               char *slash = strchr(data + i, '/');
-                               if (colon && slash && colon < data + posn &&
-                                   slash < data + posn && colon < slash) {
-                                       okay = 1;
-                               }
-                       }
-                       /* skip "objects\n" at end */
-                       if (okay) {
-                               target = xmalloc(serverlen + posn - i - 6);
-                               memcpy(target, base, serverlen);
-                               memcpy(target + serverlen, data + i,
-                                      posn - i - 7);
-                               target[serverlen + posn - i - 7] = 0;
-                               if (get_verbosely)
-                                       fprintf(stderr,
-                                               "Also look at %s\n", target);
-                               newalt = xmalloc(sizeof(*newalt));
-                               newalt->next = NULL;
-                               newalt->base = target;
-                               newalt->got_indices = 0;
-                               newalt->packs = NULL;
-
-                               while (tail->next != NULL)
-                                       tail = tail->next;
-                               tail->next = newalt;
-                       }
-               }
-               i = posn + 1;
-       }
-
-       got_alternates = 1;
-}
-
-static void fetch_alternates(const char *base)
-{
-       struct buffer buffer;
-       char *url;
-       char *data;
-       struct active_request_slot *slot;
-       struct alternates_request alt_req;
-
-       /* If another request has already started fetching alternates,
-          wait for them to arrive and return to processing this request's
-          curl message */
-#ifdef USE_CURL_MULTI
-       while (got_alternates == 0) {
-               step_active_slots();
-       }
-#endif
-
-       /* Nothing to do if they've already been fetched */
-       if (got_alternates == 1)
-               return;
-
-       /* Start the fetch */
-       got_alternates = 0;
-
-       data = xmalloc(4096);
-       buffer.size = 4096;
-       buffer.posn = 0;
-       buffer.buffer = data;
-
-       if (get_verbosely)
-               fprintf(stderr, "Getting alternates list for %s\n", base);
-
-       url = xmalloc(strlen(base) + 31);
-       sprintf(url, "%s/objects/info/http-alternates", base);
-
-       /* Use a callback to process the result, since another request
-          may fail and need to have alternates loaded before continuing */
-       slot = get_active_slot();
-       slot->callback_func = process_alternates_response;
-       slot->callback_data = &alt_req;
-
-       curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
-       curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
-       curl_easy_setopt(slot->curl, CURLOPT_URL, url);
-
-       alt_req.base = base;
-       alt_req.url = url;
-       alt_req.buffer = &buffer;
-       alt_req.http_specific = 1;
-       alt_req.slot = slot;
-
-       if (start_active_slot(slot))
-               run_active_slot(slot);
-       else
-               got_alternates = -1;
-
-       free(data);
-       free(url);
-}
-
-static int fetch_indices(struct alt_base *repo)
-{
-       unsigned char sha1[20];
-       char *url;
-       struct buffer buffer;
-       char *data;
-       int i = 0;
-
-       struct active_request_slot *slot;
-       struct slot_results results;
-
-       if (repo->got_indices)
-               return 0;
-
-       data = xmalloc(4096);
-       buffer.size = 4096;
-       buffer.posn = 0;
-       buffer.buffer = data;
-
-       if (get_verbosely)
-               fprintf(stderr, "Getting pack list for %s\n", repo->base);
-
-       url = xmalloc(strlen(repo->base) + 21);
-       sprintf(url, "%s/objects/info/packs", repo->base);
-
-       slot = get_active_slot();
-       slot->results = &results;
-       curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
-       curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
-       curl_easy_setopt(slot->curl, CURLOPT_URL, url);
-       curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
-       if (start_active_slot(slot)) {
-               run_active_slot(slot);
-               if (results.curl_result != CURLE_OK) {
-                       if (missing_target(&results)) {
-                               repo->got_indices = 1;
-                               free(buffer.buffer);
-                               return 0;
-                       } else {
-                               repo->got_indices = 0;
-                               free(buffer.buffer);
-                               return error("%s", curl_errorstr);
-                       }
-               }
-       } else {
-               repo->got_indices = 0;
-               free(buffer.buffer);
-               return error("Unable to start request");
-       }
-
-       data = buffer.buffer;
-       while (i < buffer.posn) {
-               switch (data[i]) {
-               case 'P':
-                       i++;
-                       if (i + 52 <= buffer.posn &&
-                           !prefixcmp(data + i, " pack-") &&
-                           !prefixcmp(data + i + 46, ".pack\n")) {
-                               get_sha1_hex(data + i + 6, sha1);
-                               setup_index(repo, sha1);
-                               i += 51;
-                               break;
-                       }
-               default:
-                       while (i < buffer.posn && data[i] != '\n')
-                               i++;
-               }
-               i++;
-       }
-
-       free(buffer.buffer);
-       repo->got_indices = 1;
-       return 0;
-}
-
-static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
-{
-       char *url;
-       struct packed_git *target;
-       struct packed_git **lst;
-       FILE *packfile;
-       char *filename;
-       char tmpfile[PATH_MAX];
-       int ret;
-       long prev_posn = 0;
-       char range[RANGE_HEADER_SIZE];
-       struct curl_slist *range_header = NULL;
-
-       struct active_request_slot *slot;
-       struct slot_results results;
-
-       if (fetch_indices(repo))
-               return -1;
-       target = find_sha1_pack(sha1, repo->packs);
-       if (!target)
-               return -1;
-
-       if (get_verbosely) {
-               fprintf(stderr, "Getting pack %s\n",
-                       sha1_to_hex(target->sha1));
-               fprintf(stderr, " which contains %s\n",
-                       sha1_to_hex(sha1));
-       }
-
-       url = xmalloc(strlen(repo->base) + 65);
-       sprintf(url, "%s/objects/pack/pack-%s.pack",
-               repo->base, sha1_to_hex(target->sha1));
-
-       filename = sha1_pack_name(target->sha1);
-       snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
-       packfile = fopen(tmpfile, "a");
-       if (!packfile)
-               return error("Unable to open local file %s for pack",
-                            filename);
-
-       slot = get_active_slot();
-       slot->results = &results;
-       curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
-       curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
-       curl_easy_setopt(slot->curl, CURLOPT_URL, url);
-       curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
-       slot->local = packfile;
-
-       /* If there is data present from a previous transfer attempt,
-          resume where it left off */
-       prev_posn = ftell(packfile);
-       if (prev_posn>0) {
-               if (get_verbosely)
-                       fprintf(stderr,
-                               "Resuming fetch of pack %s at byte %ld\n",
-                               sha1_to_hex(target->sha1), prev_posn);
-               sprintf(range, "Range: bytes=%ld-", prev_posn);
-               range_header = curl_slist_append(range_header, range);
-               curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
-       }
-
-       if (start_active_slot(slot)) {
-               run_active_slot(slot);
-               if (results.curl_result != CURLE_OK) {
-                       fclose(packfile);
-                       return error("Unable to get pack file %s\n%s", url,
-                                    curl_errorstr);
-               }
-       } else {
-               fclose(packfile);
-               return error("Unable to start request");
-       }
-
-       target->pack_size = ftell(packfile);
-       fclose(packfile);
-
-       ret = move_temp_to_file(tmpfile, filename);
-       if (ret)
-               return ret;
-
-       lst = &repo->packs;
-       while (*lst != target)
-               lst = &((*lst)->next);
-       *lst = (*lst)->next;
-
-       if (verify_pack(target, 0))
-               return -1;
-       install_packed_git(target);
-
-       return 0;
-}
-
-static void abort_object_request(struct object_request *obj_req)
-{
-       if (obj_req->local >= 0) {
-               close(obj_req->local);
-               obj_req->local = -1;
-       }
-       unlink(obj_req->tmpfile);
-       if (obj_req->slot) {
-               release_active_slot(obj_req->slot);
-               obj_req->slot = NULL;
-       }
-       release_object_request(obj_req);
-}
-
-static int fetch_object(struct alt_base *repo, unsigned char *sha1)
-{
-       char *hex = sha1_to_hex(sha1);
-       int ret = 0;
-       struct object_request *obj_req = object_queue_head;
-
-       while (obj_req != NULL && hashcmp(obj_req->sha1, sha1))
-               obj_req = obj_req->next;
-       if (obj_req == NULL)
-               return error("Couldn't find request for %s in the queue", hex);
-
-       if (has_sha1_file(obj_req->sha1)) {
-               abort_object_request(obj_req);
-               return 0;
-       }
-
-#ifdef USE_CURL_MULTI
-       while (obj_req->state == WAITING) {
-               step_active_slots();
-       }
-#else
-       start_object_request(obj_req);
-#endif
-
-       while (obj_req->state == ACTIVE) {
-               run_active_slot(obj_req->slot);
-       }
-       if (obj_req->local != -1) {
-               close(obj_req->local); obj_req->local = -1;
-       }
-
-       if (obj_req->state == ABORTED) {
-               ret = error("Request for %s aborted", hex);
-       } else if (obj_req->curl_result != CURLE_OK &&
-                  obj_req->http_code != 416) {
-               if (missing_target(obj_req))
-                       ret = -1; /* Be silent, it is probably in a pack. */
-               else
-                       ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
-                                   obj_req->errorstr, obj_req->curl_result,
-                                   obj_req->http_code, hex);
-       } else if (obj_req->zret != Z_STREAM_END) {
-               corrupt_object_found++;
-               ret = error("File %s (%s) corrupt", hex, obj_req->url);
-       } else if (hashcmp(obj_req->sha1, obj_req->real_sha1)) {
-               ret = error("File %s has bad hash", hex);
-       } else if (obj_req->rename < 0) {
-               ret = error("unable to write sha1 filename %s",
-                           obj_req->filename);
-       }
-
-       release_object_request(obj_req);
-       return ret;
-}
-
-int fetch(unsigned char *sha1)
-{
-       struct alt_base *altbase = alt;
-
-       if (!fetch_object(altbase, sha1))
-               return 0;
-       while (altbase) {
-               if (!fetch_pack(altbase, sha1))
-                       return 0;
-               fetch_alternates(alt->base);
-               altbase = altbase->next;
-       }
-       return error("Unable to find %s under %s", sha1_to_hex(sha1),
-                    alt->base);
-}
-
-static inline int needs_quote(int ch)
-{
-       if (((ch >= 'A') && (ch <= 'Z'))
-                       || ((ch >= 'a') && (ch <= 'z'))
-                       || ((ch >= '0') && (ch <= '9'))
-                       || (ch == '/')
-                       || (ch == '-')
-                       || (ch == '.'))
-               return 0;
-       return 1;
-}
-
-static inline int hex(int v)
-{
-       if (v < 10) return '0' + v;
-       else return 'A' + v - 10;
-}
-
-static char *quote_ref_url(const char *base, const char *ref)
-{
-       const char *cp;
-       char *dp, *qref;
-       int len, baselen, ch;
-
-       baselen = strlen(base);
-       len = baselen + 7; /* "/refs/" + NUL */
-       for (cp = ref; (ch = *cp) != 0; cp++, len++)
-               if (needs_quote(ch))
-                       len += 2; /* extra two hex plus replacement % */
-       qref = xmalloc(len);
-       memcpy(qref, base, baselen);
-       memcpy(qref + baselen, "/refs/", 6);
-       for (cp = ref, dp = qref + baselen + 6; (ch = *cp) != 0; cp++) {
-               if (needs_quote(ch)) {
-                       *dp++ = '%';
-                       *dp++ = hex((ch >> 4) & 0xF);
-                       *dp++ = hex(ch & 0xF);
-               }
-               else
-                       *dp++ = ch;
-       }
-       *dp = 0;
-
-       return qref;
-}
-
-int fetch_ref(char *ref, unsigned char *sha1)
-{
-        char *url;
-        char hex[42];
-        struct buffer buffer;
-       const char *base = alt->base;
-       struct active_request_slot *slot;
-       struct slot_results results;
-        buffer.size = 41;
-        buffer.posn = 0;
-        buffer.buffer = hex;
-        hex[41] = '\0';
-
-       url = quote_ref_url(base, ref);
-       slot = get_active_slot();
-       slot->results = &results;
-       curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
-       curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
-       curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
-       curl_easy_setopt(slot->curl, CURLOPT_URL, url);
-       if (start_active_slot(slot)) {
-               run_active_slot(slot);
-               if (results.curl_result != CURLE_OK)
-                       return error("Couldn't get %s for %s\n%s",
-                                    url, ref, curl_errorstr);
-       } else {
-               return error("Unable to start request");
-       }
-
-        hex[40] = '\0';
-        get_sha1_hex(hex, sha1);
-        return 0;
-}
+#include "walker.h"
 
 int main(int argc, const char **argv)
 {
+       const char *prefix;
+       struct walker *walker;
+       int commits_on_stdin = 0;
        int commits;
        const char **write_ref = NULL;
        char **commit_id;
        const char *url;
-       char *s;
+       char *rewritten_url = NULL;
        int arg = 1;
        int rc = 0;
+       int get_tree = 0;
+       int get_history = 0;
+       int get_all = 0;
+       int get_verbosely = 0;
+       int get_recover = 0;
+
+       prefix = setup_git_directory();
 
-       setup_git_directory();
-       git_config(git_default_config);
+       git_config(git_default_config, NULL);
 
        while (arg < argc && argv[arg][0] == '-') {
                if (argv[arg][1] == 't') {
@@ -1020,45 +45,45 @@ int main(int argc, const char **argv)
                arg++;
        }
        if (argc < arg + 2 - commits_on_stdin) {
-               usage("git-http-fetch [-c] [-t] [-a] [-v] [--recover] [-w ref] [--stdin] commit-id url");
+               usage("git http-fetch [-c] [-t] [-a] [-v] [--recover] [-w ref] [--stdin] commit-id url");
                return 1;
        }
        if (commits_on_stdin) {
-               commits = pull_targets_stdin(&commit_id, &write_ref);
+               commits = walker_targets_stdin(&commit_id, &write_ref);
        } else {
                commit_id = (char **) &argv[arg++];
                commits = 1;
        }
        url = argv[arg];
+       if (url && url[strlen(url)-1] != '/') {
+               rewritten_url = xmalloc(strlen(url)+2);
+               strcpy(rewritten_url, url);
+               strcat(rewritten_url, "/");
+               url = rewritten_url;
+       }
 
-       http_init();
-
-       no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
-
-       alt = xmalloc(sizeof(*alt));
-       alt->base = xmalloc(strlen(url) + 1);
-       strcpy(alt->base, url);
-       for (s = alt->base + strlen(alt->base) - 1; *s == '/'; --s)
-               *s = 0;
-       alt->got_indices = 0;
-       alt->packs = NULL;
-       alt->next = NULL;
-
-       if (pull(commits, commit_id, write_ref, url))
-               rc = 1;
-
-       http_cleanup();
+       walker = get_http_walker(url, NULL);
+       walker->get_tree = get_tree;
+       walker->get_history = get_history;
+       walker->get_all = get_all;
+       walker->get_verbosely = get_verbosely;
+       walker->get_recover = get_recover;
 
-       curl_slist_free_all(no_pragma_header);
+       rc = walker_fetch(walker, commits, commit_id, write_ref, url);
 
        if (commits_on_stdin)
-               pull_targets_free(commits, commit_id, write_ref);
+               walker_targets_free(commits, commit_id, write_ref);
 
-       if (corrupt_object_found) {
+       if (walker->corrupt_object_found) {
                fprintf(stderr,
 "Some loose object were found to be corrupt, but they might be just\n"
 "a false '404 Not Found' error message sent with incorrect HTTP\n"
-"status code.  Suggest running git-fsck.\n");
+"status code.  Suggest running 'git fsck'.\n");
        }
+
+       walker_free(walker);
+
+       free(rewritten_url);
+
        return rc;
 }