doc hash-function-transition: move rationale upwards
[git] / connected.c
1 #include "cache.h"
2 #include "object-store.h"
3 #include "run-command.h"
4 #include "sigchain.h"
5 #include "connected.h"
6 #include "transport.h"
7 #include "packfile.h"
8 #include "promisor-remote.h"
9
10 /*
11  * If we feed all the commits we want to verify to this command
12  *
13  *  $ git rev-list --objects --stdin --not --all
14  *
15  * and if it does not error out, that means everything reachable from
16  * these commits locally exists and is connected to our existing refs.
17  * Note that this does _not_ validate the individual objects.
18  *
19  * Returns 0 if everything is connected, non-zero otherwise.
20  */
21 int check_connected(oid_iterate_fn fn, void *cb_data,
22                     struct check_connected_options *opt)
23 {
24         struct child_process rev_list = CHILD_PROCESS_INIT;
25         FILE *rev_list_in;
26         struct check_connected_options defaults = CHECK_CONNECTED_INIT;
27         struct object_id oid;
28         int err = 0;
29         struct packed_git *new_pack = NULL;
30         struct transport *transport;
31         size_t base_len;
32
33         if (!opt)
34                 opt = &defaults;
35         transport = opt->transport;
36
37         if (fn(cb_data, &oid)) {
38                 if (opt->err_fd)
39                         close(opt->err_fd);
40                 return err;
41         }
42
43         if (transport && transport->smart_options &&
44             transport->smart_options->self_contained_and_connected &&
45             transport->pack_lockfiles.nr == 1 &&
46             strip_suffix(transport->pack_lockfiles.items[0].string,
47                          ".keep", &base_len)) {
48                 struct strbuf idx_file = STRBUF_INIT;
49                 strbuf_add(&idx_file, transport->pack_lockfiles.items[0].string,
50                            base_len);
51                 strbuf_addstr(&idx_file, ".idx");
52                 new_pack = add_packed_git(idx_file.buf, idx_file.len, 1);
53                 strbuf_release(&idx_file);
54         }
55
56         if (has_promisor_remote()) {
57                 /*
58                  * For partial clones, we don't want to have to do a regular
59                  * connectivity check because we have to enumerate and exclude
60                  * all promisor objects (slow), and then the connectivity check
61                  * itself becomes a no-op because in a partial clone every
62                  * object is a promisor object. Instead, just make sure we
63                  * received, in a promisor packfile, the objects pointed to by
64                  * each wanted ref.
65                  *
66                  * Before checking for promisor packs, be sure we have the
67                  * latest pack-files loaded into memory.
68                  */
69                 reprepare_packed_git(the_repository);
70                 do {
71                         struct packed_git *p;
72
73                         for (p = get_all_packs(the_repository); p; p = p->next) {
74                                 if (!p->pack_promisor)
75                                         continue;
76                                 if (find_pack_entry_one(oid.hash, p))
77                                         goto promisor_pack_found;
78                         }
79                         /*
80                          * Fallback to rev-list with oid and the rest of the
81                          * object IDs provided by fn.
82                          */
83                         goto no_promisor_pack_found;
84 promisor_pack_found:
85                         ;
86                 } while (!fn(cb_data, &oid));
87                 return 0;
88         }
89
90 no_promisor_pack_found:
91         if (opt->shallow_file) {
92                 strvec_push(&rev_list.args, "--shallow-file");
93                 strvec_push(&rev_list.args, opt->shallow_file);
94         }
95         strvec_push(&rev_list.args,"rev-list");
96         strvec_push(&rev_list.args, "--objects");
97         strvec_push(&rev_list.args, "--stdin");
98         if (has_promisor_remote())
99                 strvec_push(&rev_list.args, "--exclude-promisor-objects");
100         if (!opt->is_deepening_fetch) {
101                 strvec_push(&rev_list.args, "--not");
102                 strvec_push(&rev_list.args, "--all");
103         }
104         strvec_push(&rev_list.args, "--quiet");
105         strvec_push(&rev_list.args, "--alternate-refs");
106         if (opt->progress)
107                 strvec_pushf(&rev_list.args, "--progress=%s",
108                              _("Checking connectivity"));
109
110         rev_list.git_cmd = 1;
111         rev_list.env = opt->env;
112         rev_list.in = -1;
113         rev_list.no_stdout = 1;
114         if (opt->err_fd)
115                 rev_list.err = opt->err_fd;
116         else
117                 rev_list.no_stderr = opt->quiet;
118
119         if (start_command(&rev_list))
120                 return error(_("Could not run 'git rev-list'"));
121
122         sigchain_push(SIGPIPE, SIG_IGN);
123
124         rev_list_in = xfdopen(rev_list.in, "w");
125
126         do {
127                 /*
128                  * If index-pack already checked that:
129                  * - there are no dangling pointers in the new pack
130                  * - the pack is self contained
131                  * Then if the updated ref is in the new pack, then we
132                  * are sure the ref is good and not sending it to
133                  * rev-list for verification.
134                  */
135                 if (new_pack && find_pack_entry_one(oid.hash, new_pack))
136                         continue;
137
138                 if (fprintf(rev_list_in, "%s\n", oid_to_hex(&oid)) < 0)
139                         break;
140         } while (!fn(cb_data, &oid));
141
142         if (ferror(rev_list_in) || fflush(rev_list_in)) {
143                 if (errno != EPIPE && errno != EINVAL)
144                         error_errno(_("failed write to rev-list"));
145                 err = -1;
146         }
147
148         if (fclose(rev_list_in))
149                 err = error_errno(_("failed to close rev-list's stdin"));
150
151         sigchain_pop(SIGPIPE);
152         return finish_command(&rev_list) || err;
153 }