ls-refs.c

   1 #include "cache.h"
   2 #include "repository.h"
   3 #include "refs.h"
   4 #include "remote.h"
   5 #include "strvec.h"
   6 #include "ls-refs.h"
   7 #include "pkt-line.h"
   8 #include "config.h"
   9
  10 static int config_read;
  11 static int advertise_unborn;
  12 static int allow_unborn;
  13
  14 static void ensure_config_read(void)
  15 {
  16         const char *str = NULL;
  17
  18         if (config_read)
  19                 return;
  20
  21         if (repo_config_get_string_tmp(the_repository, "lsrefs.unborn", &str)) {
  22                 /*
  23                  * If there is no such config, advertise and allow it by
  24                  * default.
  25                  */
  26                 advertise_unborn = 1;
  27                 allow_unborn = 1;
  28         } else {
  29                 if (!strcmp(str, "advertise")) {
  30                         advertise_unborn = 1;
  31                         allow_unborn = 1;
  32                 } else if (!strcmp(str, "allow")) {
  33                         allow_unborn = 1;
  34                 } else if (!strcmp(str, "ignore")) {
  35                         /* do nothing */
  36                 } else {
  37                         die(_("invalid value '%s' for lsrefs.unborn"), str);
  38                 }
  39         }
  40         config_read = 1;
  41 }
  42
  43 /*
  44  * If we see this many or more "ref-prefix" lines from the client, we consider
  45  * it "too many" and will avoid using the prefix feature entirely.
  46  */
  47 #define TOO_MANY_PREFIXES 65536
  48
  49 /*
  50  * Check if one of the prefixes is a prefix of the ref.
  51  * If no prefixes were provided, all refs match.
  52  */
  53 static int ref_match(const struct strvec *prefixes, const char *refname)
  54 {
  55         int i;
  56
  57         if (!prefixes->nr)
  58                 return 1; /* no restriction */
  59
  60         for (i = 0; i < prefixes->nr; i++) {
  61                 const char *prefix = prefixes->v[i];
  62
  63                 if (starts_with(refname, prefix))
  64                         return 1;
  65         }
  66
  67         return 0;
  68 }
  69
  70 struct ls_refs_data {
  71         unsigned peel;
  72         unsigned symrefs;
  73         struct strvec prefixes;
  74         struct strbuf buf;
  75         unsigned unborn : 1;
  76 };
  77
  78 static int send_ref(const char *refname, const struct object_id *oid,
  79                     int flag, void *cb_data)
  80 {
  81         struct ls_refs_data *data = cb_data;
  82         const char *refname_nons = strip_namespace(refname);
  83
  84         strbuf_reset(&data->buf);
  85
  86         if (ref_is_hidden(refname_nons, refname))
  87                 return 0;
  88
  89         if (!ref_match(&data->prefixes, refname_nons))
  90                 return 0;
  91
  92         if (oid)
  93                 strbuf_addf(&data->buf, "%s %s", oid_to_hex(oid), refname_nons);
  94         else
  95                 strbuf_addf(&data->buf, "unborn %s", refname_nons);
  96         if (data->symrefs && flag & REF_ISSYMREF) {
  97                 struct object_id unused;
  98                 const char *symref_target = resolve_ref_unsafe(refname, 0,
  99                                                                &unused,
 100                                                                &flag);
 101
 102                 if (!symref_target)
 103                         die("'%s' is a symref but it is not?", refname);
 104
 105                 strbuf_addf(&data->buf, " symref-target:%s",
 106                             strip_namespace(symref_target));
 107         }
 108
 109         if (data->peel && oid) {
 110                 struct object_id peeled;
 111                 if (!peel_iterated_oid(oid, &peeled))
 112                         strbuf_addf(&data->buf, " peeled:%s", oid_to_hex(&peeled));
 113         }
 114
 115         strbuf_addch(&data->buf, '\n');
 116         packet_fwrite(stdout, data->buf.buf, data->buf.len);
 117
 118         return 0;
 119 }
 120
 121 static void send_possibly_unborn_head(struct ls_refs_data *data)
 122 {
 123         struct strbuf namespaced = STRBUF_INIT;
 124         struct object_id oid;
 125         int flag;
 126         int oid_is_null;
 127
 128         strbuf_addf(&namespaced, "%sHEAD", get_git_namespace());
 129         if (!resolve_ref_unsafe(namespaced.buf, 0, &oid, &flag))
 130                 return; /* bad ref */
 131         oid_is_null = is_null_oid(&oid);
 132         if (!oid_is_null ||
 133             (data->unborn && data->symrefs && (flag & REF_ISSYMREF)))
 134                 send_ref(namespaced.buf, oid_is_null ? NULL : &oid, flag, data);
 135         strbuf_release(&namespaced);
 136 }
 137
 138 static int ls_refs_config(const char *var, const char *value, void *data)
 139 {
 140         /*
 141          * We only serve fetches over v2 for now, so respect only "uploadpack"
 142          * config. This may need to eventually be expanded to "receive", but we
 143          * don't yet know how that information will be passed to ls-refs.
 144          */
 145         return parse_hide_refs_config(var, value, "uploadpack");
 146 }
 147
 148 int ls_refs(struct repository *r, struct packet_reader *request)
 149 {
 150         struct ls_refs_data data;
 151
 152         memset(&data, 0, sizeof(data));
 153         strvec_init(&data.prefixes);
 154         strbuf_init(&data.buf, 0);
 155
 156         ensure_config_read();
 157         git_config(ls_refs_config, NULL);
 158
 159         while (packet_reader_read(request) == PACKET_READ_NORMAL) {
 160                 const char *arg = request->line;
 161                 const char *out;
 162
 163                 if (!strcmp("peel", arg))
 164                         data.peel = 1;
 165                 else if (!strcmp("symrefs", arg))
 166                         data.symrefs = 1;
 167                 else if (skip_prefix(arg, "ref-prefix ", &out)) {
 168                         if (data.prefixes.nr < TOO_MANY_PREFIXES)
 169                                 strvec_push(&data.prefixes, out);
 170                 }
 171                 else if (!strcmp("unborn", arg))
 172                         data.unborn = allow_unborn;
 173                 else
 174                         die(_("unexpected line: '%s'"), arg);
 175         }
 176
 177         if (request->status != PACKET_READ_FLUSH)
 178                 die(_("expected flush after ls-refs arguments"));
 179
 180         /*
 181          * If we saw too many prefixes, we must avoid using them at all; as
 182          * soon as we have any prefix, they are meant to form a comprehensive
 183          * list.
 184          */
 185         if (data.prefixes.nr >= TOO_MANY_PREFIXES)
 186                 strvec_clear(&data.prefixes);
 187
 188         send_possibly_unborn_head(&data);
 189         if (!data.prefixes.nr)
 190                 strvec_push(&data.prefixes, "");
 191         for_each_fullref_in_prefixes(get_git_namespace(), data.prefixes.v,
 192                                      send_ref, &data);
 193         packet_fflush(stdout);
 194         strvec_clear(&data.prefixes);
 195         strbuf_release(&data.buf);
 196         return 0;
 197 }
 198
 199 int ls_refs_advertise(struct repository *r, struct strbuf *value)
 200 {
 201         if (value) {
 202                 ensure_config_read();
 203                 if (advertise_unborn)
 204                         strbuf_addstr(value, "unborn");
 205         }
 206
 207         return 1;
 208 }