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 #include "string-list.h"
  10
  11 static int config_read;
  12 static int advertise_unborn;
  13 static int allow_unborn;
  14
  15 static void ensure_config_read(void)
  16 {
  17         const char *str = NULL;
  18
  19         if (config_read)
  20                 return;
  21
  22         if (repo_config_get_string_tmp(the_repository, "lsrefs.unborn", &str)) {
  23                 /*
  24                  * If there is no such config, advertise and allow it by
  25                  * default.
  26                  */
  27                 advertise_unborn = 1;
  28                 allow_unborn = 1;
  29         } else {
  30                 if (!strcmp(str, "advertise")) {
  31                         advertise_unborn = 1;
  32                         allow_unborn = 1;
  33                 } else if (!strcmp(str, "allow")) {
  34                         allow_unborn = 1;
  35                 } else if (!strcmp(str, "ignore")) {
  36                         /* do nothing */
  37                 } else {
  38                         die(_("invalid value for '%s': '%s'"),
  39                             "lsrefs.unborn", str);
  40                 }
  41         }
  42         config_read = 1;
  43 }
  44
  45 /*
  46  * If we see this many or more "ref-prefix" lines from the client, we consider
  47  * it "too many" and will avoid using the prefix feature entirely.
  48  */
  49 #define TOO_MANY_PREFIXES 65536
  50
  51 /*
  52  * Check if one of the prefixes is a prefix of the ref.
  53  * If no prefixes were provided, all refs match.
  54  */
  55 static int ref_match(const struct strvec *prefixes, const char *refname)
  56 {
  57         int i;
  58
  59         if (!prefixes->nr)
  60                 return 1; /* no restriction */
  61
  62         for (i = 0; i < prefixes->nr; i++) {
  63                 const char *prefix = prefixes->v[i];
  64
  65                 if (starts_with(refname, prefix))
  66                         return 1;
  67         }
  68
  69         return 0;
  70 }
  71
  72 struct ls_refs_data {
  73         unsigned peel;
  74         unsigned symrefs;
  75         struct strvec prefixes;
  76         struct strbuf buf;
  77         struct string_list hidden_refs;
  78         unsigned unborn : 1;
  79 };
  80
  81 static int send_ref(const char *refname, const struct object_id *oid,
  82                     int flag, void *cb_data)
  83 {
  84         struct ls_refs_data *data = cb_data;
  85         const char *refname_nons = strip_namespace(refname);
  86
  87         strbuf_reset(&data->buf);
  88
  89         if (ref_is_hidden(refname_nons, refname, &data->hidden_refs))
  90                 return 0;
  91
  92         if (!ref_match(&data->prefixes, refname_nons))
  93                 return 0;
  94
  95         if (oid)
  96                 strbuf_addf(&data->buf, "%s %s", oid_to_hex(oid), refname_nons);
  97         else
  98                 strbuf_addf(&data->buf, "unborn %s", refname_nons);
  99         if (data->symrefs && flag & REF_ISSYMREF) {
 100                 struct object_id unused;
 101                 const char *symref_target = resolve_ref_unsafe(refname, 0,
 102                                                                &unused,
 103                                                                &flag);
 104
 105                 if (!symref_target)
 106                         die("'%s' is a symref but it is not?", refname);
 107
 108                 strbuf_addf(&data->buf, " symref-target:%s",
 109                             strip_namespace(symref_target));
 110         }
 111
 112         if (data->peel && oid) {
 113                 struct object_id peeled;
 114                 if (!peel_iterated_oid(oid, &peeled))
 115                         strbuf_addf(&data->buf, " peeled:%s", oid_to_hex(&peeled));
 116         }
 117
 118         strbuf_addch(&data->buf, '\n');
 119         packet_fwrite(stdout, data->buf.buf, data->buf.len);
 120
 121         return 0;
 122 }
 123
 124 static void send_possibly_unborn_head(struct ls_refs_data *data)
 125 {
 126         struct strbuf namespaced = STRBUF_INIT;
 127         struct object_id oid;
 128         int flag;
 129         int oid_is_null;
 130
 131         strbuf_addf(&namespaced, "%sHEAD", get_git_namespace());
 132         if (!resolve_ref_unsafe(namespaced.buf, 0, &oid, &flag))
 133                 return; /* bad ref */
 134         oid_is_null = is_null_oid(&oid);
 135         if (!oid_is_null ||
 136             (data->unborn && data->symrefs && (flag & REF_ISSYMREF)))
 137                 send_ref(namespaced.buf, oid_is_null ? NULL : &oid, flag, data);
 138         strbuf_release(&namespaced);
 139 }
 140
 141 static int ls_refs_config(const char *var, const char *value,
 142                           void *cb_data)
 143 {
 144         struct ls_refs_data *data = cb_data;
 145         /*
 146          * We only serve fetches over v2 for now, so respect only "uploadpack"
 147          * config. This may need to eventually be expanded to "receive", but we
 148          * don't yet know how that information will be passed to ls-refs.
 149          */
 150         return parse_hide_refs_config(var, value, "uploadpack", &data->hidden_refs);
 151 }
 152
 153 int ls_refs(struct repository *r, struct packet_reader *request)
 154 {
 155         struct ls_refs_data data;
 156
 157         memset(&data, 0, sizeof(data));
 158         strvec_init(&data.prefixes);
 159         strbuf_init(&data.buf, 0);
 160         string_list_init_dup(&data.hidden_refs);
 161
 162         ensure_config_read();
 163         git_config(ls_refs_config, &data);
 164
 165         while (packet_reader_read(request) == PACKET_READ_NORMAL) {
 166                 const char *arg = request->line;
 167                 const char *out;
 168
 169                 if (!strcmp("peel", arg))
 170                         data.peel = 1;
 171                 else if (!strcmp("symrefs", arg))
 172                         data.symrefs = 1;
 173                 else if (skip_prefix(arg, "ref-prefix ", &out)) {
 174                         if (data.prefixes.nr < TOO_MANY_PREFIXES)
 175                                 strvec_push(&data.prefixes, out);
 176                 }
 177                 else if (!strcmp("unborn", arg))
 178                         data.unborn = allow_unborn;
 179                 else
 180                         die(_("unexpected line: '%s'"), arg);
 181         }
 182
 183         if (request->status != PACKET_READ_FLUSH)
 184                 die(_("expected flush after ls-refs arguments"));
 185
 186         /*
 187          * If we saw too many prefixes, we must avoid using them at all; as
 188          * soon as we have any prefix, they are meant to form a comprehensive
 189          * list.
 190          */
 191         if (data.prefixes.nr >= TOO_MANY_PREFIXES)
 192                 strvec_clear(&data.prefixes);
 193
 194         send_possibly_unborn_head(&data);
 195         if (!data.prefixes.nr)
 196                 strvec_push(&data.prefixes, "");
 197         for_each_fullref_in_prefixes(get_git_namespace(), data.prefixes.v,
 198                                      send_ref, &data);
 199         packet_fflush(stdout);
 200         strvec_clear(&data.prefixes);
 201         strbuf_release(&data.buf);
 202         string_list_clear(&data.hidden_refs, 0);
 203         return 0;
 204 }
 205
 206 int ls_refs_advertise(struct repository *r, struct strbuf *value)
 207 {
 208         if (value) {
 209                 ensure_config_read();
 210                 if (advertise_unborn)
 211                         strbuf_addstr(value, "unborn");
 212         }
 213
 214         return 1;
 215 }