ls-refs.c

   1 #include "cache.h"
   2 #include "hex.h"
   3 #include "repository.h"
   4 #include "refs.h"
   5 #include "remote.h"
   6 #include "strvec.h"
   7 #include "ls-refs.h"
   8 #include "pkt-line.h"
   9 #include "config.h"
  10 #include "string-list.h"
  11
  12 static int config_read;
  13 static int advertise_unborn;
  14 static int allow_unborn;
  15
  16 static void ensure_config_read(void)
  17 {
  18         const char *str = NULL;
  19
  20         if (config_read)
  21                 return;
  22
  23         if (repo_config_get_string_tmp(the_repository, "lsrefs.unborn", &str)) {
  24                 /*
  25                  * If there is no such config, advertise and allow it by
  26                  * default.
  27                  */
  28                 advertise_unborn = 1;
  29                 allow_unborn = 1;
  30         } else {
  31                 if (!strcmp(str, "advertise")) {
  32                         advertise_unborn = 1;
  33                         allow_unborn = 1;
  34                 } else if (!strcmp(str, "allow")) {
  35                         allow_unborn = 1;
  36                 } else if (!strcmp(str, "ignore")) {
  37                         /* do nothing */
  38                 } else {
  39                         die(_("invalid value for '%s': '%s'"),
  40                             "lsrefs.unborn", str);
  41                 }
  42         }
  43         config_read = 1;
  44 }
  45
  46 /*
  47  * If we see this many or more "ref-prefix" lines from the client, we consider
  48  * it "too many" and will avoid using the prefix feature entirely.
  49  */
  50 #define TOO_MANY_PREFIXES 65536
  51
  52 /*
  53  * Check if one of the prefixes is a prefix of the ref.
  54  * If no prefixes were provided, all refs match.
  55  */
  56 static int ref_match(const struct strvec *prefixes, const char *refname)
  57 {
  58         int i;
  59
  60         if (!prefixes->nr)
  61                 return 1; /* no restriction */
  62
  63         for (i = 0; i < prefixes->nr; i++) {
  64                 const char *prefix = prefixes->v[i];
  65
  66                 if (starts_with(refname, prefix))
  67                         return 1;
  68         }
  69
  70         return 0;
  71 }
  72
  73 struct ls_refs_data {
  74         unsigned peel;
  75         unsigned symrefs;
  76         struct strvec prefixes;
  77         struct strbuf buf;
  78         struct string_list hidden_refs;
  79         unsigned unborn : 1;
  80 };
  81
  82 static int send_ref(const char *refname, const struct object_id *oid,
  83                     int flag, void *cb_data)
  84 {
  85         struct ls_refs_data *data = cb_data;
  86         const char *refname_nons = strip_namespace(refname);
  87
  88         strbuf_reset(&data->buf);
  89
  90         if (ref_is_hidden(refname_nons, refname, &data->hidden_refs))
  91                 return 0;
  92
  93         if (!ref_match(&data->prefixes, refname_nons))
  94                 return 0;
  95
  96         if (oid)
  97                 strbuf_addf(&data->buf, "%s %s", oid_to_hex(oid), refname_nons);
  98         else
  99                 strbuf_addf(&data->buf, "unborn %s", refname_nons);
 100         if (data->symrefs && flag & REF_ISSYMREF) {
 101                 struct object_id unused;
 102                 const char *symref_target = resolve_ref_unsafe(refname, 0,
 103                                                                &unused,
 104                                                                &flag);
 105
 106                 if (!symref_target)
 107                         die("'%s' is a symref but it is not?", refname);
 108
 109                 strbuf_addf(&data->buf, " symref-target:%s",
 110                             strip_namespace(symref_target));
 111         }
 112
 113         if (data->peel && oid) {
 114                 struct object_id peeled;
 115                 if (!peel_iterated_oid(oid, &peeled))
 116                         strbuf_addf(&data->buf, " peeled:%s", oid_to_hex(&peeled));
 117         }
 118
 119         strbuf_addch(&data->buf, '\n');
 120         packet_fwrite(stdout, data->buf.buf, data->buf.len);
 121
 122         return 0;
 123 }
 124
 125 static void send_possibly_unborn_head(struct ls_refs_data *data)
 126 {
 127         struct strbuf namespaced = STRBUF_INIT;
 128         struct object_id oid;
 129         int flag;
 130         int oid_is_null;
 131
 132         strbuf_addf(&namespaced, "%sHEAD", get_git_namespace());
 133         if (!resolve_ref_unsafe(namespaced.buf, 0, &oid, &flag))
 134                 return; /* bad ref */
 135         oid_is_null = is_null_oid(&oid);
 136         if (!oid_is_null ||
 137             (data->unborn && data->symrefs && (flag & REF_ISSYMREF)))
 138                 send_ref(namespaced.buf, oid_is_null ? NULL : &oid, flag, data);
 139         strbuf_release(&namespaced);
 140 }
 141
 142 static int ls_refs_config(const char *var, const char *value,
 143                           void *cb_data)
 144 {
 145         struct ls_refs_data *data = cb_data;
 146         /*
 147          * We only serve fetches over v2 for now, so respect only "uploadpack"
 148          * config. This may need to eventually be expanded to "receive", but we
 149          * don't yet know how that information will be passed to ls-refs.
 150          */
 151         return parse_hide_refs_config(var, value, "uploadpack", &data->hidden_refs);
 152 }
 153
 154 int ls_refs(struct repository *r, struct packet_reader *request)
 155 {
 156         struct ls_refs_data data;
 157
 158         memset(&data, 0, sizeof(data));
 159         strvec_init(&data.prefixes);
 160         strbuf_init(&data.buf, 0);
 161         string_list_init_dup(&data.hidden_refs);
 162
 163         ensure_config_read();
 164         git_config(ls_refs_config, &data);
 165
 166         while (packet_reader_read(request) == PACKET_READ_NORMAL) {
 167                 const char *arg = request->line;
 168                 const char *out;
 169
 170                 if (!strcmp("peel", arg))
 171                         data.peel = 1;
 172                 else if (!strcmp("symrefs", arg))
 173                         data.symrefs = 1;
 174                 else if (skip_prefix(arg, "ref-prefix ", &out)) {
 175                         if (data.prefixes.nr < TOO_MANY_PREFIXES)
 176                                 strvec_push(&data.prefixes, out);
 177                 }
 178                 else if (!strcmp("unborn", arg))
 179                         data.unborn = allow_unborn;
 180                 else
 181                         die(_("unexpected line: '%s'"), arg);
 182         }
 183
 184         if (request->status != PACKET_READ_FLUSH)
 185                 die(_("expected flush after ls-refs arguments"));
 186
 187         /*
 188          * If we saw too many prefixes, we must avoid using them at all; as
 189          * soon as we have any prefix, they are meant to form a comprehensive
 190          * list.
 191          */
 192         if (data.prefixes.nr >= TOO_MANY_PREFIXES)
 193                 strvec_clear(&data.prefixes);
 194
 195         send_possibly_unborn_head(&data);
 196         if (!data.prefixes.nr)
 197                 strvec_push(&data.prefixes, "");
 198         refs_for_each_fullref_in_prefixes(get_main_ref_store(r),
 199                                           get_git_namespace(), data.prefixes.v,
 200                                           send_ref, &data);
 201         packet_fflush(stdout);
 202         strvec_clear(&data.prefixes);
 203         strbuf_release(&data.buf);
 204         string_list_clear(&data.hidden_refs, 0);
 205         return 0;
 206 }
 207
 208 int ls_refs_advertise(struct repository *r, struct strbuf *value)
 209 {
 210         if (value) {
 211                 ensure_config_read();
 212                 if (advertise_unborn)
 213                         strbuf_addstr(value, "unborn");
 214         }
 215
 216         return 1;
 217 }