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 for '%s': '%s'"),
  38                             "lsrefs.unborn", str);
  39                 }
  40         }
  41         config_read = 1;
  42 }
  43
  44 /*
  45  * If we see this many or more "ref-prefix" lines from the client, we consider
  46  * it "too many" and will avoid using the prefix feature entirely.
  47  */
  48 #define TOO_MANY_PREFIXES 65536
  49
  50 /*
  51  * Check if one of the prefixes is a prefix of the ref.
  52  * If no prefixes were provided, all refs match.
  53  */
  54 static int ref_match(const struct strvec *prefixes, const char *refname)
  55 {
  56         int i;
  57
  58         if (!prefixes->nr)
  59                 return 1; /* no restriction */
  60
  61         for (i = 0; i < prefixes->nr; i++) {
  62                 const char *prefix = prefixes->v[i];
  63
  64                 if (starts_with(refname, prefix))
  65                         return 1;
  66         }
  67
  68         return 0;
  69 }
  70
  71 struct ls_refs_data {
  72         unsigned peel;
  73         unsigned symrefs;
  74         struct strvec prefixes;
  75         struct strbuf buf;
  76         unsigned unborn : 1;
  77 };
  78
  79 static int send_ref(const char *refname, const struct object_id *oid,
  80                     int flag, void *cb_data)
  81 {
  82         struct ls_refs_data *data = cb_data;
  83         const char *refname_nons = strip_namespace(refname);
  84
  85         strbuf_reset(&data->buf);
  86
  87         if (ref_is_hidden(refname_nons, refname))
  88                 return 0;
  89
  90         if (!ref_match(&data->prefixes, refname_nons))
  91                 return 0;
  92
  93         if (oid)
  94                 strbuf_addf(&data->buf, "%s %s", oid_to_hex(oid), refname_nons);
  95         else
  96                 strbuf_addf(&data->buf, "unborn %s", refname_nons);
  97         if (data->symrefs && flag & REF_ISSYMREF) {
  98                 struct object_id unused;
  99                 const char *symref_target = resolve_ref_unsafe(refname, 0,
 100                                                                &unused,
 101                                                                &flag);
 102
 103                 if (!symref_target)
 104                         die("'%s' is a symref but it is not?", refname);
 105
 106                 strbuf_addf(&data->buf, " symref-target:%s",
 107                             strip_namespace(symref_target));
 108         }
 109
 110         if (data->peel && oid) {
 111                 struct object_id peeled;
 112                 if (!peel_iterated_oid(oid, &peeled))
 113                         strbuf_addf(&data->buf, " peeled:%s", oid_to_hex(&peeled));
 114         }
 115
 116         strbuf_addch(&data->buf, '\n');
 117         packet_fwrite(stdout, data->buf.buf, data->buf.len);
 118
 119         return 0;
 120 }
 121
 122 static void send_possibly_unborn_head(struct ls_refs_data *data)
 123 {
 124         struct strbuf namespaced = STRBUF_INIT;
 125         struct object_id oid;
 126         int flag;
 127         int oid_is_null;
 128
 129         strbuf_addf(&namespaced, "%sHEAD", get_git_namespace());
 130         if (!resolve_ref_unsafe(namespaced.buf, 0, &oid, &flag))
 131                 return; /* bad ref */
 132         oid_is_null = is_null_oid(&oid);
 133         if (!oid_is_null ||
 134             (data->unborn && data->symrefs && (flag & REF_ISSYMREF)))
 135                 send_ref(namespaced.buf, oid_is_null ? NULL : &oid, flag, data);
 136         strbuf_release(&namespaced);
 137 }
 138
 139 static int ls_refs_config(const char *var, const char *value, void *data)
 140 {
 141         /*
 142          * We only serve fetches over v2 for now, so respect only "uploadpack"
 143          * config. This may need to eventually be expanded to "receive", but we
 144          * don't yet know how that information will be passed to ls-refs.
 145          */
 146         return parse_hide_refs_config(var, value, "uploadpack");
 147 }
 148
 149 int ls_refs(struct repository *r, struct packet_reader *request)
 150 {
 151         struct ls_refs_data data;
 152
 153         memset(&data, 0, sizeof(data));
 154         strvec_init(&data.prefixes);
 155         strbuf_init(&data.buf, 0);
 156
 157         ensure_config_read();
 158         git_config(ls_refs_config, NULL);
 159
 160         while (packet_reader_read(request) == PACKET_READ_NORMAL) {
 161                 const char *arg = request->line;
 162                 const char *out;
 163
 164                 if (!strcmp("peel", arg))
 165                         data.peel = 1;
 166                 else if (!strcmp("symrefs", arg))
 167                         data.symrefs = 1;
 168                 else if (skip_prefix(arg, "ref-prefix ", &out)) {
 169                         if (data.prefixes.nr < TOO_MANY_PREFIXES)
 170                                 strvec_push(&data.prefixes, out);
 171                 }
 172                 else if (!strcmp("unborn", arg))
 173                         data.unborn = allow_unborn;
 174                 else
 175                         die(_("unexpected line: '%s'"), arg);
 176         }
 177
 178         if (request->status != PACKET_READ_FLUSH)
 179                 die(_("expected flush after ls-refs arguments"));
 180
 181         /*
 182          * If we saw too many prefixes, we must avoid using them at all; as
 183          * soon as we have any prefix, they are meant to form a comprehensive
 184          * list.
 185          */
 186         if (data.prefixes.nr >= TOO_MANY_PREFIXES)
 187                 strvec_clear(&data.prefixes);
 188
 189         send_possibly_unborn_head(&data);
 190         if (!data.prefixes.nr)
 191                 strvec_push(&data.prefixes, "");
 192         for_each_fullref_in_prefixes(get_git_namespace(), data.prefixes.v,
 193                                      send_ref, &data);
 194         packet_fflush(stdout);
 195         strvec_clear(&data.prefixes);
 196         strbuf_release(&data.buf);
 197         return 0;
 198 }
 199
 200 int ls_refs_advertise(struct repository *r, struct strbuf *value)
 201 {
 202         if (value) {
 203                 ensure_config_read();
 204                 if (advertise_unborn)
 205                         strbuf_addstr(value, "unborn");
 206         }
 207
 208         return 1;
 209 }