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 enum {
  13         UNBORN_IGNORE = 0,
  14         UNBORN_ALLOW,
  15         UNBORN_ADVERTISE /* implies ALLOW */
  16 } unborn_config(struct repository *r)
  17 {
  18         const char *str = NULL;
  19
  20         if (repo_config_get_string_tmp(r, "lsrefs.unborn", &str)) {
  21                 /*
  22                  * If there is no such config, advertise and allow it by
  23                  * default.
  24                  */
  25                 return UNBORN_ADVERTISE;
  26         } else {
  27                 if (!strcmp(str, "advertise")) {
  28                         return UNBORN_ADVERTISE;
  29                 } else if (!strcmp(str, "allow")) {
  30                         return UNBORN_ALLOW;
  31                 } else if (!strcmp(str, "ignore")) {
  32                         return UNBORN_IGNORE;
  33                 } else {
  34                         die(_("invalid value for '%s': '%s'"),
  35                             "lsrefs.unborn", str);
  36                 }
  37         }
  38 }
  39
  40 /*
  41  * If we see this many or more "ref-prefix" lines from the client, we consider
  42  * it "too many" and will avoid using the prefix feature entirely.
  43  */
  44 #define TOO_MANY_PREFIXES 65536
  45
  46 /*
  47  * Check if one of the prefixes is a prefix of the ref.
  48  * If no prefixes were provided, all refs match.
  49  */
  50 static int ref_match(const struct strvec *prefixes, const char *refname)
  51 {
  52         int i;
  53
  54         if (!prefixes->nr)
  55                 return 1; /* no restriction */
  56
  57         for (i = 0; i < prefixes->nr; i++) {
  58                 const char *prefix = prefixes->v[i];
  59
  60                 if (starts_with(refname, prefix))
  61                         return 1;
  62         }
  63
  64         return 0;
  65 }
  66
  67 struct ls_refs_data {
  68         unsigned peel;
  69         unsigned symrefs;
  70         struct strvec prefixes;
  71         struct strbuf buf;
  72         struct string_list hidden_refs;
  73         unsigned unborn : 1;
  74 };
  75
  76 static int send_ref(const char *refname, const struct object_id *oid,
  77                     int flag, void *cb_data)
  78 {
  79         struct ls_refs_data *data = cb_data;
  80         const char *refname_nons = strip_namespace(refname);
  81
  82         strbuf_reset(&data->buf);
  83
  84         if (ref_is_hidden(refname_nons, refname, &data->hidden_refs))
  85                 return 0;
  86
  87         if (!ref_match(&data->prefixes, refname_nons))
  88                 return 0;
  89
  90         if (oid)
  91                 strbuf_addf(&data->buf, "%s %s", oid_to_hex(oid), refname_nons);
  92         else
  93                 strbuf_addf(&data->buf, "unborn %s", refname_nons);
  94         if (data->symrefs && flag & REF_ISSYMREF) {
  95                 struct object_id unused;
  96                 const char *symref_target = resolve_ref_unsafe(refname, 0,
  97                                                                &unused,
  98                                                                &flag);
  99
 100                 if (!symref_target)
 101                         die("'%s' is a symref but it is not?", refname);
 102
 103                 strbuf_addf(&data->buf, " symref-target:%s",
 104                             strip_namespace(symref_target));
 105         }
 106
 107         if (data->peel && oid) {
 108                 struct object_id peeled;
 109                 if (!peel_iterated_oid(oid, &peeled))
 110                         strbuf_addf(&data->buf, " peeled:%s", oid_to_hex(&peeled));
 111         }
 112
 113         strbuf_addch(&data->buf, '\n');
 114         packet_fwrite(stdout, data->buf.buf, data->buf.len);
 115
 116         return 0;
 117 }
 118
 119 static void send_possibly_unborn_head(struct ls_refs_data *data)
 120 {
 121         struct strbuf namespaced = STRBUF_INIT;
 122         struct object_id oid;
 123         int flag;
 124         int oid_is_null;
 125
 126         strbuf_addf(&namespaced, "%sHEAD", get_git_namespace());
 127         if (!resolve_ref_unsafe(namespaced.buf, 0, &oid, &flag))
 128                 return; /* bad ref */
 129         oid_is_null = is_null_oid(&oid);
 130         if (!oid_is_null ||
 131             (data->unborn && data->symrefs && (flag & REF_ISSYMREF)))
 132                 send_ref(namespaced.buf, oid_is_null ? NULL : &oid, flag, data);
 133         strbuf_release(&namespaced);
 134 }
 135
 136 static int ls_refs_config(const char *var, const char *value,
 137                           void *cb_data)
 138 {
 139         struct ls_refs_data *data = cb_data;
 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", &data->hidden_refs);
 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         string_list_init_dup(&data.hidden_refs);
 156
 157         git_config(ls_refs_config, &data);
 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 = !!unborn_config(r);
 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         refs_for_each_fullref_in_prefixes(get_main_ref_store(r),
 192                                           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         string_list_clear(&data.hidden_refs, 0);
 198         return 0;
 199 }
 200
 201 int ls_refs_advertise(struct repository *r, struct strbuf *value)
 202 {
 203         if (value && unborn_config(r) == UNBORN_ADVERTISE)
 204                 strbuf_addstr(value, "unborn");
 205
 206         return 1;
 207 }