ls-refs.c

   1 #include "git-compat-util.h"
   2 #include "environment.h"
   3 #include "gettext.h"
   4 #include "hash.h"
   5 #include "hex.h"
   6 #include "repository.h"
   7 #include "refs.h"
   8 #include "remote.h"
   9 #include "strvec.h"
  10 #include "ls-refs.h"
  11 #include "pkt-line.h"
  12 #include "config.h"
  13 #include "string-list.h"
  14
  15 static enum {
  16         UNBORN_IGNORE = 0,
  17         UNBORN_ALLOW,
  18         UNBORN_ADVERTISE /* implies ALLOW */
  19 } unborn_config(struct repository *r)
  20 {
  21         const char *str = NULL;
  22
  23         if (repo_config_get_string_tmp(r, "lsrefs.unborn", &str)) {
  24                 /*
  25                  * If there is no such config, advertise and allow it by
  26                  * default.
  27                  */
  28                 return UNBORN_ADVERTISE;
  29         } else {
  30                 if (!strcmp(str, "advertise")) {
  31                         return UNBORN_ADVERTISE;
  32                 } else if (!strcmp(str, "allow")) {
  33                         return UNBORN_ALLOW;
  34                 } else if (!strcmp(str, "ignore")) {
  35                         return UNBORN_IGNORE;
  36                 } else {
  37                         die(_("invalid value for '%s': '%s'"),
  38                             "lsrefs.unborn", str);
  39                 }
  40         }
  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         struct strvec hidden_refs;
  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, &data->hidden_refs))
  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,
 140                           const struct config_context *ctx UNUSED,
 141                           void *cb_data)
 142 {
 143         struct ls_refs_data *data = cb_data;
 144         /*
 145          * We only serve fetches over v2 for now, so respect only "uploadpack"
 146          * config. This may need to eventually be expanded to "receive", but we
 147          * don't yet know how that information will be passed to ls-refs.
 148          */
 149         return parse_hide_refs_config(var, value, "uploadpack", &data->hidden_refs);
 150 }
 151
 152 int ls_refs(struct repository *r, struct packet_reader *request)
 153 {
 154         struct ls_refs_data data;
 155
 156         memset(&data, 0, sizeof(data));
 157         strvec_init(&data.prefixes);
 158         strbuf_init(&data.buf, 0);
 159         strvec_init(&data.hidden_refs);
 160
 161         git_config(ls_refs_config, &data);
 162
 163         while (packet_reader_read(request) == PACKET_READ_NORMAL) {
 164                 const char *arg = request->line;
 165                 const char *out;
 166
 167                 if (!strcmp("peel", arg))
 168                         data.peel = 1;
 169                 else if (!strcmp("symrefs", arg))
 170                         data.symrefs = 1;
 171                 else if (skip_prefix(arg, "ref-prefix ", &out)) {
 172                         if (data.prefixes.nr < TOO_MANY_PREFIXES)
 173                                 strvec_push(&data.prefixes, out);
 174                 }
 175                 else if (!strcmp("unborn", arg))
 176                         data.unborn = !!unborn_config(r);
 177                 else
 178                         die(_("unexpected line: '%s'"), arg);
 179         }
 180
 181         if (request->status != PACKET_READ_FLUSH)
 182                 die(_("expected flush after ls-refs arguments"));
 183
 184         /*
 185          * If we saw too many prefixes, we must avoid using them at all; as
 186          * soon as we have any prefix, they are meant to form a comprehensive
 187          * list.
 188          */
 189         if (data.prefixes.nr >= TOO_MANY_PREFIXES)
 190                 strvec_clear(&data.prefixes);
 191
 192         send_possibly_unborn_head(&data);
 193         if (!data.prefixes.nr)
 194                 strvec_push(&data.prefixes, "");
 195         refs_for_each_fullref_in_prefixes(get_main_ref_store(r),
 196                                           get_git_namespace(), data.prefixes.v,
 197                                           hidden_refs_to_excludes(&data.hidden_refs),
 198                                           send_ref, &data);
 199         packet_fflush(stdout);
 200         strvec_clear(&data.prefixes);
 201         strbuf_release(&data.buf);
 202         strvec_clear(&data.hidden_refs);
 203         return 0;
 204 }
 205
 206 int ls_refs_advertise(struct repository *r, struct strbuf *value)
 207 {
 208         if (value && unborn_config(r) == UNBORN_ADVERTISE)
 209                 strbuf_addstr(value, "unborn");
 210
 211         return 1;
 212 }