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 "strvec.h"
   9 #include "ls-refs.h"
  10 #include "pkt-line.h"
  11 #include "config.h"
  12 #include "string-list.h"
  13
  14 static enum {
  15         UNBORN_IGNORE = 0,
  16         UNBORN_ALLOW,
  17         UNBORN_ADVERTISE /* implies ALLOW */
  18 } unborn_config(struct repository *r)
  19 {
  20         const char *str = NULL;
  21
  22         if (repo_config_get_string_tmp(r, "lsrefs.unborn", &str)) {
  23                 /*
  24                  * If there is no such config, advertise and allow it by
  25                  * default.
  26                  */
  27                 return UNBORN_ADVERTISE;
  28         } else {
  29                 if (!strcmp(str, "advertise")) {
  30                         return UNBORN_ADVERTISE;
  31                 } else if (!strcmp(str, "allow")) {
  32                         return UNBORN_ALLOW;
  33                 } else if (!strcmp(str, "ignore")) {
  34                         return UNBORN_IGNORE;
  35                 } else {
  36                         die(_("invalid value for '%s': '%s'"),
  37                             "lsrefs.unborn", str);
  38                 }
  39         }
  40 }
  41
  42 /*
  43  * If we see this many or more "ref-prefix" lines from the client, we consider
  44  * it "too many" and will avoid using the prefix feature entirely.
  45  */
  46 #define TOO_MANY_PREFIXES 65536
  47
  48 /*
  49  * Check if one of the prefixes is a prefix of the ref.
  50  * If no prefixes were provided, all refs match.
  51  */
  52 static int ref_match(const struct strvec *prefixes, const char *refname)
  53 {
  54         int i;
  55
  56         if (!prefixes->nr)
  57                 return 1; /* no restriction */
  58
  59         for (i = 0; i < prefixes->nr; i++) {
  60                 const char *prefix = prefixes->v[i];
  61
  62                 if (starts_with(refname, prefix))
  63                         return 1;
  64         }
  65
  66         return 0;
  67 }
  68
  69 struct ls_refs_data {
  70         unsigned peel;
  71         unsigned symrefs;
  72         struct strvec prefixes;
  73         struct strbuf buf;
  74         struct strvec hidden_refs;
  75         unsigned unborn : 1;
  76 };
  77
  78 static int send_ref(const char *refname, const struct object_id *oid,
  79                     int flag, void *cb_data)
  80 {
  81         struct ls_refs_data *data = cb_data;
  82         const char *refname_nons = strip_namespace(refname);
  83
  84         strbuf_reset(&data->buf);
  85
  86         if (ref_is_hidden(refname_nons, refname, &data->hidden_refs))
  87                 return 0;
  88
  89         if (!ref_match(&data->prefixes, refname_nons))
  90                 return 0;
  91
  92         if (oid)
  93                 strbuf_addf(&data->buf, "%s %s", oid_to_hex(oid), refname_nons);
  94         else
  95                 strbuf_addf(&data->buf, "unborn %s", refname_nons);
  96         if (data->symrefs && flag & REF_ISSYMREF) {
  97                 struct object_id unused;
  98                 const char *symref_target = resolve_ref_unsafe(refname, 0,
  99                                                                &unused,
 100                                                                &flag);
 101
 102                 if (!symref_target)
 103                         die("'%s' is a symref but it is not?", refname);
 104
 105                 strbuf_addf(&data->buf, " symref-target:%s",
 106                             strip_namespace(symref_target));
 107         }
 108
 109         if (data->peel && oid) {
 110                 struct object_id peeled;
 111                 if (!peel_iterated_oid(oid, &peeled))
 112                         strbuf_addf(&data->buf, " peeled:%s", oid_to_hex(&peeled));
 113         }
 114
 115         strbuf_addch(&data->buf, '\n');
 116         packet_fwrite(stdout, data->buf.buf, data->buf.len);
 117
 118         return 0;
 119 }
 120
 121 static void send_possibly_unborn_head(struct ls_refs_data *data)
 122 {
 123         struct strbuf namespaced = STRBUF_INIT;
 124         struct object_id oid;
 125         int flag;
 126         int oid_is_null;
 127
 128         strbuf_addf(&namespaced, "%sHEAD", get_git_namespace());
 129         if (!resolve_ref_unsafe(namespaced.buf, 0, &oid, &flag))
 130                 return; /* bad ref */
 131         oid_is_null = is_null_oid(&oid);
 132         if (!oid_is_null ||
 133             (data->unborn && data->symrefs && (flag & REF_ISSYMREF)))
 134                 send_ref(namespaced.buf, oid_is_null ? NULL : &oid, flag, data);
 135         strbuf_release(&namespaced);
 136 }
 137
 138 static int ls_refs_config(const char *var, const char *value,
 139                           const struct config_context *ctx UNUSED,
 140                           void *cb_data)
 141 {
 142         struct ls_refs_data *data = cb_data;
 143         /*
 144          * We only serve fetches over v2 for now, so respect only "uploadpack"
 145          * config. This may need to eventually be expanded to "receive", but we
 146          * don't yet know how that information will be passed to ls-refs.
 147          */
 148         return parse_hide_refs_config(var, value, "uploadpack", &data->hidden_refs);
 149 }
 150
 151 int ls_refs(struct repository *r, struct packet_reader *request)
 152 {
 153         struct ls_refs_data data;
 154
 155         memset(&data, 0, sizeof(data));
 156         strvec_init(&data.prefixes);
 157         strbuf_init(&data.buf, 0);
 158         strvec_init(&data.hidden_refs);
 159
 160         git_config(ls_refs_config, &data);
 161
 162         while (packet_reader_read(request) == PACKET_READ_NORMAL) {
 163                 const char *arg = request->line;
 164                 const char *out;
 165
 166                 if (!strcmp("peel", arg))
 167                         data.peel = 1;
 168                 else if (!strcmp("symrefs", arg))
 169                         data.symrefs = 1;
 170                 else if (skip_prefix(arg, "ref-prefix ", &out)) {
 171                         if (data.prefixes.nr < TOO_MANY_PREFIXES)
 172                                 strvec_push(&data.prefixes, out);
 173                 }
 174                 else if (!strcmp("unborn", arg))
 175                         data.unborn = !!unborn_config(r);
 176                 else
 177                         die(_("unexpected line: '%s'"), arg);
 178         }
 179
 180         if (request->status != PACKET_READ_FLUSH)
 181                 die(_("expected flush after ls-refs arguments"));
 182
 183         /*
 184          * If we saw too many prefixes, we must avoid using them at all; as
 185          * soon as we have any prefix, they are meant to form a comprehensive
 186          * list.
 187          */
 188         if (data.prefixes.nr >= TOO_MANY_PREFIXES)
 189                 strvec_clear(&data.prefixes);
 190
 191         send_possibly_unborn_head(&data);
 192         if (!data.prefixes.nr)
 193                 strvec_push(&data.prefixes, "");
 194         refs_for_each_fullref_in_prefixes(get_main_ref_store(r),
 195                                           get_git_namespace(), data.prefixes.v,
 196                                           hidden_refs_to_excludes(&data.hidden_refs),
 197                                           send_ref, &data);
 198         packet_fflush(stdout);
 199         strvec_clear(&data.prefixes);
 200         strbuf_release(&data.buf);
 201         strvec_clear(&data.hidden_refs);
 202         return 0;
 203 }
 204
 205 int ls_refs_advertise(struct repository *r, struct strbuf *value)
 206 {
 207         if (value && unborn_config(r) == UNBORN_ADVERTISE)
 208                 strbuf_addstr(value, "unborn");
 209
 210         return 1;
 211 }