ls-refs.c

   1 #define USE_THE_REPOSITORY_VARIABLE
   2
   3 #include "git-compat-util.h"
   4 #include "environment.h"
   5 #include "gettext.h"
   6 #include "hash.h"
   7 #include "hex.h"
   8 #include "repository.h"
   9 #include "refs.h"
  10 #include "strvec.h"
  11 #include "ls-refs.h"
  12 #include "pkt-line.h"
  13 #include "config.h"
  14 #include "string-list.h"
  15
  16 static enum {
  17         UNBORN_IGNORE = 0,
  18         UNBORN_ALLOW,
  19         UNBORN_ADVERTISE /* implies ALLOW */
  20 } unborn_config(struct repository *r)
  21 {
  22         const char *str = NULL;
  23
  24         if (repo_config_get_string_tmp(r, "lsrefs.unborn", &str)) {
  25                 /*
  26                  * If there is no such config, advertise and allow it by
  27                  * default.
  28                  */
  29                 return UNBORN_ADVERTISE;
  30         } else {
  31                 if (!strcmp(str, "advertise")) {
  32                         return UNBORN_ADVERTISE;
  33                 } else if (!strcmp(str, "allow")) {
  34                         return UNBORN_ALLOW;
  35                 } else if (!strcmp(str, "ignore")) {
  36                         return UNBORN_IGNORE;
  37                 } else {
  38                         die(_("invalid value for '%s': '%s'"),
  39                             "lsrefs.unborn", str);
  40                 }
  41         }
  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         struct strvec hidden_refs;
  77         unsigned unborn : 1;
  78 };
  79
  80 static int send_ref(const char *refname, const char *referent UNUSED, const struct object_id *oid,
  81                     int flag, void *cb_data)
  82 {
  83         struct ls_refs_data *data = cb_data;
  84         const char *refname_nons = strip_namespace(refname);
  85
  86         strbuf_reset(&data->buf);
  87
  88         if (ref_is_hidden(refname_nons, refname, &data->hidden_refs))
  89                 return 0;
  90
  91         if (!ref_match(&data->prefixes, refname_nons))
  92                 return 0;
  93
  94         if (oid)
  95                 strbuf_addf(&data->buf, "%s %s", oid_to_hex(oid), refname_nons);
  96         else
  97                 strbuf_addf(&data->buf, "unborn %s", refname_nons);
  98         if (data->symrefs && flag & REF_ISSYMREF) {
  99                 struct object_id unused;
 100                 const char *symref_target = refs_resolve_ref_unsafe(get_main_ref_store(the_repository),
 101                                                                     refname,
 102                                                                     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(the_repository, 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 (!refs_resolve_ref_unsafe(get_main_ref_store(the_repository), 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, NULL, 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                           const struct config_context *ctx UNUSED,
 144                           void *cb_data)
 145 {
 146         struct ls_refs_data *data = cb_data;
 147         /*
 148          * We only serve fetches over v2 for now, so respect only "uploadpack"
 149          * config. This may need to eventually be expanded to "receive", but we
 150          * don't yet know how that information will be passed to ls-refs.
 151          */
 152         return parse_hide_refs_config(var, value, "uploadpack", &data->hidden_refs);
 153 }
 154
 155 int ls_refs(struct repository *r, struct packet_reader *request)
 156 {
 157         struct ls_refs_data data;
 158
 159         memset(&data, 0, sizeof(data));
 160         strvec_init(&data.prefixes);
 161         strbuf_init(&data.buf, 0);
 162         strvec_init(&data.hidden_refs);
 163
 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 = !!unborn_config(r);
 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                                           hidden_refs_to_excludes(&data.hidden_refs),
 201                                           send_ref, &data);
 202         packet_fflush(stdout);
 203         strvec_clear(&data.prefixes);
 204         strbuf_release(&data.buf);
 205         strvec_clear(&data.hidden_refs);
 206         return 0;
 207 }
 208
 209 int ls_refs_advertise(struct repository *r, struct strbuf *value)
 210 {
 211         if (value && unborn_config(r) == UNBORN_ADVERTISE)
 212                 strbuf_addstr(value, "unborn");
 213
 214         return 1;
 215 }