negotiator/default.c

   1 #include "cache.h"
   2 #include "default.h"
   3 #include "../commit.h"
   4 #include "../fetch-negotiator.h"
   5 #include "../prio-queue.h"
   6 #include "../refs.h"
   7 #include "../tag.h"
   8
   9 /* Remember to update object flag allocation in object.h */
  10 #define COMMON          (1U << 2)
  11 #define COMMON_REF      (1U << 3)
  12 #define SEEN            (1U << 4)
  13 #define POPPED          (1U << 5)
  14
  15 static int marked;
  16
  17 struct negotiation_state {
  18         struct prio_queue rev_list;
  19         int non_common_revs;
  20 };
  21
  22 static void rev_list_push(struct negotiation_state *ns,
  23                           struct commit *commit, int mark)
  24 {
  25         if (!(commit->object.flags & mark)) {
  26                 commit->object.flags |= mark;
  27
  28                 if (parse_commit(commit))
  29                         return;
  30
  31                 prio_queue_put(&ns->rev_list, commit);
  32
  33                 if (!(commit->object.flags & COMMON))
  34                         ns->non_common_revs++;
  35         }
  36 }
  37
  38 static int clear_marks(const char *refname, const struct object_id *oid,
  39                        int flag, void *cb_data)
  40 {
  41         struct object *o = deref_tag(the_repository, parse_object(the_repository, oid), refname, 0);
  42
  43         if (o && o->type == OBJ_COMMIT)
  44                 clear_commit_marks((struct commit *)o,
  45                                    COMMON | COMMON_REF | SEEN | POPPED);
  46         return 0;
  47 }
  48
  49 /*
  50  * This function marks a rev and its ancestors as common.
  51  * In some cases, it is desirable to mark only the ancestors (for example
  52  * when only the server does not yet know that they are common).
  53  */
  54 static void mark_common(struct negotiation_state *ns, struct commit *commit,
  55                 int ancestors_only, int dont_parse)
  56 {
  57         if (commit != NULL && !(commit->object.flags & COMMON)) {
  58                 struct object *o = (struct object *)commit;
  59
  60                 if (!ancestors_only)
  61                         o->flags |= COMMON;
  62
  63                 if (!(o->flags & SEEN))
  64                         rev_list_push(ns, commit, SEEN);
  65                 else {
  66                         struct commit_list *parents;
  67
  68                         if (!ancestors_only && !(o->flags & POPPED))
  69                                 ns->non_common_revs--;
  70                         if (!o->parsed && !dont_parse)
  71                                 if (parse_commit(commit))
  72                                         return;
  73
  74                         for (parents = commit->parents;
  75                                         parents;
  76                                         parents = parents->next)
  77                                 mark_common(ns, parents->item, 0,
  78                                             dont_parse);
  79                 }
  80         }
  81 }
  82
  83 /*
  84  * Get the next rev to send, ignoring the common.
  85  */
  86 static const struct object_id *get_rev(struct negotiation_state *ns)
  87 {
  88         struct commit *commit = NULL;
  89
  90         while (commit == NULL) {
  91                 unsigned int mark;
  92                 struct commit_list *parents;
  93
  94                 if (ns->rev_list.nr == 0 || ns->non_common_revs == 0)
  95                         return NULL;
  96
  97                 commit = prio_queue_get(&ns->rev_list);
  98                 parse_commit(commit);
  99                 parents = commit->parents;
 100
 101                 commit->object.flags |= POPPED;
 102                 if (!(commit->object.flags & COMMON))
 103                         ns->non_common_revs--;
 104
 105                 if (commit->object.flags & COMMON) {
 106                         /* do not send "have", and ignore ancestors */
 107                         commit = NULL;
 108                         mark = COMMON | SEEN;
 109                 } else if (commit->object.flags & COMMON_REF)
 110                         /* send "have", and ignore ancestors */
 111                         mark = COMMON | SEEN;
 112                 else
 113                         /* send "have", also for its ancestors */
 114                         mark = SEEN;
 115
 116                 while (parents) {
 117                         if (!(parents->item->object.flags & SEEN))
 118                                 rev_list_push(ns, parents->item, mark);
 119                         if (mark & COMMON)
 120                                 mark_common(ns, parents->item, 1, 0);
 121                         parents = parents->next;
 122                 }
 123         }
 124
 125         return &commit->object.oid;
 126 }
 127
 128 static void known_common(struct fetch_negotiator *n, struct commit *c)
 129 {
 130         if (!(c->object.flags & SEEN)) {
 131                 rev_list_push(n->data, c, COMMON_REF | SEEN);
 132                 mark_common(n->data, c, 1, 1);
 133         }
 134 }
 135
 136 static void add_tip(struct fetch_negotiator *n, struct commit *c)
 137 {
 138         n->known_common = NULL;
 139         rev_list_push(n->data, c, SEEN);
 140 }
 141
 142 static const struct object_id *next(struct fetch_negotiator *n)
 143 {
 144         n->known_common = NULL;
 145         n->add_tip = NULL;
 146         return get_rev(n->data);
 147 }
 148
 149 static int ack(struct fetch_negotiator *n, struct commit *c)
 150 {
 151         int known_to_be_common = !!(c->object.flags & COMMON);
 152         mark_common(n->data, c, 0, 1);
 153         return known_to_be_common;
 154 }
 155
 156 static void release(struct fetch_negotiator *n)
 157 {
 158         clear_prio_queue(&((struct negotiation_state *)n->data)->rev_list);
 159         FREE_AND_NULL(n->data);
 160 }
 161
 162 void default_negotiator_init(struct fetch_negotiator *negotiator)
 163 {
 164         struct negotiation_state *ns;
 165         negotiator->known_common = known_common;
 166         negotiator->add_tip = add_tip;
 167         negotiator->next = next;
 168         negotiator->ack = ack;
 169         negotiator->release = release;
 170         negotiator->data = ns = xcalloc(1, sizeof(*ns));
 171         ns->rev_list.compare = compare_commits_by_commit_date;
 172
 173         if (marked)
 174                 for_each_ref(clear_marks, NULL);
 175         marked = 1;
 176 }