notes-merge.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "refs.h"
   4 #include "notes.h"
   5 #include "notes-merge.h"
   6
   7 void init_notes_merge_options(struct notes_merge_options *o)
   8 {
   9         memset(o, 0, sizeof(struct notes_merge_options));
  10         o->verbosity = NOTES_MERGE_VERBOSITY_DEFAULT;
  11 }
  12
  13 #define OUTPUT(o, v, ...) \
  14         do { \
  15                 if ((o)->verbosity >= (v)) { \
  16                         printf(__VA_ARGS__); \
  17                         puts(""); \
  18                 } \
  19         } while (0)
  20
  21 void create_notes_commit(struct notes_tree *t, struct commit_list *parents,
  22                          const char *msg, unsigned char *result_sha1)
  23 {
  24         unsigned char tree_sha1[20];
  25
  26         assert(t->initialized);
  27
  28         if (write_notes_tree(t, tree_sha1))
  29                 die("Failed to write notes tree to database");
  30
  31         if (!parents) {
  32                 /* Deduce parent commit from t->ref */
  33                 unsigned char parent_sha1[20];
  34                 if (!read_ref(t->ref, parent_sha1)) {
  35                         struct commit *parent = lookup_commit(parent_sha1);
  36                         if (!parent || parse_commit(parent))
  37                                 die("Failed to find/parse commit %s", t->ref);
  38                         commit_list_insert(parent, &parents);
  39                 }
  40                 /* else: t->ref points to nothing, assume root/orphan commit */
  41         }
  42
  43         if (commit_tree(msg, tree_sha1, parents, result_sha1, NULL))
  44                 die("Failed to commit notes tree to database");
  45 }
  46
  47 int notes_merge(struct notes_merge_options *o,
  48                 unsigned char *result_sha1)
  49 {
  50         unsigned char local_sha1[20], remote_sha1[20];
  51         struct commit *local, *remote;
  52         struct commit_list *bases = NULL;
  53         const unsigned char *base_sha1;
  54         int result = 0;
  55
  56         assert(o->local_ref && o->remote_ref);
  57         hashclr(result_sha1);
  58
  59         trace_printf("notes_merge(o->local_ref = %s, o->remote_ref = %s)\n",
  60                o->local_ref, o->remote_ref);
  61
  62         /* Dereference o->local_ref into local_sha1 */
  63         if (!resolve_ref(o->local_ref, local_sha1, 0, NULL))
  64                 die("Failed to resolve local notes ref '%s'", o->local_ref);
  65         else if (!check_ref_format(o->local_ref) && is_null_sha1(local_sha1))
  66                 local = NULL; /* local_sha1 == null_sha1 indicates unborn ref */
  67         else if (!(local = lookup_commit_reference(local_sha1)))
  68                 die("Could not parse local commit %s (%s)",
  69                     sha1_to_hex(local_sha1), o->local_ref);
  70         trace_printf("\tlocal commit: %.7s\n", sha1_to_hex(local_sha1));
  71
  72         /* Dereference o->remote_ref into remote_sha1 */
  73         if (get_sha1(o->remote_ref, remote_sha1)) {
  74                 /*
  75                  * Failed to get remote_sha1. If o->remote_ref looks like an
  76                  * unborn ref, perform the merge using an empty notes tree.
  77                  */
  78                 if (!check_ref_format(o->remote_ref)) {
  79                         hashclr(remote_sha1);
  80                         remote = NULL;
  81                 } else {
  82                         die("Failed to resolve remote notes ref '%s'",
  83                             o->remote_ref);
  84                 }
  85         } else if (!(remote = lookup_commit_reference(remote_sha1))) {
  86                 die("Could not parse remote commit %s (%s)",
  87                     sha1_to_hex(remote_sha1), o->remote_ref);
  88         }
  89         trace_printf("\tremote commit: %.7s\n", sha1_to_hex(remote_sha1));
  90
  91         if (!local && !remote)
  92                 die("Cannot merge empty notes ref (%s) into empty notes ref "
  93                     "(%s)", o->remote_ref, o->local_ref);
  94         if (!local) {
  95                 /* result == remote commit */
  96                 hashcpy(result_sha1, remote_sha1);
  97                 goto found_result;
  98         }
  99         if (!remote) {
 100                 /* result == local commit */
 101                 hashcpy(result_sha1, local_sha1);
 102                 goto found_result;
 103         }
 104         assert(local && remote);
 105
 106         /* Find merge bases */
 107         bases = get_merge_bases(local, remote, 1);
 108         if (!bases) {
 109                 base_sha1 = null_sha1;
 110                 OUTPUT(o, 4, "No merge base found; doing history-less merge");
 111         } else if (!bases->next) {
 112                 base_sha1 = bases->item->object.sha1;
 113                 OUTPUT(o, 4, "One merge base found (%.7s)",
 114                        sha1_to_hex(base_sha1));
 115         } else {
 116                 /* TODO: How to handle multiple merge-bases? */
 117                 base_sha1 = bases->item->object.sha1;
 118                 OUTPUT(o, 3, "Multiple merge bases found. Using the first "
 119                        "(%.7s)", sha1_to_hex(base_sha1));
 120         }
 121
 122         OUTPUT(o, 4, "Merging remote commit %.7s into local commit %.7s with "
 123                "merge-base %.7s", sha1_to_hex(remote->object.sha1),
 124                sha1_to_hex(local->object.sha1), sha1_to_hex(base_sha1));
 125
 126         if (!hashcmp(remote->object.sha1, base_sha1)) {
 127                 /* Already merged; result == local commit */
 128                 OUTPUT(o, 2, "Already up-to-date!");
 129                 hashcpy(result_sha1, local->object.sha1);
 130                 goto found_result;
 131         }
 132         if (!hashcmp(local->object.sha1, base_sha1)) {
 133                 /* Fast-forward; result == remote commit */
 134                 OUTPUT(o, 2, "Fast-forward");
 135                 hashcpy(result_sha1, remote->object.sha1);
 136                 goto found_result;
 137         }
 138
 139         /* TODO: */
 140         result = error("notes_merge() cannot yet handle real merges.");
 141
 142 found_result:
 143         free_commit_list(bases);
 144         trace_printf("notes_merge(): result = %i, result_sha1 = %.7s\n",
 145                result, sha1_to_hex(result_sha1));
 146         return result;
 147 }