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-rw-r--r--notes-merge.c120
1 files changed, 120 insertions, 0 deletions
diff --git a/notes-merge.c b/notes-merge.c
new file mode 100644
index 0000000..ab98850
--- /dev/null
+++ b/notes-merge.c
@@ -0,0 +1,120 @@
+#include "cache.h"
+#include "commit.h"
+#include "refs.h"
+#include "notes-merge.h"
+
+void init_notes_merge_options(struct notes_merge_options *o)
+{
+ memset(o, 0, sizeof(struct notes_merge_options));
+ o->verbosity = NOTES_MERGE_VERBOSITY_DEFAULT;
+}
+
+#define OUTPUT(o, v, ...) \
+ do { \
+ if ((o)->verbosity >= (v)) { \
+ printf(__VA_ARGS__); \
+ puts(""); \
+ } \
+ } while (0)
+
+int notes_merge(struct notes_merge_options *o,
+ unsigned char *result_sha1)
+{
+ unsigned char local_sha1[20], remote_sha1[20];
+ struct commit *local, *remote;
+ struct commit_list *bases = NULL;
+ const unsigned char *base_sha1;
+ int result = 0;
+
+ assert(o->local_ref && o->remote_ref);
+ hashclr(result_sha1);
+
+ trace_printf("notes_merge(o->local_ref = %s, o->remote_ref = %s)\n",
+ o->local_ref, o->remote_ref);
+
+ /* Dereference o->local_ref into local_sha1 */
+ if (!resolve_ref(o->local_ref, local_sha1, 0, NULL))
+ die("Failed to resolve local notes ref '%s'", o->local_ref);
+ else if (!check_ref_format(o->local_ref) && is_null_sha1(local_sha1))
+ local = NULL; /* local_sha1 == null_sha1 indicates unborn ref */
+ else if (!(local = lookup_commit_reference(local_sha1)))
+ die("Could not parse local commit %s (%s)",
+ sha1_to_hex(local_sha1), o->local_ref);
+ trace_printf("\tlocal commit: %.7s\n", sha1_to_hex(local_sha1));
+
+ /* Dereference o->remote_ref into remote_sha1 */
+ if (get_sha1(o->remote_ref, remote_sha1)) {
+ /*
+ * Failed to get remote_sha1. If o->remote_ref looks like an
+ * unborn ref, perform the merge using an empty notes tree.
+ */
+ if (!check_ref_format(o->remote_ref)) {
+ hashclr(remote_sha1);
+ remote = NULL;
+ } else {
+ die("Failed to resolve remote notes ref '%s'",
+ o->remote_ref);
+ }
+ } else if (!(remote = lookup_commit_reference(remote_sha1))) {
+ die("Could not parse remote commit %s (%s)",
+ sha1_to_hex(remote_sha1), o->remote_ref);
+ }
+ trace_printf("\tremote commit: %.7s\n", sha1_to_hex(remote_sha1));
+
+ if (!local && !remote)
+ die("Cannot merge empty notes ref (%s) into empty notes ref "
+ "(%s)", o->remote_ref, o->local_ref);
+ if (!local) {
+ /* result == remote commit */
+ hashcpy(result_sha1, remote_sha1);
+ goto found_result;
+ }
+ if (!remote) {
+ /* result == local commit */
+ hashcpy(result_sha1, local_sha1);
+ goto found_result;
+ }
+ assert(local && remote);
+
+ /* Find merge bases */
+ bases = get_merge_bases(local, remote, 1);
+ if (!bases) {
+ base_sha1 = null_sha1;
+ OUTPUT(o, 4, "No merge base found; doing history-less merge");
+ } else if (!bases->next) {
+ base_sha1 = bases->item->object.sha1;
+ OUTPUT(o, 4, "One merge base found (%.7s)",
+ sha1_to_hex(base_sha1));
+ } else {
+ /* TODO: How to handle multiple merge-bases? */
+ base_sha1 = bases->item->object.sha1;
+ OUTPUT(o, 3, "Multiple merge bases found. Using the first "
+ "(%.7s)", sha1_to_hex(base_sha1));
+ }
+
+ OUTPUT(o, 4, "Merging remote commit %.7s into local commit %.7s with "
+ "merge-base %.7s", sha1_to_hex(remote->object.sha1),
+ sha1_to_hex(local->object.sha1), sha1_to_hex(base_sha1));
+
+ if (!hashcmp(remote->object.sha1, base_sha1)) {
+ /* Already merged; result == local commit */
+ OUTPUT(o, 2, "Already up-to-date!");
+ hashcpy(result_sha1, local->object.sha1);
+ goto found_result;
+ }
+ if (!hashcmp(local->object.sha1, base_sha1)) {
+ /* Fast-forward; result == remote commit */
+ OUTPUT(o, 2, "Fast-forward");
+ hashcpy(result_sha1, remote->object.sha1);
+ goto found_result;
+ }
+
+ /* TODO: */
+ result = error("notes_merge() cannot yet handle real merges.");
+
+found_result:
+ free_commit_list(bases);
+ trace_printf("notes_merge(): result = %i, result_sha1 = %.7s\n",
+ result, sha1_to_hex(result_sha1));
+ return result;
+}