+ } else
+ /* We should never create a dependency from middle of
+ * a transaction. */
+ assert(!in_transaction(op[satisfies_file], satisfies_opnum)
+ || op[satisfies_file][satisfies_opnum].op
+ == OP_TDB_TRANSACTION_COMMIT
+ || op[satisfies_file][satisfies_opnum].op
+ == OP_TDB_TRANSACTION_CANCEL);
+
+ assert(op[needs_file][needs_opnum].op != OP_TDB_TRAVERSE);
+ assert(op[satisfies_file][satisfies_opnum].op != OP_TDB_TRAVERSE);
+
+ dep = talloc(ctx, struct depend);
+ dep->needs_file = needs_file;
+ dep->needs_opnum = needs_opnum;
+ dep->satisfies_file = satisfies_file;
+ dep->satisfies_opnum = satisfies_opnum;
+ list_add(&op[satisfies_file][satisfies_opnum].post, &dep->post_list);
+ list_add(&op[needs_file][needs_opnum].pre, &dep->pre_list);
+ talloc_set_destructor(dep, destroy_depend);
+}
+
+static bool changes_db(const TDB_DATA *key, const struct op *op)
+{
+ return gives(key, NULL, op) != NULL;
+}
+
+static void depend_on_previous(struct op *op[],
+ char *filename[],
+ unsigned int num,
+ struct key_user user[],
+ unsigned int i,
+ int prev)
+{
+ bool deps[num];
+ int j;
+
+ if (i == 0)
+ return;
+
+ if (prev == i - 1) {
+ /* Just depend on previous. */
+ add_dependency(NULL, op, filename,
+ user[i].file, user[i].op_num,
+ user[prev].file, user[prev].op_num);
+ return;
+ }
+
+ /* We have to wait for the readers. Find last one in *each* file. */
+ memset(deps, 0, sizeof(deps));
+ deps[user[i].file] = true;
+ for (j = i - 1; j > prev; j--) {
+ if (!deps[user[j].file]) {
+ add_dependency(NULL, op, filename,
+ user[i].file, user[i].op_num,
+ user[j].file, user[j].op_num);
+ deps[user[j].file] = true;
+ }
+ }
+}
+
+/* This is simple, but not complete. We don't take into account
+ * indirect dependencies. */
+static void optimize_dependencies(struct op *op[], unsigned int num_ops[],
+ unsigned int num)
+{
+ unsigned int i, j;
+
+ /* There can only be one real dependency on each file */
+ for (i = 0; i < num; i++) {
+ for (j = 1; j < num_ops[i]; j++) {
+ struct depend *dep, *next;
+ struct depend *prev[num];
+
+ memset(prev, 0, sizeof(prev));
+
+ list_for_each_safe(&op[i][j].pre, dep, next, pre_list) {
+ if (!prev[dep->satisfies_file]) {
+ prev[dep->satisfies_file] = dep;
+ continue;
+ }
+ if (prev[dep->satisfies_file]->satisfies_opnum
+ < dep->satisfies_opnum) {
+ talloc_free(prev[dep->satisfies_file]);
+ prev[dep->satisfies_file] = dep;
+ } else
+ talloc_free(dep);
+ }