Function eval_condition

src/cypher/cypher.c:2405–2477

Evaluate a WHERE condition against a binding */

/* Evaluate a WHERE condition against a binding */
static bool eval_condition(const cbm_condition_t *c, binding_t *b) {
    /* Label test: WHERE n:Label (#241) — compare the bound node's label
     * directly rather than a property value. */
    if (strcmp(c->op, "HAS_LABEL") == 0) {
        cbm_node_t *n = binding_get(b, c->variable);
        bool result = n && n->label && c->value && strcmp(n->label, c->value) == 0;
        return c->negated ? !result : result;
    }

    /* EXISTS { (var)-[:TYPE]->() }: does the bound node have any edge of the
     * given type in the requested direction? (dir 0=out, 1=in, 2=any) */
    if (strcmp(c->op, "EXISTS") == 0) {
        cbm_node_t *n = binding_get(b, c->variable);
        bool result = false;
        if (n && b->store) {
            cbm_edge_t *edges = NULL;
            int cnt = 0;
            if (c->exists_dir != 1) { /* outbound or any */
                if (c->value) {
                    cbm_store_find_edges_by_source_type(b->store, n->id, c->value, &edges, &cnt);
                } else {
                    cbm_store_find_edges_by_source(b->store, n->id, &edges, &cnt);
                }
                result = cnt > 0;
                cbm_store_free_edges(edges, cnt);
            }
            if (!result && c->exists_dir != 0) { /* inbound or any */
                edges = NULL;
                cnt = 0;
                if (c->value) {
                    cbm_store_find_edges_by_target_type(b->store, n->id, c->value, &edges, &cnt);
                } else {
                    cbm_store_find_edges_by_target(b->store, n->id, &edges, &cnt);
                }
                result = cnt > 0;
                cbm_store_free_edges(edges, cnt);
            }
        }
        return c->negated ? !result : result;
    }

    const char *actual = resolve_condition_value(c, b);
    if (!actual) {
        return true;
    }

    bool result;

    /* IS NULL / IS NOT NULL */
    if (strcmp(c->op, "IS NULL") == 0) {
        result = (actual[0] == '\0');
        return c->negated ? !result : result;
    }
    if (strcmp(c->op, "IS NOT NULL") == 0) {
        result = (actual[0] != '\0');
        return c->negated ? !result : result;
    }