void thread_build()

in src/annoylib.h [1260:1296]

• 31 lines of code
• 8 McCabe index (conditional complexity)

  void thread_build(int q, int thread_idx, ThreadedBuildPolicy& threaded_build_policy) {
    // Each thread needs its own seed, otherwise each thread would be building the same tree(s)
    Random _random(_seed + thread_idx);

    vector<S> thread_roots;
    while (1) {
      if (q == -1) {
        threaded_build_policy.lock_n_nodes();
        if (_n_nodes >= 2 * _n_items) {
          threaded_build_policy.unlock_n_nodes();
          break;
        }
        threaded_build_policy.unlock_n_nodes();
      } else {
        if (thread_roots.size() >= (size_t)q) {
          break;
        }
      }

      if (_verbose) annoylib_showUpdate("pass %zd...\n", thread_roots.size());

      vector<S> indices;
      threaded_build_policy.lock_shared_nodes();
      for (S i = 0; i < _n_items; i++) {
        if (_get(i)->n_descendants >= 1) { // Issue #223
          indices.push_back(i);
        }
      }
      threaded_build_policy.unlock_shared_nodes();

      thread_roots.push_back(_make_tree(indices, true, _random, threaded_build_policy));
    }

    threaded_build_policy.lock_roots();
    _roots.insert(_roots.end(), thread_roots.begin(), thread_roots.end());
    threaded_build_policy.unlock_roots();
  }