// file      : build/algorithm.ixx -*- C++ -*-
// copyright : Copyright (c) 2014-2015 Code Synthesis Tools CC
// license   : MIT; see accompanying LICENSE file

#include <build/prerequisite>
#include <build/context>

namespace build
{
  inline target&
  search (prerequisite& p)
  {
    if (p.target == nullptr)
      p.target = &search (
        prerequisite_key {&p.type, &p.dir, &p.name, &p.ext, &p.scope});

    return *p.target;
  }

  void
  match_impl (action, target&);

  inline void
  match (action a, target& t)
  {
    if (!t.recipe (a))
      match_impl (a, t);

    t.dependents++;
  }

  target_state
  execute_impl (action, target&);

  inline target_state
  execute (action a, target& t)
  {
    t.dependents--;

    switch (t.state)
    {
    case target_state::unchanged:
    case target_state::changed: return t.state;
    default:
      {
        // Handle the "last" execution mode.
        //
        if (current_mode == execution_mode::last && t.dependents != 0)
          return (t.state = target_state::postponed);

        return execute_impl (a, t);
      }
    }
  }

  template <typename T, executor_function* E>
  T*
  execute_find_prerequisites (action, target&, const timestamp&, bool&);

  template <typename T, executor_function* E>
  inline T*
  execute_find_prerequisites (action a, target& t, const timestamp& mt)
  {
    bool e (mt == timestamp_nonexistent);
    T* r (execute_find_prerequisites<T, E> (a, t, mt, e));
    assert (r != nullptr);
    return e ? r : nullptr;
  }
}