From 3ce44330cca9dbc4314feebb27403ebc3175b6c2 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Mon, 28 Mar 2016 09:14:31 +0200
Subject: New variable architecture

---
 build2/variable.txx | 401 +++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 303 insertions(+), 98 deletions(-)

(limited to 'build2/variable.txx')

diff --git a/build2/variable.txx b/build2/variable.txx
index 7a0d53a..721e3c0 100644
--- a/build2/variable.txx
+++ b/build2/variable.txx
@@ -6,57 +6,232 @@
 
 namespace build2
 {
+  // value
+  //
+  template <typename T>
+  void
+  default_dtor (value& v)
+  {
+    v.as<T> ().~T ();
+  }
+
+  template <typename T>
+  void
+  default_copy_ctor (value& l, const value& r, bool m)
+  {
+    if (m)
+      new (&l.data_) T (move (const_cast<value&> (r).as<T> ()));
+    else
+      new (&l.data_) T (r.as<T> ());
+  }
+
+  template <typename T>
+  void
+  default_copy_assign (value& l, const value& r, bool m)
+  {
+    if (m)
+      l.as<T> () = move (const_cast<value&> (r).as<T> ());
+    else
+      l.as<T> () = r.as<T> ();
+  }
+
+  template <typename T, bool empty>
+  bool
+  simple_assign (value& v, names&& ns, const variable& var)
+  {
+    size_t n (ns.size ());
+
+    if (empty ? n <= 1 : n == 1)
+    {
+      try
+      {
+        return value_traits<T>::assign (
+          v,
+          (n == 0
+           ? T ()
+           : value_traits<T>::convert (move (ns.front ()), nullptr)));
+      }
+      catch (const invalid_argument&) {} // Fall through.
+    }
+
+    error << "invalid " << value_traits<T>::value_type.name
+          << " value '" << ns << "' in variable " << var.name;
+    throw failed ();
+  }
+
+  template <typename T, bool empty>
+  bool
+  simple_append (value& v, names&& ns, const variable& var)
+  {
+    size_t n (ns.size ());
+
+    if (empty ? n <= 1 : n == 1)
+    {
+      try
+      {
+        return value_traits<T>::append (
+          v,
+          (n == 0
+           ? T ()
+           : value_traits<T>::convert (move (ns.front ()), nullptr)));
+      }
+      catch (const invalid_argument&) {} // Fall through.
+    }
+
+    error << "invalid " << value_traits<T>::value_type.name
+          << " value '" << ns << "' in variable " << var.name;
+    throw failed ();
+  }
+
+  template <typename T, bool empty>
+  bool
+  simple_prepend (value& v, names&& ns, const variable& var)
+  {
+    size_t n (ns.size ());
+
+    if (empty ? n <= 1 : n == 1)
+    {
+      try
+      {
+        return value_traits<T>::prepend (
+          v,
+          (n == 0
+           ? T ()
+           : value_traits<T>::convert (move (ns.front ()), nullptr)));
+      }
+      catch (const invalid_argument&) {} // Fall through.
+    }
+
+    error << "invalid " << value_traits<T>::value_type.name
+          << " value '" << ns << "' in variable " << var.name;
+    throw failed ();
+  }
+
+  template <typename T>
+  names_view
+  simple_reverse (const value& v, names& s)
+  {
+    s.emplace_back (value_traits<T>::reverse (v.as<T> ()));
+    return s;
+  }
+
+  template <typename T>
+  int
+  simple_compare (const value& l, const value& r)
+  {
+    return value_traits<T>::compare (l.as<T> (), r.as<T> ());
+  }
+
   // vector<T> value
   //
+
   template <typename T>
   bool
-  vector_assign (names& v, const variable& var)
+  vector_append (value& v, names&& ns, const variable& var)
   {
-    // Verify each element has valid value of T. Merge pairs.
+    vector<T>* p (v.null ()
+                  ? new (&v.data_) vector<T> ()
+                  : &v.as<vector<T>> ());
+
+    // Convert each element to T while merging pairs.
     //
-    for (auto i (v.begin ()); i != v.end (); )
+    for (auto i (ns.begin ()); i != ns.end (); ++i)
     {
       name& n (*i);
+      name* r (n.pair ? &*++i : nullptr);
 
-      if (n.pair)
+      try
       {
-        name& r (*++i);
-
-        if (!assign<T> (n, r))
-          fail << "invalid " << value_traits<T>::value_type.name
-               << " pair '" << n << "'@'" << r << "'"
-               << " in variable '" << var.name << "'";
-
-        i = v.erase (i);
+        p->push_back (value_traits<T>::convert (move (n), r));
       }
-      else
+      catch (const invalid_argument&)
       {
-        if (!assign<T> (n))
-          fail << "invalid " << value_traits<T>::value_type.name
-               << " element '" << n << "' in variable '" << var.name << "'";
-        ++i;
+        diag_record dr (fail);
+
+        dr << "invalid " << value_traits<T>::value_type.name;
+
+        if (n.pair)
+          dr << " element pair '" << n << "'@'" << *r << "'";
+        else
+          dr << " element '" << n << "'";
+
+        dr << " in variable " << var.name;
       }
     }
 
-    return !v.empty ();
+    return !p->empty ();
   }
 
   template <typename T>
   bool
-  vector_append (names& v, names a, const variable& var)
+  vector_assign (value& v, names&& ns, const variable& var)
   {
-    // Verify that what we are appending is valid.
+    if (!v.null ())
+      v.as<vector<T>> ().clear ();
+
+    return vector_append<T> (v, move (ns), var);
+  }
+
+  template <typename T>
+  bool
+  vector_prepend (value& v, names&& ns, const variable& var)
+  {
+    // Reduce to append.
     //
-    vector_assign<T> (a, var);
+    vector<T> t;
+    vector<T>* p;
 
-    if (v.empty ())
-      v = move (a);
+    if (v.null ())
+      p = new (&v.data_) vector<T> ();
     else
-      v.insert (v.end (),
-                make_move_iterator (a.begin ()),
-                make_move_iterator (a.end ()));
+    {
+      p = &v.as<vector<T>> ();
+      p->swap (t);
+    }
+
+    vector_append<T> (v, move (ns), var);
+
+    p->insert (p->end (),
+               make_move_iterator (t.begin ()),
+               make_move_iterator (t.end ()));
+
+    return !p->empty ();
+  }
+
+  template <typename T>
+  static names_view
+  vector_reverse (const value& v, names& s)
+  {
+    auto& vv (v.as<vector<T>> ());
+    s.reserve (vv.size ());
 
-    return !v.empty ();
+    for (const T& x: vv)
+      s.push_back (value_traits<T>::reverse (x));
+
+    return s;
+  }
+
+  template <typename T>
+  static int
+  vector_compare (const value& l, const value& r)
+  {
+    auto& lv (l.as<vector<T>> ());
+    auto& rv (r.as<vector<T>> ());
+
+    auto li (lv.begin ()), le (lv.end ());
+    auto ri (rv.begin ()), re (rv.end ());
+
+    for (; li != le && ri != re; ++li, ++ri)
+      if (int r = value_traits<T>::compare (*li, *ri))
+        return r;
+
+    if (li == le && ri != re) // l shorter than r.
+      return -1;
+
+    if (ri == re && li != le) // r shorter than l.
+      return 1;
+
+    return 0;
   }
 
   template <typename T>
@@ -67,105 +242,127 @@ namespace build2
   const value_type value_traits<vector<T>>::value_type
   {
     value_traits<vector<T>>::type_name.c_str (),
+    sizeof (vector<T>),
+    &default_dtor<vector<T>>,
+    &default_copy_ctor<vector<T>>,
+    &default_copy_assign<vector<T>>,
     &vector_assign<T>,
-    &vector_append<T>
+    &vector_append<T>,
+    &vector_prepend<T>,
+    &vector_reverse<T>,
+    nullptr,                          // No cast (cast data_ directly).
+    &vector_compare<T>
   };
 
   // map<K, V> value
   //
-  template <typename K, typename V, typename D>
-  map_value<K, V, D>& map_value<K, V, D>::
-  assign (std::map<K, V> m)
+  template <typename K, typename V>
+  bool
+  map_append (value& v, names&& ns, const variable& var)
   {
-    d->clear ();
-    for (auto& p: m)
-    {
-      d->emplace_back (p.first); // Const, can't move.
-      d->back ().pair = true;
-      d->emplace_back (move (p.second));
-    }
+    using std::map;
 
-    return *this;
-  }
+    map<K, V>* p (v.null ()
+                  ? new (&v.data_) map<K, V> ()
+                  : &v.as<map<K, V>> ());
 
-  template <typename K, typename V, typename D>
-  auto map_value<K, V, D>::
-  find (const K& k) -> iterator
-  {
-    // @@ Scan backwards to handle duplicates.
+    // Verify we have a sequence of pairs and convert each lhs/rhs to K/V.
     //
-    for (auto i (d->rbegin ()); i != d->rend (); ++i)
-      if (as<K> (*++i) == k)
-        return iterator (--(i.base ()));
+    for (auto i (ns.begin ()); i != ns.end (); ++i)
+    {
+      name& l (*i);
 
-    return end ();
-  }
+      if (!l.pair)
+        fail << value_traits<map<K, V>>::value_type.name << " key-value "
+             << "pair expected instead of '" << l << "' "
+             << "in variable " << var.name;
 
-  template <typename K, typename V, typename D>
-  auto map_value<K, V, D>::
-  find (const K& k) const -> const_iterator
-  {
-    // @@ Scan backwards to handle duplicates.
-    //
-    for (auto i (d->rbegin ()); i != d->rend (); ++i)
-      if (as<K> (*++i) == k)
-        return const_iterator (--(i.base ()));
+      name& r (*++i); // Got to have the second half of the pair.
+
+      try
+      {
+        K k (value_traits<K>::convert (move (l), nullptr));
+
+        try
+        {
+          V v (value_traits<V>::convert (move (r), nullptr));
 
-    return end ();
+          p->emplace (move (k), move (v));
+        }
+        catch (const invalid_argument&)
+        {
+          fail << "invalid " << value_traits<V>::value_type.name
+               << " element value '" << r << "' in variable " << var.name;
+        }
+      }
+      catch (const invalid_argument&)
+      {
+        fail << "invalid " << value_traits<K>::value_type.name
+             << " element key '" << l << "' in variable " << var.name;
+      }
+    }
+
+    return !p->empty ();
   }
 
   template <typename K, typename V>
   bool
-  map_assign (names& v, const variable& var)
+  map_assign (value& v, names&& ns, const variable& var)
   {
-    // Verify we have a sequence of pairs and each lhs/rhs is a valid
-    // value of K/V.
-    //
-    for (auto i (v.begin ()); i != v.end (); ++i)
-    {
-      if (!i->pair)
-        fail << value_traits<std::map<K, V>>::value_type.name << " key-value "
-             << "pair expected instead of '" << *i << "' "
-             << "in variable '" << var.name << "'";
+    using std::map;
 
-      if (!assign<K> (*i))
-        fail << "invalid " << value_traits<K>::value_type.name << " key "
-             << "'" << *i << "' in variable '" << var.name << "'";
+    if (!v.null ())
+      v.as<map<K, V>> ().clear ();
 
-      ++i; // Got to have the second half of the pair.
+    return map_append<K, V> (v, move (ns), var);
+  }
 
-      if (!assign<V> (*i))
-        fail << "invalid " << value_traits<V>::value_type.name << " value "
-             << "'" << *i << "' in variable '" << var.name << "'";
-    }
+  template <typename K, typename V>
+  static names_view
+  map_reverse (const value& v, names& s)
+  {
+    using std::map;
 
-    //@@ When doing sorting, note that assign() can convert the
-    //   value.
+    auto& vm (v.as<map<K, V>> ());
+    s.reserve (2 * vm.size ());
 
-    //@@ Is sorting really the right trade-off (i.e., insertion
-    //   vs search)? Perhaps linear search is ok?
+    for (const auto& p: vm)
+    {
+      s.push_back (value_traits<K>::reverse (p.first));
+      s.back ().pair = true;
+      s.push_back (value_traits<V>::reverse (p.second));
+    }
 
-    return !v.empty ();
+    return s;
   }
 
   template <typename K, typename V>
-  bool
-  map_append (names& v, names a, const variable& var)
+  static int
+  map_compare (const value& l, const value& r)
   {
-    //@@ Not weeding out duplicates.
+    using std::map;
 
-    // Verify that what we are appending is valid.
-    //
-    map_assign<K, V> (a, var);
+    auto& lm (l.as<map<K, V>> ());
+    auto& rm (r.as<map<K, V>> ());
 
-    if (v.empty ())
-      v = move (a);
-    else
-      v.insert (v.end (),
-                make_move_iterator (a.begin ()),
-                make_move_iterator (a.end ()));
+    auto li (lm.begin ()), le (lm.end ());
+    auto ri (rm.begin ()), re (rm.end ());
+
+    for (; li != le && ri != re; ++li, ++ri)
+    {
+      int r;
+      if ((r = value_traits<K>::compare (li->first, ri->first)) != 0 ||
+          (r = value_traits<V>::compare (li->second, ri->second)) != 0)
+        return r;
+    }
+
+    if (li == le && ri != re) // l shorter than r.
+      return -1;
+
+    if (ri == re && li != le) // r shorter than l.
+      return 1;
 
-    return !v.empty ();
+    return 0;
   }
 
   template <typename K, typename V>
@@ -176,8 +373,16 @@ namespace build2
   template <typename K, typename V>
   const value_type value_traits<std::map<K, V>>::value_type
   {
-    value_traits<std::map<K, V>>::type_name.c_str (),
+    value_traits<map<K, V>>::type_name.c_str (),
+    sizeof (map<K, V>),
+    &default_dtor<map<K, V>>,
+    &default_copy_ctor<map<K, V>>,
+    &default_copy_assign<map<K, V>>,
     &map_assign<K, V>,
-    &map_append<K, V>
+    &map_append<K, V>,
+    &map_append<K, V>,   // Prepend is the same as append.
+    &map_reverse<K, V>,
+    nullptr,             // No cast (cast data_ directly).
+    &map_compare<K, V>
   };
 }
-- 
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