From 9fb791e9fad6c63fc1dac49f4d05ae63b8a3db9b Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 5 Jan 2016 11:55:15 +0200
Subject: Rename build directory/namespace to build2

---
 build2/variable | 831 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 831 insertions(+)
 create mode 100644 build2/variable

(limited to 'build2/variable')

diff --git a/build2/variable b/build2/variable
new file mode 100644
index 0000000..6304979
--- /dev/null
+++ b/build2/variable
@@ -0,0 +1,831 @@
+// file      : build2/variable -*- C++ -*-
+// copyright : Copyright (c) 2014-2015 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef BUILD2_VARIABLE
+#define BUILD2_VARIABLE
+
+#include <map>
+#include <vector>
+#include <cstddef>       // nullptr_t
+#include <utility>       // pair, make_pair()
+#include <iterator>
+#include <functional>    // hash
+#include <type_traits>   // conditional, is_reference, remove_reference, etc.
+#include <unordered_set>
+
+#include <butl/prefix-map>
+
+#include <build2/types>
+#include <build2/utility>
+
+#include <build2/target-type>
+
+namespace build2
+{
+  struct variable;
+
+  // If assign is NULL, then the value is assigned as is. If append
+  // is NULL, then the names are appended to the end of the value
+  // and assign is called, if not NULL. Variable is provided primarily
+  // for diagnostics. Return true if the resulting value is not empty.
+  //
+  struct value_type
+  {
+    const char* name;
+    bool (*const assign) (names&, const variable&);
+    bool (*const append) (names&, names, const variable&);
+  };
+
+  enum class variable_visibility
+  {
+    scope,    // This scope (no outer scopes).
+    project,  // This project (no outer projects).
+    normal    // All outer scopes.
+  };
+
+  // variable
+  //
+  // The two variables are considered the same if they have the same name.
+  //
+  struct variable
+  {
+    std::string name;
+    const value_type* type;         // If NULL, then not (yet) typed.
+    variable_visibility visibility;
+    char pairs;                     // Pair symbold or '\0' if not used.
+  };
+
+  inline bool
+  operator== (const variable& x, const variable& y) {return x.name == y.name;}
+
+  typedef std::reference_wrapper<const variable> variable_cref;
+
+  // value
+  //
+  class value
+  {
+  public:
+    // By default we create NULL value.
+    //
+    explicit value (const value_type* t = nullptr)
+        : type (t), state_ (state_type::null) {}
+
+    value (value&&) = default;
+
+    value&
+    operator= (std::nullptr_t)
+    {
+      data_.clear ();
+      state_ = state_type::null;
+      return *this;
+    }
+
+    value&
+    operator= (value&&);
+
+    value&
+    operator= (const value& v)
+    {
+      if (&v != this)
+        *this = value (v);
+      return *this;
+    }
+
+    value&
+    operator= (reference_wrapper<value> v) {return *this = v.get ();}
+
+    value&
+    operator= (reference_wrapper<const value> v) {return *this = v.get ();}
+
+    value&
+    append (value, const variable&); // Aka operator+=().
+
+    value&
+    prepend (value, const variable&); // Aka operator=+().
+
+    // Forwarded to the representation type's assign()/append() (see below).
+    //
+    template <typename T> value& operator= (T);
+    value& operator= (const char* v) {return *this = std::string (v);}
+
+    template <typename T> value& operator+= (T);
+    value& operator+= (const char* v) {return *this += std::string (v);}
+
+  private:
+    explicit value (const value&) = default;
+
+  public:
+    const value_type* type; // NULL means this value is not (yet) typed.
+
+    bool null () const {return state_ == state_type::null;}
+    bool empty () const {return state_ == state_type::empty;}
+
+    explicit operator bool () const {return !null ();}
+    bool operator== (std::nullptr_t) const {return null ();}
+    bool operator!= (std::nullptr_t) const {return !null ();}
+
+    // Raw data read interface.
+    //
+    using const_iterator = names::const_iterator;
+
+    const_iterator begin () const {return data_.begin ();}
+    const_iterator end () const {return data_.end ();}
+
+    // Raw data write interface. Note that it triggers callbacks for
+    // typed values. Variable is passed for diagnostics.
+    //
+    void
+    assign (names, const variable&);
+
+    void
+    append (names, const variable&);
+
+    void
+    prepend (names, const variable&);
+
+  public:
+    // Don't use directly except in the implementation of representation
+    // types, in which case take care to update state.
+    //
+    enum class state_type {null, empty, filled} state_;
+    names data_;
+  };
+
+  //@@ Right now we assume that for each value type each value has a
+  //   unique representation. This is currently not the case for map.
+  //
+  inline bool
+  operator== (const value& x, const value& y)
+  {
+    return x.state_ == y.state_ && x.data_ == y.data_;
+  }
+
+  inline bool
+  operator!= (const value& x, const value& y) {return !(x == y);}
+
+  // lookup
+  //
+  // A variable can be undefined, NULL, or contain a (potentially
+  // empty) value.
+  //
+  struct variable_map;
+
+  template <typename V>
+  struct lookup
+  {
+    V* value;
+    const variable_map* vars;
+
+    bool
+    defined () const {return value != nullptr;}
+
+    // Note: returns true if defined and not NULL.
+    //
+    explicit operator bool () const {return defined () && !value->null ();}
+
+    V& operator*  () const {return *value;}
+    V* operator-> () const {return value;}
+
+    // Return true if this value belongs to the specified scope or target.
+    // Note that it can also be a target type/pattern-specific value.
+    //
+    template <typename T>
+    bool
+    belongs (const T& x) const {return vars == &x.vars;}
+
+    lookup (): value (nullptr), vars (nullptr) {}
+    lookup (V* v, const variable_map* vs)
+        : value (v), vars (v != nullptr ? vs : nullptr) {}
+
+    template <typename T>
+    lookup (V& v, const T& x): lookup (&v, &x.vars) {}
+  };
+
+  // Representation types.
+  //
+  template <typename T> struct value_traits;
+
+  // Assign value type to the value.
+  //
+  template <typename T>
+  void assign (value&, const variable&);
+  void assign (value&, const value_type*, const variable&);
+
+  template <typename T> typename value_traits<T>::type as (value&);
+  template <typename T> typename value_traits<T>::const_type as (const value&);
+
+  // "Assign" simple value type to the value stored in name. Return false
+  // if the value is not valid for this type.
+  //
+  template <typename T> bool assign (name&);
+
+  template <typename T> typename value_traits<T>::type as (name&);
+  template <typename T> typename value_traits<T>::const_type as (const name&);
+
+  // bool
+  //
+  template <typename D>
+  struct bool_value
+  {
+    explicit
+    operator bool () const {return d->value[0] == 't';}
+
+    bool_value&
+    operator= (bool v)
+    {
+      d->value = v ? "true" : "false";
+      return *this;
+    }
+
+    bool_value&
+    operator+= (bool v)
+    {
+      if (!*this && v)
+        d->value = "true";
+      return *this;
+    }
+
+    // Implementation details.
+    //
+  public:
+    explicit bool_value (D& d): d (&d) {}
+
+    bool_value (const bool_value&) = delete;
+    bool_value& operator= (const bool_value&) = delete; // Rebind or deep?
+
+    bool_value (bool_value&&) = default;
+    bool_value& operator= (bool_value&&) = delete;
+
+    D* d; // name
+  };
+
+  template <>
+  struct value_traits<bool>
+  {
+    using type = bool_value<name>;
+    using const_type = bool_value<const name>;
+
+    static type       as (name& n) {return type (n);}
+    static const_type as (const name& n) {return const_type (n);}
+
+    static type       as (value&);
+    static const_type as (const value&);
+
+    static bool assign (name&);
+    static void assign (value&, bool);
+    static void append (value&, bool);
+
+    static const build2::value_type value_type;
+  };
+
+  extern const value_type* bool_type;
+
+  // string
+  //
+  template <>
+  struct value_traits<std::string>
+  {
+    using type = std::string&;
+    using const_type = const std::string&;
+
+    static type       as (name& n) {return n.value;}
+    static const_type as (const name& n) {return n.value;}
+
+    static type       as (value&);
+    static const_type as (const value&);
+
+    static bool assign (name&);
+    static void assign (value&, std::string);
+    static void append (value&, std::string);
+
+    static const build2::value_type value_type;
+  };
+
+  extern const value_type* string_type;
+
+  // dir_path
+  //
+  template <>
+  struct value_traits<dir_path>
+  {
+    using type = dir_path&;
+    using const_type = const dir_path&;
+
+    static type       as (name& n) {return n.dir;}
+    static const_type as (const name& n) {return n.dir;}
+
+    static type       as (value&);
+    static const_type as (const value&);
+
+    static bool assign (name&);
+    static void assign (value&, dir_path);
+    static void append (value&, dir_path);
+
+    static const build2::value_type value_type;
+  };
+
+  extern const value_type* dir_path_type;
+
+  // name
+  //
+  template <>
+  struct value_traits<name>
+  {
+    using type = name&;
+    using const_type = const name&;
+
+    static type       as (name& n) {return n;}
+    static const_type as (const name& n) {return n;}
+
+    static type       as (value&);
+    static const_type as (const value&);
+
+    static bool assign (name&) {return true;}
+    static void assign (value&, name);
+    static void append (value&, name) = delete;
+
+    static const build2::value_type value_type;
+  };
+
+  extern const value_type* name_type;
+
+  // vector<T>
+  //
+  template <typename T, typename D>
+  struct vector_value
+  {
+    using size_type = typename D::size_type;
+
+    using value_type = typename value_traits<T>::type;
+    using const_value_type = typename value_traits<T>::const_type;
+
+    template <typename I, typename V, typename R>
+    struct iterator_impl: I
+    {
+      using value_type = V;
+      using pointer = value_type*;
+      using reference = R;
+      using difference_type = typename I::difference_type;
+
+      iterator_impl () = default;
+      iterator_impl (const I& i): I (i) {}
+
+      // Note: operator->() is unavailable if R is a value.
+      //
+      reference operator* () const {return as<T> (I::operator* ());}
+      pointer operator-> () const {return &as<T> (I::operator* ());}
+      reference operator[] (difference_type n) const
+      {
+        return as<T> (I::operator[] (n));
+      }
+    };
+
+    // Make iterator the same as const_iterator if our data type is const.
+    //
+    using const_iterator =
+      iterator_impl<names::const_iterator, const T, const_value_type>;
+    using iterator = typename std::conditional<
+      std::is_const<D>::value,
+      const_iterator,
+      iterator_impl<names::iterator, T, value_type>>::type;
+
+  public:
+    vector_value&
+    operator= (std::vector<T> v) {assign (std::move (v)); return *this;}
+
+    vector_value&
+    assign (std::vector<T>);
+
+    template <typename D1>
+    vector_value&
+    assign (const vector_value<T, D1>&);
+
+    template <typename D1>
+    vector_value&
+    append (const vector_value<T, D1>&);
+
+  public:
+    bool empty () const {return d->empty ();}
+    size_type size () const {return d->size ();}
+
+    value_type operator[] (size_type i) {return as<T> ((*d)[i]);}
+    const_value_type operator[] (size_type i) const {return as<T> ((*d)[i]);}
+
+    iterator begin () {return iterator (d->begin ());}
+    iterator end () {return iterator (d->end ());}
+
+    const_iterator begin () const {return const_iterator (d->begin ());}
+    const_iterator end () const {return const_iterator (d->end ());}
+
+    const_iterator cbegin () const {return const_iterator (d->begin ());}
+    const_iterator cend () const {return const_iterator (d->end ());}
+
+    // Implementation details.
+    //
+  public:
+    explicit vector_value (D& d): d (&d) {}
+
+    vector_value (const vector_value&) = delete;
+    vector_value& operator= (const vector_value&) = delete; // Rebind or deep?
+
+    vector_value (vector_value&&) = default;
+    vector_value& operator= (vector_value&&) = default; //@@ TMP
+
+    explicit vector_value (std::nullptr_t): d (nullptr) {} //@@ TMP
+
+    D* d; // names
+  };
+
+  template <typename T>
+  struct value_traits<std::vector<T>>
+  {
+    using type = vector_value<T, names>;
+    using const_type = vector_value<T, const names>;
+
+    static type       as (value&);
+    static const_type as (const value&);
+
+    template <typename V> static void assign (value&, V);
+    template <typename V> static void append (value&, V);
+
+    static const std::string type_name;
+    static const build2::value_type value_type;
+  };
+
+  template <typename T, typename D>
+  struct value_traits<vector_value<T, D>>: value_traits<std::vector<T>> {};
+
+  using strings_value = vector_value<std::string, names>;
+  using const_strings_value = vector_value<std::string, const names>;
+
+  extern const value_type* strings_type;   // vector<string> aka strings
+  extern const value_type* dir_paths_type; // vector<dir_path> aka dir_paths
+  extern const value_type* names_type;     // vector<name> aka names
+
+  // map<K, V>
+  //
+  template <typename K, typename V, typename D>
+  struct map_value
+  {
+    template <typename F, typename S>
+    struct pair
+    {
+      using first_type = typename std::conditional<
+        std::is_reference<F>::value,
+        std::reference_wrapper<typename std::remove_reference<F>::type>,
+        F>::type;
+
+      using second_type = typename std::conditional<
+        std::is_reference<S>::value,
+        std::reference_wrapper<typename std::remove_reference<S>::type>,
+        S>::type;
+
+      first_type first;
+      second_type second;
+    };
+
+    template <typename I, typename T>
+    struct iterator_impl
+    {
+      using value_type = T;
+      using pointer = value_type*;
+      using reference = value_type; // Note: value.
+      using difference_type = typename I::difference_type;
+      using iterator_category = std::bidirectional_iterator_tag;
+
+      iterator_impl () = default;
+      iterator_impl (const I& i): i_ (i) {}
+
+      pointer operator-> () const = delete;
+      reference operator* () const
+      {
+        return value_type {as<K> (*i_), as<V> (*(i_ + 1))};
+      }
+
+      iterator_impl& operator++ () {i_ += 2; return *this;}
+      iterator_impl operator++ (int) {auto r (*this); operator++ (); return r;}
+
+      iterator_impl& operator-- () {i_ -= 2; return *this;}
+      iterator_impl operator-- (int) {auto r (*this); operator-- (); return r;}
+
+      bool operator== (const iterator_impl& y) const {return i_ == y.i_;}
+      bool operator!= (const iterator_impl& y) const {return i_ != y.i_;}
+
+    private:
+      I i_;
+    };
+
+    using size_type = typename D::size_type;
+
+    using value_type = pair<typename value_traits<K>::const_type,
+                            typename value_traits<V>::type>;
+
+    using const_value_type = pair<typename value_traits<K>::const_type,
+                                  typename value_traits<V>::const_type>;
+
+    // Make iterator the same as const_iterator if our data type is const.
+    //
+    using const_iterator =
+      iterator_impl<names::const_iterator, const_value_type>;
+    using iterator = typename std::conditional<
+      std::is_const<D>::value,
+      const_iterator,
+      iterator_impl<names::iterator, value_type>>::type;
+
+
+  public:
+    map_value&
+    operator= (std::map<K, V> m) {assign (std::move (m)); return *this;}
+
+    map_value&
+    assign (std::map<K, V>);
+
+    bool empty () const {return d->empty ();}
+    size_type size () const {return d->size ();}
+
+    iterator find (const K&);
+    const_iterator find (const K&) const;
+
+    iterator begin () {return iterator (d->begin ());}
+    iterator end () {return iterator (d->end ());}
+
+    const_iterator begin () const {return const_iterator (d->begin ());}
+    const_iterator end () const {return const_iterator (d->end ());}
+
+    // Implementation details.
+    //
+  public:
+    explicit map_value (D& d): d (&d) {}
+
+    map_value (const map_value&) = delete;
+    map_value& operator= (const map_value&) = delete; // Rebind or deep?
+
+    map_value (map_value&&) = default;
+    map_value& operator= (map_value&&) = delete;
+
+    D* d; // names
+  };
+
+  template <typename K, typename V>
+  struct value_traits<std::map<K, V>>
+  {
+    using type = map_value<K, V, names>;
+    using const_type = map_value<K, V, const names>;
+
+    static type       as (value&);
+    static const_type as (const value&);
+
+    template <typename M> static void assign (value&, M);
+    template <typename M> static void append (value&, M);
+
+    static const std::string type_name;
+    static const build2::value_type value_type;
+  };
+
+  template <typename K, typename V, typename D>
+  struct value_traits<map_value<K, V, D>>: value_traits<std::map<K, V>> {};
+}
+
+namespace std
+{
+  template <>
+  struct hash<build2::variable>: hash<string>
+  {
+    size_t
+    operator() (const build2::variable& v) const noexcept
+    {
+      return hash<string>::operator() (v.name);
+    }
+  };
+}
+
+namespace butl
+{
+  template <>
+  struct compare_prefix<build2::variable_cref>: compare_prefix<std::string>
+  {
+    typedef compare_prefix<std::string> base;
+
+    explicit
+    compare_prefix (char d): base (d) {}
+
+    bool
+    operator() (const build2::variable& x, const build2::variable& y) const
+    {
+      return base::operator() (x.name, y.name);
+    }
+
+    bool
+    prefix (const build2::variable& p, const build2::variable& k) const
+    {
+      return base::prefix (p.name, k.name);
+    }
+  };
+}
+
+namespace build2
+{
+  // variable_pool
+  //
+  using variable_pool_base = std::unordered_set<variable>;
+  struct variable_pool: private variable_pool_base
+  {
+    const variable&
+    find (string name, const build2::value_type* t = nullptr, char p = '\0')
+    {
+      return find (name, nullptr, t, p);
+    }
+
+    const variable&
+    find (string name,
+          variable_visibility v,
+          const build2::value_type* t = nullptr,
+          char p = '\0')
+    {
+      return find (name, &v, t, p);
+    }
+
+    using variable_pool_base::clear;
+
+  private:
+    const variable&
+    find (string name,
+          const variable_visibility* vv,
+          const build2::value_type* t,
+          char p)
+    {
+      auto r (
+        insert (
+          variable {
+            std::move (name),
+            t,
+            vv != nullptr ? *vv : variable_visibility::normal,
+            p}));
+      const variable& v (*r.first);
+
+      // Update type?
+      //
+      if (!r.second && t != nullptr && v.type != t)
+      {
+        assert (v.type == nullptr);
+        const_cast<variable&> (v).type = t; // Not changing the key.
+      }
+
+      // Change visibility? While this might at first seem like a bad idea,
+      // it can happen that the variable lookup happens before any values
+      // were set, in which case the variable will be entered with the
+      // default visibility.
+      //
+      if (!r.second && vv != nullptr && v.visibility != *vv)
+      {
+        assert (v.visibility == variable_visibility::normal); // Default.
+        const_cast<variable&> (v).visibility = *vv; // Not changing the key.
+      }
+
+      return v;
+    }
+  };
+
+  extern variable_pool var_pool;
+
+  // variable_map
+  //
+  struct variable_map
+  {
+    using map_type = butl::prefix_map<variable_cref, value, '.'>;
+    using size_type = map_type::size_type;
+
+    template <typename I>
+    struct iterator_adapter: I
+    {
+      iterator_adapter () = default;
+      iterator_adapter (const I& i): I (i) {}
+      typename I::reference operator* () const;
+      typename I::pointer operator-> () const;
+    };
+
+    using const_iterator = iterator_adapter<map_type::const_iterator>;
+
+    const value*
+    find (const variable& var) const
+    {
+      auto i (m_.find (var));
+      const value* r (i != m_.end () ? &i->second : nullptr);
+
+      // First access after being assigned a type?
+      //
+      if (r != nullptr && var.type != nullptr && r->type != var.type)
+        build2::assign (const_cast<value&> (*r), var.type, var);
+
+      return  r;
+    }
+
+    value*
+    find (const variable& var)
+    {
+      auto i (m_.find (var));
+      value* r (i != m_.end () ? &i->second : nullptr);
+
+      // First access after being assigned a type?
+      //
+      if (r != nullptr && var.type != nullptr && r->type != var.type)
+        build2::assign (*r, var.type, var);
+
+      return  r;
+    }
+
+    lookup<const value>
+    operator[] (const variable& var) const
+    {
+      return lookup<const value> (find (var), this);
+    }
+
+    lookup<const value>
+    operator[] (const std::string& name) const
+    {
+      return operator[] (var_pool.find (name));
+    }
+
+    // Non-const lookup. Only exposed on the map directly.
+    //
+    lookup<value>
+    operator[] (const variable& var)
+    {
+      return lookup<value> (find (var), this);
+    }
+
+    lookup<value>
+    operator[] (const std::string& name)
+    {
+      return operator[] (var_pool.find (name));
+    }
+
+    // The second member in the pair indicates whether the new
+    // value (which will be NULL) was assigned.
+    //
+    std::pair<std::reference_wrapper<value>, bool>
+    assign (const variable& var)
+    {
+      auto r (m_.emplace (var, value (var.type)));
+      value& v (r.first->second);
+
+      // First access after being assigned a type?
+      //
+      if (!r.second && var.type != nullptr && v.type != var.type)
+        build2::assign (v, var.type, var);
+
+      return std::make_pair (std::reference_wrapper<value> (v), r.second);
+    }
+
+    std::pair<std::reference_wrapper<value>, bool>
+    assign (const std::string& name)
+    {
+      return assign (var_pool.find (name));
+    }
+
+    std::pair<const_iterator, const_iterator>
+    find_namespace (const std::string& ns) const
+    {
+      auto r (m_.find_prefix (var_pool.find (ns)));
+      return std::make_pair (const_iterator (r.first),
+                             const_iterator (r.second));
+    }
+
+    const_iterator
+    begin () const {return m_.begin ();}
+
+    const_iterator
+    end () const {return m_.end ();}
+
+    bool
+    empty () const {return m_.empty ();}
+
+    size_type
+    size () const {return m_.size ();}
+
+  private:
+    map_type m_;
+  };
+
+  // Target type/pattern-specific variables.
+  //
+  // @@ In quite a few places we assume that we can store a reference
+  //    to the returned value (e.g., install::lookup_install()). If
+  //    we "instantiate" the value on the fly, then we will need to
+  //    consider its lifetime.
+  //
+  using variable_pattern_map = std::map<std::string, variable_map>;
+
+  struct variable_type_map: std::map<std::reference_wrapper<const target_type>,
+                                     variable_pattern_map>
+  {
+    build2::lookup<const value>
+    lookup (const target_type&, const string& name, const variable&) const;
+  };
+}
+
+#include <build2/variable.ixx>
+#include <build2/variable.txx>
+
+#endif // BUILD2_VARIABLE
-- 
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