Add query support

1 files changed, 188 insertions, 0 deletions

diff --git a/odb/result.hxx b/odb/result.hxx
new file mode 100644
index 0000000..979988a
--- /dev/null
+++ b/odb/result.hxx
@@ -0,0 +1,188 @@
+// file      : odb/result.hxx
+// author    : Boris Kolpackov <boris@codesynthesis.com>
+// copyright : Copyright (c) 2009-2010 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#ifndef ODB_RESULT_HXX
+#define ODB_RESULT_HXX
+
+#include <cstddef>  // std::ptrdiff_t, std::size_t
+#include <iterator> // iterator categories
+
+#include <odb/forward.hxx>
+#include <odb/shared-ptr.hxx>
+
+namespace odb
+{
+  template <typename T>
+  class result;
+
+  template <typename T>
+  class result_impl;
+
+  template <typename T>
+  class result_iterator
+  {
+  public:
+    typedef typename object_traits<T>::pointer_type value_type;
+    typedef value_type& reference;
+    typedef value_type* pointer;
+    typedef std::ptrdiff_t difference_type;
+    typedef std::input_iterator_tag iterator_category;
+
+  public:
+    result_iterator ()
+        : res_ (0)
+    {
+    }
+
+    explicit
+    result_iterator (result_impl<T>& res)
+        : res_ (&res)
+    {
+    }
+
+    // Input iterator requirements.
+    //
+  public:
+    value_type
+    operator* () const
+    {
+      return res_->current (true);
+    }
+
+    // Our value_type is already a pointer so return it instead of
+    // a pointer to it (operator-> will just have to go one deeper
+    // in the latter case).
+    //
+    value_type
+    operator-> () const
+    {
+      return res_->current (false);
+    }
+
+    result_iterator&
+    operator++ ()
+    {
+      res_->next ();
+      return *this;
+    }
+
+    result_iterator
+    operator++ (int)
+    {
+      // All non-end iterators for a result object move together.
+      //
+      res_->next ();
+      return *this;
+    }
+
+    bool
+    equal (const result_iterator& j)
+    {
+      return  (res_ ? res_->current (false) : 0) ==
+        (j.res_ ? j.res_->current (false) : 0);
+    }
+
+  private:
+    result_impl<T>* res_;
+  };
+
+  // Input iterator requirements.
+  //
+  template <typename T>
+  inline bool
+  operator== (result_iterator<T> i, result_iterator<T> j)
+  {
+    return i.equal (j);
+  }
+
+  template <typename T>
+  inline bool
+  operator!= (result_iterator<T> i, result_iterator<T> j)
+  {
+    return !i.equal (j);
+  }
+
+  //
+  //
+  template <typename T>
+  class result_impl: public shared_base
+  {
+  public:
+    virtual
+    ~result_impl ();
+
+  protected:
+    friend class result<T>;
+    friend class result_iterator<T>;
+
+    virtual typename object_traits<T>::pointer_type
+    current (bool release) = 0;
+
+    virtual void
+    next () = 0;
+  };
+
+  template <typename T>
+  class result
+  {
+  public:
+    typedef typename object_traits<T>::pointer_type value_type;
+    typedef value_type*       pointer;
+    typedef const value_type* const_pointer;
+    typedef value_type&       reference;
+    typedef const value_type& const_reference;
+
+    typedef result_iterator<T> iterator;
+
+    typedef std::size_t    size_type;
+    typedef std::ptrdiff_t difference_type;
+
+  public:
+    result (shared_ptr<result_impl<T> > impl)
+        : impl_ (impl)
+    {
+    }
+
+    /*
+    result&
+    operator= (shared_ptr<result_impl<T> > impl)
+    {
+      impl_ = impl;
+    }
+    */
+
+  public:
+    iterator
+    begin ()
+    {
+      return iterator (*impl_);
+    }
+
+    iterator
+    end ()
+    {
+      return iterator ();
+    }
+
+  public:
+    operator shared_ptr<result_impl<T> > ()
+    {
+      return impl_;
+    }
+
+    // Copying or assignment of results is not supported.
+    //
+  private:
+    result (const result&);
+    result& operator= (const result&);
+
+  private:
+    shared_ptr<result_impl<T> > impl_;
+  };
+}
+
+#include <odb/result.txx>
+
+#endif // ODB_RESULT_HXX