From 30b664c0561cc9f6d2bd24f7bce9b6c57fb52320 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Mon, 15 Nov 2010 17:46:28 +0200
Subject: Add support for custom object pointers

New option: --default-pointer. New object pragma specifier: pointer.
---
 odb/forward.hxx        |  7 ++-----
 odb/pointer-traits.hxx |  6 +++---
 odb/result.hxx         | 23 ++++++++++++++++++-----
 odb/result.txx         | 14 +++-----------
 odb/traits.hxx         | 35 +++++++++++++++++------------------
 5 files changed, 43 insertions(+), 42 deletions(-)

(limited to 'odb')

diff --git a/odb/forward.hxx b/odb/forward.hxx
index bd6cbcb..dbd3628 100644
--- a/odb/forward.hxx
+++ b/odb/forward.hxx
@@ -19,13 +19,10 @@ namespace odb
     template <typename T>
     class object_traits;
 
-    template <typename T>
-    class object_memory;
-
-    template <typename T>
+    template <typename T, typename P>
     class object_factory;
 
-    template <typename P>
+    template <typename T, typename P>
     class pointer_factory;
 
     template <typename T>
diff --git a/odb/pointer-traits.hxx b/odb/pointer-traits.hxx
index 18162e4..4c94709 100644
--- a/odb/pointer-traits.hxx
+++ b/odb/pointer-traits.hxx
@@ -25,13 +25,13 @@ namespace odb
     nop_guard () {}
 
     explicit
-    nop_guard (P) {}
+    nop_guard (const P&) {}
 
     void
     release () {}
 
     void
-    reset (P) {}
+    reset (const P&) {}
   };
 
   // Default implementation that should work for any sensible smart
@@ -69,7 +69,7 @@ namespace odb
     static bool
     null_ptr (const pointer& p)
     {
-      return get_ptr () == 0;
+      return get_ptr (p) == 0;
     }
 
   public:
diff --git a/odb/result.hxx b/odb/result.hxx
index ff9f057..cf924c3 100644
--- a/odb/result.hxx
+++ b/odb/result.hxx
@@ -40,8 +40,19 @@ namespace odb
     typedef typename traits::pointer_type pointer_type;
     typedef typename traits::pointer_traits pointer_traits;
 
-    pointer_type
-    current (bool release);
+    // To make this work with all kinds of pointers (naked, std::auto_ptr,
+    // shared), we need to make sure we don't make any copies of the
+    // pointer on the return path.
+    //
+    pointer_type&
+    current ();
+
+    void
+    release ()
+    {
+      current_ = pointer_type ();
+      guard_.release ();
+    }
 
     bool
     end () const
@@ -100,7 +111,7 @@ namespace odb
     reference
     operator* () const
     {
-      return pointer_traits::get_ref (res_->current (false));
+      return pointer_traits::get_ref (res_->current ());
     }
 
     // Our value_type is already a pointer so return it instead of
@@ -110,7 +121,7 @@ namespace odb
     pointer
     operator-> () const
     {
-      return pointer_traits::get_ptr (res_->current (false));
+      return pointer_traits::get_ptr (res_->current ());
     }
 
     result_iterator&
@@ -133,7 +144,9 @@ namespace odb
     typename object_traits<T>::pointer_type
     load ()
     {
-      return res_->current (true);
+      typename object_traits<T>::pointer_type r (res_->current ());
+      res_->release ();
+      return r;
     }
 
     void
diff --git a/odb/result.txx b/odb/result.txx
index e58af1f..3068890 100644
--- a/odb/result.txx
+++ b/odb/result.txx
@@ -12,8 +12,8 @@ namespace odb
   }
 
   template <typename T>
-  typename result_impl<T>::pointer_type result_impl<T>::
-  current (bool release)
+  typename result_impl<T>::pointer_type& result_impl<T>::
+  current ()
   {
     if (pointer_traits::null_ptr (current_) && !end_)
     {
@@ -21,14 +21,6 @@ namespace odb
       current (pointer_traits::get_ref (current_));
     }
 
-    pointer_type r (current_);
-
-    if (release)
-    {
-      current_ = pointer_type ();
-      guard_.release ();
-    }
-
-    return r;
+    return current_;
   }
 }
diff --git a/odb/traits.hxx b/odb/traits.hxx
index 318d88b..bc25dcb 100644
--- a/odb/traits.hxx
+++ b/odb/traits.hxx
@@ -16,8 +16,7 @@ namespace odb
   // template <typename T>
   // class access::object_traits;
   //
-  // Specializations should inherit from object_memory, object_factory
-  // and define the following members:
+  // Specializations should define the following members:
   //
   // id_type               - object id (primary key) type
   // id_type id (const T&) - get object id
@@ -30,39 +29,35 @@ namespace odb
   //
   //
 
-  template <typename T>
-  class access::object_memory
-  {
-  public:
-    typedef T* pointer_type;
-  };
-
-  template <typename T>
+  template <typename T, typename P>
   class access::object_factory
   {
   public:
-    static typename object_memory<T>::pointer_type
+    typedef T object_type;
+    typedef P pointer_type;
+
+    static P
     create ()
     {
       // By default use pointer-specific construction.
       //
-      return
-        pointer_factory<typename object_memory<T>::pointer_type>::create ();
+      return pointer_factory<T, P>::create ();
     }
   };
 
-  template <typename P>
+  template <typename T, typename P>
   class access::pointer_factory
   {
   public:
-    typedef typename pointer_traits<P>::type object_type;
+    typedef T object_type;
+    typedef P pointer_type;
 
     static P
     create ()
     {
-      void* v (pointer_traits<P>::allocate (sizeof (object_type)));
+      void* v (pointer_traits<P>::allocate (sizeof (T)));
       mem_guard g (v);
-      P p (new (v) object_type);
+      P p (new (v) T);
       g.release ();
       return p;
     }
@@ -77,8 +72,12 @@ namespace odb
   };
 
   template <typename T>
-  struct object_traits: access::object_traits<T>
+  struct object_traits: access::object_traits<T>,
+    access::object_factory<T, typename access::object_traits<T>::pointer_type>
   {
+    typedef typename access::object_traits<T>::object_type object_type;
+    typedef typename access::object_traits<T>::pointer_type pointer_type;
+
     typedef
     odb::pointer_traits<typename access::object_traits<T>::pointer_type>
     pointer_traits;
-- 
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