From 7b9c412736f51965473649cac8caf5e933ae6b9e Mon Sep 17 00:00:00 2001
From: Constantin Michael <constantin@codesynthesis.com>
Date: Tue, 27 Sep 2011 17:15:48 +0200
Subject: Pass parameter callback user context as a const void*

This avoids usage of const_cast when manipulating the const qualified values
in set_image functions within the traits implementations.
---
 odb/oracle/oracle-types.hxx |  2 +-
 odb/oracle/traits.cxx       | 12 ++++++------
 odb/oracle/traits.hxx       | 18 +++++++++---------
 3 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/odb/oracle/oracle-types.hxx b/odb/oracle/oracle-types.hxx
index a3b45c6..c027e5d 100644
--- a/odb/oracle/oracle-types.hxx
+++ b/odb/oracle/oracle-types.hxx
@@ -28,7 +28,7 @@ namespace odb
     // statement execution is aborted.
     //
     typedef bool (*param_callback_type) (
-      void* context,         // [in] The user context.
+      const void* context,   // [in] The user context.
       ub4* position_context, // [in] A position context. A callback is free to
                              // use this to track position information.
       void** buffer,         // [out] On return, a pointer to a buffer
diff --git a/odb/oracle/traits.cxx b/odb/oracle/traits.cxx
index c934cc1..a37f440 100644
--- a/odb/oracle/traits.cxx
+++ b/odb/oracle/traits.cxx
@@ -85,7 +85,7 @@ namespace odb
     }
 
     bool string_lob_value_traits::
-    param_callback (void* ctx,
+    param_callback (const void* ctx,
                     ub4* pos_ctx,
                     void** b,
                     ub4* s,
@@ -93,7 +93,7 @@ namespace odb
                     void* temp_b,
                     ub4 cap)
     {
-      const string& v (*reinterpret_cast<string*> (ctx));
+      const string& v (*static_cast<const string*> (ctx));
 
       // @@ We rely on *pos_ctx == 0 for the first call. Make sure that this is
       // set by the generated code, and update comment in oracle-types.hxx
@@ -121,7 +121,7 @@ namespace odb
     //
 
     bool c_string_lob_value_traits::
-    param_callback (void* ctx,
+    param_callback (const void* ctx,
                     ub4* pos_ctx,
                     void** b,
                     ub4* s,
@@ -129,7 +129,7 @@ namespace odb
                     void* temp_b,
                     ub4 cap)
     {
-      const char* v (reinterpret_cast<char*> (ctx));
+      const char* v (static_cast<const char*> (ctx));
 
       // @@ We rely on *pos_ctx == 0 for the first call. Make sure that this is
       // set by the generated code, and update comment in oracle-types.hxx
@@ -183,7 +183,7 @@ namespace odb
     }
 
     bool default_value_traits<std::vector<char>, id_blob>::
-    param_callback (void* ctx,
+    param_callback (const void* ctx,
                     ub4* pos_ctx,
                     void** b,
                     ub4* s,
@@ -191,7 +191,7 @@ namespace odb
                     void* temp_b,
                     ub4 cap)
     {
-      const value_type& v (*reinterpret_cast<value_type*> (ctx));
+      const value_type& v (*static_cast<const value_type*> (ctx));
 
       // @@ We rely on *position_context == 0 for the first call. Make sure
       // that this is set by the generated code and update the comment in
diff --git a/odb/oracle/traits.hxx b/odb/oracle/traits.hxx
index 687d28a..cedf064 100644
--- a/odb/oracle/traits.hxx
+++ b/odb/oracle/traits.hxx
@@ -516,20 +516,20 @@ namespace odb
 
       static void
       set_image (param_callback_type& cb,
-                 void*& context,
+                 const void*& context,
                  bool& is_null,
                  const std::string& v)
       {
         is_null = false;
         cb = &param_callback;
-        context = const_cast<std::string*> (&v);
+        context = &v;
       }
 
       static bool
       result_callback (void* context, void* buffer, ub4 size, chunk_position);
 
       static bool
-      param_callback (void* context,
+      param_callback (const void* context,
                       ub4* position_context,
                       void** buffer,
                       ub4* size,
@@ -565,17 +565,17 @@ namespace odb
 
       static void
       set_image (param_callback_type& cb,
-                 void*& context,
+                 const void*& context,
                  bool& is_null,
                  const char* v)
       {
         is_null = false;
         cb = &param_callback;
-        context = const_cast<char*> (v);
+        context = v;
       }
 
       static bool
-      param_callback (void* context,
+      param_callback (const void* context,
                       ub4* position_context,
                       void** buffer,
                       ub4* size,
@@ -646,20 +646,20 @@ namespace odb
 
       static void
       set_image (param_callback_type& cb,
-                 void*& context,
+                 const void*& context,
                  bool& is_null,
                  const value_type& v)
       {
         is_null = false;
         cb = &param_callback;
-        context = const_cast<value_type*> (&v);
+        context = &v;
       }
 
       static bool
       result_callback (void* context, void* buffer, ub4 size, chunk_position);
 
       static bool
-      param_callback (void* context,
+      param_callback (const void* context,
                       ub4* position_context,
                       void** buffer,
                       ub4* size,
-- 
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