From 951f324ae01c4d8f9cbe1edb19b5f1c370f825a2 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Thu, 3 Nov 2011 10:05:55 +0200
Subject: Add position context to LOB result callback

It turns out position context can be useful in result handling as well.
---
 odb/oracle/oracle-types.hxx | 14 +++++++++-----
 odb/oracle/statement.cxx    |  2 ++
 odb/oracle/traits.cxx       |  6 +++---
 odb/oracle/traits.hxx       | 18 +++++++++++++++---
 4 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/odb/oracle/oracle-types.hxx b/odb/oracle/oracle-types.hxx
index 0687335..3327c57 100644
--- a/odb/oracle/oracle-types.hxx
+++ b/odb/oracle/oracle-types.hxx
@@ -48,10 +48,14 @@ namespace odb
     // the database. If false is returned, database_exception is thrown.
     //
     typedef bool (*result_callback_type) (
-      void* context,   // [in] The user context.
-      void* buffer,    // [in] A buffer containing the result data.
-      ub4 size,        // [in] The result data size in bytes.
-      chunk_position); // [in] The position of this chunk.
+      void* context,         // [in] The user context.
+      ub4* position_context, // [in] A position context. A callback is free to
+                             // use this to track position information. This is
+                             // initialized to zero before the callback is
+                             // invoked for the first time.
+      void* buffer,          // [in] A buffer containing the result data.
+      ub4 size,              // [in] The result data size in bytes.
+      chunk_position);       // [in] The position of this chunk.
 
     union lob_callback
     {
@@ -98,7 +102,7 @@ namespace odb
 
       buffer_type type; // The type stored by buffer.
       void* buffer;     // Data buffer pointer. When result callbacks are in
-                        // use, this is interpreted as an lob_auto_descriptor*.
+                        // use, this is interpreted as a lob_auto_descriptor*.
       ub2* size;        // The number of bytes in buffer. When parameter
                         // callbacks are in use, this is interpreted as a ub4*
                         // indicating the current position. For LOB result
diff --git a/odb/oracle/statement.cxx b/odb/oracle/statement.cxx
index 476377d..c1747a3 100644
--- a/odb/oracle/statement.cxx
+++ b/odb/oracle/statement.cxx
@@ -465,6 +465,7 @@ namespace odb
           auto_descriptor<OCILobLocator>& locator (
             *reinterpret_cast<auto_descriptor<OCILobLocator>*> (b->buffer));
 
+          ub4 position (0); // Position context.
           ub1 piece (OCI_FIRST_PIECE);
 
           // Setting the value pointed to by the byte_amt argument to 0 on the
@@ -517,6 +518,7 @@ namespace odb
             // returned from a user callback. We simulate this.
             //
             if (!(*b->callback->result) (b->context->result,
+                                         &position,
                                          lob_buffer.data (),
                                          static_cast<ub4> (read),
                                          cp))
diff --git a/odb/oracle/traits.cxx b/odb/oracle/traits.cxx
index 40543ba..af0266f 100644
--- a/odb/oracle/traits.cxx
+++ b/odb/oracle/traits.cxx
@@ -104,7 +104,7 @@ namespace odb
     //
 
     bool string_lob_value_traits::
-    result_callback (void* c, void* b, ub4 s, chunk_position p)
+    result_callback (void* c, ub4*, void* b, ub4 s, chunk_position p)
     {
       string& v (*static_cast<string*> (c));
 
@@ -173,7 +173,7 @@ namespace odb
     //
 
     bool default_value_traits<std::vector<char>, id_blob>::
-    result_callback (void* c, void* b, ub4 s, chunk_position p)
+    result_callback (void* c, ub4*, void* b, ub4 s, chunk_position p)
     {
       value_type& v (*static_cast<value_type*> (c));
 
@@ -222,7 +222,7 @@ namespace odb
     //
 
     bool default_value_traits<std::vector<unsigned char>, id_blob>::
-    result_callback (void* c, void* b, ub4 s, chunk_position p)
+    result_callback (void* c, ub4*, void* b, ub4 s, chunk_position p)
     {
       value_type& v (*static_cast<value_type*> (c));
 
diff --git a/odb/oracle/traits.hxx b/odb/oracle/traits.hxx
index edaeebf..8edaa54 100644
--- a/odb/oracle/traits.hxx
+++ b/odb/oracle/traits.hxx
@@ -668,7 +668,11 @@ namespace odb
       }
 
       static bool
-      result_callback (void* context, void* buffer, ub4 size, chunk_position);
+      result_callback (void* context,
+                       ub4* position_context,
+                       void* buffer,
+                       ub4 size,
+                       chunk_position);
 
       static bool
       param_callback (const void* context,
@@ -799,7 +803,11 @@ namespace odb
       }
 
       static bool
-      result_callback (void* context, void* buffer, ub4 size, chunk_position);
+      result_callback (void* context,
+                       ub4* position_context,
+                       void* buffer,
+                       ub4 size,
+                       chunk_position);
 
       static bool
       param_callback (const void* context,
@@ -848,7 +856,11 @@ namespace odb
       }
 
       static bool
-      result_callback (void* context, void* buffer, ub4 size, chunk_position);
+      result_callback (void* context,
+                       ub4* position_context,
+                       void* buffer,
+                       ub4 size,
+                       chunk_position);
 
       static bool
       param_callback (const void* context,
-- 
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