From 693b99238ad003daa9e79c09fc10bcb0289669c0 Mon Sep 17 00:00:00 2001
From: Constantin Michael <constantin@codesynthesis.com>
Date: Mon, 17 Oct 2011 08:59:01 +0200
Subject: Allocate LOB manipulation buffer in connection instance instead of in
 image

---
 odb/oracle/connection.hxx   |  9 +++++++++
 odb/oracle/oracle-types.hxx |  8 ++++----
 odb/oracle/statement.cxx    | 36 +++++++++++++++++++++++-------------
 3 files changed, 36 insertions(+), 17 deletions(-)

diff --git a/odb/oracle/connection.hxx b/odb/oracle/connection.hxx
index 1440c25..12add74 100644
--- a/odb/oracle/connection.hxx
+++ b/odb/oracle/connection.hxx
@@ -15,6 +15,7 @@
 #include <odb/connection.hxx>
 
 #include <odb/details/shared-ptr.hxx>
+#include <odb/details/buffer.hxx>
 
 #include <odb/oracle/version.hxx>
 #include <odb/oracle/forward.hxx>
@@ -81,6 +82,12 @@ namespace odb
         return *statement_cache_;
       }
 
+      details::buffer&
+      lob_buffer ()
+      {
+        return lob_buffer_;
+      }
+
     private:
       connection (const connection&);
       connection& operator= (const connection&);
@@ -96,6 +103,8 @@ namespace odb
       auto_handle<OCISvcCtx> handle_;
 
       std::auto_ptr<statement_cache_type> statement_cache_;
+
+      details::buffer lob_buffer_;
     };
   }
 }
diff --git a/odb/oracle/oracle-types.hxx b/odb/oracle/oracle-types.hxx
index 091a6d5..1e48129 100644
--- a/odb/oracle/oracle-types.hxx
+++ b/odb/oracle/oracle-types.hxx
@@ -97,12 +97,12 @@ namespace odb
       };
 
       buffer_type type; // The type stored by buffer.
-      void* buffer;     // Data buffer pointer.
+      void* buffer;     // Data buffer pointer. When result callbacks are in
+                        // use, this is interpreted as an
+                        // auto_descriptor<OCILobLocator>*.
       ub2* size;        // The number of bytes in buffer. When parameter
                         // callbacks are in use, this is interpreted as a ub4*
-                        // indicating the current position. When result
-                        // callbacks are in use, this is interpreted as an
-                        // auto_descriptor<OCILobLocator>*.
+                        // indicating the current position.
       ub4 capacity;     // The maximum number of bytes that can be stored in
                         // buffer.
       sb2* indicator;   // Pointer to an OCI indicator variable.
diff --git a/odb/oracle/statement.cxx b/odb/oracle/statement.cxx
index ff02f06..2f7311d 100644
--- a/odb/oracle/statement.cxx
+++ b/odb/oracle/statement.cxx
@@ -4,6 +4,7 @@
 // license   : ODB NCUEL; see accompanying LICENSE file
 
 #include <cassert>
+#include <limits>
 
 #include <oci.h>
 
@@ -178,7 +179,13 @@ namespace odb
                                err,
                                o,
                                callback ? 0 : b->buffer,
-                               static_cast<sb4> (b->capacity),
+                               // When parameter callbacks are in use, set the
+                               // allowable data length to the maximum
+                               // possible.
+                               //
+                               callback
+                                 ? std::numeric_limits<sb4>::max ()
+                                 : static_cast<sb4> (b->capacity),
                                param_sqlt_lookup[b->type],
                                callback ? 0 : b->indicator,
                                callback ? 0 : b->size,
@@ -207,6 +214,9 @@ namespace odb
 
         if (callback)
         {
+          b->buffer = conn_.lob_buffer ().data ();
+          b->capacity = conn_.lob_buffer ().capacity ();
+
           r = OCIBindDynamic (h, err, b, &param_callback_proxy, 0, 0);
 
           if (r == OCI_ERROR || r == OCI_INVALID_HANDLE)
@@ -230,12 +240,12 @@ namespace odb
             b->type == bind::clob ||
             b->type == bind::nclob)
         {
-          // When binding a LOB result, the bind::size member is reinterpreted
-          // as a pointer to an auto_descriptor<OCILobLocator>. If the
-          // descriptor has not yet been allocated, it is allocated now.
+          // When binding a LOB result, the bind::buffer member is
+          // reinterpreted as a pointer to an auto_descriptor<OCILobLocator>.
+          // If the descriptor has not yet been allocated, it is allocated now.
           //
           auto_descriptor<OCILobLocator>* lob (
-            reinterpret_cast<auto_descriptor<OCILobLocator>*> (b->size));
+            reinterpret_cast<auto_descriptor<OCILobLocator>*> (b->buffer));
 
           if (lob->get () == 0)
           {
@@ -352,12 +362,8 @@ namespace odb
              b->type == bind::nclob) &&
             *b->indicator != -1 && b->callback->result != 0)
         {
-          // If b->capacity is 0, we will be stuck in an infinite loop.
-          //
-          assert (b->capacity != 0);
-
           auto_descriptor<OCILobLocator>& locator (
-            *reinterpret_cast<auto_descriptor<OCILobLocator>* > (b->size));
+            *reinterpret_cast<auto_descriptor<OCILobLocator>* > (b->buffer));
 
           ub1 piece (OCI_FIRST_PIECE);
 
@@ -369,6 +375,10 @@ namespace odb
           ub8 read (0);
           ub1 cs_form (b->type == bind::nclob ? SQLCS_NCHAR : SQLCS_IMPLICIT);
 
+          // Allocate buffer space if necessary.
+          //
+          conn_.lob_buffer ().capacity (4096);
+
           sword r;
           do
           {
@@ -378,8 +388,8 @@ namespace odb
                              &read,
                              0,
                              1,
-                             b->buffer,
-                             b->capacity,
+                             conn_.lob_buffer ().data (),
+                             conn_.lob_buffer ().capacity (),
                              piece,
                              0,
                              0,
@@ -404,7 +414,7 @@ namespace odb
             // returned from a user callback. We simulate this.
             //
             if (!(*b->callback->result) (b->context->result,
-                                         b->buffer,
+                                         conn_.lob_buffer ().data (),
                                          static_cast<ub4> (read),
                                          cp))
               throw database_exception (24343, "user defined callback error");
-- 
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