Corrections and additions to LOB parameter and results callback implementation

1 files changed, 28 insertions, 22 deletions

diff --git a/odb/oracle/oracle-types.hxx b/odb/oracle/oracle-types.hxx
index 5911d4f..4d347d0 100644
--- a/odb/oracle/oracle-types.hxx
+++ b/odb/oracle/oracle-types.hxx
@@ -19,25 +19,35 @@ namespace odb
     {
       ub2 type;       // The type stored by buffer. This must be an external
                       // OCI type identifier of the form SQLT_XXX.
-      void* buffer;   // Image buffer pointer. If this bind is associated with
-                      // an output LOB column, interpret as an OCILobLocator*.
-      ub2* size;      // The number of bytes in buffer. Due to
-                      // inconsistencies in the OCI interface, this will be
-                      // interpreted as a ub4 when callbacks are in use.
-      sb4 capacity;   // The maximum number of bytes that can be stored in
+      void* buffer;   // Data buffer pointer.
+      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 'type'
+                      // specifies a LOB type, this is interpreted as an
+                      // OCILobLocator*.
+      ub4 capacity;   // The maximum number of bytes that can be stored in
                       // buffer.
       sb2* indicator; // Pointer to an OCI indicator variable.
 
+      enum piece
+      {
+        whole,
+        first,
+        next,
+        last
+      };
+
       // Callback function signature used to specify LOB parameters that are
       // passed to the database.
       //
       typedef bool (*param_callback_type) (
-        void** context,    // [in/out] The user context.
+        void* context,     // [in/out] The user context.
         void** buffer,     // [out] On return, a pointer to a buffer containing
                            // parameter data.
         ub4* size,         // [out] The parameter data length in bytes.
-        bool* last,        // [out] True if buffer contains the last piece of
-                           // data.
+        ub4* position,     // [in/out] A position context. This value remains
+                           // unchanged between callback invocations.
+        piece*,            // [out] The piece type for this segment of data.
         void* temp_buffer, // [in] A temporary buffer that may be used if
                            // required. The 'buffer' parameter should specify
                            // this buffer on return if it is used.
@@ -47,25 +57,21 @@ namespace odb
       // the database.
       //
       typedef bool (*result_callback_type) (
-        void** context, // [in/out] The user context.
-        void* buffer,   // [in] A buffer containing the result data.
-        ub4 size,       // [in] The result data length in bytes.
-        bool last);     // [in] True if this is the last piece of result data.
+        void* context, // [in/out] The user context.
+        void* buffer,  // [in] A buffer containing the result data.
+        ub4 size,      // [in] The result data length in bytes.
+        piece);        // [in] The piece type for this segment of data.
 
-      param_callback_type param_callback;
-      result_callback_type result_callback;
+      union
+      {
+        param_callback_type param;
+        result_callback_type result;
+      } callback;
 
       // This pointer is provided to the user through the 'context' parameter
       // in both parameter and result callback functions.
       //
       void* callback_context;
-
-      // This flag is used exclusively during parameter callback invocation.
-      // If set, it indicates that this is the first time the callback is
-      // being invoked for this bind instance, and thus OCI is requesting
-      // the first piece of parameter data.
-      //
-      bool first_piece;
     };
   }
 }