Use an auto_descriptor pointer to manage a bound result LOB

This simplifies resource management in the generated code.

3 files changed, 32 insertions, 2 deletions

diff --git a/odb/oracle/oracle-fwd.hxx b/odb/oracle/oracle-fwd.hxx
index bc400d1..813414c 100644
--- a/odb/oracle/oracle-fwd.hxx
+++ b/odb/oracle/oracle-fwd.hxx
@@ -24,6 +24,9 @@ typedef struct OCIStmt OCIStmt;
 typedef struct OCIAuthInfo OCIAuthInfo;
 typedef struct OCITrans OCITrans;
 
+typedef struct OCIParam OCIParam;
+typedef struct OCILobLocator OCILobLocator;
+
 #include <odb/post.hxx>
 
 #endif // ODB_ORACLE_ORACLE_FWD_HXX
diff --git a/odb/oracle/oracle-types.hxx b/odb/oracle/oracle-types.hxx
index 1f2c8a0..33e0f33 100644
--- a/odb/oracle/oracle-types.hxx
+++ b/odb/oracle/oracle-types.hxx
@@ -10,6 +10,7 @@
 
 #include <odb/oracle/version.hxx>
 #include <odb/oracle/oracle-fwd.hxx>
+#include <odb/oracle/auto-descriptor.hxx>
 
 namespace odb
 {
@@ -92,7 +93,7 @@ namespace odb
                         // 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
-                        // OCILobLocator*.
+                        // auto_descriptor<OCILobLocator>*.
       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 5d992b7..ab0068c 100644
--- a/odb/oracle/statement.cxx
+++ b/odb/oracle/statement.cxx
@@ -207,11 +207,37 @@ 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.
+          //
+          auto_descriptor<OCILobLocator>* lob (
+            reinterpret_cast<auto_descriptor<OCILobLocator>*>  (b->size));
+
+          if (lob->get () == 0)
+          {
+            OCILobLocator* h (0);
+
+            sword r (OCIDescriptorAlloc (conn_.database ().environment (),
+                                         reinterpret_cast<void**> (&h),
+                                         OCI_DTYPE_LOB,
+                                         0,
+                                         0));
+
+            // OCIDescriptorAlloc will return OCI_SUCCESS on success, or
+            // OCI_INVALID_HANDLE on an out-of-memory condition.
+            //
+            if (r != OCI_SUCCESS)
+              throw bad_alloc ();
+
+            lob->reset (h);
+          }
+
           sword r (OCIDefineByPos (stmt_,
                                    &h,
                                    err,
                                    i,
-                                   reinterpret_cast<OCILobLocator*> (b->size),
+                                   lob,
                                    sizeof (OCILobLocator*),
                                    sqlt_lookup[b->type],
                                    b->indicator,