Merge pull request #88 from mloskot/issue-81

Fix OUT direction of IN/OUT procedure parameter

src/backends/oracle/test/test-oracle.cpp

@@ -343,50 +343,73 @@ struct returns_null_procedure_creator : public procedure_creator_base
 
 void test7()
 {
-    session sql(backEnd, connectString);
     {
-        basic_table_creator tableCreator(sql);
+        session sql(backEnd, connectString);
+        {
+            basic_table_creator tableCreator(sql);
 
-        int id(1);
-        string_holder in("my string");
-        sql << "insert into soci_test(id, name) values(:id, :name)", use(id), use(in);
+            int id(1);
+            string_holder in("my string");
+            sql << "insert into soci_test(id, name) values(:id, :name)", use(id), use(in);
 
-        string_holder out;
-        sql << "select name from soci_test", into(out);
-        assert(out.get() == "my string");
+            string_holder out;
+            sql << "select name from soci_test", into(out);
+            assert(out.get() == "my string");
 
-        row r;
-        sql << "select * from soci_test", into(r);
-        string_holder dynamicOut = r.get<string_holder>(1);
-        assert(dynamicOut.get() == "my string");
+            row r;
+            sql << "select * from soci_test", into(r);
+            string_holder dynamicOut = r.get<string_holder>(1);
+            assert(dynamicOut.get() == "my string");
+        }
     }
+    std::cout << "test 7 passed" << std::endl;
+}
 
-    // FIXME: see https://github.com/SOCI/soci/issues/81
-    //        temporarily disabled to allow testing of Oracle on travis-ci
-#if 0
-    // test procedure with user-defined type as in-out parameter
+void test7inout()
+{
     {
-        in_out_procedure_creator procedureCreator(sql);
+        session sql(backEnd, connectString);
 
-        string_holder sh("test");
-        procedure proc = (sql.prepare << "soci_test(:s)", use(sh));
-        proc.execute(1);
-        assert(sh.get() == "testtest");
+        // test procedure with user-defined type as in-out parameter
+        {
+            in_out_procedure_creator procedureCreator(sql);
+
+            std::string sh("test");
+            procedure proc = (sql.prepare << "soci_test(:s)", use(sh));
+            proc.execute(1);
+            assert(sh == "testtest");
+        }
+
+        // test procedure with user-defined type as in-out parameter
+        {
+            in_out_procedure_creator procedureCreator(sql);
+
+            string_holder sh("test");
+            procedure proc = (sql.prepare << "soci_test(:s)", use(sh));
+            proc.execute(1);
+            assert(sh.get() == "testtest");
+        }
     }
-#endif
-    // test procedure which returns null
+    std::cout << "test 7 inout passed" << std::endl;
+}
+
+void test7outnull()
+{
     {
-         returns_null_procedure_creator procedureCreator(sql);
+        session sql(backEnd, connectString);
 
-         string_holder sh;
-         indicator ind = i_ok;
-         procedure proc = (sql.prepare << "soci_test(:s)", use(sh, ind));
-         proc.execute(1);
-         assert(ind == i_null);
-    }
+        // test procedure which returns null
+        {
+            returns_null_procedure_creator procedureCreator(sql);
 
-    // FIXME above std::cout << "test 7 passed (IN/OUT " << std::endl;
-    std::cout << "test 7 passed (IN/OUT proc skipped)" << std::endl;
+            string_holder sh;
+            indicator ind = i_ok;
+            procedure proc = (sql.prepare << "soci_test(:s)", use(sh, ind));
+            proc.execute(1);
+            assert(ind == i_null);
+        }
+    }
+    std::cout << "test 7 outnull passed" << std::endl;
 }
 
 // test bulk insert features
@@ -1196,6 +1219,8 @@ int main(int argc, char** argv)
         test5();
         test6();
         test7();
+        test7inout();
+        test7outnull();
         test8();
         test9();
         test10();

src/core/type-conversion.h

@@ -120,6 +120,12 @@ class conversion_use_type
 
     void convert_from_base()
     {
+        // NOTE:
+        // readOnly_ flag indicates that use_type object has been generated
+        // based on non-const object passed by user as input argument.
+        // For const objects, this is effectively no-op conversion.
+        // See standard_use_type::post_use() for more details.
+
         if (readOnly_ == false)
         {
             type_conversion<T>::from_base(

src/core/use-type.cpp

@@ -30,18 +30,26 @@ void standard_use_type::bind(statement_impl & st, int & position)
     }
 }
 
-void standard_use_type::pre_use()
+void standard_use_type::pre_use()   
 {
+    // Handle IN direction of parameters of SQL statements and procedures
     convert_to_base();
     backEnd_->pre_use(ind_);
 }
 
 void standard_use_type::post_use(bool gotData)
 {
+    // Handle OUT direction of IN/OUT parameters of stored procedures
     backEnd_->post_use(gotData, ind_);
+    convert_from_base();
 
-    // There is no need to call convert_from_base() here, the converted value
-    // wouldn't be used anyhow.
+    // IMPORTANT:
+    // This treatment of input ("use") parameter as output data sink may be 
+    // confusing, but it is necessary to store OUT data back in the same 
+    // object as IN, of IN/OUT parameter.
+    // As there is no symmetry for IN/OUT in SQL and there are no OUT/IN
+    // we do not perform convert_to_base() for output ("into") parameter.
+    // See conversion_use_type<T>::convert_from_base() for more details.
 }
 
 void standard_use_type::clean_up()