Streamline query classifier API interface

- Only types of fixed size used in API interface
- The actual function return value specifies whether the parsing
  process succeeded, while "logical" return values are returned
  as out arguments.

The wrapper function currently ignores the function return value.

query_classifier/qc_dummy/qc_dummy.cc

@@ -15,72 +15,90 @@
 #include <maxscale/modules.h>
 #include <maxscale/query_classifier.h>
 
-qc_parse_result_t qc_parse(GWBUF* querybuf)
+int32_t qc_dummy_parse(GWBUF* querybuf, int32_t* pResult)
 {
-    return QC_QUERY_INVALID;
+    *pResult = QC_QUERY_INVALID;
+    return QC_RESULT_OK;
 }
 
-uint32_t qc_get_type(GWBUF* querybuf)
+int32_t qc_dummy_get_type(GWBUF* querybuf, uint32_t* pType_mask)
 {
-    return QUERY_TYPE_UNKNOWN;
+    *pType_mask = QUERY_TYPE_UNKNOWN;
+    return QC_RESULT_OK;
 }
 
-char** qc_get_table_names(GWBUF* querybuf, int* tblsize, bool fullnames)
+int32_t qc_dummy_get_table_names(GWBUF* querybuf, int32_t fullnames, char*** ppzNames, int32_t* pSize)
 {
-    *tblsize = 0;
-    return NULL;
+    *ppzNames = NULL;
+    *pSize = 0;
+    return QC_RESULT_OK;
 }
 
-char* qc_get_created_table_name(GWBUF* querybuf)
+int32_t qc_dummy_get_created_table_name(GWBUF* querybuf, char** pzName)
 {
-    return NULL;
+    *pzName = NULL;
+    return QC_RESULT_OK;
 }
 
-bool qc_is_drop_table_query(GWBUF* querybuf)
+int32_t qc_dummy_is_drop_table_query(GWBUF* querybuf, int32_t* pIs_drop_table)
 {
-    return false;
+    *pIs_drop_table = 0;
+    return QC_RESULT_OK;
 }
 
-bool qc_query_has_clause(GWBUF* buf)
+int32_t qc_dummy_query_has_clause(GWBUF* buf, int32_t *pHas_clause)
 {
-    return false;
+    *pHas_clause = 0;
+    return QC_RESULT_OK;
 }
 
-char** qc_get_database_names(GWBUF* querybuf, int* size)
+int32_t qc_dummy_get_database_names(GWBUF* querybuf, char*** ppzNames, int32_t* pSize)
 {
-    *size = 0;
-    return NULL;
+    *ppzNames = NULL;
+    *pSize = 0;
+    return QC_RESULT_OK;
 }
 
-qc_query_op_t qc_get_operation(GWBUF* querybuf)
+int32_t qc_dummy_get_operation(GWBUF* querybuf, int32_t* pOp)
 {
-    return QUERY_OP_UNDEFINED;
+    *pOp = QUERY_OP_UNDEFINED;
+    return QC_RESULT_OK;
 }
 
-char* qc_sqlite_get_prepare_name(GWBUF* query)
+int32_t qc_dummy_get_prepare_name(GWBUF* query, char** pzName)
 {
-    return NULL;
+    *pzName = NULL;
+    return QC_RESULT_OK;
 }
 
-qc_query_op_t qc_sqlite_get_prepare_operation(GWBUF* query)
+int32_t qc_dummy_get_prepare_operation(GWBUF* query, int32_t* pOp)
 {
-    return QUERY_OP_UNDEFINED;
+    *pOp = QUERY_OP_UNDEFINED;
+    return QC_RESULT_OK;
 }
 
-void qc_sqlite_get_field_info(GWBUF* query, const QC_FIELD_INFO** infos, size_t* n_infos)
+int32_t qc_dummy_get_field_info(GWBUF* query, const QC_FIELD_INFO** ppInfos, uint32_t* nInfos)
 {
-    *infos = NULL;
-    *n_infos = 0;
+    *ppInfos = NULL;
+    *nInfos = 0;
+    return QC_RESULT_OK;
 }
 
-bool qc_setup(const char* args)
+int32_t qc_dummy_get_function_info(GWBUF* query, const QC_FUNCTION_INFO** ppInfos, uint32_t* nInfos)
 {
-    return true;
+    *ppInfos = NULL;
+    *nInfos = 0;
+    return QC_RESULT_OK;
+}
+
+int32_t qc_dummy_setup(const char* args)
+{
+    return QC_RESULT_OK;
 }
 
 int qc_dummy_process_init(void)
 {
-    return 0;
+    return QC_RESULT_OK;
 }
 
 void qc_dummy_process_end(void)
@@ -89,7 +107,7 @@ void qc_dummy_process_end(void)
 
 int qc_dummy_thread_init(void)
 {
-    return 0;
+    return QC_RESULT_OK;
 }
 
 void qc_dummy_thread_end(void)
@@ -102,23 +120,24 @@ extern "C"
     {
         static QUERY_CLASSIFIER qc =
         {
-            qc_setup,
+            qc_dummy_setup,
             qc_dummy_process_init,
             qc_dummy_process_end,
             qc_dummy_thread_init,
             qc_dummy_thread_end,
-            qc_parse,
-            qc_get_type,
-            qc_get_operation,
-            qc_get_created_table_name,
-            qc_is_drop_table_query,
-            qc_get_table_names,
+            qc_dummy_parse,
+            qc_dummy_get_type,
+            qc_dummy_get_operation,
+            qc_dummy_get_created_table_name,
+            qc_dummy_is_drop_table_query,
+            qc_dummy_get_table_names,
             NULL,
-            qc_query_has_clause,
-            qc_get_database_names,
-            qc_get_prepare_name,
-            qc_get_prepare_operation,
-            qc_get_field_info,
+            qc_dummy_query_has_clause,
+            qc_dummy_get_database_names,
+            qc_dummy_get_prepare_name,
+            qc_dummy_get_prepare_operation,
+            qc_dummy_get_field_info,
+            qc_dummy_get_function_info,
         };
 
         static MXS_MODULE info =