MXS-852: Add support for text protocol prepared statements

When a statement is being prepared, the type and name of the statement is
stored in the router session. If the name of a statement to be executed is
found in the map, the query type that stored in the map is used.

server/modules/routing/readwritesplit/rwsplit_ps.cc

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2020-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#include "readwritesplit.hh"
+
+#include <maxscale/alloc.h>
+#include <maxscale/query_classifier.h>
+
+std::string extract_text_ps_id(GWBUF* buffer)
+{
+    std::string rval;
+    char* name = qc_get_prepare_name(buffer);
+
+    if (name)
+    {
+        rval = name;
+        MXS_FREE(name);
+    }
+
+    return rval;
+}
+
+void store_text_ps(ROUTER_CLIENT_SES* rses, std::string id, GWBUF* buffer)
+{
+    GWBUF* stmt = qc_get_preparable_stmt(buffer);
+    ss_dassert(stmt);
+
+    uint32_t type = qc_get_type_mask(stmt);
+    ss_dassert((type & (QUERY_TYPE_PREPARE_STMT | QUERY_TYPE_PREPARE_NAMED_STMT)) == 0);
+
+    rses->ps_text[id] = type;
+}
+
+void erase_text_ps(ROUTER_CLIENT_SES* rses, std::string id)
+{
+    rses->ps_text.erase(id);
+}
+
+bool get_text_ps_type(ROUTER_CLIENT_SES* rses, GWBUF* buffer, uint32_t* out)
+{
+    bool rval = false;
+    char* name = qc_get_prepare_name(buffer);
+
+    if (name)
+    {
+        TextPSMap::iterator it = rses->ps_text.find(name);
+
+        if (it != rses->ps_text.end())
+        {
+            *out = it->second;
+            rval = true;
+        }
+
+        MXS_FREE(name);
+    }
+
+    return rval;
+}