Fix bugs
[platform/core/uifw/stt.git] / client / stt.c
index 19e7cb1..fa4dd9c 100644 (file)
@@ -1,5 +1,5 @@
 /*
-*  Copyright (c) 2011-2014 Samsung Electronics Co., Ltd All Rights Reserved
+*  Copyright (c) 2011-2016 Samsung Electronics Co., Ltd All Rights Reserved
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
@@ -329,27 +329,18 @@ int stt_create(stt_h* stt)
 
 int stt_destroy(stt_h stt)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       SLOG(LOG_DEBUG, TAG_STTC, "===== Destroy STT");
-
-       if (NULL == stt) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input handle is null");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
-               return STT_ERROR_INVALID_PARAMETER;
-       }
+       SLOG(LOG_DEBUG, TAG_STTC, "===== Destroy STT");
 
        /* check used callback */
        if (0 != stt_client_get_use_callback(client)) {
@@ -421,25 +412,21 @@ bool __stt_config_supported_engine_cb(const char* engine_id, const char* engine_
 
 int stt_foreach_supported_engines(stt_h stt, stt_supported_engine_cb callback, void* user_data)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       SLOG(LOG_DEBUG, TAG_STTC, "===== Foreach Supported engine");
-
-       if (NULL == stt || NULL == callback) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
+       SLOG(LOG_DEBUG, TAG_STTC, "===== Foreach Supported engine");
 
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (NULL == callback) {
+               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
                return STT_ERROR_INVALID_PARAMETER;
        }
 
@@ -469,22 +456,21 @@ int stt_foreach_supported_engines(stt_h stt, stt_supported_engine_cb callback, v
 
 int stt_get_engine(stt_h stt, char** engine_id)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
-
-       SLOG(LOG_DEBUG, TAG_STTC, "===== Get current engine");
-
-       if (NULL == stt || NULL == engine_id) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
+       if (0 != __stt_check_privilege()) {
+               return STT_ERROR_PERMISSION_DENIED;
+       }
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
+       SLOG(LOG_DEBUG, TAG_STTC, "===== Get current engine");
 
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (NULL == engine_id) {
+               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
                return STT_ERROR_INVALID_PARAMETER;
        }
 
@@ -517,25 +503,21 @@ int stt_get_engine(stt_h stt, char** engine_id)
 
 int stt_set_engine(stt_h stt, const char* engine_id)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       SLOG(LOG_DEBUG, TAG_STTC, "===== Set current engine");
-
-       if (NULL == stt || NULL == engine_id) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
+       SLOG(LOG_DEBUG, TAG_STTC, "===== Set current engine");
 
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (NULL == engine_id) {
+               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
                return STT_ERROR_INVALID_PARAMETER;
        }
 
@@ -559,25 +541,21 @@ int stt_set_engine(stt_h stt, const char* engine_id)
 
 int stt_set_credential(stt_h stt, const char* credential)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       SLOG(LOG_DEBUG, TAG_STTC, "===== Set credential");
-
-       if (NULL == stt || NULL == credential) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL, stt(%s), credential(%a)", stt, credential);
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
+       SLOG(LOG_DEBUG, TAG_STTC, "===== Set credential");
 
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (NULL == credential) {
+               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
                return STT_ERROR_INVALID_PARAMETER;
        }
 
@@ -598,7 +576,6 @@ int stt_set_credential(stt_h stt, const char* credential)
 int stt_set_private_data(stt_h stt, const char* key, const char* data)
 {
        stt_client_s* client = NULL;
-
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
@@ -651,7 +628,6 @@ int stt_set_private_data(stt_h stt, const char* key, const char* data)
 int stt_get_private_data(stt_h stt, const char* key, char** data)
 {
        stt_client_s* client = NULL;
-
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
@@ -802,20 +778,14 @@ static Eina_Bool __stt_connect_daemon(void *data)
 
 int stt_prepare(stt_h stt)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       SLOG(LOG_DEBUG, TAG_STTC, "===== Prepare STT");
-
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
@@ -835,23 +805,19 @@ int stt_prepare(stt_h stt)
 
 int stt_unprepare(stt_h stt)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       SLOG(LOG_DEBUG, TAG_STTC, "===== Unprepare STT");
-
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
+       SLOG(LOG_DEBUG, TAG_STTC, "===== Unprepare STT");
+
        /* check state */
        if (client->current_state != STT_STATE_READY) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Invalid State: Current state(%d) is not 'READY'", client->current_state);
@@ -925,25 +891,21 @@ bool __stt_config_supported_language_cb(const char* engine_id, const char* langu
 
 int stt_foreach_supported_languages(stt_h stt, stt_supported_language_cb callback, void* user_data)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       SLOG(LOG_DEBUG, TAG_STTC, "===== Foreach Supported Language");
-
-       if (NULL == stt || NULL == callback) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
+       SLOG(LOG_DEBUG, TAG_STTC, "===== Foreach Supported Language");
 
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (NULL == callback) {
+               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
                return STT_ERROR_INVALID_PARAMETER;
        }
 
@@ -989,26 +951,24 @@ int stt_foreach_supported_languages(stt_h stt, stt_supported_language_cb callbac
 
 int stt_get_default_language(stt_h stt, char** language)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
+       if (0 != __stt_check_handle(stt, &client)) {
+               return STT_ERROR_INVALID_PARAMETER;
+       }
 
        SLOG(LOG_DEBUG, TAG_STTC, "===== Get Default Language");
 
-       if (NULL == stt || NULL == language) {
+       if (NULL == language) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
-               return STT_ERROR_INVALID_PARAMETER;
-       }
-
        int ret = 0;
        ret = stt_config_mgr_get_default_language(language);
        ret = __stt_convert_config_error_code(ret);
@@ -1026,21 +986,19 @@ int stt_get_default_language(stt_h stt, char** language)
 
 int stt_get_state(stt_h stt, stt_state_e* state)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       if (NULL == stt || NULL == state) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Get state : A handle is not valid");
+       if (NULL == state) {
+               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
                return STT_ERROR_INVALID_PARAMETER;
        }
 
@@ -1059,14 +1017,18 @@ int stt_get_state(stt_h stt, stt_state_e* state)
 
 int stt_get_error_message(stt_h stt, char** err_msg)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
+       if (0 != __stt_check_handle(stt, &client)) {
+               return STT_ERROR_INVALID_PARAMETER;
+       }
 
-       if (NULL == stt || NULL == err_msg) {
+       if (NULL == err_msg) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
                return STT_ERROR_INVALID_PARAMETER;
        }
@@ -1076,12 +1038,6 @@ int stt_get_error_message(stt_h stt, char** err_msg)
                return STT_ERROR_OPERATION_FAILED;
        }
 
-       stt_client_s* client = stt_client_get(stt);
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Get error msg : A handle is not valid");
-               return STT_ERROR_INVALID_PARAMETER;
-       }
-
        if (NULL != client->err_msg) {
                *err_msg = strdup(client->err_msg);
                SLOG(LOG_DEBUG, TAG_STTC, "[SUCCESS] Error msg (%s)", *err_msg);
@@ -1097,21 +1053,19 @@ int stt_get_error_message(stt_h stt, char** err_msg)
 
 int stt_is_recognition_type_supported(stt_h stt, const char* type, bool* support)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       if (NULL == stt || NULL == type || NULL == support) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not valid");
+       if (NULL == type || NULL == support) {
+               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
                return STT_ERROR_INVALID_PARAMETER;
        }
 
@@ -1149,21 +1103,14 @@ int stt_is_recognition_type_supported(stt_h stt, const char* type, bool* support
 
 int stt_set_silence_detection(stt_h stt, stt_option_silence_detection_e type)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       if (NULL == stt) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
-               return STT_ERROR_INVALID_PARAMETER;
-       }
-
-       stt_client_s* client = stt_client_get(stt);
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Get state : A handle is not valid");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
@@ -1189,16 +1136,20 @@ int stt_set_silence_detection(stt_h stt, stt_option_silence_detection_e type)
 
 int stt_set_start_sound(stt_h stt, const char* filename)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
+       if (0 != __stt_check_handle(stt, &client)) {
+               return STT_ERROR_INVALID_PARAMETER;
+       }
 
        SLOG(LOG_DEBUG, TAG_STTC, "===== STT SET START SOUND");
 
-       if (NULL == stt || NULL == filename) {
+       if (NULL == filename) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
                return STT_ERROR_INVALID_PARAMETER;
        }
@@ -1208,12 +1159,6 @@ int stt_set_start_sound(stt_h stt, const char* filename)
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Get state : A handle is not valid");
-               return STT_ERROR_INVALID_PARAMETER;
-       }
-
        /* check state */
        if (client->current_state != STT_STATE_READY) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Invalid State: Current state(%d) is not READY", client->current_state);
@@ -1248,26 +1193,18 @@ int stt_set_start_sound(stt_h stt, const char* filename)
 
 int stt_unset_start_sound(stt_h stt)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       SLOG(LOG_DEBUG, TAG_STTC, "===== STT UNSET START SOUND");
-
-       if (NULL == stt) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
-
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Get state : A handle is not valid");
-               return STT_ERROR_INVALID_PARAMETER;
-       }
+       SLOG(LOG_DEBUG, TAG_STTC, "===== STT UNSET START SOUND");
 
        /* check state */
        if (client->current_state != STT_STATE_READY) {
@@ -1303,16 +1240,20 @@ int stt_unset_start_sound(stt_h stt)
 
 int stt_set_stop_sound(stt_h stt, const char* filename)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
+       if (0 != __stt_check_handle(stt, &client)) {
+               return STT_ERROR_INVALID_PARAMETER;
+       }
 
        SLOG(LOG_DEBUG, TAG_STTC, "===== STT SET STOP SOUND");
 
-       if (NULL == stt || NULL == filename) {
+       if (NULL == filename) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
                return STT_ERROR_INVALID_PARAMETER;
        }
@@ -1322,13 +1263,6 @@ int stt_set_stop_sound(stt_h stt, const char* filename)
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
-
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Get state : A handle is not valid");
-               return STT_ERROR_INVALID_PARAMETER;
-       }
-
        /* check state */
        if (client->current_state != STT_STATE_READY) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Invalid State: Current state(%d) is not READY", client->current_state);
@@ -1363,26 +1297,18 @@ int stt_set_stop_sound(stt_h stt, const char* filename)
 
 int stt_unset_stop_sound(stt_h stt)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       SLOG(LOG_DEBUG, TAG_STTC, "===== STT UNSET STOP SOUND");
-
-       if (NULL == stt) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
-
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Get state : A handle is not valid");
-               return STT_ERROR_INVALID_PARAMETER;
-       }
+       SLOG(LOG_DEBUG, TAG_STTC, "===== STT UNSET STOP SOUND");
 
        /* check state */
        if (client->current_state != STT_STATE_READY) {
@@ -1418,25 +1344,18 @@ int stt_unset_stop_sound(stt_h stt)
 
 int stt_start(stt_h stt, const char* language, const char* type)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       SLOG(LOG_DEBUG, TAG_STTC, "===== STT START");
-
-       if (NULL == stt) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
-               return STT_ERROR_INVALID_PARAMETER;
-       }
+       SLOG(LOG_DEBUG, TAG_STTC, "===== STT START");
 
        /* check state */
        if (client->current_state != STT_STATE_READY) {
@@ -1446,7 +1365,7 @@ int stt_start(stt_h stt, const char* language, const char* type)
 
        if (STT_INTERNAL_STATE_NONE != client->internal_state) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Invalid State : Internal state is NOT none : %d", client->internal_state);
-               return STT_ERROR_INVALID_STATE;
+               return STT_ERROR_IN_PROGRESS_TO_RECORDING;
        }
 
        int ret = -1;
@@ -1466,54 +1385,6 @@ int stt_start(stt_h stt, const char* language, const char* type)
                temp = strdup(language);
        }
 
-#if 0
-       ret = -1;
-       /* do request */
-       int count = 0;
-       while (0 != ret) {
-               ret = stt_dbus_request_start(client->uid, temp, type, client->silence, appid);
-               if (0 > ret) {
-                       /* Failure */
-                       if (STT_ERROR_TIMED_OUT != ret) {
-                               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Fail to start : %s", __stt_get_error_code(ret));
-                               if (NULL != temp)       free(temp);
-                               return ret;
-                       } else {
-                               SLOG(LOG_WARN, TAG_STTC, "[WARNING] retry to start");
-                               usleep(10000);
-                               count++;
-                               if (STT_RETRY_COUNT == count) {
-                                       SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Fail to request");
-                                       if (NULL != temp)       free(temp);
-                                       return ret;
-                               }
-                       }
-               } else {
-                       /* Success */
-                       if (NULL != temp)       free(temp);
-
-                       if (STT_RESULT_STATE_DONE == ret) {
-                               SLOG(LOG_DEBUG, TAG_STTC, "[SUCCESS] Start is done : %d", ret);
-                               client->before_state = client->current_state;
-                               client->current_state = STT_STATE_RECORDING;
-
-                               if (NULL != client->state_changed_cb) {
-                                       ecore_main_loop_thread_safe_call_async(__stt_notify_state_changed, client);
-                               } else {
-                                       SLOG(LOG_WARN, TAG_STTC, "[WARNING] State changed callback is null");
-                               }
-                       } else if (STT_RESULT_STATE_NOT_DONE == ret) {
-                               SLOG(LOG_DEBUG, TAG_STTC, "[SUCCESS] Start is not done : %d", ret);
-                               client->internal_state = STT_INTERNAL_STATE_STARTING;
-                       } else {
-                               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Invalid result : %d", ret);
-                       }
-
-                       ret = STT_ERROR_NONE;
-                       break;
-               }
-       }
-#else
        if (true == client->credential_needed && NULL == client->credential) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Do not have app credential for this engine(%s)", client->current_engine_id);
                return STT_ERROR_PERMISSION_DENIED;
@@ -1528,7 +1399,7 @@ int stt_start(stt_h stt, const char* language, const char* type)
        }
 
        if (NULL != temp)       free(temp);
-#endif
+
        SLOG(LOG_DEBUG, TAG_STTC, "=====");
        SLOG(LOG_DEBUG, TAG_STTC, " ");
 
@@ -1537,25 +1408,18 @@ int stt_start(stt_h stt, const char* language, const char* type)
 
 int stt_stop(stt_h stt)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       SLOG(LOG_DEBUG, TAG_STTC, "===== STT STOP");
-
-       if (NULL == stt) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
-               return STT_ERROR_INVALID_PARAMETER;
-       }
+       SLOG(LOG_DEBUG, TAG_STTC, "===== STT STOP");
 
        /* check state */
        if (client->current_state != STT_STATE_RECORDING) {
@@ -1563,62 +1427,26 @@ int stt_stop(stt_h stt)
                return STT_ERROR_INVALID_STATE;
        }
 
-       if (STT_INTERNAL_STATE_NONE != client->internal_state) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Invalid State : Internal state is NOT none : %d", client->internal_state);
-               return STT_ERROR_INVALID_STATE;
+       if (STT_INTERNAL_STATE_STARTING == client->internal_state) {
+               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Invalid State : Internal state is STARTING : %d", client->internal_state);
+               return STT_ERROR_IN_PROGRESS_TO_RECORDING;
+       } else if (STT_INTERNAL_STATE_CANCELING == client->internal_state) {
+               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Invalid State : Internal state is CANCELING : %d", client->internal_state);
+               return STT_ERROR_IN_PROGRESS_TO_READY;
+       } else if (STT_INTERNAL_STATE_STOPPING == client->internal_state) {
+               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Invalid State : Internal state is STOPPING : %d", client->internal_state);
+               return STT_ERROR_IN_PROGRESS_TO_PROCESSING;
        }
-#if 0
-       int ret = -1;
-       /* do request */
-       int count = 0;
-       while (0 != ret) {
-               ret = stt_dbus_request_stop(client->uid);
-               if (0 > ret) {
-                       /* Failure */
-                       if (STT_ERROR_TIMED_OUT != ret) {
-                               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Fail to stop : %s", __stt_get_error_code(ret));
-                               return ret;
-                       } else {
-                               SLOG(LOG_WARN, TAG_STTC, "[WARNING] retry stop");
-                               usleep(10000);
-                               count++;
-                               if (STT_RETRY_COUNT == count) {
-                                       SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Fail to request");
-                                       return ret;
-                               }
-                       }
-               } else {
-                       if (STT_RESULT_STATE_DONE == ret) {
-                               SLOG(LOG_DEBUG, TAG_STTC, "[SUCCESS] Stop is done : %d", ret);
-                               client->before_state = client->current_state;
-                               client->current_state = STT_STATE_PROCESSING;
-
-                               if (NULL != client->state_changed_cb) {
-                                       ecore_main_loop_thread_safe_call_async(__stt_notify_state_changed, client);
-                                       SLOG(LOG_DEBUG, TAG_STTC, "State changed callback is called");
-                               } else {
-                                       SLOG(LOG_WARN, TAG_STTC, "[WARNING] State changed callback is null");
-                               }
-                       } else if (STT_RESULT_STATE_NOT_DONE == ret) {
-                               SLOG(LOG_DEBUG, TAG_STTC, "[SUCCESS] Stop is not done : %d", ret);
-                               client->internal_state = STT_INTERNAL_STATE_STOPING;
-                       } else {
-                               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Invalid result : %d", ret);
-                       }
-                       ret = STT_ERROR_NONE;
-                       break;
-               }
-       }
-#else
+
        int ret = stt_dbus_request_stop(client->uid);
 
        if (0 != ret) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Fail to stop : %s", __stt_get_error_code(ret));
        } else {
                SLOG(LOG_DEBUG, TAG_STTC, "[SUCCESS] Stop is successful but not done");
-               client->internal_state = STT_INTERNAL_STATE_STOPING;
+               client->internal_state = STT_INTERNAL_STATE_STOPPING;
        }
-#endif
+
        SLOG(LOG_DEBUG, TAG_STTC, "=====");
        SLOG(LOG_DEBUG, TAG_STTC, " ");
 
@@ -1628,27 +1456,18 @@ int stt_stop(stt_h stt)
 
 int stt_cancel(stt_h stt)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       SLOG(LOG_DEBUG, TAG_STTC, "===== STT CANCEL");
-
-       if (NULL == stt) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input handle is null");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
-               return STT_ERROR_INVALID_PARAMETER;
-       }
+       SLOG(LOG_DEBUG, TAG_STTC, "===== STT CANCEL");
 
        /* check state */
        if (STT_STATE_RECORDING != client->current_state && STT_STATE_PROCESSING != client->current_state) {
@@ -1656,47 +1475,17 @@ int stt_cancel(stt_h stt)
                return STT_ERROR_INVALID_STATE;
        }
 
-       if (STT_INTERNAL_STATE_NONE != client->internal_state) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Invalid State : Internal state is NOT none : %d", client->internal_state);
-               return STT_ERROR_INVALID_STATE;
+       if (STT_INTERNAL_STATE_STARTING == client->internal_state) {
+               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Invalid State : Internal state is STARTING : %d", client->internal_state);
+               return STT_ERROR_IN_PROGRESS_TO_RECORDING;
+       } else if (STT_INTERNAL_STATE_STOPPING == client->internal_state) {
+               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Invalid State : Internal state is STOPPING : %d", client->internal_state);
+               return STT_ERROR_IN_PROGRESS_TO_PROCESSING;
+       } else if (STT_INTERNAL_STATE_CANCELING == client->internal_state) {
+               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Invalid State : Internal state is CANCELING : %d", client->internal_state);
+               return STT_ERROR_IN_PROGRESS_TO_READY;
        }
-#if 0
-       int ret = -1;
-       /* do request */
-       int count = 0;
-       while (0 != ret) {
-               ret = stt_dbus_request_cancel(client->uid);
-               if (0 != ret) {
-                       /* Failure */
-                       if (STT_ERROR_TIMED_OUT != ret) {
-                               SLOG(LOG_DEBUG, TAG_STTC, "[ERROR] Fail to cancel : %s", __stt_get_error_code(ret));
-                               return ret;
-                       } else {
-                               SLOG(LOG_WARN, TAG_STTC, "[WARNING] retry");
-                               usleep(10000);
-                               count++;
-                               if (STT_RETRY_COUNT == count) {
-                                       SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Fail to request");
-                                       return ret;
-                               }
-                       }
-               } else {
-                       SLOG(LOG_DEBUG, TAG_STTC, "[SUCCESS]");
-
-                       client->before_state = client->current_state;
-                       client->current_state = STT_STATE_READY;
 
-                       if (NULL != client->state_changed_cb) {
-                               ecore_main_loop_thread_safe_call_async(__stt_notify_state_changed, client);
-                               SLOG(LOG_DEBUG, TAG_STTC, "State changed callback is called");
-                       } else {
-                               SLOG(LOG_WARN, TAG_STTC, "[WARNING] State changed callback is null");
-                       }
-                       ret = STT_ERROR_NONE;
-                       break;
-               }
-       }
-#else
        int ret = stt_dbus_request_cancel(client->uid);
        if (0 != ret) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Fail to cancel : %s", __stt_get_error_code(ret));
@@ -1704,7 +1493,7 @@ int stt_cancel(stt_h stt)
                SLOG(LOG_DEBUG, TAG_STTC, "[SUCCESS] Cancel is successful but not done");
                client->internal_state = STT_INTERNAL_STATE_CANCELING;
        }
-#endif
+
        SLOG(LOG_DEBUG, TAG_STTC, "=====");
        SLOG(LOG_DEBUG, TAG_STTC, " ");
 
@@ -1734,23 +1523,19 @@ int __stt_cb_set_volume(int uid, float volume)
 
 int stt_get_recording_volume(stt_h stt, float* volume)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       if (NULL == stt || NULL == volume) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (NULL == volume) {
+               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Input parameter is NULL");
                return STT_ERROR_INVALID_PARAMETER;
        }
 
@@ -1789,12 +1574,16 @@ bool __stt_result_time_cb(int index, int event, const char* text, long start_tim
 
 int stt_foreach_detailed_result(stt_h stt, stt_result_time_cb callback, void* user_data)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
+       if (0 != __stt_check_handle(stt, &client)) {
+               return STT_ERROR_INVALID_PARAMETER;
+       }
 
        SLOG(LOG_DEBUG, TAG_STTC, "===== STT FOREACH DETAILED RESULT");
 
@@ -1803,14 +1592,6 @@ int stt_foreach_detailed_result(stt_h stt, stt_result_time_cb callback, void* us
                return STT_ERROR_INVALID_PARAMETER;
        }
 
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Fail : A handle is not valid");
-               return STT_ERROR_INVALID_PARAMETER;
-       }
-
        client->result_time_cb = callback;
        client->result_time_user_data = user_data;
 
@@ -1903,7 +1684,7 @@ static void __stt_notify_state_changed(void *data)
        if (STT_INTERNAL_STATE_STARTING == client->internal_state && STT_STATE_RECORDING == client->current_state) {
                client->internal_state = STT_INTERNAL_STATE_NONE;
                SLOG(LOG_DEBUG, TAG_STTC, "Internal state change to NONE");
-       } else if (STT_INTERNAL_STATE_STOPING == client->internal_state && STT_STATE_PROCESSING == client->current_state) {
+       } else if (STT_INTERNAL_STATE_STOPPING == client->internal_state && STT_STATE_PROCESSING == client->current_state) {
                client->internal_state = STT_INTERNAL_STATE_NONE;
                SLOG(LOG_DEBUG, TAG_STTC, "Internal state change to NONE");
        } else if (STT_INTERNAL_STATE_CANCELING == client->internal_state && STT_STATE_READY == client->current_state) {
@@ -2065,23 +1846,19 @@ int __stt_cb_set_state(int uid, int state)
 
 int stt_set_recognition_result_cb(stt_h stt, stt_recognition_result_cb callback, void* user_data)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       if (stt == NULL || callback == NULL)
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
+       }
 
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (callback == NULL)
                return STT_ERROR_INVALID_PARAMETER;
-       }
 
        if (STT_STATE_CREATED != client->current_state) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Current state(%d) is not 'Created'", client->current_state);
@@ -2096,21 +1873,14 @@ int stt_set_recognition_result_cb(stt_h stt, stt_recognition_result_cb callback,
 
 int stt_unset_recognition_result_cb(stt_h stt)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       if (NULL == stt)
-               return STT_ERROR_INVALID_PARAMETER;
-
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
@@ -2127,23 +1897,19 @@ int stt_unset_recognition_result_cb(stt_h stt)
 
 int stt_set_state_changed_cb(stt_h stt, stt_state_changed_cb callback, void* user_data)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       if (NULL == stt || NULL == callback)
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
+       }
 
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (NULL == callback)
                return STT_ERROR_INVALID_PARAMETER;
-       }
 
        if (STT_STATE_CREATED != client->current_state) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Current state(%d) is not 'Created'", client->current_state);
@@ -2158,21 +1924,14 @@ int stt_set_state_changed_cb(stt_h stt, stt_state_changed_cb callback, void* use
 
 int stt_unset_state_changed_cb(stt_h stt)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       if (NULL == stt)
-               return STT_ERROR_INVALID_PARAMETER;
-
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
@@ -2189,23 +1948,19 @@ int stt_unset_state_changed_cb(stt_h stt)
 
 int stt_set_error_cb(stt_h stt, stt_error_cb callback, void* user_data)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       if (NULL == stt || NULL == callback)
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
+       }
 
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (NULL == callback)
                return STT_ERROR_INVALID_PARAMETER;
-       }
 
        if (STT_STATE_CREATED != client->current_state) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Current state(%d) is not 'Created'", client->current_state);
@@ -2220,21 +1975,14 @@ int stt_set_error_cb(stt_h stt, stt_error_cb callback, void* user_data)
 
 int stt_unset_error_cb(stt_h stt)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       if (NULL == stt)
-               return STT_ERROR_INVALID_PARAMETER;
-
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
@@ -2251,23 +1999,19 @@ int stt_unset_error_cb(stt_h stt)
 
 int stt_set_default_language_changed_cb(stt_h stt, stt_default_language_changed_cb callback, void* user_data)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       if (NULL == stt || NULL == callback)
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
+       }
 
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (NULL == callback)
                return STT_ERROR_INVALID_PARAMETER;
-       }
 
        if (STT_STATE_CREATED != client->current_state) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Current state(%d) is not 'Created'", client->current_state);
@@ -2282,21 +2026,14 @@ int stt_set_default_language_changed_cb(stt_h stt, stt_default_language_changed_
 
 int stt_unset_default_language_changed_cb(stt_h stt)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       if (NULL == stt)
-               return STT_ERROR_INVALID_PARAMETER;
-
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }
 
@@ -2313,23 +2050,19 @@ int stt_unset_default_language_changed_cb(stt_h stt)
 
 int stt_set_engine_changed_cb(stt_h stt, stt_engine_changed_cb callback, void* user_data)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       if (NULL == stt || NULL == callback)
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
+       }
 
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (NULL == callback)
                return STT_ERROR_INVALID_PARAMETER;
-       }
 
        if (STT_STATE_CREATED != client->current_state) {
                SLOG(LOG_ERROR, TAG_STTC, "[ERROR] Current state(%d) is not 'Created'", client->current_state);
@@ -2344,21 +2077,14 @@ int stt_set_engine_changed_cb(stt_h stt, stt_engine_changed_cb callback, void* u
 
 int stt_unset_engine_changed_cb(stt_h stt)
 {
+       stt_client_s* client = NULL;
        if (0 != __stt_get_feature_enabled()) {
                return STT_ERROR_NOT_SUPPORTED;
        }
        if (0 != __stt_check_privilege()) {
                return STT_ERROR_PERMISSION_DENIED;
        }
-
-       if (NULL == stt)
-               return STT_ERROR_INVALID_PARAMETER;
-
-       stt_client_s* client = stt_client_get(stt);
-
-       /* check handle */
-       if (NULL == client) {
-               SLOG(LOG_ERROR, TAG_STTC, "[ERROR] A handle is not available");
+       if (0 != __stt_check_handle(stt, &client)) {
                return STT_ERROR_INVALID_PARAMETER;
        }