Diff: aws-iot/src/aws_iot_mqtt_client_unsubscribe.cpp

Revision:

0:cd5404401c2f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/aws-iot/src/aws_iot_mqtt_client_unsubscribe.cpp	Wed Apr 12 14:07:09 2017 +0200
@@ -0,0 +1,249 @@
+/*
+* Copyright 2015-2016 Amazon.com, Inc. or its affiliates. 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.
+* A copy of the License is located at
+*
+* http://aws.amazon.com/apache2.0
+*
+* or in the "license" file accompanying this file. This file is distributed
+* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+* express or implied. See the License for the specific language governing
+* permissions and limitations under the License.
+*/
+
+// Based on Eclipse Paho.
+/*******************************************************************************
+ * Copyright (c) 2014 IBM Corp.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * and Eclipse Distribution License v1.0 which accompany this distribution.
+ *
+ * The Eclipse Public License is available at
+ *    http://www.eclipse.org/legal/epl-v10.html
+ * and the Eclipse Distribution License is available at
+ *   http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * Contributors:
+ *    Ian Craggs - initial API and implementation and/or initial documentation
+ *******************************************************************************/
+
+/**
+ * @file aws_iot_mqtt_client_unsubscribe.c
+ * @brief MQTT client unsubscribe API definitions
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "aws_iot_mqtt_client_common_internal.h"
+
+/**
+  * Serializes the supplied unsubscribe data into the supplied buffer, ready for sending
+  * @param pTxBuf the raw buffer data, of the correct length determined by the remaining length field
+  * @param txBufLen the length in bytes of the data in the supplied buffer
+  * @param dup integer - the MQTT dup flag
+  * @param packetId integer - the MQTT packet identifier
+  * @param count - number of members in the topicFilters array
+  * @param pTopicNameList - array of topic filter names
+  * @param pTopicNameLenList - array of length of topic filter names in pTopicNameList
+  * @param pSerializedLen - the length of the serialized data
+  * @return IoT_Error_t indicating function execution status
+  */
+static IoT_Error_t _aws_iot_mqtt_serialize_unsubscribe(unsigned char *pTxBuf, size_t txBufLen,
+													   uint8_t dup, uint16_t packetId,
+													   uint32_t count, const char **pTopicNameList,
+													   uint16_t *pTopicNameLenList, uint32_t *pSerializedLen) {
+	unsigned char *ptr = pTxBuf;
+	uint32_t i = 0;
+	uint32_t rem_len = 2; /* packetId */
+	IoT_Error_t rc;
+	MQTTHeader header = {0};
+
+	FUNC_ENTRY;
+
+	for(i = 0; i < count; ++i) {
+		rem_len += (uint32_t) (pTopicNameLenList[i] + 2); /* topic + length */
+	}
+
+	if(aws_iot_mqtt_internal_get_final_packet_length_from_remaining_length(rem_len) > txBufLen) {
+		FUNC_EXIT_RC(MQTT_TX_BUFFER_TOO_SHORT_ERROR);
+	}
+
+	rc = aws_iot_mqtt_internal_init_header(&header, UNSUBSCRIBE, QOS1, dup, 0);
+	if(SUCCESS != rc) {
+		FUNC_EXIT_RC(rc);
+	}
+	aws_iot_mqtt_internal_write_char(&ptr, header.byte); /* write header */
+
+	ptr += aws_iot_mqtt_internal_write_len_to_buffer(ptr, rem_len); /* write remaining length */
+
+	aws_iot_mqtt_internal_write_uint_16(&ptr, packetId);
+
+	for(i = 0; i < count; ++i) {
+		aws_iot_mqtt_internal_write_utf8_string(&ptr, pTopicNameList[i], pTopicNameLenList[i]);
+	}
+
+	*pSerializedLen = (uint32_t) (ptr - pTxBuf);
+
+	FUNC_EXIT_RC(SUCCESS);
+}
+
+
+/**
+  * Deserializes the supplied (wire) buffer into unsuback data
+  * @param pPacketId returned integer - the MQTT packet identifier
+  * @param pRxBuf the raw buffer data, of the correct length determined by the remaining length field
+  * @param rxBufLen the length in bytes of the data in the supplied buffer
+  * @return IoT_Error_t indicating function execution status
+  */
+static IoT_Error_t _aws_iot_mqtt_deserialize_unsuback(uint16_t *pPacketId, unsigned char *pRxBuf, size_t rxBufLen) {
+	unsigned char type = 0;
+	unsigned char dup = 0;
+	IoT_Error_t rc;
+
+	FUNC_ENTRY;
+
+	rc = aws_iot_mqtt_internal_deserialize_ack(&type, &dup, pPacketId, pRxBuf, rxBufLen);
+	if(SUCCESS == rc && UNSUBACK != type) {
+		rc = FAILURE;
+	}
+
+	FUNC_EXIT_RC(rc);
+}
+
+/**
+ * @brief Unsubscribe to an MQTT topic.
+ *
+ * Called to send an unsubscribe message to the broker requesting removal of a subscription
+ * to an MQTT topic.
+ * @note Call is blocking.  The call returns after the receipt of the UNSUBACK control packet.
+ * This is the internal function which is called by the unsubscribe API to perform the operation.
+ * Not meant to be called directly as it doesn't do validations or client state changes
+ *
+ * @param pClient Reference to the IoT Client
+ * @param pTopicName Topic Name to publish to
+ * @param topicNameLen Length of the topic name
+ *
+ * @return An IoT Error Type defining successful/failed unsubscribe call
+ */
+static IoT_Error_t _aws_iot_mqtt_internal_unsubscribe(AWS_IoT_Client *pClient, const char *pTopicFilter,
+													  uint16_t topicFilterLen) {
+	/* No NULL checks because this is a static internal function */
+
+	TimerAWS timer;
+
+	uint16_t packet_id;
+	uint32_t serializedLen = 0;
+	uint32_t i = 0;
+	IoT_Error_t rc;
+	bool subscriptionExists = false;
+
+	FUNC_ENTRY;
+
+	/* Remove from message handler array */
+	for(i = 0; i < AWS_IOT_MQTT_NUM_SUBSCRIBE_HANDLERS; ++i) {
+		if(pClient->clientData.messageHandlers[i].topicName != NULL &&
+		   (strcmp(pClient->clientData.messageHandlers[i].topicName, pTopicFilter) == 0)) {
+			subscriptionExists = true;
+		}
+	}
+
+	if(false == subscriptionExists) {
+		FUNC_EXIT_RC(FAILURE);
+	}
+
+	init_timer(&timer);
+	countdown_ms(&timer, pClient->clientData.commandTimeoutMs);
+
+	rc = _aws_iot_mqtt_serialize_unsubscribe(pClient->clientData.writeBuf, pClient->clientData.writeBufSize, 0,
+											 aws_iot_mqtt_get_next_packet_id(pClient), 1, &pTopicFilter,
+											 &topicFilterLen, &serializedLen);
+	if(SUCCESS != rc) {
+		FUNC_EXIT_RC(rc);
+	}
+
+	/* send the unsubscribe packet */
+	rc = aws_iot_mqtt_internal_send_packet(pClient, serializedLen, &timer);
+	if(SUCCESS != rc) {
+		FUNC_EXIT_RC(rc);
+	}
+
+	rc = aws_iot_mqtt_internal_wait_for_read(pClient, UNSUBACK, &timer);
+	if(SUCCESS != rc) {
+		FUNC_EXIT_RC(rc);
+	}
+
+	rc = _aws_iot_mqtt_deserialize_unsuback(&packet_id, pClient->clientData.readBuf, pClient->clientData.readBufSize);
+	if(SUCCESS != rc) {
+		FUNC_EXIT_RC(rc);
+	}
+
+	/* Remove from message handler array */
+	for(i = 0; i < AWS_IOT_MQTT_NUM_SUBSCRIBE_HANDLERS; ++i) {
+		if(pClient->clientData.messageHandlers[i].topicName != NULL &&
+		   (strcmp(pClient->clientData.messageHandlers[i].topicName, pTopicFilter) == 0)) {
+			pClient->clientData.messageHandlers[i].topicName = NULL;
+			/* We don't want to break here, in case the same topic is registered
+             * with 2 callbacks. Unlikely scenario */
+		}
+	}
+
+	FUNC_EXIT_RC(SUCCESS);
+}
+
+/**
+ * @brief Unsubscribe to an MQTT topic.
+ *
+ * Called to send an unsubscribe message to the broker requesting removal of a subscription
+ * to an MQTT topic.
+ * @note Call is blocking.  The call returns after the receipt of the UNSUBACK control packet.
+ * This is the outer function which does the validations and calls the internal unsubscribe above
+ * to perform the actual operation. It is also responsible for client state changes
+ *
+ * @param pClient Reference to the IoT Client
+ * @param pTopicName Topic Name to publish to
+ * @param topicNameLen Length of the topic name
+ *
+ * @return An IoT Error Type defining successful/failed unsubscribe call
+ */
+IoT_Error_t aws_iot_mqtt_unsubscribe(AWS_IoT_Client *pClient, const char *pTopicFilter, uint16_t topicFilterLen) {
+	IoT_Error_t rc, unsubRc;
+	ClientState clientState;
+
+	if(NULL == pClient || NULL == pTopicFilter) {
+		return NULL_VALUE_ERROR;
+	}
+
+	if(!aws_iot_mqtt_is_client_connected(pClient)) {
+		return NETWORK_DISCONNECTED_ERROR;
+	}
+
+	clientState = aws_iot_mqtt_get_client_state(pClient);
+	if(CLIENT_STATE_CONNECTED_IDLE != clientState && CLIENT_STATE_CONNECTED_WAIT_FOR_CB_RETURN != clientState) {
+		return MQTT_CLIENT_NOT_IDLE_ERROR;
+	}
+
+	rc = aws_iot_mqtt_set_client_state(pClient, clientState, CLIENT_STATE_CONNECTED_UNSUBSCRIBE_IN_PROGRESS);
+	if(SUCCESS != rc) {
+		rc = aws_iot_mqtt_set_client_state(pClient, CLIENT_STATE_CONNECTED_UNSUBSCRIBE_IN_PROGRESS, clientState);
+		return rc;
+	}
+
+	unsubRc = _aws_iot_mqtt_internal_unsubscribe(pClient, pTopicFilter, topicFilterLen);
+
+	rc = aws_iot_mqtt_set_client_state(pClient, CLIENT_STATE_CONNECTED_UNSUBSCRIBE_IN_PROGRESS, clientState);
+	if(SUCCESS == unsubRc && SUCCESS != rc) {
+		unsubRc = rc;
+	}
+
+	return unsubRc;
+}
+
+#ifdef __cplusplus
+}
+#endif
+