File content as of revision 38:a05929a75111:

// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

/** @file iothub_client_ll.h
*	@brief	 APIs that allow a user (usually a device) to communicate
*		     with an Azure IoTHub.
*
*	@details IoTHubClient_LL is a module that allows a user (usually a
*			 device) to communicate with an Azure IoTHub. It can send events
*			 and receive messages. At any given moment in time there can only
*			 be at most 1 message callback function.
*			 
*			 This API surface contains a set of APIs that allows the user to
*			 interact with the lower layer portion of the IoTHubClient. These APIs
*			 contain @c _LL_ in their name, but retain the same functionality like the
*			 @c IoTHubClient_... APIs, with one difference. If the @c _LL_ APIs are
*			 used then the user is responsible for scheduling when the actual work done
*			 by the IoTHubClient happens (when the data is sent/received on/from the wire).
*			 This is useful for constrained devices where spinning a separate thread is
*			 often not desired.
*/

#ifndef IOTHUB_CLIENT_LL_H
#define IOTHUB_CLIENT_LL_H

#include "azure_c_shared_utility/agenttime.h"
#include "azure_c_shared_utility/macro_utils.h"
#include "azure_c_shared_utility/xio.h"
#include "azure_c_shared_utility/doublylinkedlist.h"
#include "iothub_message.h"

#ifdef __cplusplus
extern "C"
{
#endif

#define IOTHUB_CLIENT_RESULT_VALUES       \
    IOTHUB_CLIENT_OK,                     \
    IOTHUB_CLIENT_INVALID_ARG,            \
    IOTHUB_CLIENT_ERROR,                  \
    IOTHUB_CLIENT_INVALID_SIZE,           \
    IOTHUB_CLIENT_INDEFINITE_TIME         \

/** @brief Enumeration specifying the status of calls to various APIs in this module.
*/
DEFINE_ENUM(IOTHUB_CLIENT_RESULT, IOTHUB_CLIENT_RESULT_VALUES);

#define IOTHUB_CLIENT_CONFIRMATION_RESULT_VALUES     \
    IOTHUB_CLIENT_CONFIRMATION_OK,                   \
    IOTHUB_CLIENT_CONFIRMATION_BECAUSE_DESTROY,      \
    IOTHUB_CLIENT_CONFIRMATION_MESSAGE_TIMEOUT,      \
    IOTHUB_CLIENT_CONFIRMATION_ERROR                 \

/** @brief Enumeration passed in by the IoT Hub when the event confirmation  
*		   callback is invoked to indicate status of the event processing in  
*		   the hub.
*/
DEFINE_ENUM(IOTHUB_CLIENT_CONFIRMATION_RESULT, IOTHUB_CLIENT_CONFIRMATION_RESULT_VALUES);

#define IOTHUB_CLIENT_STATUS_VALUES       \
    IOTHUB_CLIENT_SEND_STATUS_IDLE,       \
    IOTHUB_CLIENT_SEND_STATUS_BUSY        \

/** @brief Enumeration returned by the ::IoTHubClient_LL_GetSendStatus  
*		   API to indicate the current sending status of the IoT Hub client.
*/
DEFINE_ENUM(IOTHUB_CLIENT_STATUS, IOTHUB_CLIENT_STATUS_VALUES);

#define TRANSPORT_TYPE_VALUES \
    TRANSPORT_LL, /*LL comes from "LowLevel" */ \
    TRANSPORT_THREADED

DEFINE_ENUM(TRANSPORT_TYPE, TRANSPORT_TYPE_VALUES);

#define IOTHUBMESSAGE_DISPOSITION_RESULT_VALUES \
    IOTHUBMESSAGE_ACCEPTED, \
    IOTHUBMESSAGE_REJECTED, \
    IOTHUBMESSAGE_ABANDONED

/** @brief Enumeration returned by the callback which is invoked whenever the  
*		   IoT Hub sends a message to the device.
*/
DEFINE_ENUM(IOTHUBMESSAGE_DISPOSITION_RESULT, IOTHUBMESSAGE_DISPOSITION_RESULT_VALUES);

typedef struct IOTHUB_CLIENT_LL_HANDLE_DATA_TAG* IOTHUB_CLIENT_LL_HANDLE;
typedef void(*IOTHUB_CLIENT_EVENT_CONFIRMATION_CALLBACK)(IOTHUB_CLIENT_CONFIRMATION_RESULT result, void* userContextCallback);
typedef IOTHUBMESSAGE_DISPOSITION_RESULT (*IOTHUB_CLIENT_MESSAGE_CALLBACK_ASYNC)(IOTHUB_MESSAGE_HANDLE message, void* userContextCallback);
typedef const void*(*IOTHUB_CLIENT_TRANSPORT_PROVIDER)(void);

/** @brief	This struct captures IoTHub client configuration. */
typedef struct IOTHUB_CLIENT_CONFIG_TAG
{
    /** @brief A function pointer that is passed into the @c IoTHubClientCreate.
    *	A function definition for AMQP is defined in the include @c iothubtransportamqp.h.
    *   A function definition for HTTP is defined in the include @c iothubtransporthttp.h
    *   A function definition for MQTT is defined in the include @c iothubtransportmqtt.h */
    IOTHUB_CLIENT_TRANSPORT_PROVIDER protocol;

    /** @brief	A string that identifies the device. */
    const char* deviceId;
    
    /** @brief	The device key used to authenticate the device. */
    const char* deviceKey;

    /** @brief	The IoT Hub name to which the device is connecting. */
    const char* iotHubName;
    
    /** @brief	IoT Hub suffix goes here, e.g., private.azure-devices-int.net. */
    const char* iotHubSuffix;

    const char* protocolGatewayHostName;
} IOTHUB_CLIENT_CONFIG;

/** @brief	This struct captures IoTHub client device configuration. */
typedef struct IOTHUB_CLIENT_DEVICE_CONFIG_TAG
{
    /** @brief A function pointer that is passed into the @c IoTHubClientCreate.
    *	A function definition for AMQP is defined in the include @c iothubtransportamqp.h.
    *   A function definition for HTTP is defined in the include @c iothubtransporthttp.h
    *   A function definition for MQTT is defined in the include @c iothubtransportmqtt.h */
    IOTHUB_CLIENT_TRANSPORT_PROVIDER protocol;

    /** @brief a transport handle implementing the protocol */
    void * transportHandle;

    /** @brief	A string that identifies the device. */
    const char* deviceId;

    /** @brief	The device key used to authenticate the device. */
    const char* deviceKey;

} IOTHUB_CLIENT_DEVICE_CONFIG;

/** @brief	This struct captures IoTHub transport configuration. */
typedef struct IOTHUBTRANSPORT_CONFIG_TAG
{
	const IOTHUB_CLIENT_CONFIG* upperConfig;
	PDLIST_ENTRY waitingToSend;
}IOTHUBTRANSPORT_CONFIG;


/**
 * @brief	Creates a IoT Hub client for communication with an existing
 * 			IoT Hub using the specified connection string parameter.
 *
 * @param	connectionString	Pointer to a character string
 * @param	protocol			Function pointer for protocol implementation
 *
 *			Sample connection string:
 *				<blockquote>
 *					<pre>HostName=[IoT Hub name goes here].[IoT Hub suffix goes here, e.g., private.azure-devices-int.net];DeviceId=[Device ID goes here];SharedAccessKey=[Device key goes here];</pre>
 *				</blockquote>
 * 
 * @return	A non-NULL @c IOTHUB_CLIENT_LL_HANDLE value that is used when
 * 			invoking other functions for IoT Hub client and @c NULL on failure.
 */
extern IOTHUB_CLIENT_LL_HANDLE IoTHubClient_LL_CreateFromConnectionString(const char* connectionString, IOTHUB_CLIENT_TRANSPORT_PROVIDER protocol);

/**
 * @brief	Creates a IoT Hub client for communication with an existing IoT
 * 			Hub using the specified parameters.
 *
 * @param	config	Pointer to an @c IOTHUB_CLIENT_CONFIG structure
 *
 *			The API does not allow sharing of a connection across multiple
 *			devices. This is a blocking call.
 * 
 * @return	A non-NULL @c IOTHUB_CLIENT_LL_HANDLE value that is used when
 * 			invoking other functions for IoT Hub client and @c NULL on failure.
 */
extern IOTHUB_CLIENT_LL_HANDLE IoTHubClient_LL_Create(const IOTHUB_CLIENT_CONFIG* config);

/**
* @brief	Creates a IoT Hub client for communication with an existing IoT
* 			Hub using an existing transport.
*
* @param	config	Pointer to an @c IOTHUB_CLIENT_DEVICE_CONFIG structure
*
*			The API *allows* sharing of a connection across multiple
*			devices. This is a blocking call.
*
* @return	A non-NULL @c IOTHUB_CLIENT_LL_HANDLE value that is used when
* 			invoking other functions for IoT Hub client and @c NULL on failure.
*/
extern IOTHUB_CLIENT_LL_HANDLE IoTHubClient_LL_CreateWithTransport(const IOTHUB_CLIENT_DEVICE_CONFIG * config);

/**
 * @brief	Disposes of resources allocated by the IoT Hub client. This is a
 * 			blocking call.
 *
 * @param	iotHubClientHandle	The handle created by a call to the create function.
 */
extern void IoTHubClient_LL_Destroy(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle);

/**
 * @brief	Asynchronous call to send the message specified by @p eventMessageHandle. 
 *
 * @param	iotHubClientHandle		   	The handle created by a call to the create function.
 * @param	eventMessageHandle		   	The handle to an IoT Hub message.
 * @param	eventConfirmationCallback  	The callback specified by the device for receiving
 * 										confirmation of the delivery of the IoT Hub message.
 * 										This callback can be expected to invoke the
 * 										::IoTHubClient_LL_SendEventAsync function for the
 * 										same message in an attempt to retry sending a failing
 * 										message. The user can specify a @c NULL value here to
 * 										indicate that no callback is required.
 * @param	userContextCallback			User specified context that will be provided to the
 * 										callback. This can be @c NULL.
 *
 *			@b NOTE: The application behavior is undefined if the user calls
 *			the ::IoTHubClient_LL_Destroy function from within any callback.
 * 
 * @return	IOTHUB_CLIENT_OK upon success or an error code upon failure.
 */
extern IOTHUB_CLIENT_RESULT IoTHubClient_LL_SendEventAsync(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle, IOTHUB_MESSAGE_HANDLE eventMessageHandle, IOTHUB_CLIENT_EVENT_CONFIRMATION_CALLBACK eventConfirmationCallback, void* userContextCallback);

/**
 * @brief	This function returns the current sending status for IoTHubClient.
 *
 * @param	iotHubClientHandle		The handle created by a call to the create function.
 * @param	iotHubClientStatus		The sending state is populated at the address pointed
 * 									at by this parameter. The value will be set to
 * 									@c IOTHUBCLIENT_SENDSTATUS_IDLE if there is currently
 * 								    no item to be sent and @c IOTHUBCLIENT_SENDSTATUS_BUSY
 * 								    if there are.
 *
 * @return	IOTHUB_CLIENT_OK upon success or an error code upon failure.
 */
extern IOTHUB_CLIENT_RESULT IoTHubClient_LL_GetSendStatus(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle, IOTHUB_CLIENT_STATUS *iotHubClientStatus);

/**
 * @brief	Sets up the message callback to be invoked when IoT Hub issues a
 * 			message to the device. This is a blocking call.
 *
 * @param	iotHubClientHandle		   	The handle created by a call to the create function.
 * @param	messageCallback     	   	The callback specified by the device for receiving
 * 										messages from IoT Hub.
 * @param	userContextCallback			User specified context that will be provided to the
 * 										callback. This can be @c NULL.
 *
 *			@b NOTE: The application behavior is undefined if the user calls
 *			the ::IoTHubClient_LL_Destroy function from within any callback.
 * 
 * @return	IOTHUB_CLIENT_OK upon success or an error code upon failure.
 */
extern IOTHUB_CLIENT_RESULT IoTHubClient_LL_SetMessageCallback(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle, IOTHUB_CLIENT_MESSAGE_CALLBACK_ASYNC messageCallback, void* userContextCallback);

/**
 * @brief	This function returns in the out parameter @p lastMessageReceiveTime
 * 			what was the value of the @c time function when the last message was
 * 			received at the client.
 *
 * @param	iotHubClientHandle				The handle created by a call to the create function.
 * @param	lastMessageReceiveTime  		Out parameter containing the value of @c time function
 * 											when the last message was received.
 *
 * @return	IOTHUB_CLIENT_OK upon success or an error code upon failure.
 */
extern IOTHUB_CLIENT_RESULT IoTHubClient_LL_GetLastMessageReceiveTime(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle, time_t* lastMessageReceiveTime);

/**
 * @brief	This function is meant to be called by the user when work
 * 			(sending/receiving) can be done by the IoTHubClient.
 *
 * @param	iotHubClientHandle	The handle created by a call to the create function.
 *
 *			All IoTHubClient interactions (in regards to network traffic
 *			and/or user level callbacks) are the effect of calling this
 *			function and they take place synchronously inside _DoWork.
 */
extern void IoTHubClient_LL_DoWork(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle);

/**
 * @brief	This API sets a runtime option identified by parameter @p optionName
 * 			to a value pointed to by @p value. @p optionName and the data type
 * 			@p value is pointing to are specific for every option.
 *
 * @param	iotHubClientHandle	The handle created by a call to the create function.
 * @param	optionName		  	Name of the option.
 * @param	value			  	The value.
 *
 *			The options that can be set via this API are:
 *				- @b timeout - the maximum time in milliseconds a communication is  
 *				  allowed to use. @p value is a pointer to an @c unsigned @c int with
 *				  the timeout value in milliseconds. This is only supported for the HTTP
 *				  protocol as of now. When the HTTP protocol uses CURL, the meaning of
 *				  the parameter is <em>total request time</em>. When the HTTP protocol uses
 *				  winhttp, the meaning is the same as the @c dwSendTimeout and
 *				  @c dwReceiveTimeout parameters of the
 *				  <a href="https://msdn.microsoft.com/en-us/library/windows/desktop/aa384116(v=vs.85).aspx">
 *				  WinHttpSetTimeouts</a> API.
 *				- @b CURLOPT_LOW_SPEED_LIMIT - only available for HTTP protocol and only  
 *				  when CURL is used. It has the same meaning as CURL's option with the same
 *				  name. @p value is pointer to a long.
 *				- @b CURLOPT_LOW_SPEED_TIME - only available for HTTP protocol and only  
 *				  when CURL is used. It has the same meaning as CURL's option with the same
 *				  name. @p value is pointer to a long.
 *				- @b CURLOPT_FORBID_REUSE - only available for HTTP protocol and only  
 *				  when CURL is used. It has the same meaning as CURL's option with the same
 *				  name. @p value is pointer to a long.
 *				- @b CURLOPT_FRESH_CONNECT - only available for HTTP protocol and only  
 *				  when CURL is used. It has the same meaning as CURL's option with the same
 *				  name. @p value is pointer to a long.
 *				- @b CURLOPT_VERBOSE - only available for HTTP protocol and only  
 *				  when CURL is used. It has the same meaning as CURL's option with the same
 *				  name. @p value is pointer to a long.
 *              - @b keepalive - available for MQTT protocol.  Integer value that sets the 
 *                interval in seconds when pings are sent to the server.
 *              - @b logtrace - available for MQTT protocol.  Boolean value that turns on and
 *                off the diagnostic logging.
 *
 * @return	IOTHUB_CLIENT_OK upon success or an error code upon failure.
 */
extern IOTHUB_CLIENT_RESULT IoTHubClient_LL_SetOption(IOTHUB_CLIENT_LL_HANDLE iotHubClientHandle, const char* optionName, const void* value);

#ifdef __cplusplus
}
#endif

#endif /* IOTHUB_CLIENT_LL_H */