FreeRTOS-Kernel/Demo/Common/Utils/CommandInterpreter.c

/*
    FreeRTOS V7.0.2 - Copyright (C) 2011 Real Time Engineers Ltd.
	

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    This file is part of the FreeRTOS distribution.

    FreeRTOS is free software; you can redistribute it and/or modify it under
    the terms of the GNU General Public License (version 2) as published by the
    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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*/

/* Standard includes. */
#include <string.h>

/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"

/* Utils includes. */
#include "CommandInterpreter.h"

typedef struct xCOMMAND_INPUT_LIST
{
	const xCommandLineInput *pxCommandLineDefinition;
	struct xCOMMAND_INPUT_LIST *pxNext;
} xCommandLineInputListItem;

/*
 * The callback function that is executed when "help" is entered.  This is the
 * only default command that is always present.
 */
static portBASE_TYPE prvHelpCommand( signed char *pcWriteBuffer, size_t xWriteBufferLen );

/* The definition of the "help" command.  This command is always at the front
of the list of registered commands. */
static const xCommandLineInput xHelpCommand = 
{
	( const signed char * const ) "help",
	( const signed char * const ) "help: Lists all the registered commands\r\n",
	prvHelpCommand
};

/* The definition of the list of commands.  Commands that are registered are
added to this list. */
static xCommandLineInputListItem xRegisteredCommands =
{	
	&xHelpCommand,	/* The first command in the list is always the help command, defined in this file. */
	NULL			/* The next pointer is initialised to NULL, as there are no other registered commands yet. */
};

/* A buffer into which command outputs can be written is declared here, rather
than in the command console implementation, to allow multiple command consoles
to share the same buffer.  For example, an application may allow access to the
command interpreter by UART and by Ethernet.  Sharing a buffer is done purely
to save RAM.  Note, however, that the command console itself is not re-entrant,
so only one command interpreter interface can be used at any one time.  For that
reason, no attempt at providing mutual exclusion to the cOutputBuffer array is
attempted. */
static signed char cOutputBuffer[ configCOMMAND_INT_MAX_OUTPUT_SIZE ];

/*-----------------------------------------------------------*/

portBASE_TYPE xCmdIntRegisterCommand( const xCommandLineInput * const pxCommandToRegister )
{
static xCommandLineInputListItem *pxLastCommandInList = &xRegisteredCommands;
xCommandLineInputListItem *pxNewListItem;
portBASE_TYPE xReturn = pdFAIL;

	/* Check the parameter is not NULL. */
	configASSERT( pxCommandToRegister );

	/* Create a new list item that will reference the command being registered. */
	pxNewListItem = ( xCommandLineInputListItem * ) pvPortMalloc( sizeof( xCommandLineInputListItem ) );
	configASSERT( pxNewListItem );

	if( pxNewListItem != NULL )
	{
		taskENTER_CRITICAL();
		{
			/* Reference the command being registered from the newly created 
			list item. */
			pxNewListItem->pxCommandLineDefinition = pxCommandToRegister;

			/* The new list item will get added to the end of the list, so 
			pxNext has nowhere to point. */
			pxNewListItem->pxNext = NULL;

			/* Add the newly created list item to the end of the already existing
			list. */
			pxLastCommandInList->pxNext = pxNewListItem;

			/* Set the end of list marker to the new list item. */
			pxLastCommandInList = pxNewListItem;
		}
		taskEXIT_CRITICAL();
		
		xReturn = pdPASS;
	}

	return xReturn;
}
/*-----------------------------------------------------------*/

portBASE_TYPE xCmdIntProcessCommand( const signed char * const pcCommandInput, signed char * pcWriteBuffer, size_t xWriteBufferLen  )
{
static const xCommandLineInputListItem *pxCommand = NULL;
portBASE_TYPE xReturn;

	/* Note:  This function is not re-entrant.  It must not be called from more
	thank one task. */

	if( pxCommand == NULL )
	{
		/* Search for the command string in the list of registered commands. */
		for( pxCommand = &xRegisteredCommands; pxCommand != NULL; pxCommand = pxCommand->pxNext )
		{
			if( strcmp( ( const char * ) pcCommandInput, ( const char * ) pxCommand->pxCommandLineDefinition->pcCommand ) == 0 )
			{
				/* The command has been found, the loop can exit so the command
				can be executed. */
				break;
			}
		}
	}

	if( pxCommand != NULL )
	{
		/* Call the callback function that is registered to this command. */
		xReturn = pxCommand->pxCommandLineDefinition->pxCommandInterpreter( pcWriteBuffer, xWriteBufferLen );

		/* If xReturn is pdFALSE, then no further strings will be returned
		after this one, and	pxCommand can be reset to NULL ready to search 
		for the next entered command. */
		if( xReturn == pdFALSE )
		{
			pxCommand = NULL;
		}
	}
	else
	{
		strncpy( ( char * ) pcWriteBuffer, ( const char * const ) "Command not recognised.  Enter \"help\" to view a list of available commands.\r\n\r\n", xWriteBufferLen );
		xReturn = pdFALSE;
	}

	return xReturn;
}
/*-----------------------------------------------------------*/

signed char *pcCmdIntGetOutputBuffer( void )
{
	return cOutputBuffer;
}
/*-----------------------------------------------------------*/

unsigned portBASE_TYPE uxCmdIntGetOutputBufferSizeBytes( void )
{
	return configCOMMAND_INT_MAX_OUTPUT_SIZE;
}
/*-----------------------------------------------------------*/

static portBASE_TYPE prvHelpCommand( signed char *pcWriteBuffer, size_t xWriteBufferLen )
{
static const xCommandLineInputListItem * pxCommand = NULL;
signed portBASE_TYPE xReturn;

	if( pxCommand == NULL )
	{
		/* Reset the pxCommand pointer back to the start of the list. */
		pxCommand = &xRegisteredCommands;
	}

	/* Return the next command help string, before moving the pointer on to
	the next command in the list. */
	strncpy( ( char * ) pcWriteBuffer, ( const char * ) pxCommand->pxCommandLineDefinition->pcHelpString, xWriteBufferLen );
	pxCommand = pxCommand->pxNext;

	if( pxCommand == NULL )
	{
		/* There are no more commands in the list, so there will be no more
		strings to return after this one and pdFALSE should be returned. */
		xReturn = pdFALSE;
	}
	else
	{
		xReturn = pdTRUE;
	}

	return xReturn;
}