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*
* \defgroup parser Simple RPC machinery
* \ingroup mware
* \{
*
* \brief Channel protocol parser and commands.
*
* This module provides a simple text based RPC implementation.
* Often there is the need to give a command to the device and receive results
* back. Each command may have a variable number of input and output
* parameters, with variable type, and a return code which indicates if the
* command was successfully executed or not; this module provides the machinery
* to facilitate the above RPC scenario.
* You will need to write the RPC input and reply code as well as
* the definition of the commands.
*
* Commands are defined using a CmdTemplate struct containing:
* - command name: the string that will be matched by the parser;
* - command arguments: a string representing type and number of input
* arguments;
* - command output: a string representing type and number of output arguments;
* - function callback: function implementing the command.
*
* Once you have declared the commands, you need to register them in the
* parser with the function parser_register_cmd().
* You are strongly encouraged to use MAKE_CMD() (or alternatively
* MAKE_TEMPLATE()) and REGISTER_CMD() to declare and register commands.
*
* A command line can be parsed with the following steps:
* - find the corresponding command template with parser_get_cmd_template()
* - extract command arguments with parser_get_cmd_arguments()
* - execute the command with parser_execute_cmd()
*
* You can also provide interactive command line completion using
* parser_rl_match().
*
* Example:
* \code
* // Declare a buzzer command
* MAKE_CMD(beep, "d", "",
* ({
* buz_beep(args[1].l);
* RC_OK;
* }), 0)
*
* // initialize the parser
* parser_init();
* REGISTER_CMD(beep);
*
* // parse an input line
* char buf[80];
* // read line from somewhere
* rpc_get(buf);
* // now parse the line
* const struct CmdTemplate *templ;
* templ = parser_get_cmd_template(buf);
*
* // Take arguments (optionally check errors)
* parms args[PARSER_MAX_ARGS];
* parser_get_cmd_arguments(buf, templ, args);
* //Execute command
* if(!parser_execute_cmd(templ, args))
* {
* // error
* }
* // Now args contain the outputs of the function, you can send it
* // back to the caller
* rpc_reply(args)
*
* \endcode
*
* <b>Configuration file</b>: cfg_parser.h
*
* \author Bernie Innocenti <bernie@codewiz.org>
* \author Stefano Fedrigo <aleph@develer.com>
* \author Giovanni Bajo <rasky@develer.com>
*
* $WIZ$ module_name = "parser"
* $WIZ$ module_configuration = "bertos/cfg/cfg_parser.h"
* $WIZ$ module_depends = "kfile", "hashtable"
*/
#ifndef MWARE_PARSER_H
#define MWARE_PARSER_H
#include "cfg/cfg_parser.h"
#include <cpu/types.h>
#include <cfg/debug.h>
/**
* Error generated by the commands through the return code.
*/
typedef enum
{
RC_ERROR = -1, ///< Reply with error.
RC_OK = 0, ///< No reply (ignore reply arguments).
RC_REPLY = 1, ///< Reply command arguments.
RC_SKIP = 2 ///< Skip following commands
} ResultCode;
/** union that contains parameters passed to and from commands */
typedef union { long l; const char *s; } parms;
/** pointer to commands */
typedef ResultCode (*CmdFuncPtr)(parms args_results[]);
/**
* Define a command that can be tokenized by the parser.
*
* The format strings are sequences of characters, one for each
* parameter/result. Valid characters are:
*
* d - a long integer, in decimal format
* s - a var string (in RAM)
*
* \note To create and fill an instance for this function, it is strongly
* advised to use \c DECLARE_CMD_HUNK (cmd_hunk.h).
*/
struct CmdTemplate
{
const char *name; ///< Name of command
const char *arg_fmt; ///< Format string for the input
const char *result_fmt; ///< Format string for the output
CmdFuncPtr func; ///< Pointer to the handler function
uint16_t flags; ///< Currently unused.
};
#define REGISTER_FUNCTION parser_register_cmd
/**
* Utility function to register a command.
*
* \param NAME Command name to register
*/
#define REGISTER_CMD(NAME) \
do { \
if (!REGISTER_FUNCTION(&cmd_ ## NAME ## _template)) \
ASSERT2(0, "Error in registering command, no space left"); \
} while (0)
/**
* Utility macro to create a command template.
*
* It requires that a callback function with name \a cmd_NAME
* is already defined.
* \param NAME Command name
* \param ARGS Input arguments
* \param RES Output arguments
* \param FLAGS Command flags
*/
#define MAKE_TEMPLATE(NAME, ARGS, RES, FLAGS) \
const struct CmdTemplate cmd_ ## NAME ## _template = \
{ \
#NAME, ARGS, RES, cmd_ ## NAME, FLAGS \
};
/**
* Utility macro to create command templates and callback functions.
*
* Example for a version command:
* \code
* MAKE_CMD(ver, "", "ddd",
* ({
* args[1].l = VERS_MAJOR;
* args[2].l = VERS_MINOR;
* args[3].l = VERS_REV;
* RC_OK;
* }), 0);
* \endcode
*
* Remember that input and output parameters start from index 1, since
* args[0] is the command itself.
* The last line is the return value of the function.
*
* \param NAME Command name matched by the parser
* \param ARGS Input arguments to the command
* \param RES Output arguments of the command
* \param BODY Command body, expressed with C 'statement expression'
* \param FLAGS Command flags
*/
#define MAKE_CMD(NAME, ARGS, RES, BODY, FLAGS) \
static ResultCode cmd_ ## NAME (parms *args) \
{ \
return (ResultCode)BODY; \
} \
MAKE_TEMPLATE(NAME, ARGS, RES, FLAGS)
/**
* Initialize the parser module
*
* \note This function must be called before any other function in this module
*/
void parser_init(void);
bool parser_register_cmd(const struct CmdTemplate* cmd);
/**
* Hook for readline to provide completion support for the commands
* registered in the parser.
*
* \note This is meant to be used with mware/readline.c. See the
* documentation there for a description of this hook.
*/
const char* parser_rl_match(void* dummy, const char* word, int word_len);
bool parser_process_line(const char* line);
/**
* Execute a command with its arguments, and fetch its results.
*
* The \a args paramenter is value-result: it provides input arguments to
* the callback function and it stores output values on return.
*
* \param templ Template of the command to be executed
* \param args Arguments for the command, and will contain the results
*
* \return False if the command returned an error, true otherwise
*/
INLINE bool parser_execute_cmd(const struct CmdTemplate* templ, parms args[CONFIG_PARSER_MAX_ARGS])
{
return (templ->func(args) == 0);
}
const struct CmdTemplate* parser_get_cmd_template(const char* line);
bool parser_get_cmd_arguments(const char* line, const struct CmdTemplate* templ, parms args[CONFIG_PARSER_MAX_ARGS]);
#if CONFIG_ENABLE_COMPAT_BEHAVIOUR
/**
* Extract the ID from the command text line.
*
* \param line Text line to be processed (ASCIIZ)
* \param ID Will contain the ID extracted.
*
* \return True if everything ok, false if there is no ID
*
*/
bool parser_get_cmd_id(const char* line, unsigned long* ID);
#endif
/** \} */ // defgroup parser
#endif /* MWARE_PARSER_H */