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| -rw-r--r-- | src/helper/command.h | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/src/helper/command.h b/src/helper/command.h index ded76fee..236dabbe 100644 --- a/src/helper/command.h +++ b/src/helper/command.h @@ -80,6 +80,48 @@ typedef struct command_context_s void *output_handler_priv; } command_context_t; + +/** + * Command handlers may be defined with more parameters than the base + * set provided by command.c. This macro uses C99 magic to allow + * defining all such derivative types using this macro. + */ +#define __COMMAND_HANDLER(name, extra...) \ + int name(struct command_context_s *cmd_ctx, \ + char *cmd, char **args, int argc, ##extra) + +/** + * Use this to macro to call a command helper (or a nested handler). + * It provides command handler authors protection against reordering or + * removal of unused parameters. + * + * @b Note: This macro uses lexical capture to provide some arguments. + * As a result, this macro should be used @b only within functions + * defined by the COMMAND_HANDLER or COMMAND_HELPER macros. Those + * macros provide the expected lexical context captured by this macro. + * Furthermore, it should be used only from the top-level of handler or + * helper function, or care must be taken to avoid redefining the same + * variables in intervening scope(s) by accident. + */ +#define CALL_COMMAND_HANDLER(name, extra...) \ + name(cmd_ctx, cmd, args, argc, ##extra) + +/** + * Always use this macro to define new command handler functions. + * It ensures the parameters are ordered, typed, and named properly, so + * they be can be used by other macros (e.g. COMMAND_PARSE_NUMBER). + * All command handler functions must be defined as static in scope. + */ +#define COMMAND_HANDLER(name) static __COMMAND_HANDLER(name) + +/** + * Similar to COMMAND_HANDLER, except some parameters are expected. + * A helper is globally-scoped because it may be shared between several + * source files (e.g. the s3c24xx device command helper). + */ +#define COMMAND_HELPER(name, extra...) __COMMAND_HANDLER(name, extra) + + typedef struct command_s { char *name; |