114 lines
3.5 KiB
C
114 lines
3.5 KiB
C
#ifndef LIGHTNING_LIGHTNINGD_PARAM_H
|
|
#define LIGHTNING_LIGHTNINGD_PARAM_H
|
|
#include "config.h"
|
|
|
|
/*
|
|
Typesafe callback system for unmarshalling and validating json parameters.
|
|
|
|
Typical usage:
|
|
unsigned cltv;
|
|
u64 *msatoshi;
|
|
const jsmntok_t *note;
|
|
u64 expiry;
|
|
|
|
if (!param(cmd, buffer, params,
|
|
p_req("cltv", json_tok_number, &cltv),
|
|
p_opt("msatoshi", json_tok_u64, &msatoshi),
|
|
p_opt_tok("note", ¬e),
|
|
p_opt_def("expiry", json_tok_u64, &expiry, 3600),
|
|
NULL))
|
|
return;
|
|
|
|
At this point in the code you can be assured the json tokens were successfully
|
|
parsed. If not, param() returned false, having already called command_fail()
|
|
with a descriptive error message. The data section of the json result contains
|
|
the offending parameter and its value.
|
|
|
|
cltv is a required parameter. It must be present in the json input and will
|
|
be set appropriately.
|
|
|
|
msatoshi is optional. If not present it will be set to NULL.
|
|
|
|
note is also optional. It uses a special callback that simply sets note to the
|
|
appropriate value (or NULL) and lets the handler do the validating.
|
|
|
|
expiry is also optional and will be set to a default value if not present.
|
|
|
|
There are canned failure messages for common callbacks. An example:
|
|
|
|
'msatoshi' should be an unsigned 64 bit integer, not '123z'
|
|
|
|
Otherwise a generic message is provided.
|
|
*/
|
|
|
|
/*
|
|
* parse the json tokens. @params can be an array of values, or an object
|
|
* of named values.
|
|
*/
|
|
bool param(struct command *cmd, const char *buffer,
|
|
const jsmntok_t params[], ...);
|
|
|
|
/*
|
|
* The callback provided must follow this signature; e.g.,
|
|
* bool json_tok_double(const char *buffer, const jsmntok_t *tok, double *arg)
|
|
*/
|
|
typedef bool(*param_cb)(const char *buffer, const jsmntok_t *tok, void *arg);
|
|
|
|
/*
|
|
* Add a handler to unmarshal a required json token into @arg. The handler must
|
|
* return true on success and false on failure. Upon failure, command_fail will be
|
|
* called with a descriptive error message.
|
|
*
|
|
* This operation is typesafe; i.e., a compilation error will occur if the types
|
|
* of @arg and the last parameter of @cb do not match (see the weird 0*sizeof).
|
|
*/
|
|
#define p_req(name, cb, arg) \
|
|
name"", \
|
|
true, \
|
|
(cb), \
|
|
(arg) + 0*sizeof((cb)((const char *)NULL, \
|
|
(const jsmntok_t *)NULL, \
|
|
(arg)) == true), \
|
|
(size_t)0
|
|
|
|
/*
|
|
* Similar to above but for optional parameters.
|
|
* @arg must be the address of a pointer. If found during parsing, it will be
|
|
* allocated, otherwise it will be set to NULL.
|
|
*/
|
|
#define p_opt(name, cb, arg) \
|
|
name"", \
|
|
false, \
|
|
(cb), \
|
|
(arg) + 0*sizeof((cb)((const char *)NULL, \
|
|
(const jsmntok_t *)NULL, \
|
|
*(arg)) == true), \
|
|
sizeof(**(arg))
|
|
|
|
/*
|
|
* Similar to p_req but for optional parameters with defaults.
|
|
* @arg will be set to @def if it isn't found during parsing.
|
|
*/
|
|
#define p_opt_def(name, cb, arg, def) \
|
|
name"", \
|
|
false, \
|
|
(cb), \
|
|
(arg) + 0*sizeof((cb)((const char *)NULL, \
|
|
(const jsmntok_t *)NULL, \
|
|
(arg)) == true), \
|
|
((void)((*arg) = (def)), (size_t)0)
|
|
|
|
/*
|
|
* For when you want an optional raw token.
|
|
*
|
|
* Note: weird sizeof() does type check that arg really is a (const) jsmntok_t **.
|
|
*/
|
|
#define p_opt_tok(name, arg) \
|
|
name"", \
|
|
false, \
|
|
json_tok_tok, \
|
|
(arg) + 0*sizeof(*(arg) == (jsmntok_t *)NULL), \
|
|
sizeof(const jsmntok_t *)
|
|
|
|
#endif /* LIGHTNING_LIGHTNINGD_PARAM_H */
|