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blobmsg: introduce BLOBMSG_CAST_INT64

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When dealing with 64-bit integers in JSON documents, blobmsg_parse
becomes useless as blobmsg-json only uses BLOBMSG_TYPE_INT64 if the
value exceeds the range of a 32-bit integer, otherwise
BLOBMSG_TYPE_INT32 is used. This is because blobmsg-json parses the
JSON document ad-hoc without knowing the schema in advance and hence
a result of the design of blobmsg-json (and the absence of JSON
schema definitions).
In practise, this made code less readable as instead of using
blobmsg_parse() one had to to deal with *all* attributes manually just
to catch fields which can be both, BLOBMSG_TYPE_INT32 or
BLOBMSG_TYPE_INT64, but are always dealt with as uint64_t in code as
they potentially could exceed the 32-bit range.

To resolve this issue, introduce as special wildcard attribute
type BLOBMSG_CAST_INT64 which should only be used in policies used
by blobmsg_parse(). If used for an attribute in the policy,
blobmsg_parse shall accept all integer types and allow the user
to retrieve the value using the uint64_t blobmsg_cast_u64() and
int64_t blobmsg_cast_s64() functions which is also introduced by this
commit.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
This commit is contained in:
Daniel Golle 2020-08-04 01:27:09 +01:00
parent f4e9bf73ac
commit 9e52171d70
2 changed files with 41 additions and 0 deletions
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8
blobmsg.c
View file

@ -195,9 +195,17 @@ int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
continue;
if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
policy[i].type != BLOBMSG_CAST_INT64 &&
blob_id(attr) != policy[i].type)
continue;
if (policy[i].type == BLOBMSG_CAST_INT64 &&
(blob_id(attr) != BLOBMSG_TYPE_INT64 &&
blob_id(attr) != BLOBMSG_TYPE_INT32 &&
blob_id(attr) != BLOBMSG_TYPE_INT16 &&
blob_id(attr) != BLOBMSG_TYPE_INT8))
continue;
if (blobmsg_namelen(hdr) != pslen[i])
continue;

33
blobmsg.h
View file

@ -35,6 +35,7 @@ enum blobmsg_type {
__BLOBMSG_TYPE_LAST,
BLOBMSG_TYPE_LAST = __BLOBMSG_TYPE_LAST - 1,
BLOBMSG_TYPE_BOOL = BLOBMSG_TYPE_INT8,
BLOBMSG_CAST_INT64,
};
struct blobmsg_hdr {
@ -288,6 +289,38 @@ static inline uint64_t blobmsg_get_u64(struct blob_attr *attr)
return tmp;
}
static inline uint64_t blobmsg_cast_u64(struct blob_attr *attr)
{
uint64_t tmp = 0;
if (blobmsg_type(attr) == BLOBMSG_TYPE_INT64)
tmp = blobmsg_get_u64(attr);
else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT32)
tmp = blobmsg_get_u32(attr);
else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT16)
tmp = blobmsg_get_u16(attr);
else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT8)
tmp = blobmsg_get_u8(attr);
return tmp;
}
static inline int64_t blobmsg_cast_s64(struct blob_attr *attr)
{
int64_t tmp = 0;
if (blobmsg_type(attr) == BLOBMSG_TYPE_INT64)
tmp = blobmsg_get_u64(attr);
else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT32)
tmp = (int32_t)blobmsg_get_u32(attr);
else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT16)
tmp = (int16_t)blobmsg_get_u16(attr);
else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT8)
tmp = (int8_t)blobmsg_get_u8(attr);
return tmp;
}
static inline double blobmsg_get_double(struct blob_attr *attr)
{
union {