Module postcard::experimental
source · Expand description
§Experimental Postcard Features
Items inside this module require various feature flags, and are not subject to SemVer stability. Items may be removed or deprecated at any point.
§Derive
The experimental-derive
feature enables two experimental features:
- Max size calculation
- Message schema generation
§Max Size Calculation
This features enables calculation of the Max serialized size of a message as
an associated usize
constant called POSTCARD_MAX_SIZE
. It also provides a
#[derive(MaxSize)]
macro that can be used for calculating user types.
This is useful for determining the maximum buffer size needed when recieving or sending a message that has been serialized.
NOTE: This only covers the size of “plain” flavored messages, e.g. not with COBS or any other Flavors applied. The overhead for these flavors must be calculated separately.
Please report any missing types, or any incorrectly calculated values.
§Message Schema Generation
This feature enables the generation of a schema of a given message at compile
time. At the moment, this is only exposed as a NamedType
which is a recursive data structure describing the schema. In the future, it is planned
to provide formatting functions that emit this as a human or machine readable schema.
NOTE: This only covers the schema of “plain” flavored messages, e.g. not with COBS or any other Flavors applied. The format of these flavors must be calculated separately.
Please report any missing types, or any incorrectly calculated schemas.
Functions§
- Compute the size of the postcard serialization of
T
.