//! The atproto data model, its canonical encoding, and the CIDs that names.
//!
//! atproto's records are exchanged as JSON and *identified* as DAG-CBOR. The
//! two are the same data model wearing different clothes, and the identity of
//! a record — the CID a commit signs, a link quotes and an MST keys on — is
//! the sha-256 of the DAG-CBOR bytes. Everything downstream of that hash
//! depends on there being exactly one such encoding per record, which is why
//! this crate is three narrow pieces rather than a serializer:
//!
//! * [`Value`] is the data model: the values that *have* an encoding, and
//!   nothing else. Building one from JSON is where every rejection happens.
//! * [`dag_cbor`] turns one into bytes, and cannot fail. It reads them back
//!   too, which is a stricter job: see [`dag_cbor::decode`].
//! * [`Cid`] is the hash of those bytes, and the only string form atproto
//!   permits for it.
//!
//! * [`mst`] is the fourth piece and the largest: the Merkle search tree a
//!   repository is keyed by, along with the two pure functions its shape
//!   comes from.
//!
//! ```
//! use didbot_data::{dag_cbor, Value};
//!
//! let record = serde_json::json!({
//!     "$type": "com.example.thing",
//!     "text": "quernstone",
//!     "count": 1,
//! });
//! let value = Value::object_from_json(&record).expect("a data-model record");
//! let bytes = dag_cbor::encode(&value);
//! assert_eq!(dag_cbor::cid(&value), didbot_data::Cid::of_dag_cbor(&bytes));
//! ```
//!
//! # Why this is its own crate
//!
//! It sits below everything that would use it and depends on none of them. A
//! repository needs it to name a record, a Merkle search tree needs it to key
//! one, a commit needs it to sign one, and a CAR file needs it to frame one.
//! The tree is here, because a tree is nothing but keys and the encoding of
//! its own nodes; the commit and the CAR are in `didbot-repo`, because
//! they need a signing key and this crate deliberately depends on nothing.
//!
//! # What this crate does not do
//!
//! It is not a `serde` data format: records arrive here as `serde_json::Value` from
//! an HTTP body, and a derive-driven path would only add a second way to
//! produce bytes that must be identical to these.
//!
//! The conformance suite this is held to is `data-model/` in the vendored
//! upstream vectors; see `docs/conformance.md`.

#![forbid(unsafe_code)]

pub mod cid;
pub mod dag_cbor;
mod encoding;
pub mod mst;
pub mod value;

pub use cid::{Cid, CidError, RawHasher};
pub use value::{DataError, ErrorKind, Value};