use std::fmt;
use serde::{de::DeserializeOwned, Serialize};
use serde_json::value::RawValue as RawJsonValue;
use crate::serde::{CanBeEmpty, Raw};
use super::{
EphemeralRoomEventType, GlobalAccountDataEventType, MessageLikeEventType,
RoomAccountDataEventType, StateEventType, StateUnsignedFromParts, ToDeviceEventType,
};
/// The base trait that all event content types implement.
///
/// Use [`macros::EventContent`] to derive this traits. It is not meant to be implemented manually.
///
/// [`macros::EventContent`]: super::macros::EventContent
pub trait EventContent: Sized + Serialize {
/// The Rust enum for the event kind's known types.
type EventType;
/// Get the event's type, like `m.room.message`.
fn event_type(&self) -> Self::EventType;
/// Constructs the given event content.
#[doc(hidden)]
fn from_parts(event_type: &str, content: &RawJsonValue) -> serde_json::Result<Self>;
}
impl<T> Raw<T>
where
T: EventContent,
T::EventType: fmt::Display,
{
/// Try to deserialize the JSON as an event's content.
pub fn deserialize_content(&self, event_type: T::EventType) -> serde_json::Result<T> {
T::from_parts(&event_type.to_string(), self.json())
}
}
/// The base trait that all redacted event content types implement.
///
/// This trait's associated functions and methods should not be used to build
/// redacted events, prefer the `redact` method on `AnyStateEvent` and
/// `AnyMessageLikeEvent` and their "sync" and "stripped" counterparts.
/// The `RedactedEventContent` trait is an implementation detail, ruma makes no
/// API guarantees.
pub trait RedactedEventContent: EventContent {
/// Constructs the redacted event content.
///
/// If called for anything but "empty" redacted content this will error.
#[doc(hidden)]
fn empty(_event_type: &str) -> serde_json::Result<Self> {
Err(serde::de::Error::custom("this event is not redacted"))
}
/// Determines if the redacted event content needs to serialize fields.
#[doc(hidden)]
fn has_serialize_fields(&self) -> bool;
/// Determines if the redacted event content needs to deserialize fields.
#[doc(hidden)]
fn has_deserialize_fields() -> HasDeserializeFields;
}
/// `HasDeserializeFields` is used in the code generated by the `Event` derive
/// to aid in deserializing redacted events.
#[doc(hidden)]
#[derive(Debug)]
#[allow(clippy::exhaustive_enums)]
pub enum HasDeserializeFields {
/// Deserialize the event's content, failing if invalid.
True,
/// Return the redacted version of this event's content.
False,
/// `Optional` is used for `RedactedAliasesEventContent` since it has
/// an empty version and one with content left after redaction that
/// must be supported together.
Optional,
}
/// Trait for abstracting over event content structs.
///
/// … but *not* enums which don't always have an event type and kind (e.g. message vs state) that's
/// fixed / known at compile time.
pub trait StaticEventContent: EventContent {
/// The event's "kind".
///
/// See the type's documentation.
const KIND: EventKind;
/// The event type.
const TYPE: &'static str;
}
/// The "kind" of an event.
///
/// This corresponds directly to the event content marker traits.
#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[non_exhaustive]
pub enum EventKind {
/// Global account data event kind.
GlobalAccountData,
/// Room account data event kind.
RoomAccountData,
/// Ephemeral room event kind.
EphemeralRoomData,
/// Message-like event kind.
///
/// Since redacted / non-redacted message-like events are used in the same places but have
/// different sets of fields, these two variations are treated as two closely-related event
/// kinds.
MessageLike {
/// Redacted variation?
redacted: bool,
},
/// State event kind.
///
/// Since redacted / non-redacted state events are used in the same places but have different
/// sets of fields, these two variations are treated as two closely-related event kinds.
State {
/// Redacted variation?
redacted: bool,
},
/// To-device event kind.
ToDevice,
/// Presence event kind.
Presence,
}
/// Content of a global account-data event.
pub trait GlobalAccountDataEventContent:
EventContent<EventType = GlobalAccountDataEventType>
{
}
/// Content of a room-specific account-data event.
pub trait RoomAccountDataEventContent: EventContent<EventType = RoomAccountDataEventType> {}
/// Content of an ephemeral room event.
pub trait EphemeralRoomEventContent: EventContent<EventType = EphemeralRoomEventType> {}
/// Content of a non-redacted message-like event.
pub trait MessageLikeEventContent: EventContent<EventType = MessageLikeEventType> {}
/// Content of a redacted message-like event.
pub trait RedactedMessageLikeEventContent: MessageLikeEventContent + RedactedEventContent {}
/// Content of a redacted state event.
pub trait StateEventContent: EventContent<EventType = StateEventType> {
/// The type of the event's `state_key` field.
type StateKey: AsRef<str> + Clone + fmt::Debug + DeserializeOwned + Serialize;
/// The type of the event's `unsigned` field.
type Unsigned: Clone + fmt::Debug + Default + CanBeEmpty + StateUnsignedFromParts + Serialize;
}
/// Content of a non-redacted state event.
pub trait RedactedStateEventContent: StateEventContent + RedactedEventContent {}
/// Content of a to-device event.
pub trait ToDeviceEventContent: EventContent<EventType = ToDeviceEventType> {}