tuwunel_core/matrix/

pdu.rs

//! Persistent data unit storage and federation-format utilities.
//!
//! The module contains the stored event representation, sequence identifiers,
//! builders, and validation helpers. Its wire-format adapters account for
//! room-version rules.

mod builder;
mod count;
mod format;
mod hashes;
mod id;
mod raw_id;
#[cfg(test)]
mod tests;
mod unsigned;

use std::cmp::Ordering;

use ruma::{
	CanonicalJsonObject, CanonicalJsonValue, EventId, MilliSecondsSinceUnixEpoch, OwnedEventId,
	OwnedRoomId, OwnedServerName, OwnedUserId, RoomId, UInt, UserId,
	canonical_json::redact_in_place,
	events::TimelineEventType,
	room_version_rules::{RedactionRules, RoomVersionRules},
	serde::Raw,
};
use serde::{Deserialize, Serialize};
use serde_json::value::RawValue as RawJsonValue;
use smallvec::SmallVec;

pub use self::{
	Count as PduCount, Id as PduId, Pdu as PduEvent, RawId as RawPduId,
	builder::{Builder, Builder as PduBuilder},
	count::Count,
	format::{
		check::{check_room_id, check_rules},
		from_incoming_federation, into_outgoing_federation,
	},
	hashes::EventHashes as EventHash,
	id::Id,
	raw_id::*,
};
use super::{Event, ShortRoomId, StateKey};
use crate::{Result, err};

/// Stores a Matrix persistent data unit in typed form.
///
/// The representation retains canonical event fields used by state resolution,
/// storage, and client serialization. Federation adapters normalize
/// version-specific wire shapes.
#[derive(Clone, Deserialize, Serialize, Debug)]
pub struct Pdu {
	/// Matrix event type.
	///
	/// The value is serialized under the top-level `type` field.
	#[serde(rename = "type")]
	pub kind: TimelineEventType,

	/// Raw canonical event content.
	///
	/// Content remains encoded until a caller requests a typed or JSON value.
	pub content: Content,

	/// Matrix identifier assigned to this event.
	///
	/// Stored PDUs always carry an owned event ID, including room versions that
	/// derive it outside the federation wire object.
	pub event_id: OwnedEventId,

	/// Matrix room containing this event.
	///
	/// Stored PDUs carry the room ID even when a room version omits it from a
	/// creation event's federation representation.
	pub room_id: OwnedRoomId,

	/// Matrix user who sent the event.
	///
	/// The sender participates in authorization and client-visible event
	/// output.
	pub sender: OwnedUserId,

	/// State key when this is a state event.
	///
	/// Message-like events store `None` and omit the field during
	/// serialization.
	#[serde(skip_serializing_if = "Option::is_none")]
	pub state_key: Option<StateKey>,

	/// Event targeted by a redaction when carried at the top level.
	///
	/// Newer room versions can place this value in event content instead. An
	/// absent target is omitted during serialization.
	#[serde(skip_serializing_if = "Option::is_none")]
	pub redacts: Option<OwnedEventId>,

	/// Events declared as direct predecessors of this event.
	///
	/// The sequence is stored inline for the common single-predecessor case.
	pub prev_events: PrevEvents,

	/// Events used to authorize this event.
	///
	/// These identifiers form the event's explicit authorization dependency
	/// set.
	pub auth_events: AuthEvents,

	/// Millisecond timestamp supplied by the originating server.
	///
	/// The value is preserved for ordering metadata and client serialization.
	pub origin_server_ts: UInt,

	/// Event depth in the room directed acyclic graph.
	///
	/// Depth is originating-server-provided graph metadata and is distinct from
	/// the local timeline sequence.
	pub depth: UInt,

	/// Content hash declared by the event.
	///
	/// Federation validation compares the declaration with the computed content
	/// hash to detect content changes.
	pub hashes: EventHash,

	/// Server that originated an event carrying a top-level `origin` field.
	///
	/// Legacy event formats retain this value for local and remote events. The
	/// field is absent when it was not carried by the event format.
	#[serde(skip_serializing_if = "Option::is_none")]
	pub origin: Option<OwnedServerName>,

	/// Unsigned metadata excluded from event hashing and signing.
	///
	/// Stored values are local annotations such as transaction IDs, age, prior
	/// state, and bundled relations. The field is omitted when absent.
	#[serde(default, skip_serializing_if = "Option::is_none")]
	pub unsigned: Option<Unsigned>,

	//TODO: https://spec.matrix.org/v1.14/rooms/v11/#rejected-events
	/// Whether state resolution rejected this event in test fixtures.
	///
	/// Production builds derive rejection state outside the serialized PDU.
	#[cfg(test)]
	#[serde(default, skip_serializing)]
	pub rejected: bool,
}

/// Inline storage for the common single-entry `prev_events` case.
///
/// Events with additional predecessors spill to the heap, avoiding larger
/// inline storage on every event.
pub type PrevEvents = SmallVec<[OwnedEventId; 1]>;

/// Inline storage for the typical three-entry `auth_events` case.
///
/// Restricted rooms can require many more entries, so this remains a spilling
/// `SmallVec` rather than a fixed-capacity `ArrayVec`.
pub type AuthEvents = SmallVec<[OwnedEventId; 3]>;

/// Raw event-content storage with 112 bytes of inline capacity.
///
/// The capacity follows an allocator-profile mode in the 96 to 112 byte range
/// and targets a 128 byte total size with `SmallVec` metadata.
pub type Content = Raw<CanonicalJsonObject, 112>;

/// Raw `unsigned` storage with 112 bytes of inline capacity.
///
/// The enclosing field is usually `None` or contains a small local annotation,
/// such as `transaction_id`, `age`, or `membership`. Those values remain inline
/// at the `Content` size class, while larger state-event `prev_content` and
/// bundled `m.relations` values spill to the heap.
pub type Unsigned = Raw<CanonicalJsonObject, 112>;

/// The [maximum size allowed] for a PDU.
/// [maximum size allowed]: <https://spec.matrix.org/latest/client-server-api/#size-limits>
pub const MAX_PDU_BYTES: usize = 65_535;

/// The [maximum length allowed] for the `prev_events` array of a PDU.
/// [maximum length allowed]: <https://spec.matrix.org/latest/rooms/v1/#event-format>
pub const MAX_PREV_EVENTS: usize = 20;

/// The [maximum length allowed] for the `auth_events` array of a PDU.
/// [maximum length allowed]: <https://spec.matrix.org/latest/rooms/v1/#event-format>
pub const MAX_AUTH_EVENTS: usize = 10;

impl Pdu {
	/// Inserts room and event IDs before deserializing a canonical PDU object.
	///
	/// Existing values under those keys are replaced. The resulting typed PDU
	/// owns both supplied identifiers.
	pub fn from_object_and_roomid_and_eventid(
		room_id: &RoomId,
		event_id: &EventId,
		mut json: CanonicalJsonObject,
	) -> Result<Self> {
		let room_id = CanonicalJsonValue::String(room_id.into());
		json.insert("room_id".into(), room_id);
		Self::from_object_and_eventid(event_id, json)
	}

	/// Inserts an event ID before deserializing a canonical PDU object.
	///
	/// Any existing `event_id` value is replaced. Other object fields pass
	/// through to normal PDU deserialization.
	pub fn from_object_and_eventid(
		event_id: &EventId,
		mut json: CanonicalJsonObject,
	) -> Result<Self> {
		let event_id = CanonicalJsonValue::String(event_id.into());
		json.insert("event_id".into(), event_id);
		Self::from_object(json)
	}

	/// Normalizes federation wire fields and validates PDU format and room ID.
	///
	/// Version-specific wire fields are converted to the stored representation
	/// before these checks. Signature, content-hash, and authorization
	/// validation remain the caller's responsibility.
	///
	/// # Panics
	///
	/// Panics if the object lacks `type` while the selected rules do not
	/// require a create-event room ID.
	pub fn from_object_federation(
		room_id: &RoomId,
		event_id: &EventId,
		json: CanonicalJsonObject,
		rules: &RoomVersionRules,
	) -> Result<(Self, CanonicalJsonObject)> {
		let json = from_incoming_federation(room_id, event_id, json, rules);
		let pdu = Self::from_object_checked(json.clone(), rules)?;
		check_room_id(&pdu, room_id)?;
		Ok((pdu, json))
	}

	/// Validates a canonical PDU object before deserializing it.
	///
	/// Checks use the supplied room-version event-format rules. Successful
	/// validation returns the typed stored representation.
	pub fn from_object_checked(
		json: CanonicalJsonObject,
		rules: &RoomVersionRules,
	) -> Result<Self> {
		check_rules(&json, &rules.event_format)?;
		Self::from_object(json)
	}

	/// Deserializes a canonical JSON object into a stored PDU.
	///
	/// The object is wrapped as a canonical JSON value before typed
	/// deserialization. No room-version format checks are performed.
	pub fn from_object(json: CanonicalJsonObject) -> Result<Self> {
		let json = CanonicalJsonValue::Object(json);
		Self::from_value(json)
	}

	/// Deserializes raw JSON through a canonical JSON value.
	///
	/// Canonical conversion normalizes integer and object representation before
	/// the PDU fields are decoded. No room-version format checks are
	/// performed.
	///
	/// # Panics
	///
	/// Panics if the raw JSON contains a value outside canonical JSON, such as
	/// a floating-point value or an integer outside the canonical range.
	pub fn from_raw_value(json: &RawJsonValue) -> Result<Self> {
		let json: CanonicalJsonValue = json.into();
		Self::from_value(json)
	}

	/// Deserializes a canonical JSON value into a stored PDU.
	///
	/// The input must contain the fields required by `Pdu`. No room-version
	/// format checks are performed before deserialization.
	pub fn from_value(json: CanonicalJsonValue) -> Result<Self> {
		serde_json::from_value(json.into()).map_err(Into::into)
	}

	/// Deserializes raw JSON directly into a stored PDU.
	///
	/// This path uses `Pdu`'s Serde representation without first canonicalizing
	/// the input. Callers that require canonical validation should use a
	/// checked constructor.
	pub fn from_raw_json(json: &RawJsonValue) -> Result<Self> {
		Self::deserialize(json).map_err(Into::into)
	}

	/// MSC4025: a pruned clone per the redaction rules, carrying no
	/// `redacted_because`; no redaction event exists for a serve-time
	/// erasure.
	pub fn redacted(&self, rules: &RedactionRules) -> Result<Self> {
		let mut object = self.to_canonical_object();

		redact_in_place(&mut object, rules, None)
			.map_err(|e| err!("Failed to redact event: {e}"))?;

		Self::from_object(object)
	}
}

impl Event for Pdu
where
	Self: Send + Sync + 'static,
{
	#[inline]
	fn auth_events(&self) -> impl DoubleEndedIterator<Item = &EventId> + Clone + Send + '_ {
		self.auth_events.iter().map(AsRef::as_ref)
	}

	#[inline]
	fn auth_events_into(
		self,
	) -> impl IntoIterator<IntoIter = impl Iterator<Item = OwnedEventId>> + Send {
		self.auth_events.into_iter()
	}

	#[inline]
	fn content(&self) -> &RawJsonValue { self.content.json() }

	#[inline]
	fn event_id(&self) -> &EventId { &self.event_id }

	#[inline]
	fn origin_server_ts(&self) -> MilliSecondsSinceUnixEpoch {
		MilliSecondsSinceUnixEpoch(self.origin_server_ts)
	}

	#[inline]
	fn prev_events(&self) -> impl DoubleEndedIterator<Item = &EventId> + Clone + Send + '_ {
		self.prev_events.iter().map(AsRef::as_ref)
	}

	#[inline]
	fn redacts(&self) -> Option<&EventId> { self.redacts.as_deref() }

	#[cfg(test)]
	#[inline]
	fn rejected(&self) -> bool { self.rejected }

	#[cfg(not(test))]
	#[inline]
	fn rejected(&self) -> bool { false }

	#[inline]
	fn room_id(&self) -> &RoomId { &self.room_id }

	#[inline]
	fn sender(&self) -> &UserId { &self.sender }

	#[inline]
	fn state_key(&self) -> Option<&str> { self.state_key.as_deref() }

	#[inline]
	fn kind(&self) -> &TimelineEventType { &self.kind }

	#[inline]
	fn unsigned(&self) -> Option<&RawJsonValue> { self.unsigned.as_ref().map(Unsigned::json) }

	#[inline]
	fn as_mut_pdu(&mut self) -> &mut Pdu { self }

	#[inline]
	fn as_pdu(&self) -> &Pdu { self }

	#[inline]
	fn into_pdu(self) -> Pdu { self }

	#[inline]
	fn is_owned(&self) -> bool { true }
}

impl Event for &Pdu
where
	Self: Send,
{
	#[inline]
	fn auth_events(&self) -> impl DoubleEndedIterator<Item = &EventId> + Clone + Send + '_ {
		self.auth_events.iter().map(AsRef::as_ref)
	}

	#[inline]
	fn auth_events_into(
		self,
	) -> impl IntoIterator<IntoIter = impl Iterator<Item = OwnedEventId>> + Send {
		self.auth_events.iter().map(ToOwned::to_owned)
	}

	#[inline]
	fn content(&self) -> &RawJsonValue { self.content.json() }

	#[inline]
	fn event_id(&self) -> &EventId { &self.event_id }

	#[inline]
	fn origin_server_ts(&self) -> MilliSecondsSinceUnixEpoch {
		MilliSecondsSinceUnixEpoch(self.origin_server_ts)
	}

	#[inline]
	fn prev_events(&self) -> impl DoubleEndedIterator<Item = &EventId> + Clone + Send + '_ {
		self.prev_events.iter().map(AsRef::as_ref)
	}

	#[inline]
	fn redacts(&self) -> Option<&EventId> { self.redacts.as_deref() }

	#[cfg(test)]
	#[inline]
	fn rejected(&self) -> bool { self.rejected }

	#[cfg(not(test))]
	#[inline]
	fn rejected(&self) -> bool { false }

	#[inline]
	fn room_id(&self) -> &RoomId { &self.room_id }

	#[inline]
	fn sender(&self) -> &UserId { &self.sender }

	#[inline]
	fn state_key(&self) -> Option<&str> { self.state_key.as_deref() }

	#[inline]
	fn kind(&self) -> &TimelineEventType { &self.kind }

	#[inline]
	fn unsigned(&self) -> Option<&RawJsonValue> { self.unsigned.as_ref().map(Unsigned::json) }

	#[inline]
	fn as_pdu(&self) -> &Pdu { self }

	#[inline]
	fn into_pdu(self) -> Pdu { self.clone() }

	#[inline]
	fn is_owned(&self) -> bool { false }
}

/// Prevent derived equality which wouldn't limit itself to event_id
impl Eq for Pdu {}

/// Equality determined by the Pdu's ID, not the memory representations.
impl PartialEq for Pdu {
	fn eq(&self, other: &Self) -> bool { self.event_id == other.event_id }
}

/// Ordering determined by the Pdu's ID, not the memory representations.
impl Ord for Pdu {
	fn cmp(&self, other: &Self) -> Ordering { self.event_id.cmp(&other.event_id) }
}

/// Ordering determined by the Pdu's ID, not the memory representations.
impl PartialOrd for Pdu {
	fn partial_cmp(&self, other: &Self) -> Option<Ordering> { Some(self.cmp(other)) }
}