ruwuma/ruma-events-macros/src/event_parse.rs

232 lines
8.3 KiB
Rust

//! Implementation of event enum and event content enum macros.
use std::fmt;
use proc_macro2::Span;
use quote::format_ident;
use syn::{
parse::{self, Parse, ParseStream},
Attribute, Expr, ExprLit, Ident, Lit, LitStr, Token,
};
/// Custom keywords for the `event_enum!` macro
mod kw {
syn::custom_keyword!(kind);
syn::custom_keyword!(events);
}
// If the variants of this enum change `to_event_path` needs to be updated as well.
#[derive(Clone, Copy, Eq, PartialEq)]
pub enum EventKindVariation {
Full,
Sync,
Stripped,
Initial,
Redacted,
RedactedSync,
RedactedStripped,
}
impl fmt::Display for EventKindVariation {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
EventKindVariation::Full => write!(f, ""),
EventKindVariation::Sync => write!(f, "Sync"),
EventKindVariation::Stripped => write!(f, "Stripped"),
EventKindVariation::Initial => write!(f, "Initial"),
EventKindVariation::Redacted => write!(f, "Redacted"),
EventKindVariation::RedactedSync => write!(f, "RedactedSync"),
EventKindVariation::RedactedStripped => write!(f, "RedactedStripped"),
}
}
}
impl EventKindVariation {
pub fn is_redacted(&self) -> bool {
matches!(self, Self::Redacted | Self::RedactedSync | Self::RedactedStripped)
}
pub fn to_full_variation(&self) -> Self {
match self {
EventKindVariation::Redacted
| EventKindVariation::RedactedSync
| EventKindVariation::RedactedStripped => EventKindVariation::Redacted,
EventKindVariation::Full
| EventKindVariation::Sync
| EventKindVariation::Stripped
| EventKindVariation::Initial => EventKindVariation::Full,
}
}
}
// If the variants of this enum change `to_event_path` needs to be updated as well.
#[derive(Debug, Eq, PartialEq)]
pub enum EventKind {
Basic,
Ephemeral,
Message,
State,
ToDevice,
Redaction,
Presence,
}
impl fmt::Display for EventKind {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
EventKind::Basic => write!(f, "BasicEvent"),
EventKind::Ephemeral => write!(f, "EphemeralRoomEvent"),
EventKind::Message => write!(f, "MessageEvent"),
EventKind::State => write!(f, "StateEvent"),
EventKind::ToDevice => write!(f, "ToDeviceEvent"),
EventKind::Redaction => write!(f, "RedactionEvent"),
EventKind::Presence => write!(f, "PresenceEvent"),
}
}
}
impl EventKind {
pub fn is_state(&self) -> bool {
matches!(self, Self::State)
}
pub fn is_message(&self) -> bool {
matches!(self, Self::Message)
}
pub fn to_event_ident(&self, var: &EventKindVariation) -> Option<Ident> {
use EventKindVariation as V;
// this match is only used to validate the input
match (self, var) {
(_, V::Full)
| (Self::Ephemeral, V::Sync)
| (Self::Message, V::Sync)
| (Self::State, V::Sync)
| (Self::State, V::Stripped)
| (Self::State, V::Initial)
| (Self::Message, V::Redacted)
| (Self::State, V::Redacted)
| (Self::Message, V::RedactedSync)
| (Self::State, V::RedactedSync)
| (Self::State, V::RedactedStripped) => {
Some(Ident::new(&format!("{}{}", var, self), Span::call_site()))
}
_ => None,
}
}
pub fn to_event_enum_ident(&self, var: &EventKindVariation) -> Option<Ident> {
Some(format_ident!("Any{}", self.to_event_ident(var)?))
}
/// `Any[kind]EventContent`
pub fn to_content_enum(&self) -> Ident {
Ident::new(&format!("Any{}Content", self), Span::call_site())
}
}
impl Parse for EventKind {
fn parse(input: ParseStream) -> syn::Result<Self> {
let ident = input.parse::<Ident>()?;
Ok(match ident.to_string().as_str() {
"Basic" => EventKind::Basic,
"EphemeralRoom" => EventKind::Ephemeral,
"Message" => EventKind::Message,
"State" => EventKind::State,
"ToDevice" => EventKind::ToDevice,
id => {
return Err(syn::Error::new(
input.span(),
format!(
"valid event kinds are Basic, EphemeralRoom, Message, State, ToDevice \
found `{}`",
id
),
));
}
})
}
}
// This function is only used in the `Event` derive macro expansion code.
/// Validates the given `ident` is a valid event struct name and returns a tuple of enums
/// representing the name.
pub fn to_kind_variation(ident: &Ident) -> Option<(EventKind, EventKindVariation)> {
let ident_str = ident.to_string();
match ident_str.as_str() {
"BasicEvent" => Some((EventKind::Basic, EventKindVariation::Full)),
"EphemeralRoomEvent" => Some((EventKind::Ephemeral, EventKindVariation::Full)),
"SyncEphemeralRoomEvent" => Some((EventKind::Ephemeral, EventKindVariation::Sync)),
"MessageEvent" => Some((EventKind::Message, EventKindVariation::Full)),
"SyncMessageEvent" => Some((EventKind::Message, EventKindVariation::Sync)),
"RedactedMessageEvent" => Some((EventKind::Message, EventKindVariation::Redacted)),
"RedactedSyncMessageEvent" => Some((EventKind::Message, EventKindVariation::RedactedSync)),
"StateEvent" => Some((EventKind::State, EventKindVariation::Full)),
"SyncStateEvent" => Some((EventKind::State, EventKindVariation::Sync)),
"StrippedStateEvent" => Some((EventKind::State, EventKindVariation::Stripped)),
"InitialStateEvent" => Some((EventKind::State, EventKindVariation::Initial)),
"RedactedStateEvent" => Some((EventKind::State, EventKindVariation::Redacted)),
"RedactedSyncStateEvent" => Some((EventKind::State, EventKindVariation::RedactedSync)),
"RedactedStrippedStateEvent" => {
Some((EventKind::State, EventKindVariation::RedactedStripped))
}
"ToDeviceEvent" => Some((EventKind::ToDevice, EventKindVariation::Full)),
"PresenceEvent" => Some((EventKind::Presence, EventKindVariation::Full)),
"RedactionEvent" => Some((EventKind::Redaction, EventKindVariation::Full)),
"SyncRedactionEvent" => Some((EventKind::Redaction, EventKindVariation::Sync)),
_ => None,
}
}
/// The entire `event_enum!` macro structure directly as it appears in the source code.
pub struct EventEnumInput {
/// Outer attributes on the field, such as a docstring.
pub attrs: Vec<Attribute>,
/// The name of the event.
pub name: EventKind,
/// An array of valid matrix event types.
///
/// This will generate the variants of the event type "name". There needs to be a corresponding
/// variant in `ruma_events::EventType` for this event (converted to a valid Rust-style type
/// name by stripping `m.`, replacing the remaining dots by underscores and then converting from
/// snake_case to CamelCase).
pub events: Vec<LitStr>,
}
impl Parse for EventEnumInput {
fn parse(input: ParseStream<'_>) -> parse::Result<Self> {
let attrs = input.call(Attribute::parse_outer)?;
// "name" field
input.parse::<kw::kind>()?;
input.parse::<Token![:]>()?;
// the name of our event enum
let name = input.parse::<EventKind>()?;
input.parse::<Token![,]>()?;
// "events" field
input.parse::<kw::events>()?;
input.parse::<Token![:]>()?;
// an array of event names `["m.room.whatever", ...]`
let ev_array = input.parse::<syn::ExprArray>()?;
let events = ev_array
.elems
.into_iter()
.map(|item| {
if let Expr::Lit(ExprLit { lit: Lit::Str(lit_str), .. }) = item {
Ok(lit_str)
} else {
let msg = "values of field `events` are required to be a string literal";
Err(syn::Error::new_spanned(item, msg))
}
})
.collect::<syn::Result<_>>()?;
Ok(Self { attrs, name, events })
}
}