Derive Serialize in ruma_events!, use json EventType string for event_type field

Co-authored-by: Jonas Platte <jplatte+git@posteo.de>

ruma-events-macros/src/gen.rs

@@ -1,5 +1,4 @@
 //! Details of generating code for the `ruma_event` procedural macro.
-
 use proc_macro2::{Span, TokenStream};
 use quote::{format_ident, quote, quote_spanned, ToTokens};
 use syn::{
@@ -7,7 +6,7 @@ use syn::{
     parse_quote,
     punctuated::Punctuated,
     spanned::Spanned,
-    Attribute, Field, Ident, Path, Token, Type,
+    Attribute, Field, Ident, LitStr, Token, Type,
 };
 
 use crate::parse::{Content, EventKind, RumaEventInput};
@@ -25,7 +24,7 @@ pub struct RumaEvent {
 
     /// The variant of `ruma_events::EventType` for this event, determined by the `event_type`
     /// field.
-    event_type: Path,
+    event_type: LitStr,
 
     /// Struct fields of the event.
     fields: Vec<Field>,
@@ -80,10 +79,12 @@ impl ToTokens for RumaEvent {
         let content_name = &self.content_name;
         let event_fields = &self.fields;
 
-        let event_type = {
-            let event_type = &self.event_type;
+        let event_type_variant = {
+            let event_type = to_camel_case(self.event_type.value());
+            let variant = Ident::new(&event_type, event_type.span());
+
             quote! {
-                #event_type
+                ::ruma_events::EventType::#variant
             }
         };
 
@@ -315,7 +316,7 @@ impl ToTokens for RumaEvent {
 
                 /// The type of the event.
                 fn event_type(&self) -> ::ruma_events::EventType {
-                    #event_type
+                    #event_type_variant
                 }
             }
 
@@ -406,6 +407,16 @@ fn is_option(ty: &Type) -> bool {
     }
 }
 
+/// Splits the given `event_type` string on `.` and `_` removing the `m.` then
+/// camel casing to give the `EventType` variant.
+fn to_camel_case(name: String) -> String {
+    assert_eq!(&name[..2], "m.");
+    name[2..]
+        .split(&['.', '_'] as &[char])
+        .map(|s| s.chars().next().unwrap().to_uppercase().to_string() + &s[1..])
+        .collect()
+}
+
 /// A wrapper around `syn::Field` that makes it possible to parse `Punctuated<Field, Token![,]>`
 /// from a `TokenStream`.
 ///

ruma-events-macros/src/parse.rs

@@ -1,14 +1,10 @@
 //! Details of parsing input for the `ruma_event` procedural macro.
 
-use proc_macro2::Span;
-
 use syn::{
     braced,
     parse::{self, Parse, ParseStream},
-    punctuated::Punctuated,
     token::Colon,
-    Attribute, Expr, Field, FieldValue, Ident, Member, Path, PathArguments, PathSegment, Token,
-    TypePath,
+    Attribute, Expr, ExprLit, Field, FieldValue, Ident, Lit, LitStr, Member, Token, TypePath,
 };
 
 /// The entire `ruma_event!` macro structure directly as it appears in the source code..
@@ -22,9 +18,11 @@ pub struct RumaEventInput {
     /// The kind of event, determiend by the `kind` field.
     pub kind: EventKind,
 
-    /// The variant of `ruma_events::EventType` for this event, determined by the `event_type`
-    /// field.
-    pub event_type: Path,
+    /// The value for the `type` field in the JSON representation of this event. 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 event_type: LitStr,
 
     /// Additional named struct fields in the top level event struct.
     pub fields: Option<Vec<Field>>,
@@ -98,35 +96,13 @@ impl Parse for RumaEventInput {
 
                         kind = Some(event_kind);
                     } else if ident == "event_type" {
-                        match field_value.expr {
-                            Expr::Path(expr_path) => {
-                                if expr_path.path.segments.len() != 1 {
-                                    panic!("value of field `event_type` is required to be an ident by `ruma_event!`");
-                                }
-
-                                let path = expr_path.path;
-                                let variant = path.segments.first().unwrap();
-
-                                let mut punctuated = Punctuated::new();
-                                punctuated.push(PathSegment {
-                                    ident: Ident::new("ruma_events", Span::call_site()),
-                                    arguments: PathArguments::None,
-                                });
-                                punctuated.push(PathSegment {
-                                    ident: Ident::new("EventType", Span::call_site()),
-                                    arguments: PathArguments::None,
-                                });
-                                punctuated.push(variant.clone());
-
-                                event_type = Some(Path {
-                                    leading_colon: Some(Default::default()),
-                                    segments: punctuated,
-                                });
-                            }
+                        event_type = Some(match field_value.expr {
+                            Expr::Lit(ExprLit { lit: Lit::Str(s), .. }) => s,
+                            // TODO: Span info
                             _ => panic!(
-                                "value of field `event_type` is required to be an ident by `ruma_event!`"
+                                "value of field `event_type` is required to be a string literal by `ruma_event!`"
                             ),
-                        }
+                        })
                     } else {
                         panic!("unexpected field-value pair with field name `{}`", ident);
                     }

src/call/answer.rs

@@ -9,7 +9,7 @@ ruma_event! {
     /// This event is sent by the callee when they wish to answer the call.
     AnswerEvent {
         kind: RoomEvent,
-        event_type: CallAnswer,
+        event_type: "m.call.answer",
         content: {
             /// The VoIP session description object. The session description type must be *answer*.
             pub answer: SessionDescription,

src/call/candidates.rs

@@ -10,7 +10,7 @@ ruma_event! {
     /// communicate.
     CandidatesEvent {
         kind: RoomEvent,
-        event_type: CallCandidates,
+        event_type: "m.call.candidates",
         content: {
             /// The ID of the call this event relates to.
             pub call_id: String,

src/call/hangup.rs

@@ -9,7 +9,7 @@ ruma_event! {
     /// the call has has been established or before to abort the call.
     HangupEvent {
         kind: RoomEvent,
-        event_type: CallHangup,
+        event_type: "m.call.hangup",
         content: {
             /// The ID of the call this event relates to.
             pub call_id: String,

src/call/invite.rs

@@ -9,7 +9,7 @@ ruma_event! {
     /// This event is sent by the caller when they wish to establish a call.
     InviteEvent {
         kind: RoomEvent,
-        event_type: CallInvite,
+        event_type: "m.call.invite",
         content: {
             /// A unique identifer for the call.
             pub call_id: String,

src/direct.rs

@@ -9,7 +9,7 @@ ruma_event! {
     /// Informs the client about the rooms that are considered direct by a user.
     DirectEvent {
         kind: Event,
-        event_type: Direct,
+        event_type: "m.direct",
         content_type_alias: {
             /// The payload for `DirectEvent`.
             ///

src/dummy.rs

@@ -16,7 +16,7 @@ ruma_event! {
     /// sending client receiving keys over the newly established session.
     DummyEvent {
         kind: Event,
-        event_type: Dummy,
+        event_type: "m.dummy",
         content_type_alias: {
             /// The payload for `DummyEvent`.
             Empty

src/forwarded_room_key.rs

@@ -11,7 +11,7 @@ ruma_event! {
     /// Typically it is encrypted as an *m.room.encrypted* event, then sent as a to-device event.
     ForwardedRoomKeyEvent {
         kind: Event,
-        event_type: ForwardedRoomKey,
+        event_type: "m.forwarded_room_key",
         content: {
             /// The encryption algorithm the key in this event is to be used with.
             pub algorithm: Algorithm,

src/fully_read.rs

@@ -10,7 +10,7 @@ ruma_event! {
     /// for.
     FullyReadEvent {
         kind: Event,
-        event_type: FullyRead,
+        event_type: "m.fully_read",
         fields: {
             /// The unique identifier for the room associated with this event.
             ///

src/key/verification/accept.rs

@@ -13,7 +13,7 @@ ruma_event! {
     /// Typically sent as a to-device event.
     AcceptEvent {
         kind: Event,
-        event_type: KeyVerificationAccept,
+        event_type: "m.key.verification.accept",
         content: {
             /// An opaque identifier for the verification process.
             ///

src/key/verification/cancel.rs

@@ -14,7 +14,7 @@ ruma_event! {
     /// Typically sent as a to-device event.
     CancelEvent {
         kind: Event,
-        event_type: KeyVerificationCancel,
+        event_type: "m.key.verification.cancel",
         content: {
             /// The opaque identifier for the verification process/request.
             pub transaction_id: String,

src/key/verification/key.rs

@@ -8,7 +8,7 @@ ruma_event! {
     /// Typically sent as a to-device event.
     KeyEvent {
         kind: Event,
-        event_type: KeyVerificationKey,
+        event_type: "m.key.verification.key",
         content: {
             /// An opaque identifier for the verification process.
             ///

src/key/verification/mac.rs

@@ -10,7 +10,7 @@ ruma_event! {
     /// Typically sent as a to-device event.
     MacEvent {
         kind: Event,
-        event_type: KeyVerificationMac,
+        event_type: "m.key.verification.mac",
         content: {
             /// An opaque identifier for the verification process.
             ///

src/key/verification/request.rs

@@ -12,7 +12,7 @@ ruma_event! {
     /// Typically sent as a to-device event.
     RequestEvent {
         kind: Event,
-        event_type: KeyVerificationRequest,
+        event_type: "m.key.verification.request",
         content: {
             /// The device ID which is initiating the request.
             pub from_device: DeviceId,

src/presence.rs

@@ -9,7 +9,7 @@ ruma_event! {
     /// Informs the client of a user's presence state change.
     PresenceEvent {
         kind: Event,
-        event_type: Presence,
+        event_type: "m.presence",
         fields: {
             /// The unique identifier for the user associated with this event.
             pub sender: UserId,

src/push_rules.rs

@@ -19,7 +19,7 @@ ruma_event! {
     /// Describes all push rules for a user.
     PushRulesEvent {
         kind: Event,
-        event_type: PushRules,
+        event_type: "m.push_rules",
         content: {
             /// The global ruleset.
             pub global: Ruleset,

src/receipt.rs

@@ -11,7 +11,7 @@ ruma_event! {
     /// Informs the client of new receipts.
     ReceiptEvent {
         kind: Event,
-        event_type: Receipt,
+        event_type: "m.receipt",
         fields: {
             /// The unique identifier for the room associated with this event.
             ///

src/room/aliases.rs

@@ -7,7 +7,7 @@ ruma_event! {
     /// Informs the room about what room aliases it has been given.
     AliasesEvent {
         kind: StateEvent,
-        event_type: RoomAliases,
+        event_type: "m.room.aliases",
         content: {
             /// A list of room aliases.
             pub aliases: Vec<RoomAliasId>,

src/room/avatar.rs

@@ -10,7 +10,7 @@ ruma_event! {
     /// This can be displayed alongside the room information.
     AvatarEvent {
         kind: StateEvent,
-        event_type: RoomAvatar,
+        event_type: "m.room.avatar",
         content: {
             /// Information about the avatar image.
             #[serde(skip_serializing_if = "Option::is_none")]

src/room/create.rs

@@ -13,7 +13,7 @@ ruma_event! {
     /// events.
     CreateEvent {
         kind: StateEvent,
-        event_type: RoomCreate,
+        event_type: "m.room.create",
         content: {
             /// The `user_id` of the room creator. This is set by the homeserver.
             pub creator: UserId,

src/room/encryption.rs

@@ -9,7 +9,7 @@ ruma_event! {
     /// Defines how messages sent in this room should be encrypted.
     EncryptionEvent {
         kind: StateEvent,
-        event_type: RoomEncryption,
+        event_type: "m.room.encryption",
         content: {
             /// The encryption algorithm to be used to encrypt messages sent in this room.
             ///

src/room/guest_access.rs

@@ -10,7 +10,7 @@ ruma_event! {
     /// servers should act as if it is present and has the value `GuestAccess::Forbidden`.
     GuestAccessEvent {
         kind: StateEvent,
-        event_type: RoomGuestAccess,
+        event_type: "m.room.guest_access",
         content: {
             /// A policy for guest user access to a room.
             pub guest_access: GuestAccess,

src/room/history_visibility.rs

@@ -8,7 +8,7 @@ ruma_event! {
     /// from before they joined.
     HistoryVisibilityEvent {
         kind: StateEvent,
-        event_type: RoomHistoryVisibility,
+        event_type: "m.room.history_visibility",
         content: {
             /// Who can see the room history.
             pub history_visibility: HistoryVisibility,

src/room/join_rules.rs

@@ -7,7 +7,7 @@ ruma_event! {
     /// Describes how users are allowed to join the room.
     JoinRulesEvent {
         kind: StateEvent,
-        event_type: RoomJoinRules,
+        event_type: "m.room.join_rules",
         content: {
             /// The type of rules used for users wishing to join this room.
             pub join_rule: JoinRule,

src/room/member.rs

@@ -34,7 +34,7 @@ ruma_event! {
     /// must be assumed as leave.
     MemberEvent {
         kind: StateEvent,
-        event_type: RoomMember,
+        event_type: "m.room.member",
         content: {
             /// The avatar URL for this user, if any. This is added by the homeserver.
             #[serde(skip_serializing_if = "Option::is_none")]

src/room/message/feedback.rs

@@ -11,7 +11,7 @@ ruma_event! {
     /// not recognize this event.
     FeedbackEvent {
         kind: RoomEvent,
-        event_type: RoomMessageFeedback,
+        event_type: "m.room.message.feedback",
         content: {
             /// The event that this feedback is related to.
             pub target_event_id: EventId,

src/room/pinned_events.rs

@@ -7,7 +7,7 @@ ruma_event! {
     /// Used to "pin" particular events in a room for other participants to review later.
     PinnedEventsEvent {
         kind: StateEvent,
-        event_type: RoomPinnedEvents,
+        event_type: "m.room.pinned_events",
         content: {
             /// An ordered list of event IDs to pin.
             pub pinned: Vec<EventId>,

src/room/redaction.rs

@@ -7,7 +7,7 @@ ruma_event! {
     /// A redaction of an event.
     RedactionEvent {
         kind: RoomEvent,
-        event_type: RoomRedaction,
+        event_type: "m.room.redaction",
         fields: {
             /// The ID of the event that was redacted.
             pub redacts: EventId,

src/room/third_party_invite.rs

@@ -11,7 +11,7 @@ ruma_event! {
     /// Any user who can present that signature may use this invitation to join the target room.
     ThirdPartyInviteEvent {
         kind: StateEvent,
-        event_type: RoomThirdPartyInvite,
+        event_type: "m.room.third_party_invite",
         content: {
             /// A user-readable string which represents the user who has been invited.
             pub display_name: String,

src/room/tombstone.rs

@@ -8,7 +8,7 @@ ruma_event! {
     /// clients should go there.
     TombstoneEvent {
         kind: StateEvent,
-        event_type: RoomTombstone,
+        event_type: "m.room.tombstone",
         content: {
             /// A server-defined message.
             pub body: String,

src/room/topic.rs

@@ -6,7 +6,7 @@ ruma_event! {
     /// A topic is a short message detailing what is currently being discussed in the room.
     TopicEvent {
         kind: StateEvent,
-        event_type: RoomTopic,
+        event_type: "m.room.topic",
         content: {
             /// The topic text.
             pub topic: String,

src/room_key.rs

@@ -11,7 +11,7 @@ ruma_event! {
     /// Typically it is encrypted as an *m.room.encrypted* event, then sent as a to-device event.
     RoomKeyEvent {
         kind: Event,
-        event_type: RoomKey,
+        event_type: "m.room_key",
         content: {
             /// The encryption algorithm the key in this event is to be used with.
             ///

src/room_key_request.rs

@@ -12,7 +12,7 @@ ruma_event! {
     /// It is sent as an unencrypted to-device event.
     RoomKeyRequestEvent {
         kind: Event,
-        event_type: RoomKeyRequest,
+        event_type: "m.room_key_request",
         content: {
             /// Whether this is a new key request or a cancellation of a previous request.
             pub action: Action,

src/sticker.rs

@@ -8,7 +8,7 @@ ruma_event! {
     /// A sticker message.
     StickerEvent {
         kind: RoomEvent,
-        event_type: Sticker,
+        event_type: "m.sticker",
         content: {
             /// A textual representation or associated description of the sticker image. This could
             /// be the alt text of the original image, or a message to accompany and further

src/tag.rs

@@ -9,7 +9,7 @@ ruma_event! {
     /// Informs the client of tags on a room.
     TagEvent {
         kind: Event,
-        event_type: Tag,
+        event_type: "m.tag",
         content: {
             /// A map of tag names to tag info.
             pub tags: HashMap<String, TagInfo>,

src/typing.rs

@@ -7,7 +7,7 @@ ruma_event! {
     /// Informs the client of the list of users currently typing.
     TypingEvent {
         kind: Event,
-        event_type: Typing,
+        event_type: "m.typing",
         fields: {
             /// The unique identifier for the room associated with this event.
             ///

tests/ruma_events_macros.rs

@@ -14,7 +14,7 @@ mod common_case {
         /// Informs the room about what room aliases it has been given.
         AliasesEvent {
             kind: StateEvent,
-            event_type: RoomAliases,
+            event_type: "m.room.aliases",
             content: {
                 /// A list of room aliases.
                 pub aliases: Vec<ruma_identifiers::RoomAliasId>,
@@ -126,7 +126,7 @@ mod extra_fields {
         /// A redaction of an event.
         RedactionEvent {
             kind: RoomEvent,
-            event_type: RoomRedaction,
+            event_type: "m.room.redaction",
             fields: {
                 /// The ID of the event that was redacted.
                 pub redacts: ruma_identifiers::EventId
@@ -174,7 +174,7 @@ mod type_alias {
         /// Informs the client about the rooms that are considered direct by a user.
         DirectEvent {
             kind: Event,
-            event_type: Direct,
+            event_type: "m.direct",
             content_type_alias: {
                 /// The payload of a `DirectEvent`.
                 ///