Move Outgoing from ruma-api to ruma-common

The derive macro moves from ruma-api-macros to a new ruma-common-macros
crate likewise.

ruma-api-macros/src/api.rs

@@ -170,7 +170,10 @@ impl ToTokens for Api {
                 TokenStream::new()
             };
             quote! {
-                let request_body: <RequestBody #body_lifetimes as #ruma_api_import::Outgoing>::Incoming =
+                let request_body: <
+                    RequestBody #body_lifetimes
+                    as #ruma_api_import::exports::ruma_common::Outgoing
+                >::Incoming =
                     #ruma_api_import::try_deserialize!(
                         request,
                         #ruma_api_import::exports::serde_json::from_slice(request.body().as_slice())
@@ -202,7 +205,10 @@ impl ToTokens for Api {
             || self.response.newtype_body_field().is_some()
         {
             quote! {
-                let response_body: <ResponseBody as #ruma_api_import::Outgoing>::Incoming =
+                let response_body: <
+                    ResponseBody
+                    as #ruma_api_import::exports::ruma_common::Outgoing
+                >::Incoming =
                     #ruma_api_import::try_deserialize!(
                         response,
                         #ruma_api_import::exports::serde_json::from_slice(response.body().as_slice()),
@@ -328,7 +334,8 @@ impl ToTokens for Api {
                 for Request #request_lifetimes
             {
                 type EndpointError = #error;
-                type IncomingResponse = <Response as #ruma_api_import::Outgoing>::Incoming;
+                type IncomingResponse =
+                    <Response as #ruma_api_import::exports::ruma_common::Outgoing>::Incoming;
 
                 #[doc = #metadata_doc]
                 const METADATA: #ruma_api_import::Metadata = __METADATA;

ruma-api-macros/src/api/request.rs

@@ -470,7 +470,7 @@ impl ToTokens for Request {
                     /// Data in the request body.
                     #[derive(
                         Debug,
-                        #import_path::Outgoing,
+                        #import_path::exports::ruma_common::Outgoing,
                         #import_path::exports::serde::Serialize,
                         #derive_deserialize
                     )]
@@ -490,7 +490,7 @@ impl ToTokens for Request {
                 /// Data in the request's query string.
                 #[derive(
                     Debug,
-                    #import_path::Outgoing,
+                    #import_path::exports::ruma_common::Outgoing,
                     #import_path::exports::serde::Serialize,
                     #derive_deserialize
                 )]
@@ -508,7 +508,7 @@ impl ToTokens for Request {
                 /// Data in the request's query string.
                 #[derive(
                     Debug,
-                    #import_path::Outgoing,
+                    #import_path::exports::ruma_common::Outgoing,
                     #import_path::exports::serde::Serialize,
                     #derive_deserialize
                 )]
@@ -521,7 +521,7 @@ impl ToTokens for Request {
         };
 
         let request = quote! {
-            #[derive(Debug, Clone, #import_path::Outgoing)]
+            #[derive(Debug, Clone, #import_path::exports::ruma_common::Outgoing)]
             #[cfg_attr(not(feature = "unstable-exhaustive-types"), non_exhaustive)]
             #[incoming_derive(!Deserialize)]
             #( #struct_attributes )*

ruma-api-macros/src/api/response.rs

@@ -310,7 +310,7 @@ impl ToTokens for Response {
             /// Data in the response body.
             #[derive(
                 Debug,
-                #import_path::Outgoing,
+                #import_path::exports::ruma_common::Outgoing,
                 #import_path::exports::serde::Deserialize,
                 #import_path::exports::serde::Serialize,
             )]
@@ -318,7 +318,7 @@ impl ToTokens for Response {
         };
 
         let response = quote! {
-            #[derive(Debug, Clone, #import_path::Outgoing)]
+            #[derive(Debug, Clone, #import_path::exports::ruma_common::Outgoing)]
             #[cfg_attr(not(feature = "unstable-exhaustive-types"), non_exhaustive)]
             #[incoming_derive(!Deserialize)]
             #( #struct_attributes )*

ruma-api-macros/src/lib.rs

@@ -15,15 +15,11 @@ use std::convert::TryFrom as _;
 
 use proc_macro::TokenStream;
 use quote::ToTokens;
-use syn::{parse_macro_input, DeriveInput};
+use syn::parse_macro_input;
 
-use self::{
+use self::api::{Api, RawApi};
-    api::{Api, RawApi},
-    derive_outgoing::expand_derive_outgoing,
-};
 
 mod api;
-mod derive_outgoing;
 mod util;
 
 #[proc_macro]
@@ -34,50 +30,3 @@ pub fn ruma_api(input: TokenStream) -> TokenStream {
         Err(err) => err.to_compile_error().into(),
     }
 }
-
-/// Derive the `Outgoing` trait, possibly generating an 'Incoming' version of the struct this
-/// derive macro is used on. Specifically, if no lifetime variables are used on any of the fields
-/// of the struct, this simple implementation will be generated:
-///
-/// ```ignore
-/// impl Outgoing for MyType {
-///     type Incoming = Self;
-/// }
-/// ```
-
-/* TODO: Extend docs. Previously:
-
-If, however, `#[wrap_incoming]` is used (which is the only reason you should ever use this
-derive macro manually), a new struct `IncomingT` (where `T` is the type this derive is used on)
-is generated, with all of the fields with `#[wrap_incoming]` replaced:
-
-```ignore
-#[derive(Outgoing)]
-struct MyType {
-    pub foo: Foo,
-    #[wrap_incoming]
-    pub bar: Bar,
-    #[wrap_incoming(Baz)]
-    pub baz: Option<Baz>,
-    #[wrap_incoming(with EventResult)]
-    pub x: XEvent,
-    #[wrap_incoming(YEvent with EventResult)]
-    pub ys: Vec<YEvent>,
-}
-
-// generated
-struct IncomingMyType {
-    pub foo: Foo,
-    pub bar: IncomingBar,
-    pub baz: Option<IncomingBaz>,
-    pub x: EventResult<XEvent>,
-    pub ys: Vec<EventResult<YEvent>>,
-}
-```
-
-*/
-#[proc_macro_derive(Outgoing, attributes(incoming_derive))]
-pub fn derive_outgoing(input: TokenStream) -> TokenStream {
-    let input = parse_macro_input!(input as DeriveInput);
-    expand_derive_outgoing(input).unwrap_or_else(|err| err.to_compile_error()).into()
-}

ruma-api-macros/src/util.rs

@@ -285,7 +285,10 @@ pub(crate) fn extract_request_query(request: &Request, import_path: &TokenStream
         }
     } else if request.has_query_fields() {
         quote! {
-            let request_query: <RequestQuery as #import_path::Outgoing>::Incoming =
+            let request_query: <
+                RequestQuery
+                as #import_path::exports::ruma_common::Outgoing
+            >::Incoming =
                 #import_path::try_deserialize!(
                     request,
                     #import_path::exports::ruma_serde::urlencoded::from_str(

ruma-api/Cargo.toml

@@ -19,6 +19,7 @@ edition = "2018"
 http = "0.2.1"
 percent-encoding = "2.1.0"
 ruma-api-macros = { version = "=0.17.0-alpha.1", path = "../ruma-api-macros" }
+ruma-common = { version = "0.2.0", path = "../ruma-common" }
 ruma-identifiers = { version = "0.17.4", path = "../ruma-identifiers" }
 ruma-serde = { version = "0.2.3", path = "../ruma-serde" }
 serde = { version = "1.0.114", features = ["derive"] }

ruma-api/src/lib.rs

@@ -204,11 +204,9 @@ use http::Method;
 /// All request and response types also derive [`Outgoing`][Outgoing]. As such, to allow fallible
 /// deserialization, you can use the `#[wrap_incoming]` attribute. For details, see the
 /// documentation for [the derive macro](derive.Outgoing.html).
-// TODO: Explain the concept of fallible deserialization before jumping to `ruma_api::Outgoing`
+// TODO: Explain the concept of fallible deserialization before jumping to `ruma_common::Outgoing`
 pub use ruma_api_macros::ruma_api;
 
-pub use ruma_api_macros::Outgoing;
-
 pub mod error;
 /// This module is used to support the generated code from ruma-api-macros.
 /// It is not considered part of ruma-api's public API.
@@ -216,6 +214,7 @@ pub mod error;
 pub mod exports {
     pub use http;
     pub use percent_encoding;
+    pub use ruma_common;
     pub use ruma_serde;
     pub use serde;
     pub use serde_json;
@@ -223,18 +222,6 @@ pub mod exports {
 
 use error::{FromHttpRequestError, FromHttpResponseError, IntoHttpError};
 
-/// A type that can be sent to another party that understands the matrix protocol. If any of the
-/// fields of `Self` don't implement serde's `Deserialize`, you can derive this trait to generate a
-/// corresponding 'Incoming' type that supports deserialization. This is useful for things like
-/// ruma_events' `EventResult` type. For more details, see the [derive macro's documentation][doc].
-///
-/// [doc]: derive.Outgoing.html
-// TODO: Better explain how this trait relates to serde's traits
-pub trait Outgoing {
-    /// The 'Incoming' variant of `Self`.
-    type Incoming;
-}
-
 /// Gives users the ability to define their own serializable / deserializable errors.
 pub trait EndpointError: StdError + Sized + 'static {
     /// Tries to construct `Self` from an `http::Response`.

ruma-api/tests/manual_endpoint_impl.rs

@@ -3,16 +3,16 @@
 use std::{convert::TryFrom, ops::Deref};
 
 use http::{header::CONTENT_TYPE, method::Method};
-use ruma_identifiers::{RoomAliasId, RoomId};
-use serde::{Deserialize, Serialize};
-
 use ruma_api::{
     error::{
         FromHttpRequestError, FromHttpResponseError, IntoHttpError, RequestDeserializationError,
         ResponseDeserializationError, ServerError, Void,
     },
-    AuthScheme, IncomingRequest, Metadata, Outgoing, OutgoingRequest,
+    AuthScheme, IncomingRequest, Metadata, OutgoingRequest,
 };
+use ruma_common::Outgoing;
+use ruma_identifiers::{RoomAliasId, RoomId};
+use serde::{Deserialize, Serialize};
 
 /// A request to create a new room alias.
 #[derive(Debug)]

ruma-api/tests/ruma_api_lifetime.rs

@@ -1,5 +1,5 @@
 #[allow(unused)]
-#[derive(Copy, Clone, Debug, ruma_api::Outgoing, serde::Serialize)]
+#[derive(Copy, Clone, Debug, ruma_common::Outgoing, serde::Serialize)]
 pub struct OtherThing<'t> {
     some: &'t str,
     t: &'t [u8],

ruma-client-api/src/r0/account.rs

@@ -18,7 +18,7 @@ pub mod unbind_3pid;
 
 pub mod whoami;
 
-use ruma_api::Outgoing;
+use ruma_common::Outgoing;
 use serde::{Deserialize, Serialize};
 
 /// Additional authentication information for requestToken endpoints.

ruma-client-api/src/r0/filter.rs

@@ -6,7 +6,7 @@ pub mod get_filter;
 use std::fmt;
 
 use js_int::UInt;
-use ruma_api::Outgoing;
+use ruma_common::Outgoing;
 use ruma_identifiers::{RoomId, UserId};
 use serde::{
     de::{MapAccess, Visitor},

ruma-client-api/src/r0/membership.rs

@@ -14,8 +14,8 @@ pub mod unban_user;
 
 use std::collections::BTreeMap;
 
-use ruma_api::Outgoing;
 use ruma_common::thirdparty::Medium;
+use ruma_common::Outgoing;
 use ruma_identifiers::{ServerKeyId, ServerNameBox};
 use serde::Serialize;
 

ruma-client-api/src/r0/membership/invite_user.rs

@@ -7,7 +7,8 @@
 //! [invite-by-user-id]: https://matrix.org/docs/spec/client_server/r0.6.0#post-matrix-client-r0-rooms-roomid-invite
 //! [invite-by-3pid]: https://matrix.org/docs/spec/client_server/r0.6.0#id101
 
-use ruma_api::{ruma_api, Outgoing};
+use ruma_api::ruma_api;
+use ruma_common::Outgoing;
 use ruma_identifiers::{RoomId, UserId};
 use serde::Serialize;
 

ruma-client-api/src/r0/message/send_message_event.rs

@@ -7,8 +7,9 @@ use ruma_api::{
         FromHttpRequestError, FromHttpResponseError, IntoHttpError, RequestDeserializationError,
         ResponseDeserializationError, ServerError,
     },
-    AuthScheme, EndpointError, Metadata, Outgoing,
+    AuthScheme, EndpointError, Metadata,
 };
+use ruma_common::Outgoing;
 use ruma_events::{AnyMessageEventContent, EventContent as _};
 use ruma_identifiers::{EventId, RoomId};
 use serde::{Deserialize, Serialize};

ruma-client-api/src/r0/search/search_events.rs

@@ -3,8 +3,8 @@
 use std::collections::BTreeMap;
 
 use js_int::{uint, UInt};
-use ruma_api::{ruma_api, Outgoing};
+use ruma_api::ruma_api;
-use ruma_common::Raw;
+use ruma_common::{Outgoing, Raw};
 use ruma_events::{AnyRoomEvent, AnyStateEvent};
 use ruma_identifiers::{EventId, RoomId, UserId};
 use serde::{Deserialize, Serialize};

ruma-client-api/src/r0/session/login.rs

@@ -1,7 +1,7 @@
 //! [POST /_matrix/client/r0/login](https://matrix.org/docs/spec/client_server/r0.6.0#post-matrix-client-r0-login)
 
-use ruma_api::{ruma_api, Outgoing};
+use ruma_api::ruma_api;
-use ruma_common::thirdparty::Medium;
+use ruma_common::{thirdparty::Medium, Outgoing};
 use ruma_identifiers::{DeviceId, DeviceIdBox, ServerNameBox, UserId};
 use serde::{Deserialize, Serialize};
 

ruma-client-api/src/r0/session/login/user_serde.rs

@@ -1,8 +1,8 @@
 //! Helper module for the Serialize / Deserialize impl's for the User struct
 //! in the parent module.
 
-use ruma_api::Outgoing;
 use ruma_common::thirdparty::Medium;
+use ruma_common::Outgoing;
 use serde::Serialize;
 
 // The following three structs could just be used in place of the one in the parent module, but

ruma-client-api/src/r0/state/send_state_event_for_empty_key.rs

@@ -7,8 +7,9 @@ use ruma_api::{
         FromHttpRequestError, FromHttpResponseError, IntoHttpError, RequestDeserializationError,
         ResponseDeserializationError, ServerError,
     },
-    AuthScheme, EndpointError, Metadata, Outgoing,
+    AuthScheme, EndpointError, Metadata,
 };
+use ruma_common::Outgoing;
 use ruma_events::{AnyStateEventContent, EventContent as _};
 use ruma_identifiers::{EventId, RoomId};
 use serde::{Deserialize, Serialize};

ruma-client-api/src/r0/state/send_state_event_for_key.rs

@@ -7,8 +7,9 @@ use ruma_api::{
         FromHttpRequestError, FromHttpResponseError, IntoHttpError, RequestDeserializationError,
         ResponseDeserializationError, ServerError,
     },
-    AuthScheme, EndpointError, Metadata, Outgoing,
+    AuthScheme, EndpointError, Metadata,
 };
+use ruma_common::Outgoing;
 use ruma_events::{AnyStateEventContent, EventContent as _};
 use ruma_identifiers::{EventId, RoomId};
 use serde::{Deserialize, Serialize};

ruma-client-api/src/r0/sync/sync_events.rs

@@ -3,8 +3,8 @@
 use std::{collections::BTreeMap, time::Duration};
 
 use js_int::UInt;
-use ruma_api::{ruma_api, Outgoing};
+use ruma_api::ruma_api;
-use ruma_common::{presence::PresenceState, Raw};
+use ruma_common::{presence::PresenceState, Outgoing, Raw};
 use ruma_events::{
     presence::PresenceEvent, AnyBasicEvent, AnyStrippedStateEvent, AnySyncEphemeralRoomEvent,
     AnySyncRoomEvent, AnySyncStateEvent, AnyToDeviceEvent,

ruma-client-api/src/r0/uiaa.rs

@@ -5,7 +5,8 @@ use std::{
     fmt::{self, Display, Formatter},
 };
 
-use ruma_api::{error::ResponseDeserializationError, EndpointError, Outgoing};
+use ruma_api::{error::ResponseDeserializationError, EndpointError};
+use ruma_common::Outgoing;
 use serde::{Deserialize, Serialize};
 use serde_json::{
     from_slice as from_json_slice, to_vec as to_json_vec, value::RawValue as RawJsonValue,

ruma-common-macros/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+authors = ["Jonas Platte <jplatte@posteo.de>",]
+categories = ["api-bindings", "web-programming"]
+description = "Procedural macros for ruma-common."
+homepage = "https://www.ruma.io/"
+keywords = ["matrix", "chat", "messaging", "ruma"]
+license = "MIT"
+name = "ruma-common-macros"
+readme = "README.md"
+repository = "https://github.com/ruma/ruma"
+version = "0.2.0"
+edition = "2018"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+proc-macro2 = "1.0.19"
+quote = "1.0.7"
+syn = { version = "1.0.38", features = ["full", "extra-traits"] }
+proc-macro-crate = "0.1.5"

ruma-common-macros/LICENSE

@@ -0,0 +1,19 @@
+Copyright (c) 2020 Jonas Platte
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

ruma-common-macros/src/lib.rs

@@ -0,0 +1,55 @@
+use proc_macro::TokenStream;
+use syn::{parse_macro_input, DeriveInput};
+
+use outgoing::expand_derive_outgoing;
+
+mod outgoing;
+mod util;
+
+/// Derive the `Outgoing` trait, possibly generating an 'Incoming' version of the struct this
+/// derive macro is used on. Specifically, if no lifetime variables are used on any of the fields
+/// of the struct, this simple implementation will be generated:
+///
+/// ```ignore
+/// impl Outgoing for MyType {
+///     type Incoming = Self;
+/// }
+/// ```
+/*
+
+TODO: Extend docs. Previously:
+
+If, however, `#[wrap_incoming]` is used (which is the only reason you should ever use this
+derive macro manually), a new struct `IncomingT` (where `T` is the type this derive is used on)
+is generated, with all of the fields with `#[wrap_incoming]` replaced:
+
+```ignore
+#[derive(Outgoing)]
+struct MyType {
+    pub foo: Foo,
+    #[wrap_incoming]
+    pub bar: Bar,
+    #[wrap_incoming(Baz)]
+    pub baz: Option<Baz>,
+    #[wrap_incoming(with EventResult)]
+    pub x: XEvent,
+    #[wrap_incoming(YEvent with EventResult)]
+    pub ys: Vec<YEvent>,
+}
+
+// generated
+struct IncomingMyType {
+    pub foo: Foo,
+    pub bar: IncomingBar,
+    pub baz: Option<IncomingBaz>,
+    pub x: EventResult<XEvent>,
+    pub ys: Vec<EventResult<YEvent>>,
+}
+```
+
+*/
+#[proc_macro_derive(Outgoing, attributes(incoming_derive))]
+pub fn derive_outgoing(input: TokenStream) -> TokenStream {
+    let input = parse_macro_input!(input as DeriveInput);
+    expand_derive_outgoing(input).unwrap_or_else(|err| err.to_compile_error()).into()
+}

ruma-common-macros/src/outgoing.rs

@@ -9,7 +9,7 @@ use syn::{
     Token, Type, TypeGenerics, TypePath, TypeReference, TypeSlice, Variant,
 };
 
-use crate::util::import_ruma_api;
+use crate::util::import_ruma_common;
 
 enum StructKind {
     Struct,
@@ -23,7 +23,7 @@ enum DataKind {
 }
 
 pub fn expand_derive_outgoing(input: DeriveInput) -> syn::Result<TokenStream> {
-    let import_path = import_ruma_api();
+    let ruma_common = import_ruma_common();
 
     let mut derives = vec![quote! { Debug }];
     let mut derive_deserialize = true;
@@ -46,7 +46,7 @@ pub fn expand_derive_outgoing(input: DeriveInput) -> syn::Result<TokenStream> {
             }),
     );
     if derive_deserialize {
-        derives.push(quote! { #import_path::exports::serde::Deserialize });
+        derives.push(quote! { #ruma_common::exports::serde::Deserialize });
     }
 
     let input_attrs =
@@ -67,7 +67,7 @@ pub fn expand_derive_outgoing(input: DeriveInput) -> syn::Result<TokenStream> {
     };
 
     match data {
-        DataKind::Unit => Ok(impl_outgoing_with_incoming_self(&input, &import_path)),
+        DataKind::Unit => Ok(impl_outgoing_with_incoming_self(&input, &ruma_common)),
         DataKind::Enum(mut vars) => {
             let mut found_lifetime = false;
             for var in &mut vars {
@@ -82,7 +82,7 @@ pub fn expand_derive_outgoing(input: DeriveInput) -> syn::Result<TokenStream> {
             let (original_impl_gen, original_ty_gen, _) = input.generics.split_for_impl();
 
             if !found_lifetime {
-                return Ok(impl_outgoing_with_incoming_self(&input, &import_path));
+                return Ok(impl_outgoing_with_incoming_self(&input, &ruma_common));
             }
 
             let vis = input.vis;
@@ -98,7 +98,7 @@ pub fn expand_derive_outgoing(input: DeriveInput) -> syn::Result<TokenStream> {
                 #( #input_attrs )*
                 #vis enum #incoming_ident #ty_gen { #( #vars, )* }
 
-                impl #original_impl_gen #import_path::Outgoing for #original_ident #original_ty_gen {
+                impl #original_impl_gen #ruma_common::Outgoing for #original_ident #original_ty_gen {
                     type Incoming = #incoming_ident #impl_gen;
                 }
             })
@@ -115,7 +115,7 @@ pub fn expand_derive_outgoing(input: DeriveInput) -> syn::Result<TokenStream> {
             let (original_impl_gen, original_ty_gen, _) = input.generics.split_for_impl();
 
             if !found_lifetime {
-                return Ok(impl_outgoing_with_incoming_self(&input, &import_path));
+                return Ok(impl_outgoing_with_incoming_self(&input, &ruma_common));
             }
 
             let vis = input.vis;
@@ -136,7 +136,7 @@ pub fn expand_derive_outgoing(input: DeriveInput) -> syn::Result<TokenStream> {
                 #( #input_attrs )*
                 #vis struct #incoming_ident #ty_gen #struct_def
 
-                impl #original_impl_gen #import_path::Outgoing for #original_ident #original_ty_gen {
+                impl #original_impl_gen #ruma_common::Outgoing for #original_ident #original_ty_gen {
                     type Incoming = #incoming_ident #impl_gen;
                 }
             })
@@ -150,12 +150,12 @@ fn filter_input_attrs(attr: &Attribute) -> bool {
     attr.path.is_ident("serde") || attr.path.is_ident("non_exhaustive")
 }
 
-fn impl_outgoing_with_incoming_self(input: &DeriveInput, import_path: &TokenStream) -> TokenStream {
+fn impl_outgoing_with_incoming_self(input: &DeriveInput, ruma_common: &TokenStream) -> TokenStream {
     let ident = &input.ident;
     let (impl_gen, ty_gen, _) = input.generics.split_for_impl();
 
     quote! {
-        impl #impl_gen #import_path::Outgoing for #ident #ty_gen {
+        impl #impl_gen #ruma_common::Outgoing for #ident #ty_gen {
             type Incoming = Self;
         }
     }

ruma-common-macros/src/util.rs

@@ -0,0 +1,15 @@
+use proc_macro2::{Ident, Span, TokenStream};
+use proc_macro_crate::crate_name;
+use quote::quote;
+
+pub fn import_ruma_common() -> TokenStream {
+    if let Ok(possibly_renamed) = crate_name("ruma-common") {
+        let import = Ident::new(&possibly_renamed, Span::call_site());
+        quote! { ::#import }
+    } else if let Ok(possibly_renamed) = crate_name("ruma") {
+        let import = Ident::new(&possibly_renamed, Span::call_site());
+        quote! { ::#import }
+    } else {
+        quote! { ::ruma_common }
+    }
+}

ruma-common/Cargo.toml

@@ -12,7 +12,7 @@ edition = "2018"
 
 [dependencies]
 js_int = { version = "0.1.9", features = ["serde"] }
-ruma-api = { version = "=0.17.0-alpha.1", path = "../ruma-api" }
+ruma-common-macros = { version = "=0.2.0", path = "../ruma-common-macros" }
 ruma-identifiers = { version = "0.17.4", path = "../ruma-identifiers" }
 ruma-serde = { version = "0.2.3", path = "../ruma-serde" }
 serde = { version = "1.0.114", features = ["derive"] }

ruma-common/src/directory.rs

@@ -3,16 +3,16 @@
 use std::fmt;
 
 use js_int::UInt;
-use ruma_api::Outgoing;
 use ruma_identifiers::{RoomAliasId, RoomId};
 use serde::{
     de::{Error, MapAccess, Visitor},
     ser::SerializeStruct,
     Deserialize, Deserializer, Serialize, Serializer,
 };
-
 use serde_json::Value as JsonValue;
 
+use crate::Outgoing;
+
 /// A chunk of a room list response, describing one room.
 ///
 /// To create an instance of this type, first create a `PublicRoomsChunkInit` and convert it via

ruma-common/src/lib.rs

@@ -9,4 +9,29 @@ pub mod push;
 mod raw;
 pub mod thirdparty;
 
+pub use ruma_common_macros::Outgoing;
+
 pub use self::raw::Raw;
+
+/// A type that can be sent to another party that understands the matrix protocol. If any of the
+/// fields of `Self` don't implement serde's `Deserialize`, you can derive this trait to generate a
+/// corresponding 'Incoming' type that supports deserialization. This is useful for things like
+/// ruma_events' `EventResult` type. For more details, see the [derive macro's documentation][doc].
+///
+/// [doc]: derive.Outgoing.html
+// TODO: Better explain how this trait relates to serde's traits
+pub trait Outgoing {
+    /// The 'Incoming' variant of `Self`.
+    type Incoming;
+}
+
+// Hack to allow both ruma-common itself and external crates (or tests) to use procedural macros
+// that expect `ruma_common` to exist in the prelude.
+extern crate self as ruma_common;
+
+/// This module is used to support the generated code from ruma-api-macros.
+/// It is not considered part of ruma-common's public API.
+#[doc(hidden)]
+pub mod exports {
+    pub use serde;
+}

ruma-common/tests/outgoing.rs

@@ -1,4 +1,4 @@
-use ruma_api::Outgoing;
+use ruma_common::Outgoing;
 use ruma_identifiers::UserId;
 
 #[allow(unused)]

ruma-push-gateway-api/src/send_event_notification/v1.rs

@@ -1,8 +1,11 @@
 //! [POST /_matrix/push/v1/notify](https://matrix.org/docs/spec/push_gateway/r0.1.1#post-matrix-push-v1-notify)
 
 use js_int::UInt;
-use ruma_api::{ruma_api, Outgoing};
+use ruma_api::ruma_api;
-use ruma_common::push::{PusherData, Tweak};
+use ruma_common::{
+    push::{PusherData, Tweak},
+    Outgoing,
+};
 use ruma_events::EventType;
 use ruma_identifiers::{EventId, RoomAliasId, RoomId, UserId};
 use serde::{Deserialize, Serialize};