Replace impl_enum with strum::{EnumString,Display}

Replace the impl_enum! macro, which automatically derives instances of
std::fmt::Display and std::string::FromStr, with derive macros from the
strum crate (Display and EnumString resp.).

Closes #90.

Cargo.toml

@@ -20,6 +20,7 @@ ruma-identifiers = "0.16.1"
 ruma-serde = "0.2.1"
 serde = { version = "1.0.110", features = ["derive"] }
 serde_json = { version = "1.0.53", features = ["raw_value"] }
+strum = { version = "0.18.0", features = ["derive"] }
 
 [dev-dependencies]
 maplit = "1.0.2"

src/call.rs

@@ -3,6 +3,7 @@
 //! This module also contains types shared by events in its child namespaces.
 
 use serde::{Deserialize, Serialize};
+use strum::{Display, EnumString};
 
 pub mod answer;
 pub mod candidates;
@@ -21,9 +22,10 @@ pub struct SessionDescription {
 }
 
 /// The type of VoIP session description.
-#[derive(Clone, Copy, Debug, PartialEq, Deserialize, Serialize)]
+#[derive(Clone, Copy, Debug, Display, EnumString, PartialEq, Deserialize, Serialize)]
 #[non_exhaustive]
 #[serde(rename_all = "lowercase")]
+#[strum(serialize_all = "lowercase")]
 pub enum SessionDescriptionType {
     /// An answer.
     Answer,
@@ -31,10 +33,3 @@ pub enum SessionDescriptionType {
     /// An offer.
     Offer,
 }
-
-impl_enum! {
-    SessionDescriptionType {
-        Answer => "answer",
-        Offer => "offer",
-    }
-}

src/call/hangup.rs

@@ -3,6 +3,7 @@
 use js_int::UInt;
 use ruma_events_macros::ruma_event;
 use serde::{Deserialize, Serialize};
+use strum::{Display, EnumString};
 
 ruma_event! {
     /// Sent by either party to signal their termination of the call. This can be sent either once
@@ -29,8 +30,9 @@ ruma_event! {
 /// This should not be provided when the user naturally ends or rejects the call. When there was an
 /// error in the call negotiation, this should be `ice_failed` for when ICE negotiation fails or
 /// `invite_timeout` for when the other party did not answer in time.
-#[derive(Clone, Copy, Debug, PartialEq, Deserialize, Serialize)]
+#[derive(Clone, Copy, Debug, Display, EnumString, PartialEq, Deserialize, Serialize)]
 #[serde(rename_all = "snake_case")]
+#[strum(serialize_all = "snake_case")]
 pub enum Reason {
     /// ICE negotiation failure.
     IceFailed,
@@ -38,10 +40,3 @@ pub enum Reason {
     /// Party did not answer in time.
     InviteTimeout,
 }
-
-impl_enum! {
-    Reason {
-        IceFailed => "ice_failed",
-        InviteTimeout => "invite_timeout",
-    }
-}

src/key/verification.rs

@@ -3,6 +3,7 @@
 //! This module also contains types shared by events in its child namespaces.
 
 use serde::{Deserialize, Serialize};
+use strum::{Display, EnumString};
 
 pub mod accept;
 pub mod cancel;
@@ -12,76 +13,51 @@ pub mod request;
 pub mod start;
 
 /// A hash algorithm.
-#[derive(Clone, Copy, Debug, Serialize, PartialEq, Deserialize)]
+#[derive(Clone, Copy, Debug, Display, EnumString, Serialize, PartialEq, Deserialize)]
 pub enum HashAlgorithm {
     /// The SHA256 hash algorithm.
     #[serde(rename = "sha256")]
+    #[strum(serialize = "sha256")]
     Sha256,
 }
 
-impl_enum! {
-    HashAlgorithm {
-        Sha256 => "sha256",
-    }
-}
-
 /// A key agreement protocol.
-#[derive(Clone, Copy, Debug, Serialize, PartialEq, Deserialize)]
+#[derive(Clone, Copy, Debug, Display, EnumString, Serialize, PartialEq, Deserialize)]
 pub enum KeyAgreementProtocol {
     /// The [Curve25519](https://cr.yp.to/ecdh.html) key agreement protocol.
     #[serde(rename = "curve25519")]
+    #[strum(serialize = "curve25519")]
     Curve25519,
 }
 
-impl_enum! {
-    KeyAgreementProtocol {
-        Curve25519 => "curve25519",
-    }
-}
-
 /// A message authentication code algorithm.
-#[derive(Clone, Copy, Debug, Serialize, PartialEq, Deserialize)]
+#[derive(Clone, Copy, Debug, Display, EnumString, Serialize, PartialEq, Deserialize)]
 pub enum MessageAuthenticationCode {
     /// The HKDF-HMAC-SHA256 MAC.
     #[serde(rename = "hkdf-hmac-sha256")]
+    #[strum(serialize = "hkdf-hmac-sha256")]
     HkdfHmacSha256,
 }
 
-impl_enum! {
-    MessageAuthenticationCode {
-        HkdfHmacSha256 => "hkdf-hmac-sha256",
-    }
-}
-
 /// A Short Authentication String method.
-#[derive(Clone, Copy, Debug, Serialize, PartialEq, Deserialize)]
+#[derive(Clone, Copy, Debug, Display, EnumString, Serialize, PartialEq, Deserialize)]
 pub enum ShortAuthenticationString {
     /// The decimal method.
     #[serde(rename = "decimal")]
+    #[strum(serialize = "decimal")]
     Decimal,
 
     /// The emoji method.
     #[serde(rename = "emoji")]
+    #[strum(serialize = "emoji")]
     Emoji,
 }
 
-impl_enum! {
-    ShortAuthenticationString {
-        Decimal => "decimal",
-        Emoji => "emoji",
-    }
-}
-
 /// A Short Authentication String (SAS) verification method.
-#[derive(Clone, Copy, Debug, PartialEq, Deserialize, Serialize)]
+#[derive(Clone, Copy, Debug, Display, EnumString, PartialEq, Deserialize, Serialize)]
 pub enum VerificationMethod {
     /// The *m.sas.v1* verification method.
     #[serde(rename = "m.sas.v1")]
+    #[strum(serialize = "m.sas.v1")]
     MSasV1,
 }
-
-impl_enum! {
-    VerificationMethod {
-        MSasV1 => "m.sas.v1",
-    }
-}

src/macros.rs

@@ -1,28 +1,3 @@
-macro_rules! impl_enum {
-    ($name:ident { $($variant:ident => $s:expr,)+ }) => {
-        impl ::std::fmt::Display for $name {
-            fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> Result<(), ::std::fmt::Error> {
-                let variant = match *self {
-                    $($name::$variant => $s,)*
-                };
-
-                write!(f, "{}", variant)
-            }
-        }
-
-        impl ::std::str::FromStr for $name {
-            type Err = $crate::FromStrError;
-
-            fn from_str(s: &str) -> Result<Self, Self::Err> {
-                match s {
-                    $($s => Ok($name::$variant),)*
-                    _ => Err($crate::FromStrError),
-                }
-            }
-        }
-    }
-}
-
 macro_rules! impl_event {
     ($name:ident, $content_name:ident, $event_type:path) => {
         impl crate::Event for $name {

src/presence.rs

@@ -4,6 +4,7 @@ use js_int::UInt;
 use ruma_events_macros::ruma_event;
 use ruma_identifiers::UserId;
 use serde::{Deserialize, Serialize};
+use strum::{Display, EnumString};
 
 ruma_event! {
     /// Informs the client of a user's presence state change.
@@ -42,29 +43,24 @@ ruma_event! {
 }
 
 /// A description of a user's connectivity and availability for chat.
-#[derive(Clone, Copy, Debug, PartialEq, Deserialize, Serialize)]
+#[derive(Clone, Copy, Debug, Display, EnumString, PartialEq, Deserialize, Serialize)]
 pub enum PresenceState {
     /// Disconnected from the service.
     #[serde(rename = "offline")]
+    #[strum(serialize = "offline")]
     Offline,
 
     /// Connected to the service.
     #[serde(rename = "online")]
+    #[strum(serialize = "online")]
     Online,
 
     /// Connected to the service but not available for chat.
     #[serde(rename = "unavailable")]
+    #[strum(serialize = "unavailable")]
     Unavailable,
 }
 
-impl_enum! {
-    PresenceState {
-        Offline => "offline",
-        Online => "online",
-        Unavailable => "unavailable",
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use std::convert::TryFrom;

src/room/guest_access.rs

@@ -2,6 +2,7 @@
 
 use ruma_events_macros::ruma_event;
 use serde::{Deserialize, Serialize};
+use strum::{Display, EnumString};
 
 ruma_event! {
     /// Controls whether guest users are allowed to join rooms.
@@ -19,9 +20,10 @@ ruma_event! {
 }
 
 /// A policy for guest user access to a room.
-#[derive(Clone, Copy, Debug, PartialEq, Deserialize, Serialize)]
+#[derive(Clone, Copy, Debug, Display, EnumString, PartialEq, Deserialize, Serialize)]
 #[non_exhaustive]
 #[serde(rename_all = "snake_case")]
+#[strum(serialize_all = "snake_case")]
 pub enum GuestAccess {
     /// Guests are allowed to join the room.
     CanJoin,
@@ -29,10 +31,3 @@ pub enum GuestAccess {
     /// Guests are not allowed to join the room.
     Forbidden,
 }
-
-impl_enum! {
-    GuestAccess {
-        CanJoin => "can_join",
-        Forbidden => "forbidden",
-    }
-}

src/room/history_visibility.rs

@@ -2,6 +2,7 @@
 
 use ruma_events_macros::ruma_event;
 use serde::{Deserialize, Serialize};
+use strum::{Display, EnumString};
 
 ruma_event! {
     /// This event controls whether a member of a room can see the events that happened in a room
@@ -17,8 +18,9 @@ ruma_event! {
 }
 
 /// Who can see a room's history.
-#[derive(Clone, Copy, Debug, PartialEq, Deserialize, Serialize)]
+#[derive(Clone, Copy, Debug, Display, EnumString, PartialEq, Deserialize, Serialize)]
 #[serde(rename_all = "snake_case")]
+#[strum(serialize_all = "snake_case")]
 pub enum HistoryVisibility {
     /// Previous events are accessible to newly joined members from the point they were invited
     /// onwards. Events stop being accessible when the member's state changes to something other
@@ -38,12 +40,3 @@ pub enum HistoryVisibility {
     /// participating homeserver with anyone, regardless of whether they have ever joined the room.
     WorldReadable,
 }
-
-impl_enum! {
-    HistoryVisibility {
-        Invited => "invited",
-        Joined => "joined",
-        Shared => "shared",
-        WorldReadable => "world_readable",
-    }
-}

src/room/join_rules.rs

@@ -2,6 +2,7 @@
 
 use ruma_events_macros::ruma_event;
 use serde::{Deserialize, Serialize};
+use strum::{Display, EnumString};
 
 ruma_event! {
     /// Describes how users are allowed to join the room.
@@ -16,8 +17,9 @@ ruma_event! {
 }
 
 /// The rule used for users wishing to join this room.
-#[derive(Clone, Copy, Debug, PartialEq, Deserialize, Serialize)]
+#[derive(Clone, Copy, Debug, Display, EnumString, PartialEq, Deserialize, Serialize)]
 #[serde(rename_all = "lowercase")]
+#[strum(serialize_all = "lowercase")]
 pub enum JoinRule {
     /// A user who wishes to join the room must first receive an invite to the room from someone
     /// already inside of the room.
@@ -32,12 +34,3 @@ pub enum JoinRule {
     /// Anyone can join the room without any prior action.
     Public,
 }
-
-impl_enum! {
-    JoinRule {
-        Invite => "invite",
-        Knock => "knock",
-        Private => "private",
-        Public => "public",
-    }
-}

src/room/member.rs

@@ -5,6 +5,7 @@ use std::collections::BTreeMap;
 use ruma_events_macros::ruma_event;
 use ruma_identifiers::UserId;
 use serde::{Deserialize, Serialize};
+use strum::{Display, EnumString};
 
 ruma_event! {
     /// The current membership state of a user in the room.
@@ -63,8 +64,9 @@ ruma_event! {
 }
 
 /// The membership state of a user.
-#[derive(Clone, Copy, Debug, PartialEq, Deserialize, Serialize)]
+#[derive(Clone, Copy, Debug, Display, EnumString, PartialEq, Deserialize, Serialize)]
 #[serde(rename_all = "lowercase")]
+#[strum(serialize_all = "lowercase")]
 pub enum MembershipState {
     /// The user is banned.
     Ban,
@@ -82,16 +84,6 @@ pub enum MembershipState {
     Leave,
 }
 
-impl_enum! {
-    MembershipState {
-        Ban => "ban",
-        Invite => "invite",
-        Join => "join",
-        Knock => "knock",
-        Leave => "leave",
-    }
-}
-
 /// Information about a third party invitation.
 #[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct ThirdPartyInvite {

src/room/message/feedback.rs

@@ -3,6 +3,7 @@
 use ruma_events_macros::ruma_event;
 use ruma_identifiers::EventId;
 use serde::{Deserialize, Serialize};
+use strum::{Display, EnumString};
 
 ruma_event! {
     /// An acknowledgement of a message.
@@ -24,8 +25,9 @@ ruma_event! {
 }
 
 /// A type of feedback.
-#[derive(Clone, Copy, Debug, PartialEq, Deserialize, Serialize)]
+#[derive(Clone, Copy, Debug, Display, EnumString, PartialEq, Deserialize, Serialize)]
 #[serde(rename_all = "lowercase")]
+#[strum(serialize_all = "lowercase")]
 pub enum FeedbackType {
     /// Sent when a message is received.
     Delivered,
@@ -33,10 +35,3 @@ pub enum FeedbackType {
     /// Sent when a message has been observed by the end user.
     Read,
 }
-
-impl_enum! {
-    FeedbackType {
-        Delivered => "delivered",
-        Read => "read",
-    }
-}

src/room_key_request.rs

@@ -3,6 +3,7 @@
 use ruma_events_macros::ruma_event;
 use ruma_identifiers::{DeviceId, RoomId};
 use serde::{Deserialize, Serialize};
+use strum::{Display, EnumString};
 
 use super::Algorithm;
 
@@ -35,24 +36,19 @@ ruma_event! {
 }
 
 /// A new key request or a cancellation of a previous request.
-#[derive(Clone, Copy, Debug, PartialEq, Deserialize, Serialize)]
+#[derive(Clone, Copy, Debug, Display, EnumString, PartialEq, Deserialize, Serialize)]
 pub enum Action {
     /// Request a key.
     #[serde(rename = "request")]
+    #[strum(serialize = "request")]
     Request,
 
     /// Cancel a request for a key.
     #[serde(rename = "request_cancellation")]
+    #[strum(serialize = "request_cancellation")]
     CancelRequest,
 }
 
-impl_enum! {
-    Action {
-        Request => "request",
-        CancelRequest => "cancel_request",
-    }
-}
-
 /// Information about a requested key.
 #[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct RequestedKeyInfo {