Introduce internal bitflags! macro with serde implementation (#1684)

The macro forwards the generation to the `bitflags::bitflags!` macro and
implements the default (de)serialization for Discord's bitmask values.

If a different serde implementation is required then the `bitflags::bitflags!`
macro must be used directly. See `Permissions`.

Cargo.toml

@@ -16,7 +16,7 @@ include = ["src/**/*", "LICENSE.md", "README.md", "CHANGELOG.md", "build.rs"]
 members = ["examples/*"]
 
 [dependencies]
-bitflags = "1.1"
+bitflags = "1.3"
 serde_json = "1.0.75"
 async-trait = "0.1.9"
 

src/internal/macros.rs

@@ -97,24 +97,52 @@ macro_rules! enum_number {
     }
 }
 
-macro_rules! impl_bitflags_serde {
-    ($name:ident: $type:tt) => {
-        impl<'de> serde::de::Deserialize<'de> for $name {
-            fn deserialize<D>(deserializer: D) -> std::result::Result<Self, D::Error>
-            where
-                D: serde::de::Deserializer<'de>,
-            {
-                Ok(Self::from_bits_truncate(<$type>::deserialize(deserializer)?))
+/// The macro forwards the generation to the `bitflags::bitflags!` macro and implements
+/// the default (de)serialization for Discord's bitmask values.
+///
+/// The flags are created with `T::from_bits_truncate` for the deserialized integer value.
+///
+/// Use the `bitflags::bitflags! macro directly if a different serde implementation is required.
+macro_rules! bitflags {
+    (
+        $(#[$outer:meta])*
+        $vis:vis struct $BitFlags:ident: $T:ty {
+            $(
+                $(#[$inner:ident $($args:tt)*])*
+                const $Flag:ident = $value:expr;
+            )*
+        }
+
+        $($t:tt)*
+    ) => {
+        bitflags::bitflags! {
+            $(#[$outer])*
+            $vis struct $BitFlags: $T {
+                $(
+                    $(#[$inner $($args)*])*
+                    const $Flag = $value;
+                )*
             }
         }
 
-        impl serde::ser::Serialize for $name {
-            fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
-            where
-                S: serde::ser::Serializer,
-            {
+        bitflags!(__impl_serde $BitFlags: $T);
+
+        bitflags! {
+            $($t)*
+        }
+    };
+    (__impl_serde $BitFlags:ident: $T:tt) => {
+        impl<'de> serde::de::Deserialize<'de> for $BitFlags {
+            fn deserialize<D: serde::de::Deserializer<'de>>(deserializer: D) -> std::result::Result<Self, D::Error> {
+                Ok(Self::from_bits_truncate(<$T>::deserialize(deserializer)?))
+            }
+        }
+
+        impl serde::ser::Serialize for $BitFlags {
+            fn serialize<S: serde::ser::Serializer>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error> {
                 self.bits().serialize(serializer)
             }
         }
     };
+    () => {};
 }

src/model/channel/message.rs

@@ -5,7 +5,6 @@ use std::fmt::Display;
 #[cfg(all(feature = "cache", feature = "model"))]
 use std::fmt::Write;
 
-use bitflags::bitflags;
 use chrono::{DateTime, Utc};
 #[cfg(feature = "simd-json")]
 use simd_json::ValueAccess;
@@ -1253,8 +1252,6 @@ bitflags! {
     }
 }
 
-impl_bitflags_serde!(MessageFlags: u64);
-
 #[cfg(feature = "model")]
 impl MessageId {
     /// Returns a link referencing this message. When clicked, users will jump to the message.

src/model/gateway.rs

@@ -1,6 +1,5 @@
 //! Models pertaining to the gateway.
 
-use bitflags::bitflags;
 use url::Url;
 
 use super::prelude::*;
@@ -317,8 +316,6 @@ bitflags! {
     }
 }
 
-impl_bitflags_serde!(ActivityFlags: u64);
-
 /// Information about an activity's party.
 #[derive(Clone, Debug, Deserialize, Serialize)]
 #[non_exhaustive]
@@ -670,8 +667,6 @@ bitflags! {
     }
 }
 
-impl_bitflags_serde!(GatewayIntents: u64);
-
 #[cfg(feature = "model")]
 impl GatewayIntents {
     /// Gets all of the intents that don't are considered privileged by Discord.

src/model/guild/member.rs

@@ -4,7 +4,6 @@ use std::borrow::Cow;
 use std::cmp::Reverse;
 use std::fmt::{Display, Formatter, Result as FmtResult};
 
-use bitflags::bitflags;
 use chrono::{DateTime, Utc};
 
 #[cfg(feature = "model")]
@@ -725,5 +724,3 @@ bitflags! {
         const NOTIFICATIONS = 1 << 0;
     }
 }
-
-impl_bitflags_serde!(ThreadMemberFlags: u64);

src/model/guild/system_channel.rs

@@ -1,5 +1,3 @@
-use bitflags::bitflags;
-
 bitflags! {
     /// Describes a system channel flags.
     #[derive(Default)]
@@ -14,5 +12,3 @@ bitflags! {
         const SUPPRESS_JOIN_NOTIFICATION_REPLIES = 1 << 3;
     }
 }
-
-impl_bitflags_serde!(SystemChannelFlags: u64);

src/model/interactions/mod.rs

@@ -6,7 +6,6 @@ pub mod ping;
 
 use application_command::ApplicationCommandInteraction;
 use autocomplete::AutocompleteInteraction;
-use bitflags::bitflags;
 use message_component::MessageComponentInteraction;
 use modal::ModalSubmitInteraction;
 use ping::PingInteraction;
@@ -210,8 +209,6 @@ bitflags! {
     }
 }
 
-impl_bitflags_serde!(InteractionApplicationCommandCallbackDataFlags: u64);
-
 /// Sent when a [`Message`] is a response to an [`Interaction`].
 ///
 /// [`Message`]: crate::model::channel::Message

src/model/permissions.rs

@@ -44,7 +44,6 @@
 #[cfg(feature = "model")]
 use std::fmt::{Display, Formatter, Result as FmtResult};
 
-use bitflags::bitflags;
 use serde::de::{Deserialize, Deserializer};
 use serde::ser::{Serialize, Serializer};
 
@@ -220,7 +219,7 @@ pub const PRESET_VOICE: Permissions = Permissions {
     bits: Permissions::CONNECT.bits | Permissions::SPEAK.bits | Permissions::USE_VAD.bits,
 };
 
-bitflags! {
+bitflags::bitflags! {
     /// A set of permissions that can be assigned to [`User`]s and [`Role`]s via
     /// [`PermissionOverwrite`]s, roles globally in a [`Guild`], and to
     /// [`GuildChannel`]s.

src/model/user.rs

@@ -4,7 +4,6 @@ use std::fmt;
 #[cfg(feature = "model")]
 use std::fmt::Write;
 
-use bitflags::bitflags;
 #[cfg(feature = "model")]
 use futures::future::{BoxFuture, FutureExt};
 use serde::{Deserialize, Serialize};
@@ -693,8 +692,6 @@ bitflags! {
     }
 }
 
-impl_bitflags_serde!(UserPublicFlags: u32);
-
 impl Default for User {
     /// Initializes a [`User`] with default values. Setting the following:
     /// - **id** to `UserId(210)`