feat(rust): add sans-IO frame codec and command dispatch table (#2967)

Author: hubcio

core/binary_protocol/src/codec.rs

@@ -75,6 +75,32 @@ pub fn read_u8(buf: &[u8], offset: usize) -> Result<u8, WireError> {
         })
 }
 
+/// Helper to read a `u16` LE from `buf` at `offset`.
+///
+/// # Errors
+/// Returns `WireError::UnexpectedEof` if fewer than 2 bytes remain.
+#[allow(clippy::missing_panics_doc)]
+#[inline]
+pub fn read_u16_le(buf: &[u8], offset: usize) -> Result<u16, WireError> {
+    let end = offset
+        .checked_add(2)
+        .ok_or_else(|| WireError::UnexpectedEof {
+            offset,
+            need: 2,
+            have: buf.len().saturating_sub(offset),
+        })?;
+    let slice = buf
+        .get(offset..end)
+        .ok_or_else(|| WireError::UnexpectedEof {
+            offset,
+            need: 2,
+            have: buf.len().saturating_sub(offset),
+        })?;
+    Ok(u16::from_le_bytes(
+        slice.try_into().expect("slice is exactly 2 bytes"),
+    ))
+}
+
 /// Helper to read a `u32` LE from `buf` at `offset`.
 ///
 /// # Errors
@@ -224,3 +250,35 @@ pub fn read_bytes(buf: &[u8], offset: usize, len: usize) -> Result<&[u8], WireEr
             have: buf.len().saturating_sub(offset),
         })
 }
+
+/// Cap a pre-allocation hint so a bogus wire count cannot cause OOM.
+/// The actual count is validated by the decode loop - this only limits
+/// the upfront allocation.
+#[inline]
+#[must_use]
+pub fn capped_capacity(count: usize, remaining: usize, min_item_size: usize) -> usize {
+    if min_item_size == 0 {
+        return count;
+    }
+    count.min(remaining / min_item_size)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn capped_capacity_limits_allocation() {
+        assert_eq!(capped_capacity(1_000_000, 100, 10), 10);
+        assert_eq!(capped_capacity(5, 100, 10), 5);
+        assert_eq!(capped_capacity(10, 100, 10), 10);
+        assert_eq!(capped_capacity(11, 100, 10), 10);
+        assert_eq!(capped_capacity(0, 100, 10), 0);
+        assert_eq!(capped_capacity(100, 0, 10), 0);
+    }
+
+    #[test]
+    fn capped_capacity_zero_item_size_returns_count() {
+        assert_eq!(capped_capacity(1_000_000, 100, 0), 1_000_000);
+    }
+}

core/binary_protocol/src/codes.rs

@@ -87,58 +87,14 @@ pub const DELETE_CONSUMER_GROUP_CODE: u32 = 603;
 pub const JOIN_CONSUMER_GROUP_CODE: u32 = 604;
 pub const LEAVE_CONSUMER_GROUP_CODE: u32 = 605;
 
+/// Lookup the human-readable name for a command code.
+///
 /// # Errors
 /// Returns `WireError::UnknownCommand` if the code is not recognized.
 pub const fn command_name(code: u32) -> Result<&'static str, WireError> {
-    match code {
-        PING_CODE => Ok("ping"),
-        GET_STATS_CODE => Ok("stats"),
-        GET_SNAPSHOT_FILE_CODE => Ok("snapshot"),
-        GET_CLUSTER_METADATA_CODE => Ok("cluster.metadata"),
-        GET_ME_CODE => Ok("me"),
-        GET_CLIENT_CODE => Ok("client.get"),
-        GET_CLIENTS_CODE => Ok("client.list"),
-        GET_USER_CODE => Ok("user.get"),
-        GET_USERS_CODE => Ok("user.list"),
-        CREATE_USER_CODE => Ok("user.create"),
-        DELETE_USER_CODE => Ok("user.delete"),
-        UPDATE_USER_CODE => Ok("user.update"),
-        UPDATE_PERMISSIONS_CODE => Ok("user.permissions"),
-        CHANGE_PASSWORD_CODE => Ok("user.password"),
-        LOGIN_USER_CODE => Ok("user.login"),
-        LOGOUT_USER_CODE => Ok("user.logout"),
-        GET_PERSONAL_ACCESS_TOKENS_CODE => Ok("personal_access_token.list"),
-        CREATE_PERSONAL_ACCESS_TOKEN_CODE => Ok("personal_access_token.create"),
-        DELETE_PERSONAL_ACCESS_TOKEN_CODE => Ok("personal_access_token.delete"),
-        LOGIN_WITH_PERSONAL_ACCESS_TOKEN_CODE => Ok("personal_access_token.login"),
-        POLL_MESSAGES_CODE => Ok("message.poll"),
-        SEND_MESSAGES_CODE => Ok("message.send"),
-        FLUSH_UNSAVED_BUFFER_CODE => Ok("message.flush_unsaved_buffer"),
-        GET_CONSUMER_OFFSET_CODE => Ok("consumer_offset.get"),
-        STORE_CONSUMER_OFFSET_CODE => Ok("consumer_offset.store"),
-        DELETE_CONSUMER_OFFSET_CODE => Ok("consumer_offset.delete"),
-        GET_STREAM_CODE => Ok("stream.get"),
-        GET_STREAMS_CODE => Ok("stream.list"),
-        CREATE_STREAM_CODE => Ok("stream.create"),
-        DELETE_STREAM_CODE => Ok("stream.delete"),
-        UPDATE_STREAM_CODE => Ok("stream.update"),
-        PURGE_STREAM_CODE => Ok("stream.purge"),
-        GET_TOPIC_CODE => Ok("topic.get"),
-        GET_TOPICS_CODE => Ok("topic.list"),
-        CREATE_TOPIC_CODE => Ok("topic.create"),
-        DELETE_TOPIC_CODE => Ok("topic.delete"),
-        UPDATE_TOPIC_CODE => Ok("topic.update"),
-        PURGE_TOPIC_CODE => Ok("topic.purge"),
-        CREATE_PARTITIONS_CODE => Ok("partition.create"),
-        DELETE_PARTITIONS_CODE => Ok("partition.delete"),
-        DELETE_SEGMENTS_CODE => Ok("segment.delete"),
-        GET_CONSUMER_GROUP_CODE => Ok("consumer_group.get"),
-        GET_CONSUMER_GROUPS_CODE => Ok("consumer_group.list"),
-        CREATE_CONSUMER_GROUP_CODE => Ok("consumer_group.create"),
-        DELETE_CONSUMER_GROUP_CODE => Ok("consumer_group.delete"),
-        JOIN_CONSUMER_GROUP_CODE => Ok("consumer_group.join"),
-        LEAVE_CONSUMER_GROUP_CODE => Ok("consumer_group.leave"),
-        _ => Err(WireError::UnknownCommand(code)),
+    match crate::dispatch::lookup_command(code) {
+        Some(meta) => Ok(meta.name),
+        None => Err(WireError::UnknownCommand(code)),
     }
 }
 

core/binary_protocol/src/consensus/operation.rs

@@ -95,64 +95,48 @@ impl Operation {
     }
 
     /// Bidirectional mapping: `Operation` -> client command code.
+    ///
+    /// Delegates to the dispatch table as the single source of truth.
     #[must_use]
     pub const fn to_command_code(&self) -> Option<u32> {
-        use crate::codes;
         match self {
             Self::Reserved => None,
-            Self::CreateStream => Some(codes::CREATE_STREAM_CODE),
-            Self::UpdateStream => Some(codes::UPDATE_STREAM_CODE),
-            Self::DeleteStream => Some(codes::DELETE_STREAM_CODE),
-            Self::PurgeStream => Some(codes::PURGE_STREAM_CODE),
-            Self::CreateTopic => Some(codes::CREATE_TOPIC_CODE),
-            Self::UpdateTopic => Some(codes::UPDATE_TOPIC_CODE),
-            Self::DeleteTopic => Some(codes::DELETE_TOPIC_CODE),
-            Self::PurgeTopic => Some(codes::PURGE_TOPIC_CODE),
-            Self::CreatePartitions => Some(codes::CREATE_PARTITIONS_CODE),
-            Self::DeletePartitions => Some(codes::DELETE_PARTITIONS_CODE),
-            Self::DeleteSegments => Some(codes::DELETE_SEGMENTS_CODE),
-            Self::CreateConsumerGroup => Some(codes::CREATE_CONSUMER_GROUP_CODE),
-            Self::DeleteConsumerGroup => Some(codes::DELETE_CONSUMER_GROUP_CODE),
-            Self::CreateUser => Some(codes::CREATE_USER_CODE),
-            Self::UpdateUser => Some(codes::UPDATE_USER_CODE),
-            Self::DeleteUser => Some(codes::DELETE_USER_CODE),
-            Self::ChangePassword => Some(codes::CHANGE_PASSWORD_CODE),
-            Self::UpdatePermissions => Some(codes::UPDATE_PERMISSIONS_CODE),
-            Self::CreatePersonalAccessToken => Some(codes::CREATE_PERSONAL_ACCESS_TOKEN_CODE),
-            Self::DeletePersonalAccessToken => Some(codes::DELETE_PERSONAL_ACCESS_TOKEN_CODE),
-            Self::SendMessages => Some(codes::SEND_MESSAGES_CODE),
-            Self::StoreConsumerOffset => Some(codes::STORE_CONSUMER_OFFSET_CODE),
+            Self::CreateStream
+            | Self::UpdateStream
+            | Self::DeleteStream
+            | Self::PurgeStream
+            | Self::CreateTopic
+            | Self::UpdateTopic
+            | Self::DeleteTopic
+            | Self::PurgeTopic
+            | Self::CreatePartitions
+            | Self::DeletePartitions
+            | Self::DeleteSegments
+            | Self::CreateConsumerGroup
+            | Self::DeleteConsumerGroup
+            | Self::CreateUser
+            | Self::UpdateUser
+            | Self::DeleteUser
+            | Self::ChangePassword
+            | Self::UpdatePermissions
+            | Self::CreatePersonalAccessToken
+            | Self::DeletePersonalAccessToken
+            | Self::SendMessages
+            | Self::StoreConsumerOffset => match crate::dispatch::lookup_by_operation(*self) {
+                Some(meta) => Some(meta.code),
+                None => None,
+            },
         }
     }
 
     /// Bidirectional mapping: client command code -> `Operation`.
+    ///
+    /// Delegates to the dispatch table as the single source of truth.
     #[must_use]
     pub const fn from_command_code(code: u32) -> Option<Self> {
-        use crate::codes;
-        match code {
-            codes::CREATE_STREAM_CODE => Some(Self::CreateStream),
-            codes::UPDATE_STREAM_CODE => Some(Self::UpdateStream),
-            codes::DELETE_STREAM_CODE => Some(Self::DeleteStream),
-            codes::PURGE_STREAM_CODE => Some(Self::PurgeStream),
-            codes::CREATE_TOPIC_CODE => Some(Self::CreateTopic),
-            codes::UPDATE_TOPIC_CODE => Some(Self::UpdateTopic),
-            codes::DELETE_TOPIC_CODE => Some(Self::DeleteTopic),
-            codes::PURGE_TOPIC_CODE => Some(Self::PurgeTopic),
-            codes::CREATE_PARTITIONS_CODE => Some(Self::CreatePartitions),
-            codes::DELETE_PARTITIONS_CODE => Some(Self::DeletePartitions),
-            codes::DELETE_SEGMENTS_CODE => Some(Self::DeleteSegments),
-            codes::CREATE_CONSUMER_GROUP_CODE => Some(Self::CreateConsumerGroup),
-            codes::DELETE_CONSUMER_GROUP_CODE => Some(Self::DeleteConsumerGroup),
-            codes::CREATE_USER_CODE => Some(Self::CreateUser),
-            codes::UPDATE_USER_CODE => Some(Self::UpdateUser),
-            codes::DELETE_USER_CODE => Some(Self::DeleteUser),
-            codes::CHANGE_PASSWORD_CODE => Some(Self::ChangePassword),
-            codes::UPDATE_PERMISSIONS_CODE => Some(Self::UpdatePermissions),
-            codes::CREATE_PERSONAL_ACCESS_TOKEN_CODE => Some(Self::CreatePersonalAccessToken),
-            codes::DELETE_PERSONAL_ACCESS_TOKEN_CODE => Some(Self::DeletePersonalAccessToken),
-            codes::SEND_MESSAGES_CODE => Some(Self::SendMessages),
-            codes::STORE_CONSUMER_OFFSET_CODE => Some(Self::StoreConsumerOffset),
-            _ => None,
+        match crate::dispatch::lookup_command(code) {
+            Some(meta) => meta.operation,
+            None => None,
         }
     }
 }
@@ -204,10 +188,11 @@ mod tests {
 
     #[test]
     fn read_only_commands_have_no_operation() {
-        assert!(Operation::from_command_code(crate::PING_CODE).is_none());
-        assert!(Operation::from_command_code(crate::GET_STATS_CODE).is_none());
-        assert!(Operation::from_command_code(crate::GET_STREAM_CODE).is_none());
-        assert!(Operation::from_command_code(crate::POLL_MESSAGES_CODE).is_none());
+        use crate::codes::{GET_STATS_CODE, GET_STREAM_CODE, PING_CODE, POLL_MESSAGES_CODE};
+        assert!(Operation::from_command_code(PING_CODE).is_none());
+        assert!(Operation::from_command_code(GET_STATS_CODE).is_none());
+        assert!(Operation::from_command_code(GET_STREAM_CODE).is_none());
+        assert!(Operation::from_command_code(POLL_MESSAGES_CODE).is_none());
     }
 
     #[test]