Save two allocations by making MapRPCWriter and `SerializingRPCWrit…

…er` generic over wrapped writer (#1983) Motivation: We currently wrap a base writer into an `RPCWriter` inside the `MapRPCWriter` and `SerializingRPCWriter`. This results in an unnecessary allocation in both cases. In the case of unary requests, this means two extra allocations per requests on the client side. Modifications: Make the `MapRPCWriter` and `SerializingRPCWriter` generic over the base writer, to avoid the extra allocations caused by wrapping them in an `RPCWriter`. Result: Two fewer allocations per unary request on the client side.
grpc · Jul 17, 2024 · 9ae6550 · 9ae6550
1 parent 8af38b1
commit 9ae6550
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Showing 2 changed files with 11 additions and 8 deletions.
diff --git a/Sources/GRPCCore/Streaming/Internal/RPCWriter Map.swift b/Sources/GRPCCore/Streaming/Internal/RPCWriter Map.swift
@@ -16,18 16,18 @@
 
 @available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
 @usableFromInline
-struct MapRPCWriter<Value, Mapped>: RPCWriterProtocol {
 struct MapRPCWriter<Value, Mapped, Base: RPCWriterProtocol<Mapped>>: RPCWriterProtocol {
  @usableFromInline
  typealias Element = Value
 
  @usableFromInline
- let base: RPCWriter<Mapped>
  let base: Base
  @usableFromInline
  let transform: @Sendable (Value) -> Mapped
 
  @inlinable
- init(base: some RPCWriterProtocol<Mapped>, transform: @escaping @Sendable (Value) -> Mapped) {
- self.base = RPCWriter(wrapping: base)
  init(base: Base, transform: @escaping @Sendable (Value) -> Mapped) {
  self.base = base
  self.transform = transform
  }
 

diff --git a/Sources/GRPCCore/Streaming/Internal/RPCWriter Serialize.swift b/Sources/GRPCCore/Streaming/Internal/RPCWriter Serialize.swift
@@ -16,19 16,22 @@
 
 @available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
 @usableFromInline
-struct SerializingRPCWriter<Serializer: MessageSerializer>: RPCWriterProtocol {
 struct SerializingRPCWriter<
  Base: RPCWriterProtocol<[UInt8]>,
  Serializer: MessageSerializer
 >: RPCWriterProtocol {
  @usableFromInline
  typealias Element = Serializer.Message
 
  @usableFromInline
- let base: RPCWriter<[UInt8]>
  let base: Base
  @usableFromInline
  let serializer: Serializer
 
  @inlinable
- init(serializer: Serializer, base: some RPCWriterProtocol<[UInt8]>) {
  init(serializer: Serializer, base: Base) {
  self.serializer = serializer
- self.base = RPCWriter(wrapping: base)
  self.base = base
  }
 
  @inlinable