1 // Copyright 2019 TiKV Project Authors. Licensed under Apache-2.0. 2 3 use crate::buf::GrpcSlice; 4 use crate::call::MessageReader; 5 use crate::error::Result; 6 7 pub type DeserializeFn<T> = fn(MessageReader) -> Result<T>; 8 pub type SerializeFn<T> = fn(&T, &mut GrpcSlice); 9 10 /// Defines how to serialize and deserialize between the specialized type and byte slice. 11 pub struct Marshaller<T> { 12 // Use function pointer here to simplify the signature. 13 // Compiler will probably inline the function so performance 14 // impact can be omitted. 15 // 16 // Using trait will require a trait object or generic, which will 17 // either have performance impact or make signature complicated. 18 // 19 // const function is not stable yet (rust-lang/rust#24111), hence 20 // make all fields public. 21 /// The serialize function. 22 pub ser: SerializeFn<T>, 23 24 /// The deserialize function. 25 pub de: DeserializeFn<T>, 26 } 27 28 #[cfg(feature = "protobuf-codec")] 29 pub mod pb_codec { 30 use protobuf::{CodedInputStream, CodedOutputStream, Message}; 31 32 use super::MessageReader; 33 use crate::buf::GrpcSlice; 34 use crate::error::Result; 35 36 #[inline] ser<T: Message>(t: &T, buf: &mut GrpcSlice)37 pub fn ser<T: Message>(t: &T, buf: &mut GrpcSlice) { 38 let cap = t.compute_size(); 39 unsafe { 40 let bytes = buf.realloc(cap as usize); 41 let raw_bytes = &mut *(bytes as *mut [std::mem::MaybeUninit<u8>] as *mut [u8]); 42 let mut s = CodedOutputStream::bytes(raw_bytes); 43 t.write_to_with_cached_sizes(&mut s).unwrap(); 44 } 45 } 46 47 #[inline] de<T: Message>(mut reader: MessageReader) -> Result<T>48 pub fn de<T: Message>(mut reader: MessageReader) -> Result<T> { 49 let mut s = CodedInputStream::from_buffered_reader(&mut reader); 50 let mut m = T::new(); 51 m.merge_from(&mut s)?; 52 Ok(m) 53 } 54 } 55 56 #[cfg(feature = "prost-codec")] 57 pub mod pr_codec { 58 use prost::Message; 59 60 use super::MessageReader; 61 use crate::buf::GrpcSlice; 62 use crate::error::Result; 63 64 #[inline] ser<M: Message>(msg: &M, buf: &mut GrpcSlice)65 pub fn ser<M: Message>(msg: &M, buf: &mut GrpcSlice) { 66 let size = msg.encoded_len(); 67 unsafe { 68 let bytes = buf.realloc(size); 69 let mut b = &mut *(bytes as *mut [std::mem::MaybeUninit<u8>] as *mut [u8]); 70 msg.encode(&mut b) 71 .expect("Writing message to buffer failed"); 72 debug_assert!(b.is_empty()); 73 } 74 } 75 76 #[inline] de<M: Message + Default>(mut reader: MessageReader) -> Result<M>77 pub fn de<M: Message + Default>(mut reader: MessageReader) -> Result<M> { 78 use bytes::buf::Buf; 79 reader.advance(0); 80 M::decode(reader).map_err(Into::into) 81 } 82 } 83