introduce specialization for API v1

Signed-off-by: iosmanthus <myosmanthustree@gmail.com>

Author: iosmanthus

src/lib.rs

@@ -90,6 +90,7 @@
 //! # })}
 //! ```
 
+#![feature(specialization)]
 #[macro_use]
 pub mod request;
 #[macro_use]

src/pd/client.rs

@@ -1,23 +1,28 @@
 // Copyright 2018 TiKV Project Authors. Licensed under Apache-2.0.
 
-use crate::{
-    compat::stream_fn,
-    kv::codec,
-    pd::{retry::RetryClientTrait, RetryClient},
-    region::{RegionId, RegionVerId, RegionWithLeader},
-    region_cache::RegionCache,
-    store::RegionStore,
-    BoundRange, Config, Key, Result, SecurityManager, Timestamp,
-};
+use std::{collections::HashMap, sync::Arc, thread};
+use std::marker::PhantomData;
+
 use async_trait::async_trait;
 use futures::{prelude::*, stream::BoxStream};
 use grpcio::{EnvBuilder, Environment};
 use slog::Logger;
-use std::{collections::HashMap, sync::Arc, thread};
+use tokio::sync::RwLock;
+
 use tikv_client_pd::Cluster;
 use tikv_client_proto::{kvrpcpb, metapb};
 use tikv_client_store::{KvClient, KvConnect, TikvConnect};
-use tokio::sync::RwLock;
+
+use crate::{
+    BoundRange,
+    compat::stream_fn,
+    Config,
+    Key,
+    kv::codec,
+    pd::{retry::RetryClientTrait, RetryClient},
+    region::{RegionId, RegionVerId, RegionWithLeader}, region_cache::RegionCache, Result, SecurityManager, store::RegionStore, Timestamp,
+};
+use crate::request::request_codec::RequestCodec;
 
 const CQ_COUNT: usize = 1;
 const CLIENT_PREFIX: &str = "tikv-client";
@@ -42,6 +47,7 @@ const CLIENT_PREFIX: &str = "tikv-client";
 #[async_trait]
 pub trait PdClient: Send + Sync + 'static {
     type KvClient: KvClient + Send + Sync + 'static;
+    type RequestCodec: RequestCodec;
 
     /// In transactional API, `region` is decoded (keys in raw format).
     async fn map_region_to_store(self: Arc<Self>, region: RegionWithLeader) -> Result<RegionStore>;
@@ -69,11 +75,11 @@ pub trait PdClient: Send + Sync + 'static {
 
     fn group_keys_by_region<K, K2>(
         self: Arc<Self>,
-        keys: impl Iterator<Item = K> + Send + Sync + 'static,
+        keys: impl Iterator<Item=K> + Send + Sync + 'static,
     ) -> BoxStream<'static, Result<(RegionId, Vec<K2>)>>
-    where
-        K: AsRef<Key> + Into<K2> + Send + Sync + 'static,
-        K2: Send + Sync + 'static,
+        where
+            K: AsRef<Key> + Into<K2> + Send + Sync + 'static,
+            K2: Send + Sync + 'static,
     {
         let keys = keys.peekable();
         stream_fn(keys, move |mut keys| {
@@ -95,7 +101,7 @@ pub trait PdClient: Send + Sync + 'static {
                 }
             }
         })
-        .boxed()
+            .boxed()
     }
 
     /// Returns a Stream which iterates over the contexts for each region covered by range.
@@ -126,7 +132,7 @@ pub trait PdClient: Send + Sync + 'static {
                 Ok(Some((Some(region_end), store)))
             }
         })
-        .boxed()
+            .boxed()
     }
 
     /// Returns a Stream which iterates over the contexts for ranges in the same region.
@@ -190,7 +196,7 @@ pub trait PdClient: Send + Sync + 'static {
                 }
             }
         })
-        .boxed()
+            .boxed()
     }
 
     fn decode_region(mut region: RegionWithLeader, enable_codec: bool) -> Result<RegionWithLeader> {
@@ -204,22 +210,27 @@ pub trait PdClient: Send + Sync + 'static {
     async fn update_leader(&self, ver_id: RegionVerId, leader: metapb::Peer) -> Result<()>;
 
     async fn invalidate_region_cache(&self, ver_id: RegionVerId);
+
+    fn get_request_codec(&self) -> Self::RequestCodec;
 }
 
 /// This client converts requests for the logical TiKV cluster into requests
 /// for a single TiKV store using PD and internal logic.
-pub struct PdRpcClient<KvC: KvConnect + Send + Sync + 'static = TikvConnect, Cl = Cluster> {
+pub struct PdRpcClient<C, KvC: KvConnect + Send + Sync + 'static = TikvConnect, Cl = Cluster> {
     pd: Arc<RetryClient<Cl>>,
     kv_connect: KvC,
     kv_client_cache: Arc<RwLock<HashMap<String, KvC::KvClient>>>,
     enable_codec: bool,
     region_cache: RegionCache<RetryClient<Cl>>,
     logger: Logger,
+    // TODO: change to a real codec.
+    _phantom: PhantomData<C>,
 }
 
 #[async_trait]
-impl<KvC: KvConnect + Send + Sync + 'static> PdClient for PdRpcClient<KvC> {
+impl<C: RequestCodec, KvC: KvConnect + Send + Sync + 'static> PdClient for PdRpcClient<C, KvC> {
     type KvClient = KvC::KvClient;
+    type RequestCodec = C;
 
     async fn map_region_to_store(self: Arc<Self>, region: RegionWithLeader) -> Result<RegionStore> {
         let store_id = region.get_store_id()?;
@@ -260,15 +271,19 @@ impl<KvC: KvConnect + Send + Sync + 'static> PdClient for PdRpcClient<KvC> {
     async fn invalidate_region_cache(&self, ver_id: RegionVerId) {
         self.region_cache.invalidate_region_cache(ver_id).await
     }
+
+    fn get_request_codec(&self) -> Self::RequestCodec {
+        todo!()
+    }
 }
 
-impl PdRpcClient<TikvConnect, Cluster> {
+impl<C> PdRpcClient<C, TikvConnect, Cluster> {
     pub async fn connect(
         pd_endpoints: &[String],
         config: Config,
         enable_codec: bool,
         logger: Logger,
-    ) -> Result<PdRpcClient> {
+    ) -> Result<PdRpcClient<C, TikvConnect, Cluster>> {
         PdRpcClient::new(
             config.clone(),
             |env, security_mgr| TikvConnect::new(env, security_mgr, config.timeout),
@@ -278,7 +293,7 @@ impl PdRpcClient<TikvConnect, Cluster> {
             enable_codec,
             logger,
         )
-        .await
+            .await
     }
 }
 
@@ -291,18 +306,18 @@ fn thread_name(prefix: &str) -> String {
         .unwrap_or_else(|| prefix.to_owned())
 }
 
-impl<KvC: KvConnect + Send + Sync + 'static, Cl> PdRpcClient<KvC, Cl> {
+impl<C, KvC: KvConnect + Send + Sync + 'static, Cl> PdRpcClient<C, KvC, Cl> {
     pub async fn new<PdFut, MakeKvC, MakePd>(
         config: Config,
         kv_connect: MakeKvC,
         pd: MakePd,
         enable_codec: bool,
         logger: Logger,
-    ) -> Result<PdRpcClient<KvC, Cl>>
-    where
-        PdFut: Future<Output = Result<RetryClient<Cl>>>,
-        MakeKvC: FnOnce(Arc<Environment>, Arc<SecurityManager>) -> KvC,
-        MakePd: FnOnce(Arc<Environment>, Arc<SecurityManager>) -> PdFut,
+    ) -> Result<PdRpcClient<C, KvC, Cl>>
+        where
+            PdFut: Future<Output=Result<RetryClient<Cl>>>,
+            MakeKvC: FnOnce(Arc<Environment>, Arc<SecurityManager>) -> KvC,
+            MakePd: FnOnce(Arc<Environment>, Arc<SecurityManager>) -> PdFut,
     {
         let env = Arc::new(
             EnvBuilder::new()
@@ -312,7 +327,7 @@ impl<KvC: KvConnect + Send + Sync + 'static, Cl> PdRpcClient<KvC, Cl> {
         );
         let security_mgr = Arc::new(
             if let (Some(ca_path), Some(cert_path), Some(key_path)) =
-                (&config.ca_path, &config.cert_path, &config.key_path)
+            (&config.ca_path, &config.cert_path, &config.key_path)
             {
                 SecurityManager::load(ca_path, cert_path, key_path)?
             } else {
@@ -329,6 +344,8 @@ impl<KvC: KvConnect + Send + Sync + 'static, Cl> PdRpcClient<KvC, Cl> {
             enable_codec,
             region_cache: RegionCache::new(pd),
             logger,
+            // TODO
+            _phantom: PhantomData,
         })
     }
 
@@ -352,10 +369,11 @@ impl<KvC: KvConnect + Send + Sync + 'static, Cl> PdRpcClient<KvC, Cl> {
 
 #[cfg(test)]
 pub mod test {
-    use super::*;
+    use futures::{executor, executor::block_on};
+
     use crate::mock::*;
 
-    use futures::{executor, executor::block_on};
+    use super::*;
 
     #[tokio::test]
     async fn test_kv_client_caching() {
@@ -396,7 +414,7 @@ pub mod test {
                 vec![1].into(),
                 vec![2].into(),
                 vec![3].into(),
-                vec![5, 2].into()
+                vec![5, 2].into(),
             ]
         );
         assert_eq!(
@@ -458,36 +476,36 @@ pub mod test {
             vec![
                 kvrpcpb::KeyRange {
                     start_key: k1.clone(),
-                    end_key: k2.clone()
+                    end_key: k2.clone(),
                 },
                 kvrpcpb::KeyRange {
                     start_key: k1,
-                    end_key: k_split.clone()
-                }
+                    end_key: k_split.clone(),
+                },
             ]
         );
         assert_eq!(ranges2.0, 2);
         assert_eq!(
             ranges2.1,
             vec![kvrpcpb::KeyRange {
                 start_key: k_split.clone(),
-                end_key: k3
+                end_key: k3,
             }]
         );
         assert_eq!(ranges3.0, 1);
         assert_eq!(
             ranges3.1,
             vec![kvrpcpb::KeyRange {
                 start_key: k2,
-                end_key: k_split.clone()
+                end_key: k_split.clone(),
             }]
         );
         assert_eq!(ranges4.0, 2);
         assert_eq!(
             ranges4.1,
             vec![kvrpcpb::KeyRange {
                 start_key: k_split,
-                end_key: k4
+                end_key: k4,
             }]
         );
         assert!(stream.next().is_none());

src/raw/client.rs

@@ -15,6 +15,7 @@ use crate::{
     request::{Collect, CollectSingle, Plan},
     Backoff, BoundRange, ColumnFamily, Key, KvPair, Result, Value,
 };
+use crate::request::request_codec::RequestCodec;
 
 const MAX_RAW_KV_SCAN_LIMIT: u32 = 10240;
 
@@ -26,15 +27,16 @@ const MAX_RAW_KV_SCAN_LIMIT: u32 = 10240;
 /// The returned results of raw request methods are [`Future`](std::future::Future)s that must be
 /// awaited to execute.
 #[derive(Clone)]
-pub struct Client<PdC: PdClient = PdRpcClient> {
+pub struct Client<C, PdC: PdClient = PdRpcClient<C>> {
     rpc: Arc<PdC>,
     cf: Option<ColumnFamily>,
     /// Whether to use the [`atomic mode`](Client::with_atomic_for_cas).
     atomic: bool,
     logger: Logger,
+    _phantom: std::marker::PhantomData<C>,
 }
 
-impl Client<PdRpcClient> {
+impl<C: RequestCodec> Client<C, PdRpcClient<C>> {
     /// Create a raw [`Client`] and connect to the TiKV cluster.
     ///
     /// Because TiKV is managed by a [PD](https://github.com/pingcap/pd/) cluster, the endpoints for
@@ -158,7 +160,7 @@ impl Client<PdRpcClient> {
     }
 }
 
-impl<PdC: PdClient> Client<PdC> {
+impl<C:RequestCodec, PdC: PdClient> Client<C, PdC> {
     /// Create a new 'get' request.
     ///
     /// Once resolved this request will result in the fetching of the value associated with the

src/raw/lowering.rs

@@ -5,17 +5,18 @@
 //! generated protobuf code, then calls the low-level ctor functions in the requests module.
 
 use std::{iter::Iterator, ops::Range, sync::Arc};
+use std::marker::PhantomData;
 
 use tikv_client_proto::{kvrpcpb, metapb};
 
-use crate::{raw::requests, BoundRange, ColumnFamily, Key, KvPair, Value};
+use crate::{BoundRange, ColumnFamily, Key, KvPair, raw::requests, Value};
 
 pub fn new_raw_get_request(key: Key, cf: Option<ColumnFamily>) -> kvrpcpb::RawGetRequest {
     requests::new_raw_get_request(key.into(), cf)
 }
 
 pub fn new_raw_batch_get_request(
-    keys: impl Iterator<Item = Key>,
+    keys: impl Iterator<Item=Key>,
     cf: Option<ColumnFamily>,
 ) -> kvrpcpb::RawBatchGetRequest {
     requests::new_raw_batch_get_request(keys.map(Into::into).collect(), cf)
@@ -31,7 +32,7 @@ pub fn new_raw_put_request(
 }
 
 pub fn new_raw_batch_put_request(
-    pairs: impl Iterator<Item = KvPair>,
+    pairs: impl Iterator<Item=KvPair>,
     cf: Option<ColumnFamily>,
     atomic: bool,
 ) -> kvrpcpb::RawBatchPutRequest {
@@ -47,7 +48,7 @@ pub fn new_raw_delete_request(
 }
 
 pub fn new_raw_batch_delete_request(
-    keys: impl Iterator<Item = Key>,
+    keys: impl Iterator<Item=Key>,
     cf: Option<ColumnFamily>,
 ) -> kvrpcpb::RawBatchDeleteRequest {
     requests::new_raw_batch_delete_request(keys.map(Into::into).collect(), cf)
@@ -78,7 +79,7 @@ pub fn new_raw_scan_request(
 }
 
 pub fn new_raw_batch_scan_request(
-    ranges: impl Iterator<Item = BoundRange>,
+    ranges: impl Iterator<Item=BoundRange>,
     each_limit: u32,
     key_only: bool,
     cf: Option<ColumnFamily>,
@@ -98,7 +99,7 @@ pub fn new_cas_request(
 pub fn new_raw_coprocessor_request(
     copr_name: String,
     copr_version_req: String,
-    ranges: impl Iterator<Item = BoundRange>,
+    ranges: impl Iterator<Item=BoundRange>,
     request_builder: impl Fn(metapb::Region, Vec<Range<Key>>) -> Vec<u8> + Send + Sync + 'static,
 ) -> requests::RawCoprocessorRequest {
     requests::new_raw_coprocessor_request(