Replace rust-protobuf with prost

Cargo.toml

@@ -11,16 +11,25 @@ documentation = "https://docs.rs/raft"
 description = "The rust language implementation of Raft algorithm."
 categories = ["algorithms", "database-implementations"]
 edition = "2018"
+build = "build.rs"
+
+[build-dependencies]
+protobuf-build = "0.3"
 
 [features]
 default = []
+gen = []
 # Enable failpoints
 failpoint = ["fail"]
 
 # Make sure to synchronize updates with Harness.
 [dependencies]
 log = ">0.2"
-protobuf = "~2.0-2.2"
+protobuf = "~2.1-2.2"
+lazy_static = "1.3.0"
+prost = "0.5"
+prost-derive = "0.5"
+bytes = "0.4.11"
 quick-error = "1.2.2"
 rand = "0.5.4"
 hashbrown = "0.1"

build.rs

@@ -0,0 +1,81 @@
+// Copyright 2019 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use protobuf_build::*;
+use std::fs::{read_dir, File};
+use std::io::Write;
+
+fn main() {
+    // This build script creates files in the `src` directory. Since that is
+    // outside Cargo's OUT_DIR it will cause an error when this crate is used
+    // as a dependency. Therefore, the user must opt-in to regenerating the
+    // Rust files.
+    if !cfg!(feature = "gen") {
+        println!("cargo:rerun-if-changed=build.rs");
+        return;
+    }
+
+    check_protoc_version();
+
+    let file_names: Vec<_> = read_dir("proto")
+        .expect("Couldn't read proto directory")
+        .filter_map(|e| {
+            let e = e.expect("Couldn't list file");
+            if e.file_type().expect("File broken").is_dir() {
+                None
+            } else {
+                Some(format!("proto/{}", e.file_name().to_string_lossy()))
+            }
+        })
+        .collect();
+
+    for f in &file_names {
+        println!("cargo:rerun-if-changed={}", f);
+    }
+
+    // Generate Prost files.
+    generate_prost_files(&file_names, "src/prost");
+    let mod_names = module_names_for_dir("src/prost");
+    generate_wrappers(
+        &mod_names
+            .iter()
+            .map(|m| format!("src/prost/{}.rs", m))
+            .collect::<Vec<_>>(),
+        "src/prost",
+    );
+    generate_prost_rs(&mod_names);
+}
+
+fn generate_prost_rs(mod_names: &[String]) {
+    let mut text = "#![allow(dead_code)]\n\
+                    #![allow(missing_docs)]\n\
+                    #![allow(clippy::all)]\n\n"
+        .to_owned();
+
+    for mod_name in mod_names {
+        text.push_str("pub mod ");
+        text.push_str(mod_name);
+        text.push_str("{\n");
+        text.push_str("include!(\"prost/");
+        text.push_str(mod_name);
+        text.push_str(".rs\");");
+        text.push_str("include!(\"prost/wrapper_");
+        text.push_str(mod_name);
+        text.push_str(".rs\");");
+        text.push_str("}\n\n");
+    }
+
+    let mut lib = File::create("src/prost.rs").expect("Could not create prost.rs");
+    lib.write_all(text.as_bytes())
+        .expect("Could not write prost.rs");
+}

examples/five_mem_node/main.rs

@@ -13,7 +13,7 @@
 #[macro_use]
 extern crate log;
 extern crate env_logger;
-extern crate protobuf;
+extern crate prost;
 extern crate raft;
 extern crate regex;
 
@@ -23,7 +23,7 @@ use std::sync::{Arc, Mutex};
 use std::time::{Duration, Instant};
 use std::{str, thread};
 
-use protobuf::Message as PbMessage;
+use prost::Message as ProstMsg;
 use raft::eraftpb::ConfState;
 use raft::storage::MemStorage;
 use raft::{prelude::*, StateRole};
@@ -224,8 +224,8 @@ fn on_ready(
             }
             if let EntryType::EntryConfChange = entry.get_entry_type() {
                 // For conf change messages, make them effective.
-                let mut cc = ConfChange::new();
-                cc.merge_from_bytes(entry.get_data()).unwrap();
+                let mut cc = ConfChange::new_();
+                ProstMsg::merge(&mut cc, entry.get_data()).unwrap();
                 let node_id = cc.get_node_id();
                 match cc.get_change_type() {
                     ConfChangeType::AddNode => raft_group.raft.add_node(node_id).unwrap(),