Merge #4061

4061: ra_proc_macro: cleanups here and there r=edwin0cheng a=Veetaha

r? @edwin0cheng 

Co-authored-by: veetaha <[email protected]>
Co-authored-by: Veetaha <[email protected]>

Author: bors[bot]

crates/ra_proc_macro/src/lib.rs

@@ -2,7 +2,7 @@
 //!
 //! We separate proc-macro expanding logic to an extern program to allow
 //! different implementations (e.g. wasm or dylib loading). And this crate
-//! is used to provide basic infrastructure  for communication between two
+//! is used to provide basic infrastructure for communication between two
 //! processes: Client (RA itself), Server (the external program)
 
 mod rpc;
@@ -13,6 +13,7 @@ use process::{ProcMacroProcessSrv, ProcMacroProcessThread};
 use ra_tt::{SmolStr, Subtree};
 use std::{
     ffi::OsStr,
+    io,
     path::{Path, PathBuf},
     sync::Arc,
 };
@@ -57,14 +58,10 @@ pub struct ProcMacroClient {
 }
 
 impl ProcMacroClient {
-    pub fn extern_process<I, S>(
-        process_path: &Path,
-        args: I,
-    ) -> Result<ProcMacroClient, std::io::Error>
-    where
-        I: IntoIterator<Item = S>,
-        S: AsRef<OsStr>,
-    {
+    pub fn extern_process(
+        process_path: PathBuf,
+        args: impl IntoIterator<Item = impl AsRef<OsStr>>,
+    ) -> io::Result<ProcMacroClient> {
         let (thread, process) = ProcMacroProcessSrv::run(process_path, args)?;
         Ok(ProcMacroClient {
             kind: ProcMacroClientKind::Process { process: Arc::new(process), thread },
@@ -84,7 +81,7 @@ impl ProcMacroClient {
             ProcMacroClientKind::Process { process, .. } => {
                 let macros = match process.find_proc_macros(dylib_path) {
                     Err(err) => {
-                        eprintln!("Fail to find proc macro. Error: {:#?}", err);
+                        eprintln!("Failed to find proc macros. Error: {:#?}", err);
                         return vec![];
                     }
                     Ok(macros) => macros,

crates/ra_proc_macro/src/msg.rs

@@ -1,4 +1,4 @@
-//! Defines messages for cross-process message based on `ndjson` wire protocol
+//! Defines messages for cross-process message passing based on `ndjson` wire protocol
 
 use std::{
     convert::TryFrom,
@@ -31,7 +31,7 @@ macro_rules! impl_try_from_response {
             fn try_from(value: Response) -> Result<Self, Self::Error> {
                 match value {
                     Response::$tag(res) => Ok(res),
-                    _ => Err("Fail to convert from response"),
+                    _ => Err(concat!("Failed to convert response to ", stringify!($tag))),
                 }
             }
         }
@@ -53,18 +53,16 @@ pub enum ErrorCode {
     ExpansionError,
 }
 
-pub trait Message: Sized + Serialize + DeserializeOwned {
-    fn read(r: &mut impl BufRead) -> io::Result<Option<Self>> {
-        let text = match read_json(r)? {
-            None => return Ok(None),
-            Some(text) => text,
-        };
-        let msg = serde_json::from_str(&text)?;
-        Ok(Some(msg))
+pub trait Message: Serialize + DeserializeOwned {
+    fn read(inp: &mut impl BufRead) -> io::Result<Option<Self>> {
+        Ok(match read_json(inp)? {
+            None => None,
+            Some(text) => Some(serde_json::from_str(&text)?),
+        })
     }
-    fn write(self, w: &mut impl Write) -> io::Result<()> {
+    fn write(self, out: &mut impl Write) -> io::Result<()> {
         let text = serde_json::to_string(&self)?;
-        write_json(w, &text)
+        write_json(out, &text)
     }
 }
 
@@ -73,15 +71,12 @@ impl Message for Response {}
 
 fn read_json(inp: &mut impl BufRead) -> io::Result<Option<String>> {
     let mut buf = String::new();
-    if inp.read_line(&mut buf)? == 0 {
-        return Ok(None);
-    }
-    // Remove ending '\n'
-    let buf = &buf[..buf.len() - 1];
-    if buf.is_empty() {
-        return Ok(None);
-    }
-    Ok(Some(buf.to_string()))
+    inp.read_line(&mut buf)?;
+    buf.pop(); // Remove traling '\n'
+    Ok(match buf.len() {
+        0 => None,
+        _ => Some(buf),
+    })
 }
 
 fn write_json(out: &mut impl Write, msg: &str) -> io::Result<()> {

crates/ra_proc_macro/src/process.rs

@@ -45,24 +45,23 @@ impl Drop for Process {
 }
 
 impl Process {
-    fn run<I, S>(process_path: &Path, args: I) -> Result<Process, io::Error>
-    where
-        I: IntoIterator<Item = S>,
-        S: AsRef<OsStr>,
-    {
-        let child = Command::new(process_path.clone())
+    fn run(
+        process_path: PathBuf,
+        args: impl IntoIterator<Item = impl AsRef<OsStr>>,
+    ) -> io::Result<Process> {
+        let child = Command::new(&process_path)
             .args(args)
             .stdin(Stdio::piped())
             .stdout(Stdio::piped())
             .stderr(Stdio::null())
             .spawn()?;
 
-        Ok(Process { path: process_path.into(), child })
+        Ok(Process { path: process_path, child })
     }
 
-    fn restart(&mut self) -> Result<(), io::Error> {
+    fn restart(&mut self) -> io::Result<()> {
         let _ = self.child.kill();
-        self.child = Command::new(self.path.clone())
+        self.child = Command::new(&self.path)
             .stdin(Stdio::piped())
             .stdout(Stdio::piped())
             .stderr(Stdio::null())
@@ -80,14 +79,10 @@ impl Process {
 }
 
 impl ProcMacroProcessSrv {
-    pub fn run<I, S>(
-        process_path: &Path,
-        args: I,
-    ) -> Result<(ProcMacroProcessThread, ProcMacroProcessSrv), io::Error>
-    where
-        I: IntoIterator<Item = S>,
-        S: AsRef<OsStr>,
-    {
+    pub fn run(
+        process_path: PathBuf,
+        args: impl IntoIterator<Item = impl AsRef<OsStr>>,
+    ) -> io::Result<(ProcMacroProcessThread, ProcMacroProcessSrv)> {
         let process = Process::run(process_path, args)?;
 
         let (task_tx, task_rx) = bounded(0);
@@ -201,7 +196,7 @@ fn send_request(
     mut writer: &mut impl Write,
     mut reader: &mut impl BufRead,
     req: Request,
-) -> Result<Option<Response>, io::Error> {
+) -> io::Result<Option<Response>> {
     req.write(&mut writer)?;
     Ok(Response::read(&mut reader)?)
 }

crates/ra_proc_macro/src/rpc.rs

@@ -1,9 +1,9 @@
-//! Data struture serialization related stuffs for RPC
+//! Data struture serialization related stuff for RPC
 //!
-//! Define all necessary rpc serialization data structure,
-//! which include ra_tt related data and some task messages.
-//! Although adding Serialize and Deserialize trait to ra_tt directly seem to be much easier,
-//! we deliberately duplicate the ra_tt struct with #[serde(with = "XXDef")]
+//! Defines all necessary rpc serialization data structures,
+//! which includes `ra_tt` related data and some task messages.
+//! Although adding `Serialize` and `Deserialize` traits to `ra_tt` directly seems
+//! to be much easier, we deliberately duplicate `ra_tt` structs with `#[serde(with = "XXDef")]`
 //! for separation of code responsibility.
 
 use ra_tt::{
@@ -34,15 +34,15 @@ pub struct ListMacrosResult {
 pub struct ExpansionTask {
     /// Argument of macro call.
     ///
-    /// In custom derive that would be a struct or enum; in attribute-like macro - underlying
+    /// In custom derive this will be a struct or enum; in attribute-like macro - underlying
     /// item; in function-like macro - the macro body.
     #[serde(with = "SubtreeDef")]
     pub macro_body: Subtree,
 
-    /// Names of macros to expand.
+    /// Name of macro to expand.
     ///
-    /// In custom derive those are names of derived traits (`Serialize`, `Getters`, etc.). In
-    /// attribute-like and functiona-like macros - single name of macro itself (`show_streams`).
+    /// In custom derive this is the name of the derived trait (`Serialize`, `Getters`, etc.).
+    /// In attribute-like and function-like macros - single name of macro itself (`show_streams`).
     pub macro_name: String,
 
     /// Possible attributes for the attribute-like macros.

crates/ra_proc_macro_srv/src/cli.rs

@@ -2,55 +2,43 @@
 
 use crate::{expand_task, list_macros};
 use ra_proc_macro::msg::{self, Message};
-
 use std::io;
 
-fn read_request() -> Result<Option<msg::Request>, io::Error> {
-    let stdin = io::stdin();
-    let mut stdin = stdin.lock();
-    msg::Request::read(&mut stdin)
-}
-
-fn write_response(res: Result<msg::Response, String>) -> Result<(), io::Error> {
-    let msg: msg::Response = match res {
-        Ok(res) => res,
-        Err(err) => msg::Response::Error(msg::ResponseError {
-            code: msg::ErrorCode::ExpansionError,
-            message: err,
-        }),
-    };
-
-    let stdout = io::stdout();
-    let mut stdout = stdout.lock();
-    msg.write(&mut stdout)
-}
-
 pub fn run() {
     loop {
         let req = match read_request() {
             Err(err) => {
-                eprintln!("Read message error on ra_proc_macro_srv: {}", err.to_string());
+                eprintln!("Read message error on ra_proc_macro_srv: {}", err);
                 continue;
             }
             Ok(None) => continue,
             Ok(Some(req)) => req,
         };
 
-        match req {
-            msg::Request::ListMacro(task) => {
-                if let Err(err) =
-                    write_response(list_macros(&task).map(|it| msg::Response::ListMacro(it)))
-                {
-                    eprintln!("Write message error on list macro: {}", err);
-                }
-            }
+        let res = match req {
+            msg::Request::ListMacro(task) => Ok(msg::Response::ListMacro(list_macros(&task))),
             msg::Request::ExpansionMacro(task) => {
-                if let Err(err) =
-                    write_response(expand_task(&task).map(|it| msg::Response::ExpansionMacro(it)))
-                {
-                    eprintln!("Write message error on expansion macro: {}", err);
-                }
+                expand_task(&task).map(msg::Response::ExpansionMacro)
             }
+        };
+
+        let msg = res.unwrap_or_else(|err| {
+            msg::Response::Error(msg::ResponseError {
+                code: msg::ErrorCode::ExpansionError,
+                message: err,
+            })
+        });
+
+        if let Err(err) = write_response(msg) {
+            eprintln!("Write message error: {}", err);
         }
     }
 }
+
+fn read_request() -> io::Result<Option<msg::Request>> {
+    msg::Request::read(&mut io::stdin().lock())
+}
+
+fn write_response(msg: msg::Response) -> io::Result<()> {
+    msg.write(&mut io::stdout().lock())
+}