Use rust-format for generated files

Re libp2p#49

Author: akoptelov

node/lib/Cargo.toml

@@ -22,3 +22,4 @@ snark = { path = "../snark" }
 
 [build-dependencies]
 regex = "1"
+rust-format = "0.3"

node/lib/build.rs

@@ -67,7 +67,9 @@ fn main() -> Result<(), Box<dyn Error>> {
             let Some(line) = lines.next() else { break };
             let line = line.unwrap();
 
-            let Some(matches) = action_def_re.captures(&line) else { continue };
+            let Some(matches) = action_def_re.captures(&line) else {
+                continue;
+            };
             match &matches[1] {
                 "struct" => {
                     if let Some(action_name) = matches.get(2) {
@@ -198,9 +200,9 @@ fn main() -> Result<(), Box<dyn Error>> {
     let contents =
         format!("{use_deps}\n\n{use_statements}\n\n{action_kind_def}\n\n{action_kind_get_impls}\n");
 
-    fs::write(crate_dir.join("src/action_kind.rs"), contents)?;
-
-    std::process::Command::new("cargo").arg("fmt").output()?;
+    let path = crate_dir.join("src/action_kind.rs");
+    fs::write(&path, contents)?;
+    rust_format::RustFmt::default().format_file(&path).expect("failed to format generated file");
 
     Ok(())
 }

snarker/Cargo.toml

@@ -29,3 +29,4 @@ p2p = { path = "../p2p" }
 
 [build-dependencies]
 regex = "1"
+rust-format = "0.3"

snarker/build.rs

@@ -6,6 +6,7 @@ use std::io::{self, BufRead, BufReader};
 use std::path::PathBuf;
 
 use regex::Regex;
+use rust_format::Formatter;
 
 fn visit_dirs(dir: &PathBuf, cb: &mut dyn FnMut(&DirEntry)) -> io::Result<()> {
     if dir.is_dir() {
@@ -72,7 +73,9 @@ fn main() -> Result<(), Box<dyn Error>> {
             let Some(line) = lines.next() else { break };
             let line = line.unwrap();
 
-            let Some(matches) = action_def_re.captures(&line) else { continue };
+            let Some(matches) = action_def_re.captures(&line) else {
+                continue;
+            };
             match &matches[1] {
                 "struct" => {
                     if let Some(action_name) = matches.get(2) {
@@ -207,9 +210,9 @@ fn main() -> Result<(), Box<dyn Error>> {
     let contents =
         format!("{use_deps}\n\n{use_statements}\n\n{action_kind_def}\n\n{action_kind_get_impls}\n");
 
-    fs::write(crate_dir.join("src/action_kind.rs"), contents)?;
-
-    std::process::Command::new("cargo").arg("fmt").output()?;
+    let path = crate_dir.join("src/action_kind.rs");
+    fs::write(&path, contents)?;
+    rust_format::RustFmt::default().format_file(&path).expect("failed to format generated file");
 
     Ok(())
 }