Add initial wasm32-wasi support (#416)

src/cache.rs

@@ -1,3 +1,9 @@
+// cacache uses asyncd-std which has no wasm support, so currently no caching support on wasm
+#![cfg_attr(
+    target_family = "wasm",
+    allow(unused_imports, unused_variables, dead_code)
+)]
+
 use std::collections::hash_map::DefaultHasher;
 use std::fs::{create_dir_all, File, Metadata};
 use std::hash::{Hash, Hasher};
@@ -5,6 +11,7 @@ use std::io::Write;
 use std::path::Path;
 
 use anyhow::Result;
+#[cfg(not(target_family = "wasm"))]
 use cacache::Error::EntryNotFound;
 use filetime::FileTime;
 use log::error;
@@ -107,6 +114,7 @@ pub fn get(
         return None;
     };
 
+    #[cfg(not(target_family = "wasm"))] // cacache needs async-std which doesn't support wasm
     match cacache::read_sync(cache_dir(), cache_key(path, settings, autofix)) {
         Ok(encoded) => match bincode::deserialize::<CheckResult>(&encoded[..]) {
             Ok(CheckResult {
@@ -137,12 +145,14 @@ pub fn set(
         return;
     };
 
+    #[cfg(not(target_family = "wasm"))] // modification date not supported on wasm
     let check_result = CheckResultRef {
         metadata: &CacheMetadata {
             mtime: FileTime::from_last_modification_time(metadata).unix_seconds(),
         },
         messages,
     };
+    #[cfg(not(target_family = "wasm"))] // cacache needs async-std which doesn't support wasm
     if let Err(e) = cacache::write_sync(
         cache_dir(),
         cache_key(path, settings, autofix),

src/linter.rs

@@ -4,6 +4,7 @@ use std::io::Write;
 use std::path::Path;
 
 use anyhow::Result;
+#[cfg(not(target_family = "wasm"))]
 use log::debug;
 use rustpython_parser::lexer::LexResult;
 use rustpython_parser::{lexer, parser};
@@ -122,6 +123,7 @@ pub fn lint_stdin(
         .collect())
 }
 
+#[cfg_attr(target_family = "wasm", allow(unused_variables))]
 pub fn lint_path(
     path: &Path,
     settings: &Settings,
@@ -131,6 +133,7 @@ pub fn lint_path(
     let metadata = path.metadata()?;
 
     // Check the cache.
+    #[cfg(not(target_family = "wasm"))]
     if let Some(messages) = cache::get(path, &metadata, settings, autofix, mode) {
         debug!("Cache hit for: {}", path.to_string_lossy());
         return Ok(messages);
@@ -166,6 +169,7 @@ pub fn lint_path(
             filename: path.to_string_lossy().to_string(),
         })
         .collect();
+    #[cfg(not(target_family = "wasm"))]
     cache::set(path, &metadata, settings, autofix, &messages, mode);
 
     Ok(messages)

src/main.rs

@@ -9,9 +9,11 @@ use clap::Parser;
 use colored::Colorize;
 use log::{debug, error};
 use notify::{raw_watcher, RecursiveMode, Watcher};
+#[cfg(not(target_family = "wasm"))]
 use rayon::prelude::*;
 use walkdir::DirEntry;
 
+#[cfg(not(target_family = "wasm"))]
 use ruff::cache;
 use ruff::checks::CheckCode;
 use ruff::checks::CheckKind;
@@ -29,9 +31,24 @@ use ruff::settings::RawSettings;
 use ruff::settings::{FilePattern, PerFileIgnore, Settings};
 use ruff::tell_user;
 
+#[cfg(feature = "update-informer")]
 const CARGO_PKG_NAME: &str = env!("CARGO_PKG_NAME");
+#[cfg(feature = "update-informer")]
 const CARGO_PKG_VERSION: &str = env!("CARGO_PKG_VERSION");
 
+/// Shim that calls par_iter except for wasm because there's no wasm support in rayon yet
+/// (there is a shim to be used for the web, but it requires js cooperation)
+/// Unfortunately, ParallelIterator does not implement Iterator so the signatures diverge
+#[cfg(not(target_family = "wasm"))]
+fn par_iter<T: Sync>(iterable: &Vec<T>) -> impl ParallelIterator<Item = &T> {
+    iterable.par_iter()
+}
+
+#[cfg(target_family = "wasm")]
+fn par_iter<T: Sync>(iterable: &Vec<T>) -> impl Iterator<Item = &T> {
+    iterable.iter()
+}
+
 #[cfg(feature = "update-informer")]
 fn check_for_updates() {
     use update_informer::{registry, Check};
@@ -104,8 +121,7 @@ fn run_once(
     debug!("Identified files to lint in: {:?}", duration);
 
     let start = Instant::now();
-    let mut messages: Vec<Message> = paths
-        .par_iter()
+    let mut messages: Vec<Message> = par_iter(&paths)
         .map(|entry| {
             match entry {
                 Ok(entry) => {
@@ -160,8 +176,7 @@ fn add_noqa(files: &[PathBuf], settings: &Settings) -> Result<usize> {
     debug!("Identified files to lint in: {:?}", duration);
 
     let start = Instant::now();
-    let modifications: usize = paths
-        .par_iter()
+    let modifications: usize = par_iter(&paths)
         .map(|entry| match entry {
             Ok(entry) => {
                 let path = entry.path();
@@ -190,8 +205,7 @@ fn autoformat(files: &[PathBuf], settings: &Settings) -> Result<usize> {
     debug!("Identified files to lint in: {:?}", duration);
 
     let start = Instant::now();
-    let modifications = paths
-        .par_iter()
+    let modifications = par_iter(&paths)
         .map(|entry| {
             let path = entry.path();
             autoformat_path(path)
@@ -302,6 +316,7 @@ fn inner_main() -> Result<ExitCode> {
         return Ok(ExitCode::SUCCESS);
     }
 
+    #[cfg(not(target_family = "wasm"))]
     cache::init()?;
 
     let mut printer = Printer::new(cli.format, cli.verbose);

src/printer.rs

@@ -104,6 +104,7 @@ impl Printer {
     }
 
     pub fn clear_screen(&mut self) -> Result<()> {
+        #[cfg(not(target_family = "wasm"))]
         clearscreen::clear()?;
         Ok(())
     }