1 files changed, 123 insertions, 0 deletions
diff --git a/src/tools/clippy/lintcheck/src/recursive.rs b/src/tools/clippy/lintcheck/src/recursive.rs
new file mode 100644
index 000000000..49072e651
--- /dev/null
+++ b/src/tools/clippy/lintcheck/src/recursive.rs
@@ -0,0 +1,123 @@
+//! In `--recursive` mode we set the `lintcheck` binary as the `RUSTC_WRAPPER` of `cargo check`,
+//! this allows [`crate::driver`] to be run for every dependency. The driver connects to
+//! [`LintcheckServer`] to ask if it should be skipped, and if not sends the stderr of running
+//! clippy on the crate to the server
+
+use crate::ClippyWarning;
+use crate::RecursiveOptions;
+
+use std::collections::HashSet;
+use std::io::{BufRead, BufReader, Read, Write};
+use std::net::{SocketAddr, TcpListener, TcpStream};
+use std::sync::{Arc, Mutex};
+use std::thread;
+
+use cargo_metadata::diagnostic::Diagnostic;
+use crossbeam_channel::{Receiver, Sender};
+use serde::de::DeserializeOwned;
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Eq, Hash, PartialEq, Clone, Serialize, Deserialize)]
+pub(crate) struct DriverInfo {
+    pub package_name: String,
+    pub crate_name: String,
+    pub version: String,
+}
+
+pub(crate) fn serialize_line<T, W>(value: &T, writer: &mut W)
+where
+    T: Serialize,
+    W: Write,
+{
+    let mut buf = serde_json::to_vec(&value).expect("failed to serialize");
+    buf.push(b'\n');
+    writer.write_all(&buf).expect("write_all failed");
+}
+
+pub(crate) fn deserialize_line<T, R>(reader: &mut R) -> T
+where
+    T: DeserializeOwned,
+    R: BufRead,
+{
+    let mut string = String::new();
+    reader.read_line(&mut string).expect("read_line failed");
+    serde_json::from_str(&string).expect("failed to deserialize")
+}
+
+fn process_stream(
+    stream: TcpStream,
+    sender: &Sender<ClippyWarning>,
+    options: &RecursiveOptions,
+    seen: &Mutex<HashSet<DriverInfo>>,
+) {
+    let mut stream = BufReader::new(stream);
+
+    let driver_info: DriverInfo = deserialize_line(&mut stream);
+
+    let unseen = seen.lock().unwrap().insert(driver_info.clone());
+    let ignored = options.ignore.contains(&driver_info.package_name);
+    let should_run = unseen && !ignored;
+
+    serialize_line(&should_run, stream.get_mut());
+
+    let mut stderr = String::new();
+    stream.read_to_string(&mut stderr).unwrap();
+
+    let messages = stderr
+        .lines()
+        .filter_map(|json_msg| serde_json::from_str::<Diagnostic>(json_msg).ok())
+        .filter_map(|diag| ClippyWarning::new(diag, &driver_info.package_name, &driver_info.version));
+
+    for message in messages {
+        sender.send(message).unwrap();
+    }
+}
+
+pub(crate) struct LintcheckServer {
+    pub local_addr: SocketAddr,
+    receiver: Receiver<ClippyWarning>,
+    sender: Arc<Sender<ClippyWarning>>,
+}
+
+impl LintcheckServer {
+    pub fn spawn(options: RecursiveOptions) -> Self {
+        let listener = TcpListener::bind("localhost:0").unwrap();
+        let local_addr = listener.local_addr().unwrap();
+
+        let (sender, receiver) = crossbeam_channel::unbounded::<ClippyWarning>();
+        let sender = Arc::new(sender);
+        // The spawned threads hold a `Weak<Sender>` so that they don't keep the channel connected
+        // indefinitely
+        let sender_weak = Arc::downgrade(&sender);
+
+        // Ignore dependencies multiple times, e.g. for when it's both checked and compiled for a
+        // build dependency
+        let seen = Mutex::default();
+
+        thread::spawn(move || {
+            thread::scope(|s| {
+                s.spawn(|| {
+                    while let Ok((stream, _)) = listener.accept() {
+                        let sender = sender_weak.upgrade().expect("received connection after server closed");
+                        let options = &options;
+                        let seen = &seen;
+                        s.spawn(move || process_stream(stream, &sender, options, seen));
+                    }
+                });
+            });
+        });
+
+        Self {
+            local_addr,
+            receiver,
+            sender,
+        }
+    }
+
+    pub fn warnings(self) -> impl Iterator<Item = ClippyWarning> {
+        // causes the channel to become disconnected so that the receiver iterator ends
+        drop(self.sender);
+
+        self.receiver.into_iter()
+    }
+}