Promote the src/tools crate to the top-level workspace.

The 'src' and 'tests' top-level directories now contain tools sources
and integration tests for any of the library crates.

src/filetest/concurrent.rs

@@ -0,0 +1,150 @@
+//! Run tests concurrently.
+//!
+//! This module provides the `ConcurrentRunner` struct which uses a pool of threads to run tests
+//! concurrently.
+
+use std::panic::catch_unwind;
+use std::path::{Path, PathBuf};
+use std::sync::mpsc::{channel, Sender, Receiver};
+use std::sync::{Arc, Mutex};
+use std::thread;
+use std::time::Duration;
+use num_cpus;
+use filetest::{TestResult, runone};
+
+// Request sent to worker threads contains jobid and path.
+struct Request(usize, PathBuf);
+
+/// Reply from worker thread,
+pub enum Reply {
+    Starting { jobid: usize, thread_num: usize },
+    Done { jobid: usize, result: TestResult },
+    Tick,
+}
+
+/// Manage threads that run test jobs concurrently.
+pub struct ConcurrentRunner {
+    // Channel for sending requests to the worker threads.
+    // The workers are sharing the receiver with an `Arc<Mutex<Receiver>>`.
+    // This is `None` when shutting down.
+    request_tx: Option<Sender<Request>>,
+
+    // Channel for receiving replies from the workers.
+    // Workers have their own `Sender`.
+    reply_rx: Receiver<Reply>,
+
+    handles: Vec<thread::JoinHandle<()>>,
+}
+
+impl ConcurrentRunner {
+    /// Create a new `ConcurrentRunner` with threads spun up.
+    pub fn new() -> ConcurrentRunner {
+        let (request_tx, request_rx) = channel();
+        let request_mutex = Arc::new(Mutex::new(request_rx));
+        let (reply_tx, reply_rx) = channel();
+
+        heartbeat_thread(reply_tx.clone());
+
+        let handles = (0..num_cpus::get())
+            .map(|num| worker_thread(num, request_mutex.clone(), reply_tx.clone()))
+            .collect();
+
+        ConcurrentRunner {
+            request_tx: Some(request_tx),
+            reply_rx: reply_rx,
+            handles: handles,
+        }
+    }
+
+    /// Shut down worker threads orderly. They will finish any queued jobs first.
+    pub fn shutdown(&mut self) {
+        self.request_tx = None;
+    }
+
+    /// Join all the worker threads.
+    pub fn join(&mut self) {
+        assert!(self.request_tx.is_none(), "must shutdown before join");
+        for h in self.handles.drain(..) {
+            if let Err(e) = h.join() {
+                println!("worker panicked: {:?}", e);
+            }
+        }
+    }
+
+    /// Add a new job to the queues.
+    pub fn put(&mut self, jobid: usize, path: &Path) {
+        self.request_tx
+            .as_ref()
+            .expect("cannot push after shutdown")
+            .send(Request(jobid, path.to_owned()))
+            .expect("all the worker threads are gone");
+    }
+
+    /// Get a job reply without blocking.
+    pub fn try_get(&mut self) -> Option<Reply> {
+        self.reply_rx.try_recv().ok()
+    }
+
+    /// Get a job reply, blocking until one is available.
+    pub fn get(&mut self) -> Option<Reply> {
+        self.reply_rx.recv().ok()
+    }
+}
+
+/// Spawn a heartbeat thread which sends ticks down the reply channel every second.
+/// This lets us implement timeouts without the not yet stable `recv_timeout`.
+fn heartbeat_thread(replies: Sender<Reply>) -> thread::JoinHandle<()> {
+    thread::Builder::new()
+        .name("heartbeat".to_string())
+        .spawn(move || {
+            while replies.send(Reply::Tick).is_ok() {
+                thread::sleep(Duration::from_secs(1));
+            }
+        })
+        .unwrap()
+}
+
+/// Spawn a worker thread running tests.
+fn worker_thread(thread_num: usize,
+                 requests: Arc<Mutex<Receiver<Request>>>,
+                 replies: Sender<Reply>)
+                 -> thread::JoinHandle<()> {
+    thread::Builder::new()
+        .name(format!("worker #{}", thread_num))
+        .spawn(move || {
+            loop {
+                // Lock the mutex only long enough to extract a request.
+                let Request(jobid, path) = match requests.lock().unwrap().recv() {
+                    Err(..) => break, // TX end shuit down. exit thread.
+                    Ok(req) => req,
+                };
+
+                // Tell them we're starting this job.
+                // The receiver should always be present for this as long as we have jobs.
+                replies.send(Reply::Starting {
+                        jobid: jobid,
+                        thread_num: thread_num,
+                    })
+                    .unwrap();
+
+                let result = catch_unwind(|| runone::run(path.as_path())).unwrap_or_else(|e| {
+                    // The test panicked, leaving us a `Box<Any>`.
+                    // Panics are usually strings.
+                    if let Some(msg) = e.downcast_ref::<String>() {
+                        Err(format!("panicked in worker #{}: {}", thread_num, msg))
+                    } else if let Some(msg) = e.downcast_ref::<&'static str>() {
+                        Err(format!("panicked in worker #{}: {}", thread_num, msg))
+                    } else {
+                        Err(format!("panicked in worker #{}", thread_num))
+                    }
+                });
+
+                replies.send(Reply::Done {
+                        jobid: jobid,
+                        result: result,
+                    })
+                    .unwrap();
+            }
+        })
+        .unwrap()
+}