Coding style.

Moved Runner class into worker.py and renamed it to Worker.

worker.py

@@ -3,11 +3,92 @@
 # Copyright (C) 2015-2016 Andrew Hamilton. All rights reserved.
 # Licensed under the Artistic License 2.0.
 
+import asyncio
 import os
+import signal
+import subprocess
+
+import psutil
 
 import tools
 
 
+def _make_process_nicest(pid):
+    process = psutil.Process(pid)
+    process.nice(19)
+    process.ionice(psutil.IOPRIO_CLASS_IDLE)
+
+
+class Worker:
+
+    def __init__(self, sandbox, is_already_paused, is_being_tested):
+        self.sandbox = sandbox
+        self.is_already_paused = is_already_paused
+        self.is_being_tested = is_being_tested
+        self.result = None
+        self.process = None
+        self.child_pid = None
+
+    @asyncio.coroutine
+    def create_process(self):
+        if self.sandbox is None:
+            command = [__file__]
+        else:
+            cache_path = os.path.join(os.getcwd(), tools.CACHE_PATH)
+            cache_mount = self.sandbox.mount_point + cache_path
+            subprocess.check_call(["sudo", "mount", "--bind", cache_path,
+                                   cache_mount])
+            command = self.sandbox.command([__file__])
+        create = asyncio.create_subprocess_exec(
+            *command, stdin=asyncio.subprocess.PIPE,
+            stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.PIPE)
+        self.process = yield from create
+        pid_line = yield from self.process.stdout.readline()
+        self.child_pid = int(pid_line.strip())
+
+    @asyncio.coroutine
+    def run_tool(self, path, tool):
+        self.process.stdin.write(("%s\n%s\n" %
+                                  (tool.__qualname__, path)).encode("utf-8"))
+        data = yield from self.process.stdout.readline()
+        return tools.Status(int(data))
+
+    @asyncio.coroutine
+    def job_runner(self, summary, log, jobs_added_event,
+                   appearance_changed_event):
+        yield from self.create_process()
+        _make_process_nicest(self.child_pid)
+        while True:
+            yield from jobs_added_event.wait()
+            while True:
+                # _regulate_temperature(log)  # My fan is broken
+                try:
+                    self.result = summary.get_closest_placeholder()
+                except StopIteration:
+                    self.result = None
+                    if summary.result_total == summary.completed_total:
+                        log.log_message("All results are up to date.")
+                        if self.is_being_tested:
+                            os.kill(os.getpid(), signal.SIGINT)
+                    break
+                yield from self.result.run(log, appearance_changed_event,
+                                           self)
+                summary.completed_total += 1
+            jobs_added_event.clear()
+
+    def pause(self):
+        if self.result is not None and \
+           self.result.status == tools.Status.running:
+            os.kill(self.child_pid, signal.SIGSTOP)
+            self.result.set_status(tools.Status.paused)
+
+    def continue_(self):
+        if self.result is not None and \
+           self.result.status == tools.Status.paused:
+            self.result.set_status(tools.Status.running)
+            os.kill(self.child_pid, signal.SIGCONT)
+
+
 def main():
     print(os.getpid(), flush=True)
     while True: