[test-runner] Improve test execution without tmp files for output.

tools/testrunner/local/commands.py

Index: tools/testrunner/local/commands.py
diff --git a/tools/testrunner/local/commands.py b/tools/testrunner/local/commands.py
index d6445d0c7a67838f863cef5b6f2370f32f8790aa..4d74165edbb5f63b54819178b37c30dc1e9f5ff1 100644
--- a/tools/testrunner/local/commands.py
+++ b/tools/testrunner/local/commands.py
@@ -27,27 +27,13 @@
 
 
 import os
-import signal
 import subprocess
-import sys
-import tempfile
-import time
+from threading import Timer
 
 from ..local import utils
 from ..objects import output
 
 
-def KillProcessWithID(pid):
-  if utils.IsWindows():
-    os.popen('taskkill /T /F /PID %d' % pid)
-  else:
-    os.kill(pid, signal.SIGTERM)
-
-
-MAX_SLEEP_TIME = 0.1
-INITIAL_SLEEP_TIME = 0.0001
-SLEEP_TIME_FACTOR = 1.25
-
 SEM_INVALID_VALUE = -1
 SEM_NOGPFAULTERRORBOX = 0x0002  # Microsoft Platform SDK WinBase.h
 
@@ -76,76 +62,36 @@ def RunProcess(verbose, timeout, args, **rest):
     prev_error_mode = Win32SetErrorMode(error_mode)
     Win32SetErrorMode(error_mode | prev_error_mode)
   process = subprocess.Popen(
-    shell=utils.IsWindows(),
     args=popen_args,
+    stdout=subprocess.PIPE,
+    stderr=subprocess.PIPE,
     **rest
   )
   if (utils.IsWindows() and prev_error_mode != SEM_INVALID_VALUE):
     Win32SetErrorMode(prev_error_mode)
-  # Compute the end time - if the process crosses this limit we
-  # consider it timed out.
-  if timeout is None: end_time = None
-  else: end_time = time.time() + timeout
-  timed_out = False
-  # Repeatedly check the exit code from the process in a
-  # loop and keep track of whether or not it times out.
-  exit_code = None
-  sleep_time = INITIAL_SLEEP_TIME
-  while exit_code is None:
-    if (not end_time is None) and (time.time() >= end_time):
-      # Kill the process and wait for it to exit.
-      KillProcessWithID(process.pid)
-      exit_code = process.wait()
-      timed_out = True
-    else:
-      exit_code = process.poll()
-      time.sleep(sleep_time)
-      sleep_time = sleep_time * SLEEP_TIME_FACTOR
-      if sleep_time > MAX_SLEEP_TIME:
-        sleep_time = MAX_SLEEP_TIME
-  return (exit_code, timed_out)
-
 
-def PrintError(string):
-  sys.stderr.write(string)
-  sys.stderr.write("\n")
+  def kill_process(process, timeout_result):
+    timeout_result[0] = True
+    try:
+      process.kill()
+    except OSError:
+      sys.stderr.write('Error: Process %s already ended.\n' % process.pid)
 
+  # Pseudo object to communicate with timer thread.
+  timeout_result = [False]
 
-def CheckedUnlink(name):
-  # On Windows, when run with -jN in parallel processes,
-  # OS often fails to unlink the temp file. Not sure why.
-  # Need to retry.
-  # Idea from https://bugs.webkit.org/attachment.cgi?id=75982&action=prettypatch
-  retry_count = 0
-  while retry_count < 30:
-    try:
-      os.unlink(name)
-      return
-    except OSError, e:
-      retry_count += 1
-      time.sleep(retry_count * 0.1)
-  PrintError("os.unlink() " + str(e))
+  timer = Timer(timeout, kill_process, [process, timeout_result])
+  timer.start()
+  stdout, stderr = process.communicate()
+  timer.cancel()
+  return process.returncode, timeout_result[0], stdout, stderr
 
 
 def Execute(args, verbose=False, timeout=None):
-  try:
-    args = [ c for c in args if c != "" ]
-    (fd_out, outname) = tempfile.mkstemp()
-    (fd_err, errname) = tempfile.mkstemp()
-    (exit_code, timed_out) = RunProcess(
-      verbose,
-      timeout,
-      args=args,
-      stdout=fd_out,
-      stderr=fd_err
-    )
-  finally:
-    # TODO(machenbach): A keyboard interrupt before the assignment to
-    # fd_out|err can lead to reference errors here.
-    os.close(fd_out)
-    os.close(fd_err)
-    out = file(outname).read()
-    errors = file(errname).read()
-    CheckedUnlink(outname)
-    CheckedUnlink(errname)
-  return output.Output(exit_code, timed_out, out, errors)
+  args = [ c for c in args if c != "" ]
+  exit_code, timed_out, stdout, stderr = RunProcess(
+    verbose,
+    timeout,
+    args=args,
+  )
+  return output.Output(exit_code, timed_out, stdout, stderr)