Introduce a dynamic process pool for the local test driver

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 4f3dc51e02b20d763e80adb3d65c9e8433ebd21d..d6445d0c7a67838f863cef5b6f2370f32f8790aa 100644
--- a/tools/testrunner/local/commands.py
+++ b/tools/testrunner/local/commands.py
@@ -64,49 +64,46 @@ def Win32SetErrorMode(mode):
 
 
 def RunProcess(verbose, timeout, args, **rest):
-  try:
-    if verbose: print "#", " ".join(args)
-    popen_args = args
-    prev_error_mode = SEM_INVALID_VALUE
-    if utils.IsWindows():
-      popen_args = subprocess.list2cmdline(args)
-      # Try to change the error mode to avoid dialogs on fatal errors. Don't
-      # touch any existing error mode flags by merging the existing error mode.
-      # See http://blogs.msdn.com/oldnewthing/archive/2004/07/27/198410.aspx.
-      error_mode = SEM_NOGPFAULTERRORBOX
-      prev_error_mode = Win32SetErrorMode(error_mode)
-      Win32SetErrorMode(error_mode | prev_error_mode)
-    process = subprocess.Popen(
-      shell=utils.IsWindows(),
-      args=popen_args,
-      **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)
-  except KeyboardInterrupt:
-    raise
+  if verbose: print "#", " ".join(args)
+  popen_args = args
+  prev_error_mode = SEM_INVALID_VALUE
+  if utils.IsWindows():
+    popen_args = subprocess.list2cmdline(args)
+    # Try to change the error mode to avoid dialogs on fatal errors. Don't
+    # touch any existing error mode flags by merging the existing error mode.
+    # See http://blogs.msdn.com/oldnewthing/archive/2004/07/27/198410.aspx.
+    error_mode = SEM_NOGPFAULTERRORBOX
+    prev_error_mode = Win32SetErrorMode(error_mode)
+    Win32SetErrorMode(error_mode | prev_error_mode)
+  process = subprocess.Popen(
+    shell=utils.IsWindows(),
+    args=popen_args,
+    **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):
@@ -142,11 +139,9 @@ def Execute(args, verbose=False, timeout=None):
       stdout=fd_out,
       stderr=fd_err
     )
-  except KeyboardInterrupt:
-    raise
-  except:
-    raise
   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()