Revert 212020 "Move Python setup/tear down logic into Forwarder ..."

trunk/src/build/android/pylib/forwarder.py

Index: trunk/src/build/android/pylib/forwarder.py
===================================================================
--- trunk/src/build/android/pylib/forwarder.py	(revision 212053)
+++ trunk/src/build/android/pylib/forwarder.py	(working copy)
@@ -2,49 +2,24 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import fcntl
 import logging
 import os
-import psutil
 import re
 import sys
+import threading
 import time
 
 import android_commands
 import cmd_helper
 import constants
 
-from pylib import valgrind_tools
+from pylib import pexpect
 
 
 def _MakeBinaryPath(build_type, binary_name):
   return os.path.join(cmd_helper.OutDirectory.get(), build_type, binary_name)
 
 
-def _GetProcessStartTime(pid):
-  return psutil.Process(pid).create_time
-
-
-class _FileLock(object):
-  """With statement-aware implementation of a file lock.
-
-  File locks are needed for cross-process synchronization when the
-  multiprocessing Python module is used.
-  """
-  def __init__(self, path):
-    self._path = path
-
-  def __enter__(self):
-    self._fd = os.open(self._path, os.O_RDONLY | os.O_CREAT)
-    if self._fd < 0:
-      raise Exception('Could not open file %s for reading' % self._path)
-    fcntl.flock(self._fd, fcntl.LOCK_EX)
-
-  def __exit__(self, type, value, traceback):
-    fcntl.flock(self._fd, fcntl.LOCK_UN)
-    os.close(self._fd)
-
-
 class Forwarder(object):
   """Thread-safe class to manage port forwards from the device to the host."""
 
@@ -53,18 +28,28 @@
   _DEVICE_FORWARDER_PATH = (constants.TEST_EXECUTABLE_DIR +
                             '/forwarder/device_forwarder')
   _LD_LIBRARY_PATH = 'LD_LIBRARY_PATH=%s' % _DEVICE_FORWARDER_FOLDER
-  _LOCK_PATH = '/tmp/chrome.forwarder.lock'
-  _MULTIPROCESSING_ENV_VAR = 'CHROME_FORWARDER_USE_MULTIPROCESSING'
 
-  _instance = None
+  def __init__(self, adb, build_type):
+    """Forwards TCP ports on the device back to the host.
 
-  @staticmethod
-  def UseMultiprocessing():
-    """Tells the forwarder that multiprocessing is used."""
-    os.environ[Forwarder._MULTIPROCESSING_ENV_VAR] = '1'
+    Works like adb forward, but in reverse.
 
-  @staticmethod
-  def Map(port_pairs, adb, build_type='Debug', tool=None):
+    Args:
+      adb: Instance of AndroidCommands for talking to the device.
+      build_type: 'Release' or 'Debug'.
+    """
+    assert build_type in ('Release', 'Debug')
+    self._adb = adb
+    self._device_to_host_port_map = dict()
+    self._host_to_device_port_map = dict()
+    self._device_initialized = False
+    self._host_adb_control_port = 0
+    self._lock = threading.Lock()
+    self._host_forwarder_path = _MakeBinaryPath(build_type, 'host_forwarder')
+    self._device_forwarder_path_on_host = os.path.join(
+        cmd_helper.OutDirectory.get(), build_type, 'forwarder_dist')
+
+  def Run(self, port_pairs, tool):
     """Runs the forwarder.
 
     Args:
@@ -73,29 +58,24 @@
                  port will by dynamically assigned on the device. You can
                  get the number of the assigned port using the
                  DevicePortForHostPort method.
-      adb: An AndroidCommands instance.
       tool: Tool class to use to get wrapper, if necessary, for executing the
             forwarder (see valgrind_tools.py).
 
     Raises:
       Exception on failure to forward the port.
     """
-    if not tool:
-      tool = valgrind_tools.CreateTool(None, adb)
-    with _FileLock(Forwarder._LOCK_PATH):
-      instance = Forwarder._GetInstanceLocked(build_type, tool)
-      instance._InitDeviceLocked(adb, tool)
-
-      device_serial = adb.Adb().GetSerialNumber()
+    with self._lock:
+      self._InitDeviceLocked(tool)
+      host_name = '127.0.0.1'
       redirection_commands = [
-          ['--serial-id=' + device_serial, '--map', str(device),
-           str(host)] for device, host in port_pairs]
+          ['--serial-id=' + self._adb.Adb().GetSerialNumber(), '--map',
+           str(device), str(host)] for device, host in port_pairs]
       logging.info('Forwarding using commands: %s', redirection_commands)
 
       for redirection_command in redirection_commands:
         try:
           (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
-              [instance._host_forwarder_path] + redirection_command)
+              [self._host_forwarder_path] + redirection_command)
         except OSError as e:
           if e.errno == 2:
             raise Exception('Unable to start host forwarder. Make sure you have'
@@ -103,203 +83,83 @@
           else: raise
         if exit_code != 0:
           raise Exception('%s exited with %d:\n%s' % (
-              instance._host_forwarder_path, exit_code, '\n'.join(output)))
+              self._host_forwarder_path, exit_code, '\n'.join(output)))
         tokens = output.split(':')
         if len(tokens) != 2:
           raise Exception(('Unexpected host forwarder output "%s", ' +
                           'expected "device_port:host_port"') % output)
         device_port = int(tokens[0])
         host_port = int(tokens[1])
-        serial_with_port = (device_serial, device_port)
-        instance._device_to_host_port_map[serial_with_port] = host_port
-        instance._host_to_device_port_map[host_port] = serial_with_port
+        self._device_to_host_port_map[device_port] = host_port
+        self._host_to_device_port_map[host_port] = device_port
         logging.info('Forwarding device port: %d to host port: %d.',
                      device_port, host_port)
 
-  @staticmethod
-  def UnmapDevicePort(device_port, adb):
+  def _InitDeviceLocked(self, tool):
+    """Initializes the device forwarder process (only once)."""
+    if self._device_initialized:
+      return
+    self._adb.PushIfNeeded(
+        self._device_forwarder_path_on_host,
+        Forwarder._DEVICE_FORWARDER_FOLDER)
+    (exit_code, output) = self._adb.GetShellCommandStatusAndOutput(
+        '%s %s %s' % (Forwarder._LD_LIBRARY_PATH, tool.GetUtilWrapper(),
+                      Forwarder._DEVICE_FORWARDER_PATH))
+    if exit_code != 0:
+      raise Exception(
+          'Failed to start device forwarder:\n%s' % '\n'.join(output))
+    self._device_initialized = True
+
+  def UnmapDevicePort(self, device_port):
     """Unmaps a previously forwarded device port.
 
     Args:
-      adb: An AndroidCommands instance.
-      device_port: A previously forwarded port (through Map()).
+      device_port: A previously forwarded port (through Run()).
     """
-    with _FileLock(Forwarder._LOCK_PATH):
-      Forwarder._UnmapDevicePortLocked(device_port, adb)
+    with self._lock:
+      self._UnmapDevicePortInternalLocked(device_port)
 
-  @staticmethod
-  def UnmapAllDevicePorts(adb):
-    """Unmaps all the previously forwarded ports for the provided device.
-
-    Args:
-      adb: An AndroidCommands instance.
-      port_pairs: A list of tuples (device_port, host_port) to unmap.
-    """
-    with _FileLock(Forwarder._LOCK_PATH):
-      port_map = Forwarder._GetInstanceLocked(
-          None, None)._device_to_host_port_map
-      adb_serial = adb.Adb().GetSerialNumber()
-      for ((device_serial, device_port), _) in port_map:
-        if adb_serial == device_serial:
-          Forwarder._UnmapDevicePortLocked(device_port, adb)
-
-  @staticmethod
-  def DevicePortForHostPort(host_port):
-    """Returns the device port that corresponds to a given host port."""
-    with _FileLock(Forwarder._LOCK_PATH):
-      (device_serial, device_port) = Forwarder._GetInstanceLocked(
-          None, None)._host_to_device_port_map.get(host_port)
-      return device_port
-
-  @staticmethod
-  def _GetInstanceLocked(build_type, tool):
-    """Returns the singleton instance.
-
-    Note that the global lock must be acquired before calling this method.
-
-    Args:
-      build_type: 'Release' or 'Debug'
-      tool: Tool class to use to get wrapper, if necessary, for executing the
-            forwarder (see valgrind_tools.py).
-    """
-    if not Forwarder._instance:
-      Forwarder._instance = Forwarder(build_type, tool)
-    return Forwarder._instance
-
-  def __init__(self, build_type, tool):
-    """Constructs a new instance of Forwarder.
-
-    Note that Forwarder is a singleton therefore this constructor should be
-    called only once.
-
-    Args:
-      build_type: 'Release' or 'Debug'
-      tool: Tool class to use to get wrapper, if necessary, for executing the
-            forwarder (see valgrind_tools.py).
-    """
-    assert not Forwarder._instance
-    self._build_type = build_type
-    self._tool = tool
-    self._initialized_devices = set()
-    self._device_to_host_port_map = dict()
-    self._host_to_device_port_map = dict()
-    self._host_forwarder_path = _MakeBinaryPath(
-        self._build_type, 'host_forwarder')
-    if not os.path.exists(self._host_forwarder_path):
-      self._build_type = 'Release' if self._build_type == 'Debug' else 'Debug'
-      self._host_forwarder_path = _MakeBinaryPath(
-          self._build_type, 'host_forwarder')
-      assert os.path.exists(
-          self._host_forwarder_path), 'Please build forwarder2'
-    self._device_forwarder_path_on_host = os.path.join(
-        cmd_helper.OutDirectory.get(), self._build_type, 'forwarder_dist')
-    self._InitHostLocked()
-
-  @staticmethod
-  def _UnmapDevicePortLocked(device_port, adb):
-    """Internal method used by UnmapDevicePort().
-
-    Note that the global lock must be acquired before calling this method.
-    """
-    instance = Forwarder._GetInstanceLocked(None, None)
-    serial = adb.Adb().GetSerialNumber()
-    serial_with_port = (serial, device_port)
-    if not serial_with_port in instance._device_to_host_port_map:
-      logging.error('Trying to unmap non-forwarded port %d' % device_port)
+  def _UnmapDevicePortInternalLocked(self, device_port):
+    if not device_port in self._device_to_host_port_map:
       return
-    redirection_command = ['--serial-id=' + serial, '--unmap', str(device_port)]
+    redirection_command = [
+        '--serial-id=' + self._adb.Adb().GetSerialNumber(), '--unmap',
+        str(device_port)]
     (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
-        [instance._host_forwarder_path] + redirection_command)
+        [self._host_forwarder_path] + redirection_command)
     if exit_code != 0:
       logging.error('%s exited with %d:\n%s' % (
-          instance._host_forwarder_path, exit_code, '\n'.join(output)))
-    host_port = instance._device_to_host_port_map[serial_with_port]
-    del instance._device_to_host_port_map[serial_with_port]
-    del instance._host_to_device_port_map[host_port]
+          self._host_forwarder_path, exit_code, '\n'.join(output)))
+    host_port = self._device_to_host_port_map[device_port]
+    del self._device_to_host_port_map[device_port]
+    del self._host_to_device_port_map[host_port]
 
   @staticmethod
-  def _GetPidForLock():
-    """Returns the PID used for host_forwarder initialization.
+  def KillHost(build_type='Debug'):
+    """Kills the forwarder process running on the host.
 
-    In case multi-process sharding is used, the PID of the "sharder" is used.
-    The "sharder" is the initial process that forks that is the parent process.
-    By default, multi-processing is not used. In that case the PID of the
-    current process is returned.
-    """
-    use_multiprocessing = Forwarder._MULTIPROCESSING_ENV_VAR in os.environ
-    return os.getppid() if use_multiprocessing else os.getpid()
-
-  def _InitHostLocked(self):
-    """Initializes the host forwarder daemon.
-
-    Note that the global lock must be acquired before calling this method. This
-    method kills any existing host_forwarder process that could be stale.
-    """
-    # See if the host_forwarder daemon was already initialized by a concurrent
-    # process or thread (in case multi-process sharding is not used).
-    pid_for_lock = Forwarder._GetPidForLock()
-    fd = os.open(Forwarder._LOCK_PATH, os.O_RDWR | os.O_CREAT)
-    with os.fdopen(fd, 'r+') as pid_file:
-      pid_with_start_time = pid_file.readline()
-      if pid_with_start_time:
-        (pid, process_start_time) = pid_with_start_time.split(':')
-        if pid == str(pid_for_lock):
-          if process_start_time == str(_GetProcessStartTime(pid_for_lock)):
-            return
-      self._KillHostLocked()
-      pid_file.seek(0)
-      pid_file.write(
-          '%s:%s' % (pid_for_lock, str(_GetProcessStartTime(pid_for_lock))))
-
-  def _InitDeviceLocked(self, adb, tool):
-    """Initializes the device_forwarder daemon for a specific device (once).
-
-    Note that the global lock must be acquired before calling this method. This
-    method kills any existing device_forwarder daemon on the device that could
-    be stale, pushes the latest version of the daemon (to the device) and starts
-    it.
-
     Args:
-      adb: An AndroidCommands instance.
-      tool: Tool class to use to get wrapper, if necessary, for executing the
-            forwarder (see valgrind_tools.py).
+      build_type: 'Release' or 'Debug' (default='Debug')
     """
-    device_serial = adb.Adb().GetSerialNumber()
-    if device_serial in self._initialized_devices:
-      return
-    Forwarder._KillDeviceLocked(adb, tool)
-    adb.PushIfNeeded(
-        self._device_forwarder_path_on_host,
-        Forwarder._DEVICE_FORWARDER_FOLDER)
-    (exit_code, output) = adb.GetShellCommandStatusAndOutput(
-        '%s %s %s' % (Forwarder._LD_LIBRARY_PATH, tool.GetUtilWrapper(),
-                      Forwarder._DEVICE_FORWARDER_PATH))
-    if exit_code != 0:
-      raise Exception(
-          'Failed to start device forwarder:\n%s' % '\n'.join(output))
-    self._initialized_devices.add(device_serial)
-
-  def _KillHostLocked(self):
-    """Kills the forwarder process running on the host.
-
-    Note that the global lock must be acquired before calling this method.
-    """
     logging.info('Killing host_forwarder.')
+    host_forwarder_path = _MakeBinaryPath(build_type, 'host_forwarder')
+    if not os.path.exists(host_forwarder_path):
+      host_forwarder_path = _MakeBinaryPath(
+          'Release' if build_type == 'Debug' else 'Debug', 'host_forwarder')
+    assert os.path.exists(host_forwarder_path), 'Please build forwarder2'
     (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
-        [self._host_forwarder_path, '--kill-server'])
+        [host_forwarder_path, '--kill-server'])
     if exit_code != 0:
       (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
-          ['pkill', '-9', 'host_forwarder'])
+          ['pkill', 'host_forwarder'])
       if exit_code != 0:
         raise Exception('%s exited with %d:\n%s' % (
-              self._host_forwarder_path, exit_code, '\n'.join(output)))
+              host_forwarder_path, exit_code, '\n'.join(output)))
 
   @staticmethod
-  def _KillDeviceLocked(adb, tool):
+  def KillDevice(adb, tool):
     """Kills the forwarder process running on the device.
 
-    Note that the global lock must be acquired before calling this method.
-
     Args:
       adb: Instance of AndroidCommands for talking to the device.
       tool: Wrapper tool (e.g. valgrind) that can be used to execute the device
@@ -320,3 +180,14 @@
       pids = adb.ExtractPid('device_forwarder')
       if pids:
         raise Exception('Timed out while killing device_forwarder')
+
+  def DevicePortForHostPort(self, host_port):
+    """Returns the device port that corresponds to a given host port."""
+    with self._lock:
+      return self._host_to_device_port_map.get(host_port)
+
+  def Close(self):
+    """Releases the previously forwarded ports."""
+    with self._lock:
+      for device_port in self._device_to_host_port_map.copy():
+        self._UnmapDevicePortInternalLocked(device_port)