Add a snapshot of flutter/engine/src/build to our sdk

build/android/pylib/utils/reraiser_thread.py

+# Copyright 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Thread and ThreadGroup that reraise exceptions on the main thread."""
+# pylint: disable=W0212
+
+import logging
+import sys
+import threading
+import traceback
+
+from pylib.utils import watchdog_timer
+
+
+class TimeoutError(Exception):
+  """Module-specific timeout exception."""
+  pass
+
+
+def LogThreadStack(thread):
+  """Log the stack for the given thread.
+
+  Args:
+    thread: a threading.Thread instance.
+  """
+  stack = sys._current_frames()[thread.ident]
+  logging.critical('*' * 80)
+  logging.critical('Stack dump for thread %r', thread.name)
+  logging.critical('*' * 80)
+  for filename, lineno, name, line in traceback.extract_stack(stack):
+    logging.critical('File: "%s", line %d, in %s', filename, lineno, name)
+    if line:
+      logging.critical('  %s', line.strip())
+  logging.critical('*' * 80)
+
+
+class ReraiserThread(threading.Thread):
+  """Thread class that can reraise exceptions."""
+
+  def __init__(self, func, args=None, kwargs=None, name=None):
+    """Initialize thread.
+
+    Args:
+      func: callable to call on a new thread.
+      args: list of positional arguments for callable, defaults to empty.
+      kwargs: dictionary of keyword arguments for callable, defaults to empty.
+      name: thread name, defaults to Thread-N.
+    """
+    super(ReraiserThread, self).__init__(name=name)
+    if not args:
+      args = []
+    if not kwargs:
+      kwargs = {}
+    self.daemon = True
+    self._func = func
+    self._args = args
+    self._kwargs = kwargs
+    self._ret = None
+    self._exc_info = None
+
+  def ReraiseIfException(self):
+    """Reraise exception if an exception was raised in the thread."""
+    if self._exc_info:
+      raise self._exc_info[0], self._exc_info[1], self._exc_info[2]
+
+  def GetReturnValue(self):
+    """Reraise exception if present, otherwise get the return value."""
+    self.ReraiseIfException()
+    return self._ret
+
+  #override
+  def run(self):
+    """Overrides Thread.run() to add support for reraising exceptions."""
+    try:
+      self._ret = self._func(*self._args, **self._kwargs)
+    except: # pylint: disable=W0702
+      self._exc_info = sys.exc_info()
+
+
+class ReraiserThreadGroup(object):
+  """A group of ReraiserThread objects."""
+
+  def __init__(self, threads=None):
+    """Initialize thread group.
+
+    Args:
+      threads: a list of ReraiserThread objects; defaults to empty.
+    """
+    if not threads:
+      threads = []
+    self._threads = threads
+
+  def Add(self, thread):
+    """Add a thread to the group.
+
+    Args:
+      thread: a ReraiserThread object.
+    """
+    self._threads.append(thread)
+
+  def StartAll(self):
+    """Start all threads."""
+    for thread in self._threads:
+      thread.start()
+
+  def _JoinAll(self, watcher=None):
+    """Join all threads without stack dumps.
+
+    Reraises exceptions raised by the child threads and supports breaking
+    immediately on exceptions raised on the main thread.
+
+    Args:
+      watcher: Watchdog object providing timeout, by default waits forever.
+    """
+    if watcher is None:
+      watcher = watchdog_timer.WatchdogTimer(None)
+    alive_threads = self._threads[:]
+    while alive_threads:
+      for thread in alive_threads[:]:
+        if watcher.IsTimedOut():
+          raise TimeoutError('Timed out waiting for %d of %d threads.' %
+                             (len(alive_threads), len(self._threads)))
+        # Allow the main thread to periodically check for interrupts.
+        thread.join(0.1)
+        if not thread.isAlive():
+          alive_threads.remove(thread)
+    # All threads are allowed to complete before reraising exceptions.
+    for thread in self._threads:
+      thread.ReraiseIfException()
+
+  def JoinAll(self, watcher=None):
+    """Join all threads.
+
+    Reraises exceptions raised by the child threads and supports breaking
+    immediately on exceptions raised on the main thread. Unfinished threads'
+    stacks will be logged on watchdog timeout.
+
+    Args:
+      watcher: Watchdog object providing timeout, by default waits forever.
+    """
+    try:
+      self._JoinAll(watcher)
+    except TimeoutError:
+      for thread in (t for t in self._threads if t.isAlive()):
+        LogThreadStack(thread)
+      raise
+
+  def GetAllReturnValues(self, watcher=None):
+    """Get all return values, joining all threads if necessary.
+
+    Args:
+      watcher: same as in |JoinAll|. Only used if threads are alive.
+    """
+    if any([t.isAlive() for t in self._threads]):
+      self.JoinAll(watcher)
+    return [t.GetReturnValue() for t in self._threads]
+