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

build/android/pylib/cmd_helper.py

Index: build/android/pylib/cmd_helper.py
diff --git a/build/android/pylib/cmd_helper.py b/build/android/pylib/cmd_helper.py
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+++ b/build/android/pylib/cmd_helper.py
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+# Copyright (c) 2012 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.
+
+"""A wrapper for subprocess to make calling shell commands easier."""
+
+import logging
+import os
+import pipes
+import select
+import signal
+import string
+import StringIO
+import subprocess
+import time
+
+# fcntl is not available on Windows.
+try:
+  import fcntl
+except ImportError:
+  fcntl = None
+
+_SafeShellChars = frozenset(string.ascii_letters + string.digits + '@%_-+=:,./')
+
+def SingleQuote(s):
+  """Return an shell-escaped version of the string using single quotes.
+
+  Reliably quote a string which may contain unsafe characters (e.g. space,
+  quote, or other special characters such as '$').
+
+  The returned value can be used in a shell command line as one token that gets
+  to be interpreted literally.
+
+  Args:
+    s: The string to quote.
+
+  Return:
+    The string quoted using single quotes.
+  """
+  return pipes.quote(s)
+
+def DoubleQuote(s):
+  """Return an shell-escaped version of the string using double quotes.
+
+  Reliably quote a string which may contain unsafe characters (e.g. space
+  or quote characters), while retaining some shell features such as variable
+  interpolation.
+
+  The returned value can be used in a shell command line as one token that gets
+  to be further interpreted by the shell.
+
+  The set of characters that retain their special meaning may depend on the
+  shell implementation. This set usually includes: '$', '`', '\', '!', '*',
+  and '@'.
+
+  Args:
+    s: The string to quote.
+
+  Return:
+    The string quoted using double quotes.
+  """
+  if not s:
+    return '""'
+  elif all(c in _SafeShellChars for c in s):
+    return s
+  else:
+    return '"' + s.replace('"', '\\"') + '"'
+
+
+def Popen(args, stdout=None, stderr=None, shell=None, cwd=None, env=None):
+  return subprocess.Popen(
+      args=args, cwd=cwd, stdout=stdout, stderr=stderr,
+      shell=shell, close_fds=True, env=env,
+      preexec_fn=lambda: signal.signal(signal.SIGPIPE, signal.SIG_DFL))
+
+
+def Call(args, stdout=None, stderr=None, shell=None, cwd=None, env=None):
+  pipe = Popen(args, stdout=stdout, stderr=stderr, shell=shell, cwd=cwd,
+               env=env)
+  pipe.communicate()
+  return pipe.wait()
+
+
+def RunCmd(args, cwd=None):
+  """Opens a subprocess to execute a program and returns its return value.
+
+  Args:
+    args: A string or a sequence of program arguments. The program to execute is
+      the string or the first item in the args sequence.
+    cwd: If not None, the subprocess's current directory will be changed to
+      |cwd| before it's executed.
+
+  Returns:
+    Return code from the command execution.
+  """
+  logging.info(str(args) + ' ' + (cwd or ''))
+  return Call(args, cwd=cwd)
+
+
+def GetCmdOutput(args, cwd=None, shell=False):
+  """Open a subprocess to execute a program and returns its output.
+
+  Args:
+    args: A string or a sequence of program arguments. The program to execute is
+      the string or the first item in the args sequence.
+    cwd: If not None, the subprocess's current directory will be changed to
+      |cwd| before it's executed.
+    shell: Whether to execute args as a shell command.
+
+  Returns:
+    Captures and returns the command's stdout.
+    Prints the command's stderr to logger (which defaults to stdout).
+  """
+  (_, output) = GetCmdStatusAndOutput(args, cwd, shell)
+  return output
+
+
+def _ValidateAndLogCommand(args, cwd, shell):
+  if isinstance(args, basestring):
+    if not shell:
+      raise Exception('string args must be run with shell=True')
+  else:
+    if shell:
+      raise Exception('array args must be run with shell=False')
+    args = ' '.join(SingleQuote(c) for c in args)
+  if cwd is None:
+    cwd = ''
+  else:
+    cwd = ':' + cwd
+  logging.info('[host]%s> %s', cwd, args)
+  return args
+
+
+def GetCmdStatusAndOutput(args, cwd=None, shell=False):
+  """Executes a subprocess and returns its exit code and output.
+
+  Args:
+    args: A string or a sequence of program arguments. The program to execute is
+      the string or the first item in the args sequence.
+    cwd: If not None, the subprocess's current directory will be changed to
+      |cwd| before it's executed.
+    shell: Whether to execute args as a shell command. Must be True if args
+      is a string and False if args is a sequence.
+
+  Returns:
+    The 2-tuple (exit code, output).
+  """
+  _ValidateAndLogCommand(args, cwd, shell)
+  pipe = Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+               shell=shell, cwd=cwd)
+  stdout, stderr = pipe.communicate()
+
+  if stderr:
+    logging.critical(stderr)
+  if len(stdout) > 4096:
+    logging.debug('Truncated output:')
+  logging.debug(stdout[:4096])
+  return (pipe.returncode, stdout)
+
+
+class TimeoutError(Exception):
+  """Module-specific timeout exception."""
+  pass
+
+
+def _IterProcessStdout(process, timeout=None, buffer_size=4096,
+                       poll_interval=1):
+  assert fcntl, 'fcntl module is required'
+  try:
+    # Enable non-blocking reads from the child's stdout.
+    child_fd = process.stdout.fileno()
+    fl = fcntl.fcntl(child_fd, fcntl.F_GETFL)
+    fcntl.fcntl(child_fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
+
+    end_time = (time.time() + timeout) if timeout else None
+    while True:
+      if end_time and time.time() > end_time:
+        raise TimeoutError
+      read_fds, _, _ = select.select([child_fd], [], [], poll_interval)
+      if child_fd in read_fds:
+        data = os.read(child_fd, buffer_size)
+        if not data:
+          break
+        yield data
+      if process.poll() is not None:
+        break
+  finally:
+    try:
+      # Make sure the process doesn't stick around if we fail with an
+      # exception.
+      process.kill()
+    except OSError:
+      pass
+    process.wait()
+
+
+def GetCmdStatusAndOutputWithTimeout(args, timeout, cwd=None, shell=False,
+                                     logfile=None):
+  """Executes a subprocess with a timeout.
+
+  Args:
+    args: List of arguments to the program, the program to execute is the first
+      element.
+    timeout: the timeout in seconds or None to wait forever.
+    cwd: If not None, the subprocess's current directory will be changed to
+      |cwd| before it's executed.
+    shell: Whether to execute args as a shell command. Must be True if args
+      is a string and False if args is a sequence.
+    logfile: Optional file-like object that will receive output from the
+      command as it is running.
+
+  Returns:
+    The 2-tuple (exit code, output).
+  """
+  _ValidateAndLogCommand(args, cwd, shell)
+  output = StringIO.StringIO()
+  process = Popen(args, cwd=cwd, shell=shell, stdout=subprocess.PIPE,
+                  stderr=subprocess.STDOUT)
+  for data in _IterProcessStdout(process, timeout=timeout):
+    if logfile:
+      logfile.write(data)
+    output.write(data)
+  return process.returncode, output.getvalue()
+
+
+def IterCmdOutputLines(args, timeout=None, cwd=None, shell=False,
+                       check_status=True):
+  """Executes a subprocess and continuously yields lines from its output.
+
+  Args:
+    args: List of arguments to the program, the program to execute is the first
+      element.
+    cwd: If not None, the subprocess's current directory will be changed to
+      |cwd| before it's executed.
+    shell: Whether to execute args as a shell command. Must be True if args
+      is a string and False if args is a sequence.
+    check_status: A boolean indicating whether to check the exit status of the
+      process after all output has been read.
+
+  Yields:
+    The output of the subprocess, line by line.
+
+  Raises:
+    CalledProcessError if check_status is True and the process exited with a
+      non-zero exit status.
+  """
+  cmd = _ValidateAndLogCommand(args, cwd, shell)
+  process = Popen(args, cwd=cwd, shell=shell, stdout=subprocess.PIPE,
+                  stderr=subprocess.STDOUT)
+  buffer_output = ''
+  for data in _IterProcessStdout(process, timeout=timeout):
+    buffer_output += data
+    has_incomplete_line = buffer_output[-1] not in '\r\n'
+    lines = buffer_output.splitlines()
+    buffer_output = lines.pop() if has_incomplete_line else ''
+    for line in lines:
+      yield line
+  if buffer_output:
+    yield buffer_output
+  if check_status and process.returncode:
+    raise subprocess.CalledProcessError(process.returncode, cmd)