+
−# Copyright 2009 the Melange authors.
+
−#
+
−# Licensed under the Apache License, Version 2.0 (the "License");
+
−# you may not use this file except in compliance with the License.
+
−# You may obtain a copy of the License at
+
−#
+
−#   http://www.apache.org/licenses/LICENSE-2.0
+
−#
+
−# Unless required by applicable law or agreed to in writing, software
+
−# distributed under the License is distributed on an "AS IS" BASIS,
+
−# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+
−# See the License for the specific language governing permissions and
+
−# limitations under the License.
+
−
+
−"""Various utilities.
+
−
+
−Current contents:
+
− - Text colorization using ANSI color codes
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− - A class to construct and manage paths under a root path.
+
− - A helper to manage running subprocesses, wrapping the subprocess module.
+
−"""
+
−
+
−__authors__ = [
+
−    # alphabetical order by last name, please
+
−    '"David Anderson" <dave@natulte.net>',
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−    ]
+
−
+
−import os.path
+
−import re
+
−import subprocess
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−
+
−import error
+
−
+
−
+
−class Error(error.Error):
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−    pass
+
−
+
−
+
−class SubprocessFailed(Error):
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−    """A subprocess returned a non-zero error code."""
+
−
+
−
+
−# The magic escape sequence understood by modern terminal emulators to
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−# configure fore/background colors and other basic text display
+
−# settings.
+
−_ANSI_ESCAPE = '\x1b[%dm'
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−_ANSI_ESCAPE_RE = re.compile(r'\x1b\[\d+m')
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−
+
−
+
−# Some internal non-color settings that we use.
+
−_RESET = 0  # Reset to terminal defaults.
+
−_BOLD = 1   # Brighter colors.
+
−
+
−
+
−# ANSI color codes.
+
−RED = 31
+
−GREEN = 32
+
−WHITE = 37
+
−
+
−
+
−def _ansi_escape(code):
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−    return _ANSI_ESCAPE % code
+
−
+
−
+
−def colorize(text, color, bold=False):
+
−    """Colorize some text using ANSI color codes.
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−
+
−    Note that while ANSI color codes look good in a terminal they look
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−    like noise in log files unless viewed in an ANSI color capable
+
−    viewer (such as 'less -R').
+
−
+
−    Args:
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−      text: The text to colorize.
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−      color: One of the color symbols from this module.
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−      bold: If True, make the color brighter.
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−
+
−    Returns:
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−      The input text string, appropriately sprinkled with color
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−      codes. Colors are reset to terminal defaults after the input
+
−      text.
+
−    """
+
−    bold = _ansi_escape(_BOLD) if bold else ''
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−    return '%s%s%s%s' % (bold, _ansi_escape(color),
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−                         text, _ansi_escape(_RESET))
+
−
+
−
+
−def decolorize(text):
+
−    """Remove ANSI color codes from text."""
+
−    return _ANSI_ESCAPE_RE.sub('', text)
+
−
+
−
+
−class Paths(object):
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−    """A helper to construct and check paths under a given root."""
+
−
+
−    def __init__(self, root):
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−        """Initializer.
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−
+
−        Args:
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−          root: The root of all paths this instance will consider.
+
−        """
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−        self._root = os.path.abspath(
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−            os.path.expandvars(os.path.expanduser(root)))
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−
+
−    def path(self, path=''):
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−        """Construct and return a path under the path root.
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−
+
−        Args:
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−          path: The desired path string relative to the root.
+
−
+
−        Returns:
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−          The absolute path corresponding to the relative input path.
+
−        """
+
−        assert not os.path.isabs(path)
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−        return os.path.abspath(os.path.join(self._root, path))
+
−
+
−    def exists(self, path=''):
+
−        """Check for the existence of a path under the path root.
+
−
+
−        Does not discriminate on the path type (ie. it could be a
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−        directory, a file, a symbolic link...), just checks for the
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−        existence of the path.
+
−
+
−        Args:
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−          path: The path string relative to the root.
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−
+
−        Returns:
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−          True if the path exists, False otherwise.
+
−        """
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−        return os.path.exists(self.path(path))
+
−
+
−
+
−def run(argv, cwd=None, capture=False, split_capture=True, stdin=''):
+
−    """Run the given command and optionally return its output.
+
−
+
−    Note that if you set capture=True, the command's output is
+
−    buffered in memory. Output capture should only be used with
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−    commands that output small amounts of data. O(kB) is fine, O(MB)
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−    is starting to push it a little.
+
−
+
−    Args:
+
−      argv: A list containing the name of the program to run, followed
+
−            by its argument vector.
+
−      cwd: Run the program from this directory.
+
−      capture: If True, capture the program's stdout stream. If False,
+
−               stdout will output to sys.stdout.
+
−      split_capture: If True, return the captured output as a list of
+
−                     lines. Else, return as a single unaltered string.
+
−      stdin: The string to feed to the program's stdin stream.
+
−
+
−    Returns:
+
−      If capture is True, a string containing the combined
+
−      stdout/stderr output of the program. If capture is False,
+
−      nothing is returned.
+
−
+
−    Raises:
+
−      SubprocessFailed: The subprocess exited with a non-zero exit
+
−                        code.
+
−    """
+
−    print colorize('# ' + ' '.join(argv), WHITE, bold=True)
+
−
+
−    process = subprocess.Popen(argv,
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−                               shell=False,
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−                               cwd=cwd,
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−                               stdin=subprocess.PIPE,
+
−                               stdout=(subprocess.PIPE if capture else None),
+
−                               stderr=None)
+
−    output, _ = process.communicate(input=stdin)
+
−    if process.returncode != 0:
+
−        raise SubprocessFailed('Process %s failed with output: %s' %
+
−                               (argv[0], output))
+
−    if output is not None and split_capture:
+
−        return output.strip().split('\n')
+
−    else:
+
−        return output