recipe_modules/minfs/api.py

# Copyright 2016 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

from recipe_engine import recipe_api


class MinfsApi(recipe_api.RecipeApi):
  """MinfsApi provides support for Fuchia's MinFS tool.

    Currently this module can only be used with a Zircon build, which produces
    the local minfs binary.
    """

  def __init__(self, *args, **kwargs):
    super(MinfsApi, self).__init__(*args, **kwargs)
    # The path to the minfs command.
    self._minfs = None

  def __call__(self, *args, **kwargs):
    assert self._minfs
    name = kwargs.pop('name', 'minfs ' + args[1])
    cmd = [self._minfs]
    return self.m.step(name, cmd + list(args), **kwargs)

  @property
  def minfs_path(self):
    """The path to the minfs command."""
    return self._minfs

  @minfs_path.setter
  def minfs_path(self, path):
    """The path to the minfs command."""
    self._minfs = path

  def cp(self, from_path, to_path, image, **kwargs):
    """
        Copies a file or directory from an image.

        Paths inside of the MinFS image are prefixed with '::', so '::'
        refers to the root of the MinFS image.

        Args:
          from_path (str or Path): The path to copy from.
          to_path (str or Path): The path to copy to.
          image (str or Path): The path to the MinFS image.

        Returns:
          A step to perform the copy.
        """
    cmd = [
        image,
        'cp',
        from_path,
        to_path,
    ]

    return self(*cmd, **kwargs)

  def create(self, path, size='100M', **kwargs):
    """
        Creates a MinFS image at the given path.

        Args:
          path (str): The path at which to create the image.
          size (str): The size of the image, number followed by unit. Defaults to 100M.

        Returns:
          A step to perform the creation.
        """
    return self(str(path) + '@' + size, 'create', **kwargs)

  def copy_image(self, step_name, image_path, out_dir):
    """
        Copies everything from a minfs image into a local directory.

        Args:
          step_name (str): The name of the step under which to copy the minfs files.
          image_path (Path): Full path to the minfs image.
          out_dir (Path): Full path to the directory to copy files into.

        Returns:
          A step to perform the copy.
        """
    return self.cp(
        # Paths inside of the MinFS image are prefixed with '::', so '::'
        # refers to the root of the MinFS image.
        '::',
        out_dir,
        image_path,
        name=step_name,
    )