blender-archive/build_files/buildbot/codesign/archive_with_indicator.py

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#
#  This program is free software; you can redistribute it and/or
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#  as published by the Free Software Foundation; either version 2
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#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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# ##### END GPL LICENSE BLOCK #####

# <pep8 compliant>

import os
from pathlib import Path

import codesign.util as util


class ArchiveWithIndicator:
    """
    The idea of this class is to wrap around logic which takes care of keeping
    track of a name of an archive and synchronization routines between buildbot
    worker and signing server.

    The synchronization is done based on creating a special file after the
    archive file is knowingly ready for access.
    """

    # Base directory where the archive is stored (basically, a basename() of
    # the absolute archive file name).
    #
    # For example, 'X:\\TEMP\\'.
    base_dir: Path

    # Absolute file name of the archive.
    #
    # For example, 'X:\\TEMP\\FOO.ZIP'.
    archive_filepath: Path

    # Absolute name of a file which acts as an indication of the fact that the
    # archive is ready and is available for access.
    #
    # This is how synchronization between buildbot worker and signing server is
    # done:
    # - First, the archive is created under archive_filepath name.
    # - Second, the indication file is created under ready_indicator_filepath
    #   name.
    # - Third, the colleague of whoever created the indicator name watches for
    #   the indication file to appear, and once it's there it access the
    #   archive.
    ready_indicator_filepath: Path

    def __init__(
            self, base_dir: Path, archive_name: str, ready_indicator_name: str):
        """
        Construct the object from given base directory and name of the archive
        file:
          ArchiveWithIndicator(Path('X:\\TEMP'), 'FOO.ZIP', 'INPUT_READY')
        """

        self.base_dir = base_dir
        self.archive_filepath = self.base_dir / archive_name
        self.ready_indicator_filepath = self.base_dir / ready_indicator_name

    def is_ready(self) -> bool:
        """Check whether the archive is ready for access."""
        return self.ready_indicator_filepath.exists()

    def tag_ready(self) -> None:
        """
        Tag the archive as ready by creating the corresponding indication file.

        NOTE: It is expected that the archive was never tagged as ready before
              and that there are no subsequent tags of the same archive.
              If it is violated, an assert will fail.
        """
        assert not self.is_ready()
        # Try the best to make sure everything is synced to the file system,
        # to avoid any possibility of stamp appearing on a network share prior to
        # an actual file.
        if util.get_current_platform() != util.Platform.WINDOWS:
            os.sync()
        self.ready_indicator_filepath.touch()

    def clean(self) -> None:
        """
        Remove both archive and the ready indication file.
        """
        util.ensure_file_does_not_exist_or_die(self.ready_indicator_filepath)
        util.ensure_file_does_not_exist_or_die(self.archive_filepath)

    def is_fully_absent(self) -> bool:
        """
        Check whether both archive and its ready indicator are absent.
        Is used for a sanity check during code signing process by both
        buildbot worker and signing server.
        """
        return (not self.archive_filepath.exists() and
                not self.ready_indicator_filepath.exists())