pkg/private/manifest.py

# Copyright 2021 The Bazel Authors. All rights reserved.
#
# 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.

"""Common package builder manifest helpers
"""

import json


# These must be kept in sync with the declarations in private/pkg_files.bzl
ENTRY_IS_FILE = "file"  # Entry is a file: take content from <src>
ENTRY_IS_LINK = "symlink"  # Entry is a symlink: dest -> <src>
ENTRY_IS_DIR = "dir"  # Entry is an empty dir
ENTRY_IS_TREE = "tree" # Entry is a tree artifact: take tree from <src>
ENTRY_IS_EMPTY_FILE = "empty-file"  # Entry is a an empty file

class ManifestEntry(object):
    """Structured wrapper around rules_pkg-produced manifest entries"""
    type: str
    dest: str
    src: str
    mode: str
    user: str
    group: str
    uid: int
    gid: int
    origin: str = None

    def __init__(self, type, dest, src, mode, user, group, uid = None, gid = None, origin = None):
        self.type = type
        self.dest = dest
        self.src = src
        self.mode = mode
        self.user = user
        self.group = group
        self.uid = uid
        self.gid = gid
        self.origin = origin

    def __repr__(self):
        return "ManifestEntry<{}>".format(vars(self))

def read_entries_from(fh):
    """Return a list of ManifestEntry's from `fh`"""
    # Subtle: decode the content with read() rather than in json.load() because
    # the load in older python releases (< 3.7?) does not know how to decode.
    raw_entries = json.loads(fh.read())
    return [ManifestEntry(**entry) for entry in raw_entries]

def read_entries_from_file(manifest_path):
    """Return a list of ManifestEntry's from the manifest file at `path`"""
    with open(manifest_path, 'r', encoding='utf-8') as fh:
        return read_entries_from(fh)

def entry_type_to_string(et):
    """Entry type stringifier"""
    if et == ENTRY_IS_FILE:
        return "file"
    elif et == ENTRY_IS_LINK:
        return "symlink",
    elif et == ENTRY_IS_DIR:
        return "directory"
    elif et == ENTRY_IS_TREE:
        return "tree"
    elif et == ENTRY_IS_EMPTY_FILE:
        return "empty_file"
    else:
        raise ValueError("Invalid entry id {}".format(et))