Split pkg_zip implementation out of pkg.bzl (#461)

* Decouple zip implementation from pkg.bzl.

1 files changed, 132 insertions, 0 deletions

diff --git a/pkg/private/zip/build_zip.py b/pkg/private/zip/build_zip.py
new file mode 100644
index 0000000..1b26a1b
--- /dev/null
+++ b/pkg/private/zip/build_zip.py
@@ -0,0 +1,132 @@
+# Copyright 2015 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.
+"""This tool builds zip files from a list of inputs."""
+
+import argparse
+import datetime
+import json
+import zipfile
+
+from pkg.private import build_info
+from pkg.private import helpers
+from pkg.private import manifest
+
+ZIP_EPOCH = 315532800
+
+# Unix dir bit and Windows dir bit. Magic from zip spec
+UNIX_DIR_BIT = 0o40000
+MSDOS_DIR_BIT = 0x10
+
+def _create_argument_parser():
+  """Creates the command line arg parser."""
+  parser = argparse.ArgumentParser(description='create a zip file',
+                                   fromfile_prefix_chars='@')
+  parser.add_argument('-o', '--output', type=str,
+                      help='The output zip file path.')
+  parser.add_argument(
+      '-d', '--directory', type=str, default='/',
+      help='An absolute path to use as a prefix for all files in the zip.')
+  parser.add_argument(
+      '-t', '--timestamp', type=int, default=ZIP_EPOCH,
+      help='The unix time to use for files added into the zip. values prior to'
+           ' Jan 1, 1980 are ignored.')
+  parser.add_argument('--stamp_from', default='',
+                      help='File to find BUILD_STAMP in')
+  parser.add_argument(
+      '-m', '--mode',
+      help='The file system mode to use for files added into the zip.')
+  parser.add_argument('--manifest',
+                      help='manifest of contents to add to the layer.')
+  parser.add_argument(
+      'files', type=str, nargs='*',
+      help='Files to be added to the zip, in the form of {srcpath}={dstpath}.')
+  return parser
+
+
+def _combine_paths(left, right):
+  result = left.rstrip('/') + '/' + right.lstrip('/')
+
+  # important: remove leading /'s: the zip format spec says paths should never
+  # have a leading slash, but Python will happily do this. The built-in zip
+  # tool in Windows will complain that such a zip file is invalid.
+  return result.lstrip('/')
+
+
+def parse_date(ts):
+  ts = datetime.datetime.utcfromtimestamp(ts)
+  return (ts.year, ts.month, ts.day, ts.hour, ts.minute, ts.second)
+
+def _add_manifest_entry(options, zip_file, entry, default_mode, ts):
+  """Add an entry to the zip file.
+
+  Args:
+    options: parsed options
+    zip_file: ZipFile to write to
+    entry: manifest entry
+    default_mode: (int) file mode to use if not specified in the entry.
+    ts: (int) time stamp to add to files
+  """
+
+  entry_type, dest, src, mode, user, group = entry
+
+  # Use the pkg_tar mode/owner remaping as a fallback
+  non_abs_path = dest.strip('/')
+  dst_path = _combine_paths(options.directory, non_abs_path)
+  if entry_type == manifest.ENTRY_IS_DIR and not dst_path.endswith('/'):
+    dst_path += '/'
+  entry_info = zipfile.ZipInfo(filename=dst_path, date_time=ts)
+  # See http://www.pkware.com/documents/casestudies/APPNOTE.TXT
+  # denotes UTF-8 encoded file name.
+  entry_info.flag_bits |= 0x800
+  if mode:
+    f_mode = int(mode, 8)
+  else:
+    f_mode = default_mode
+
+  # See: https://trac.edgewall.org/attachment/ticket/8919/ZipDownload.patch
+  # external_attr is 4 bytes in size. The high order two bytes represent UNIX
+  # permission and file type bits, while the low order two contain MS-DOS FAT file
+  # attributes.
+  entry_info.external_attr = f_mode << 16
+  if entry_type == manifest.ENTRY_IS_FILE:
+    entry_info.compress_type = zipfile.ZIP_DEFLATED
+    with open(src, 'rb') as src:
+      zip_file.writestr(entry_info, src.read())
+  elif entry_type == manifest.ENTRY_IS_DIR:
+    entry_info.compress_type = zipfile.ZIP_STORED
+    # Set directory bits
+    entry_info.external_attr |= (UNIX_DIR_BIT << 16) | MSDOS_DIR_BIT
+    zip_file.writestr(entry_info, '')
+  # TODO(#309): All the rest
+
+def main(args):
+  unix_ts = max(ZIP_EPOCH, args.timestamp)
+  if args.stamp_from:
+    unix_ts = build_info.get_timestamp(args.stamp_from)
+  ts = parse_date(unix_ts)
+  default_mode = None
+  if args.mode:
+    default_mode = int(args.mode, 8)
+
+  with zipfile.ZipFile(args.output, mode='w') as zip_file:
+    if args.manifest:
+      with open(args.manifest, 'r') as manifest_fp:
+        manifest = json.load(manifest_fp)
+        for entry in manifest:
+          _add_manifest_entry(args, zip_file, entry, default_mode, ts)
+
+
+if __name__ == '__main__':
+  arg_parser = _create_argument_parser()
+  main(arg_parser.parse_args())