[PATCH] UBUNTU: download-signed: improve to support grub2 downloads

[Dimitri John Ledkov]

- drop unused imports
- drop unused assignments
- switch to argparse, thus gain -h/--help
- add optional positional argument 'signed_type', defaults to 'signed'
  but can be specified to 'uefi' for grub2 downloads
- add support to simply download the "current" version

This enables `./download-signed grub2 current grub2 uefi` to fetch
grub2 signed binaries without breaking any compatibility with any
other invocations of this script.

BugLink: https://bugs.launchpad.net/bugs/1876875
Signed-off-by: Dimitri John Ledkov <xnox at ubuntu.com>
---
 download-signed | 40 +++++++++++++++++++++++++++++-----------
 1 file changed, 29 insertions(+), 11 deletions(-)

diff --git a/download-signed b/download-signed
index bed284e..0793696 100755
--- a/download-signed
+++ b/download-signed
@@ -1,9 +1,9 @@
 #! /usr/bin/python3
 
 import hashlib
+import argparse
 import os
 import re
-import shutil
 import sys
 import tarfile
 from urllib import request
@@ -14,12 +14,28 @@ from urllib.parse import (
     )
 
 import apt
-from aptsources.distro import get_distro
 
 # package_name: package containing the objects we signed
 # package_version: package version containing the objects we signed
 # src_package: source package name in dists
-(package_name, package_version, src_package) = sys.argv[1:]
+# signed_type: 'signed' or 'uefi' schema in the url
+
+parser = argparse.ArgumentParser()
+parser.add_argument(
+    "package_name",
+    help="package containining the objects we signed")
+parser.add_argument(
+    "package_version",
+    help="package version containing the objects we signed, or 'current'")
+parser.add_argument(
+    "src_package",
+    help="source package name in dists")
+parser.add_argument(
+    "signed_type",
+    nargs='?',
+    default='signed',
+    help="subdirectory type in the url, 'signed' or 'uefi'")
+args = parser.parse_args()
 
 
 class SignedDownloader:
@@ -30,7 +46,7 @@ class SignedDownloader:
     identify the members and to validate them once downloaded.
     """
 
-    def __init__(self, package_name, package_version, src_package):
+    def __init__(self, package_name, package_version, src_package, signed_type='signed'):
         self.package_name = package_name
         self.package_version = package_version
         self.src_package = src_package
@@ -41,10 +57,13 @@ class SignedDownloader:
         cache = apt.Cache()
 
         self.package = None
-        for version in cache[package_name].versions:
-            if version.version == self.package_version:
-                self.package = version
-                break
+        if self.package_version == "current":
+            self.package = cache[package_name].candidate
+        else:
+            for version in cache[package_name].versions:
+                if version.version == self.package_version:
+                    self.package = version
+                    break
 
         if not self.package:
             raise KeyError("{0}: package version not found".format(self.package_name))
@@ -52,7 +71,7 @@ class SignedDownloader:
         origin = self.package.origins[0]
         pool_parsed = urlparse(self.package.uri)
         self.package_dir = "%s/%s/%s/%s-%s/%s/" % (
-            origin.archive, 'main', 'signed',
+            origin.archive, 'main', signed_type,
             self.src_package, self.package.architecture, self.package_version)
 
         # Prepare the master url stem and pull out any username/password.  If present
@@ -152,7 +171,6 @@ class SignedDownloader:
         if os.path.exists(tarball_filename):
             with tarfile.open(tarball_filename) as tarball:
                 for tarinfo in tarball:
-                    fullname = os.path.abspath(os.path.join(base, tarinfo.name))
                     if not filename.startswith(here):
                         print('download-signed: {0}: tarball member outside output directory'.format(member))
                         sys.exit(1)
@@ -161,5 +179,5 @@ class SignedDownloader:
                     tarball.extract(tarinfo, base)
 
 
-downloader = SignedDownloader(package_name, package_version, src_package)
+downloader = SignedDownloader(**vars(args))
 downloader.download('.')
-- 
2.25.1