distro.py: add $repo.db parsing

distro.py

@@ -1,4 +1,10 @@
 from copy import deepcopy
+import urllib.request
+import tempfile
+import os
+import tarfile
+import logging
+
 from constants import ARCHES, BASE_DISTROS, REPOSITORIES, KUPFER_HTTPS
 from config import config
 
@@ -28,6 +34,18 @@ class PackageInfo:
         self.filename = filename
         self.resolved_url = resolved_url
 
+    def __repr__(self):
+        return f'{self.name}@{self.version}'
+
+    def parse_desc(desc_str: str, resolved_url=None):
+        """Parses a desc file, returning a PackageInfo"""
+
+        pruned_lines = ([line.strip() for line in desc_str.split('%') if line.strip()])
+        desc = {}
+        for key, value in zip(pruned_lines[0::2], pruned_lines[1::2]):
+            desc[key.strip()] = value.strip()
+        return PackageInfo(desc['NAME'], desc['VERSION'], desc['FILENAME'], resolved_url=resolved_url)
+
 
 class RepoInfo:
     options: dict[str, str] = {}
@@ -49,10 +67,29 @@ class Repo(RepoInfo):
     def scan(self):
         self.resolved_url = resolve_url(self.url_template, repo_name=self.name, arch=self.arch)
         self.remote = not self.resolved_url.startswith('file://')
-        # TODO
+        uri = f'{self.resolved_url}/{self.name}.db'
+        file_handle = None
+        path = ''
+        if self.remote:
+            logging.debug(f'Downloading repo file from {uri}')
+            with urllib.request.urlopen(uri) as request:
+                fd, path = tempfile.mkstemp()
+                with open(fd, 'wb') as writable:
+                    writable.write(request.read())
+        else:
+            path = uri.split('file://')[1]
+        logging.debug(f'Parsing repo file at {path}')
+        with tarfile.open(path) as index:
+            for node in index.getmembers():
+                if os.path.basename(node.name) == 'desc':
+                    logging.debug(f'Parsing desc file for {os.path.dirname(node.name)}')
+                    pkg = PackageInfo.parse_desc(index.extractfile(node).read().decode(), self.resolved_url)
+                    self.packages[pkg.name] = pkg
+
         self.scanned = True
 
     def __init__(self, name: str, url_template: str, arch: str, options={}, scan=True):
+        self.packages = {}
         self.name = name
         self.url_template = url_template
         self.arch = arch