[entropy.tools] introduce expand_plain_database_mirror()

This follows the previously introduced expand_plain_package_mirror()
method. Now both methods can expand repository and package mirror URLs
read from Entropy repository configuration files adding product, arch
and branch information.

lib/entropy/core/settings/base.py

@@ -1373,9 +1373,11 @@ class SystemSettings(Singleton, EntropyPluginStore):
                 raise AttributeError("invalid repository database URL")
         mydata['plain_database'] = repodatabase
 
-        mydata['database'] = repodatabase + os.path.sep + product + \
-            os.path.sep + reponame + "/database/" + etpConst['currentarch'] + \
-            os.path.sep + branch
+        database = entropy.tools.expand_plain_database_mirror(
+            repodatabase, product, reponame, branch)
+        if database is None:
+            database = const_convert_to_unicode("")
+        mydata['database'] = database
 
         mydata['notice_board'] = mydata['database'] + os.path.sep + \
             etpConst['rss-notice-board']
@@ -1419,9 +1421,6 @@ class SystemSettings(Singleton, EntropyPluginStore):
         repopackages = [x.strip() for x in repopackages.split() if x.strip()]
 
         for repo_package in repopackages:
-            if not entropy.tools.is_valid_uri(repo_package):
-                # filter out
-                continue
             new_repo_package = entropy.tools.expand_plain_package_mirror(
                 repo_package, product, reponame)
             if new_repo_package is None:

lib/entropy/tools.py

@@ -2490,16 +2490,34 @@ def expand_plain_package_mirror(mirror, product, repository_id):
     @type product: string
     @param repository_id: repository identifier
     @type repository_id: string
-    @return: expanded URL or None, if mirror url is invalid
+    @return: expanded URL or None if invalid
     @rtype: string or None
     """
     if not is_valid_uri(mirror):
         return None
-    try:
-        mirror = str(mirror)
-    except (UnicodeDecodeError, UnicodeEncodeError,):
+    sep = const_convert_to_unicode("/")
+    return mirror + sep + product + sep + repository_id
+
+def expand_plain_database_mirror(mirror, product, repository_id, branch):
+    """
+    Expand plain database mirror URL adding product, repository identifier
+    and branch data to it.
+
+    @param mirror: mirror URL
+    @type mirror: string
+    @param product: Entropy repository product
+    @type product: string
+    @param repository_id: repository identifier
+    @type repository_id: string
+    @return: expanded URL or None if invalid
+    @rtype: string or None
+    """
+    if not is_valid_uri(mirror):
         return None
-    return mirror + os.path.sep + product + os.path.sep + repository_id
+    sep = const_convert_to_unicode("/")
+    return mirror + sep + product + sep + repository_id + sep + \
+        etpConst['databaserelativepath_basedir'] + sep + \
+        etpConst['currentarch'] + sep + branch
 
 _repo_re = re.compile("^(([a-zA-Z]|[a-zA-Z][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z]|[A-Za-z][A-Za-z0-9\-]*[A-Za-z0-9])$", re.IGNORECASE)
 def validate_repository_id(repository_id):