hgweb: refactor checks for granting and revoking user permissions

hgweb: refactor checks for granting and revoking user permissions

Provides an entry point for extensions implementing more complex
authorization schemes.

Original patch proposed by Markus Zapke-Gründemann.

--- a/mercurial/hgweb/common.py	Wed Apr 17 14:38:02 2013 -0500
+++ b/mercurial/hgweb/common.py	Mon Apr 15 18:57:04 2013 -0300
@@ -18,6 +18,15 @@
 HTTP_SERVER_ERROR = 500
 
 
+def ismember(ui, username, userlist):
+    """Check if username is a member of userlist.
+
+    If userlist has a single '*' member, all users are considered members.
+    Can be overriden by extensions to provide more complex authorization
+    schemes.
+    """
+    return userlist == ['*'] or username in userlist
+
 def checkauthz(hgweb, req, op):
     '''Check permission for operation based on request data (including
     authentication info). Return if op allowed, else raise an ErrorResponse
@@ -26,12 +35,11 @@
     user = req.env.get('REMOTE_USER')
 
     deny_read = hgweb.configlist('web', 'deny_read')
-    if deny_read and (not user or deny_read == ['*'] or user in deny_read):
+    if deny_read and (not user or ismember(hgweb.repo.ui, user, deny_read)):
         raise ErrorResponse(HTTP_UNAUTHORIZED, 'read not authorized')
 
     allow_read = hgweb.configlist('web', 'allow_read')
-    result = (not allow_read) or (allow_read == ['*'])
-    if not (result or user in allow_read):
+    if allow_read and (not ismember(hgweb.repo.ui, user, allow_read)):
         raise ErrorResponse(HTTP_UNAUTHORIZED, 'read not authorized')
 
     if op == 'pull' and not hgweb.allowpull:
@@ -51,12 +59,11 @@
         raise ErrorResponse(HTTP_FORBIDDEN, 'ssl required')
 
     deny = hgweb.configlist('web', 'deny_push')
-    if deny and (not user or deny == ['*'] or user in deny):
+    if deny and (not user or ismember(hgweb.repo.ui, user, deny)):
         raise ErrorResponse(HTTP_UNAUTHORIZED, 'push not authorized')
 
     allow = hgweb.configlist('web', 'allow_push')
-    result = allow and (allow == ['*'] or user in allow)
-    if not result:
+    if not (allow and ismember(hgweb.repo.ui, user, allow)):
         raise ErrorResponse(HTTP_UNAUTHORIZED, 'push not authorized')
 
 # Hooks for hgweb permission checks; extensions can add hooks here.

--- a/mercurial/hgweb/hgwebdir_mod.py	Wed Apr 17 14:38:02 2013 -0500
+++ b/mercurial/hgweb/hgwebdir_mod.py	Mon Apr 15 18:57:04 2013 -0300
@@ -10,7 +10,7 @@
 from mercurial.i18n import _
 from mercurial import ui, hg, scmutil, util, templater
 from mercurial import error, encoding
-from common import ErrorResponse, get_mtime, staticfile, paritygen, \
+from common import ErrorResponse, get_mtime, staticfile, paritygen, ismember, \
                    get_contact, HTTP_OK, HTTP_NOT_FOUND, HTTP_SERVER_ERROR
 from hgweb_mod import hgweb, makebreadcrumb
 from request import wsgirequest
@@ -164,12 +164,12 @@
         user = req.env.get('REMOTE_USER')
 
         deny_read = ui.configlist('web', 'deny_read', untrusted=True)
-        if deny_read and (not user or deny_read == ['*'] or user in deny_read):
+        if deny_read and (not user or ismember(ui, user, deny_read)):
             return False
 
         allow_read = ui.configlist('web', 'allow_read', untrusted=True)
         # by default, allow reading if no allow_read option has been set
-        if (not allow_read) or (allow_read == ['*']) or (user in allow_read):
+        if (not allow_read) or ismember(ui, user, allow_read):
             return True
 
         return False