* fix: workaround bsddb3 idiocies, make read-only mode really work

pisi/context.py

@@ -46,15 +46,17 @@ import bsddb3.db as db
 
 def txn_proc(proc, txn = None):
     # can be used to txn protect a method automatically
-    assert dbenv
     if not txn:
-        autotxn = dbenv.txn_begin()
-        try:
-            retval = proc(autotxn)
-        except db.DBError, e:
-            autotxn.abort()
-            raise e
-        autotxn.commit()
+        if dbenv:
+            autotxn = dbenv.txn_begin()
+            try:
+                retval = proc(autotxn)
+            except db.DBError, e:
+                autotxn.abort()
+                raise e
+            autotxn.commit()
+        else:
+            retval = proc(None)
         return retval
     else:
         return proc(txn)

pisi/dbshelve.py

@@ -43,7 +43,11 @@ class DBShelf:
     """
     def __init__(self, dbenv = None):
         self.dbenv = dbenv
-        self.db = dbobj.DB(dbenv)
+        # how lame is bsddb3?
+        if self.dbenv:
+            self.db = dbobj.DB(dbenv)
+        else:
+            self.db = db.DB(None)
         self.binary = 1
 
     # it is better to explicitly close a shelf
@@ -68,7 +72,7 @@ class DBShelf:
                     raise e
                 autotxn.commit()
             else: # execute without transactions
-                proc(None)
+                retval = proc(None)
             return retval
         else:
             return proc(txn)
@@ -102,13 +106,13 @@ class DBShelf:
         def proc(txn):
             data = self.db.get(key)
             return cPickle.loads(data)
-        return self.txn_proc(proc, txn)
+        return self.txn_proc(proc, None)
 
     def __setitem__(self, key, value):
         # hyperdandik transactions
         def proc(txn):
             self.db.put(key,data,txn)
-        return self.txn_proc(proc, txn)
+        return self.txn_proc(proc, None)
 
     def __delitem__(self, key):
         txn = self.dbenv.txn_begin()

pisi/lockeddbshelve.py

@@ -65,6 +65,7 @@ def init_dbenv():
                   db.DB_CREATE)           # allow db to create files
         ctx.dbenv.open(pisi.context.config.db_dir(), flags)
     else:
+        ctx.ui.warning(_('Opening PİSİ database in read-only mode. Operations that require write access will fail.'))
         ctx.dbenv = None
 
 #def open(filename, flags='r', mode = 0644, filetype = db.DB_BTREE):
@@ -112,9 +113,9 @@ class LockedDBShelf(shelve.DBShelf):
                 flags = db.DB_TRUNCATE | db.DB_CREATE
             else:
                 raise Error, _("Flags should be one of 'r', 'w', 'c' or 'n' or use the bsddb.db.DB_* flags")
-        flags |= db.DB_AUTO_COMMIT
         self.flags = flags
         if self.flags & db.DB_RDONLY == 0:
+            flags |= db.DB_AUTO_COMMIT # use txn subsystem in write mode
             self.lock()
         filename = os.path.realpath(filename) # we give absolute path due to dbenv
         #print 'opening', filename, filetype, flags, mode