- fix import/export regression test for anydbm for latest journal fix

[roundup.git] / roundup / backends / __init__.py

diff --git a/roundup/backends/__init__.py b/roundup/backends/__init__.py
index d4efcf73b9ff49e7af9672ea228d80d071a99744..1fc794888400e87c30a1df4ad50dd61ac872ef0e 100644 (file)
--- a/roundup/backends/__init__.py
+++ b/roundup/backends/__init__.py
@@ -14,72 +14,75 @@
 # FOR A PARTICULAR PURPOSE.  THE CODE PROVIDED HEREUNDER IS ON AN "AS IS"
 # BASIS, AND THERE IS NO OBLIGATION WHATSOEVER TO PROVIDE MAINTENANCE,
 # SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
-# 
-# $Id: __init__.py,v 1.18 2002-09-23 12:02:53 richard Exp $
+#
+# $Id: __init__.py,v 1.40 2007-11-07 20:47:12 richard Exp $
+
+'''Container for the hyperdb storage backend implementations.
+'''
+__docformat__ = 'restructuredtext'
 
-__all__ = []
+import sys
 
-try:
-    import sys, anydbm
-    if not hasattr(sys, 'version_info') or sys.version_info < (2,1,2):
-        import dumbdbm
-        # dumbdbm only works in python 2.1.2+
-        assert anydbm._defaultmod != dumbdbm
-        del anydbm
-        del dumbdbm
-except AssertionError:
-    print "WARNING: you should upgrade to python 2.1.3"
-except ImportError, message:
-    if str(message) != 'No module named anydbm': raise
-else:
-    import back_anydbm
-    anydbm = back_anydbm
-    __all__.append('anydbm')
+# These names are used to suppress import errors.
+# If get_backend raises an ImportError with appropriate
+# module name, have_backend quietly returns False.
+# Otherwise the error is reraised.
+_modules = {
+    'mysql': ('MySQLdb',),
+    'postgresql': ('psycopg',),
+    'tsearch2': ('psycopg',),
+    'sqlite': ('pysqlite', 'pysqlite2', 'sqlite3', '_sqlite3', 'sqlite'),
+}
 
-try:
-    import gadfly
-    import gadfly.client
-except ImportError, message:
-    if str(message) != 'No module named gadfly': raise
-else:
-    import back_gadfly
-    gadfly = back_gadfly
-    __all__.append('gadfly')
+def get_backend(name):
+    '''Get a specific backend by name.'''
+    vars = globals()
+    # if requested backend has been imported yet, return current instance
+    if name in vars:
+        return vars[name]
+    # import the backend module
+    module_name = 'back_%s' % name
+    try:
+        module = __import__(module_name, vars)
+    except:
+        # import failed, but in versions prior to 2.4, a (broken)
+        # module is left in sys.modules and package globals;
+        # subsequent imports would succeed and get the broken module.
+        # This no longer happens in Python 2.4 and later.
+        if sys.version_info < (2, 4):
+            del sys.modules['.'.join((__name__, module_name))]
+            del vars[module_name]
+        raise
+    else:
+        vars[name] = module
+        return module
 
-try:
-    import sqlite
-except ImportError, message:
-    if str(message) != 'No module named sqlite': raise
-else:
-    import back_sqlite
-    sqlite = back_sqlite
-    __all__.append('sqlite')
+def have_backend(name):
+    '''Is backend "name" available?'''
+    if name == 'tsearch2':
+        # currently not working
+        return 0
+    try:
+        get_backend(name)
+        return 1
+    except ImportError, e:
+        for name in _modules.get(name, (name,)):
+            if str(e).startswith('No module named %s'%name):
+                return 0
+        raise
+    return 0
 
-try:
-    import bsddb
-except ImportError, message:
-    if str(message) != 'No module named bsddb': raise
-else:
-    import back_bsddb
-    bsddb = back_bsddb
-    __all__.append('bsddb')
+def list_backends():
+    '''List all available backend names.
 
-try:
-    import bsddb3
-except ImportError, message:
-    if str(message) != 'No module named bsddb3': raise
-else:
-    import back_bsddb3
-    bsddb3 = back_bsddb3
-    __all__.append('bsddb3')
+    This function has side-effect of registering backward-compatible
+    globals for all available backends.
 
-try:
-    import metakit
-except ImportError, message:
-    if str(message) != 'No module named metakit': raise
-else:
-    import back_metakit
-    metakit = back_metakit
-    __all__.append('metakit')
+    '''
+    l = []
+    for name in 'anydbm', 'mysql', 'sqlite', 'postgresql':
+        if have_backend(name):
+            l.append(name)
+    return l
 
-# vim: set filetype=python ts=4 sw=4 et si
+# vim: set filetype=python sts=4 sw=4 et si :