- 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 4bffc9409814d62db6ed831b7f06e263442208f3..1fc794888400e87c30a1df4ad50dd61ac872ef0e 100644 (file)
--- a/roundup/backends/__init__.py
+++ b/roundup/backends/__init__.py
@@ -1,4 +1,88 @@
-import _bsddb; bsddb = _bsddb
-import _anydbm; anydbm = _anydbm
+#
+# Copyright (c) 2001 Bizar Software Pty Ltd (http://www.bizarsoftware.com.au/)
+# This module is free software, and you may redistribute it and/or modify
+# under the same terms as Python, so long as this copyright message and
+# disclaimer are retained in their original form.
+#
+# IN NO EVENT SHALL BIZAR SOFTWARE PTY LTD BE LIABLE TO ANY PARTY FOR
+# DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING
+# OUT OF THE USE OF THIS CODE, EVEN IF THE AUTHOR HAS BEEN ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+# BIZAR SOFTWARE PTY LTD SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+# BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# 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 1.40 2007-11-07 20:47:12 richard Exp $
 
-__all__ = ['bsddb', 'anydbm']
+'''Container for the hyperdb storage backend implementations.
+'''
+__docformat__ = 'restructuredtext'
+
+import sys
+
+# 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'),
+}
+
+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
+
+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
+
+def list_backends():
+    '''List all available backend names.
+
+    This function has side-effect of registering backward-compatible
+    globals for all available backends.
+
+    '''
+    l = []
+    for name in 'anydbm', 'mysql', 'sqlite', 'postgresql':
+        if have_backend(name):
+            l.append(name)
+    return l
+
+# vim: set filetype=python sts=4 sw=4 et si :