[pitivi] Make registering formatters a bit more dynamic.

[Edward Hervey <edwardrv src gnome org>]

commit 4bd620b367be4aa8a9f403ff3c3b234651f04fd2
Author: Alessandro Decina <alessandro d gmail com>
Date:   Thu Jun 4 15:45:12 2009 +0200

    Make registering formatters a bit more dynamic.
    
    Add pitivi.format.register_formatter so i can register dummy formatters in unit
    tests.
---
 pitivi/formatters/format.py |   46 ++++++++++++++-----------------------------
 pitivi/project.py           |    4 ++-
 2 files changed, 18 insertions(+), 32 deletions(-)

diff --git a/pitivi/formatters/format.py b/pitivi/formatters/format.py
index 1a2d48c..3be2233 100644
--- a/pitivi/formatters/format.py
+++ b/pitivi/formatters/format.py
@@ -27,29 +27,7 @@ from gettext import gettext as _
 
 # FIXME : We need a registry of all available formatters
 
-def load_project(uri, formatter=None, missinguricallback=None):
-    """
-    Load the project from the given location.
-
-    If specified, use the given formatter.
-
-    @type uri: L{str}
-    @param uri: The location of the project. Needs to be an
-    absolute URI.
-    @type formatter: L{Formatter}
-    @param formatter: If specified, try loading the project with that
-    L{Formatter}. If not specified, will try all available L{Formatter}s.
-    @raise FormatterLoadError: If the location couldn't be properly loaded.
-    @param missinguricallback: A callback that will be used if some
-    files to load can't be found anymore. The callback shall call the
-    formatter's addMapping() method with the moved location.
-    @type missinguricallback: C{callable}
-    @return: The project. The caller needs to ensure the loading is
-    finished before using it. See the 'loaded' property and signal of
-    L{Project}.
-    @rtype: L{Project}.
-    """
-    raise NotImplementedError
+_formatters = []
 
 def save_project(project, uri, formatter=None, overwrite=False):
     """
@@ -90,7 +68,7 @@ def can_handle_location(uri):
     @rtype: L{bool}
     """
 
-    for klass, name, exts in list_formats():
+    for klass, name, exts in _formatters:
         if klass.canHandle(uri):
             return True
 
@@ -102,12 +80,7 @@ def list_formats():
     file formats, where name is a user-readable name, and extensions is a
     sequence of extensions for this format ('.' omitted).
     """
-    from pitivi.formatters.etree import ElementTreeFormatter
-    from pitivi.formatters.playlist import PlaylistFormatter
-    return [
-        (ElementTreeFormatter, _("PiTiVi Native (XML)"), ('xptv',)),
-        (PlaylistFormatter, _("Playlist format"), ('pls', ))
-        ]
+    return _formatters
 
 def get_formatter_for_uri(uri):
     """
@@ -117,6 +90,17 @@ def get_formatter_for_uri(uri):
     @param uri: The location of the project file
     @return: an instance of a Formatter, or None
     """
-    for klass, name, exts in list_formats():
+    for klass, name, exts in _formatters:
         if klass.canHandle(uri):
             return klass()
+
+def register_formatter(klass, name, extensions):
+    _formatters.append((klass, name, extensions))
+
+# register known formatters
+
+from pitivi.formatters.etree import ElementTreeFormatter
+from pitivi.formatters.playlist import PlaylistFormatter
+
+register_formatter(ElementTreeFormatter, _("PiTiVi Native (XML)"), ('xptv',))
+register_formatter(PlaylistFormatter, _("Playlist format"), ('pls', ))
diff --git a/pitivi/project.py b/pitivi/project.py
index c3a1b76..a7ad77c 100644
--- a/pitivi/project.py
+++ b/pitivi/project.py
@@ -39,7 +39,6 @@ from pitivi.settings import ExportSettings
 from pitivi.configure import APPNAME
 from pitivi.signalinterface import Signallable
 from pitivi.action import ViewAction
-from pitivi.formatters.format import save_project
 
 class ProjectError(Exception):
     """Project error"""
@@ -194,6 +193,9 @@ class Project(Signallable, Loggable):
         @raises ProjectSaveLoadError: If no uri was provided and none was set
         previously.
         """
+        # import here to break circular import
+        from pitivi.formatters.format import save_project
+
         self.log("saving...")
         location = location or self.uri