'property factories' for easier type coercion in plugin results.

debexpo/plugins/api.py

@@ -29,7 +29,7 @@
 #   OTHER DEALINGS IN THE SOFTWARE.
 
 """
-Holds some helpful classes for plugins to use or extend.
+Holds some helpful classes and functions for plugins to extend or use.
 """
 
 __author__ = 'Jonny Lamb'
@@ -40,7 +40,9 @@ __all__ = ['importercmd',
            'test_result',
            'BasePlugin',
            'QAPlugin',
-           'PluginResult']
+           'PluginResult',
+           'bool_field',
+           'int_field']
 
 import os.path
 import logging
@@ -82,7 +84,45 @@ def test_result(cls):
     cls.test_result = True
     return cls
 
+#
+# Property factories for PluginResult subclasses
+#
+
+# FIXME: move this somewhere else
+# FIXME: some of that could be abstracted
+
+def bool_field(name):
+    """ Property exposing a string ('true' or 'false') as a bool. """
+    def fget(instance):
+        return True if instance[name] == 'true' else False
+
+    def fset(instance, value):
+        if not isinstance(value, bool):
+            raise ValueError('Expected bool')
+        instance[name] = 'true' if value else 'false'
+
+    def fdel(instance):
+        del instance[name]
+
+    return property(fget, fset, fdel,
+                    "Read-write property exposing a string ('true' or 'false')"
+                    " as a bool.")
+
+def int_field(name):
+    """ Property exposing a string as an int """
+    def fget(instance):
+        return int(instance[name])
+
+    def fset(instance, value):
+        if not isinstance(value, int):
+            raise ValueError('Expected int')
+        instance[name] = unicode(value)
+
+    def fdel(instance):
+        del instance[name]
 
+    return property(fget, fset, fdel,
+                    'Read-write property exposing a string as an int')
 #
 # Bases classes for plugins
 #

debexpo/plugins/native.py

@@ -55,9 +55,7 @@ class NativeTest(PluginResult):
     Result of the 'native' plugin for a package.
     """
 
-    @property
-    def is_native(self):
-        return self['native'] == 'true'
+    is_native = bool_field('native')
 
     def __str__(self):
         return 'Package is %s native' % ('' if self.is_native else 'not')
@@ -83,13 +81,14 @@ class NativePlugin(QAPlugin):
             # Most uploads will not be native, and especially on mentors, a native
             # package is almost probably in error.
             log.warning('Package is native')
-            result['native'] = 'true'
+
             result['severity'] = constants.PLUGIN_SEVERITY_WARNING
         else:
             log.debug('Package is not native')
-            result['native'] = 'false'
             result['severity'] = constants.PLUGIN_SEVERITY_INFO
 
+        result.native = is_native
+
 plugin = NativePlugin
 models = [
     NativeTest,