Basic interface for generic data persistence.data-persistence

1 files changed, 43 insertions, 0 deletions

diff --git a/data.py b/data.py
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index 0000000..c598451
--- /dev/null
+++ b/data.py
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+
+class Data:
+    """Data is a generic storage interface for addons which need to persist data.
+
+    Addons can access Data through the Connection.data attribute. Each addon
+    should add its own attribute to Data to serve as a namespace. For example,
+    the Foo addon might store a dict as such:
+
+        Connection.data.foo = dict()
+
+    Data doesn't persist anything on its own but instead relies on a persistence
+    addon to handle the onDataSave and onDataLoad events.
+
+    Data fires an onDataLoaded event to inform addons that new data may be available.
+    """
+
+    def __init__(self, context, **kwargs):
+        """Create a Data for the given Connection context.
+
+        Optionally pass in a dict of values to load.
+        """
+        self.__dict__ = kwargs
+        self.context = context
+
+    def set_data(self, values):
+        """Replace all values in this Data with the given dict."""
+        contex = self.context
+        self.__dict__ = values
+        self.context = context
+        self.context.fireEvent([('onDataLoaded', dict(data=self), False)])
+
+    def merge(self, values):
+        """Merge a dictionary into this Data."""
+        for k, v, in values.iteritems():
+            setattr(self, k, v)
+        self.context.fireEvent([('onDataLoaded', dict(data=self), False)])
+
+    def save(self):
+        """Trigger the onDataSave event."""
+        data = self.__dict__
+        del data['context']
+        self.context.fireEvent([('onDataSave', dict(data=self, values=data), False)])
+