wip.

o Changing the data sources to not implicitly starting as a union of all
  the input data sets.

1 files changed, 82 insertions, 32 deletions

diff --git a/src/ee/fact/__init__.py b/src/ee/fact/__init__.py
index 1bdef0d..02e6b2a 100644
--- a/src/ee/fact/__init__.py
+++ b/src/ee/fact/__init__.py
@@ -3,7 +3,7 @@ import logging
 import os
 from functools import total_ordering
 from pathlib import Path
-from typing import MutableMapping, Optional, Mapping, List
+from typing import MutableMapping, Optional, List, Tuple
 
 logger = logging.getLogger(__name__)
 
@@ -81,10 +81,9 @@ class Object(object):
 class DataSet(object):
     def __init__(self, name):
         self._name = name
-        self._object_types = {}
-        self._objects_by_type = {}  # type: MutableMapping[str, Mapping[str, Object]]
+        self._object_types = {}  # type: MutableMapping[str, ObjectType]
+        self._objects_by_type = {}  # type: MutableMapping[ObjectType, MutableMapping[str, Object]]
         self._frozen = False
-        self._changed = False
 
     @property
     def name(self):
@@ -93,38 +92,82 @@ class DataSet(object):
     def freeze(self):
         self._frozen = True
 
-    def get_object_type(self, object_type: str) -> ObjectType:
+    def _assert_not_frozen(self):
+        if self._frozen:
+            raise Exception("This data set is frozen")
+
+    def _check_object_type(self, object_type: str, create: bool) -> \
+            Optional[Tuple[ObjectType, MutableMapping[str, Object]]]:
         try:
-            return self._object_types[object_type]
+            ot = self._object_types[object_type]
+            objects = self._objects_by_type[ot]
+            return ot, objects,
         except KeyError:
+            if not create:
+                return None
+
+            self._assert_not_frozen()
+
             ot = ObjectType(object_type)
             self._object_types[object_type] = ot
-            self._changed = True
-            return ot
+            self._objects_by_type[ot] = objects = {}
+            return ot, objects,
 
-    def get_object(self, object_type: str, key: str) -> Object:
-        try:
-            objects = self._objects_by_type[object_type]
-        except KeyError:
-            if self._frozen:
-                raise Exception("This data set is frozen")
+    def _check_object(self, object_type: str, key: str, create: bool) -> Optional[Object]:
+        t = self._check_object_type(object_type, create)
 
-            objects = {}
-            self._objects_by_type[object_type] = objects
-            self._changed = True
+        if not t:
+            return None
 
+        ot, objects = t
         try:
             return objects[key]
         except KeyError:
-            if self._frozen:
-                raise Exception("This data set is frozen")
+            self._assert_not_frozen()
+
+            if not create:
+                raise Exception("No such type: {}:{}".format(object_type, key))
 
-            ot = self.get_object_type(object_type)
             o = Object(self, ot, key)
             objects[key] = o
-            self._changed = True
             return o
 
+    def get_object_type(self, object_type: str) -> ObjectType:
+        ot, objects = self._check_object_type(object_type, False)
+
+        if not ot:
+            raise Exception("No such object type: {}".format(object_type))
+
+        return ot
+
+    def get_object(self, object_type: str, key: str) -> Object:
+        o = self._check_object(object_type, key, False)
+
+        if not o:
+            raise Exception("No such object: {}:{}".format(object_type, key))
+
+        return o
+
+    def has_object(self, object_type: str, key: str) -> bool:
+        t = self._check_object_type(object_type, False)
+
+        if t:
+            ot, objects = t
+            return key in objects
+
+        return False
+
+    def get_or_create_object(self, object_type: str, key: str) -> Object:
+        return self._check_object(object_type, key, True)
+
+    def create_object(self, object_type: str, key: str) -> Object:
+        self._assert_not_frozen()
+
+        if self.has_object(object_type, key):
+            raise Exception("Object already exist: {}:{}".format(object_type, key))
+
+        return self._check_object(object_type, key, True)
+
     def items(self):
         from itertools import chain
         return list(chain.from_iterable([objects.values() for objects in self._objects_by_type.values()]))
@@ -133,11 +176,11 @@ class DataSet(object):
         ds = DataSet(self._name)
         for objects in self._objects_by_type.values():
             for o in objects.values():
-                ds.get_object(o.object_type.name, o.key)._set_from_object(o)
+                ds.create_object(o.object_type.name, o.key)._set_from_object(o)
 
         for objects in other._objects_by_type.values():
             for o in objects.values():
-                ds.get_object(o.object_type.name, o.key)._set_from_object(o)
+                ds.get_or_create_object(o.object_type.name, o.key)._set_from_object(o)
 
         return ds
 
@@ -149,8 +192,11 @@ class DataSetManager(object):
     def metafile_for_ds(self, ds_name) -> Path:
         return self._basedir / ds_name / "data-set.ini"
 
-    def create_rw(self, name, inputs: List[str]) -> "LazyDataSet":
-        return LazyDataSet(self, name, inputs)
+    def create_rw(self, name, inputs: List[str] = None) -> "LazyDataSet":
+        return LazyDataSet(self, False, name, inputs if inputs else [])
+
+    def create_ro(self, inputs: List[str]) -> "LazyDataSet":
+        return LazyDataSet(self, True, None, inputs)
 
     def load(self, name, freeze=False) -> DataSet:
         ds_dir = Path(name) if Path(name).is_absolute() else self._basedir / name
@@ -175,7 +221,7 @@ class DataSetManager(object):
                 key = o_path.name[:-4]
                 logger.info("    Loading key '{}'".format(key))
                 ini = self._load_ini(o_path)
-                o = ds.get_object(ot, key)
+                o = ds.create_object(ot, key)
                 for k, v in ini.items("values"):
                     o.set(k, v)
 
@@ -229,21 +275,25 @@ class DataSetManager(object):
 
 
 class LazyDataSet(object):
-    def __init__(self, dsm: DataSetManager, name, inputs):
+    def __init__(self, dsm: DataSetManager, freeze: bool, name, inputs):
         self._dsm = dsm
+        self._freeze = freeze
         self._name = name
         self._inputs = inputs
 
-    def __enter__(self):
+    def __enter__(self) -> DataSet:
         # logger.info("enter: name={}, inputs={}".format(self._name, self._inputs))
         ds = DataSet(self._name)
         for name in self._inputs:
             ds = ds.merge(self._dsm.load(name, freeze=True))
+
+        if self._freeze:
+            ds.freeze()
+
         self._ds = ds
-        return self._ds
+        return ds
 
     def __exit__(self, *args):
-        # logger.info("exit: name={}, inputs={}".format(self._name, self._inputs))
-        # logger.info("ds.size={}".format(len(self._ds.items())))
-        self._dsm.store(self._ds)
+        if not self._freeze:
+            self._dsm.store(self._ds)
         return False