Add NodeHistoryAccumulator utility class

Merge branch 'hurthwell-refactor-2' into 'master'

See merge request persper/code-analytics!70

persper/analytics2/abstractions/callcommitgraph.py

@@ -242,6 +242,7 @@ def update_node_history(self, node_id: NodeId, commit_hexsha: str, added_lines:
             If commit_hexsha doesn't exist in history, add the entry to history.
             If commit_hexsha exists in history, the entry will be *replaced*.
                 Note the entire node history entry of this hexsha will be replaced rather than merged.
+            To accumulate multiple modifications to a node in the same commit, use `NodeHistoryAccumulator` helper class.
         """
         pass
 

persper/analytics2/utilities.py

@@ -0,0 +1,62 @@
+from persper.analytics2.abstractions.callcommitgraph import IWriteOnlyCallCommitGraph, NodeId
+
+
+class NodeHistoryAccumulator():
+    """
+    Provides convenient methods for accumulating node history.
+    (i.e. the added/removed lines to the same node in a single commit)
+    """
+
+    def __init__(self):
+        # [NodeId]: [added_lines, removed_lines]
+        self._nodes = {}
+
+    def clear(self):
+        """
+        Clears all the accumulated histroy information contained in this instance.
+        """
+        self._nodes.clear()
+
+    def add(self, node_id: NodeId, added_lines: int = 0, removed_lines: int = 0):
+        """
+        Accumulates the added/removed lines of code to the specific node_id.
+        """
+        info = self._nodes.get(node_id, None)
+        if info == None:
+            if not isinstance(node_id, NodeId):
+                raise ValueError("node_id should be NodeId.")
+            if not isinstance(added_lines, int):
+                raise ValueError("added_lines should be int.")
+            if not isinstance(removed_lines, int):
+                raise ValueError("removed_lines should be int.")
+            if added_lines != 0 or removed_lines != 0:
+                info = [added_lines, removed_lines]
+                self._nodes[node_id] = info
+        else:
+            info[0] += added_lines
+            info[1] += removed_lines
+
+    def get(self, node_id: NodeId):
+        """
+        Gets the accumulated added/removed lines of code for the specified node ID.
+        returns
+            (added_lines: int, removed_lines: int)
+        """
+        info = self._nodes.get(node_id, None)
+        if info == None:
+            if not isinstance(node_id, NodeId):
+                raise ValueError("node_id should be NodeId.")
+            return 0, 0
+        return info[0], info[1]
+
+    def apply(self, graph: IWriteOnlyCallCommitGraph, commit_hexsha: str):
+        """
+        Applies the node history contained in this instance to the specified call commit graph.
+        params
+            graph: the call commit graph to be updated.
+            commit_hexsha: When updating the call commit graph, specify the current commit hexsha.
+        remarks
+            You may want to call `clear` to reset the change history after calling this method. 
+        """
+        for id, (added, removed) in self._nodes:
+            graph.update_node_history(id, commit_hexsha, added, removed)

test/analytics2/utilities.py

@@ -0,0 +1,20 @@
+from persper.analytics2.utilities import NodeHistoryAccumulator
+from persper.analytics2.abstractions.callcommitgraph import NodeId
+
+
+def test_node_history_accumulator():
+    nodeHistory = NodeHistoryAccumulator()
+    testId0 = NodeId("CTest0", "cpp")
+    testId1 = NodeId("CTest1", "cpp")
+    testId2 = NodeId("CTest2", "cpp")
+    nodeHistory.add(testId1, 10, 20)
+    nodeHistory.add(testId2, -10, 20)
+    nodeHistory.add(testId1, 5, -5)
+    assert nodeHistory.get(testId0) == (0, 0)
+    assert nodeHistory.get(testId1) == (15, 15)
+    assert nodeHistory.get(testId2) == (-10, 20)
+    # TODO test `apply` with MemoryCCG
+    nodeHistory.clear()
+    assert nodeHistory.get(testId0) == (0, 0)
+    assert nodeHistory.get(testId1) == (0, 0)
+    assert nodeHistory.get(testId2) == (0, 0)