From ca36dcc98c478e2cb0bef544e23a2a654dedde8a Mon Sep 17 00:00:00 2001
From: Sverre Rabbelier <sverre@rabbelier.nl>
Date: Mon, 14 Jul 2008 18:44:01 +0200
Subject: [PATCH] Add an option to ignore parent in the 'belongs to' metric

For repositories with long history it is faster to first
call 'git rev-list' for the target commit and then ignore
those commits. However, for smaller repositories the
overhead of all these rev-lists makes it more slow.
---
 src/git_stats/branch.py | 41 +++++++++++++++++++++++++++++------------
 1 file changed, 29 insertions(+), 12 deletions(-)

diff --git a/src/git_stats/branch.py b/src/git_stats/branch.py
index 4b0b6a1..e3d9459 100644
--- a/src/git_stats/branch.py
+++ b/src/git_stats/branch.py
@@ -82,7 +82,7 @@ def _bestMetric(metrics):
 
   return min, champs
 
-def _calculateDilution(target, start, parent_lists, global_memory):
+def _calculateDilution(target, start, parent_lists, global_memory, ignore=[]):
   """Calculates the dilution for the specified commit.
 
   Args:
@@ -90,6 +90,7 @@ def _calculateDilution(target, start, parent_lists, global_memory):
     start: The initial metric information.
     parent_list: A dictionary with commits and their parents.
     global_memory: A dictionary with all commits and their parents.
+    ignore: The parent commits of the target commit which should be ignored.
   """
 
   metrics = []
@@ -103,25 +104,29 @@ def _calculateDilution(target, start, parent_lists, global_memory):
   while stack:
     current = stack.pop()
 
+    # We found what we are looking for
+    if target == current.commit:
+      metrics.append(current)
+      continue
+
+    # Ignore commits that are past the target
+    if current.commit in ignore:
+      continue
+
     # If we already checked this commit, don't add it again
     if memory.has_key(current.commit):
       dilution = memory[current.commit]
       if dilution <= current.dilution:
-	continue
+        continue
 
     if global_memory.has_key(current.commit):
       dilution = global_memory[current.commit]
       if dilution < current.dilution:
-	continue
+        continue
 
     memory[current.commit] = current.dilution
     global_memory[current.commit] = current.dilution
 
-    # We found what we are looking for
-    if target == current.commit:
-      metrics.append(current)
-      continue
-
     parents = parent_lists[current.commit]
 
     # Root commit, we can't go any further
@@ -130,9 +135,9 @@ def _calculateDilution(target, start, parent_lists, global_memory):
 
     for parent in parents:
       if parent == parents[0]:
-	newdilution = current.dilution
+        newdilution = current.dilution
       else:
-	newdilution = current.dilution + 1
+        newdilution = current.dilution + 1
 
       next = Metric()
       next.commit = parent
@@ -202,13 +207,19 @@ def getParentList(commits):
 
   return parent_list
 
-def belongsTo(commit, branch_map, parent_list, pretty_names={}, debug=False):
+def belongsTo(commit,
+              branch_map,
+              parent_list,
+              pretty_names={},
+              debug=False,
+              ignore_parents=False):
   """Returns which branches the specified commit belongs to
 
   Args:
     commit: The commit to examine.
     branch_map: A dictionary of all refs and their hashes.
     parent_list: A dictionary with tuples of refs and their rev-lists.
+    pretty_names: A dictionary with commits and their names
     debug: Whether to return debug information as well.
 
   Returns: A list of branches that the commit belongs to.
@@ -223,6 +234,12 @@ def belongsTo(commit, branch_map, parent_list, pretty_names={}, debug=False):
 
   metrics = []
 
+  if ignore_parents:
+    result = git.rev_list(commit)
+    ignore = set(result.split('\n'))
+  else:
+    ignore = []
+
   debugPrint(debug, "Checking branches now:")
 
   memory = {}
@@ -236,7 +253,7 @@ def belongsTo(commit, branch_map, parent_list, pretty_names={}, debug=False):
     metric.dilution = 0
 
     # Find the dilution for this branch
-    metric = _calculateDilution(commit, metric, parent_list, memory)
+    metric = _calculateDilution(commit, metric, parent_list, memory, ignore)
     metrics = metrics + metric
 
   debugPrint(debug, "Done.\n")
-- 
2.11.4.GIT