From 65bbfdb8123b4ea3e15b967b5b03b4b4335c0040 Mon Sep 17 00:00:00 2001
From: Pierre Bourdon <delroth@gmail.com>
Date: Fri, 21 Feb 2014 03:16:25 +0100
Subject: [PATCH] Add a tools that detects include cycles in the Dolphin
 codebase.

---
 Tools/find-includes-cycles.py | 80 +++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100755 Tools/find-includes-cycles.py

diff --git a/Tools/find-includes-cycles.py b/Tools/find-includes-cycles.py
new file mode 100755
index 0000000000..c4139cd7a0
--- /dev/null
+++ b/Tools/find-includes-cycles.py
@@ -0,0 +1,80 @@
+#! /usr/bin/env python
+
+'''
+Run this script from Source/Core/ to find all the #include cycles.
+'''
+
+import subprocess
+
+def get_local_includes_for(path):
+    lines = open(path).read().split('\n')
+    includes = [l.strip() for l in lines if l.strip().startswith('#include')]
+    return [i.split()[1][1:-1] for i in includes if '"' in i.split()[1]]
+
+def find_all_files():
+    '''Could probably use os.walk, but meh.'''
+    f = subprocess.check_output(['find', '.', '-name', '*.h'],
+                                universal_newlines=True).strip().split('\n')
+    return [p[2:] for p in f]
+
+def make_include_graph():
+    return { f: get_local_includes_for(f) for f in find_all_files() }
+
+def strongly_connected_components(graph):
+    """
+    Tarjan's Algorithm (named for its discoverer, Robert Tarjan) is a graph theory algorithm
+    for finding the strongly connected components of a graph.
+
+    Based on: http://en.wikipedia.org/wiki/Tarjan%27s_strongly_connected_components_algorithm
+    """
+
+    index_counter = [0]
+    stack = []
+    lowlinks = {}
+    index = {}
+    result = []
+
+    def strongconnect(node):
+        # set the depth index for this node to the smallest unused index
+        index[node] = index_counter[0]
+        lowlinks[node] = index_counter[0]
+        index_counter[0] += 1
+        stack.append(node)
+
+        # Consider successors of `node`
+        try:
+            successors = graph[node]
+        except:
+            successors = []
+        for successor in successors:
+            if successor not in lowlinks:
+                # Successor has not yet been visited; recurse on it
+                strongconnect(successor)
+                lowlinks[node] = min(lowlinks[node],lowlinks[successor])
+            elif successor in stack:
+                # the successor is in the stack and hence in the current strongly connected component (SCC)
+                lowlinks[node] = min(lowlinks[node],index[successor])
+
+        # If `node` is a root node, pop the stack and generate an SCC
+        if lowlinks[node] == index[node]:
+            connected_component = []
+
+            while True:
+                successor = stack.pop()
+                connected_component.append(successor)
+                if successor == node: break
+            component = tuple(connected_component)
+            # storing the result
+            result.append(component)
+
+    for node in graph:
+        if node not in lowlinks:
+            strongconnect(node)
+
+    return result
+
+if __name__ == '__main__':
+    comp = strongly_connected_components(make_include_graph())
+    for c in comp:
+        if len(c) != 1:
+            print(c)