Check in a tool that dumps graphviz output.

tools/graphviz.py

Index: tools/graphviz.py
diff --git a/tools/graphviz.py b/tools/graphviz.py
new file mode 100755
index 0000000000000000000000000000000000000000..65daab0cc6896ef531fe668d4ab22e4e04bab2e7
--- /dev/null
+++ b/tools/graphviz.py
@@ -0,0 +1,94 @@
+#!/usr/bin/python
+
+# Copyright (c) 2011 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Using the JSON dumped by the dump-dependency-json generator,
+generate input suitable for graphviz to render a dependency graph of
+targets."""
+
+import collections
+import json
+import sys
+
+def ParseTarget(target):
+  target, _, suffix = target.partition('#')
+  filename, _, target = target.partition(':')
+  return filename, target, suffix
+
+
+def LoadEdges(filename, targets):
+  """Load the edges map from the dump file, and filter it to only
+  show targets in |targets| and their depedendents."""
+
+  file = open('dump.json')
+  edges = json.load(file)
+  file.close()
+
+  # Copy out only the edges we're interested in from the full edge list.
+  target_edges = {}
+  to_visit = targets[:]
+  while to_visit:
+    src = to_visit.pop()
+    if src in target_edges:
+      continue
+    target_edges[src] = edges[src]
+    to_visit.extend(edges[src])
+
+  return target_edges
+
+
+def WriteGraph(edges):
+  """Print a graphviz graph to stdout.
+  |edges| is a map of target to a list of other targets it depends on."""
+
+  # Bucket targets by file.
+  files = collections.defaultdict(list)
+  for src, dst in edges.items():
+    build_file, target_name, toolset = ParseTarget(src)
+    files[build_file].append(src)
+
+  print 'digraph D {'
+  print '  fontsize=8'  # Used by subgraphs.
+  print '  node [fontsize=8]'
+
+  # Output nodes by file.  We must first write out each node within
+  # its file grouping before writing out any edges that may refer
+  # to those nodes.
+  for filename, targets in files.items():
+    if len(targets) == 1:
+      # If there's only one node for this file, simplify
+      # the display by making it a box without an internal node.
+      target = targets[0]
+      build_file, target_name, toolset = ParseTarget(target)
+      print '  "%s" [shape=box, label="%s\\n%s"]' % (target, filename,
+                                                     target_name)
+    else:
+      # Group multiple nodes together in a subgraph.
+      print '  subgraph "cluster_%s" {' % filename
+      print '    label = "%s"' % filename
+      for target in targets:
+        build_file, target_name, toolset = ParseTarget(target)
+        print '    "%s" [label="%s"]' % (target, target_name)
+      print '  }'
+
+  # Now that we've placed all the nodes within subgraphs, output all
+  # the edges between nodes.
+  for src, dsts in edges.items():
+    for dst in dsts:
+      print '  "%s" -> "%s"' % (src, dst)
+
+  print '}'
+
+
+if __name__ == '__main__':
+  if len(sys.argv) < 2:
+    print __doc__

[Mark Mentovai, 2011/05/26 00:38:13]

I’d send this stuff to sys.stderr.

+    print
+    print 'usage: %s target1 target2...' % (sys.argv[0])
+    sys.exit(1)
+
+  edges = LoadEdges('dump.json', sys.argv[1:])
+
+  WriteGraph(edges)