Mojo: Add a utility to compare old mojom_bindings_generator.py output to the current one.

mojo/tools/check_mojom_golden_files.py

Index: mojo/tools/check_mojom_golden_files.py
diff --git a/mojo/tools/check_mojom_golden_files.py b/mojo/tools/check_mojom_golden_files.py
new file mode 100755
index 0000000000000000000000000000000000000000..6c2e187c8aea48547f6b30f326b1ca2bec99371d
--- /dev/null
+++ b/mojo/tools/check_mojom_golden_files.py
@@ -0,0 +1,99 @@
+#!/usr/bin/env python
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import argparse
+import os.path
+import sys
+from filecmp import dircmp
+from shutil import rmtree
+from tempfile import mkdtemp
+
+_script_dir = os.path.dirname(os.path.abspath(__file__))
+_mojo_dir = os.path.join(_script_dir, os.pardir)
+sys.path.insert(0, os.path.join(_mojo_dir, "public", "tools", "bindings",
+                                "pylib"))
+from mojom_tests.support.find_files import FindFiles
+from mojom_tests.support.run_bindings_generator import RunBindingsGenerator
+
+
+def _ProcessDircmpResults(results, verbose=False):
+  """Prints results of directory comparison and returns true if they are
+  identical (note: the "left" directory should be the golden directory)."""
+  rv = not (bool(results.left_only) or bool(results.right_only) or \
+            bool(results.common_funny) or bool(results.funny_files) or \
+            bool(results.diff_files))
+  if verbose:
+    for f in results.left_only:
+      print "%s exists in golden directory but not in current output" % f
+    for f in results.right_only:
+      print "%s exists in current output but not in golden directory" % f
+    for f in results.common_funny + results.funny_files:
+      print "Unable to compare %s between golden directory and current output" \
+          % f
+    for f in results.diff_files:
+      print "%s differs between golden directory and current output" % f
+  for r in results.subdirs.values():
+    # If we're being verbose, check subdirectories even if we know that there
+    # are differences. Note that it's "... and rv" to avoid the short-circuit.
+    if rv or verbose:
+      rv = _ProcessDircmpResults(r, verbose=verbose) and rv
+  return rv
+
+
+def main():
+  parser = argparse.ArgumentParser()
+  parser.add_argument("--generate_golden_files", action="store_true",
+                      help=("generate golden files (does not obliterate "
+                            "directory"))
+  parser.add_argument("--keep_temp_dir", action="store_true",
+                      help="don't delete the temporary directory")
+  parser.add_argument("--verbose", action="store_true",
+                      help="spew excess verbiage")
+  parser.add_argument("golden_dir", metavar="GOLDEN_DIR",
+                      help="directory with the golden files")
+  args = parser.parse_args()
+
+  if args.generate_golden_files:
+    if os.path.exists(args.golden_dir):
+      print "WARNING: golden directory %s already exists" % args.golden_dir
+    out_dir = args.golden_dir
+  else:
+    if not os.path.exists(args.golden_dir):
+      print "ERROR: golden directory %s does not exist" % args.golden_dir
+      return 1
+    out_dir = mkdtemp()
+  if args.verbose:
+    print "Generating files to %s ..." % out_dir
+
+  mojom_files = FindFiles(_mojo_dir, "*.mojom")
+  for mojom_file in mojom_files:
+    if args.verbose:
+      print "  Processing %s ..." % os.path.relpath(mojom_file, _mojo_dir)
+    RunBindingsGenerator(out_dir, _mojo_dir, mojom_file)
+
+  if args.generate_golden_files:
+    return 0
+
+  identical = _ProcessDircmpResults(dircmp(args.golden_dir, out_dir, ignore=[]),
+                                    verbose=args.verbose)
+
+  if args.keep_temp_dir:
+    if args.verbose:
+      print "Not removing %s ..." % out_dir
+  else:
+    if args.verbose:
+      print "Removing %s ..." % out_dir
+    rmtree(out_dir)
+
+  if not identical:
+    print "FAILURE: current output differs from golden files"
+    return 1
+
+  print "SUCCESS: current output identical to golden files"
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(main())