1 files changed, 75 insertions, 0 deletions
diff --git a/tools/run_tests/python_utils/watch_dirs.py b/tools/run_tests/python_utils/watch_dirs.py
new file mode 100755
index 0000000000..21ef23e158
--- /dev/null
+++ b/tools/run_tests/python_utils/watch_dirs.py
@@ -0,0 +1,75 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Helper to watch a (set) of directories for modifications."""
+
+import os
+import time
+
+
+class DirWatcher(object):
+  """Helper to watch a (set) of directories for modifications."""
+
+  def __init__(self, paths):
+    if isinstance(paths, basestring):
+      paths = [paths]
+    self._done = False
+    self.paths = list(paths)
+    self.lastrun = time.time()
+    self._cache = self._calculate()
+
+  def _calculate(self):
+    """Walk over all subscribed paths, check most recent mtime."""
+    most_recent_change = None
+    for path in self.paths:
+      if not os.path.exists(path):
+        continue
+      if not os.path.isdir(path):
+        continue
+      for root, _, files in os.walk(path):
+        for f in files:
+          if f and f[0] == '.': continue
+          try:
+            st = os.stat(os.path.join(root, f))
+          except OSError as e:
+            if e.errno == os.errno.ENOENT:
+              continue
+            raise
+          if most_recent_change is None:
+            most_recent_change = st.st_mtime
+          else:
+            most_recent_change = max(most_recent_change, st.st_mtime)
+    return most_recent_change
+
+  def most_recent_change(self):
+    if time.time() - self.lastrun > 1:
+      self._cache = self._calculate()
+      self.lastrun = time.time()
+    return self._cache
+