1 files changed, 91 insertions, 0 deletions
diff --git a/utils/file_utils.py b/utils/file_utils.py
new file mode 100644
index 00000000..987e88ad
--- /dev/null
+++ b/utils/file_utils.py
@@ -0,0 +1,91 @@
+#!/usr/bin/python
+
+# Copyright 2011 Google Inc. All Rights Reserved.
+
+import errno
+import hashlib
+import os
+import shutil
+
+
+class FileUtils(object):
+  """Utilities for operations on files."""
+  _instance = None
+  DRY_RUN = False
+
+  @classmethod
+  def Configure(cls, dry_run):
+    cls.DRY_RUN = dry_run
+
+  def __new__(cls, *args, **kwargs):
+    if not cls._instance:
+      if cls.DRY_RUN:
+        cls._instance = super(FileUtils, cls).__new__(MockFileUtils, *args,
+                                                      **kwargs)
+      else:
+        cls._instance = super(FileUtils, cls).__new__(cls, *args,
+                                                      **kwargs)
+    return cls._instance
+
+  def Md5File(self, filename, block_size=2 ** 10):
+    md5 = hashlib.md5()
+
+    with open(filename) as f:
+      while True:
+        data = f.read(block_size)
+        if not data:
+          break
+        md5.update(data)
+
+    return md5.hexdigest()
+
+  def CanonicalizeChromeOSRoot(self, chromeos_root):
+    chromeos_root = os.path.expanduser(chromeos_root)
+    if os.path.isfile(os.path.join(chromeos_root,
+                                   "src/scripts/enter_chroot.sh")):
+      return chromeos_root
+    else:
+      return None
+
+  def ChromeOSRootFromImage(self, chromeos_image):
+    chromeos_root = os.path.join(os.path.dirname(chromeos_image),
+                                 "../../../../..")
+    return self.CanonicalizeChromeOSRoot(chromeos_root)
+
+  def MkDirP(self, path):
+    try:
+      os.makedirs(path)
+    except OSError as exc:
+      if exc.errno == errno.EEXIST:
+        pass
+      else:
+        raise
+
+  def RmDir(self, path):
+    shutil.rmtree(path, ignore_errors=True)
+
+  def WriteFile(self, path, contents):
+    with open(path, "wb") as f:
+      f.write(contents)
+
+
+class MockFileUtils(FileUtils):
+  """Mock class for file utilities."""
+
+  def Md5File(self, filename, block_size=2 ** 10):
+    return "d41d8cd98f00b204e9800998ecf8427e"
+
+  def CanonicalizeChromeOSRoot(self, chromeos_root):
+    return "/tmp/chromeos_root"
+
+  def ChromeOSRootFromImage(self, chromeos_image):
+    return "/tmp/chromeos_root"
+
+  def RmDir(self, path):
+    pass
+
+  def MkDirP(self, path):
+    pass
+
+  def WriteFile(self, path, contents):
+    pass