[NaCl SDK] Refactor sdk_update*.

native_client_sdk/src/build_tools/sdk_tools/sdk_update_common.py

Index: native_client_sdk/src/build_tools/sdk_tools/sdk_update_common.py
diff --git a/native_client_sdk/src/build_tools/sdk_tools/sdk_update_common.py b/native_client_sdk/src/build_tools/sdk_tools/sdk_update_common.py
index ad4175ee748d5fb88ef2387780e0b5b792196e2c..e06ea1f8c09946ce4b2f58a798a44f4b1980a53a 100644
--- a/native_client_sdk/src/build_tools/sdk_tools/sdk_update_common.py
+++ b/native_client_sdk/src/build_tools/sdk_tools/sdk_update_common.py
@@ -17,6 +17,14 @@ class Error(Exception):
   pass
 
 
+def MakeDirs(directory):
+  try:
+    os.makedirs(directory)
+  except OSError as e:
+    if e.errno != errno.EEXIST:
+      raise Error('Unable to make directory "%s".\n  %s' % (directory, e))
+

[Sam Clegg, 2012/10/22 22:55:30]

I'm still not completely sold on this pattern.

I prefer an early return if os.path.exists() but that is
really a style thing I guess.

The argument I suppose is that there could be another processes racing with up. 
 However, if some other process
was to create the folder between the two calls I'd argue that its better for
this program to just crash here.  i.e. externally messing with the tree while
this program is not worth defending against.

[binji, 2012/10/23 00:14:09]

Fair enough, we use os.path.exists elsewhere -- may as well be consistent.

+
 def RemoveDir(outdir):
   """Removes the given directory
 
@@ -30,18 +38,21 @@ def RemoveDir(outdir):
     outdir: The directory to delete
 
   Raises:
-    CalledProcessError - if the delete operation fails on Windows
-    OSError - if the delete operation fails on Linux
+    Error - If this operation fails for any reason.
   """
 
   try:
-    shutil.rmtree(outdir)
-  except OSError:
-    if not os.path.exists(outdir):
-      return
-    # On Windows this could be an issue with junctions, so try again with rmdir
-    if sys.platform == 'win32':
-      subprocess.check_call(['rmdir', '/S', '/Q', outdir], shell=True)
+    try:
+      shutil.rmtree(outdir)
+    except OSError:
+      if not os.path.exists(outdir):
+        return
+      # On Windows this could be an issue with junctions, so try again with
+      # rmdir
+      if sys.platform == 'win32':
+        subprocess.check_call(['rmdir', '/S', '/Q', outdir], shell=True)
+  except Exception as e:
+    raise Error('Unable to remove directory "%s"\n  %s' % (outdir, e))
 
 
 def RenameDir(srcdir, destdir):