Add infrastructure to download golang and build AppRTC collider.

utils.py

+#!/usr/bin/python
+# Copyright 201t The Chromium Authors. All rights reserved.

[kjellander_chromium, 2014/12/08 13:58:08]

201t -> 2014.

[phoglund_chromium, 2014/12/08 14:26:16]

Done.

+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Utilities for all our deps-management stuff."""
+
+import hashlib
+import os
+import shutil
+import sys
+import tarfile
+import zipfile
+
+
+def ComputeSHA1(path):
+  if not os.path.exists(path):

[kjellander_chromium, 2014/12/08 13:58:08]

Returning 0 for non-existing files would be unexpected behavior to me.
I suggest checking for file existence in the calling code and let this code fail
hard on opening the file if it's missing.

[phoglund_chromium, 2014/12/08 14:26:16]

That would introduce a lot of cruft in the calling code though. I would have to
do old_sha1 = utils.ComputeSHA1(file_path) if os.path.exists(file_path) else 0,
or worse

if not os.path.exists(file_path) or old_sha1 != utils.ComputeSHA1(file_path):
  download, unpack etc

I think this is more readable. I guess there is a chance a file will checksum to
0, but the chance is approximately zero.

[kjellander_chromium, 2014/12/08 14:52:25]

Fair enough.

+    return 0
+
+  sha1 = hashlib.sha1()
+  file_to_hash = open(path, 'rb')
+  try:
+    sha1.update(file_to_hash.read())
+  finally:
+    file_to_hash.close()
+
+  return sha1.hexdigest()
+
+
+# This is necessary since Windows won't allow us to unzip onto an existing dir.

[kjellander_chromium, 2014/12/08 13:58:08]

"This is" is referencing what? I think this should be update now that it moved
into utils.py.

[phoglund_chromium, 2014/12/08 14:26:16]

Deleted the comment.

[phoglund_chromium, 2014/12/08 14:26:16]

Done.

+def DeleteDirNextToGclient(directory):
+  # Sanity check to avoid nuking the wrong dirs.
+  if not os.path.exists('.gclient'):
+    raise Exception('Invoked from wrong dir; invoke from dir with .gclient')
+  print 'Deleting %s in %s...' % (directory, os.getcwd())
+  shutil.rmtree(directory, ignore_errors=True)
+
+
+def UnpackToWorkingDir(archive_path):
+  extension = os.path.splitext(archive_path)[1]
+  if extension == '.zip':
+    _Unzip(archive_path)
+  else:
+    _Untar(archive_path)
+
+
+def _Unzip(path):
+  print 'Unzipping %s in %s...' % (path, os.getcwd())
+  zip_file = zipfile.ZipFile(path)
+  try:
+    zip_file.extractall()
+  finally:
+    zip_file.close()
+
+
+def _Untar(path):
+  print 'Untarring %s in %s...' % (path, os.getcwd())
+  tar_file = tarfile.open(path, 'r:gz')
+  try:
+    tar_file.extractall()
+  finally:
+    tar_file.close()
+
+
+def GetPlatform():
+  if sys.platform.startswith('win'):
+    return 'win'
+  if sys.platform.startswith('linux'):
+    return 'linux'
+  if sys.platform.startswith('darwin'):
+    return 'mac'
+  raise Exception("Can't run on platform %s." % sys.platform)

[kjellander_chromium, 2014/12/08 13:58:08]

Single-quote string and escape it like Can\'t instead?

[phoglund_chromium, 2014/12/08 14:26:16]

I watched a python readability review and this was actually preferred over
escaping '.

[kjellander_chromium, 2014/12/08 14:52:25]

Acknowledged.

+