add url_utils to common repo from skia repo

Once gs_utils.py is moved into common, these would be the only files left in https://skia.googlesource.com/skia/+/master/tools/pyutils/ .  So let's just move them all...

BUG=skia:2682
R=borenet@google.com

Review URL: https://codereview.chromium.org/382933002

py/utils/url_utils.py

diff --git a/py/utils/url_utils.py b/py/utils/url_utils.py
new file mode 100755
index 0000000..235ab5b
--- /dev/null
+++ b/py/utils/url_utils.py
@@ -0,0 +1,61 @@
+#!/usr/bin/python
+
+"""
+Copyright 2014 Google Inc.
+
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file.
+
+Utilities for working with URLs.
+"""
+
+# System-level imports
+import contextlib
+import os
+import shutil
+import urllib
+import urlparse
+
+
+def create_filepath_url(filepath):
+  """ Returns a file:/// URL pointing at the given filepath on local disk.
+
+  Args:
+    filepath: string; path to a file on local disk (may be absolute or relative,
+        and the file does not need to exist)
+
+  Returns:
+    A file:/// URL pointing at the file.  Regardless of whether filepath was
+        specified as a relative or absolute path, the URL will contain an
+        absolute path to the file.
+
+  Raises:
+    An Exception, if filepath is already a URL.
+  """
+  if urlparse.urlparse(filepath).scheme:
+    raise Exception('"%s" is already a URL' % filepath)
+  return urlparse.urljoin(
+      'file:', urllib.pathname2url(os.path.abspath(filepath)))
+
+
+def copy_contents(source_url, dest_path, create_subdirs_if_needed=False):
+  """ Copies the full contents of the URL 'source_url' into
+  filepath 'dest_path'.
+
+  Args:
+    source_url: string; complete URL to read from
+    dest_path: string; complete filepath to write to (may be absolute or
+        relative)
+    create_subdirs_if_needed: boolean; whether to create subdirectories as
+        needed to create dest_path
+
+  Raises:
+    Some subclass of Exception if unable to read source_url or write dest_path.
+  """
+  if create_subdirs_if_needed:
+    dest_dir = os.path.dirname(dest_path)
+    if not os.path.exists(dest_dir):
+      os.makedirs(dest_dir)
+  with contextlib.closing(urllib.urlopen(source_url)) as source_handle:
+    with open(dest_path, 'wb') as dest_handle:
+      shutil.copyfileobj(fsrc=source_handle, fdst=dest_handle)

py/utils/url_utils_test.py

diff --git a/py/utils/url_utils_test.py b/py/utils/url_utils_test.py
new file mode 100755
index 0000000..ef3d8c8
--- /dev/null
+++ b/py/utils/url_utils_test.py
@@ -0,0 +1,61 @@
+#!/usr/bin/python
+
+"""
+Copyright 2014 Google Inc.
+
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file.
+
+Test url_utils.py
+"""
+
+# System-level imports
+import os
+import shutil
+import tempfile
+import unittest
+import urllib
+
+# Imports from within Skia
+import url_utils
+
+
+class UrlUtilsTest(unittest.TestCase):
+
+  def test_create_filepath_url(self):
+    """Tests create_filepath_url(). """
+    with self.assertRaises(Exception):
+      url_utils.create_filepath_url('http://1.2.3.4/path')
+    # Pass absolute filepath.
+    self.assertEquals(
+        url_utils.create_filepath_url(
+            '%sdir%sfile' % (os.path.sep, os.path.sep)),
+        'file:///dir/file')
+    # Pass relative filepath.
+    self.assertEquals(
+        url_utils.create_filepath_url(os.path.join('dir', 'file')),
+        'file://%s/dir/file' % urllib.pathname2url(os.getcwd()))
+
+  def test_copy_contents(self):
+    """Tests copy_contents(). """
+    contents = 'these are the contents'
+    tempdir_path = tempfile.mkdtemp()
+    try:
+      source_path = os.path.join(tempdir_path, 'source')
+      source_url = url_utils.create_filepath_url(source_path)
+      with open(source_path, 'w') as source_handle:
+        source_handle.write(contents)
+      dest_path = os.path.join(tempdir_path, 'new_subdir', 'dest')
+      # Destination subdir does not exist, so copy_contents() should fail
+      # if create_subdirs_if_needed is False.
+      with self.assertRaises(Exception):
+        url_utils.copy_contents(source_url=source_url,
+                                dest_path=dest_path,
+                                create_subdirs_if_needed=False)
+      # If create_subdirs_if_needed is True, it should work.
+      url_utils.copy_contents(source_url=source_url,
+                              dest_path=dest_path,
+                              create_subdirs_if_needed=True)
+      self.assertEquals(open(dest_path).read(), contents)
+    finally:
+      shutil.rmtree(tempdir_path)