Improve license checker line ending validation

The license checker previously assumed that the
lines of the license will always end with \n
characters. However when checking a file
with \r\n line endings (should only happen for test files)
the checker can incorrectly report invalid license
as the line endings are incorrect.

Additional note #1: in Python when reading a file
in text mode it can happen that the line endings are
converted to the host system's line ending.
That is the `\r\n` will be converted to `\n` on Linux.
To resolve this problem the io module to disable
the line ending conversion.

Additional note #2: it is possible that there
are input test files which are not utf-8 conformant
(eg.: to test the parser). These files can't be read
as utf-8 strings and an exception would occur.
By ignoring these errors the tool can check
the file's license. In the license text there is no
invalid utf-8 character so the check will work
correctly.

JerryScript-DCO-1.0-Signed-off-by: Peter Gal [email protected]

tools/check-license.py

@@ -16,25 +16,26 @@
 
 from __future__ import print_function
 
+import io
 import os
 import re
 import sys
 import settings
 
 LICENSE = re.compile(
-    r'((#|//|\*) Copyright .*\n'
-    r')+\s?\2\n'
-    r'\s?\2 Licensed under the Apache License, Version 2.0 \(the "License"\);\n'
-    r'\s?\2 you may not use this file except in compliance with the License.\n'
-    r'\s?\2 You may obtain a copy of the License at\n'
-    r'\s?\2\n'
-    r'\s?\2     http://www.apache.org/licenses/LICENSE-2.0\n'
-    r'\s?\2\n'
-    r'\s?\2 Unless required by applicable law or agreed to in writing, software\n'
-    r'\s?\2 distributed under the License is distributed on an "AS IS" BASIS\n'
-    r'\s?\2 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n'
-    r'\s?\2 See the License for the specific language governing permissions and\n'
-    r'\s?\2 limitations under the License.\n'
+    r'((#|//|\*) Copyright .*(\r\n|\n|\r)'
+    r')+\s?\2\3'
+    r'\s?\2 Licensed under the Apache License, Version 2.0 \(the "License"\);\3'
+    r'\s?\2 you may not use this file except in compliance with the License.\3'
+    r'\s?\2 You may obtain a copy of the License at\3'
+    r'\s?\2\3'
+    r'\s?\2     http://www.apache.org/licenses/LICENSE-2.0\3'
+    r'\s?\2\3'
+    r'\s?\2 Unless required by applicable law or agreed to in writing, software\3'
+    r'\s?\2 distributed under the License is distributed on an "AS IS" BASIS\3'
+    r'\s?\2 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\3'
+    r'\s?\2 See the License for the specific language governing permissions and\3'
+    r'\s?\2 limitations under the License.\3'
 )
 
 INCLUDE_DIRS = [
@@ -78,7 +79,7 @@ def main():
             for fname in files:
                 if any(fname.endswith(ext) for ext in EXTENSIONS):
                     fpath = os.path.join(root, fname)
-                    with open(fpath) as curr_file:
+                    with io.open(fpath, 'r', errors='ignore', newline='') as curr_file:
                         if not LICENSE.search(curr_file.read()):
                             print('%s: incorrect license' % fpath)
                             is_ok = False