Adding pystache to third_party

third_party/pystache/src/common.py

Index: third_party/pystache/src/common.py
diff --git a/third_party/pystache/src/common.py b/third_party/pystache/src/common.py
new file mode 100644
index 0000000000000000000000000000000000000000..fb266dd8b57026f4369a83febc831e8adad973a5
--- /dev/null
+++ b/third_party/pystache/src/common.py
@@ -0,0 +1,71 @@
+# coding: utf-8
+
+"""
+Exposes functionality needed throughout the project.
+
+"""
+
+from sys import version_info
+
+def _get_string_types():
+    # TODO: come up with a better solution for this.  One of the issues here
+    #   is that in Python 3 there is no common base class for unicode strings
+    #   and byte strings, and 2to3 seems to convert all of "str", "unicode",
+    #   and "basestring" to Python 3's "str".
+    if version_info < (3, ):
+         return basestring
+    # The latter evaluates to "bytes" in Python 3 -- even after conversion by 2to3.
+    return (unicode, type(u"a".encode('utf-8')))
+
+
+_STRING_TYPES = _get_string_types()
+
+
+def is_string(obj):
+    """
+    Return whether the given object is a byte string or unicode string.
+
+    This function is provided for compatibility with both Python 2 and 3
+    when using 2to3.
+
+    """
+    return isinstance(obj, _STRING_TYPES)
+
+
+# This function was designed to be portable across Python versions -- both
+# with older versions and with Python 3 after applying 2to3.
+def read(path):
+    """
+    Return the contents of a text file as a byte string.
+
+    """
+    # Opening in binary mode is necessary for compatibility across Python
+    # 2 and 3.  In both Python 2 and 3, open() defaults to opening files in
+    # text mode.  However, in Python 2, open() returns file objects whose
+    # read() method returns byte strings (strings of type `str` in Python 2),
+    # whereas in Python 3, the file object returns unicode strings (strings
+    # of type `str` in Python 3).
+    f = open(path, 'rb')
+    # We avoid use of the with keyword for Python 2.4 support.
+    try:
+        return f.read()
+    finally:
+        f.close()
+
+
+class MissingTags(object):
+
+    """Contains the valid values for Renderer.missing_tags."""
+
+    ignore = 'ignore'
+    strict = 'strict'
+
+
+class PystacheError(Exception):
+    """Base class for Pystache exceptions."""
+    pass
+
+
+class TemplateNotFoundError(PystacheError):
+    """An exception raised when a template is not found."""
+    pass