1 files changed, 81 insertions, 0 deletions
diff --git a/gitlint-core/gitlint/utils.py b/gitlint-core/gitlint/utils.py
new file mode 100644
index 0000000..c91184b
--- /dev/null
+++ b/gitlint-core/gitlint/utils.py
@@ -0,0 +1,81 @@
+# pylint: disable=bad-option-value,unidiomatic-typecheck,undefined-variable,no-else-return
+import codecs
+import platform
+import os
+
+import locale
+
+# Note: While we can easily inline the logic related to the constants set in this module, we deliberately create
+# small functions that encapsulate that logic as this enables easy unit testing. In particular, by creating functions
+# we can easily mock the dependencies during testing, which is not possible if the code is not enclosed in a function
+# and just executed at import-time.
+
+########################################################################################################################
+LOG_FORMAT = '%(levelname)s: %(name)s %(message)s'
+
+########################################################################################################################
+# PLATFORM_IS_WINDOWS
+
+
+def platform_is_windows():
+    return "windows" in platform.system().lower()
+
+
+PLATFORM_IS_WINDOWS = platform_is_windows()
+
+########################################################################################################################
+# USE_SH_LIB
+# Determine whether to use the `sh` library
+# On windows we won't want to use the sh library since it's not supported - instead we'll use our own shell module.
+# However, we want to be able to overwrite this behavior for testing using the GITLINT_USE_SH_LIB env var.
+
+
+def use_sh_library():
+    gitlint_use_sh_lib_env = os.environ.get('GITLINT_USE_SH_LIB', None)
+    if gitlint_use_sh_lib_env:
+        return gitlint_use_sh_lib_env == "1"
+    return not PLATFORM_IS_WINDOWS
+
+
+USE_SH_LIB = use_sh_library()
+
+########################################################################################################################
+# DEFAULT_ENCODING
+
+
+def getpreferredencoding():
+    """ Modified version of local.getpreferredencoding() that takes into account LC_ALL, LC_CTYPE, LANG env vars
+        on windows and falls back to UTF-8. """
+    fallback_encoding = "UTF-8"
+    default_encoding = locale.getpreferredencoding() or fallback_encoding
+
+    # On Windows, we mimic git/linux by trying to read the LC_ALL, LC_CTYPE, LANG env vars manually
+    # (on Linux/MacOS the `getpreferredencoding()` call will take care of this).
+    # We fallback to UTF-8
+    if PLATFORM_IS_WINDOWS:
+        default_encoding = fallback_encoding
+        for env_var in ["LC_ALL", "LC_CTYPE", "LANG"]:
+            encoding = os.environ.get(env_var, False)
+            if encoding:
+                # Support dotted (C.UTF-8) and non-dotted (C or UTF-8) charsets:
+                # If encoding contains a dot: split and use second part, otherwise use everything
+                dot_index = encoding.find(".")
+                if dot_index != -1:
+                    default_encoding = encoding[dot_index + 1:]
+                else:
+                    default_encoding = encoding
+                break
+
+        # We've determined what encoding the user *wants*, let's now check if it's actually a valid encoding on the
+        # system. If not, fallback to UTF-8.
+        # This scenario is fairly common on Windows where git sets LC_CTYPE=C when invoking the commit-msg hook, which
+        # is not a valid encoding in Python on Windows.
+        try:
+            codecs.lookup(default_encoding)  # pylint: disable=no-member
+        except LookupError:
+            default_encoding = fallback_encoding
+
+    return default_encoding
+
+
+DEFAULT_ENCODING = getpreferredencoding()