1 files changed, 76 insertions, 0 deletions
diff --git a/gitlint/shell.py b/gitlint/shell.py
new file mode 100644
index 0000000..965f492
--- /dev/null
+++ b/gitlint/shell.py
@@ -0,0 +1,76 @@
+
+"""
+This module implements a shim for the 'sh' library, mainly for use on Windows (sh is not supported on Windows).
+We might consider removing the 'sh' dependency alltogether in the future, but 'sh' does provide a few
+capabilities wrt dealing with more edge-case environments on *nix systems that might be useful.
+"""
+
+import subprocess
+import sys
+from gitlint.utils import ustr, USE_SH_LIB
+
+if USE_SH_LIB:
+    from sh import git  # pylint: disable=unused-import,import-error
+    # import exceptions separately, this makes it a little easier to mock them out in the unit tests
+    from sh import CommandNotFound, ErrorReturnCode  # pylint: disable=import-error
+else:
+
+    class CommandNotFound(Exception):
+        """ Exception indicating a command was not found during execution """
+        pass
+
+    class ShResult(object):
+        """ Result wrapper class. We use this to more easily migrate from using https://amoffat.github.io/sh/ to using
+        the builtin subprocess. module """
+
+        def __init__(self, full_cmd, stdout, stderr='', exitcode=0):
+            self.full_cmd = full_cmd
+            self.stdout = stdout
+            self.stderr = stderr
+            self.exit_code = exitcode
+
+        def __str__(self):
+            return self.stdout
+
+    class ErrorReturnCode(ShResult, Exception):
+        """ ShResult subclass for unexpected results (acts as an exception). """
+        pass
+
+    def git(*command_parts, **kwargs):
+        """ Git shell wrapper.
+        Implemented as separate function here, so we can do a 'sh' style imports:
+        `from shell import git`
+        """
+        args = ['git'] + list(command_parts)
+        return _exec(*args, **kwargs)
+
+    def _exec(*args, **kwargs):
+        if sys.version_info[0] == 2:
+            no_command_error = OSError  # noqa pylint: disable=undefined-variable,invalid-name
+        else:
+            no_command_error = FileNotFoundError  # noqa pylint: disable=undefined-variable
+
+        pipe = subprocess.PIPE
+        popen_kwargs = {'stdout': pipe, 'stderr': pipe, 'shell': kwargs['_tty_out']}
+        if '_cwd' in kwargs:
+            popen_kwargs['cwd'] = kwargs['_cwd']
+
+        try:
+            p = subprocess.Popen(args, **popen_kwargs)
+            result = p.communicate()
+        except no_command_error:
+            raise CommandNotFound
+
+        exit_code = p.returncode
+        stdout = ustr(result[0])
+        stderr = result[1]  # 'sh' does not decode the stderr bytes to unicode
+        full_cmd = '' if args is None else ' '.join(args)
+
+        # If not _ok_code is specified, then only a 0 exit code is allowed
+        ok_exit_codes = kwargs.get('_ok_code', [0])
+
+        if exit_code in ok_exit_codes:
+            return ShResult(full_cmd, stdout, stderr, exit_code)
+
+        # Unexpected error code => raise ErrorReturnCode
+        raise ErrorReturnCode(full_cmd, stdout, stderr, p.returncode)