Move b, u helpers to util module for now

Later on we can likely nuke many uses of these

19 files changed, 46 insertions, 23 deletions

diff --git a/paramiko/_winapi.py b/paramiko/_winapi.py
index df02b114..1f55db91 100644
--- a/paramiko/_winapi.py
+++ b/paramiko/_winapi.py
@@ -9,7 +9,8 @@ in jaraco.windows and asking the author to port the fixes back here.
 import sys
 import ctypes.wintypes
 
-from paramiko.py3compat import u, builtins
+from paramiko.py3compat import builtins
+from paramiko.util import u
 
 
 ######################
diff --git a/paramiko/auth_handler.py b/paramiko/auth_handler.py
index db89670a..f18a3ed6 100644
--- a/paramiko/auth_handler.py
+++ b/paramiko/auth_handler.py
@@ -62,7 +62,7 @@ from paramiko.common import (
     cMSG_USERAUTH_BANNER,
 )
 from paramiko.message import Message
-from paramiko.py3compat import b, u
+from paramiko.util import b, u
 from paramiko.ssh_exception import (
     SSHException,
     AuthenticationException,
diff --git a/paramiko/ber.py b/paramiko/ber.py
index a59a0f93..4e93e66f 100644
--- a/paramiko/ber.py
+++ b/paramiko/ber.py
@@ -16,9 +16,9 @@
 # along with Paramiko; if not, write to the Free Software Foundation, Inc.,
 # 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA.
 from paramiko.common import max_byte, zero_byte, byte_ord, byte_chr
-from paramiko.py3compat import b
 
 import paramiko.util as util
+from paramiko.util import b
 
 
 class BERException(Exception):
diff --git a/paramiko/buffered_pipe.py b/paramiko/buffered_pipe.py
index d825efdf..79854ada 100644
--- a/paramiko/buffered_pipe.py
+++ b/paramiko/buffered_pipe.py
@@ -25,7 +25,7 @@ read operations are blocking and can have a timeout set.
 import array
 import threading
 import time
-from paramiko.py3compat import b
+from paramiko.util import b
 
 
 class PipeTimeout(IOError):
diff --git a/paramiko/ed25519key.py b/paramiko/ed25519key.py
index c9e37e0a..c8c4da6c 100644
--- a/paramiko/ed25519key.py
+++ b/paramiko/ed25519key.py
@@ -23,7 +23,7 @@ import nacl.signing
 
 from paramiko.message import Message
 from paramiko.pkey import PKey, OPENSSH_AUTH_MAGIC, _unpad_openssh
-from paramiko.py3compat import b
+from paramiko.util import b
 from paramiko.ssh_exception import SSHException, PasswordRequiredException
 
 
diff --git a/paramiko/file.py b/paramiko/file.py
index eeb2b8c6..51a6d409 100644
--- a/paramiko/file.py
+++ b/paramiko/file.py
@@ -24,9 +24,9 @@ from paramiko.common import (
     linefeed_byte,
     cr_byte_value,
 )
-from paramiko.py3compat import u, bytes_types, text_type
+from paramiko.py3compat import bytes_types, text_type
 
-from paramiko.util import ClosingContextManager
+from paramiko.util import ClosingContextManager, u
 
 
 class BufferedFile(ClosingContextManager):
diff --git a/paramiko/hostkeys.py b/paramiko/hostkeys.py
index f1b4a936..91877c25 100644
--- a/paramiko/hostkeys.py
+++ b/paramiko/hostkeys.py
@@ -28,11 +28,11 @@ else:
 from hashlib import sha1
 from hmac import HMAC
 
-from paramiko.py3compat import b, u, encodebytes, decodebytes
+from paramiko.py3compat import encodebytes, decodebytes
 
 from paramiko.dsskey import DSSKey
 from paramiko.rsakey import RSAKey
-from paramiko.util import get_logger, constant_time_bytes_eq
+from paramiko.util import get_logger, constant_time_bytes_eq, b, u
 from paramiko.ecdsakey import ECDSAKey
 from paramiko.ed25519key import Ed25519Key
 from paramiko.ssh_exception import SSHException
diff --git a/paramiko/message.py b/paramiko/message.py
index 2b5cfb0e..b555e2cd 100644
--- a/paramiko/message.py
+++ b/paramiko/message.py
@@ -25,7 +25,7 @@ from io import BytesIO
 
 from paramiko import util
 from paramiko.common import zero_byte, max_byte, one_byte
-from paramiko.py3compat import u
+from paramiko.util import u
 
 
 class Message(object):
diff --git a/paramiko/packet.py b/paramiko/packet.py
index 914e8971..a8db2582 100644
--- a/paramiko/packet.py
+++ b/paramiko/packet.py
@@ -38,8 +38,7 @@ from paramiko.common import (
     zero_byte,
     byte_ord,
 )
-from paramiko.py3compat import u
-from paramiko.util import asbytes
+from paramiko.util import asbytes, u
 from paramiko.ssh_exception import SSHException, ProxyCommandFailure
 from paramiko.message import Message
 
diff --git a/paramiko/pkey.py b/paramiko/pkey.py
index 0566efc0..254f8086 100644
--- a/paramiko/pkey.py
+++ b/paramiko/pkey.py
@@ -35,8 +35,9 @@ from cryptography.hazmat.primitives import serialization
 from cryptography.hazmat.primitives.ciphers import algorithms, modes, Cipher
 
 from paramiko import util
+from paramiko.util import u, b
 from paramiko.common import o600
-from paramiko.py3compat import u, b, encodebytes, decodebytes, string_types
+from paramiko.py3compat import encodebytes, decodebytes, string_types
 from paramiko.ssh_exception import SSHException, PasswordRequiredException
 from paramiko.message import Message
 
diff --git a/paramiko/sftp_client.py b/paramiko/sftp_client.py
index 5bb86e54..d4396399 100644
--- a/paramiko/sftp_client.py
+++ b/paramiko/sftp_client.py
@@ -28,7 +28,6 @@ from paramiko import util
 from paramiko.channel import Channel
 from paramiko.message import Message
 from paramiko.common import INFO, DEBUG, o777
-from paramiko.py3compat import b, u
 from paramiko.sftp import (
     BaseSFTP,
     CMD_OPENDIR,
@@ -66,7 +65,7 @@ from paramiko.sftp import (
 from paramiko.sftp_attr import SFTPAttributes
 from paramiko.ssh_exception import SSHException
 from paramiko.sftp_file import SFTPFile
-from paramiko.util import ClosingContextManager
+from paramiko.util import ClosingContextManager, b, u
 
 
 def _to_unicode(s):
diff --git a/paramiko/sftp_file.py b/paramiko/sftp_file.py
index 74255708..0975cba3 100644
--- a/paramiko/sftp_file.py
+++ b/paramiko/sftp_file.py
@@ -30,7 +30,7 @@ import time
 from paramiko.common import DEBUG
 
 from paramiko.file import BufferedFile
-from paramiko.py3compat import u
+from paramiko.util import u
 from paramiko.sftp import (
     CMD_CLOSE,
     CMD_READ,
diff --git a/paramiko/sftp_server.py b/paramiko/sftp_server.py
index 34cb85cf..b93c8168 100644
--- a/paramiko/sftp_server.py
+++ b/paramiko/sftp_server.py
@@ -36,8 +36,9 @@ from paramiko.sftp import (
 from paramiko.sftp_si import SFTPServerInterface
 from paramiko.sftp_attr import SFTPAttributes
 from paramiko.common import DEBUG
-from paramiko.py3compat import string_types, bytes_types, b
+from paramiko.py3compat import string_types, bytes_types
 from paramiko.server import SubsystemHandler
+from paramiko.util import b
 
 
 # known hash algorithms for the "check-file" extension
diff --git a/paramiko/transport.py b/paramiko/transport.py
index fae1babb..6abfe5d8 100644
--- a/paramiko/transport.py
+++ b/paramiko/transport.py
@@ -101,7 +101,7 @@ from paramiko.kex_gss import KexGSSGex, KexGSSGroup1, KexGSSGroup14
 from paramiko.message import Message
 from paramiko.packet import Packetizer, NeedRekeyException
 from paramiko.primes import ModulusPack
-from paramiko.py3compat import string_types, b, input
+from paramiko.py3compat import string_types, input
 from paramiko.rsakey import RSAKey
 from paramiko.ecdsakey import ECDSAKey
 from paramiko.server import ServerInterface
@@ -113,7 +113,7 @@ from paramiko.ssh_exception import (
     IncompatiblePeer,
     ProxyCommandFailure,
 )
-from paramiko.util import retry_on_signal, ClosingContextManager, clamp_value
+from paramiko.util import retry_on_signal, ClosingContextManager, clamp_value, b
 
 
 # for thread cleanup
diff --git a/paramiko/util.py b/paramiko/util.py
index a9865ec3..5e2f6392 100644
--- a/paramiko/util.py
+++ b/paramiko/util.py
@@ -318,3 +318,24 @@ def asbytes(s):
             # byte-y or buffer-y that everything will work out (or that callers
             # are capable of handling whatever it is.)
             return s
+
+
+# TODO: clean this up / force callers to assume bytes OR unicode
+def b(s, encoding="utf8"):
+    """cast unicode or bytes to bytes"""
+    if isinstance(s, bytes):
+        return s
+    elif isinstance(s, str):
+        return s.encode(encoding)
+    else:
+        raise TypeError("Expected unicode or bytes, got {!r}".format(s))
+
+# TODO: clean this up / force callers to assume bytes OR unicode
+def u(s, encoding="utf8"):
+    """cast bytes or unicode to unicode"""
+    if isinstance(s, bytes):
+        return s.decode(encoding)
+    elif isinstance(s, str):
+        return s
+    else:
+        raise TypeError("Expected unicode or bytes, got {!r}".format(s))
diff --git a/paramiko/win_pageant.py b/paramiko/win_pageant.py
index b733d813..93f74621 100644
--- a/paramiko/win_pageant.py
+++ b/paramiko/win_pageant.py
@@ -26,7 +26,7 @@ import ctypes.wintypes
 import platform
 import struct
 from paramiko.common import zero_byte
-from paramiko.py3compat import b
+from paramiko.util import b
 
 try:
     import _thread as thread  # Python 3.x
diff --git a/tests/test_agent.py b/tests/test_agent.py
index c3973bbb..01602d0e 100644
--- a/tests/test_agent.py
+++ b/tests/test_agent.py
@@ -8,7 +8,7 @@ from paramiko.agent import (
     SSH_AGENT_RSA_SHA2_512,
     AgentKey,
 )
-from paramiko.py3compat import b
+from paramiko.util import b
 
 
 class ChaosAgent:
diff --git a/tests/test_auth.py b/tests/test_auth.py
index 0f0a6169..4a960deb 100644
--- a/tests/test_auth.py
+++ b/tests/test_auth.py
@@ -35,7 +35,7 @@ from paramiko import (
     AuthenticationException,
 )
 from paramiko import AUTH_FAILED, AUTH_PARTIALLY_SUCCESSFUL, AUTH_SUCCESSFUL
-from paramiko.py3compat import u
+from paramiko.util import u
 
 from .loop import LoopSocket
 from .util import _support, slow
diff --git a/tests/test_pkey.py b/tests/test_pkey.py
index 1ed021f9..604bbfa6 100644
--- a/tests/test_pkey.py
+++ b/tests/test_pkey.py
@@ -37,7 +37,8 @@ from paramiko import (
     util,
     SSHException,
 )
-from paramiko.py3compat import b, bytes
+from paramiko.py3compat import bytes
+from paramiko.util import b
 from paramiko.common import o600, byte_chr
 
 from cryptography.exceptions import UnsupportedAlgorithm