Migrate some byte related helpers around

I feel like we should be able to just nuke byte_chr and friends at this
point, but it's not entirely obvious, so let's rock that boat later.

14 files changed, 71 insertions, 56 deletions

diff --git a/paramiko/agent.py b/paramiko/agent.py
index 17eb4568..31a16e2e 100644
--- a/paramiko/agent.py
+++ b/paramiko/agent.py
@@ -29,13 +29,12 @@ import time
 import tempfile
 import stat
 from select import select
-from paramiko.common import asbytes, io_sleep
-from paramiko.py3compat import byte_chr
+from paramiko.common import io_sleep, byte_chr
 
 from paramiko.ssh_exception import SSHException, AuthenticationException
 from paramiko.message import Message
 from paramiko.pkey import PKey
-from paramiko.util import retry_on_signal
+from paramiko.util import retry_on_signal, asbytes
 
 cSSH2_AGENTC_REQUEST_IDENTITIES = byte_chr(11)
 SSH2_AGENT_IDENTITIES_ANSWER = 12
diff --git a/paramiko/ber.py b/paramiko/ber.py
index a064e6b1..28737c55 100644
--- a/paramiko/ber.py
+++ b/paramiko/ber.py
@@ -15,8 +15,8 @@
 # You should have received a copy of the GNU Lesser General Public License
 # 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
-from paramiko.py3compat import b, byte_ord, byte_chr, long
+from paramiko.common import max_byte, zero_byte, byte_ord, byte_chr
+from paramiko.py3compat import b, long
 
 import paramiko.util as util
 
diff --git a/paramiko/common.py b/paramiko/common.py
index cf6972d5..3721efe4 100644
--- a/paramiko/common.py
+++ b/paramiko/common.py
@@ -20,7 +20,25 @@
 Common constants and global variables.
 """
 import logging
-from paramiko.py3compat import byte_chr, PY2, long, b
+import struct
+
+#
+# Formerly of py3compat.py. May be fully delete'able with a deeper look?
+#
+
+def byte_chr(c):
+    assert isinstance(c, int)
+    return struct.pack("B", c)
+
+def byte_mask(c, mask):
+    assert isinstance(c, int)
+    return struct.pack("B", c & mask)
+
+def byte_ord(c):
+    # In case we're handed a string instead of an int.
+    if not isinstance(c, int):
+        c = ord(c)
+    return c
 
 (
     MSG_DISCONNECT,
@@ -184,38 +202,12 @@ max_byte = byte_chr(0xff)
 cr_byte = byte_chr(13)
 linefeed_byte = byte_chr(10)
 crlf = cr_byte + linefeed_byte
+cr_byte_value = 13
+linefeed_byte_value = 10
+
 
-if PY2:
-    cr_byte_value = cr_byte
-    linefeed_byte_value = linefeed_byte
-else:
-    cr_byte_value = 13
-    linefeed_byte_value = 10
-
-
-def asbytes(s):
-    """
-    Coerce to bytes if possible or return unchanged.
-    """
-    try:
-        # Attempt to run through our version of b(), which does the Right Thing
-        # for string/unicode/buffer (Py2) or bytes/str (Py3), and raises
-        # TypeError if it's not one of those types.
-        return b(s)
-    except TypeError:
-        try:
-            # If it wasn't a string/byte/buffer type object, try calling an
-            # asbytes() method, which many of our internal classes implement.
-            return s.asbytes()
-        except AttributeError:
-            # Finally, just do nothing & assume this object is sufficiently
-            # byte-y or buffer-y that everything will work out (or that callers
-            # are capable of handling whatever it is.)
-            return s
-
-
-xffffffff = long(0xffffffff)
-x80000000 = long(0x80000000)
+xffffffff = 0xffffffff
+x80000000 = 0x80000000
 o666 = 438
 o660 = 432
 o644 = 420
diff --git a/paramiko/kex_curve25519.py b/paramiko/kex_curve25519.py
index 3420fb4f..8f66609a 100644
--- a/paramiko/kex_curve25519.py
+++ b/paramiko/kex_curve25519.py
@@ -9,7 +9,8 @@ from cryptography.hazmat.primitives.asymmetric.x25519 import (
 )
 
 from paramiko.message import Message
-from paramiko.py3compat import byte_chr, long
+from paramiko.common import byte_chr
+from paramiko.py3compat import long
 from paramiko.ssh_exception import SSHException
 
 
diff --git a/paramiko/kex_ecdh_nist.py b/paramiko/kex_ecdh_nist.py
index 19de2431..eb9eff74 100644
--- a/paramiko/kex_ecdh_nist.py
+++ b/paramiko/kex_ecdh_nist.py
@@ -4,8 +4,9 @@ RFC 5656, Section 4
 """
 
 from hashlib import sha256, sha384, sha512
+from paramiko.common import byte_chr
 from paramiko.message import Message
-from paramiko.py3compat import byte_chr, long
+from paramiko.py3compat import long
 from paramiko.ssh_exception import SSHException
 from cryptography.hazmat.backends import default_backend
 from cryptography.hazmat.primitives.asymmetric import ec
diff --git a/paramiko/kex_gex.py b/paramiko/kex_gex.py
index e6ed2392..7bf24ddd 100644
--- a/paramiko/kex_gex.py
+++ b/paramiko/kex_gex.py
@@ -26,9 +26,8 @@ import os
 from hashlib import sha1, sha256
 
 from paramiko import util
-from paramiko.common import DEBUG
+from paramiko.common import DEBUG, byte_chr, byte_ord, byte_mask
 from paramiko.message import Message
-from paramiko.py3compat import byte_chr, byte_ord, byte_mask
 from paramiko.ssh_exception import SSHException
 
 
diff --git a/paramiko/kex_group1.py b/paramiko/kex_group1.py
index 78894566..0dd3c26f 100644
--- a/paramiko/kex_group1.py
+++ b/paramiko/kex_group1.py
@@ -25,9 +25,9 @@ import os
 from hashlib import sha1
 
 from paramiko import util
-from paramiko.common import max_byte, zero_byte
+from paramiko.common import max_byte, zero_byte, byte_chr, byte_mask
 from paramiko.message import Message
-from paramiko.py3compat import byte_chr, long, byte_mask
+from paramiko.py3compat import long
 from paramiko.ssh_exception import SSHException
 
 
diff --git a/paramiko/kex_gss.py b/paramiko/kex_gss.py
index 08e5d787..55f3f5e7 100644
--- a/paramiko/kex_gss.py
+++ b/paramiko/kex_gss.py
@@ -40,10 +40,11 @@ This module provides GSS-API / SSPI Key Exchange as defined in :rfc:`4462`.
 import os
 from hashlib import sha1
 
-from paramiko.common import DEBUG, max_byte, zero_byte
+from paramiko.common import (
+    DEBUG, max_byte, zero_byte, byte_chr, byte_mask, byte_ord,
+)
 from paramiko import util
 from paramiko.message import Message
-from paramiko.py3compat import byte_chr, byte_mask, byte_ord
 from paramiko.ssh_exception import SSHException
 
 
diff --git a/paramiko/message.py b/paramiko/message.py
index 6095d5de..f48e170a 100644
--- a/paramiko/message.py
+++ b/paramiko/message.py
@@ -23,7 +23,7 @@ Implementation of an SSH2 "message".
 import struct
 
 from paramiko import util
-from paramiko.common import zero_byte, max_byte, one_byte, asbytes
+from paramiko.common import zero_byte, max_byte, one_byte
 from paramiko.py3compat import long, BytesIO, u, integer_types
 
 
@@ -270,7 +270,7 @@ class Message(object):
 
         :param str s: string to add
         """
-        s = asbytes(s)
+        s = util.asbytes(s)
         self.add_int(len(s))
         self.packet.write(s)
         return self
diff --git a/paramiko/packet.py b/paramiko/packet.py
index af78e312..914e8971 100644
--- a/paramiko/packet.py
+++ b/paramiko/packet.py
@@ -32,13 +32,14 @@ from paramiko import util
 from paramiko.common import (
     linefeed_byte,
     cr_byte_value,
-    asbytes,
     MSG_NAMES,
     DEBUG,
     xffffffff,
     zero_byte,
+    byte_ord,
 )
-from paramiko.py3compat import u, byte_ord
+from paramiko.py3compat import u
+from paramiko.util import asbytes
 from paramiko.ssh_exception import SSHException, ProxyCommandFailure
 from paramiko.message import Message
 
diff --git a/paramiko/primes.py b/paramiko/primes.py
index 564ab26f..cb7f8ca2 100644
--- a/paramiko/primes.py
+++ b/paramiko/primes.py
@@ -23,7 +23,8 @@ Utility functions for dealing with primes.
 import os
 
 from paramiko import util
-from paramiko.py3compat import byte_mask, long
+from paramiko.common import byte_mask
+from paramiko.py3compat import long
 from paramiko.ssh_exception import SSHException
 
 
diff --git a/paramiko/sftp.py b/paramiko/sftp.py
index cfed9028..2e9dff66 100644
--- a/paramiko/sftp.py
+++ b/paramiko/sftp.py
@@ -21,9 +21,8 @@ import socket
 import struct
 
 from paramiko import util
-from paramiko.common import asbytes, DEBUG
+from paramiko.common import DEBUG, byte_chr, byte_ord
 from paramiko.message import Message
-from paramiko.py3compat import byte_chr, byte_ord
 
 
 (
@@ -191,7 +190,7 @@ class BaseSFTP(object):
         return out
 
     def _send_packet(self, t, packet):
-        packet = asbytes(packet)
+        packet = util.asbytes(packet)
         out = struct.pack(">I", len(packet) + 1) + byte_chr(t) + packet
         if self.ultra_debug:
             self._log(DEBUG, util.format_binary(out, "OUT: "))
diff --git a/paramiko/transport.py b/paramiko/transport.py
index 68cc195d..930ba4d4 100644
--- a/paramiko/transport.py
+++ b/paramiko/transport.py
@@ -86,6 +86,7 @@ from paramiko.common import (
     MSG_NAMES,
     MSG_EXT_INFO,
     cMSG_EXT_INFO,
+    byte_ord,
 )
 from paramiko.compress import ZlibCompressor, ZlibDecompressor
 from paramiko.dsskey import DSSKey
@@ -100,7 +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, long, byte_ord, b, input, PY2
+from paramiko.py3compat import string_types, long, b, input, PY2
 from paramiko.rsakey import RSAKey
 from paramiko.ecdsakey import ECDSAKey
 from paramiko.server import ServerInterface
diff --git a/paramiko/util.py b/paramiko/util.py
index 4267caf1..096b74ff 100644
--- a/paramiko/util.py
+++ b/paramiko/util.py
@@ -29,8 +29,7 @@ import traceback
 import threading
 import logging
 
-from paramiko.common import DEBUG, zero_byte, xffffffff, max_byte
-from paramiko.py3compat import PY2, long, byte_chr, byte_ord, b
+from paramiko.common import DEBUG, zero_byte, xffffffff, max_byte, byte_ord, byte_chr
 from paramiko.config import SSHConfig
 
 
@@ -302,3 +301,24 @@ class ClosingContextManager(object):
 
 def clamp_value(minimum, val, maximum):
     return max(minimum, min(val, maximum))
+
+
+def asbytes(s):
+    """
+    Coerce to bytes if possible or return unchanged.
+    """
+    try:
+        # Attempt to run through our version of b(), which does the Right Thing
+        # for string/unicode/buffer (Py2) or bytes/str (Py3), and raises
+        # TypeError if it's not one of those types.
+        return b(s)
+    except TypeError:
+        try:
+            # If it wasn't a string/byte/buffer type object, try calling an
+            # asbytes() method, which many of our internal classes implement.
+            return s.asbytes()
+        except AttributeError:
+            # Finally, just do nothing & assume this object is sufficiently
+            # byte-y or buffer-y that everything will work out (or that callers
+            # are capable of handling whatever it is.)
+            return s