From f01972586624a8240a42daeeb452c19001d78ba4 Mon Sep 17 00:00:00 2001
From: Chris Liechti <cliechti@gmx.net>
Date: Thu, 1 Sep 2016 19:48:03 +0200
Subject: rfc2217: use of Timeout class for modem state timeout

---
 serial/rfc2217.py    | 10 +++++-----
 serial/serialutil.py |  3 +++
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/serial/rfc2217.py b/serial/rfc2217.py
index c46c0de..dee5c2b 100644
--- a/serial/rfc2217.py
+++ b/serial/rfc2217.py
@@ -385,7 +385,7 @@ class Serial(SerialBase):
         self._socket = None
         self._linestate = 0
         self._modemstate = None
-        self._modemstate_expires = 0
+        self._modemstate_timeout = Timeout(-1)
         self._remote_suspend_flow = False
         self._write_lock = None
         self.logger = None
@@ -454,7 +454,7 @@ class Serial(SerialBase):
         # cache for line and modem states that the server sends to us
         self._linestate = 0
         self._modemstate = None
-        self._modemstate_expires = 0
+        self._modemstate_timeout = Timeout(-1)
         # RFC 2217 flow control between server and client
         self._remote_suspend_flow = False
 
@@ -823,7 +823,7 @@ class Serial(SerialBase):
                 if self.logger:
                     self.logger.info("NOTIFY_MODEMSTATE: {}".format(self._modemstate))
                 # update time when we think that a poll would make sense
-                self._modemstate_expires = time.time() + 0.3
+                self._modemstate_timeout.restart(0.3)
             elif suboption[1:2] == FLOWCONTROL_SUSPEND:
                 self._remote_suspend_flow = True
             elif suboption[1:2] == FLOWCONTROL_RESUME:
@@ -894,7 +894,7 @@ class Serial(SerialBase):
         etc.)
         """
         # active modem state polling enabled? is the value fresh enough?
-        if self._poll_modem_state and self._modemstate_expires < time.time():
+        if self._poll_modem_state and self._modemstate_timeout.expired():
             if self.logger:
                 self.logger.debug('polling modem state')
             # when it is older, request an update
@@ -904,7 +904,7 @@ class Serial(SerialBase):
                 time.sleep(0.05)    # prevent 100% CPU load
                 # when expiration time is updated, it means that there is a new
                 # value
-                if self._modemstate_expires > time.time():
+                if not self._modemstate_timeout.expired():
                     break
             else:
                 if self.logger:
diff --git a/serial/serialutil.py b/serial/serialutil.py
index 0b2b9a3..2ed2787 100644
--- a/serial/serialutil.py
+++ b/serial/serialutil.py
@@ -132,6 +132,9 @@ class Timeout(object):
         else:
             return max(0, self.target_time - time.time())
 
+    def restart(self, duration):
+        self.target_time = time.time() + duration
+
 
 class SerialBase(io.RawIOBase):
     """\
-- 
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