python/qemu: Delint the qmp module

This clean up the pylint-3 report on qmp:

************* Module qemu.qmp
python/qemu/qmp.py:1:0: C0111: Missing module docstring (missing-docstring)
python/qemu/qmp.py:17:0: C0111: Missing class docstring (missing-docstring)
python/qemu/qmp.py:21:0: C0111: Missing class docstring (missing-docstring)
python/qemu/qmp.py:25:0: C0111: Missing class docstring (missing-docstring)
python/qemu/qmp.py:29:0: C0111: Missing class docstring (missing-docstring)
python/qemu/qmp.py:33:0: C0111: Missing class docstring (missing-docstring)
python/qemu/qmp.py:33:0: R0205: Class 'QEMUMonitorProtocol' inherits from object, can be safely removed from bases in python3 (useless-object-inheritance)
python/qemu/qmp.py:80:4: R1710: Either all return statements in a function should return an expression, or none of them should. (inconsistent-return-statements)
python/qemu/qmp.py:131:4: R1710: Either all return statements in a function should return an expression, or none of them should. (inconsistent-return-statements)
python/qemu/qmp.py:159:4: R1710: Either all return statements in a function should return an expression, or none of them should. (inconsistent-return-statements)
python/qemu/qmp.py:245:4: C0111: Missing method docstring (missing-docstring)
python/qemu/qmp.py:249:4: C0111: Missing method docstring (missing-docstring)
python/qemu/qmp.py:252:4: C0111: Missing method docstring (missing-docstring)
python/qemu/qmp.py:255:4: C0111: Missing method docstring (missing-docstring)

Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20191227134101.244496-3-wainersm@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>

1 files changed, 41 insertions, 10 deletions

diff --git a/python/qemu/qmp.py b/python/qemu/qmp.py
index 8c6c9847d0..f4e04a6683 100644
--- a/python/qemu/qmp.py
+++ b/python/qemu/qmp.py
@@ -1,5 +1,4 @@
-# QEMU Monitor Protocol Python class
-#
+""" QEMU Monitor Protocol Python class """
 # Copyright (C) 2009, 2010 Red Hat Inc.
 #
 # Authors:
@@ -15,22 +14,34 @@ import logging
 
 
 class QMPError(Exception):
-    pass
+    """
+    QMP base exception
+    """
 
 
 class QMPConnectError(QMPError):
-    pass
+    """
+    QMP connection exception
+    """
 
 
 class QMPCapabilitiesError(QMPError):
-    pass
+    """
+    QMP negotiate capabilities exception
+    """
 
 
 class QMPTimeoutError(QMPError):
-    pass
+    """
+    QMP timeout exception
+    """
 
 
-class QEMUMonitorProtocol(object):
+class QEMUMonitorProtocol:
+    """
+    Provide an API to connect to QEMU via QEMU Monitor Protocol (QMP) and then
+    allow to handle commands and events.
+    """
 
     #: Logger object for debugging messages
     logger = logging.getLogger('QMP')
@@ -81,7 +92,7 @@ class QEMUMonitorProtocol(object):
         while True:
             data = self.__sockfile.readline()
             if not data:
-                return
+                return None
             resp = json.loads(data)
             if 'event' in resp:
                 self.logger.debug("<<< %s", resp)
@@ -132,7 +143,7 @@ class QEMUMonitorProtocol(object):
         """
         Connect to the QMP Monitor and perform capabilities negotiation.
 
-        @return QMP greeting dict
+        @return QMP greeting dict, or None if negotiate is false
         @raise OSError on socket connection errors
         @raise QMPConnectError if the greeting is not received
         @raise QMPCapabilitiesError if fails to negotiate capabilities
@@ -141,6 +152,7 @@ class QEMUMonitorProtocol(object):
         self.__sockfile = self.__sock.makefile()
         if negotiate:
             return self.__negotiate_capabilities()
+        return None
 
     def accept(self):
         """
@@ -169,7 +181,7 @@ class QEMUMonitorProtocol(object):
             self.__sock.sendall(json.dumps(qmp_cmd).encode('utf-8'))
         except OSError as err:
             if err.errno == errno.EPIPE:
-                return
+                return None
             raise err
         resp = self.__json_read()
         self.logger.debug("<<< %s", resp)
@@ -243,14 +255,33 @@ class QEMUMonitorProtocol(object):
         self.__events = []
 
     def close(self):
+        """
+        Close the socket and socket file.
+        """
         self.__sock.close()
         self.__sockfile.close()
 
     def settimeout(self, timeout):
+        """
+        Set the socket timeout.
+
+        @param timeout (float): timeout in seconds, or None.
+        @note This is a wrap around socket.settimeout
+        """
         self.__sock.settimeout(timeout)
 
     def get_sock_fd(self):
+        """
+        Get the socket file descriptor.
+
+        @return The file descriptor number.
+        """
         return self.__sock.fileno()
 
     def is_scm_available(self):
+        """
+        Check if the socket allows for SCM_RIGHTS.
+
+        @return True if SCM_RIGHTS is available, otherwise False.
+        """
         return self.__sock.family == socket.AF_UNIX