Adds JMIntValidator to ensure exact integer range

Makes BitcoinSatValidator a derived class with a specific
range. Makes all port fields respond correctly to correct
or incorrect entries of port numbers. Changes badly named
'qt' variable to 'sf' in getSettingsFields.

scripts/joinmarket-qt.py

@@ -79,7 +79,7 @@ from jmclient import load_program_config, get_network, update_persist_config,\
 from qtsupport import ScheduleWizard, TumbleRestartWizard, config_tips,\
     config_types, QtHandler, XStream, Buttons, OkButton, CancelButton,\
     PasswordDialog, MyTreeWidget, JMQtMessageBox, BLUE_FG,\
-    donation_more_message, BitcoinAmountEdit
+    donation_more_message, BitcoinAmountEdit, JMIntValidator
 
 from twisted.internet import task
 
@@ -261,27 +261,28 @@ class SettingsTab(QDialog):
             if name in config_types:
                 t = config_types[name]
                 if t == bool:
-                    qt = QCheckBox()
+                    sf = QCheckBox()
                     if val == 'testnet' or val.lower() == 'true':
-                        qt.setChecked(True)
+                        sf.setChecked(True)
                 elif t == 'amount':
-                    qt = BitcoinAmountEdit(val)
+                    sf = BitcoinAmountEdit(val)
                 elif not t:
                     continue
                 else:
-                    qt = QLineEdit(val)
+                    sf = QLineEdit(val)
                     if t == int:
-                        if name in ["rpc_port", "socks5_port", "daemon_port"]:
-                            qt.setValidator(QIntValidator(0, 65535))
+                        if name in ["port", "rpc_port", "socks5_port",
+                                    "daemon_port"]:
+                            sf.setValidator(JMIntValidator(1, 65535))
                         elif name == "tx_fees":
                             # must account for both tx_fees settings type,
                             # and we set upper limit well above default absurd
                             # check just in case a high value is needed:
-                            qt.setValidator(QIntValidator(1, 1000000))
+                            sf.setValidator(JMIntValidator(1, 1000000))
             else:
-                qt = QLineEdit(val)
+                sf = QLineEdit(val)
             label = 'Testnet' if name == 'network' else name
-            results.append((QLabel(label), qt))
+            results.append((QLabel(label), sf))
         return results
 
 class SpendStateMgr(object):

scripts/qtsupport.py

@@ -522,6 +522,22 @@ class MyTreeWidget(QTreeWidget):
 #                    lambda: checkAddress(self, wdgts[0][1].text()))
 #        self.setLayout(layout)
 
+class JMIntValidator(QIntValidator):
+    def __init__(self, minval, maxval):
+        super().__init__(minval, maxval)
+        self.minval = minval
+        self.maxval = maxval
+        self.allowed = set(string.digits)
+
+    def validate(self, arg__1, arg__2):
+        if not arg__1:
+            return QValidator.Intermediate
+        if not set(arg__1) <= self.allowed:
+            return QValidator.Invalid
+        # above guarantees integer
+        if not (int(arg__1) <= self.maxval and int(arg__1) >= self.minval):
+            return QValidator.Invalid
+        return super().validate(arg__1, arg__2)
 
 class BitcoinAmountBTCValidator(QDoubleValidator):
 
@@ -540,20 +556,10 @@ class BitcoinAmountBTCValidator(QDoubleValidator):
         return super().validate(arg__1, arg__2)
 
 
-class BitcoinAmountSatValidator(QIntValidator):
+class BitcoinAmountSatValidator(JMIntValidator):
 
     def __init__(self):
         super().__init__(0, 2147483647)
-        self.setLocale(QtCore.QLocale.c())
-        self.allowed = set(string.digits)
-
-    def validate(self, arg__1, arg__2):
-        if not arg__1:
-            return QValidator.Intermediate
-        if not set(arg__1) <= self.allowed:
-            return QValidator.Invalid
-        return super().validate(arg__1, arg__2)
-
 
 class BitcoinAmountEdit(QWidget):