From 646151ae61706397a60e22719483add8d1b491f5 Mon Sep 17 00:00:00 2001
From: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
Date: Thu, 12 Nov 2020 09:50:40 -0500
Subject: [PATCH] receiver: reduce unnecessary writes of config file

---
 lib/logitech_receiver/settings.py | 26 ++++++++++++++------------
 lib/solaar/configuration.py       | 12 +++++++-----
 2 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/lib/logitech_receiver/settings.py b/lib/logitech_receiver/settings.py
index c6f14b9a..7e399760 100644
--- a/lib/logitech_receiver/settings.py
+++ b/lib/logitech_receiver/settings.py
@@ -133,14 +133,14 @@ class Setting(object):
                 self._device.persister[self.name] = self._value
             return self._value
 
-    def _pre_write(self):
+    def _pre_write(self, save=True):
         # Remember the value we're trying to set, even if the write fails.
         # This way even if the device is offline or some other error occurs,
         # the last value we've tried to write is remembered in the configuration.
-        if self.persist and self._device.persister:
+        if self.persist and self._device.persister and save:
             self._device.persister[self.name] = self._value
 
-    def write(self, value):
+    def write(self, value, save=True):
         assert hasattr(self, '_value')
         assert hasattr(self, '_device')
         assert value is not None
@@ -149,8 +149,9 @@ class Setting(object):
             _log.debug('%s: settings write %r to %s', self.name, value, self._device)
 
         if self._device.online:
-            self._value = value
-            self._pre_write()
+            if self._value != value:
+                self._value = value
+                self._pre_write(save)
 
             current_value = None
             if self._validator.needs_current_value:
@@ -178,7 +179,7 @@ class Setting(object):
 
         value = self.read(self.persist)  # Don't use persisted value if setting doesn't persist
         if self.persist and value is not None:  # If setting doesn't persist no need to write value just read
-            self.write(value)
+            self.write(value, save=False)
 
     def __str__(self):
         if hasattr(self, '_value'):
@@ -239,7 +240,7 @@ class Settings(Setting):
                 self._device.persister[self.name] = self._value
             return self._value[str(int(key))]
 
-    def write(self, map):
+    def write(self, map, save=True):
         assert hasattr(self, '_value')
         assert hasattr(self, '_device')
         assert map is not None
@@ -249,7 +250,7 @@ class Settings(Setting):
 
         if self._device.online:
             self._value = map
-            self._pre_write()
+            self._pre_write(save)
             for key, value in map.items():
                 data_bytes = self._validator.prepare_write(int(key), value)
                 if data_bytes is not None:
@@ -272,6 +273,7 @@ class Settings(Setting):
         if self._device.online:
             try:
                 data_bytes = self._validator.prepare_write(int(key), value)
+                # always need to write to configuration because dictionary is shared and could have changed
                 self._value[str(key)] = value
                 self._pre_write()
             except ValueError:
@@ -339,7 +341,7 @@ class LongSettings(Setting):
                 self._device.persister[self.name] = self._value
             return self._value[str(int(item))]
 
-    def write(self, map):
+    def write(self, map, save=True):
         assert hasattr(self, '_value')
         assert hasattr(self, '_device')
         assert map is not None
@@ -348,7 +350,7 @@ class LongSettings(Setting):
             _log.debug('%s: settings write %r to %s', self.name, map, self._device)
         if self._device.online:
             self._value = map
-            self._pre_write()
+            self._pre_write(save)
             for item, value in map.items():
                 data_bytes_list = self._validator.prepare_write(self._value)
                 if data_bytes_list is not None:
@@ -437,7 +439,7 @@ class BitFieldSetting(Setting):
     def _do_read_key(self, key):
         return self._rw.read(self._device, key)
 
-    def write(self, map):
+    def write(self, map, save=True):
         assert hasattr(self, '_value')
         assert hasattr(self, '_device')
         assert map is not None
@@ -446,7 +448,7 @@ class BitFieldSetting(Setting):
             _log.debug('%s: settings write %r to %s', self.name, map, self._device)
         if self._device.online:
             self._value = map
-            self._pre_write()
+            self._pre_write(save)
             data_bytes = self._validator.prepare_write(self._value)
             if data_bytes is not None:
                 if _log.isEnabledFor(_DEBUG):
diff --git a/lib/solaar/configuration.py b/lib/solaar/configuration.py
index a79c4950..fa15190a 100644
--- a/lib/solaar/configuration.py
+++ b/lib/solaar/configuration.py
@@ -101,7 +101,8 @@ def _cleanup(d):
 class _DeviceEntry(dict):
     def __init__(self, device, **kwargs):
         super(_DeviceEntry, self).__init__(**kwargs)
-        self[_KEY_NAME] = device.name
+        if self.get(_KEY_NAME) != device.name:
+            self[_KEY_NAME] = device.name
         self.update(device)
 
     def __setitem__(self, key, value):
@@ -109,9 +110,9 @@ class _DeviceEntry(dict):
         save()
 
     def update(self, device):
-        if device.modelId:
+        if device.modelId and device.modelId != self.get(_KEY_MODEL_ID):
             self[_KEY_MODEL_ID] = device.modelId
-        if device.unitId:
+        if device.unitId and device.unitId != self.get(_KEY_UNIT_ID):
             self[_KEY_UNIT_ID] = device.unitId
 
     def get_sensitivity(self, name):
@@ -119,8 +120,9 @@ class _DeviceEntry(dict):
 
     def set_sensitivity(self, name, value):
         sensitives = self.get('_sensitive', {})
-        sensitives[name] = value
-        self['_sensitive'] = sensitives
+        if sensitives.get(name) != value:
+            sensitives[name] = value
+            self['_sensitive'] = sensitives
 
 
 def persister(device):