Refactor charging function

* Removed the `else` from the top level of the charging() function, the logic is the same but slightly easier to read now.

* Use os.path.exists() in the charging() function before opening the file instead of FileNotFoundError exceptions, makes the function a lot easier to read.

* Close the power_supply_type_path after reading the supply_type as it is not used later.

* Remove `else: continue` from the end of the charging() function for loop, this didn't actually do anything.

I tested the charging() function on my laptop plugged in and plugged out and it is still working as expected with these changes.

auto_cpufreq/core.py

@@ -316,47 +316,41 @@ def charging():
     if len(power_supplies) == 0:
         # nothing found found, so nothing to check
         return True
+
     # we found some power supplies, lets check their state
-    else:
-        for supply in power_supplies:
-            # Check if supply is in ignore list
-            ignore_supply = any(item in supply for item in POWER_SUPPLY_IGNORELIST)
-            # If found in ignore list, skip it.
-            if ignore_supply:
-                continue
+    for supply in power_supplies:
+        # Check if supply is in ignore list
+        ignore_supply = any(item in supply for item in POWER_SUPPLY_IGNORELIST)
+        # If found in ignore list, skip it.
+        if ignore_supply:
+            continue
 
-            try:
-                with open(Path(power_supply_path + supply + "/type")) as f:
-                    supply_type = f.read()[:-1]
-                    if supply_type == "Mains":
-                        # we found an AC
-                        try:
-                            with open(Path(power_supply_path + supply + "/online")) as f:
-                                val = int(f.read()[:-1])
-                                if val == 1:
-                                    # we are definitely charging
-                                    return True
-                        except FileNotFoundError:
-                            # we could not find online, check next item
-                            continue
-                    elif supply_type == "Battery":
-                        # we found a battery, check if its being discharged
-                        try:
-                            with open(Path(power_supply_path + supply + "/status")) as f:
-                                val = str(f.read()[:-1])
-                                if val == "Discharging":
-                                    # we found a discharging battery
-                                    return False
-                        except FileNotFoundError:
-                            # could not find status, check the next item
-                            continue
-                    else:
-                        # continue to next item because current is not
-                        # "Mains" or "Battery"
-                        continue
-            except FileNotFoundError:
-                # could not find type, check the next item
+        power_supply_type_path = Path(power_supply_path + supply + "/type")
+        if not power_supply_type_path.exists():
+            continue
+        with open(power_supply_type_path) as f:
+            supply_type = f.read()[:-1]
+
+        if supply_type == "Mains":
+            # we found an AC
+            power_supply_online_path = Path(power_supply_path + supply + "/online")
+            if not power_supply_online_path.exists():
+                continue
+            with open(power_supply_online_path) as f:
+                val = int(f.read()[:-1])
+                if val == 1:
+                    # we are definitely charging
+                    return True
+        elif supply_type == "Battery":
+            # we found a battery, check if its being discharged
+            power_supply_status_path = Path(power_supply_path + supply + "/status")
+            if not power_supply_status_path.exists():
                 continue
+            with open(power_supply_status_path) as f:
+                val = str(f.read()[:-1])
+                if val == "Discharging":
+                    # we found a discharging battery
+                    return False
 
     # we cannot determine discharging state, assume we are on powercable
     return True