We support acpibat only in the end, but now we relyin on NetBSD kerne…

…l enum to ensure the data is correct even if someonechange envsys description fields. Extending the code for other battery driver is possible

src/platform/netbsd/device.rs

@@ -10,7 +10,19 @@ use super::utils::{AsResult, GetResult};
 // In other words it is assumed that if a device exposes energy_full is in ampere hours, it  won't
 // report energy_full_design in watt hours.
 
-// Only tested with an acpibat battery.
+// Only acpibat battery driver is supported.
+// https://www.unitedbsd.com/d/1311-battery-data-such-as-vendor-model/25
+
+// https://github.com/NetBSD/src/blob/trunk/sys/dev/acpi/acpi_bat.c#L101
+const ACPIBAT_PRESENT: usize = 0;
+const ACPIBAT_DVOLTAGE: usize = 1;
+const ACPIBAT_VOLTAGE: usize = 2;
+const ACPIBAT_DCAPACITY: usize = 3;
+const ACPIBAT_LFCCAPACITY: usize = 4;
+const ACPIBAT_CAPACITY: usize = 5;
+const ACPIBAT_CHARGERATE: usize = 6;
+const ACPIBAT_DISCHARGERATE: usize = 7;
+const ACPIBAT_CHARGING: usize = 8;
 
 #[derive(Debug, Default)]
 pub struct EnvSysDevice<'a> {
@@ -29,20 +41,21 @@ pub struct EnvSysDevice<'a> {
 
 impl<'a> EnvSysDevice<'a> {
     pub fn new(name: String, sensor: &'a plist::Value) -> Result<Self> {
+        // We only support acpibat driver.
+        // Early check avoid other evaluations.
+        if !name.starts_with("acpibat") {
+            return Err(Error::invalid_data("Not a valid battery"));
+        }
+
         let sensor_slice = sensor.as_rslice()?;
+
         let mut data = Self {
             name,
             ..Self::default()
         };
 
-        let mut status: bool = true;
-
         // Man 4 envsys from NetBSD 10 tells the last one is a "special dictionary"
         // for device properties.
-
-        // We still want our iterator to start from the beginning.
-        // Thus we need to access the last element before iterating.
-
         if sensor_slice
             .last()
             .ok_or(Error::invalid_data("Cannot read sensor property"))?
@@ -53,50 +66,30 @@ impl<'a> EnvSysDevice<'a> {
             return Err(Error::invalid_data("Not a valid battery"));
         }
 
-        // Loop as nothing tells the slice will be populated in order outside of the last one.
-        for attr_res in sensor_slice {
-            match attr_res.get_rstring("description") {
-                Ok("present") => match Self::val_cur_value(attr_res)? {
-                    1 => continue,
-                    _ => return Err(Error::not_found("Battery absent")),
-                },
-                Ok("design voltage") => data.design_voltage = Self::val_cur_value(attr_res)?,
-                Ok("voltage") => data.voltage = Self::val_cur_value(attr_res)?,
-                Ok("design cap") => {
-                    data.energy_full_design = Self::val_cur_value(attr_res)?;
-                    data.eunit = attr_res.get_rstring("type")?;
-                }
-                Ok("last full cap") => data.energy_full = Self::val_cur_value(attr_res)?,
-                Ok("charge") => {
-                    // max-value in the xml is assumed == to last full cap.
-                    if !Self::validate(attr_res)?.get_rbool("want-percentage")? {
-                        return Err(Error::invalid_data("Not a valid battery"));
-                    }
-                    data.energy = attr_res.get_ru64("cur-value")?;
-                }
-                // No validate on charge and discharge rate, we will look at charging to determine that.
-                Ok("charge rate") => {
-                    data.charge_rate = attr_res.get_ri64("cur-value")?;
-                    data.punit = attr_res.get_rstring("type")?;
-                }
-                Ok("discharge rate") => {
-                    data.discharge_rate = attr_res.get_ri64("cur-value")?;
-                    // Sometimes battery can have problems.
-                    // Read that in https://github.com/NetBSD/src/blob/trunk/sys/dev/acpi/acpi_bat.c line 555.
-                    status = attr_res.get_rstring("state")? == "invalid";
-                }
-                Ok("charging") => {
-                    data.charging = Self::validate(attr_res)?.get_ri64("cur-value")?
-                }
-                Ok(_) => continue,
-                Err(e) => match attr_res.get_rdict("device-properties") {
-                    Ok(_) => continue,
-                    Err(_) => return Err(e),
-                },
-            }
+        if Self::val_cur_value(&sensor_slice[ACPIBAT_PRESENT])? != 1 {
+            return Err(Error::not_found("Battery absent"));
+        }
+
+        if !Self::validate(&sensor_slice[ACPIBAT_CAPACITY])?.get_rbool("want-percentage")? {
+            return Err(Error::invalid_data("Not a valid battery"));
         }
 
-        if data.charging == 0 && status {
+        data.design_voltage = Self::val_cur_value(&sensor_slice[ACPIBAT_DVOLTAGE])?;
+        data.voltage = Self::val_cur_value(&sensor_slice[ACPIBAT_VOLTAGE])?;
+        data.energy_full_design = Self::val_cur_value(&sensor_slice[ACPIBAT_DCAPACITY])?;
+        data.energy_full = Self::val_cur_value(&sensor_slice[ACPIBAT_LFCCAPACITY])?;
+        data.energy = Self::val_cur_value(&sensor_slice[ACPIBAT_CAPACITY])?;
+        data.eunit = sensor_slice[ACPIBAT_DCAPACITY].get_rstring("type")?;
+        data.charge_rate = sensor_slice[ACPIBAT_CHARGERATE].get_ri64("cur-value")?;
+        data.discharge_rate = sensor_slice[ACPIBAT_DISCHARGERATE].get_ri64("cur-value")?;
+        data.punit = sensor_slice[ACPIBAT_CHARGERATE].get_rstring("type")?;
+        data.charging = Self::validate(&sensor_slice[ACPIBAT_CHARGING])?.get_ri64("cur-value")?;
+
+        // Sometimes battery can have problems.
+        // Read that in https://github.com/NetBSD/src/blob/trunk/sys/dev/acpi/acpi_bat.c line 555.
+        if data.charging == 0
+            && sensor_slice[ACPIBAT_DISCHARGERATE].get_rstring("state")? == "invalid"
+        {
             data.charging = -1;
         }