Handling the ENODEV errors for Linux (closes #28)

CHANGELOG.md

@@ -5,6 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.7.3] - 2019-05-30
+### Fixed
+- `ENODEV` errors for Linux are now handled the same as `ENOENT` [#28](https://github.com/svartalf/rust-battery/issues/28)
+
+### Changed
+- Relaxing `uom` dependency version to `^0.23` for `battery` crate
+- Relaxing `libc` dependency version to `^0.2` for `battery-ffi` crate
+
 ## [0.7.2] - 2019-05-21
 ### Fixed
 - `Battery::state_of_health` and `Battery::state_of_charge` are always returning values in `0.0 ≤ x ≤ 1.0` interval

README.md

@@ -3,7 +3,8 @@
 [![Latest Version](https://img.shields.io/crates/v/battery.svg)](https://crates.io/crates/battery)
 [![Latest Version](https://docs.rs/battery/badge.svg)](https://docs.rs/battery)
 [![Build Status](https://travis-ci.org/svartalf/rust-battery.svg?branch=master)](https://travis-ci.org/svartalf/rust-battery)
-[![dependency status](https://deps.rs/crate/battery/0.7.2/status.svg)](https://deps.rs/crate/battery/0.7.2)
+[![dependency status](https://deps.rs/crate/battery/0.7.3/status.svg)](https://deps.rs/crate/battery/0.7.3)
+[![Minimum rustc version](https://img.shields.io/badge/rustc-1.31+-yellow.svg)](https://github.com/rust-random/rand#rust-version-requirements)
 ![Apache 2.0 OR MIT licensed](https://img.shields.io/badge/license-Apache2.0%2FMIT-blue.svg)
 [![backers](https://opencollective.com/rust-battery/tiers/backer/badge.svg?label=backer&color=brightgreen)](https://opencollective.com/rust-battery)
 
@@ -24,10 +25,14 @@ recalculated as necessary to be returned [SI measurement units](https://www.bipm
 
 Until `1.0.0` version API might change in any moment, be careful.
 
+# Rust version requirements
+
+Both `battery` and `battery-ffi` crates are requiring at least Rustc version **1.31** or greater.
+
 ## Examples
 
 See full-featured `battop` TUI application at [GitHub](https://github.com/svartalf/rust-battop/)
-or at [crates.io](https://crates.rs/crate/battop).
+or at [crates.io](https://crates.io/crate/battop).
 
 For a simple example check `battery/examples/simple.rs` in the [repository](https://github.com/svartalf/rust-battery/blob/master/battery/examples/simple.rs)
 

battery-ffi/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "battery-ffi"
-version = "0.7.2" # remember to update html_root_url
+version = "0.7.3" # remember to update html_root_url
 authors = ["svartalf <[email protected]>"]
 edition = "2018"
 description = "FFI bindings for battery crate"
@@ -24,11 +24,11 @@ crate-type = ["cdylib"]
 default = ["cbindgen"]
 
 [dependencies.battery]
-version = "0.7.1"
+version = "0.7.3"
 path = "../battery"
 
 [dependencies]
-libc = "0.2.51"
+libc = "^0.2"
 
 [build-dependencies]
 cbindgen = { version = "0.8.0", optional = true }

battery-ffi/src/lib.rs

@@ -40,7 +40,7 @@
 //!
 //! Also, check the `examples/` directory in the repository for examples with C and Python.
 
-#![doc(html_root_url = "https://docs.rs/battery-ffi/0.7.2")]
+#![doc(html_root_url = "https://docs.rs/battery-ffi/0.7.3")]
 
 // cbindgen==0.8.0 fails to export typedefs for opaque pointers
 // from the battery crate, if this line is missing

battery/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "battery"
-version = "0.7.2" # remember to update html_root_url
+version = "0.7.3" # remember to update html_root_url
 authors = ["svartalf <[email protected]>"]
 edition = "2018"
 description = "Cross-platform information about batteries"
@@ -19,7 +19,10 @@ is-it-maintained-open-issues = { repository = "svartalf/rust-battery" }
 [dependencies]
 cfg-if = "0.1"
 num-traits = { version = "0.2", default_features = false }
-uom = { version = "0.23.0", features = ["autoconvert", "f32", "si"] }
+uom = { version = "^0.23", features = ["autoconvert", "f32", "si"] }
+
+[dev-dependencies]
+tempfile = "^3.0"
 
 [target.'cfg(target_os = "linux")'.dependencies]
 lazycell = "1.2.1"

battery/src/lib.rs

@@ -13,14 +13,17 @@
 //!
 //! ## Examples
 //!
-//! For a quick example see [Manager](struct.Manager.html) type or `simple.rs` file in the `examples/` folder.
+//! For a quick example see the [Manager](struct.Manager.html) type documentation
+//! or [`simple.rs`](https://github.com/svartalf/rust-battery/blob/master/battery/examples/simple.rs)
+//! file in the `examples/` folder.
 //!
-//! For a real-live example see [battop](https://crates.io/crates/battop) crate.
+//! [battop](https://crates.io/crates/battop) crate is using this library as a knowledge source,
+//! so check it out too for a real-life example.
 
 #![deny(unused)]
 #![deny(unstable_features)]
 #![deny(bare_trait_objects)]
-#![doc(html_root_url = "https://docs.rs/battery/0.7.2")]
+#![doc(html_root_url = "https://docs.rs/battery/0.7.3")]
 
 #[macro_use]
 extern crate cfg_if;

battery/src/platform/linux/mod.rs

@@ -6,3 +6,6 @@ mod sysfs;
 pub use self::device::SysFsDevice;
 pub use self::iterator::SysFsIterator;
 pub use self::manager::SysFsManager;
+
+#[cfg(test)]
+mod tests;

battery/src/platform/linux/sysfs/fs.rs

@@ -8,6 +8,10 @@ use super::{Scope, Type};
 use crate::units::{ElectricCharge, ElectricPotential, Energy, Power};
 use crate::Result;
 
+// From the `errno.h`.
+// Easier than building whole `libc` dep.
+const ENODEV: i32 = 19;
+
 /// Read µWh value from the `energy_` file and convert into `Energy` type.
 pub fn energy<T: AsRef<Path>>(path: T) -> Result<Option<Energy>> {
     let path = path.as_ref();
@@ -87,19 +91,26 @@ pub fn scope<T: AsRef<Path>>(path: T) -> Result<Scope> {
 ///
 /// Ok(Some(value)) - file was read properly
 /// Ok(None) - file is missing
-/// Err(_) - unable to access file for some reasons (except `NotFound`)
+/// Err(_) - unable to access file for some reasons (except `NotFound` and `ENODEV`)
 pub fn get_string<T: AsRef<Path>>(path: T) -> Result<Option<String>> {
     match read_to_string(path) {
-        Ok(ref content) => {
-            // TODO: Get rid of allocation, read file only until `\n` comes
-            let trimmed = content.trim();
-            if trimmed.starts_with('\0') {
+        Ok(mut content) => {
+            if content.starts_with('\0') {
                 Err(io::Error::from(io::ErrorKind::InvalidData).into())
             } else {
-                Ok(Some(trimmed.to_string()))
+                // In-place trim
+                if content.ends_with('\n') {
+                    content.truncate(content.len() - 1);
+                }
+
+                Ok(Some(content))
             }
         }
         Err(ref e) if e.kind() == io::ErrorKind::NotFound => Ok(None),
+        // Some drivers are creating the files, but attempt to read them
+        // fails with a `ENODEV` error.
+        // See https://github.com/svartalf/rust-battery/issues/28
+        Err(ref e) if e.raw_os_error() == Some(ENODEV) => Ok(None),
         Err(e) => Err(e.into()),
     }
 }

battery/src/platform/linux/tests/issue_28.rs

@@ -0,0 +1,38 @@
+use std::fs;
+
+use super::super::SysFsDevice;
+
+// https://github.com/svartalf/rust-battery/issues/28
+//
+// This test is not actually covers the `ENODEV` case,
+// but it would be nice to have some test cases,
+// especially when people are so gracious to provide
+// the test data.
+#[test]
+fn test_issue_28() {
+    let root = sysfs_test_suite!(
+        "charge_full_design" => 3600000,
+        "serial_number" => "41167",
+        "technology" => "Li-ion",
+        "charge_now" => 725000,
+        "present" => 1,
+        "manufacturer" => "Hewlett-Packard",
+        "type" => "Battery",
+        "charge_full" => 3424000,
+        "capacity" => 21,
+        "cycle_count" => 0,
+        "voltage_now" => 10663000,
+        "status" => "Discharging",
+        "alarm" => 340000,
+        "model_name" => "PABAS0241231",
+        "voltage_min_design" => 11400000,
+        "capacity_level" => "Normal"
+    );
+
+    let path = root.into_path();
+    let device = SysFsDevice::try_from(path.clone());
+
+    assert!(device.is_ok());
+
+    fs::remove_dir_all(path).unwrap();
+}

battery/src/platform/linux/tests/mod.rs

@@ -0,0 +1,22 @@
+/// This macro generates the bunch of files representing the
+/// `/sys/class/power_supply/{name}/*` directory contents.
+macro_rules! sysfs_test_suite {
+    ( $( $name:expr => $value:expr ),* ) => {{
+        use ::std::io::Write as _;
+
+        let root = tempfile::tempdir().unwrap();
+
+        $(
+            let mut file = ::std::fs::OpenOptions::new()
+                .write(true)
+                .create_new(true)
+                .open(root.path().join($name))
+                .unwrap();
+            file.write_fmt(format_args!("{}\n", $value)).unwrap();
+        )*
+
+        root
+    }};
+}
+
+mod issue_28;

battery/src/types/battery.rs

@@ -10,7 +10,7 @@ use crate::{State, Technology};
 ///
 /// Consequent calls of the same method will return the same value.\
 /// See the [Manager::refresh](struct.Manager.html#method.refresh) method,
-/// which can be used to update information holded in the current `Battery`.
+/// which can be used to update information hold in the current `Battery`.
 ///
 /// Almost all methods are returning values in the [SI measurement units](https://www.bipm.org/en/measurement-units/),
 /// represented as a units from the [uom](https://crates.io/crates/uom) crate.\

ci/script.sh

@@ -4,7 +4,7 @@ set -ex
 
 cross build --target=${TARGET}
 
-if [ "${TARGET}" = "i686-unknown-freebsd" ] || [ "${TARGET}" = "x86_64-unknown-freebsd" ]; then
+if [[ "${TARGET}" = "i686-unknown-freebsd" ]] || [[ "${TARGET}" = "x86_64-unknown-freebsd" ]]; then
     echo "'cross test' command is not available for '${TARGET}' target"
 else
     cross test --target=${TARGET}