1 files changed, 82 insertions, 0 deletions
diff --git a/sound_card_init/dsm/src/utils.rs b/sound_card_init/dsm/src/utils.rs
new file mode 100644
index 00000000..64f6c972
--- /dev/null
+++ b/sound_card_init/dsm/src/utils.rs
@@ -0,0 +1,82 @@
+// Copyright 2020 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//! It contains common utils shared within sound_card_init.
+#![deny(missing_docs)]
+
+use std::fs::File;
+use std::io::{prelude::*, BufReader, BufWriter};
+use std::path::PathBuf;
+use std::time::Duration;
+
+use crate::datastore::Datastore;
+use crate::error::{Error, Result};
+
+fn duration_from_file(path: &PathBuf) -> Result<Duration> {
+    let reader =
+        BufReader::new(File::open(&path).map_err(|e| Error::FileIOFailed(path.clone(), e))?);
+    serde_yaml::from_reader(reader).map_err(|e| Error::SerdeError(path.clone(), e))
+}
+
+/// The utils to parse CRAS shutdown time file.
+pub mod shutdown_time {
+    use super::*;
+    // The path of CRAS shutdown time file.
+    const SHUTDOWN_TIME_FILE: &str = "/var/lib/cras/stop";
+
+    /// Reads the unix time from CRAS shutdown time file.
+    pub fn from_file() -> Result<Duration> {
+        duration_from_file(&PathBuf::from(SHUTDOWN_TIME_FILE))
+    }
+}
+
+/// The utils to create and parse sound_card_init run time file.
+pub mod run_time {
+    use std::time::SystemTime;
+
+    use super::*;
+    // The filename of sound_card_init run time file.
+    const RUN_TIME_FILE: &str = "run";
+
+    /// Returns the sound_card_init run time file existence.
+    pub fn exists(snd_card: &str) -> bool {
+        run_time_file(snd_card).exists()
+    }
+
+    /// Reads the unix time from sound_card_init run time file.
+    pub fn from_file(snd_card: &str) -> Result<Duration> {
+        duration_from_file(&run_time_file(snd_card))
+    }
+
+    /// Saves the current unix time to sound_card_init run time file.
+    pub fn now_to_file(snd_card: &str) -> Result<()> {
+        match SystemTime::now().duration_since(SystemTime::UNIX_EPOCH) {
+            Ok(t) => to_file(snd_card, t),
+            Err(e) => Err(Error::SystemTimeError(e)),
+        }
+    }
+
+    /// Saves the unix time to sound_card_init run time file.
+    pub fn to_file(snd_card: &str, duration: Duration) -> Result<()> {
+        let path = run_time_file(snd_card);
+        let mut writer =
+            BufWriter::new(File::create(&path).map_err(|e| Error::FileIOFailed(path.clone(), e))?);
+        writer
+            .write_all(
+                serde_yaml::to_string(&duration)
+                    .map_err(|e| Error::SerdeError(path.clone(), e))?
+                    .as_bytes(),
+            )
+            .map_err(|e| Error::FileIOFailed(path.clone(), e))?;
+        writer
+            .flush()
+            .map_err(|e| Error::FileIOFailed(path.clone(), e))?;
+        Ok(())
+    }
+
+    fn run_time_file(snd_card: &str) -> PathBuf {
+        PathBuf::from(Datastore::DATASTORE_DIR)
+            .join(snd_card)
+            .join(RUN_TIME_FILE)
+    }
+}