Remove unsafe from BeetsLibraryCommandExecutor (#23)

Closes #22

Reviewed-on: https://git.wojciechkozlowski.eu/wojtek/musichoard/pulls/23

src/library/beets.rs

@@ -237,13 +237,6 @@ impl LibraryPrivate for BeetsLibrary {
 }
 
 /// Beets library executor that executes beets commands in their own process.
-///
-/// # Safety
-///
-/// The beets executable is not safe to call concurrently for operations on the same
-/// database/library. Therefore, all functions that create a [BeetsLibraryCommandExecutor] or modify
-/// which library it works with are marked unsafe. It is the caller's responsibility to make sure
-/// the library is not being concurrently accessed from anywhere else.
 pub struct BeetsLibraryCommandExecutor {
     bin: String,
     config: Option<PathBuf>,
@@ -251,37 +244,27 @@ pub struct BeetsLibraryCommandExecutor {
 
 impl BeetsLibraryCommandExecutor {
     /// Create a new [BeetsLibraryCommandExecutor] that uses the provided beets executable.
-    ///
-    /// # Safety
-    ///
-    /// The caller must ensure the library is not being concurrently accessed from anywhere else.
-    pub unsafe fn new(bin: &str) -> Self {
+    pub fn new(bin: &str) -> Self {
         BeetsLibraryCommandExecutor {
             bin: bin.to_string(),
             config: None,
         }
     }
 
-    /// Create a new [BeetsLibraryCommandExecutor] that uses the system's default beets executable.
-    ///
-    /// # Safety
-    ///
-    /// The caller must ensure the library is not being concurrently accessed from anywhere else.
-    pub unsafe fn default() -> Self {
-        BeetsLibraryCommandExecutor::new("beet")
-    }
-
     /// Update the configuration file passed to the beets executable.
-    ///
-    /// # Safety
-    ///
-    /// The caller must ensure the library is not being concurrently accessed from anywhere else.
-    pub unsafe fn config(mut self, path: Option<&Path>) -> Self {
+    pub fn config(mut self, path: Option<&Path>) -> Self {
         self.config = path.map(|p| p.to_path_buf());
         self
     }
 }
 
+impl Default for BeetsLibraryCommandExecutor {
+    /// Create a new [BeetsLibraryCommandExecutor] that uses the system's default beets executable.
+    fn default() -> Self {
+        BeetsLibraryCommandExecutor::new("beet")
+    }
+}
+
 impl BeetsLibraryExecutor for BeetsLibraryCommandExecutor {
     fn exec(&mut self, arguments: &[String]) -> Result<Vec<String>, Error> {
         let mut cmd = Command::new(&self.bin);

src/library/mod.rs

@@ -29,6 +29,7 @@ impl<T> QueryOption<T> {
 }
 
 impl<T> Default for QueryOption<T> {
+    /// Create a [QueryOption::None] for type `T`.
     fn default() -> Self {
         Self::None
     }

src/main.rs

@@ -36,9 +36,9 @@ struct Opt {
 fn main() {
     let opt = Opt::from_args();
 
-    let mut beets = BeetsLibrary::new(Box::new(unsafe {
-        BeetsLibraryCommandExecutor::default().config(opt.beets_config_file_path.as_deref())
-    }));
+    let mut beets = BeetsLibrary::new(Box::new(
+        BeetsLibraryCommandExecutor::default().config(opt.beets_config_file_path.as_deref()),
+    ));
 
     let collection = beets
         .list(&Query::new())

tests/library/beets.rs

@@ -16,17 +16,17 @@ use musichoard::{
 use crate::COLLECTION;
 
 static BEETS_EMPTY_CONFIG: Lazy<Arc<Mutex<BeetsLibrary>>> = Lazy::new(|| {
-    Arc::new(Mutex::new(BeetsLibrary::new(Box::new(unsafe {
-        BeetsLibraryCommandExecutor::default()
-    }))))
+    Arc::new(Mutex::new(BeetsLibrary::new(Box::new(
+        BeetsLibraryCommandExecutor::default(),
+    ))))
 });
 
 static BEETS_TEST_CONFIG: Lazy<Arc<Mutex<BeetsLibrary>>> = Lazy::new(|| {
-    Arc::new(Mutex::new(BeetsLibrary::new(Box::new(unsafe {
+    Arc::new(Mutex::new(BeetsLibrary::new(Box::new(
         BeetsLibraryCommandExecutor::default().config(Some(
             &fs::canonicalize("./tests/files/library/config.yml").unwrap(),
-        ))
-    }))))
+        )),
+    ))))
 });
 
 #[test]