Add preferences abstraction

system-configuration/src/lib.rs

@@ -24,3 +24,4 @@ extern crate core_foundation;
 extern crate system_configuration_sys;
 
 pub mod dynamic_store;
+pub mod preferences;

system-configuration/src/preferences.rs

@@ -0,0 +1,89 @@
+// Copyright 2017 Amagicom AB.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Bindings to [`SCPreferences`].
+//!
+//! See the examples directory for examples how to use this module.
+//!
+//! [`SCPreferences`]: https://developer.apple.com/documentation/systemconfiguration/scpreferences-ft8
+
+
+use core_foundation::base::{CFAllocator, TCFType};
+use core_foundation::string::CFString;
+
+pub use system_configuration_sys::preferences::*;
+
+use std::ptr;
+
+
+declare_TCFType!{
+    /// The handle to an open preferences session for accessing system configuration preferences.
+    SCPreferences, SCPreferencesRef
+}
+
+impl_TCFType!(SCPreferences, SCPreferencesRef, SCPreferencesGetTypeID);
+
+
+impl SCPreferences {
+    /// Initiates access to the default system preferences using the default allocator.
+    pub fn default(calling_process_name: &CFString) -> Self {
+        Self::new(None, calling_process_name, None)
+    }
+
+    /// Initiates access to the given (`prefs_id`) group of configuration preferences using the
+    /// default allocator. To access the default system preferences, use the [`default`]
+    /// constructor.
+    ///
+    /// [`default`]: #method.default
+    pub fn group(calling_process_name: &CFString, prefs_id: &CFString) -> Self {
+        Self::new(None, calling_process_name, Some(prefs_id))
+    }
+
+    /// Initiates access to the per-system set of configuration preferences with a given
+    /// allocator and preference group to access. See the underlying [SCPreferencesCreate] function
+    /// documentation for details. Use the helper constructors [`default`] and [`group`] to easier
+    /// create an instance using the default allocator.
+    ///
+    /// [SCPreferencesCreate]: https://developer.apple.com/documentation/systemconfiguration/1516807-scpreferencescreate?language=objc
+    /// [`default`]: #method.default
+    /// [`group`]: #method.group
+    pub fn new(
+        allocator: Option<&CFAllocator>,
+        calling_process_name: &CFString,
+        prefs_id: Option<&CFString>,
+    ) -> Self {
+        let allocator_ref = match allocator {
+            Some(allocator) => allocator.as_concrete_TypeRef(),
+            None => ptr::null(),
+        };
+        let prefs_id_ref = match prefs_id {
+            Some(prefs_id) => prefs_id.as_concrete_TypeRef(),
+            None => ptr::null(),
+        };
+
+        unsafe {
+            SCPreferences::wrap_under_create_rule(SCPreferencesCreate(
+                allocator_ref,
+                calling_process_name.as_concrete_TypeRef(),
+                prefs_id_ref,
+            ))
+        }
+    }
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn retain_count() {
+        let preferences = SCPreferences::default(&CFString::new("test"));
+        assert_eq!(preferences.retain_count(), 1);
+    }
+}