Split sync and async API

Cargo.toml

@@ -9,6 +9,14 @@ description = "Detect if dark mode or light mode is enabled"
 readme = "README.md"
 build = "build.rs"
 
+[[example]]
+name = "sync"
+path = "examples/sync.rs"
+required-features = ["sync"]
+
+[features]
+sync = ["pollster"]
+
 [dependencies]
 futures = "0.3.30"
 log = "0.4.22"
@@ -18,23 +26,14 @@ tokio = { version = "1.23.0", features = ["full"] }
 
 [target.'cfg(any(target_os = "linux", target_os = "freebsd", target_os = "dragonfly", target_os = "netbsd", target_os = "openbsd"))'.dependencies]
 ashpd = "0.9.1"
-pollster = "0.3.0"
+pollster = { version = "0.3.0", optional = true }
 
 [target.'cfg(windows)'.dependencies]
 winreg = "0.52.0"
 
 [target.'cfg(target_os = "macos")'.dependencies]
-objc2 = "0.5.1"
-objc2-foundation = { version = "0.2.0", features = [
-    "NSArray",
-    "NSObject",
-    "NSString",
-] }
-objc2-app-kit = { version = "0.2.0", features = [
-    "NSAppearance",
-    "NSApplication",
-    "NSResponder",
-] }
+objc2 = "0.5.2"
+objc2-foundation = { version = "0.2.0", features = ["NSObject", "NSString"] }
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 web-sys = { version = "0.3", features = ["MediaQueryList", "Window"] }

examples/async.rs

@@ -0,0 +1,19 @@
+use futures::StreamExt;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    detect().await;
+    subscribe().await;
+    Ok(())
+}
+
+async fn detect() {
+    println!("Current mode: {:?}", dark_light::detect().await);
+}
+
+async fn subscribe() {
+    let mut stream = dark_light::subscribe().await;
+    while let Some(mode) = stream.next().await {
+        println!("System mode changed: {:?}", mode);
+    }
+}

examples/sync.rs

@@ -0,0 +1,16 @@
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    detect();
+    subscribe();
+    Ok(())
+}
+
+fn detect() {
+    println!("Current mode: {:?}", dark_light::detect());
+}
+
+fn subscribe() {
+    let stream = dark_light::subscribe();
+    while let Ok(mode) = stream.recv() {
+        println!("System theme changed: {:?}", mode);
+    }
+}

src/lib.rs

@@ -15,32 +15,12 @@
 //! }
 //! ```
 
+mod mode;
 mod platforms;
-use platforms::platform;
 
-/// Enum representing dark mode, light mode, or unspecified.
-#[derive(Copy, Clone, PartialEq, Eq, Debug)]
-pub enum Mode {
-    /// Dark mode
-    Dark,
-    /// Light mode
-    Light,
-    /// Unspecified
-    Default,
-}
-
-impl Mode {
-    #[allow(dead_code)]
-    fn from_bool(b: bool) -> Self {
-        if b {
-            Mode::Dark
-        } else {
-            Mode::Light
-        }
-    }
-}
+pub use mode::Mode;
 
 /// Detect if light mode or dark mode is enabled. If the mode can’t be detected, fall back to [`Mode::Default`].
-pub use platform::detect::detect;
+pub use platforms::platform::detect::detect;
 /// Notifies the user if the system theme has been changed.
-pub use platform::notify::subscribe;
+pub use platforms::platform::subscribe::subscribe;

src/mode.rs

@@ -0,0 +1,21 @@
+/// Enum representing dark mode, light mode, or unspecified.
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub enum Mode {
+    /// Dark mode
+    Dark,
+    /// Light mode
+    Light,
+    /// Unspecified
+    Default,
+}
+
+impl Mode {
+    #[allow(dead_code)]
+    pub fn from_bool(b: bool) -> Self {
+        if b {
+            Mode::Dark
+        } else {
+            Mode::Light
+        }
+    }
+}

src/platforms/freedesktop/detect.rs

@@ -1,5 +1,11 @@
 use crate::Mode;
 
+#[cfg(feature = "sync")]
 pub fn detect() -> Mode {
     pollster::block_on(super::get_color_scheme())
 }
+
+#[cfg(not(feature = "sync"))]
+pub async fn detect() -> Mode {
+    super::get_color_scheme().await
+}

src/platforms/freedesktop/mod.rs

@@ -1,5 +1,5 @@
 pub mod detect;
-pub mod notify;
+pub mod subscribe;
 
 use crate::Mode;
 

src/platforms/freedesktop/subscribe.rs

@@ -0,0 +1,54 @@
+use std::error::Error;
+
+use ashpd::desktop::settings::Settings;
+use futures::{stream, Stream, StreamExt};
+
+use crate::Mode;
+
+#[cfg(feature = "sync")]
+pub fn subscribe() -> std::sync::mpsc::Receiver<Mode> {
+    let (tx, rx) = std::sync::mpsc::channel();
+
+    std::thread::spawn(move || {
+        pollster::block_on(async {
+            let stream = match color_scheme_stream().await {
+                Ok(stream) => stream,
+                Err(err) => {
+                    log::error!("Failed to subscribe to color scheme changes: {}", err);
+                    Box::pin(Box::new(stream::empty()))
+                }
+            };
+
+            stream
+                .for_each(|mode| {
+                    let _ = tx.send(mode);
+                    async {}
+                })
+                .await;
+        });
+    });
+
+    rx
+}
+
+#[cfg(not(feature = "sync"))]
+pub async fn subscribe() -> impl Stream<Item = Mode> + Send {
+    match color_scheme_stream().await {
+        Ok(stream) => stream,
+        Err(err) => {
+            log::error!("Failed to subscribe to color scheme changes: {}", err);
+            panic!("Failed to subscribe to color scheme changes: {}", err);
+        }
+    }
+}
+
+pub async fn color_scheme_stream() -> Result<impl Stream<Item = Mode> + Send, Box<dyn Error>> {
+    let initial = stream::once(super::get_color_scheme()).boxed();
+    let later_updates = Settings::new()
+        .await?
+        .receive_color_scheme_changed()
+        .await?
+        .map(Mode::from)
+        .boxed();
+    Ok(Box::pin(initial.chain(later_updates)))
+}

src/platforms/macos/detect.rs

@@ -3,45 +3,12 @@
 
 use crate::Mode;
 
-use objc2::sel;
-use objc2_app_kit::{
-    NSAppearance, NSAppearanceNameAccessibilityHighContrastAqua,
-    NSAppearanceNameAccessibilityHighContrastDarkAqua, NSAppearanceNameAqua,
-    NSAppearanceNameDarkAqua, NSApplication,
-};
-use objc2_foundation::{MainThreadMarker, NSArray, NSCopying, NSObjectProtocol};
-
-fn is_dark_mode_enabled() -> bool {
-    // SAFETY: TODO, only perform this function on the main thread.
-    let mtm = unsafe { MainThreadMarker::new_unchecked() };
-
-    unsafe {
-        #[allow(deprecated)]
-        let appearance = NSAppearance::currentAppearance()
-            .unwrap_or_else(|| NSApplication::sharedApplication(mtm).effectiveAppearance());
-
-        let names = NSArray::from_id_slice(&[
-            NSAppearanceNameAqua.copy(),
-            NSAppearanceNameAccessibilityHighContrastAqua.copy(),
-            NSAppearanceNameDarkAqua.copy(),
-            NSAppearanceNameAccessibilityHighContrastDarkAqua.copy(),
-        ]);
-
-        // `bestMatchFromAppearancesWithNames` is only available in macOS 10.14+.
-        // Gracefully handle earlier versions.
-        if !appearance.respondsToSelector(sel!(bestMatchFromAppearancesWithNames:)) {
-            return false;
-        }
-
-        if let Some(style) = appearance.bestMatchFromAppearancesWithNames(&names) {
-            *style == *NSAppearanceNameDarkAqua
-                || *style == *NSAppearanceNameAccessibilityHighContrastDarkAqua
-        } else {
-            false
-        }
-    }
+#[cfg(feature = "sync")]
+pub fn detect() -> crate::Mode {
+    Mode::from_bool(super::is_dark_mode())
 }
 
-pub fn detect() -> crate::Mode {
-    Mode::from_bool(is_dark_mode_enabled())
+#[cfg(not(feature = "sync"))]
+pub async fn detect() -> crate::Mode {
+    Mode::from_bool(super::is_dark_mode())
 }

src/platforms/macos/mod.rs

@@ -1,2 +1,29 @@
 pub mod detect;
-pub mod notify;
+pub mod subscribe;
+
+use objc2::{class, msg_send};
+use objc2_foundation::{NSObject, NSString};
+
+fn is_dark_mode() -> bool {
+    unsafe {
+        let user_defaults: *mut NSObject = msg_send![class!(NSUserDefaults), standardUserDefaults];
+        let apple_domain = NSString::from_str("Apple Global Domain");
+        let dict: *mut NSObject = msg_send![user_defaults, persistentDomainForName:&*apple_domain];
+
+        if !dict.is_null() {
+            let style_key = NSString::from_str("AppleInterfaceStyle");
+            let style: *mut NSObject = msg_send![dict, objectForKey:&*style_key];
+
+            if !style.is_null() {
+                // Compare with "Dark"
+                let dark_str = NSString::from_str("Dark");
+                let is_dark: bool = msg_send![style, isEqualToString:&*dark_str];
+                is_dark
+            } else {
+                false
+            }
+        } else {
+            false
+        }
+    }
+}

src/platforms/macos/subscribe.rs

@@ -0,0 +1,38 @@
+use crate::Mode;
+
+#[cfg(feature = "sync")]
+pub fn subscribe() -> std::sync::mpsc::Receiver<Mode> {
+    let (tx, rx) = std::sync::mpsc::channel();
+    let mut last_mode = crate::detect();
+
+    tx.send(last_mode).unwrap();
+
+    std::thread::spawn(move || loop {
+        let current_mode = crate::detect();
+
+        if current_mode != last_mode {
+            if tx.send(current_mode).is_err() {
+                break;
+            }
+            last_mode = current_mode;
+        }
+    });
+
+    rx
+}
+
+#[cfg(not(feature = "sync"))]
+pub async fn subscribe() -> impl futures::Stream<Item = Mode> {
+    Box::pin(futures::stream::unfold(
+        crate::detect().await,
+        |last_mode| async move {
+            loop {
+                let current_mode = crate::detect().await;
+
+                if current_mode != last_mode {
+                    return Some((current_mode, current_mode));
+                }
+            }
+        },
+    ))
+}