Linux support

Cargo.toml

@@ -9,6 +9,14 @@ description = "Detect if dark mode or light mode is enabled"
 readme = "README.md"
 
 [dependencies]
+anyhow = "1.0.52"
+
+[target.'cfg(unix)'.dependencies]
+detect-desktop-environment = "0.2.0"
+dconf_rs = "0.3.0"
+dirs = "4.0.0"
+zbus = "2.0.0"
+zvariant = "3.0.0"
 
 [target.'cfg(windows)'.dependencies]
-winreg = "0.8.0"
+winreg = "0.8.0"

src/lib.rs

@@ -23,7 +23,12 @@ mod windows;
 #[cfg(target_os = "windows")]
 use windows as platform;
 
-#[cfg(not(any(target_os = "macos", target_os = "windows")))]
+#[cfg(target_os = "linux")]
+mod linux;
+#[cfg(target_os = "linux")]
+use linux as platform;
+
+#[cfg(not(any(target_os = "macos", target_os = "windows", target_os = "linux")))]
 mod platform {
     pub fn detect() -> crate::Mode {
         Mode::Light
@@ -36,6 +41,16 @@ pub enum Mode {
     Light,
 }
 
+impl Mode {
+    fn from(b: bool) -> Self {
+        if b {
+            Mode::Dark
+        } else {
+            Mode::Light
+        }
+    }
+}
+
 /// Detect if light mode or dark mode is enabled. If the mode can’t be detected, fall back to [`Mode::Light`].
 pub fn detect() -> Mode {
     platform::detect()

src/linux.rs

@@ -0,0 +1,90 @@
+use detect_desktop_environment::DesktopEnvironment;
+use std::path::Path;
+
+use anyhow::{Context, Result};
+use zbus::blocking::Connection;
+use zvariant::Value;
+
+use crate::Mode;
+
+fn get_freedesktop_color_scheme() -> Result<Option<Mode>> {
+    let conn = Connection::session()?;
+    let reply = conn.call_method(
+        Some("org.freedesktop.portal.Desktop"),
+        "/org/freedesktop/portal/desktop",
+        Some("org.freedesktop.portal.Settings"),
+        "Read",
+        &("org.freedesktop.appearance", "color-scheme"),
+    );
+    if let Ok(reply) = &reply {
+        let theme = reply.body::<Value>()?;
+        let theme = theme
+            .downcast::<u32>()
+            .with_context(|| "Failed to parse return value from dbus call to org.freedesktop.appearance color-scheme")?;
+        match theme {
+            1 => Ok(Some(Mode::Dark)),
+            2 => Ok(Some(Mode::Light)),
+            _ => Ok(None),
+        }
+    } else {
+        return Ok(None);
+    }
+}
+
+fn check_file(pattern: &str, path: &Path) -> Mode {
+    if let Ok(content) = std::fs::read_to_string(path) {
+        let theme = content
+            .lines()
+            .filter(|line| line.contains(pattern))
+            .collect::<String>();
+        Mode::from(theme.to_lowercase().contains("dark"))
+    } else {
+        Mode::Light
+    }
+}
+
+fn check_config_file(pattern: &str, path: &str) -> Mode {
+    if let Some(config_dir) = dirs::config_dir() {
+        check_file(pattern, &config_dir.join(path))
+    } else {
+        Mode::Light
+    }
+}
+
+fn check_dconf(pattern: &str) -> Mode {
+    match dconf_rs::get_string(pattern) {
+        Ok(theme) => {
+            if theme.to_lowercase().contains("dark") {
+                Mode::Dark
+            } else {
+                Mode::Light
+            }
+        }
+        Err(_) => Mode::Light,
+    }
+}
+
+pub fn detect() -> Mode {
+    match get_freedesktop_color_scheme() {
+        Ok(mode) => {
+            match mode {
+                Some(mode) => mode,
+                None => match DesktopEnvironment::detect() {
+                    DesktopEnvironment::Cinnamon => {
+                        check_dconf("/org/cinnamon/desktop/interface/gtk-theme")
+                    }
+                    DesktopEnvironment::Gnome => check_dconf("/org/gnome/desktop/interface/gtk-theme"),
+                    DesktopEnvironment::Kde => check_config_file("Name=", "kdeglobals"),
+                    DesktopEnvironment::Mate => check_dconf("/org/mate/desktop/interface/gtk-theme"),
+                    DesktopEnvironment::Unity => check_dconf("/org/gnome/desktop/interface/gtk-theme"),
+                    DesktopEnvironment::Xfce => check_config_file(
+                        "name=\"ThemeName\"",
+                        "xfce4/xfconf/xfce-perchannel-xml/xsettings.xml",
+                    ),
+                    _ => Mode::Light,
+                },
+            }
+        },
+        Err(_) => Mode::Light
+    }
+}

src/macos.rs

@@ -1,22 +1,15 @@
+use crate::Mode;
 use std::process;
 
-fn is_dark_mode_enabled() -> bool {
+pub fn detect() -> Mode {
     if let Ok(output) = process::Command::new("defaults")
         .arg("read")
         .arg("-g")
         .arg("AppleInterfaceStyle")
         .output()
     {
-        output.stdout.starts_with(b"Dark")
+        Mode::from(output.stdout.starts_with(b"Dark"))
     } else {
-        false
-    }
-}
-
-pub fn detect() -> crate::Mode {
-    if is_dark_mode_enabled() {
-        crate::Mode::Dark
-    } else {
-        crate::Mode::Light
+        Mode::Light
     }
 }

src/windows.rs

@@ -1,24 +1,17 @@
+use crate::Mode;
 use winreg::RegKey;
 
-fn is_dark_mode_enabled() -> bool {
+pub fn detect() -> Mode {
     let hkcu = RegKey::predef(winreg::enums::HKEY_CURRENT_USER);
     if let Ok(subkey) =
         hkcu.open_subkey("Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize")
     {
         if let Ok(dword) = subkey.get_value::<u32, _>("AppsUseLightTheme") {
-            (dword == 0)
+            Mode::from(dword == 0)
         } else {
-            false
+            Mode::Light
         }
     } else {
-        false
-    }
-}
-
-pub fn detect() -> crate::Mode {
-    if is_dark_mode_enabled() {
-        crate::Mode::Dark
-    } else {
-        crate::Mode::Light
+        Mode::Light
     }
 }