Improvements for api

Better error handling, focused on using in other crates

Cargo.toml

@@ -6,7 +6,5 @@ edition = "2021"
 [profile.release]
 strip = true
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
 [dependencies]
 x11 = { version = "2.20.0", features = ["xss", "xlib"] }

src/lib.rs

@@ -1,7 +1,7 @@
 mod xinterface {
+    use std::ffi::c_void;
     use x11::xlib::{XCloseDisplay, XDefaultRootWindow, XFree, XOpenDisplay};
     use x11::xss::{XScreenSaverAllocInfo, XScreenSaverQueryExtension, XScreenSaverQueryInfo};
-    use std::ffi::c_void;
 
     pub struct Display {
         display_ptr: *mut x11::xlib::Display,
@@ -24,11 +24,8 @@ mod xinterface {
             let mut event_basep: i32 = 0;
             let mut error_basep: i32 = 0;
             unsafe {
-                XScreenSaverQueryExtension(
+                XScreenSaverQueryExtension(self.display_ptr, &mut event_basep, &mut error_basep)
-                    self.display_ptr,
+                    != 0
-                    &mut event_basep,
-                    &mut error_basep
-                ) != 0
             }
         }
 
@@ -79,21 +76,32 @@ mod xinterface {
 
 use xinterface::Display;
 
-pub fn get_idle_time() -> u64 {
+pub enum Error {
-    let display = Display::open().unwrap_or_else(|_| {
+    CannotOpenDisplay,
-        println!("Cannot open display");
+    NoScreenSaverExtension,
-        std::process::exit(1);
+    CannotGetScreenSaverinfo,
-    });
+}
+
+impl Error {
+    pub fn message(&self) -> &'static str {
+        match self {
+            Self::CannotOpenDisplay => "Cannot open display",
+            Self::NoScreenSaverExtension => "Screen doesn't have screen saver extension",
+            Self::CannotGetScreenSaverinfo => "Cannot get screen saver info",
+        }
+    }
+}
+
+pub fn get_idle_time() -> Result<u64, Error> {
+    let display = Display::open().or(Err(Error::CannotOpenDisplay))?;
 
     if !display.has_screen_saver_extesnsion() {
-        println!("Screen doesn't have screen saver extension");
+        return Err(Error::NoScreenSaverExtension);
-        std::process::exit(1);
     }
 
-    let screen_saver_info = display.get_screen_saver_info().unwrap_or_else(|_| {
+    let screen_saver_info = display
-        println!("Cannot get screen saver info");
+        .get_screen_saver_info()
-        std::process::exit(1);
+        .or(Err(Error::CannotGetScreenSaverinfo))?;
-    });
 
-    screen_saver_info.idle_time()
+    Ok(screen_saver_info.idle_time())
 }

src/main.rs

@@ -1,3 +1,11 @@
-fn main() {
+fn error(error: rs_idle::Error) -> ! {
-    println!("{}", rs_idle::get_idle_time());
+    println!("{}", error.message());
+    std::process::exit(1);
+}
+
+fn main() {
+    println!(
+        "{}",
+        rs_idle::get_idle_time().unwrap_or_else(|e| { error(e) })
+    );
 }