Some comments

src/key_utils.rs

@@ -19,6 +19,7 @@ mod tests {
     }
 }
 
+/// Create an input struct from the key code and event
 fn create_input(key_code: u16, event: u32) -> winuser::INPUT {
     let kb_input_u = unsafe {
         let mut kb_input_u = winuser::INPUT_u::default();
@@ -38,6 +39,7 @@ fn create_input(key_code: u16, event: u32) -> winuser::INPUT {
     }
 }
 
+/// Trigger thef list o key events through the Windows api
 pub fn trigger_keys(
     key_codes: &[u16],
     events: &[u32],
@@ -56,6 +58,7 @@ pub fn trigger_keys(
     )
 }
 
+/// Get the speed at which the keyboard repeats a keystroke
 pub fn get_keyboard_speed() -> Result<u32, error_code::ErrorCode<error_code::SystemCategory>> {
     let mut raw_speed = 0u32;
     unsafe {
@@ -79,8 +82,10 @@ pub fn get_max_key_delay() -> Result<u16, error_code::ErrorCode<error_code::Syst
     get_keyboard_speed().map(|raw_speed| raw_speed_to_millis(raw_speed as u8) * 8 / 10)
 }
 
-pub fn is_key_pressed(v_key: i32) -> Result<bool, error_code::ErrorCode<error_code::SystemCategory>> {
+pub fn is_key_pressed(
+    v_key: i32,
+) -> Result<bool, error_code::ErrorCode<error_code::SystemCategory>> {
     // Mask as per https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getasynckeystate
     let mask = 1i16 << 15;
     get_async_key_state(v_key).map(|state| state & mask != 0)
-}
+}

src/lib.rs

@@ -13,23 +13,24 @@ use std::mem;
 use std::sync::{atomic, RwLock};
 use winapi::um::winuser;
 
+use crate::{
+    key_utils::trigger_keys,
+    winapi_functions::{
+        add_clipboard_format_listener, create_window_ex_a, register_class_ex_a, register_hotkey,
+        remove_clipboard_format_listener, sleep, unregister_hotkey,
+    },
+};
+
 const MAX_RETRIES: u8 = 10;
 
+// Have to use global variables to allow access from C callback
 static INTERNAL_UPDATE: atomic::AtomicBool = atomic::AtomicBool::new(false);
 static MAX_HISTORY: atomic::AtomicUsize = atomic::AtomicUsize::new(10);
 
 lazy_static! {
     static ref CB_HISTORY: RwLock<VecDeque<String>> = RwLock::new(VecDeque::new());
 }
 
-use crate::{
-    key_utils::trigger_keys,
-    winapi_functions::{
-        add_clipboard_format_listener, create_window_ex_a, register_class_ex_a, register_hotkey,
-        remove_clipboard_format_listener, sleep, unregister_hotkey,
-    },
-};
-
 extern "system" fn message_watcher_proc(
     h_wnd: *mut winapi::shared::windef::HWND__,
     u_msg: u32,
@@ -135,8 +136,10 @@ extern "system" fn message_watcher_proc(
 }
 
 pub fn run(opts: Opts) {
+    // Move options to global variables
     MAX_HISTORY.store(opts.max_history, atomic::Ordering::Relaxed);
 
+    // Create and register a class
     let class_name = "filo-clipboard_class";
     let window_name = "filo-clipboard";
 
@@ -157,6 +160,8 @@ pub fn run(opts: Opts) {
     };
 
     register_class_ex_a(&lp_wnd_class).unwrap();
+
+    // Create the invisible window
     create_window_ex_a(
         winuser::WS_EX_LEFT,
         class_name,
@@ -173,6 +178,7 @@ pub fn run(opts: Opts) {
     )
     .unwrap();
 
+    // Event loop
     let mut lp_msg = winuser::MSG::default();
     // println!("Ready");
     unsafe {