From 53eef3ce7b475960d98f7e580ccb88d52e06f592 Mon Sep 17 00:00:00 2001
From: Federico Terzi <federico-terzi@users.noreply.github.com>
Date: Sun, 22 Aug 2021 21:45:49 +0200
Subject: [PATCH] fix(detect): exclude software-generated events by default on
 Windows to avoid reading back espanso's events

---
 espanso-detect/src/lib.rs           | 11 +++++++++--
 espanso-detect/src/win32/mod.rs     | 23 ++++++++++++++++++++++-
 espanso-detect/src/win32/native.cpp |  2 ++
 espanso-detect/src/win32/native.h   |  6 ++++++
 4 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/espanso-detect/src/lib.rs b/espanso-detect/src/lib.rs
index 60ad3f3..636caf0 100644
--- a/espanso-detect/src/lib.rs
+++ b/espanso-detect/src/lib.rs
@@ -60,6 +60,12 @@ pub struct SourceCreationOptions {
   // List of global hotkeys the detection module has to register
   // NOTE: Hotkeys don't work under the EVDEV backend yet (Wayland)
   pub hotkeys: Vec<HotKey>,
+
+  // If true, filter out keyboard events without an explicit HID device source on Windows.
+  // This is needed to filter out the software-generated events, including
+  // those from espanso, but might need to be disabled when using some software-level keyboards.
+  // Disabling this option might conflict with the undo feature.
+  pub win32_exclude_orphan_events: bool,
 }
 
 // This struct identifies the keyboard layout that
@@ -80,6 +86,7 @@ impl Default for SourceCreationOptions {
       use_evdev: false,
       evdev_keyboard_rmlvo: None,
       hotkeys: Vec::new(),
+      win32_exclude_orphan_events: true,
     }
   }
 }
@@ -87,7 +94,7 @@ impl Default for SourceCreationOptions {
 #[cfg(target_os = "windows")]
 pub fn get_source(options: SourceCreationOptions) -> Result<Box<dyn Source>> {
   info!("using Win32Source");
-  Ok(Box::new(win32::Win32Source::new(&options.hotkeys)))
+  Ok(Box::new(win32::Win32Source::new(&options.hotkeys, options.win32_exclude_orphan_events)))
 }
 
 #[cfg(target_os = "macos")]
@@ -115,4 +122,4 @@ pub fn get_source(options: SourceCreationOptions) -> Result<Box<dyn Source>> {
   Ok(Box::new(evdev::EVDEVSource::new(options)))
 }
 
-pub use layout::get_active_layout;
\ No newline at end of file
+pub use layout::get_active_layout;
diff --git a/espanso-detect/src/win32/mod.rs b/espanso-detect/src/win32/mod.rs
index 4c60f9d..7e5537e 100644
--- a/espanso-detect/src/win32/mod.rs
+++ b/espanso-detect/src/win32/mod.rs
@@ -64,6 +64,12 @@ pub struct RawInputEvent {
   pub key_code: i32,
   pub variant: i32,
   pub status: i32,
+
+  // Only relevant for keyboard events, this is set to 1
+  // if a keyboard event has an explicit source, 0 otherwise.
+  // This is needed to filter out software generated events,
+  // including those from espanso.
+  pub has_known_source: i32,
 }
 
 #[repr(C)]
@@ -91,15 +97,18 @@ pub struct Win32Source {
   handle: *mut c_void,
   callback: LazyCell<SourceCallback>,
   hotkeys: Vec<HotKey>,
+
+  exclude_orphan_events: bool,
 }
 
 #[allow(clippy::new_without_default)]
 impl Win32Source {
-  pub fn new(hotkeys: &[HotKey]) -> Win32Source {
+  pub fn new(hotkeys: &[HotKey], exclude_orphan_events: bool) -> Win32Source {
     Self {
       handle: std::ptr::null_mut(),
       callback: LazyCell::new(),
       hotkeys: hotkeys.to_vec(),
+      exclude_orphan_events,
     }
   }
 }
@@ -148,6 +157,16 @@ impl Source for Win32Source {
     }
 
     extern "C" fn callback(_self: *mut Win32Source, event: RawInputEvent) {
+      // Filter out keyboard events without an explicit HID device source.
+      // This is needed to filter out the software-generated events, including 
+      // those from espanso.
+      if event.event_type == INPUT_EVENT_TYPE_KEYBOARD && event.has_known_source == 0 {
+        if unsafe { (*_self).exclude_orphan_events } {
+          trace!("skipping keyboard event with unknown HID source (probably software generated).");
+          return;
+        }
+      }
+
       let event: Option<InputEvent> = event.into();
       if let Some(callback) = unsafe { (*_self).callback.borrow() } {
         if let Some(event) = event {
@@ -391,6 +410,7 @@ mod tests {
       key_code: 0,
       variant: INPUT_LEFT_VARIANT,
       status: INPUT_STATUS_PRESSED,
+      has_known_source: 1,
     }
   }
 
@@ -459,6 +479,7 @@ mod tests {
       key_code: 123,
       variant: INPUT_LEFT_VARIANT,
       status: INPUT_STATUS_PRESSED,
+      has_known_source: 1,
     }
     .into();
     assert!(result.is_none());
diff --git a/espanso-detect/src/win32/native.cpp b/espanso-detect/src/win32/native.cpp
index 04a5ad6..673ccdb 100644
--- a/espanso-detect/src/win32/native.cpp
+++ b/espanso-detect/src/win32/native.cpp
@@ -121,6 +121,8 @@ LRESULT CALLBACK detect_window_procedure(HWND window, unsigned int msg, WPARAM w
         return 0;
       }
 
+      event.has_known_source = (raw->header.hDevice == 0) ? 0 : 1;
+
       // The alt key sends a SYSKEYDOWN instead of KEYDOWN event
       int is_key_down = raw->data.keyboard.Message == WM_KEYDOWN ||
                         raw->data.keyboard.Message == WM_SYSKEYDOWN;
diff --git a/espanso-detect/src/win32/native.h b/espanso-detect/src/win32/native.h
index c6e7dee..a93b9f7 100644
--- a/espanso-detect/src/win32/native.h
+++ b/espanso-detect/src/win32/native.h
@@ -60,6 +60,12 @@ typedef struct {
 
   // Pressed or Released status
   int32_t status;
+
+  // Only relevant for keyboard events, this is set to 1
+  // if a keyboard event has an explicit source, 0 otherwise.
+  // This is needed to filter out software generated events,
+  // including those from espanso.
+  int32_t has_known_source;
 } InputEvent;
 
 typedef struct {