When receiving a key event on Windows, set host lock state to match client's

remoting/host/input_injector_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "remoting/host/input_injector.h"
 
 #include <stdint.h>
 #include <windows.h>
 
 #include <utility>
@@ skipping 181 matching lines @@
 
    private:
     friend class base::RefCountedThreadSafe<Core>;
     virtual ~Core();
 
     void HandleKey(const KeyEvent& event);
     void HandleText(const TextEvent& event);
     void HandleMouse(const MouseEvent& event);
     void HandleTouch(const TouchEvent& event);
 
+    // Check if the given scan code is caps lock or num lock.
+    bool IsLockKey(int scancode);
+
+    // Sets the keyboard lock states to those provided.
+    void SetLockStates(uint32_t states);
+
     scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
     scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
     std::unique_ptr<Clipboard> clipboard_;
     std::unique_ptr<TouchInjectorWin> touch_injector_;
 
     DISALLOW_COPY_AND_ASSIGN(Core);
   };
 
   scoped_refptr<Core> core_;
 
@@ skipping 129 matching lines @@
 
   int scancode =
       ui::KeycodeConverter::UsbKeycodeToNativeKeycode(event.usb_keycode());
   VLOG(3) << "Converting USB keycode: " << std::hex << event.usb_keycode()
           << " to scancode: " << scancode << std::dec;
 
   // Ignore events which can't be mapped.
   if (scancode == ui::KeycodeConverter::InvalidNativeKeycode())
     return;
 
+  if (event.has_lock_states() && !IsLockKey(scancode)) {
+    SetLockStates(event.lock_states());
+  }
+
   uint32_t flags = KEYEVENTF_SCANCODE | (event.pressed() ? 0 : KEYEVENTF_KEYUP);
   SendKeyboardInput(flags, scancode);
 }
 
 void InputInjectorWin::Core::HandleText(const TextEvent& event) {
   // HostEventDispatcher should filter events missing the pressed field.
   DCHECK(event.has_text());
 
   base::string16 text = base::UTF8ToUTF16(event.text());
   for (base::string16::const_iterator it = text.begin();
@@ skipping 16 matching lines @@
     if (SendInput(inputs.size(), inputs.data(), sizeof(INPUT)) != inputs.size())
       PLOG(ERROR) << "Failed to inject a mouse event";
   }
 }
 
 void InputInjectorWin::Core::HandleTouch(const TouchEvent& event) {
   DCHECK(touch_injector_);
   touch_injector_->InjectTouchEvent(event);
 }
 
+bool InputInjectorWin::Core::IsLockKey(int scancode) {
+  UINT virtual_key = MapVirtualKey(scancode, MAPVK_VSC_TO_VK);
+  return virtual_key == VK_CAPITAL || virtual_key == VK_NUMLOCK;
+}
+
+void InputInjectorWin::Core::SetLockStates(uint32_t states) {
+  // Can't use SendKeyboardInput because we need to send virtual key codes, not
+  // scan codes.
+  INPUT input[2] = {};
+  input[0].type = INPUT_KEYBOARD;
+  input[1].type = INPUT_KEYBOARD;
+  input[1].ki.dwFlags = KEYEVENTF_KEYUP;
+
+  bool client_capslock_state =
+      states & protocol::KeyEvent::LOCK_STATES_CAPSLOCK;

[joedow, 2017/05/01 15:14:28]

I get a build error, this works though:
bool client_capslock_state =
      (states & protocol::KeyEvent::LOCK_STATES_CAPSLOCK) != 0;

One note is that using the try-bots would have helped catch this sooner.

[rkjnsn, 2017/05/01 17:46:27]

I ran the code through Clang before uploading, but it looks like this is a
VC++-only "performance warning". (As an aside, I think the warning itself is a
little dubious, as the performance implication of boolification is negligible in
almost all cases. It'd make more sense if it were a style warning, but it's not,
as evidenced by the fact that the warning doesn't trigger on the next line.)

Anyway, fixed. I changed the following line, too, to be consistent.

+  bool host_capslock_state = GetKeyState(VK_CAPITAL) & 1;
+  if (client_capslock_state != host_capslock_state) {
+    input[0].ki.wVk = VK_CAPITAL;
+    input[1].ki.wVk = VK_CAPITAL;
+    SendInput(arraysize(input), input, sizeof(INPUT));
+  }
+
+  bool client_numlock_state = states & protocol::KeyEvent::LOCK_STATES_NUMLOCK;

[joedow, 2017/05/01 15:14:28]

Another build error:
  bool client_numlock_state =
      (states & protocol::KeyEvent::LOCK_STATES_NUMLOCK) != 0;

[rkjnsn, 2017/05/01 17:46:27]

Changed along with following line.

+  bool host_numlock_state = GetKeyState(VK_NUMLOCK) & 1;
+  if (client_numlock_state != host_numlock_state) {
+    input[0].ki.wVk = VK_NUMLOCK;
+    input[1].ki.wVk = VK_NUMLOCK;
+    SendInput(arraysize(input), input, sizeof(INPUT));
+  }
+}
+
 }  // namespace
 
 // static
 std::unique_ptr<InputInjector> InputInjector::Create(
     scoped_refptr<base::SingleThreadTaskRunner> main_task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner) {
   return base::WrapUnique(
       new InputInjectorWin(main_task_runner, ui_task_runner));
 }
 
 // static
 bool InputInjector::SupportsTouchEvents() {
   return base::win::GetVersion() >= base::win::VERSION_WIN8;
 }
 
 }  // namespace remoting