From 30d83cb94a79e6548ecb4db4f8d6ad587f3b3177 Mon Sep 17 00:00:00 2001
From: Mike Wiedenbauer <mike.wiedenbauer@unblu.com>
Date: Wed, 8 Apr 2020 15:43:39 +0000
Subject: [PATCH] Fix AltGr handling for OSR keyboard events (fixes issue
 #2892)

---
 include/internal/cef_types.h                  |  1 +
 .../browser_platform_delegate_native_aura.cc  |  2 ++
 .../browser_platform_delegate_native_linux.cc | 10 ++++++++++
 .../browser_platform_delegate_native_linux.h  |  2 ++
 tests/cefclient/browser/osr_window_win.cc     | 19 +++++++++++++++++++
 5 files changed, 34 insertions(+)

diff --git a/include/internal/cef_types.h b/include/internal/cef_types.h
index c76722316..dded757bc 100644
--- a/include/internal/cef_types.h
+++ b/include/internal/cef_types.h
@@ -1780,6 +1780,7 @@ typedef enum {
   EVENTFLAG_IS_KEY_PAD = 1 << 9,
   EVENTFLAG_IS_LEFT = 1 << 10,
   EVENTFLAG_IS_RIGHT = 1 << 11,
+  EVENTFLAG_ALTGR_DOWN = 1 << 12,
 } cef_event_flags_t;
 
 ///
diff --git a/libcef/browser/native/browser_platform_delegate_native_aura.cc b/libcef/browser/native/browser_platform_delegate_native_aura.cc
index e036c98ea..db5ceb1ea 100644
--- a/libcef/browser/native/browser_platform_delegate_native_aura.cc
+++ b/libcef/browser/native/browser_platform_delegate_native_aura.cc
@@ -210,6 +210,8 @@ int CefBrowserPlatformDelegateNativeAura::TranslateUiEventModifiers(
     result |= ui::EF_CAPS_LOCK_ON;
   if (cef_modifiers & EVENTFLAG_NUM_LOCK_ON)
     result |= ui::EF_NUM_LOCK_ON;
+  if (cef_modifiers & EVENTFLAG_ALTGR_DOWN)
+    result |= ui::EF_ALTGR_DOWN;
   return result;
 }
 
diff --git a/libcef/browser/native/browser_platform_delegate_native_linux.cc b/libcef/browser/native/browser_platform_delegate_native_linux.cc
index cd8ef7e61..b6364b2f0 100644
--- a/libcef/browser/native/browser_platform_delegate_native_linux.cc
+++ b/libcef/browser/native/browser_platform_delegate_native_linux.cc
@@ -313,6 +313,16 @@ ui::KeyEvent CefBrowserPlatformDelegateNativeLinux::TranslateUiKeyEvent(
   return ui::KeyEvent(type, key_code, dom_code, flags, dom_key, time_stamp);
 }
 
+content::NativeWebKeyboardEvent
+CefBrowserPlatformDelegateNativeLinux::TranslateWebKeyEvent(
+    const CefKeyEvent& key_event) const {
+  ui::KeyEvent ui_event = TranslateUiKeyEvent(key_event);
+  if (key_event.type == KEYEVENT_CHAR) {
+    return content::NativeWebKeyboardEvent(ui_event, key_event.character);
+  }
+  return content::NativeWebKeyboardEvent(ui_event);
+}
+
 base::TimeTicks CefBrowserPlatformDelegateNativeLinux::GetEventTimeStamp()
     const {
   return base::TimeTicks() + base::TimeDelta::FromSeconds(GetSystemUptime());
diff --git a/libcef/browser/native/browser_platform_delegate_native_linux.h b/libcef/browser/native/browser_platform_delegate_native_linux.h
index 96ee95a76..7f1834a3d 100644
--- a/libcef/browser/native/browser_platform_delegate_native_linux.h
+++ b/libcef/browser/native/browser_platform_delegate_native_linux.h
@@ -40,6 +40,8 @@ class CefBrowserPlatformDelegateNativeLinux
 
   // CefBrowserPlatformDelegateNativeAura methods:
   ui::KeyEvent TranslateUiKeyEvent(const CefKeyEvent& key_event) const override;
+  content::NativeWebKeyboardEvent TranslateWebKeyEvent(
+      const CefKeyEvent& key_event) const override;
   base::TimeTicks GetEventTimeStamp() const override;
 
  private:
diff --git a/tests/cefclient/browser/osr_window_win.cc b/tests/cefclient/browser/osr_window_win.cc
index 1be90d78d..66b220d05 100644
--- a/tests/cefclient/browser/osr_window_win.cc
+++ b/tests/cefclient/browser/osr_window_win.cc
@@ -791,6 +791,25 @@ void OsrWindowWin::OnKeyEvent(UINT message, WPARAM wParam, LPARAM lParam) {
     event.type = KEYEVENT_CHAR;
   event.modifiers = GetCefKeyboardModifiers(wParam, lParam);
 
+  // mimic alt-gr check behaviour from
+  // src/ui/events/win/events_win_utils.cc: GetModifiersFromKeyState
+  if ((event.type == KEYEVENT_CHAR) && IsKeyDown(VK_RMENU)) {
+    // reverse AltGr detection taken from PlatformKeyMap::UsesAltGraph
+    // instead of checking all combination for ctrl-alt, just check current char
+    HKL current_layout = ::GetKeyboardLayout(0);
+
+    // https://docs.microsoft.com/en-gb/windows/win32/api/winuser/nf-winuser-vkkeyscanexw
+    // ... high-order byte contains the shift state,
+    // which can be a combination of the following flag bits.
+    // 2 Either CTRL key is pressed.
+    // 4 Either ALT key is pressed.
+    SHORT scan_res = ::VkKeyScanExW(wParam, current_layout);
+    if (((scan_res >> 8) & 0xFF) == (2 | 4)) {  // ctrl-alt pressed
+      event.modifiers &= ~(EVENTFLAG_CONTROL_DOWN | EVENTFLAG_ALT_DOWN);
+      event.modifiers |= EVENTFLAG_ALTGR_DOWN;
+    }
+  }
+
   browser_->GetHost()->SendKeyEvent(event);
 }