From f35ae1ce7b312fe711476bdaaebb63ed2053eb08 Mon Sep 17 00:00:00 2001
From: Moonchild <moonchild@palemoon.org>
Date: Thu, 24 Nov 2022 21:41:28 +0000
Subject: [PATCH] Issue #2019 - Follow-up: Make nsPluginInstanceOwner also
 listen to keypress events in the system event group.

nsPluginInstanceOwner only listens to keypress events in the default event group.
However, in our changed operating mode, keypress events are not fired in the
default event group if the key does not result in something printable.
This means that nsPluginInstanceOwner should also listen to keypress events
in the system event group and should handle each keypress that way, but
only once. I.e., if a printable keypress event is received in the system event
group, it should be ignored, since it would've already been handled in the
default event group in that case.
---
 dom/plugins/base/nsPluginInstanceOwner.cpp | 44 +++++++++++++---------
 1 file changed, 26 insertions(+), 18 deletions(-)

diff --git a/dom/plugins/base/nsPluginInstanceOwner.cpp b/dom/plugins/base/nsPluginInstanceOwner.cpp
index 0d4dc68ccc..a8007f2c13 100644
--- a/dom/plugins/base/nsPluginInstanceOwner.cpp
+++ b/dom/plugins/base/nsPluginInstanceOwner.cpp
@@ -1480,6 +1480,16 @@ nsresult nsPluginInstanceOwner::DispatchFocusToPlugin(nsIDOMEvent* aFocusEvent)
 
 nsresult nsPluginInstanceOwner::ProcessKeyPress(nsIDOMEvent* aKeyEvent)
 {
+  // ProcessKeyPress() may be called twice with same eKeyPress event because we
+  // listen in both the default and system event groups (to capture keypresses
+  // potentially captured by plugins that are not printable keys).
+  // When this is called in the latter case and the event must be fired in the
+  // default event group too, we don't need to do anything else and can return.
+  if (!aKeyEvent->WidgetEventPtr()->mFlags.mOnlySystemGroupDispatchInContent &&
+      aKeyEvent->WidgetEventPtr()->mFlags.mInSystemGroup) {
+    return NS_OK;
+  }
+
 #ifdef XP_MACOSX
   return DispatchKeyToPlugin(aKeyEvent);
 #else
@@ -2547,6 +2557,7 @@ nsPluginInstanceOwner::Destroy()
   content->RemoveEventListener(NS_LITERAL_STRING("mouseover"), this, false);
   content->RemoveEventListener(NS_LITERAL_STRING("mouseout"), this, false);
   content->RemoveEventListener(NS_LITERAL_STRING("keypress"), this, true);
+  content->RemoveSystemEventListener(NS_LITERAL_STRING("keypress"), this, true);
   content->RemoveEventListener(NS_LITERAL_STRING("keydown"), this, true);
   content->RemoveEventListener(NS_LITERAL_STRING("keyup"), this, true);
   content->RemoveEventListener(NS_LITERAL_STRING("drop"), this, true);
@@ -2856,25 +2867,22 @@ nsresult nsPluginInstanceOwner::Init(nsIContent* aContent)
   // register context menu listener
   mCXMenuListener = new nsPluginDOMContextMenuListener(aContent);
 
-  aContent->AddEventListener(NS_LITERAL_STRING("focus"), this, false,
-                             false);
-  aContent->AddEventListener(NS_LITERAL_STRING("blur"), this, false,
-                             false);
-  aContent->AddEventListener(NS_LITERAL_STRING("mouseup"), this, false,
-                             false);
-  aContent->AddEventListener(NS_LITERAL_STRING("mousedown"), this, false,
-                             false);
-  aContent->AddEventListener(NS_LITERAL_STRING("mousemove"), this, false,
-                             false);
-  aContent->AddEventListener(NS_LITERAL_STRING("click"), this, false,
-                             false);
-  aContent->AddEventListener(NS_LITERAL_STRING("dblclick"), this, false,
-                             false);
-  aContent->AddEventListener(NS_LITERAL_STRING("mouseover"), this, false,
-                             false);
-  aContent->AddEventListener(NS_LITERAL_STRING("mouseout"), this, false,
-                             false);
+  aContent->AddEventListener(NS_LITERAL_STRING("focus"), this, false, false);
+  aContent->AddEventListener(NS_LITERAL_STRING("blur"), this, false, false);
+  aContent->AddEventListener(NS_LITERAL_STRING("mouseup"), this, false, false);
+  aContent->AddEventListener(NS_LITERAL_STRING("mousedown"), this, false, false);
+  aContent->AddEventListener(NS_LITERAL_STRING("mousemove"), this, false, false);
+  aContent->AddEventListener(NS_LITERAL_STRING("click"), this, false, false);
+  aContent->AddEventListener(NS_LITERAL_STRING("dblclick"), this, false, false);
+  aContent->AddEventListener(NS_LITERAL_STRING("mouseover"), this, false, false);
+  aContent->AddEventListener(NS_LITERAL_STRING("mouseout"), this, false, false);
+
+  // The "keypress" event should be handled when it's in the default event group
+  // if the event is fired in content.
+  // Otherwise, it should be handled when it's in the system event group.
   aContent->AddEventListener(NS_LITERAL_STRING("keypress"), this, true);
+  aContent->AddSystemEventListener(NS_LITERAL_STRING("keypress"), this, true);
+  
   aContent->AddEventListener(NS_LITERAL_STRING("keydown"), this, true);
   aContent->AddEventListener(NS_LITERAL_STRING("keyup"), this, true);
   aContent->AddEventListener(NS_LITERAL_STRING("drop"), this, true);