From ed6362abd2ceac83a2f15319ae381f2ab4fdaebd Mon Sep 17 00:00:00 2001
From: Ray Kraesig <rkraesig@mozilla.com>
Date: Thu, 16 Feb 2023 00:48:08 +0000
Subject: [PATCH] Bug 1814532 [1/4] - actually record WindowProc return values 
 r=gstoll

The value currently being logged as the WndProc LRESULT is actually
garbage. Log the actual LRESULT after calling ProcessMessageInternal(),
instead.

Differential Revision: https://phabricator.services.mozilla.com/D168874
---
 widget/windows/nsWindow.cpp    |  4 ++--
 widget/windows/nsWindowDbg.cpp |  4 +---
 widget/windows/nsWindowDbg.h   | 14 +++++++++-----
 3 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/widget/windows/nsWindow.cpp b/widget/windows/nsWindow.cpp
index 32244d654969..0abe408f888a 100644
--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -5100,9 +5100,9 @@ bool nsWindow::ProcessMessage(UINT msg, WPARAM& wParam, LPARAM& lParam,
                               LRESULT* aRetValue) {
   // For some events we might change the parameter values, so log
   // before and after we process them.
-  PrintEvent printEvent(mWnd, msg, wParam, lParam, *aRetValue);
+  PrintEvent printEvent(mWnd, msg, wParam, lParam);
   bool result = ProcessMessageInternal(msg, wParam, lParam, aRetValue);
-  printEvent.SetResult(result);
+  printEvent.SetResult(*aRetValue, result);
 
   return result;
 }
diff --git a/widget/windows/nsWindowDbg.cpp b/widget/windows/nsWindowDbg.cpp
index a6d63f3aefa6..7b27f56820f4 100644
--- a/widget/windows/nsWindowDbg.cpp
+++ b/widget/windows/nsWindowDbg.cpp
@@ -54,13 +54,11 @@ std::unordered_set<UINT> gEventsToRecordInAboutPage = {WM_WINDOWPOSCHANGING,
                                                        WM_MOVING,
                                                        WM_GETMINMAXINFO};
 
-PrintEvent::PrintEvent(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam,
-                       LRESULT retValue)
+PrintEvent::PrintEvent(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
     : mHwnd(hwnd),
       mMsg(msg),
       mWParam(wParam),
       mLParam(lParam),
-      mRetValue(retValue),
       mResult(mozilla::Nothing()),
       mShouldLogPostCall(false) {
   if (PrintEventInternal()) {
diff --git a/widget/windows/nsWindowDbg.h b/widget/windows/nsWindowDbg.h
index 672ec9756b60..9e2ed15384fd 100644
--- a/widget/windows/nsWindowDbg.h
+++ b/widget/windows/nsWindowDbg.h
@@ -43,21 +43,25 @@ extern std::unordered_map<UINT, EventMsgInfo> gAllEvents;
 // RAII-style class to log before and after an event is handled.
 class PrintEvent final {
  public:
-  PrintEvent(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam,
-             LRESULT retValue);
-  void SetResult(bool result) { mResult = mozilla::Some(result); }
+  PrintEvent(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
+  void SetResult(LRESULT lresult, bool result) {
+    mRetValue = lresult;
+    mResult = mozilla::Some(result);
+  }
   ~PrintEvent();
 
  private:
   bool PrintEventInternal();
+
   const HWND mHwnd;
   const UINT mMsg;
   const WPARAM mWParam;
   const LPARAM mLParam;
-  const LRESULT mRetValue;
   mozilla::Maybe<long> mEventCounter;
-  // not const because it will be set after the event is handled
+  // not const because these will be set after the event is handled
   mozilla::Maybe<bool> mResult;
+  LRESULT mRetValue = 0;
+
   bool mShouldLogPostCall;
 };