https://bugs.gentoo.org/863008
https://bugs.webkit.org/show_bug.cgi?id=243401

From a6277d4834cce0dea2f999d4c06ffa57abfbb82d Mon Sep 17 00:00:00 2001
From: Michael Catanzaro <mcatanzaro@redhat.com>
Date: Mon, 1 Aug 2022 14:07:04 -0700
Subject: [PATCH] REGRESSION(252485@main): [GTK]
 webkit_web_context_get_default() crashes in Eclipse since webkit-gtk v2.36.5,
 v2.36.4 was fine https://bugs.webkit.org/show_bug.cgi?id=243401

Reviewed by Adrian Perez de Castro.

Turns out WebKit's "main thread" may not actually be the real main
thread. This is OK as long as it matches the GTK "main thread," and as
long as the application is careful to iterate the default main context
only on the WebKit/GTK "main thread," as as long as the application does
not ever attempt to use these libraries on any other thread.

The motivation to do this is if the programming language controls the
real thread 1, as is the case with Java, where the Java main thread that
applications can use to run GTK and WebKit is apparently not the same as
the real main thread that's running the JVM. These applications have no
control over what their "main thread" is, and it seems unkind to break
them.

I've checked in with the GTK developers, and consensus is that this
is actually expected to work, so let's not break it.

* Source/WTF/wtf/generic/MainThreadGeneric.cpp:
(WTF::initializeMainThreadPlatform):
(WTF::isMainThread):

Canonical link: https://commits.webkit.org/253010@main
---
 Source/WTF/wtf/generic/MainThreadGeneric.cpp | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/Source/WTF/wtf/generic/MainThreadGeneric.cpp b/Source/WTF/wtf/generic/MainThreadGeneric.cpp
index 3a9208b0f9ab..b51e2e456047 100644
--- a/Source/WTF/wtf/generic/MainThreadGeneric.cpp
+++ b/Source/WTF/wtf/generic/MainThreadGeneric.cpp
@@ -31,29 +31,22 @@
  */
 
 #include "config.h"
-#if !OS(LINUX)
 #include <pthread.h>
-#endif
 #if HAVE(PTHREAD_NP_H)
 #include <pthread_np.h>
 #endif
-#if OS(LINUX)
-#include <sys/syscall.h>
-#include <sys/types.h>
-#include <unistd.h>
-#endif
 
 #include <wtf/RunLoop.h>
 
 namespace WTF {
 
-#if !HAVE(PTHREAD_MAIN_NP) && !OS(LINUX)
+#if !HAVE(PTHREAD_MAIN_NP)
 static pthread_t mainThread;
 #endif
 
 void initializeMainThreadPlatform()
 {
-#if !HAVE(PTHREAD_MAIN_NP) && !OS(LINUX)
+#if !HAVE(PTHREAD_MAIN_NP)
     mainThread = pthread_self();
 #endif
 }
@@ -62,8 +55,6 @@ bool isMainThread()
 {
 #if HAVE(PTHREAD_MAIN_NP)
     return pthread_main_np();
-#elif OS(LINUX)
-    return getpid() == static_cast<pid_t>(syscall(SYS_gettid));
 #else
     return pthread_equal(pthread_self(), mainThread);
 #endif