From 32e0f7f6213648449f3a74da1ea897d3f10e74a9 Mon Sep 17 00:00:00 2001
From: ownedbywuigi <ownedbywuigi@gmail.com>
Date: Mon, 30 Mar 2026 00:30:51 +0100
Subject: [PATCH] Add infallibleInit method to ThreadLocal and AssertOwns
 methods to Mutex

---
 mfbt/ThreadLocal.h | 11 +++++++++++
 xpcom/glue/Mutex.h | 15 +++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/mfbt/ThreadLocal.h b/mfbt/ThreadLocal.h
index f1f8264e8e..7da87f248c 100644
--- a/mfbt/ThreadLocal.h
+++ b/mfbt/ThreadLocal.h
@@ -132,6 +132,8 @@ public:
 
   MOZ_MUST_USE inline bool init();
 
+  inline void infallibleInit();
+
   inline T get() const;
 
   inline void set(const T aValue);
@@ -171,6 +173,15 @@ ThreadLocal<T>::init()
 #endif
 }
 
+template<typename T>
+inline void
+ThreadLocal<T>::infallibleInit()
+{
+  if (!init()) {
+    MOZ_CRASH("unable to initialize ThreadLocal");
+  }
+}
+
 template<typename T>
 inline T
 ThreadLocal<T>::get() const
diff --git a/xpcom/glue/Mutex.h b/xpcom/glue/Mutex.h
index 895721f06c..f4556f3315 100644
--- a/xpcom/glue/Mutex.h
+++ b/xpcom/glue/Mutex.h
@@ -172,6 +172,21 @@ public:
     mLock->Unlock();
   }
 
+  // Assert that the current thread owns the lock right now.
+  void AssertOwns() const
+  {
+    mLock->AssertCurrentThreadOwns();
+  }
+
+  // Assert that aLock is the lock passed to the constructor and that the
+  // current thread owns it. Pointer equality alone is not sufficient because
+  // lock ownership may be temporarily released with BaseAutoUnlock.
+  void AssertOwns(const T& aLock) const
+  {
+    MOZ_ASSERT(&aLock == mLock);
+    AssertOwns();
+  }
+
 private:
   BaseAutoLock();
   BaseAutoLock(BaseAutoLock&);