From 042a2d72f722720fcb96b1aba46ee49e62403c6f Mon Sep 17 00:00:00 2001
From: Stenzek <stenzek@gmail.com>
Date: Thu, 5 Dec 2024 19:57:18 +1000
Subject: [PATCH] Threading: Add IsCallingThread() to ThreadHandle

---
 src/common/threading.cpp | 25 ++++++++++++++++++++++---
 src/common/threading.h   |  9 ++++++++-
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/src/common/threading.cpp b/src/common/threading.cpp
index 2012fcb22..025e1b991 100644
--- a/src/common/threading.cpp
+++ b/src/common/threading.cpp
@@ -7,6 +7,7 @@
 #include "log.h"
 
 #include <memory>
+#include <utility>
 
 #if !defined(_WIN32) && !defined(__APPLE__)
 #ifndef _GNU_SOURCE
@@ -164,8 +165,9 @@ Threading::ThreadHandle Threading::ThreadHandle::GetForCallingThread()
 {
   ThreadHandle ret;
 #ifdef _WIN32
+  ret.m_native_id = GetCurrentThreadId();
   ret.m_native_handle =
-    (void*)OpenThread(THREAD_QUERY_INFORMATION | THREAD_SET_LIMITED_INFORMATION, FALSE, GetCurrentThreadId());
+    (void*)OpenThread(THREAD_QUERY_INFORMATION | THREAD_SET_LIMITED_INFORMATION, FALSE, ret.m_native_id);
 #else
   ret.m_native_handle = (void*)pthread_self();
 #ifdef __linux__
@@ -181,7 +183,9 @@ Threading::ThreadHandle& Threading::ThreadHandle::operator=(ThreadHandle&& handl
   if (m_native_handle)
     CloseHandle((HANDLE)m_native_handle);
   m_native_handle = handle.m_native_handle;
+  m_native_id = handle.m_native_id;
   handle.m_native_handle = nullptr;
+  handle.m_native_id = 0;
 #else
   m_native_handle = handle.m_native_handle;
   handle.m_native_handle = nullptr;
@@ -207,6 +211,12 @@ Threading::ThreadHandle& Threading::ThreadHandle::operator=(const ThreadHandle&
                       THREAD_QUERY_INFORMATION | THREAD_SET_LIMITED_INFORMATION, FALSE, 0))
   {
     m_native_handle = (void*)new_handle;
+    m_native_id = handle.m_native_id;
+  }
+  else
+  {
+    m_native_handle = nullptr;
+    m_native_id = 0;
   }
 #else
   m_native_handle = handle.m_native_handle;
@@ -275,6 +285,15 @@ bool Threading::ThreadHandle::SetAffinity(u64 processor_mask) const
 #endif
 }
 
+bool Threading::ThreadHandle::IsCallingThread() const
+{
+#ifdef _WIN32
+  return (GetCurrentThreadId() == m_native_id);
+#else
+  return pthread_equal(pthread_self(), (pthread_t)m_native_handle);
+#endif
+}
+
 #ifdef __APPLE__
 
 bool Threading::ThreadHandle::SetTimeConstraints(bool enabled, u64 period, u64 typical_time, u64 maximum_time)
@@ -317,9 +336,9 @@ bool Threading::ThreadHandle::SetTimeConstraints(bool enabled, u64 period, u64 t
 
 Threading::Thread::Thread() = default;
 
-Threading::Thread::Thread(Thread&& thread) : ThreadHandle(thread), m_stack_size(thread.m_stack_size)
+Threading::Thread::Thread(Thread&& thread) : ThreadHandle(thread)
 {
-  thread.m_stack_size = 0;
+  m_stack_size = std::exchange(thread.m_stack_size, 0);
 }
 
 Threading::Thread::Thread(EntryPoint func) : ThreadHandle()
diff --git a/src/common/threading.h b/src/common/threading.h
index 4b8934f40..82bd52e61 100644
--- a/src/common/threading.h
+++ b/src/common/threading.h
@@ -53,6 +53,9 @@ public:
   /// Obviously, only works up to 64 processors.
   bool SetAffinity(u64 processor_mask) const;
 
+  /// Returns true if the calling thread matches this handle.
+  bool IsCallingThread() const;
+
 #ifdef __APPLE__
   /// Only available on MacOS, sets a period/maximum time for the scheduler.
   bool SetTimeConstraints(bool enabled, u64 period, u64 typical_time, u64 maximum_time);
@@ -62,8 +65,9 @@ protected:
   void* m_native_handle = nullptr;
 
   // We need the thread ID for affinity adjustments on Linux.
-#if defined(__linux__)
+#if defined(_WIN32) || defined(__linux__)
   unsigned int m_native_id = 0;
+  u32 m_stack_size = 0;
 #endif
 };
 
@@ -104,7 +108,10 @@ protected:
   static void* ThreadProc(void* param);
 #endif
 
+#if !defined(_WIN32) && !defined(__linux__)
+  // Stored in ThreadHandle to save 8 bytes.
   u32 m_stack_size = 0;
+#endif
 };
 
 /// A semaphore that requires a system call to wake/sleep.