From 4f8ba2beb9fb818d9e072942b7d089c18eba3d3b Mon Sep 17 00:00:00 2001
From: rogerman <rogerman@users.noreply.github.com>
Date: Mon, 30 Aug 2021 20:02:49 -0700
Subject: [PATCH] task.cpp: Support thread naming on macOS. - Related to commit
 11fe823 and commit e70e065.

---
 .../src/libretro-common/rthreads/rthreads.c   |  8 +++-
 desmume/src/utils/task.cpp                    | 45 ++++++++++++++++++-
 2 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/desmume/src/libretro-common/rthreads/rthreads.c b/desmume/src/libretro-common/rthreads/rthreads.c
index 45d84f5df..e2238823b 100644
--- a/desmume/src/libretro-common/rthreads/rthreads.c
+++ b/desmume/src/libretro-common/rthreads/rthreads.c
@@ -314,7 +314,13 @@ void sthread_setname(sthread_t *thread, const char *name)
 {
    if (!thread)
       return;
-   // TODO: implement that for Windows (and Mac?) too.
+   // TODO: implement that for Windows too.
+   // This can't be implemented on Apple OSes because pthread_setname_np() works
+   // substantially different. Not only does pthread_setname_np() take only the
+   // 'name' parameter, but it can only change the thread name on the current
+   // thread, when standard pthread_setname_np() can set the thread name from
+   // any thread. At the time of this writing (2021/08/30), there is no way to
+   // set the thread name from a different thread when running an Apple OS.
 #if !defined(USE_WIN32_THREADS) && !defined(__APPLE__)
    pthread_setname_np(thread->id, name);
 #endif
diff --git a/desmume/src/utils/task.cpp b/desmume/src/utils/task.cpp
index 8f785e2ae..d1e898cd2 100644
--- a/desmume/src/utils/task.cpp
+++ b/desmume/src/utils/task.cpp
@@ -16,11 +16,18 @@
 */
 
 #include <stdio.h>
+#include <string.h>
 
 #include "types.h"
 #include "task.h"
 #include <rthreads/rthreads.h>
 
+#ifdef __APPLE__
+#include <AvailabilityMacros.h>
+#include <CoreFoundation/CoreFoundation.h>
+#include <pthread.h>
+#endif
+
 class Task::Impl {
 private:
 	sthread_t* _thread;
@@ -35,6 +42,9 @@ public:
 	void* finish();
 	void shutdown();
 
+	bool needSetThreadName;
+	char threadName[16]; // pthread_setname_np() assumes a max character length of 16.
+	
 	slock_t *mutex;
 	scond_t *condWork;
 	TWork workFunc;
@@ -46,6 +56,19 @@ public:
 static void taskProc(void *arg)
 {
 	Task::Impl *ctx = (Task::Impl *)arg;
+	
+	// The pthread_setname_np() function is gimped on macOS because it can't set thread
+	// names from any thread other than the current thread. That's why we can only set the
+	// thread name right here. We are not modifying rthreads, which is meant to be
+	// cross-platform, due to the substantially different nature of macOS's gimped version
+	// of pthread_setname_np().
+#if defined(MAC_OS_X_VERSION_10_6) && (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6)
+	if (ctx->needSetThreadName)
+	{
+		pthread_setname_np(ctx->threadName);
+		ctx->needSetThreadName = false;
+	}
+#endif
 
 	do {
 		slock_lock(ctx->mutex);
@@ -75,6 +98,9 @@ Task::Impl::Impl()
 	workFuncParam = NULL;
 	ret = NULL;
 	exitThread = false;
+	
+	memset(threadName, 0, sizeof(threadName));
+	needSetThreadName = false;
 
 	mutex = slock_new();
 	condWork = scond_new();
@@ -102,8 +128,23 @@ void Task::Impl::start(bool spinlock, int threadPriority, const char *name)
 	this->exitThread = false;
 	this->_thread = sthread_create_with_priority(&taskProc, this, threadPriority);
 	this->_isThreadRunning = true;
-	if (name)
-		sthread_setname(this->_thread, name);
+	
+#if !defined(USE_WIN32_THREADS) && !defined(__APPLE__)
+	sthread_setname(this->_thread, name);
+#else
+	
+#if defined(MAC_OS_X_VERSION_10_6) && (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6)
+	// Setting the thread name on macOS uses pthread_setname_np(), but this requires macOS v10.6 or later.
+	this->needSetThreadName = (kCFCoreFoundationVersionNumber >= kCFCoreFoundationVersionNumber10_6) && (name != NULL);
+#else
+	this->needSetThreadName = (name != NULL);
+#endif
+	
+	if (this->needSetThreadName)
+	{
+		strncpy(this->threadName, name, sizeof(this->threadName));
+	}
+#endif
 	
 	slock_unlock(this->mutex);
 }