Allow sync HTTP fetches to be interrupted to fix hanging (#14412)

Co-authored-by: Jude Melton-Houghton <jwmhjwmh@gmail.com>

src/threading/thread.cpp

@@ -62,6 +62,9 @@ DEALINGS IN THE SOFTWARE.
 // See https://msdn.microsoft.com/en-us/library/hh920601.aspx#thread__native_handle_method
 #define win32_native_handle() ((HANDLE) getThreadHandle())
 
+thread_local Thread *current_thread = nullptr;
+
+
 Thread::Thread(const std::string &name) :
 	m_name(name),
 	m_request_stop(false),
@@ -177,6 +180,8 @@ void Thread::threadProc(Thread *thr)
 	thr->m_kernel_thread_id = thread_self();
 #endif
 
+	current_thread = thr;
+
 	thr->setName(thr->m_name);
 
 	g_logger.registerThread(thr->m_name);
@@ -197,6 +202,12 @@ void Thread::threadProc(Thread *thr)
 }
 
 
+Thread *Thread::getCurrentThread()
+{
+	return current_thread;
+}
+
+
 void Thread::setName(const std::string &name)
 {
 #if defined(__linux__)

src/threading/thread.h

@@ -119,6 +119,11 @@ public:
 	 */
 	bool setPriority(int prio);
 
+	/*
+	 * Returns the thread object of the current thread if it exists.
+	 */
+	static Thread *getCurrentThread();
+
 	/*
 	 * Sets the currently executing thread's name to where supported; useful
 	 * for debugging.