From 7a8d18a7617a00f67df22f54e0d388dbacdbe238 Mon Sep 17 00:00:00 2001
From: Peter Donovan <peter@xronos.com>
Date: Thu, 27 Jun 2024 12:28:50 -0700
Subject: [PATCH] Support getting current thread on Windows

Also, silence undefined reference linker errors on other platforms that
either have no support or that do not currently implement the API
---
 low_level_platform/impl/src/lf_arduino_support.c  | 10 ++++++++++
 low_level_platform/impl/src/lf_flexpret_support.c |  7 +++++++
 low_level_platform/impl/src/lf_windows_support.c  |  2 ++
 3 files changed, 19 insertions(+)

diff --git a/low_level_platform/impl/src/lf_arduino_support.c b/low_level_platform/impl/src/lf_arduino_support.c
index ed9391205..c56d288dc 100644
--- a/low_level_platform/impl/src/lf_arduino_support.c
+++ b/low_level_platform/impl/src/lf_arduino_support.c
@@ -170,6 +170,16 @@ typedef void* (*lf_function_t)(void*);
  */
 int lf_available_cores() { return 1; }
 
+lf_thread_t lf_thread_self() {
+  // Not implemented. Although Arduino mbed provides a ThisThread API and a
+  // get_id() function, it does not provide a way to get the current thread as a
+  // Thread object.
+  // N.B. This wrong implementation will eventually cause hard-to-debug
+  // segfaults, but it unblocks us from conveniently implementing features for
+  // other platforms, and it does not break existing features for Arduino.
+  return NULL;
+}
+
 int lf_thread_create(lf_thread_t* thread, void* (*lf_thread)(void*), void* arguments) {
   lf_thread_t t = thread_new();
   long int start = thread_start(t, *lf_thread, arguments);
diff --git a/low_level_platform/impl/src/lf_flexpret_support.c b/low_level_platform/impl/src/lf_flexpret_support.c
index 9d83283c5..7962f9d3b 100644
--- a/low_level_platform/impl/src/lf_flexpret_support.c
+++ b/low_level_platform/impl/src/lf_flexpret_support.c
@@ -178,6 +178,13 @@ int lf_available_cores() {
   return FP_THREADS - 1; // Return the number of Flexpret HW threads
 }
 
+lf_thread_t lf_thread_self() {
+  // N.B. This wrong implementation will eventually cause hard-to-debug
+  // segfaults, but it unblocks us from conveniently implementing features for
+  // other platforms, and it does not break existing features for FlexPRET.
+  return NULL;
+}
+
 int lf_thread_create(lf_thread_t* thread, void* (*lf_thread)(void*), void* arguments) {
   /**
    * Need to select between HRTT or SRTT; see
diff --git a/low_level_platform/impl/src/lf_windows_support.c b/low_level_platform/impl/src/lf_windows_support.c
index 1d48bc6c7..61424ac7f 100644
--- a/low_level_platform/impl/src/lf_windows_support.c
+++ b/low_level_platform/impl/src/lf_windows_support.c
@@ -162,6 +162,8 @@ int lf_available_cores() {
   return sysinfo.dwNumberOfProcessors;
 }
 
+lf_thread_t lf_thread_self() { return GetCurrentThread(); }
+
 int lf_thread_create(lf_thread_t* thread, void* (*lf_thread)(void*), void* arguments) {
   uintptr_t handle = _beginthreadex(NULL, 0, lf_thread, arguments, 0, NULL);
   *thread = (HANDLE)handle;