From b2a74fd651a0be8cb2866168c691e28eb8fc7ca0 Mon Sep 17 00:00:00 2001
From: Ezekiel Warren <zaucy@users.noreply.github.com>
Date: Thu, 12 Jan 2023 10:28:24 -0800
Subject: [PATCH] added cleanup/unload api (#27)

---
 ecsactsi_wasm.cc               | 40 +++++++++++++++++++++++++++++++++-
 ecsactsi_wasm.h                | 18 +++++++++++++++
 wasm_ecsact_system_execution.h |  2 +-
 3 files changed, 58 insertions(+), 2 deletions(-)

diff --git a/ecsactsi_wasm.cc b/ecsactsi_wasm.cc
index b97f6bf..9a6d4d5 100644
--- a/ecsactsi_wasm.cc
+++ b/ecsactsi_wasm.cc
@@ -279,6 +279,20 @@ wasm_engine_t* engine() {
 	return engine;
 }
 
+void unload_system_module(
+	ecsact_system_like_id                    sys_id,
+	ecsact_internal_wasm_system_module_info& info
+) {
+	ecsact_set_system_execution_impl(sys_id, nullptr);
+	wasm_module_delete(info.system_module);
+	wasm_instance_delete(info.instance);
+	wasm_func_delete(info.system_impl_func);
+	wasm_memory_delete(info.system_impl_memory);
+	wasm_store_delete(info.store);
+
+	info = {};
+}
+
 void ecsactsi_wasm_system_impl(ecsact_system_execution_context* ctx) {
 	auto lk = std::shared_lock(modules_mutex);
 	auto system_id = ecsact_system_execution_context_id(ctx);
@@ -459,7 +473,7 @@ ecsactsi_wasm_error ecsactsi_wasm_load(
 		std::unique_lock lk(modules_mutex);
 		for(auto&& [system_id, pending_info] : pending_modules) {
 			if(modules.contains(system_id)) {
-				// TODO(zaucy): Cleanup existing module info
+				unload_system_module(system_id, modules.at(system_id));
 			}
 
 			modules[system_id] = std::move(pending_info);
@@ -503,3 +517,27 @@ void ecsactsi_wasm_set_trap_handler(ecsactsi_wasm_trap_handler handler) {
 	std::shared_lock lk(modules_mutex);
 	trap_handler = handler;
 }
+
+void ecsactsi_wasm_unload(
+	int                    systems_count,
+	ecsact_system_like_id* system_ids
+) {
+	std::unique_lock lk(modules_mutex);
+	for(int i = 0; systems_count > i; ++i) {
+		auto system_id = system_ids[i];
+		auto module_itr = modules.find(system_id);
+		if(module_itr != modules.end()) {
+			unload_system_module(system_id, module_itr->second);
+			modules.erase(module_itr);
+		}
+	}
+}
+
+void ecsactsi_wasm_reset() {
+	std::unique_lock lk(modules_mutex);
+	for(auto&& [sys_id, m] : modules) {
+		unload_system_module(sys_id, m);
+	}
+	modules.clear();
+	trap_handler = nullptr;
+}
diff --git a/ecsactsi_wasm.h b/ecsactsi_wasm.h
index 874ccf9..72f068c 100644
--- a/ecsactsi_wasm.h
+++ b/ecsactsi_wasm.h
@@ -124,6 +124,24 @@ ECSACTSI_WASM_API_FN(ecsactsi_wasm_error, ecsactsi_wasm_load)
 	const char**           wasm_exports
 );
 
+/**
+ * Unload 1 or more systems. If a system is not already loaded this is a noop.
+ * @param systems_count number of systems impls to unload
+ * @param system_ids array of system IDs to unload. Sequential list length of
+ *        @p systems_count.
+ */
+ECSACTSI_WASM_API_FN(void, ecsactsi_wasm_unload)
+( //
+	int                    systems_count,
+	ecsact_system_like_id* system_ids
+);
+
+/**
+ * Reset state. Effectively called `ecsactsi_wasm_unload` for each system
+ * implementation and clears the trap handler.
+ */
+ECSACTSI_WASM_API_FN(void, ecsactsi_wasm_reset)();
+
 /**
  * @param system_id System ID associated with the impl that triggered the trap
  * @param trap_message The trap message contents. Null-terminated string.
diff --git a/wasm_ecsact_system_execution.h b/wasm_ecsact_system_execution.h
index f9f92ac..3628c22 100644
--- a/wasm_ecsact_system_execution.h
+++ b/wasm_ecsact_system_execution.h
@@ -17,7 +17,7 @@ struct ecsact_internal_execution_context_linked_list {
 struct ecsact_internal_wasm_system_module_info {
 	wasm_module_t*                                 system_module;
 	wasm_instance_t*                               instance;
-	const wasm_func_t*                             system_impl_func;
+	wasm_func_t*                                   system_impl_func;
 	wasm_memory_t*                                 system_impl_memory;
 	wasm_store_t*                                  store;
 	const ecsact_system_execution_context*         parent;