Implement hotloading

* This commit implements dltools.{c,h}: _A simple wrapper around libdl / dlfcn.h_
* Reload states when done initializing engine, if hotloading is enabled.
* Adds general function types for state functions.

1 files changed, 62 insertions, 0 deletions

diff --git a/src/dltools.c b/src/dltools.c
new file mode 100644
index 0000000..de7c83b
--- /dev/null
+++ b/src/dltools.c
@@ -0,0 +1,62 @@
+#include <stdbool.h>
+#include <stdlib.h>
+
+#if defined (_WIN32) || defined (__WIN32__) || defined (WIN32)
+	/* include winapi */
+#else
+#include <dlfcn.h>
+#endif
+
+#include <engine/logging.h>
+#include <engine/dltools.h>
+
+bool
+dynamic_library_close(void* shared_library) {
+#if defined (_WIN32) || defined (__WIN32__) || defined (WIN32)
+	return true;
+#else
+	return dlclose(shared_library) == 0;
+#endif
+}
+
+void*
+dynamic_library_open(const char *library_path) {
+#if defined (_WIN32) || defined (__WIN32__) || defined (WIN32)
+	return NULL;
+#else
+	return dlopen(library_path, RTLD_NOW);
+#endif
+}
+
+char* dynamic_library_get_error(void) {
+#if defined (_WIN32) || defined (__WIN32__) || defined (WIN32)
+	return "unsupported on windows";
+#else
+	return dlerror();
+#endif
+}
+
+void*
+dynamic_library_reload(void* shared_library, const char *library_path) {
+	void* library_address = NULL;
+	if (!dynamic_library_close(shared_library)) {
+		ERROR("Failed to close shared library: %s", dynamic_library_get_error());
+		ERROR("Reloading dynamic library failed.");
+		return library_address;
+	}
+	if ((library_address = dynamic_library_open(library_path)) == NULL) {
+		ERROR("Failed to open shared library: %s", dynamic_library_get_error());
+		ERROR("Reloading dynamic library %s failed.", library_path);
+	}
+	return library_address;
+}
+
+
+void*
+dynamic_library_get_symbol(void *restrict shared_library, const char *symbol) {
+#if defined (_WIN32) || defined (__WIN32__) || defined (WIN32)
+	return NULL;
+#else
+	return dlsym(shared_library, symbol);
+#endif
+}