Add module ID tracking for hot-reloading

- Add stk_module_ids array to track module IDs by filename.
- extract_module_id() extracts module ID from it's filename.
- Enables tracking of file changes of already loaded modules.

src/module.c

@@ -1,5 +1,6 @@
 #include "stk.h"
 #include <stdlib.h>
+#include <string.h>
 
 void *platform_load_library(const char *path);
 void platform_unload_library(void *handle);
@@ -7,6 +8,7 @@ void *platform_get_symbol(void *handle, const char *symbol);
 
 typedef void (*stk_module_func)(void);
 
+static char **stk_module_ids = NULL;
 static void **stk_handles = NULL;
 static stk_module_func *stk_inits = NULL;
 static stk_module_func *stk_shutdowns = NULL;
@@ -15,6 +17,25 @@ size_t module_count = 0;
 
 size_t stk_module_count(void) { return module_count; }
 
+static char *extract_module_id(const char *path)
+{
+	char *id, *dot;
+	const char *basename = strrchr(path, '/');
+	if (!basename)
+		basename = path;
+	else
+		basename++;
+
+	id = malloc(strlen(basename) + 1);
+	strcpy(id, basename);
+
+	dot = strrchr(id, '.');
+	if (dot)
+		*dot = '\0';
+
+	return id;
+}
+
 int stk_module_load(const char *path)
 {
 	void *handle;
@@ -35,6 +56,7 @@ int stk_module_load(const char *path)
 		return -2;
 	}
 
+	stk_module_ids[module_count] = extract_module_id(path);
 	stk_handles[module_count] = handle;
 	stk_inits[module_count] = init_func;
 	stk_shutdowns[module_count] = shutdown_func;
@@ -53,6 +75,7 @@ void stk_module_unload(size_t index)
 	platform_unload_library(stk_handles[index]);
 
 	for (i = index; i < module_count - 1; ++i) {
+		stk_module_ids[i] = stk_module_ids[i + 1];
 		stk_handles[i] = stk_handles[i + 1];
 		stk_inits[i] = stk_inits[i + 1];
 		stk_shutdowns[i] = stk_shutdowns[i + 1];
@@ -63,10 +86,12 @@ void stk_module_unload(size_t index)
 
 void stk_module_free_memory(void)
 {
+	free(stk_module_ids);
 	free(stk_handles);
 	free(stk_inits);
 	free(stk_shutdowns);
 
+	stk_module_ids = NULL;
 	stk_handles = NULL;
 	stk_inits = NULL;
 	stk_shutdowns = NULL;
@@ -74,6 +99,7 @@ void stk_module_free_memory(void)
 
 int stk_module_init_memory(size_t capacity)
 {
+	stk_module_ids = malloc(capacity * sizeof(char *));
 	stk_handles = malloc(capacity * sizeof(void *));
 	stk_inits = malloc(capacity * sizeof(stk_module_func));
 	stk_shutdowns = malloc(capacity * sizeof(stk_module_func));