1 files changed, 82 insertions, 0 deletions
diff --git a/src/jvm/jvm.h b/src/jvm/jvm.h
new file mode 100644
index 0000000..cc69cb4
--- /dev/null
+++ b/src/jvm/jvm.h
@@ -0,0 +1,82 @@
+#pragma once
+
+#include "jni.h"
+#include <stdbool.h>
+
+struct jvm_string {
+   const char *data;
+   size_t size;
+   bool heap; // if on heap, then `data` should be freed
+};
+
+struct jvm_array {
+   void *data;
+   size_t element_sz, size; // `size` == in elements, `size * element_sz` for bytes
+};
+
+struct jvm_class {
+   struct jvm_string name;
+};
+
+struct jvm_method {
+   jclass klass;
+   struct jvm_string name, signature;
+};
+
+struct jvm_object {
+   jclass this_klass;
+
+   union {
+      struct jvm_array array;
+      struct jvm_method method;
+      struct jvm_class klass;
+      struct jvm_string string;
+   };
+
+   enum jvm_object_type {
+      JVM_OBJECT_NONE,
+      JVM_OBJECT_OPAQUE,
+      JVM_OBJECT_ARRAY,
+      JVM_OBJECT_METHOD,
+      JVM_OBJECT_CLASS,
+      JVM_OBJECT_STRING,
+      JVM_OBJECT_LAST,
+   } type;
+};
+
+struct jvm_native_method {
+   struct jvm_method method;
+   void *function;
+};
+
+struct jvm {
+   // [0] object is created on `jvm_init` and it's a class object for defining the class of a class
+   // every class object's `this_class` member points back to [0], causing recursion.
+   // Every other object or class definition is created lazily as needed, only [0] is special.
+   // `jobject`'s we return through JNI are actually (index+1) to this array, not pointers.
+   struct jvm_object objects[256];
+
+   // Native methods registered by the application.
+   // Nothing special, but there's no need to access this array either really.
+   // You can use `jvm_get_native_method` instead.
+   struct jvm_native_method methods[255];
+
+   // These hold the function pointers for our JNI implementation.
+   struct JNINativeInterface native;
+   struct JNIInvokeInterface invoke;
+
+   // JNI's api is weird.. pointer to a reference of a struct, OK!
+   // Developers have to dereference these pointers to call methods from an ... reference.
+   // NOTE: These are pointers, and JNI interface passes pointers to these pointers!
+   JNIEnv env; // points to native
+   JavaVM vm; // points to invoke
+};
+
+void*
+jvm_get_native_method(struct jvm *jvm, const char *klass, const char *method);
+
+void
+jvm_release(struct jvm *jvm);
+
+void
+jvm_init(struct jvm *jvm);