Support passing trait instance references from C to Java without clone or double...
[ldk-java] / gen_type_mapping.py
index bf9c78b83458ff9f94b654afcd4603aab5135793..81bb0f99b8ebcaa5236073fa627514c8d224a212 100644 (file)
@@ -16,10 +16,21 @@ class TypeMappingGenerator:
 
     def map_type(self, fn_arg, print_void, ret_arr_len, is_free, holds_ref):
         ty_info = self.java_c_types(fn_arg, ret_arr_len)
-        mapped_info = self.map_type_with_info(ty_info, print_void, ret_arr_len, is_free, holds_ref)
+        mapped_info = self.map_type_with_info(ty_info, print_void, ret_arr_len, is_free, holds_ref, False)
         return mapped_info
 
-    def map_type_with_info(self, ty_info, print_void, ret_arr_len, is_free, holds_ref):
+    def map_nullable_type(self, fn_arg, print_void, ret_arr_len, is_free, holds_ref):
+        ty_info = self.java_c_types(fn_arg, ret_arr_len)
+        mapped_info = self.map_type_with_info(ty_info, print_void, ret_arr_len, is_free, holds_ref, True)
+        return mapped_info
+
+    def map_type_with_info(self, ty_info, print_void, ret_arr_len, is_free, holds_ref, is_nullable):
+        mapped_info = self._do_map_type_with_info(ty_info, print_void, ret_arr_len, is_free, holds_ref, is_nullable)
+        if is_nullable:
+            mapped_info.nullable = True
+        return mapped_info
+
+    def _do_map_type_with_info(self, ty_info, print_void, ret_arr_len, is_free, holds_ref, is_nullable):
         if ty_info.c_ty == "void":
             if not print_void:
                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
@@ -85,7 +96,7 @@ class TypeMappingGenerator:
                     # function itself, resulting in a segfault. Thus, we manually check and ensure we don't clone for
                     # ChannelMonitors inside of vecs.
                     ty_info.subty.requires_clone = False
-                subty = self.map_type_with_info(ty_info.subty, False, None, is_free, holds_ref)
+                subty = self.map_type_with_info(ty_info.subty, False, None, is_free, holds_ref, False)
                 arg_conv = ty_info.rust_obj + " " + arr_name + "_constr;\n"
                 pf = ""
                 if ty_info.is_ptr:
@@ -127,32 +138,43 @@ class TypeMappingGenerator:
                 if ty_info.is_ptr:
                     arg_conv += "\n\t" + arr_name + "_ptr = &" + arr_name + "_constr;\n}"
 
-                ret_conv = (ty_info.rust_obj + " " + arr_name + "_var = ", "")
+                if is_nullable:
+                    ret_conv = (ty_info.rust_obj + " *" + arr_name + "_var_ptr = ", "")
+                else:
+                    ret_conv = (ty_info.rust_obj + " " + arr_name + "_var = ", "")
                 if subty.ret_conv is None:
                     ret_conv = ("DUMMY", "DUMMY")
                 else:
-                    ret_conv = (ret_conv[0], ";\n" + ty_info.c_ty + " " + arr_name + "_arr = " + self.consts.create_native_arr_call(arr_name + "_var." + arr_len, ty_info) + ";\n")
+                    ret_conv = (ret_conv[0], ";\n" + ty_info.c_ty + " " + arr_name + "_arr = NULL;\n")
+                    indent = ""
+                    if is_nullable:
+                        ret_conv = (ret_conv[0], ret_conv[1] + "if (" + arr_name + " != NULL) {\n")
+                        ret_conv = (ret_conv[0], ret_conv[1] + "\t" + ty_info.rust_obj + " " + arr_name + "_var = *" + arr_name + "_var_ptr;\n")
+                        indent = "\t"
+                    ret_conv = (ret_conv[0], ret_conv[1] + indent + arr_name + "_arr = " + self.consts.create_native_arr_call(arr_name + "_var." + arr_len, ty_info) + ";\n")
                     get_ptr_call = self.consts.get_native_arr_ptr_call(ty_info)
                     if get_ptr_call is not None:
-                        ret_conv = (ret_conv[0], ret_conv[1] + subty.c_ty + " *" + arr_name + "_arr_ptr = " + get_ptr_call[0] + arr_name + "_arr" + get_ptr_call[1] + ";\n")
-                    ret_conv = (ret_conv[0], ret_conv[1] + "for (size_t " + idxc + " = 0; " + idxc + " < " + arr_name + "_var." + arr_len + "; " + idxc + "++) {\n")
-                    ret_conv = (ret_conv[0], ret_conv[1] + "\t" + subty.ret_conv[0].replace("\n", "\n\t"))
-                    ret_conv = (ret_conv[0], ret_conv[1] + arr_name + "_var." + ty_info.arr_access + "[" + idxc + "]" + subty.ret_conv[1].replace("\n", "\n\t"))
+                        ret_conv = (ret_conv[0], ret_conv[1] + indent + subty.c_ty + " *" + arr_name + "_arr_ptr = " + get_ptr_call[0] + arr_name + "_arr" + get_ptr_call[1] + ";\n")
+                    ret_conv = (ret_conv[0], ret_conv[1] + indent + "for (size_t " + idxc + " = 0; " + idxc + " < " + arr_name + "_var." + arr_len + "; " + idxc + "++) {\n")
+                    ret_conv = (ret_conv[0], ret_conv[1] + indent + "\t" + subty.ret_conv[0].replace("\n", "\n\t" + indent))
+                    ret_conv = (ret_conv[0], ret_conv[1] + indent + arr_name + "_var." + ty_info.arr_access + "[" + idxc + "]" + subty.ret_conv[1].replace("\n", "\n\t" + indent) + "\n")
                     if get_ptr_call is not None:
-                        ret_conv = (ret_conv[0], ret_conv[1] + "\n\t" + arr_name + "_arr_ptr[" + idxc + "] = " + subty.ret_conv_name + ";\n}")
+                        ret_conv = (ret_conv[0], ret_conv[1] + indent + "\t" + arr_name + "_arr_ptr[" + idxc + "] = " + subty.ret_conv_name + ";\n" + indent + "}\n")
                     else:
-                        ret_conv = (ret_conv[0], ret_conv[1] + "\n\t" + self.consts.get_native_arr_entry_call(ty_info, arr_name + "_arr", idxc, subty.ret_conv_name) + ";\n}")
+                        ret_conv = (ret_conv[0], ret_conv[1] + indent + "\t" + self.consts.get_native_arr_entry_call(ty_info, arr_name + "_arr", idxc, subty.ret_conv_name) + ";\n" + indent + "}\n")
                     cleanup = self.consts.release_native_arr_ptr_call(ty_info, arr_name + "_arr", arr_name + "_arr_ptr")
                     if cleanup is not None:
-                        ret_conv = (ret_conv[0], ret_conv[1] + "\n" + cleanup + ";")
-                if not holds_ref:
-                    # XXX: The commented if's are a bit smarter freeing, but we need to be a nudge smarter still
-                    # Note that we don't drop the full vec here - we're passing ownership to java (or have cloned) or free'd by now!
-                    ret_conv = (ret_conv[0], ret_conv[1] + "\nFREE(" + arr_name + "_var." + ty_info.arr_access + ");")
-                    #if subty.rust_obj is not None and subty.rust_obj in self.opaque_structs:
-                    #    ret_conv = (ret_conv[0], ret_conv[1] + "\nFREE(" + arr_name + "_var." + ty_info.arr_access + ");")
-                    #else:
-                    #    ret_conv = (ret_conv[0], ret_conv[1] + "\n" + ty_info.rust_obj.replace("LDK", "") + "_free(" + arr_name + "_var);")
+                        ret_conv = (ret_conv[0], ret_conv[1] + indent + cleanup + ";")
+                    if not holds_ref and not is_nullable:
+                        # XXX: The commented if's are a bit smarter freeing, but we need to be a nudge smarter still
+                        # Note that we don't drop the full vec here - we're passing ownership to java (or have cloned) or free'd by now!
+                        ret_conv = (ret_conv[0], ret_conv[1] + "\n" + indent + "FREE(" + arr_name + "_var." + ty_info.arr_access + ");")
+                        #if subty.rust_obj is not None and subty.rust_obj in self.opaque_structs:
+                        #    ret_conv = (ret_conv[0], ret_conv[1] + "\nFREE(" + arr_name + "_var." + ty_info.arr_access + ");")
+                        #else:
+                        #    ret_conv = (ret_conv[0], ret_conv[1] + "\n" + ty_info.rust_obj.replace("LDK", "") + "_free(" + arr_name + "_var);")
+                    if is_nullable:
+                        ret_conv = (ret_conv[0], ret_conv[1] + "\n}")
 
                 to_hu_conv = None
                 to_hu_conv_name = None
@@ -185,6 +207,7 @@ class TypeMappingGenerator:
                     arg_conv = arg_conv, arg_conv_name = arg_conv_name, arg_conv_cleanup = arg_conv_cleanup,
                     ret_conv = ret_conv, ret_conv_name = arr_name + "_arr", to_hu_conv = to_hu_conv, to_hu_conv_name = to_hu_conv_name, from_hu_conv = from_hu_conv)
         elif ty_info.java_ty == "String":
+            assert not is_nullable
             if not is_free:
                 arg_conv = "LDKStr " + ty_info.var_name + "_conv = " + self.consts.str_ref_to_c_call(ty_info.var_name) + ";"
                 arg_conv_name = ty_info.var_name + "_conv"
@@ -221,6 +244,7 @@ class TypeMappingGenerator:
                     arg_conv = None, arg_conv_name = "arg", arg_conv_cleanup = None,
                     ret_conv = None, ret_conv_name = None, to_hu_conv = "TODO 8", to_hu_conv_name = None, from_hu_conv = None)
         elif ty_info.is_native_primitive:
+            assert not is_nullable
             return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                 arg_conv = None, arg_conv_name = ty_info.var_name, arg_conv_cleanup = None,
                 ret_conv = None, ret_conv_name = None, to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)
@@ -240,6 +264,7 @@ class TypeMappingGenerator:
                     if (ty_info.rust_obj.replace("LDK", "") + "_clone") in self.clone_fns:
                         # TODO: This is a bit too naive, even with the checks above, we really need to know if rust wants a ref or not, not just if its pass as a ptr.
                         opaque_arg_conv = opaque_arg_conv + "\n" + ty_info.var_name + "_conv = " + ty_info.rust_obj.replace("LDK", "") + "_clone(&" + ty_info.var_name + "_conv);"
+                        from_hu_conv = (from_hu_conv[0], "")
                     elif ty_info.passed_as_ptr:
                         opaque_arg_conv = opaque_arg_conv + "\n// Warning: we need a move here but no clone is available for " + ty_info.rust_obj
                         # TODO: Once we support features cloning (which just isn't in C yet), we can make this a compile error instead!
@@ -253,27 +278,37 @@ class TypeMappingGenerator:
                             "// Thus, after this call, " + ty_info.var_name + " is reset to null and is now a dummy object.\n" + ty_info.var_name + ".ptr = 0")
 
                 opaque_ret_conv_suf = ";\n"
+                opaque_ret_conv_suf += "uint64_t " + ty_info.var_name + "_ref = 0;\n"
+                indent = ""
+                if is_nullable:
+                    opaque_ret_conv_suf += "if ((uint64_t)" + ty_info.var_name + "_var.inner > 4096) {\n"
+                    indent = "\t"
                 if not holds_ref and ty_info.is_ptr and (ty_info.rust_obj.replace("LDK", "") + "_clone") in self.clone_fns: # is_ptr, not holds_ref implies passing a pointed-to value to java, which needs copied
-                    opaque_ret_conv_suf = opaque_ret_conv_suf + ty_info.var_name + "_var = " + ty_info.rust_obj.replace("LDK", "") + "_clone(" + ty_info.var_name + ");\n"
+                    opaque_ret_conv_suf += indent + ty_info.var_name + "_var = " + ty_info.rust_obj.replace("LDK", "") + "_clone(" + ty_info.var_name + ");\n"
                 elif not holds_ref and ty_info.is_ptr:
-                    opaque_ret_conv_suf = opaque_ret_conv_suf + "// Warning: we may need a move here but no clone is available for " + ty_info.rust_obj + "\n"
+                    opaque_ret_conv_suf += indent + "// Warning: we may need a move here but no clone is available for " + ty_info.rust_obj + "\n"
 
-                opaque_ret_conv_suf = opaque_ret_conv_suf + "CHECK((((uint64_t)" + ty_info.var_name + "_var.inner) & 1) == 0); // We rely on a free low bit, malloc guarantees this.\n"
-                opaque_ret_conv_suf = opaque_ret_conv_suf + "CHECK((((uint64_t)&" + ty_info.var_name + "_var) & 1) == 0); // We rely on a free low bit, pointer alignment guarantees this.\n"
+                opaque_ret_conv_suf += indent + "CHECK((((uint64_t)" + ty_info.var_name + "_var.inner) & 1) == 0); // We rely on a free low bit, malloc guarantees this.\n"
+                opaque_ret_conv_suf += indent + "CHECK((((uint64_t)&" + ty_info.var_name + "_var) & 1) == 0); // We rely on a free low bit, pointer alignment guarantees this.\n"
                 if holds_ref:
-                    opaque_ret_conv_suf = opaque_ret_conv_suf + "uint64_t " + ty_info.var_name + "_ref = (uint64_t)" + ty_info.var_name + "_var.inner & ~1;"
+                    opaque_ret_conv_suf += indent + ty_info.var_name + "_ref = (uint64_t)" + ty_info.var_name + "_var.inner & ~1;"
                 else:
-                    opaque_ret_conv_suf = opaque_ret_conv_suf + "uint64_t " + ty_info.var_name + "_ref = (uint64_t)" + ty_info.var_name + "_var.inner;\n"
-                    opaque_ret_conv_suf = opaque_ret_conv_suf + "if (" + ty_info.var_name + "_var.is_owned) {\n"
-                    opaque_ret_conv_suf = opaque_ret_conv_suf + "\t" + ty_info.var_name + "_ref |= 1;\n"
-                    opaque_ret_conv_suf = opaque_ret_conv_suf + "}"
+                    opaque_ret_conv_suf += indent + ty_info.var_name + "_ref = (uint64_t)" + ty_info.var_name + "_var.inner;\n"
+                    opaque_ret_conv_suf += indent + "if (" + ty_info.var_name + "_var.is_owned) {\n"
+                    opaque_ret_conv_suf += indent + "\t" + ty_info.var_name + "_ref |= 1;\n"
+                    opaque_ret_conv_suf += indent + "}"
+                if is_nullable:
+                    opaque_ret_conv_suf += "\n}"
 
+                to_hu_conv_sfx = ""
+                if not ty_info.is_ptr or holds_ref:
+                    to_hu_conv_sfx = "\n" + ty_info.var_name + "_hu_conv.ptrs_to.add(this);"
                 if ty_info.is_ptr:
                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                         arg_conv = opaque_arg_conv, arg_conv_name = "&" + ty_info.var_name + "_conv", arg_conv_cleanup = None,
                         ret_conv = (ty_info.rust_obj + " " + ty_info.var_name + "_var = *", opaque_ret_conv_suf),
                         ret_conv_name = ty_info.var_name + "_ref",
-                        to_hu_conv = self.consts.to_hu_conv_templates['ptr'].replace('{human_type}', ty_info.java_hu_ty).replace('{var_name}', ty_info.var_name),
+                        to_hu_conv = self.consts.to_hu_conv_templates['ptr'].replace('{human_type}', ty_info.java_hu_ty).replace('{var_name}', ty_info.var_name) + to_hu_conv_sfx,
                         to_hu_conv_name = ty_info.var_name + "_hu_conv",
                         from_hu_conv = from_hu_conv)
                 else:
@@ -281,10 +316,11 @@ class TypeMappingGenerator:
                         arg_conv = opaque_arg_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
                         ret_conv = (ty_info.rust_obj + " " + ty_info.var_name + "_var = ", opaque_ret_conv_suf),
                         ret_conv_name = ty_info.var_name + "_ref",
-                        to_hu_conv = self.consts.to_hu_conv_templates['default'].replace('{human_type}', ty_info.java_hu_ty).replace('{var_name}', ty_info.var_name) + "\n" + ty_info.var_name + "_hu_conv.ptrs_to.add(this);",
+                        to_hu_conv = self.consts.to_hu_conv_templates['default'].replace('{human_type}', ty_info.java_hu_ty).replace('{var_name}', ty_info.var_name) + to_hu_conv_sfx,
                         to_hu_conv_name = ty_info.var_name + "_hu_conv",
                         from_hu_conv = from_hu_conv)
 
+            assert not is_nullable
             if not ty_info.is_ptr:
                 if ty_info.rust_obj in self.unitary_enums:
                     (ret_pfx, ret_sfx) = self.consts.c_unitary_enum_to_native_call(ty_info)
@@ -295,14 +331,17 @@ class TypeMappingGenerator:
                         arg_conv_cleanup = None,
                         ret_conv = (ty_info.c_ty + " " + ty_info.var_name + "_conv = " + ret_pfx, ret_sfx + ";"),
                         ret_conv_name = ty_info.var_name + "_conv", to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)
-                base_conv = ty_info.rust_obj + " " + ty_info.var_name + "_conv = *(" + ty_info.rust_obj + "*)(((uint64_t)" + ty_info.var_name + ") & ~1);"
+                base_conv = "void* " + ty_info.var_name + "_ptr = (void*)(((uint64_t)" + ty_info.var_name + ") & ~1);\n"
+                base_conv += "CHECK_ACCESS(" + ty_info.var_name + "_ptr);\n"
+                base_conv += ty_info.rust_obj + " " + ty_info.var_name + "_conv = *(" + ty_info.rust_obj + "*)(" + ty_info.var_name + "_ptr);"
                 if ty_info.rust_obj in self.trait_structs:
-                    ret_conv = (ty_info.rust_obj + "* " + ty_info.var_name + "_ret =MALLOC(sizeof(" + ty_info.rust_obj + "), \"" + ty_info.rust_obj + "\");\n*" + ty_info.var_name + "_ret = ", ";")
+                    ret_conv = (ty_info.rust_obj + "* " + ty_info.var_name + "_ret = MALLOC(sizeof(" + ty_info.rust_obj + "), \"" + ty_info.rust_obj + "\");\n*" + ty_info.var_name + "_ret = ", ";")
                     if holds_ref:
                         if (ty_info.rust_obj.replace("LDK", "") + "_clone") in self.clone_fns:
                             ret_conv = (ret_conv[0] + ty_info.rust_obj.replace("LDK", "") + "_clone(&", ");")
                         else:
-                            ret_conv = (ret_conv[0], "; // Warning: We likely need to clone here, but no clone is available for " + ty_info.rust_obj)
+                            ret_conv = (ret_conv[0], ";\n// Warning: We likely need to clone here, but no clone is available, so we just do it for Java instances")
+                            ret_conv = (ret_conv[0], ret_conv[1] + "" + self.consts.trait_struct_inc_refcnt(ty_info).replace(ty_info.var_name + "_conv", "(*" + ty_info.var_name + "_ret)"))
                     if not is_free:
                         needs_full_clone = not is_free and (not ty_info.is_ptr and not holds_ref or ty_info.requires_clone == True) and ty_info.requires_clone != False
                         if needs_full_clone and (ty_info.rust_obj.replace("LDK", "") + "_clone") in self.clone_fns:
@@ -332,17 +371,23 @@ class TypeMappingGenerator:
                     # underlying unlike Vecs, and it gives Java more freedom.
                     base_conv = base_conv + "\nFREE((void*)" + ty_info.var_name + ");"
                 if ty_info.rust_obj in self.complex_enums:
+                    if needs_full_clone and (ty_info.rust_obj.replace("LDK", "") + "_clone") not in self.clone_fns:
+                        # We really need a full clone here, but for now we just implement
+                        # a manual clone explicitly for Option<Trait>s
+                        if ty_info.rust_obj.startswith("LDKCOption"):
+                            optional_ty = ty_info.rust_obj[11:-1]
+                            if "LDK" + optional_ty in self.trait_structs:
+                                base_conv += "\nif (" + ty_info.var_name + "_conv.tag == " + ty_info.rust_obj + "_Some) {"
+                                base_conv += "\n\t// Manually implement clone for Java trait instances"
+                                optional_ty_info = self.java_c_types("LDK" + optional_ty + " " + ty_info.var_name, None)
+                                base_conv += self.consts.trait_struct_inc_refcnt(optional_ty_info).\
+                                    replace("\n", "\n\t").replace(ty_info.var_name + "_conv", ty_info.var_name + "_conv.some")
+                                base_conv += "\n}"
                     ret_conv = ("uint64_t " + ty_info.var_name + "_ref = ((uint64_t)&", ") | 1;")
                     if not holds_ref:
                         ret_conv = (ty_info.rust_obj + " *" + ty_info.var_name + "_copy = MALLOC(sizeof(" + ty_info.rust_obj + "), \"" + ty_info.rust_obj + "\");\n", "")
-                        if ty_info.requires_clone == True: # Set in object array mapping
-                            if (ty_info.rust_obj.replace("LDK", "") + "_clone") in self.clone_fns:
-                                ret_conv = (ret_conv[0] + "*" + ty_info.var_name + "_copy = " + ty_info.rust_obj.replace("LDK", "") + "_clone(&", ");\n")
-                            else:
-                                ret_conv = (ret_conv[0] + "*" + ty_info.var_name + "_copy = ", "; // Warning: We likely need to clone here, but no clone is available for " + ty_inf.rust_obj + "\n")
-                        else:
-                            ret_conv = (ret_conv[0] + "*" + ty_info.var_name + "_copy = ", ";\n")
-                        ret_conv = (ret_conv[0], ret_conv[1] + "uint64_t " + ty_info.var_name + "_ref = (uint64_t)" + ty_info.var_name + "_copy;")
+                        ret_conv = (ret_conv[0] + "*" + ty_info.var_name + "_copy = ", "")
+                        ret_conv = (ret_conv[0], ";\nuint64_t " + ty_info.var_name + "_ref = (uint64_t)" + ty_info.var_name + "_copy;")
                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                         arg_conv = base_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
                         ret_conv = ret_conv, ret_conv_name = ty_info.var_name + "_ref",
@@ -362,60 +407,27 @@ class TypeMappingGenerator:
                         to_hu_conv = ty_info.java_hu_ty + " " + ty_info.var_name + "_hu_conv = " + ty_info.java_hu_ty + ".constr_from_ptr(" + ty_info.var_name + ");",
                         to_hu_conv_name = ty_info.var_name + "_hu_conv", from_hu_conv = (ty_info.var_name + " != null ? " + ty_info.var_name + ".ptr : 0", ""))
                 if ty_info.rust_obj in self.tuple_types:
-                    from_hu_conv_sfx = ""
-                    from_hu_conv = "bindings." + self.tuple_types[ty_info.rust_obj][1].replace("LDK", "") + "_new("
-                    to_hu_conv_pfx = ""
-                    to_hu_conv_sfx = ty_info.java_hu_ty + " " + ty_info.var_name + "_conv = new " + ty_info.java_hu_ty + "("
-                    to_hu_conv_refs = ""
-                    for idx, conv in enumerate(self.tuple_types[ty_info.rust_obj][0]):
-                        if idx != 0:
-                            to_hu_conv_sfx = to_hu_conv_sfx + ", "
-                            from_hu_conv = from_hu_conv + ", "
-                        conv.var_name = ty_info.var_name + "_" + chr(idx + ord("a"))
-                        conv_map = self.map_type_with_info(conv, False, None, is_free, holds_ref)
-                        to_hu_conv_pfx = to_hu_conv_pfx + conv.java_ty + " " + ty_info.var_name + "_" + chr(idx + ord("a")) + " = "
-                        if not conv.is_native_primitive and (conv_map.rust_obj.replace("LDK", "") + "_clone") in self.clone_fns and conv_map.rust_obj == "LDKTxOut":
-                            to_hu_conv_pfx = to_hu_conv_pfx + "bindings." + conv_map.rust_obj.replace("LDK", "") + "_clone("
-                        to_hu_conv_pfx = to_hu_conv_pfx + "bindings." + self.tuple_types[ty_info.rust_obj][1] + "_get_" + chr(idx + ord("a")) + "(" + ty_info.var_name + ")"
-                        if not conv.is_native_primitive and (conv_map.rust_obj.replace("LDK", "") + "_clone") in self.clone_fns and conv_map.rust_obj == "LDKTxOut": # XXX
-                            to_hu_conv_pfx = to_hu_conv_pfx + ")"
-                        to_hu_conv_pfx = to_hu_conv_pfx + ";\n"
-                        if conv_map.to_hu_conv is not None:
-                            to_hu_conv_pfx = to_hu_conv_pfx + conv_map.to_hu_conv + ";\n"
-                            to_hu_conv_sfx = to_hu_conv_sfx + conv_map.to_hu_conv_name
-                            if to_hu_conv_refs is not None:
-                                if conv_map.c_ty.endswith("Array"):
-                                    to_hu_conv_refs = None
-                                else:
-                                    to_hu_conv_refs = to_hu_conv_refs + "\n" + conv_map.to_hu_conv_name + ".ptrs_to.add(" + ty_info.var_name + "_conv);"
-                        else:
-                            to_hu_conv_sfx = to_hu_conv_sfx + ty_info.var_name + "_" + chr(idx + ord("a"))
-                        if conv_map.from_hu_conv is not None:
-                            from_hu_conv = from_hu_conv + conv_map.from_hu_conv[0].replace(ty_info.var_name + "_" + chr(idx + ord("a")), ty_info.var_name + "." + chr(idx + ord("a")))
-                            if conv_map.from_hu_conv[1] != "":
-                                from_hu_conv_sfx = from_hu_conv_sfx + conv_map.from_hu_conv[1].replace(conv.var_name, ty_info.var_name + "." + chr(idx + ord("a")))
-                                if idx != len(self.tuple_types[ty_info.rust_obj][0]) - 1:
-                                    from_hu_conv_sfx += "; "
+                    ret_conv_name = "((uint64_t)" + ty_info.var_name + "_conv)"
+                    if holds_ref:
+                        # If we're trying to return a ref, we have to clone.
+                        if (ty_info.rust_obj.replace("LDK", "") + "_clone") not in self.clone_fns:
+                            ret_conv = (ty_info.rust_obj + "* " + ty_info.var_name + "_conv = &", "")
+                            ret_conv = (ret_conv[0], ";\n// Warning: we really need to clone here, but no clone is available for " + ty_info.rust_obj)
+                            ret_conv_name += " | 1"
                         else:
-                            from_hu_conv = from_hu_conv + ty_info.var_name + "." + chr(idx + ord("a"))
-
-                    if to_hu_conv_refs is None:
-                        to_hu_conv = to_hu_conv_pfx + to_hu_conv_sfx + ");\n// Warning: We may not free the C tuple object!"
+                            ret_conv = (ty_info.rust_obj + "* " + ty_info.var_name + "_conv = MALLOC(sizeof(" + ty_info.rust_obj + "), \"" + ty_info.rust_obj + "\");\n*" + ty_info.var_name + "_conv = ", ";")
+                            ret_conv = (ret_conv[0], ret_conv[1] + "\n*" + ty_info.var_name + "_conv = " + ty_info.rust_obj.replace("LDK", "") + "_clone(" + ty_info.var_name + "_conv);")
                     else:
-                        to_hu_conv = to_hu_conv_pfx + to_hu_conv_sfx + ", () -> {\n"
-                        to_hu_conv = to_hu_conv + "\tbindings." + ty_info.rust_obj.replace("LDK", "") + "_free(" + ty_info.var_name + ");\n"
-                        to_hu_conv = to_hu_conv + "});" + to_hu_conv_refs
-                    if not ty_info.is_ptr and not holds_ref:
-                        ret_conv = (ty_info.rust_obj + "* " + ty_info.var_name + "_ref = MALLOC(sizeof(" + ty_info.rust_obj + "), \"" + ty_info.rust_obj + "\");\n*" + ty_info.var_name + "_ref = ", ";")
-                        return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
-                            arg_conv = base_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
-                            ret_conv = ret_conv,
-                            ret_conv_name = "(uint64_t)" + ty_info.var_name + "_ref",
-                            to_hu_conv = to_hu_conv, to_hu_conv_name = ty_info.var_name + "_conv", from_hu_conv = (from_hu_conv + ")", from_hu_conv_sfx))
+                        ret_conv = (ty_info.rust_obj + "* " + ty_info.var_name + "_conv = MALLOC(sizeof(" + ty_info.rust_obj + "), \"" + ty_info.rust_obj + "\");\n*" + ty_info.var_name + "_conv = ", ";")
+                    if not ty_info.is_ptr or holds_ref:
+                        to_hu_conv_sfx = "\n" + ty_info.var_name + "_hu_conv.ptrs_to.add(this);"
+                    else:
+                        to_hu_conv_sfx = ""
                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                         arg_conv = base_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
-                        ret_conv = ("uint64_t " + ty_info.var_name + "_ref = (uint64_t)(&", ") | 1;"), ret_conv_name = ty_info.var_name + "_ref",
-                        to_hu_conv = to_hu_conv, to_hu_conv_name = ty_info.var_name + "_conv", from_hu_conv = (from_hu_conv + ")", from_hu_conv_sfx))
+                        ret_conv = ret_conv, ret_conv_name = ret_conv_name,
+                        to_hu_conv = ty_info.java_hu_ty + " " + ty_info.var_name + "_hu_conv = new " + ty_info.java_hu_ty + "(null, " + ty_info.var_name + ");" + to_hu_conv_sfx,
+                        to_hu_conv_name = ty_info.var_name + "_hu_conv", from_hu_conv = (ty_info.var_name + " != null ? " + ty_info.var_name + ".ptr : 0", ""))
 
                 # The manually-defined types - TxOut and u5
                 if ty_info.rust_obj == "LDKu5":
@@ -439,20 +451,24 @@ class TypeMappingGenerator:
                 assert(not is_free)
                 if ty_info.rust_obj in self.complex_enums:
                     ret_conv = ("uint64_t ret_" + ty_info.var_name + " = (uint64_t)", " | 1; // Warning: We should clone here!")
+                    from_hu_sfx = "this.ptrs_to.add(" + ty_info.var_name + ")"
                     if ty_info.rust_obj.replace("LDK", "") + "_clone" in self.clone_fns:
                         ret_conv_pfx = ty_info.rust_obj + " *ret_" + ty_info.var_name + " = MALLOC(sizeof(" + ty_info.rust_obj + "), \"" + ty_info.rust_obj + " ret conversion\");\n"
                         ret_conv_pfx += "*ret_" + ty_info.var_name + " = " + ty_info.rust_obj.replace("LDK", "") + "_clone("
                         ret_conv = (ret_conv_pfx, ");")
+                        from_hu_sfx = ""
                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                         arg_conv = ty_info.rust_obj + "* " + ty_info.var_name + "_conv = (" + ty_info.rust_obj + "*)" + ty_info.var_name + ";",
                         arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
                         ret_conv = ret_conv, ret_conv_name = "(uint64_t)ret_" + ty_info.var_name,
                         to_hu_conv = ty_info.java_hu_ty + " " + ty_info.var_name + "_hu_conv = " + ty_info.java_hu_ty + ".constr_from_ptr(" + ty_info.var_name + ");",
                         to_hu_conv_name = ty_info.var_name + "_hu_conv",
-                        from_hu_conv = (ty_info.var_name + " == null ? 0 : " + ty_info.var_name + ".ptr & ~1", "this.ptrs_to.add(" + ty_info.var_name + ")"))
+                        from_hu_conv = (ty_info.var_name + " == null ? 0 : " + ty_info.var_name + ".ptr & ~1", from_hu_sfx))
                 elif ty_info.rust_obj in self.trait_structs:
                     if ty_info.nonnull_ptr:
-                        arg_conv = ty_info.rust_obj + "* " + ty_info.var_name + "_conv = (" + ty_info.rust_obj + "*)(((uint64_t)" + ty_info.var_name + ") & ~1);"
+                        arg_conv = "void* " + ty_info.var_name + "_ptr = (void*)(((uint64_t)" + ty_info.var_name + ") & ~1);\n"
+                        arg_conv += "if (!(" + ty_info.var_name + " & 1)) { CHECK_ACCESS(" + ty_info.var_name + "_ptr); }\n"
+                        arg_conv += ty_info.rust_obj + "* " + ty_info.var_name + "_conv = (" + ty_info.rust_obj + "*)" + ty_info.var_name + "_ptr;"
                         arg_conv_name = ty_info.var_name + "_conv"
                     else:
                         # We map Option<Trait> as *mut Trait, which we can differentiate from &Trait by the NONNULL_PTR annotation.
@@ -460,7 +476,9 @@ class TypeMappingGenerator:
                         arg_conv = ty_info.rust_obj + " *" + ty_info.var_name + "_conv_ptr = NULL;\n"
                         arg_conv += "if (" + ty_info.var_name + " != 0) {\n"
                         arg_conv += "\t" + ty_info.rust_obj + " " + ty_info.var_name + "_conv;\n"
-                        arg_conv += "\t" + ty_info.var_name + "_conv = *(" + ty_info.rust_obj + "*)(((uint64_t)" + ty_info.var_name + ") & ~1);"
+                        arg_conv += "void* " + ty_info.var_name + "_ptr = (void*)(((uint64_t)" + ty_info.var_name + ") & ~1);\n"
+                        arg_conv += "CHECK_ACCESS(" + ty_info.var_name + "_ptr);\n"
+                        arg_conv += "\t" + ty_info.var_name + "_conv = *(" + ty_info.rust_obj + "*)" + ty_info.var_name + "_ptr;"
                         arg_conv += self.consts.trait_struct_inc_refcnt(ty_info).replace("\n", "\n\t")
                         arg_conv += "\n\t" + ty_info.var_name + "_conv_ptr = MALLOC(sizeof(" + ty_info.rust_obj + "), \"" + ty_info.rust_obj + "\");\n"
                         arg_conv += "\t*" + ty_info.var_name + "_conv_ptr = " + ty_info.var_name + "_conv;\n"
@@ -474,11 +492,12 @@ class TypeMappingGenerator:
                             ret_conv_name = "(uint64_t)" + ty_info.var_name + "_clone",
                             to_hu_conv = ty_info.java_hu_ty + " ret_hu_conv = new " + ty_info.java_hu_ty + "(null, " + ty_info.var_name + ");\nret_hu_conv.ptrs_to.add(this);",
                             to_hu_conv_name = "ret_hu_conv",
-                            from_hu_conv = (ty_info.var_name + " == null ? 0 : " + ty_info.var_name + ".ptr", "this.ptrs_to.add(" + ty_info.var_name + ")"))
+                            from_hu_conv = (ty_info.var_name + " == null ? 0 : " + ty_info.var_name + ".ptr", ""))
                     else:
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                             arg_conv = arg_conv, arg_conv_name = arg_conv_name, arg_conv_cleanup = None,
-                            ret_conv = ("uint64_t ret_" + ty_info.var_name + " = (uint64_t)", ";"), ret_conv_name = "ret_" + ty_info.var_name,
+                            ret_conv = ("// WARNING: This object doesn't live past this scope, needs clone!\nuint64_t ret_" + ty_info.var_name + " = ((uint64_t)", ") | 1;"),
+                            ret_conv_name = "ret_" + ty_info.var_name,
                             to_hu_conv = ty_info.java_hu_ty + " ret_hu_conv = new " + ty_info.java_hu_ty + "(null, " + ty_info.var_name + ");\nret_hu_conv.ptrs_to.add(this);",
                             to_hu_conv_name = "ret_hu_conv",
                             from_hu_conv = (ty_info.var_name + " == null ? 0 : " + ty_info.var_name + ".ptr", "this.ptrs_to.add(" + ty_info.var_name + ")"))