Merge pull request #114 from TheBlueMatt/main
[ldk-java] / gen_type_mapping.py
1 from bindingstypes import ConvInfo
2
3 class TypeMappingGenerator:
4
5     def __init__(self, java_c_types, consts, opaque_structs, clone_fns, unitary_enums, trait_structs, complex_enums, result_types, tuple_types):
6         # trick our way around circular imports
7         self.java_c_types = java_c_types
8         self.consts = consts
9         self.opaque_structs = opaque_structs
10         self.clone_fns = clone_fns
11         self.unitary_enums = unitary_enums
12         self.trait_structs = trait_structs
13         self.complex_enums = complex_enums
14         self.result_types = result_types
15         self.tuple_types = tuple_types
16
17     def map_type(self, fn_arg, print_void, ret_arr_len, is_free, holds_ref):
18         ty_info = self.java_c_types(fn_arg, ret_arr_len)
19         mapped_info = self.map_type_with_info(ty_info, print_void, ret_arr_len, is_free, holds_ref, False)
20         return mapped_info
21
22     def map_nullable_type(self, fn_arg, print_void, ret_arr_len, is_free, holds_ref):
23         ty_info = self.java_c_types(fn_arg, ret_arr_len)
24         mapped_info = self.map_type_with_info(ty_info, print_void, ret_arr_len, is_free, holds_ref, True)
25         return mapped_info
26
27     def map_type_with_info(self, ty_info, print_void, ret_arr_len, is_free, holds_ref, is_nullable):
28         mapped_info = self._do_map_type_with_info(ty_info, print_void, ret_arr_len, is_free, holds_ref, is_nullable)
29         if is_nullable:
30             mapped_info.nullable = True
31         return mapped_info
32
33     def _do_map_type_with_info(self, ty_info, print_void, ret_arr_len, is_free, holds_ref, is_nullable):
34         if ty_info.c_ty == "void":
35             if not print_void:
36                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
37                     arg_conv = None, arg_conv_name = None, arg_conv_cleanup = None,
38                     ret_conv = None, ret_conv_name = None, to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)
39         if ty_info.c_ty.endswith("Array"):
40             arr_len = ty_info.arr_len
41             if arr_len is not None:
42                 arr_name = ty_info.var_name
43             else:
44                 arr_name = "ret"
45                 arr_len = ret_arr_len
46             if ty_info.c_ty == "int8_tArray":
47                 (set_pfx, set_sfx) = self.consts.set_native_arr_contents(arr_name + "_arr", arr_len, ty_info)
48                 ret_conv = ("int8_tArray " + arr_name + "_arr = " + self.consts.create_native_arr_call(arr_len, ty_info) + ";\n" + set_pfx, "")
49                 arg_conv_cleanup = None
50                 if not arr_len.isdigit():
51                     arg_conv = ty_info.rust_obj + " " + arr_name + "_ref;\n"
52                     arg_conv = arg_conv + arr_name + "_ref." + arr_len + " = " +  self.consts.get_native_arr_len_call[0] + arr_name + self.consts.get_native_arr_len_call[1] + ";\n"
53                     if (not ty_info.is_ptr or not holds_ref) and ty_info.rust_obj != "LDKu8slice":
54                         arg_conv = arg_conv + arr_name + "_ref." + ty_info.arr_access + " = MALLOC(" + arr_name + "_ref." + arr_len + ", \"" + ty_info.rust_obj + " Bytes\");\n"
55                         arg_conv = arg_conv + self.consts.get_native_arr_contents(arr_name, arr_name + "_ref." + ty_info.arr_access, arr_name + "_ref." + arr_len, ty_info, True) + ";"
56                     else:
57                         arg_conv = arg_conv + arr_name + "_ref." + ty_info.arr_access + " = " + self.consts.get_native_arr_contents(arr_name, "NO_DEST", arr_name + "_ref." + arr_len, ty_info, False) + ";"
58                         arg_conv_cleanup = self.consts.cleanup_native_arr_ref_contents(arr_name, arr_name + "_ref." + ty_info.arr_access, arr_name + "_ref." + arr_len, ty_info)
59                     if ty_info.rust_obj == "LDKTransaction":
60                         arg_conv = arg_conv + "\n" + arr_name + "_ref.data_is_owned = " + str(holds_ref).lower() + ";"
61                     ret_conv = (ty_info.rust_obj + " " + arr_name + "_var = ", "")
62                     ret_conv = (ret_conv[0], ";\nint8_tArray " + arr_name + "_arr = " + self.consts.create_native_arr_call(arr_name + "_var." + arr_len, ty_info) + ";\n")
63                     (pfx, sfx) = self.consts.set_native_arr_contents(arr_name + "_arr", arr_name + "_var." + arr_len, ty_info)
64                     ret_conv = (ret_conv[0], ret_conv[1] + pfx + arr_name + "_var." + ty_info.arr_access + sfx + ";")
65                     if not holds_ref and ty_info.rust_obj != "LDKu8slice":
66                         ret_conv = (ret_conv[0], ret_conv[1] + "\n" + ty_info.rust_obj.replace("LDK", "") + "_free(" + arr_name + "_var);")
67                     from_hu_conv = self.consts.primitive_arr_from_hu(ty_info.subty, None, arr_name)
68                     to_hu_conv = self.consts.primitive_arr_to_hu(ty_info.subty, None, arr_name, arr_name + "_conv")
69                 elif ty_info.rust_obj is not None:
70                     arg_conv = ty_info.rust_obj + " " + arr_name + "_ref;\n"
71                     arg_conv = arg_conv + "CHECK(" + self.consts.get_native_arr_len_call[0] + arr_name + self.consts.get_native_arr_len_call[1] + " == " + arr_len + ");\n"
72                     arg_conv = arg_conv + self.consts.get_native_arr_contents(arr_name, arr_name + "_ref." + ty_info.arr_access, arr_len, ty_info, True) + ";"
73                     ret_conv = (ret_conv[0], "." + ty_info.arr_access + set_sfx + ";")
74                     from_hu_conv = self.consts.primitive_arr_from_hu(ty_info.subty, arr_len, arr_name)
75                     to_hu_conv = self.consts.primitive_arr_to_hu(ty_info.subty, None, arr_name, arr_name + "_conv")
76                 else:
77                     arg_conv = "unsigned char " + arr_name + "_arr[" + arr_len + "];\n"
78                     arg_conv = arg_conv + "CHECK(" + self.consts.get_native_arr_len_call[0] + arr_name + self.consts.get_native_arr_len_call[1] + " == " + arr_len + ");\n"
79                     arg_conv = arg_conv + self.consts.get_native_arr_contents(arr_name, arr_name + "_arr", arr_len, ty_info, True) + ";\n"
80                     arg_conv = arg_conv + "unsigned char (*" + arr_name + "_ref)[" + arr_len + "] = &" + arr_name + "_arr;"
81                     ret_conv = (ret_conv[0] + "*", set_sfx + ";")
82                     from_hu_conv = self.consts.primitive_arr_from_hu(ty_info.subty, arr_len, arr_name)
83                     to_hu_conv = self.consts.primitive_arr_to_hu(ty_info.subty, None, arr_name, arr_name + "_conv")
84                 to_hu_conv_name = None
85                 if to_hu_conv is not None:
86                     to_hu_conv_name = arr_name + "_conv"
87                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
88                     arg_conv = arg_conv, arg_conv_name = arr_name + "_ref", arg_conv_cleanup = arg_conv_cleanup,
89                     ret_conv = ret_conv, ret_conv_name = arr_name + "_arr",
90                     to_hu_conv = to_hu_conv, to_hu_conv_name = to_hu_conv_name,
91                     from_hu_conv = from_hu_conv)
92             else:
93                 assert not arr_len.isdigit() # fixed length arrays not implemented
94                 assert ty_info.java_hu_ty[len(ty_info.java_hu_ty) - 2:] == "[]"
95                 if arr_name == "":
96                     arr_name = "ret"
97                 conv_name = arr_name + "_conv_" + str(len(ty_info.java_hu_ty))
98                 idxc = chr(ord('a') + (len(ty_info.java_hu_ty) % 26))
99                 ty_info.subty.var_name = conv_name
100                 #XXX: We'd really prefer to only ever set to False, avoiding lots of clone, but need smarter free logic
101                 #if ty_info.is_ptr or holds_ref:
102                 #    ty_info.subty.requires_clone = False
103                 ty_info.subty.requires_clone = not ty_info.is_ptr or not holds_ref
104                 if not ty_info.subty.is_native_primitive and ty_info.subty.rust_obj == "LDKChannelMonitor":
105                     # We take a Vec of references to ChannelMonitors as input to ChannelManagerReadArgs, if we clone them,
106                     # we end up freeing the clones after creating the ChannelManagerReadArgs before calling the read
107                     # function itself, resulting in a segfault. Thus, we manually check and ensure we don't clone for
108                     # ChannelMonitors inside of vecs.
109                     ty_info.subty.requires_clone = False
110                 subty = self.map_type_with_info(ty_info.subty, False, None, is_free, holds_ref, False)
111                 arg_conv = ty_info.rust_obj + " " + arr_name + "_constr;\n"
112                 pf = ""
113                 if ty_info.is_ptr:
114                     pf = "\t"
115                     arg_conv += ty_info.rust_obj + " *" + arr_name + "_ptr = NULL;\n"
116                     arg_conv += "if (" + self.consts.is_arr_some_check[0] + arr_name + self.consts.is_arr_some_check[1] + ") {\n"
117                 arg_conv += pf + arr_name + "_constr." + arr_len + " = " + self.consts.get_native_arr_len_call[0] + arr_name + self.consts.get_native_arr_len_call[1] + ";\n"
118                 arg_conv += pf + "if (" + arr_name + "_constr." + arr_len + " > 0)\n"
119                 if subty.is_native_primitive:
120                     szof = subty.c_ty
121                 else:
122                     szof = subty.rust_obj
123                 arg_conv += pf + "\t" + arr_name + "_constr." + ty_info.arr_access + " = MALLOC(" + arr_name + "_constr." + arr_len + " * sizeof(" + szof + "), \"" + ty_info.rust_obj + " Elements\");\n"
124                 arg_conv += pf + "else\n"
125                 arg_conv += pf + "\t" + arr_name + "_constr." + ty_info.arr_access + " = NULL;\n"
126                 get_arr = self.consts.get_native_arr_contents(arr_name, "NO_DEST", arr_name + "_constr." + arr_len, ty_info, False)
127                 if get_arr != None:
128                     arg_conv += pf + subty.c_ty + "* " + arr_name + "_vals = " + get_arr + ";\n"
129                 arg_conv += pf + "for (size_t " + idxc + " = 0; " + idxc + " < " + arr_name + "_constr." + arr_len + "; " + idxc + "++) {\n"
130                 if get_arr != None:
131                     arg_conv += pf + "\t" + subty.c_ty + " " + conv_name + " = " + arr_name + "_vals[" + idxc + "];"
132                     if subty.arg_conv is not None:
133                         arg_conv += "\n\t" + pf + subty.arg_conv.replace("\n", "\n\t" + pf)
134                 else:
135                     arg_conv += pf + "\t" + subty.c_ty + " " + conv_name + " = " + self.consts.get_native_arr_elem(arr_name, idxc, ty_info) + ";\n"
136                     arg_conv += pf + "\t" + subty.arg_conv.replace("\n", "\n\t" + pf)
137                 arg_conv += "\n\t" + pf + arr_name + "_constr." + ty_info.arr_access + "[" + idxc + "] = " + subty.arg_conv_name + ";\n" + pf + "}"
138                 if get_arr != None:
139                     cleanup = self.consts.cleanup_native_arr_ref_contents(arr_name, arr_name + "_vals", arr_name + "_constr." + arr_len, ty_info)
140                     if cleanup is not None:
141                         arg_conv += "\n" + pf + cleanup + ";"
142                 if ty_info.is_ptr:
143                     arg_conv_name = arr_name + "_ptr"
144                 else:
145                     arg_conv_name = arr_name + "_constr"
146                 arg_conv_cleanup = None
147                 if ty_info.is_ptr:
148                     arg_conv_cleanup = "if (" + arr_name + "_ptr != NULL) { FREE(" + arr_name + "_constr." + ty_info.arr_access + "); }"
149                 if ty_info.is_ptr:
150                     arg_conv += "\n\t" + arr_name + "_ptr = &" + arr_name + "_constr;\n}"
151
152                 if is_nullable:
153                     ret_conv = (ty_info.rust_obj + " *" + arr_name + "_var_ptr = ", "")
154                 else:
155                     ret_conv = (ty_info.rust_obj + " " + arr_name + "_var = ", "")
156                 if subty.ret_conv is None:
157                     ret_conv = ("DUMMY", "DUMMY")
158                 else:
159                     ret_conv = (ret_conv[0], ";\n" + ty_info.c_ty + " " + arr_name + "_arr = NULL;\n")
160                     indent = ""
161                     if is_nullable:
162                         ret_conv = (ret_conv[0], ret_conv[1] + "if (" + arr_name + " != NULL) {\n")
163                         ret_conv = (ret_conv[0], ret_conv[1] + "\t" + ty_info.rust_obj + " " + arr_name + "_var = *" + arr_name + "_var_ptr;\n")
164                         indent = "\t"
165                     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")
166                     get_ptr_call = self.consts.get_native_arr_ptr_call(ty_info)
167                     if get_ptr_call is not None:
168                         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")
169                     ret_conv = (ret_conv[0], ret_conv[1] + indent + "for (size_t " + idxc + " = 0; " + idxc + " < " + arr_name + "_var." + arr_len + "; " + idxc + "++) {\n")
170                     ret_conv = (ret_conv[0], ret_conv[1] + indent + "\t" + subty.ret_conv[0].replace("\n", "\n\t" + indent))
171                     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")
172                     if get_ptr_call is not None:
173                         ret_conv = (ret_conv[0], ret_conv[1] + indent + "\t" + arr_name + "_arr_ptr[" + idxc + "] = " + subty.ret_conv_name + ";\n" + indent + "}\n")
174                     else:
175                         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")
176                     cleanup = self.consts.release_native_arr_ptr_call(ty_info, arr_name + "_arr", arr_name + "_arr_ptr")
177                     if cleanup is not None:
178                         ret_conv = (ret_conv[0], ret_conv[1] + indent + cleanup + ";")
179                     if not holds_ref and not is_nullable:
180                         # XXX: The commented if's are a bit smarter freeing, but we need to be a nudge smarter still
181                         # Note that we don't drop the full vec here - we're passing ownership to java (or have cloned) or free'd by now!
182                         ret_conv = (ret_conv[0], ret_conv[1] + "\n" + indent + "FREE(" + arr_name + "_var." + ty_info.arr_access + ");")
183                         #if subty.rust_obj is not None and subty.rust_obj in self.opaque_structs:
184                         #    ret_conv = (ret_conv[0], ret_conv[1] + "\nFREE(" + arr_name + "_var." + ty_info.arr_access + ");")
185                         #else:
186                         #    ret_conv = (ret_conv[0], ret_conv[1] + "\n" + ty_info.rust_obj.replace("LDK", "") + "_free(" + arr_name + "_var);")
187                     if is_nullable:
188                         ret_conv = (ret_conv[0], ret_conv[1] + "\n}")
189
190                 if subty.to_hu_conv is not None:
191                     to_hu_conv = self.consts.var_decl_statement(self.consts.c_type_map["uint32_t"][0], conv_name + "_len", self.consts.get_java_arr_len(arr_name)) + ";\n"
192                     to_hu_conv += self.consts.var_decl_statement(ty_info.java_hu_ty, conv_name + "_arr", self.consts.constr_hu_array(ty_info, conv_name + "_len"))
193                     to_hu_conv += ";\n" + self.consts.for_n_in_range(idxc, "0", conv_name + "_len") + "\n"
194                     to_hu_conv += "\t" + self.consts.var_decl_statement(subty.java_ty, conv_name, self.consts.get_java_arr_elem(subty, arr_name, idxc)) + ";\n"
195                     to_hu_conv += "\t" + subty.to_hu_conv.replace("\n", "\n\t") + "\n"
196                     to_hu_conv += "\t" + conv_name + "_arr[" + idxc + "] = " + subty.to_hu_conv_name + ";\n}"
197                     cleanup = self.consts.cleanup_converted_native_array(ty_info, arr_name)
198                     if cleanup is not None:
199                         to_hu_conv += "\n" + cleanup
200                     to_hu_conv_name = conv_name + "_arr"
201                 else:
202                     to_hu_conv = self.consts.primitive_arr_to_hu(ty_info.subty, None, arr_name, arr_name + "_conv")
203                     if to_hu_conv is not None:
204                         to_hu_conv_name = arr_name + "_conv"
205                     else:
206                         to_hu_conv_name = None
207                 from_hu_conv = self.consts.primitive_arr_from_hu(ty_info.subty, None, arr_name)
208                 if subty.from_hu_conv is not None:
209                     hu_conv_b = ""
210                     if subty.from_hu_conv[1] != "":
211                         iterator = self.consts.for_n_in_arr(conv_name, arr_name, subty)
212                         hu_conv_b = iterator[0] + subty.from_hu_conv[1] + ";" + iterator[1]
213                     if from_hu_conv is not None:
214                         arr_conv = self.consts.primitive_arr_from_hu(ty_info.subty, None, self.consts.map_hu_array_elems(arr_name, conv_name, ty_info, subty))
215                         assert arr_conv[1] == ""
216                         from_hu_conv = (arr_conv[0], hu_conv_b)
217                     else:
218                         from_hu_conv = (self.consts.map_hu_array_elems(arr_name, conv_name, ty_info, subty), hu_conv_b)
219
220                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
221                     arg_conv = arg_conv, arg_conv_name = arg_conv_name, arg_conv_cleanup = arg_conv_cleanup,
222                     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)
223         elif ty_info.java_fn_ty_arg == "Ljava/lang/String;":
224             assert not is_nullable
225             if not is_free:
226                 arg_conv = "LDKStr " + ty_info.var_name + "_conv = " + self.consts.str_ref_to_c_call(ty_info.var_name) + ";"
227                 arg_conv_name = ty_info.var_name + "_conv"
228             else:
229                 arg_conv = "LDKStr dummy = { .chars = NULL, .len = 0, .chars_is_owned = false };"
230                 arg_conv_name = "dummy"
231             if ty_info.arr_access is None:
232                 assert False
233                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
234                     arg_conv = arg_conv, arg_conv_name = arg_conv_name, arg_conv_cleanup = None,
235                     ret_conv = ("const char* " + ty_info.var_name + "_str = ",
236                         ";\njstring " + ty_info.var_name + "_conv = " + self.consts.str_ref_to_native_call(ty_info.var_name + "_str", "strlen(" + ty_info.var_name + "_str)") + ";"),
237                     ret_conv_name = ty_info.var_name + "_conv",
238                     to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)
239             else:
240                 free_str = ""
241                 if not holds_ref:
242                     free_str = "\nStr_free(" + ty_info.var_name + "_str);"
243                 to_hu_conv = self.consts.str_to_hu_conv(ty_info.var_name)
244                 to_hu_conv_name = None
245                 if to_hu_conv is not None:
246                     to_hu_conv_name = ty_info.var_name + "_conv"
247                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
248                     arg_conv = arg_conv, arg_conv_name = arg_conv_name, arg_conv_cleanup = None,
249                     ret_conv = ("LDKStr " + ty_info.var_name + "_str = ",
250                         ";\njstring " + ty_info.var_name + "_conv = " + self.consts.str_ref_to_native_call(ty_info.var_name + "_str." + ty_info.arr_access, ty_info.var_name + "_str." + ty_info.arr_len) + ";" + free_str),
251                     ret_conv_name = ty_info.var_name + "_conv",
252                     to_hu_conv=to_hu_conv, to_hu_conv_name=to_hu_conv_name,
253                     from_hu_conv = self.consts.str_from_hu_conv(ty_info.var_name))
254         elif ty_info.var_name == "" and not print_void:
255             # We don't have a parameter name, and want one, just call it arg
256             if not ty_info.is_native_primitive:
257                 assert(not is_free or ty_info.rust_obj not in self.opaque_structs)
258                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
259                     arg_conv = ty_info.rust_obj + " arg_conv = *(" + ty_info.rust_obj + "*)untag_ptr(arg);\nFREE(untag_ptr(arg));",
260                     arg_conv_name = "arg_conv", arg_conv_cleanup = None,
261                     ret_conv = None, ret_conv_name = None, to_hu_conv = "TODO 7", to_hu_conv_name = None, from_hu_conv = None)
262             else:
263                 assert(not is_free)
264                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
265                     arg_conv = None, arg_conv_name = "arg", arg_conv_cleanup = None,
266                     ret_conv = None, ret_conv_name = None, to_hu_conv = "TODO 8", to_hu_conv_name = None, from_hu_conv = None)
267         elif ty_info.is_native_primitive and ty_info.c_ty != "void":
268             assert not is_nullable
269             return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
270                 arg_conv = None, arg_conv_name =  ty_info.var_name, arg_conv_cleanup = None,
271                 ret_conv = (ty_info.c_ty + " " + ty_info.var_name + "_conv = ", ";"), ret_conv_name = ty_info.var_name + "_conv",
272                 to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)
273         elif ty_info.c_ty == "void":
274             assert ty_info.is_native_primitive
275             assert not is_nullable
276             return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
277                 arg_conv = None, arg_conv_name =  ty_info.var_name, arg_conv_cleanup = None,
278                 ret_conv = None, ret_conv_name = ty_info.var_name,
279                 to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)
280         else:
281             if ty_info.var_name == "":
282                 ty_info.var_name = "ret"
283
284             if ty_info.rust_obj in self.opaque_structs:
285                 from_hu_conv = (ty_info.var_name + " == null ? " + self.consts.native_zero_ptr + " : " + self.consts.get_ptr(ty_info.var_name), self.consts.add_ref("this", ty_info.var_name))
286                 opaque_arg_conv = ty_info.rust_obj + " " + ty_info.var_name + "_conv;\n"
287                 opaque_arg_conv = opaque_arg_conv + ty_info.var_name + "_conv.inner = untag_ptr(" + ty_info.var_name + ");\n"
288                 opaque_arg_conv += ty_info.var_name + "_conv.is_owned = ptr_is_owned(" + ty_info.var_name + ");\n"
289                 opaque_arg_conv += "CHECK_INNER_FIELD_ACCESS_OR_NULL(" + ty_info.var_name + "_conv);"
290
291                 if not is_free and (not ty_info.is_ptr or not holds_ref or ty_info.requires_clone == True) and ty_info.requires_clone != False:
292                     if (ty_info.rust_obj.replace("LDK", "") + "_clone") in self.clone_fns:
293                         # 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.
294                         # arg_conv is used when converting a function argument from java normally (with holds_ref set),
295                         # and when converting a java value being returned from a trait method (with holds_ref unset).
296                         # In the second case, we need to clone before returning to C (as once we return the GC can free the object),
297                         # whereas in the first we prefer to clone in C to avoid additional Java code as much as possible.
298                         if holds_ref:
299                             opaque_arg_conv += "\n" + ty_info.var_name + "_conv = " + ty_info.rust_obj.replace("LDK", "") + "_clone(&" + ty_info.var_name + "_conv);"
300                         else:
301                             from_hu_conv = (ty_info.var_name + " == null ? " + self.consts.native_zero_ptr + " : " + ty_info.var_name + ".clone_ptr()", "")
302                     elif ty_info.passed_as_ptr:
303                         opaque_arg_conv += "\n// WARNING: we need a move here but no clone is available for " + ty_info.rust_obj + "\n"
304                         # TODO: Once we support features cloning (which just isn't in C yet), we can make this a compile error instead!
305                         from_hu_conv = (from_hu_conv[0], from_hu_conv[1] + ";\n" +
306                             "// Due to rust's strict-ownership memory model, in some cases we need to \"move\"\n" +
307                             "// an object to pass exclusive ownership to the function being called.\n" +
308                             "// In most cases, we avoid this being visible in GC'd languages by cloning the object\n" +
309                             "// at the FFI layer, creating a new object which Rust can claim ownership of\n" +
310                             "// However, in some cases (eg here), there is no way to clone an object, and thus\n" +
311                             "// we actually have to pass full ownership to Rust.\n" +
312                             "// Thus, after this call, " + ty_info.var_name + " is reset to null and is now a dummy object.\n" + self.consts.set_null_skip_free(ty_info.var_name))
313                 elif not is_free:
314                     opaque_arg_conv += "\n" + ty_info.var_name + "_conv.is_owned = false;"
315
316                 opaque_ret_conv_suf = ";\n"
317                 opaque_ret_conv_suf += self.consts.ptr_c_ty + " " + ty_info.var_name + "_ref = 0;\n"
318                 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
319                     opaque_ret_conv_suf += ty_info.var_name + "_var = " + ty_info.rust_obj.replace("LDK", "") + "_clone(&" + ty_info.var_name + "_var);\n"
320                 elif not holds_ref and ty_info.is_ptr:
321                     opaque_ret_conv_suf += "// WARNING: we may need a move here but no clone is available for " + ty_info.rust_obj + "\n"
322
323                 opaque_ret_conv_suf += "CHECK_INNER_FIELD_ACCESS_OR_NULL(" + ty_info.var_name + "_var);\n"
324                 if holds_ref:
325                     opaque_ret_conv_suf += ty_info.var_name + "_ref = tag_ptr(" + ty_info.var_name + "_var.inner, false);"
326                 else:
327                     opaque_ret_conv_suf += ty_info.var_name + "_ref = tag_ptr(" + ty_info.var_name + "_var.inner, " + ty_info.var_name + "_var.is_owned);"
328
329                 to_hu_conv_sfx = ""
330                 if not ty_info.is_ptr or holds_ref:
331                     to_hu_conv_sfx = "\n" + self.consts.add_ref(ty_info.var_name + "_hu_conv", "this") + ";"
332                 qualified_hu_ty = self.consts.fully_qualified_hu_ty_path(ty_info)
333                 if ty_info.is_ptr:
334                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
335                         arg_conv = opaque_arg_conv, arg_conv_name = "&" + ty_info.var_name + "_conv", arg_conv_cleanup = None,
336                         ret_conv = (ty_info.rust_obj + " " + ty_info.var_name + "_var = *", opaque_ret_conv_suf),
337                         ret_conv_name = ty_info.var_name + "_ref",
338                         to_hu_conv = self.consts.to_hu_conv_templates['ptr'].replace('{human_type}', qualified_hu_ty).replace('{var_name}', ty_info.var_name) + to_hu_conv_sfx,
339                         to_hu_conv_name = ty_info.var_name + "_hu_conv",
340                         from_hu_conv = from_hu_conv)
341                 else:
342                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
343                         arg_conv = opaque_arg_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
344                         ret_conv = (ty_info.rust_obj + " " + ty_info.var_name + "_var = ", opaque_ret_conv_suf),
345                         ret_conv_name = ty_info.var_name + "_ref",
346                         to_hu_conv = self.consts.to_hu_conv_templates['default'].replace('{human_type}', qualified_hu_ty).replace('{var_name}', ty_info.var_name) + to_hu_conv_sfx,
347                         to_hu_conv_name = ty_info.var_name + "_hu_conv",
348                         from_hu_conv = from_hu_conv)
349
350             assert not is_nullable
351             if not ty_info.is_ptr:
352                 if ty_info.rust_obj in self.unitary_enums:
353                     (ret_pfx, ret_sfx) = self.consts.c_unitary_enum_to_native_call(ty_info)
354                     (arg_pfx, arg_sfx) = self.consts.native_unitary_enum_to_c_call(ty_info)
355                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
356                         arg_conv = ty_info.rust_obj + " " + ty_info.var_name + "_conv = " + arg_pfx + ty_info.var_name + arg_sfx + ";",
357                         arg_conv_name = ty_info.var_name + "_conv",
358                         arg_conv_cleanup = None,
359                         ret_conv = (ty_info.c_ty + " " + ty_info.var_name + "_conv = " + ret_pfx, ret_sfx + ";"),
360                         ret_conv_name = ty_info.var_name + "_conv", to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)
361                 base_conv = "void* " + ty_info.var_name + "_ptr = untag_ptr(" + ty_info.var_name + ");\n"
362                 base_conv += "CHECK_ACCESS(" + ty_info.var_name + "_ptr);\n"
363                 base_conv += ty_info.rust_obj + " " + ty_info.var_name + "_conv = *(" + ty_info.rust_obj + "*)(" + ty_info.var_name + "_ptr);"
364                 from_hu_conv = None
365                 if ty_info.rust_obj in self.trait_structs:
366                     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 = ", ";")
367                     if holds_ref:
368                         if (ty_info.rust_obj.replace("LDK", "") + "_clone") in self.clone_fns:
369                             ret_conv = (ret_conv[0] + ty_info.rust_obj.replace("LDK", "") + "_clone(&", ");")
370                         else:
371                             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")
372                             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)"))
373                     if not is_free:
374                         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
375                         if needs_full_clone and (ty_info.rust_obj.replace("LDK", "") + "_clone") in self.clone_fns:
376                             # arg_conv is used when converting a function argument from java normally (with holds_ref set),
377                             # and when converting a java value being returned from a trait method (with holds_ref unset).
378                             # In the second case, we need to clone before returning to C (as once we return the GC can free the object),
379                             # whereas in the first we prefer to clone in C to avoid additional Java code as much as possible.
380                             if holds_ref:
381                                 base_conv += "\n" + ty_info.var_name + "_conv = " + ty_info.rust_obj.replace("LDK", "") + "_clone(&" + ty_info.var_name + "_conv);"
382                             else:
383                                 from_hu_conv = (ty_info.var_name + " == null ? " + self.consts.native_zero_ptr + " : " + ty_info.var_name + ".clone_ptr()", "")
384                                 base_conv += "\n" + "FREE(untag_ptr(" + ty_info.var_name + "));"
385                         else:
386                             base_conv = base_conv + self.consts.trait_struct_inc_refcnt(ty_info)
387                             if needs_full_clone:
388                                 base_conv += "// WARNING: we may need a move here but no clone is available for " + ty_info.rust_obj + "\n"
389                     else:
390                         base_conv = base_conv + "\n" + "FREE(untag_ptr(" + ty_info.var_name + "));"
391                     if from_hu_conv is None:
392                         from_hu_conv = (ty_info.var_name + " == null ? " + self.consts.native_zero_ptr + " : " + self.consts.get_ptr(ty_info.var_name), "")
393                     from_hu_conv = (from_hu_conv[0], self.consts.add_ref("this", ty_info.var_name))
394                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
395                         arg_conv = base_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
396                         ret_conv = ret_conv, ret_conv_name = "tag_ptr(" + ty_info.var_name + "_ret, true)",
397                         to_hu_conv = self.consts.var_decl_statement(ty_info.java_hu_ty, "ret_hu_conv", "new " + ty_info.java_hu_ty + "(null, " + ty_info.var_name + ")") + ";\n" + self.consts.add_ref("ret_hu_conv", "this") + ";",
398                         to_hu_conv_name = "ret_hu_conv", from_hu_conv = from_hu_conv)
399                 needs_full_clone = not is_free and (not ty_info.is_ptr or ty_info.requires_clone == True) and ty_info.requires_clone != False
400                 if needs_full_clone:
401                     if "res" in ty_info.var_name: # XXX: This is a stupid hack
402                         needs_full_clone = False
403                     if needs_full_clone and (ty_info.rust_obj.replace("LDK", "") + "_clone") in self.clone_fns:
404                         # arg_conv is used when converting a function argument from java normally (with holds_ref set),
405                         # and when converting a java value being returned from a trait method (with holds_ref unset).
406                         # In the second case, we need to clone before returning to C (as once we return the GC can free the object),
407                         # whereas in the first we prefer to clone in C to avoid additional Java code as much as possible.
408                         if holds_ref:
409                             base_conv += "\n" + ty_info.var_name + "_conv = " + ty_info.rust_obj.replace("LDK", "") + "_clone((" + ty_info.rust_obj + "*)untag_ptr(" + ty_info.var_name + "));"
410                         else:
411                             from_hu_conv = (ty_info.var_name + " == null ? " + self.consts.native_zero_ptr + " : " + ty_info.var_name + ".clone_ptr()", "")
412                             base_conv += "\n" + "FREE(untag_ptr(" + ty_info.var_name + "));"
413                     elif needs_full_clone:
414                         base_conv = base_conv + "\n// WARNING: we may need a move here but no clone is available for " + ty_info.rust_obj
415                 if not needs_full_clone and ty_info.rust_obj != "LDKu8slice" and (not holds_ref or is_free):
416                     # Don't bother free'ing slices passed in - Rust doesn't auto-free the
417                     # underlying unlike Vecs, and it gives Java more freedom.
418                     base_conv = base_conv + "\nFREE(untag_ptr(" + ty_info.var_name + "));"
419                 if ty_info.rust_obj in self.complex_enums:
420                     to_hu_conv_sfx = ""
421                     if needs_full_clone and (ty_info.rust_obj.replace("LDK", "") + "_clone") not in self.clone_fns:
422                         # We really need a full clone here, but for now we just implement
423                         # a manual clone explicitly for Option<Trait>s
424                         if ty_info.contains_trait:
425                             assert ty_info.rust_obj.startswith("LDKCOption") # We don't support contained traits for anything else yet
426                             optional_ty = ty_info.rust_obj[11:-1]
427                             assert "LDK" + optional_ty in self.trait_structs # We don't support contained traits for anything else yet
428                             to_hu_conv_sfx = self.consts.add_ref("this", ty_info.var_name)
429                             base_conv += "\nif (" + ty_info.var_name + "_conv.tag == " + ty_info.rust_obj + "_Some) {"
430                             base_conv += "\n\t// Manually implement clone for Java trait instances"
431                             optional_ty_info = self.java_c_types("LDK" + optional_ty + " " + ty_info.var_name, None)
432                             base_conv += self.consts.trait_struct_inc_refcnt(optional_ty_info).\
433                                 replace("\n", "\n\t").replace(ty_info.var_name + "_conv", ty_info.var_name + "_conv.some")
434                             base_conv += "\n}"
435                     ret_conv = (self.consts.ptr_c_ty + " " + ty_info.var_name + "_ref = tag_ptr(&", ", false);")
436                     if not holds_ref:
437                         ret_conv = (ty_info.rust_obj + " *" + ty_info.var_name + "_copy = MALLOC(sizeof(" + ty_info.rust_obj + "), \"" + ty_info.rust_obj + "\");\n", "")
438                         ret_conv = (ret_conv[0] + "*" + ty_info.var_name + "_copy = ", "")
439                         ret_conv = (ret_conv[0], ";\n" + self.consts.ptr_c_ty + " " + ty_info.var_name + "_ref = tag_ptr(" + ty_info.var_name + "_copy, true);")
440                     if from_hu_conv is None:
441                         from_hu_conv = (self.consts.get_ptr(ty_info.var_name), "")
442                     from_hu_conv = (from_hu_conv[0], to_hu_conv_sfx)
443                     fully_qualified_ty = self.consts.fully_qualified_hu_ty_path(ty_info)
444                     to_hu_call = fully_qualified_ty + ".constr_from_ptr(" + ty_info.var_name + ")"
445                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
446                         arg_conv = base_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
447                         ret_conv = ret_conv, ret_conv_name = ty_info.var_name + "_ref",
448                         to_hu_conv = self.consts.var_decl_statement(fully_qualified_ty, ty_info.var_name + "_hu_conv", to_hu_call) + ";\n" + self.consts.add_ref(ty_info.var_name + "_hu_conv", "this") + ";",
449                         to_hu_conv_name = ty_info.var_name + "_hu_conv", from_hu_conv = from_hu_conv)
450                 if ty_info.rust_obj in self.result_types:
451                     if holds_ref:
452                         # If we're trying to return a ref, we have to clone.
453                         # We just blindly assume its implemented and let the compiler fail if its not.
454                         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 = ", ";")
455                         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);")
456                     else:
457                         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 = ", ";")
458                     if from_hu_conv is None:
459                         from_hu_conv = (ty_info.var_name + " != null ? " + self.consts.get_ptr(ty_info.var_name) + " : " + self.consts.native_zero_ptr, "")
460                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
461                         arg_conv = base_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
462                         ret_conv = ret_conv, ret_conv_name = "tag_ptr(" + ty_info.var_name + "_conv, true)",
463                         to_hu_conv = self.consts.var_decl_statement(ty_info.java_hu_ty, ty_info.var_name + "_hu_conv", ty_info.java_hu_ty + ".constr_from_ptr(" + ty_info.var_name + ")") + ";",
464                         to_hu_conv_name = ty_info.var_name + "_hu_conv", from_hu_conv = from_hu_conv)
465                 if ty_info.rust_obj in self.tuple_types:
466                     ret_conv_name = "tag_ptr(" + ty_info.var_name + "_conv, "
467                     if holds_ref:
468                         # If we're trying to return a ref, we have to clone.
469                         if (ty_info.rust_obj.replace("LDK", "") + "_clone") not in self.clone_fns:
470                             ret_conv = (ty_info.rust_obj + "* " + ty_info.var_name + "_conv = &", "")
471                             ret_conv = (ret_conv[0], ";\n// WARNING: we really need to clone here, but no clone is available for " + ty_info.rust_obj)
472                             ret_conv_name += "false)"
473                         else:
474                             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 = ", ";")
475                             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);")
476                             ret_conv_name += "true)"
477                     else:
478                         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 = ", ";")
479                         ret_conv_name += "true)"
480                     if not ty_info.is_ptr or holds_ref:
481                         to_hu_conv_sfx = "\n" + self.consts.add_ref(ty_info.var_name + "_hu_conv", "this") + ";"
482                     else:
483                         to_hu_conv_sfx = ""
484                     if from_hu_conv is None:
485                         from_hu_conv = (ty_info.var_name + " != null ? " + self.consts.get_ptr(ty_info.var_name) + " : " + self.consts.native_zero_ptr, "")
486                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
487                         arg_conv = base_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
488                         ret_conv = ret_conv, ret_conv_name = ret_conv_name,
489                         to_hu_conv = self.consts.var_decl_statement(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,
490                         to_hu_conv_name = ty_info.var_name + "_hu_conv", from_hu_conv = from_hu_conv)
491
492                 # The manually-defined types - TxOut, u5, and Error
493                 if ty_info.rust_obj == "LDKError":
494                     assert from_hu_conv is None
495                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
496                         arg_conv = "", arg_conv_name = "(LDKError){ ._dummy = 0 }", arg_conv_cleanup = None,
497                         ret_conv = ("/*", "*/"), ret_conv_name = "0",
498                         to_hu_conv = self.consts.var_decl_statement(ty_info.java_hu_ty, ty_info.var_name + "_conv", "new " + ty_info.java_hu_ty + "(" + ty_info.var_name + ")") + ";",
499                         to_hu_conv_name = ty_info.var_name + "_conv", from_hu_conv = ("0", ""))
500
501                 if ty_info.rust_obj == "LDKu5" or ty_info.rust_obj == "LDKWitnessVersion":
502                     assert from_hu_conv is None
503                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
504                         arg_conv = "", arg_conv_name = "(" + ty_info.rust_obj + "){ ._0 = " + ty_info.var_name + " }", arg_conv_cleanup = None,
505                         ret_conv = ("uint8_t " + ty_info.var_name + "_val = ", "._0;"), ret_conv_name = ty_info.var_name + "_val",
506                         to_hu_conv = self.consts.var_decl_statement(ty_info.java_hu_ty, ty_info.var_name + "_conv", "new " + ty_info.java_hu_ty + "(" + ty_info.var_name + ")") + ";",
507                         to_hu_conv_name = ty_info.var_name + "_conv", from_hu_conv = (ty_info.var_name + ".getVal()", ""))
508
509                 assert ty_info.rust_obj == "LDKTxOut"
510                 if not ty_info.is_ptr and not holds_ref:
511                     ret_conv = ("LDKTxOut* " + ty_info.var_name + "_ref = MALLOC(sizeof(LDKTxOut), \"LDKTxOut\");\n*" + ty_info.var_name + "_ref = ", ";")
512                     ret_conv_name = "tag_ptr(" + ty_info.var_name + "_ref, true)"
513                 else:
514                     ret_conv = ("LDKTxOut* " + ty_info.var_name + "_ref = &", ";")
515                     ret_conv_name = "tag_ptr(" + ty_info.var_name + "_ref, false)"
516                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
517                     arg_conv = base_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
518                     ret_conv = ret_conv, ret_conv_name = ret_conv_name,
519                     to_hu_conv = self.consts.var_decl_statement(ty_info.java_hu_ty, ty_info.var_name + "_conv", "new " +ty_info.java_hu_ty + "(null, " + ty_info.var_name + ")") + ";",
520                     to_hu_conv_name = ty_info.var_name + "_conv", from_hu_conv = (self.consts.get_ptr(ty_info.var_name), ""))
521             elif ty_info.is_ptr:
522                 assert(not is_free)
523                 if ty_info.rust_obj in self.complex_enums:
524                     ret_conv = (self.consts.ptr_c_ty + " ref_" + ty_info.var_name + " = tag_ptr(", ", false); // WARNING: We should clone here!")
525                     from_hu_sfx = self.consts.add_ref("this", ty_info.var_name)
526                     if ty_info.rust_obj.replace("LDK", "") + "_clone" in self.clone_fns:
527                         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"
528                         ret_conv_pfx += "*ret_" + ty_info.var_name + " = " + ty_info.rust_obj.replace("LDK", "") + "_clone("
529                         ret_conv_sfx = ");\n" + self.consts.ptr_c_ty + " ref_" + ty_info.var_name + " = tag_ptr(ret_" + ty_info.var_name + ", true);"
530                         ret_conv = (ret_conv_pfx, ret_conv_sfx)
531                         from_hu_sfx = ""
532                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
533                         arg_conv = ty_info.rust_obj + "* " + ty_info.var_name + "_conv = (" + ty_info.rust_obj + "*)untag_ptr(" + ty_info.var_name + ");",
534                         arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
535                         ret_conv = ret_conv, ret_conv_name = "ref_" + ty_info.var_name,
536                         to_hu_conv = self.consts.var_decl_statement(ty_info.java_hu_ty, ty_info.var_name + "_hu_conv", ty_info.java_hu_ty + ".constr_from_ptr(" + ty_info.var_name + ")") + ";",
537                         to_hu_conv_name = ty_info.var_name + "_hu_conv",
538                         from_hu_conv = (ty_info.var_name + " == null ? " + self.consts.native_zero_ptr + " : " + self.consts.get_ptr(ty_info.var_name), from_hu_sfx))
539                 elif ty_info.rust_obj in self.trait_structs:
540                     if ty_info.nonnull_ptr:
541                         arg_conv = "void* " + ty_info.var_name + "_ptr = untag_ptr(" + ty_info.var_name + ");\n"
542                         arg_conv += "if (ptr_is_owned(" + ty_info.var_name + ")) { CHECK_ACCESS(" + ty_info.var_name + "_ptr); }\n"
543                         arg_conv += ty_info.rust_obj + "* " + ty_info.var_name + "_conv = (" + ty_info.rust_obj + "*)" + ty_info.var_name + "_ptr;"
544                         arg_conv_name = ty_info.var_name + "_conv"
545                     else:
546                         # We map Option<Trait> as *mut Trait, which we can differentiate from &Trait by the NONNULL_PTR annotation.
547                         # We handle the Option<Trait> case here.
548                         arg_conv = ty_info.rust_obj + " *" + ty_info.var_name + "_conv_ptr = NULL;\n"
549                         arg_conv += "if (" + ty_info.var_name + " != 0) {\n"
550                         arg_conv += "\t" + ty_info.rust_obj + " " + ty_info.var_name + "_conv;\n"
551                         arg_conv += "void* " + ty_info.var_name + "_ptr = untag_ptr(" + ty_info.var_name + ");\n"
552                         arg_conv += "CHECK_ACCESS(" + ty_info.var_name + "_ptr);\n"
553                         arg_conv += "\t" + ty_info.var_name + "_conv = *(" + ty_info.rust_obj + "*)" + ty_info.var_name + "_ptr;"
554                         arg_conv += self.consts.trait_struct_inc_refcnt(ty_info).replace("\n", "\n\t")
555                         arg_conv += "\n\t" + ty_info.var_name + "_conv_ptr = MALLOC(sizeof(" + ty_info.rust_obj + "), \"" + ty_info.rust_obj + "\");\n"
556                         arg_conv += "\t*" + ty_info.var_name + "_conv_ptr = " + ty_info.var_name + "_conv;\n"
557                         arg_conv += "}"
558                         arg_conv_name = ty_info.var_name + "_conv_ptr"
559                     if ty_info.rust_obj.replace("LDK", "") + "_clone" in self.clone_fns:
560                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
561                             arg_conv = arg_conv, arg_conv_name = arg_conv_name, arg_conv_cleanup = None,
562                             ret_conv = (ty_info.rust_obj + " *" + ty_info.var_name + "_clone = MALLOC(sizeof(" + ty_info.rust_obj + "), \"" + ty_info.rust_obj + "\");\n" +
563                                 "*" + ty_info.var_name + "_clone = " + ty_info.rust_obj.replace("LDK", "") + "_clone(", ");"),
564                             ret_conv_name = "tag_ptr(" + ty_info.var_name + "_clone, true)",
565                             to_hu_conv = self.consts.var_decl_statement(ty_info.java_hu_ty, "ret_hu_conv", "new " + ty_info.java_hu_ty + "(null, " + ty_info.var_name + ")") + ";\n" + self.consts.add_ref("ret_hu_conv", "this") + ";",
566                             to_hu_conv_name = "ret_hu_conv",
567                             from_hu_conv = (ty_info.var_name + " == null ? " + self.consts.native_zero_ptr + " : " + self.consts.get_ptr(ty_info.var_name), ""))
568                     else:
569                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
570                             arg_conv = arg_conv, arg_conv_name = arg_conv_name, arg_conv_cleanup = None,
571                             ret_conv = ("// WARNING: This object doesn't live past this scope, needs clone!\n" + self.consts.ptr_c_ty + " ret_" + ty_info.var_name + " = tag_ptr(", ", false);"),
572                             ret_conv_name = "ret_" + ty_info.var_name,
573                             to_hu_conv = self.consts.var_decl_statement(ty_info.java_hu_ty, "ret_hu_conv", "new " + ty_info.java_hu_ty + "(null, " + ty_info.var_name + ")") + ";\n" + self.consts.add_ref("ret_hu_conv", "this") + ";",
574                             to_hu_conv_name = "ret_hu_conv",
575                             from_hu_conv = (ty_info.var_name + " == null ? " + self.consts.native_zero_ptr + " : " + self.consts.get_ptr(ty_info.var_name), self.consts.add_ref("this", ty_info.var_name)))
576                 ret_conv = (self.consts.ptr_c_ty + " ret_" + ty_info.var_name + " = tag_ptr(", ", true);")
577                 if holds_ref:
578                     ret_conv = (ret_conv[0], ", false);")
579                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
580                     arg_conv = ty_info.rust_obj + "* " + ty_info.var_name + "_conv = (" + ty_info.rust_obj + "*)untag_ptr(" + ty_info.var_name + ");",
581                     arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
582                     ret_conv = ret_conv, ret_conv_name = "ret_" + ty_info.var_name,
583                     to_hu_conv = "TODO 3", to_hu_conv_name = None, from_hu_conv = None) # its a pointer, no conv needed
584             assert False # We should have handled every case by now.