_ Git - ldk-java/blob - csharp_strings.py

   1 from bindingstypes import *
   2 from enum import Enum
   3 import sys
   4
   5 class Target(Enum):
   6     CSHARP = 1,
   7
   8 class Consts:
   9     def __init__(self, DEBUG: bool, target: Target, **kwargs):
  10         self.target = target
  11         self.c_array_class_caches = set()
  12         self.c_type_map = dict(
  13             bool = ['bool'],
  14             uint8_t = ['byte'],
  15             uint16_t = ['short'],
  16             uint32_t = ['int'],
  17             uint64_t = ['long'],
  18             int64_t = ['long'],
  19         )
  20         self.java_type_map = dict(
  21             String = "string"
  22         )
  23         self.java_hu_type_map = dict(
  24             String = "string"
  25         )
  26
  27         self.to_hu_conv_templates = dict(
  28             ptr = '{human_type} {var_name}_hu_conv = null; if ({var_name} < 0 || {var_name} > 4096) { {var_name}_hu_conv = new {human_type}(null, {var_name}); }',
  29             default = '{human_type} {var_name}_hu_conv = null; if ({var_name} < 0 || {var_name} > 4096) { {var_name}_hu_conv = new {human_type}(null, {var_name}); }'
  30         )
  31
  32         self.bindings_header = """
  33 using org.ldk.enums;
  34 using org.ldk.impl;
  35 using System.Runtime.InteropServices;
  36
  37 namespace org { namespace ldk { namespace impl {
  38
  39 internal class bindings {
  40         /*static {
  41                 init(java.lang.Enum.class, VecOrSliceDef.class);
  42                 init_class_cache();
  43                 if (!get_lib_version_string().equals(version.get_ldk_java_bindings_version()))
  44                         throw new ArgumentException("Compiled LDK library and LDK class failes do not match");
  45                 // Fetching the LDK versions from C also checks that the header and binaries match
  46                 Console.Error.WriteLine("Loaded LDK-Java Bindings " + version.get_ldk_java_bindings_version() + " with LDK " + get_ldk_version() + " and LDK-C-Bindings " + get_ldk_c_bindings_version());
  47         }*/
  48         //static extern void init(java.lang.Class c);
  49         //static native void init_class_cache();
  50 """
  51         self.bindings_header += self.native_meth_decl("get_lib_version_string", "string") + "();\n"
  52         self.bindings_header += self.native_meth_decl("get_ldk_c_bindings_version", "string") + "();\n"
  53         self.bindings_header += self.native_meth_decl("get_ldk_version", "string") + "();\n\n"
  54
  55         self.bindings_version_file = """
  56
  57 public class version {
  58         public static string get_ldk_java_bindings_version() {
  59                 return "<git_version_ldk_garbagecollected>";
  60         }
  61 }"""
  62
  63         self.util_fn_pfx = """using org.ldk.impl;
  64 using org.ldk.enums;
  65 using org.ldk.util;
  66 using org.ldk.structs;
  67 using System;
  68
  69 namespace org { namespace ldk { namespace util {
  70 public class UtilMethods {
  71 """
  72         self.util_fn_sfx = "} } } }"
  73         self.common_base = """using System.Collections.Generic;
  74 using System.Diagnostics;
  75
  76 public class CommonBase {
  77         protected internal long ptr;
  78         protected internal LinkedList<object> ptrs_to = new LinkedList<object>();
  79         protected CommonBase(long ptr) { Trace.Assert(ptr < 0 || ptr > 4096); this.ptr = ptr; }
  80 }
  81 """
  82
  83         self.txin_defn = """public class TxIn : CommonBase {
  84         /** The witness in this input, in serialized form */
  85         public readonly byte[] witness;
  86         /** The script_sig in this input */
  87         public readonly byte[] script_sig;
  88         /** The transaction output's sequence number */
  89         public readonly int sequence;
  90         /** The txid this input is spending */
  91         public readonly byte[] previous_txid;
  92         /** The output index within the spent transaction of the output this input is spending */
  93         public readonly int previous_vout;
  94
  95         internal TxIn(object _dummy, long ptr) : base(ptr) {
  96                 this.witness = bindings.TxIn_get_witness(ptr);
  97                 this.script_sig = bindings.TxIn_get_script_sig(ptr);
  98                 this.sequence = bindings.TxIn_get_sequence(ptr);
  99                 this.previous_txid = bindings.TxIn_get_previous_txid(ptr);
 100                 this.previous_vout = bindings.TxIn_get_previous_vout(ptr);
 101         }
 102         public TxIn(byte[] witness, byte[] script_sig, int sequence, byte[] previous_txid, int previous_vout)
 103         : this(null, bindings.TxIn_new(witness, script_sig, sequence, previous_txid, previous_vout)) {}
 104
 105         ~TxIn() {
 106                 if (ptr != 0) { bindings.TxIn_free(ptr); }
 107         }
 108 }"""
 109
 110         self.txout_defn = """public class TxOut : CommonBase {
 111         /** The script_pubkey in this output */
 112         public readonly byte[] script_pubkey;
 113         /** The value, in satoshis, of this output */
 114         public readonly long value;
 115
 116     internal TxOut(object _dummy, long ptr) : base(ptr) {
 117                 this.script_pubkey = bindings.TxOut_get_script_pubkey(ptr);
 118                 this.value = bindings.TxOut_get_value(ptr);
 119         }
 120     public TxOut(long value, byte[] script_pubkey) : this(null, bindings.TxOut_new(script_pubkey, value)) {}
 121
 122         ~TxOut() {
 123                 if (ptr != 0) { bindings.TxOut_free(ptr); }
 124         }
 125 }"""
 126
 127         self.scalar_defn = """public class BigEndianScalar : CommonBase {
 128         /** The bytes of the scalar value, in big endian */
 129         public readonly byte[] scalar_bytes;
 130
 131     internal BigEndianScalar(object _dummy, long ptr) : base(ptr) {
 132                 this.scalar_bytes = bindings.BigEndianScalar_get_bytes(ptr);
 133         }
 134     public BigEndianScalar(byte[] scalar_bytes) : base(bindings.BigEndianScalar_new(scalar_bytes)) {
 135                 this.scalar_bytes = bindings.BigEndianScalar_get_bytes(ptr);
 136         }
 137
 138         ~BigEndianScalar() {
 139                 if (ptr != 0) { bindings.BigEndianScalar_free(ptr); }
 140         }
 141 }"""
 142
 143
 144         self.c_file_pfx = """
 145 // On OSX jlong (ie long long) is not equivalent to int64_t, so we override here
 146 #define int64_t jlong
 147 #include <lightning.h>
 148 #include <string.h>
 149 #include <stdatomic.h>
 150 #include <stdlib.h>
 151
 152 #define LIKELY(v) __builtin_expect(!!(v), 1)
 153 #define UNLIKELY(v) __builtin_expect(!!(v), 0)
 154
 155 """
 156
 157         self.c_file_pfx = self.c_file_pfx + "#include <stdio.h>\n#define DEBUG_PRINT(...) fprintf(stderr, __VA_ARGS__)\n"
 158
 159         if not DEBUG or sys.platform == "darwin":
 160             self.c_file_pfx = self.c_file_pfx + """#define do_MALLOC(a, _b, _c) malloc(a)
 161 #define MALLOC(a, _) malloc(a)
 162 #define FREE(p) if ((uint64_t)(p) > 4096) { free(p); }
 163 #define CHECK_ACCESS(p)
 164 #define CHECK_INNER_FIELD_ACCESS_OR_NULL(v)
 165 """
 166         if not DEBUG:
 167             self.c_file_pfx += """#define DO_ASSERT(a) (void)(a)
 168 #define CHECK(a)
 169 """
 170         if DEBUG:
 171             self.c_file_pfx = self.c_file_pfx + """#include <assert.h>
 172 // Always run a, then assert it is true:
 173 #define DO_ASSERT(a) do { bool _assert_val = (a); assert(_assert_val); } while(0)
 174 // Assert a is true or do nothing
 175 #define CHECK(a) DO_ASSERT(a)
 176
 177 void __attribute__((constructor)) debug_log_version() {
 178         if (check_get_ldk_version() == NULL)
 179                 DEBUG_PRINT("LDK version did not match the header we built against\\n");
 180         if (check_get_ldk_bindings_version() == NULL)
 181                 DEBUG_PRINT("LDK C Bindings version did not match the header we built against\\n");
 182 }
 183 """
 184
 185             if sys.platform != "darwin":
 186                 self.c_file_pfx += """
 187 // Running a leak check across all the allocations and frees of the JDK is a mess,
 188 // so instead we implement our own naive leak checker here, relying on the -wrap
 189 // linker option to wrap malloc/calloc/realloc/free, tracking everyhing allocated
 190 // and free'd in Rust or C across the generated bindings shared library.
 191 #include <threads.h>
 192 """
 193
 194                 self.c_file_pfx = self.c_file_pfx + "#include <execinfo.h>\n"
 195                 self.c_file_pfx = self.c_file_pfx + """
 196 #include <unistd.h>
 197 #include <pthread.h>
 198 static pthread_mutex_t allocation_mtx;
 199
 200 void __attribute__((constructor)) init_mtx() {
 201         DO_ASSERT(!pthread_mutex_init(&allocation_mtx, NULL));
 202 }
 203
 204 #define BT_MAX 128
 205 typedef struct allocation {
 206         struct allocation* next;
 207         void* ptr;
 208         const char* struct_name;
 209         void* bt[BT_MAX];
 210         int bt_len;
 211         unsigned long alloc_len;
 212 } allocation;
 213 static allocation* allocation_ll = NULL;
 214
 215 void* __real_malloc(size_t len);
 216 void* __real_calloc(size_t nmemb, size_t len);
 217 static void new_allocation(void* res, const char* struct_name, size_t len) {
 218         allocation* new_alloc = __real_malloc(sizeof(allocation));
 219         new_alloc->ptr = res;
 220         new_alloc->struct_name = struct_name;
 221         new_alloc->bt_len = backtrace(new_alloc->bt, BT_MAX);
 222         new_alloc->alloc_len = len;
 223         DO_ASSERT(!pthread_mutex_lock(&allocation_mtx));
 224         new_alloc->next = allocation_ll;
 225         allocation_ll = new_alloc;
 226         DO_ASSERT(!pthread_mutex_unlock(&allocation_mtx));
 227 }
 228 static void* do_MALLOC(size_t len, const char* struct_name, int lineno) {
 229         void* res = __real_malloc(len);
 230         new_allocation(res, struct_name, lineno);
 231         return res;
 232 }
 233 #define MALLOC(len, struct_name) do_MALLOC(len, struct_name, __LINE__)
 234
 235 void __real_free(void* ptr);
 236 static void alloc_freed(void* ptr) {
 237         allocation* p = NULL;
 238         DO_ASSERT(!pthread_mutex_lock(&allocation_mtx));
 239         allocation* it = allocation_ll;
 240         while (it->ptr != ptr) {
 241                 p = it; it = it->next;
 242                 if (it == NULL) {
 243                         DEBUG_PRINT("ERROR: Tried to free unknown pointer %p at:\\n", ptr);
 244                         void* bt[BT_MAX];
 245                         int bt_len = backtrace(bt, BT_MAX);
 246                         backtrace_symbols_fd(bt, bt_len, STDERR_FILENO);
 247                         DEBUG_PRINT("\\n\\n");
 248                         DO_ASSERT(!pthread_mutex_unlock(&allocation_mtx));
 249                         return; // addrsan should catch malloc-unknown and print more info than we have
 250                 }
 251         }
 252         if (p) { p->next = it->next; } else { allocation_ll = it->next; }
 253         DO_ASSERT(!pthread_mutex_unlock(&allocation_mtx));
 254         DO_ASSERT(it->ptr == ptr);
 255         __real_free(it);
 256 }
 257 static void FREE(void* ptr) {
 258         if ((uint64_t)ptr <= 4096) return; // Rust loves to create pointers to the NULL page for dummys
 259         alloc_freed(ptr);
 260         __real_free(ptr);
 261 }
 262
 263 void* __wrap_malloc(size_t len) {
 264         void* res = __real_malloc(len);
 265         new_allocation(res, "malloc call", len);
 266         return res;
 267 }
 268 void* __wrap_calloc(size_t nmemb, size_t len) {
 269         void* res = __real_calloc(nmemb, len);
 270         new_allocation(res, "calloc call", len);
 271         return res;
 272 }
 273 void __wrap_free(void* ptr) {
 274         if (ptr == NULL) return;
 275         alloc_freed(ptr);
 276         __real_free(ptr);
 277 }
 278
 279 static void CHECK_ACCESS(const void* ptr) {
 280         DO_ASSERT(!pthread_mutex_lock(&allocation_mtx));
 281         allocation* it = allocation_ll;
 282         while (it->ptr != ptr) {
 283                 it = it->next;
 284                 if (it == NULL) {
 285                         DEBUG_PRINT("ERROR: Tried to access unknown pointer %p at:\\n", ptr);
 286                         void* bt[BT_MAX];
 287                         int bt_len = backtrace(bt, BT_MAX);
 288                         backtrace_symbols_fd(bt, bt_len, STDERR_FILENO);
 289                         DEBUG_PRINT("\\n\\n");
 290                         DO_ASSERT(!pthread_mutex_unlock(&allocation_mtx));
 291                         return; // addrsan should catch and print more info than we have
 292                 }
 293         }
 294         DO_ASSERT(!pthread_mutex_unlock(&allocation_mtx));
 295 }
 296 #define CHECK_INNER_FIELD_ACCESS_OR_NULL(v) \\
 297         if (v.is_owned && v.inner != NULL) { \\
 298                 const void *p = __unmangle_inner_ptr(v.inner); \\
 299                 if (p != NULL) { \\
 300                         CHECK_ACCESS(p); \\
 301                 } \\
 302         }
 303
 304 void* __real_realloc(void* ptr, size_t newlen);
 305 void* __wrap_realloc(void* ptr, size_t len) {
 306         if (ptr != NULL) alloc_freed(ptr);
 307         void* res = __real_realloc(ptr, len);
 308         new_allocation(res, "realloc call", len);
 309         return res;
 310 }
 311 void __wrap_reallocarray(void* ptr, size_t new_sz) {
 312         // Rust doesn't seem to use reallocarray currently
 313         DO_ASSERT(false);
 314 }
 315
 316 void __attribute__((destructor)) check_leaks() {
 317         unsigned long alloc_count = 0;
 318         unsigned long alloc_size = 0;
 319         DEBUG_PRINT("The following LDK-allocated blocks still remain.\\n");
 320         DEBUG_PRINT("Note that this is only accurate if System.gc(); System.runFinalization()\\n");
 321         DEBUG_PRINT("was called prior to exit after all LDK objects were out of scope.\\n");
 322         for (allocation* a = allocation_ll; a != NULL; a = a->next) {
 323                 DEBUG_PRINT("%s %p (%lu bytes) remains:\\n", a->struct_name, a->ptr, a->alloc_len);
 324                 backtrace_symbols_fd(a->bt, a->bt_len, STDERR_FILENO);
 325                 DEBUG_PRINT("\\n\\n");
 326                 alloc_count++;
 327                 alloc_size += a->alloc_len;
 328         }
 329         DEBUG_PRINT("%lu allocations remained for %lu bytes.\\n", alloc_count, alloc_size);
 330         DEBUG_PRINT("Note that this is only accurate if System.gc(); System.runFinalization()\\n");
 331         DEBUG_PRINT("was called prior to exit after all LDK objects were out of scope.\\n");
 332 }
 333 """
 334         self.c_file_pfx = self.c_file_pfx + """
 335
 336 // We assume that CVec_u8Z and u8slice are the same size and layout (and thus pointers to the two can be mixed)
 337 _Static_assert(sizeof(LDKCVec_u8Z) == sizeof(LDKu8slice), "Vec<u8> and [u8] need to have been mapped identically");
 338 _Static_assert(offsetof(LDKCVec_u8Z, data) == offsetof(LDKu8slice, data), "Vec<u8> and [u8] need to have been mapped identically");
 339 _Static_assert(offsetof(LDKCVec_u8Z, datalen) == offsetof(LDKu8slice, datalen), "Vec<u8> and [u8] need to have been mapped identically");
 340
 341 _Static_assert(sizeof(void*) <= 8, "Pointers must fit into 64 bits");
 342
 343 #define DECL_ARR_TYPE(ty, name) \\
 344         struct name##array { \\
 345                 uint64_t arr_len; /* uint32_t would suffice but we want to align uint64_ts as well */ \\
 346                 ty elems[]; \\
 347         }; \\
 348         typedef struct name##array * name##Array; \\
 349         static inline name##Array init_##name##Array(size_t arr_len, int lineno) { \\
 350                 name##Array arr = (name##Array)do_MALLOC(arr_len * sizeof(ty) + sizeof(uint64_t), #name" array init", lineno); \\
 351                 arr->arr_len = arr_len; \\
 352                 return arr; \\
 353         }
 354
 355 DECL_ARR_TYPE(int64_t, int64_t);
 356 DECL_ARR_TYPE(uint64_t, uint64_t);
 357 DECL_ARR_TYPE(int8_t, int8_t);
 358 DECL_ARR_TYPE(int16_t, int16_t);
 359 DECL_ARR_TYPE(uint32_t, uint32_t);
 360 DECL_ARR_TYPE(void*, ptr);
 361 DECL_ARR_TYPE(char, char);
 362 typedef charArray jstring;
 363
 364 static inline jstring str_ref_to_cs(const char* chars, size_t len) {
 365         charArray arr = init_charArray(len, __LINE__);
 366         memcpy(arr->elems, chars, len);
 367         return arr;
 368 }
 369 static inline LDKStr str_ref_to_owned_c(const jstring str) {
 370         char* newchars = MALLOC(str->arr_len + 1, "String chars");
 371         memcpy(newchars, str->elems, str->arr_len);
 372         newchars[str->arr_len] = 0;
 373         LDKStr res = {
 374                 .chars = newchars,
 375                 .len = str->arr_len,
 376                 .chars_is_owned = true
 377         };
 378         return res;
 379 }
 380
 381 jstring CS_LDK_get_ldk_c_bindings_version() {
 382         return str_ref_to_cs(check_get_ldk_bindings_version(), strlen(check_get_ldk_bindings_version()));
 383 }
 384 jstring CS_LDK_get_ldk_version() {
 385         return str_ref_to_cs(check_get_ldk_version(), strlen(check_get_ldk_version()));
 386 }
 387 #include "version.c"
 388 """
 389         self.c_version_file = """const char* CS_LDK_get_lib_version_string() {
 390         return "<git_version_ldk_garbagecollected>";
 391 }"""
 392
 393         self.hu_struct_file_prefix = """using org.ldk.impl;
 394 using org.ldk.enums;
 395 using org.ldk.util;
 396 using System;
 397
 398 namespace org { namespace ldk { namespace structs {
 399
 400 """
 401         self.hu_struct_file_suffix = "} } }\n"
 402         self.c_fn_args_pfx = ""
 403         self.c_fn_ty_pfx = ""
 404         self.file_ext = ".cs"
 405         self.ptr_c_ty = "int64_t"
 406         self.ptr_native_ty = "long"
 407         self.u128_native_ty = "UInt128"
 408         self.usize_c_ty = "int64_t"
 409         self.usize_native_ty = "long"
 410         self.native_zero_ptr = "0"
 411         self.result_c_ty = "jclass"
 412         self.ptr_arr = "jobjectArray"
 413         self.is_arr_some_check = ("", " != NULL")
 414         self.get_native_arr_len_call = ("(*env)->GetArrayLength(env, ", ")")
 415
 416         self.bindings_footer_wip = "\tstatic bindings() {\n"
 417     def bindings_footer(self):
 418         return self.bindings_footer_wip + "\t}\n}\n} } }\n"
 419
 420     def native_meth_decl(self, meth_name, ret_ty_str):
 421         return "\t[DllImport (\"ldkcsharp\", EntryPoint=\"CS_LDK_" + meth_name + "\")] public static extern " + ret_ty_str + " " + meth_name
 422
 423     def c_fn_name_define_pfx(self, fn_name, have_args):
 424         return " CS_LDK_" + fn_name + "("
 425
 426     def construct_jenv(self):
 427         res =  "JNIEnv *env;\n"
 428         res += "jint get_jenv_res = (*j_calls->vm)->GetEnv(j_calls->vm, (void**)&env, JNI_VERSION_1_6);\n"
 429         res += "if (get_jenv_res == JNI_EDETACHED) {\n"
 430         res += "\tDO_ASSERT((*j_calls->vm)->AttachCurrentThread(j_calls->vm, (void**)&env, NULL) == JNI_OK);\n"
 431         res += "} else {\n"
 432         res += "\tDO_ASSERT(get_jenv_res == JNI_OK);\n"
 433         res += "}\n"
 434         return res
 435     def deconstruct_jenv(self):
 436         res = "if (get_jenv_res == JNI_EDETACHED) {\n"
 437         res += "\tDO_ASSERT((*j_calls->vm)->DetachCurrentThread(j_calls->vm) == JNI_OK);\n"
 438         res += "}\n"
 439         return res
 440
 441     def release_native_arr_ptr_call(self, ty_info, arr_var, arr_ptr_var):
 442         return None
 443     def create_native_arr_call(self, arr_len, ty_info):
 444         if ty_info.c_ty == "ptrArray":
 445             assert ty_info.rust_obj == "LDKCVec_U5Z" or (ty_info.subty is not None and (ty_info.subty.c_ty.endswith("Array") or ty_info.subty.rust_obj == "LDKStr"))
 446         return "init_" + ty_info.c_ty + "(" + arr_len + ", __LINE__)"
 447     def set_native_arr_contents(self, arr_name, arr_len, ty_info):
 448         if ty_info.c_ty == "int8_tArray":
 449             return ("memcpy(" + arr_name + "->elems, ", ", " + arr_len + ")")
 450         elif ty_info.c_ty == "int16_tArray":
 451             return ("memcpy(" + arr_name + "->elems, ", ", " + arr_len + " * 2)")
 452         else:
 453             assert False
 454     def get_native_arr_contents(self, arr_name, dest_name, arr_len, ty_info, copy):
 455         if ty_info.c_ty == "int8_tArray" or ty_info.c_ty == "int16_tArray":
 456             if copy:
 457                 byte_len = arr_len
 458                 if ty_info.c_ty == "int16_tArray":
 459                     byte_len = arr_len + " * 2"
 460                 return "memcpy(" + dest_name + ", " + arr_name + "->elems, " + byte_len + "); FREE(" + arr_name + ")"
 461         assert not copy
 462         if ty_info.c_ty == "ptrArray":
 463             return "(void*) " + arr_name + "->elems"
 464         else:
 465             return arr_name + "->elems"
 466     def get_native_arr_elem(self, arr_name, idxc, ty_info):
 467         assert False # Only called if above is None
 468     def get_native_arr_ptr_call(self, ty_info):
 469         if ty_info.subty is not None:
 470             return "(" + ty_info.subty.c_ty + "*)(((uint8_t*)", ") + 8)"
 471         return "(" + ty_info.c_ty + "*)(((uint8_t*)", ") + 8)"
 472     def get_native_arr_entry_call(self, ty_info, arr_name, idxc, entry_access):
 473         return None
 474     def cleanup_native_arr_ref_contents(self, arr_name, dest_name, arr_len, ty_info):
 475         if ty_info.c_ty == "int8_tArray":
 476             return "FREE(" + arr_name + ");"
 477         else:
 478             return "FREE(" + arr_name + ")"
 479
 480     def map_hu_array_elems(self, arr_name, conv_name, arr_ty, elem_ty):
 481         if elem_ty.java_hu_ty == "UInt5":
 482             return arr_name + " != null ? InternalUtils.convUInt5Array(" + arr_name + ") : null"
 483         elif elem_ty.java_hu_ty == "WitnessVersion":
 484             return arr_name + " != null ? InternalUtils.convWitnessVersionArray(" + arr_name + ") : null"
 485         else:
 486             return arr_name + " != null ? InternalUtils.mapArray(" + arr_name + ", " + conv_name + " => " + elem_ty.from_hu_conv[0] + ") : null"
 487
 488     def str_ref_to_native_call(self, var_name, str_len):
 489         return "str_ref_to_cs(" + var_name + ", " + str_len + ")"
 490     def str_ref_to_c_call(self, var_name):
 491         return "str_ref_to_owned_c(" + var_name + ")"
 492     def str_to_hu_conv(self, var_name):
 493         return None
 494     def str_from_hu_conv(self, var_name):
 495         return None
 496
 497     def init_str(self):
 498         return ""
 499
 500     def var_decl_statement(self, ty_string, var_name, statement):
 501         return ty_string + " " + var_name + " = " + statement
 502
 503     def get_java_arr_len(self, arr_name):
 504         return arr_name + ".Length"
 505     def get_java_arr_elem(self, elem_ty, arr_name, idx):
 506         return arr_name + "[" + idx + "]"
 507     def constr_hu_array(self, ty_info, arr_len):
 508         base_ty = ty_info.subty.java_hu_ty.split("[")[0].split("<")[0]
 509         conv = "new " + base_ty + "[" + arr_len + "]"
 510         if "[" in ty_info.subty.java_hu_ty.split("<")[0]:
 511             # Do a bit of a dance to move any excess [] to the end
 512             conv += "[" + ty_info.subty.java_hu_ty.split("<")[0].split("[")[1]
 513         return conv
 514     def cleanup_converted_native_array(self, ty_info, arr_name):
 515         return None
 516
 517     def primitive_arr_from_hu(self, arr_ty, fixed_len, arr_name):
 518         mapped_ty = arr_ty.subty
 519         if arr_ty.rust_obj == "LDKU128":
 520             return ("" + arr_name + ".getLEBytes()", "")
 521         if fixed_len is not None:
 522             return ("InternalUtils.check_arr_len(" + arr_name + ", " + fixed_len + ")", "")
 523         return None
 524     def primitive_arr_to_hu(self, arr_ty, fixed_len, arr_name, conv_name):
 525         if arr_ty.rust_obj == "LDKU128":
 526             return "org.ldk.util.UInt128 " + conv_name + " = new org.ldk.util.UInt128(" + arr_name + ");"
 527         return None
 528
 529     def java_arr_ty_str(self, elem_ty_str):
 530         return elem_ty_str + "[]"
 531
 532     def for_n_in_range(self, n, minimum, maximum):
 533         return "for (int " + n + " = " + minimum + "; " + n + " < " + maximum + "; " + n + "++) {"
 534     def for_n_in_arr(self, n, arr_name, arr_elem_ty):
 535         return ("foreach (" + arr_elem_ty.java_hu_ty + " " + n + " in " + arr_name + ") { ", " }")
 536
 537     def get_ptr(self, var):
 538         return var + ".ptr"
 539     def set_null_skip_free(self, var):
 540         return var + ".ptr" + " = 0;"
 541
 542     def add_ref(self, holder, referent):
 543         return "if (" + holder + " != null) { " + holder + ".ptrs_to.AddLast(" + referent + "); }"
 544
 545     def fully_qualified_hu_ty_path(self, ty):
 546         if ty.java_fn_ty_arg.startswith("L") and ty.java_fn_ty_arg.endswith(";"):
 547             return ty.java_hu_ty
 548         if ty.java_hu_ty == "UnqualifiedError" or ty.java_hu_ty == "UInt128" or ty.java_hu_ty == "UInt5" or ty.java_hu_ty == "WitnessVersion":
 549             return "org.ldk.util." + ty.java_hu_ty
 550         if not ty.is_native_primitive and ty.rust_obj is not None and not "[]" in ty.java_hu_ty:
 551             return "org.ldk.structs." + ty.java_hu_ty
 552         return ty.java_hu_ty
 553
 554     def native_c_unitary_enum_map(self, struct_name, variants, enum_doc_comment):
 555         out_java_enum = "namespace org { namespace ldk { namespace enums {"
 556         out_java = ""
 557         out_c = ""
 558
 559         out_c = "static inline LDK" + struct_name + " LDK" + struct_name + "_from_cs(int32_t ord) {\n"
 560         out_c += "\tswitch (ord) {\n"
 561
 562         if enum_doc_comment is not None:
 563             out_java_enum += "/**\n * " + enum_doc_comment.replace("\n", "\n * ") + "\n */\n"
 564         out_java_enum += "public enum " + struct_name + " {\n"
 565         ord_v = 0
 566         for var, var_docs in variants:
 567             if var_docs is not None:
 568                 out_java_enum += "\t/**\n\t * " + var_docs.replace("\n", "\n\t * ") + "\n\t */\n"
 569             out_java_enum += "\t" + var + ",\n"
 570             out_c = out_c + "\t\tcase %d: return %s;\n" % (ord_v, var)
 571             ord_v = ord_v + 1
 572         out_java_enum += "}"
 573         out_c += "\t\tdefault: abort();\n"
 574         out_c += "\t}\n"
 575         out_c += "}\n"
 576
 577         out_c = out_c + "static inline int32_t LDK" + struct_name + "_to_cs(LDK" + struct_name + " val) {\n"
 578         out_c = out_c + "\tswitch (val) {\n"
 579         ord_v = 0
 580         for var, _ in variants:
 581             out_c = out_c + "\t\tcase " + var + ": return %d;\n" % ord_v
 582             ord_v = ord_v + 1
 583         out_c = out_c + "\t\tdefault: abort();\n"
 584         out_c = out_c + "\t}\n"
 585         out_c = out_c + "}\n"
 586
 587         return (out_c, out_java_enum + "} } }\n", out_java)
 588
 589     def c_unitary_enum_to_native_call(self, ty_info):
 590         return (ty_info.rust_obj + "_to_cs(", ")")
 591     def native_unitary_enum_to_c_call(self, ty_info):
 592         return (ty_info.rust_obj + "_from_cs(", ")")
 593
 594     def c_complex_enum_pfx(self, struct_name, variants, init_meth_jty_strs):
 595         out_c = ""
 596         for var in variants:
 597             out_c = out_c + "static jclass " + struct_name + "_" + var + "_class = NULL;\n"
 598             out_c = out_c + "static jmethodID " + struct_name + "_" + var + "_meth = NULL;\n"
 599         out_c += "void" + self.c_fn_name_define_pfx(struct_name.replace("_", "_1") + "_init", True) + self.c_fn_args_pfx + ") {\n"
 600         for var_name in variants:
 601             out_c += "\t" + struct_name + "_" + var_name + "_class =\n"
 602             out_c += "\t\t(*env)->NewGlobalRef(env, (*env)->FindClass(env, \"org/ldk/impl/bindings$" + struct_name + "$" + var_name + "\"));\n"
 603             out_c += "\tCHECK(" + struct_name + "_" + var_name + "_class != NULL);\n"
 604             out_c += "\t" + struct_name + "_" + var_name + "_meth = (*env)->GetMethodID(env, " + struct_name + "_" + var_name + "_class, \"<init>\", \"(" + init_meth_jty_strs[var_name] + ")V\");\n"
 605             out_c += "\tCHECK(" + struct_name + "_" + var_name + "_meth != NULL);\n"
 606         out_c = out_c + "}\n"
 607         return out_c
 608
 609     def c_complex_enum_pass_ty(self, struct_name):
 610         return "jobject"
 611
 612     def c_constr_native_complex_enum(self, struct_name, variant, c_params):
 613         ret = "(*env)->NewObject(env, " + struct_name + "_" + variant + "_class, " + struct_name + "_" + variant + "_meth"
 614         for param in c_params:
 615             ret = ret + ", " + param
 616         return ret + ")"
 617
 618     def native_c_map_trait(self, struct_name, field_vars, flattened_field_vars, field_fns, trait_doc_comment):
 619         out_java_trait = ""
 620         out_java = ""
 621
 622         # First generate most of the Java code, note that we need information about java method argument strings for C
 623         out_java_trait += self.hu_struct_file_prefix
 624         if trait_doc_comment is not None:
 625             out_java_trait += "/**\n * " + trait_doc_comment.replace("\n", "\n * ") + "\n */\n"
 626         out_java_trait = out_java_trait + "public class " + struct_name.replace("LDK","") + " : CommonBase {\n"
 627         out_java_trait = out_java_trait + "\tinternal readonly bindings." + struct_name + " bindings_instance;\n"
 628         out_java_trait = out_java_trait + "\tinternal " + struct_name.replace("LDK", "") + "(object _dummy, long ptr) : base(ptr) { bindings_instance = null; }\n"
 629         out_java_trait = out_java_trait + "\tprivate " + struct_name.replace("LDK", "") + "(bindings." + struct_name + " arg"
 630         for var in flattened_field_vars:
 631             if isinstance(var, ConvInfo):
 632                 out_java_trait += ", " + var.java_hu_ty + " " + var.arg_name
 633             else:
 634                 out_java_trait += ", bindings." + var[0] + " " + var[1]
 635         out_java_trait += ") : base(bindings." + struct_name + "_new(arg"
 636         for var in flattened_field_vars:
 637             if isinstance(var, ConvInfo):
 638                 if var.from_hu_conv is not None:
 639                     out_java_trait = out_java_trait + ", " + var.from_hu_conv[0]
 640                 else:
 641                     out_java_trait = out_java_trait + ", " + var.arg_name
 642             else:
 643                 out_java_trait = out_java_trait + ", " + var[1]
 644         out_java_trait = out_java_trait + ")) {\n"
 645         out_java_trait = out_java_trait + "\t\tthis.ptrs_to.AddLast(arg);\n"
 646         for var in flattened_field_vars:
 647             if isinstance(var, ConvInfo):
 648                 if var.from_hu_conv is not None and var.from_hu_conv[1] != "":
 649                     out_java_trait = out_java_trait + "\t\t" + var.from_hu_conv[1].replace("\n", "\n\t\t") + ";\n"
 650             else:
 651                 out_java_trait = out_java_trait + "\t\tthis.ptrs_to.AddLast(" + var[1] + ");\n"
 652         out_java_trait = out_java_trait + "\t\tthis.bindings_instance = arg;\n"
 653         out_java_trait = out_java_trait + "\t}\n"
 654         out_java_trait = out_java_trait + "\t~" + struct_name.replace("LDK","") + "() {\n"
 655         out_java_trait = out_java_trait + "\t\tif (ptr != 0) { bindings." + struct_name.replace("LDK","") + "_free(ptr); }\n"
 656         out_java_trait = out_java_trait + "\t}\n\n"
 657
 658         java_trait_wrapper = "\tprivate class " + struct_name + "Holder { internal " + struct_name.replace("LDK", "") + " held; }\n"
 659         java_trait_wrapper += "\tprivate class " + struct_name + "Impl : bindings." + struct_name + " {\n"
 660         java_trait_wrapper += "\t\tinternal " + struct_name + "Impl(" + struct_name.replace("LDK", "") + "Interface arg, " + struct_name + "Holder impl_holder) { this.arg = arg; this.impl_holder = impl_holder; }\n"
 661         java_trait_wrapper += "\t\tprivate " + struct_name.replace("LDK", "") + "Interface arg;\n"
 662         java_trait_wrapper += "\t\tprivate " + struct_name + "Holder impl_holder;\n"
 663         java_trait_constr = "\tpublic static " + struct_name.replace("LDK", "") + " new_impl(" + struct_name.replace("LDK", "") + "Interface arg"
 664         for var in flattened_field_vars:
 665             if isinstance(var, ConvInfo):
 666                 java_trait_constr += ", " + var.java_hu_ty + " " + var.arg_name
 667             else:
 668                 # Ideally we'd be able to take any instance of the interface, but our C code can only represent
 669                 # Java-implemented version, so we require users pass a Java implementation here :/
 670                 java_trait_constr += ", " + var[0].replace("LDK", "") + "." + var[0].replace("LDK", "") + "Interface " + var[1] + "_impl"
 671         java_trait_constr = java_trait_constr + ") {\n\t\t" + struct_name + "Holder impl_holder = new " + struct_name + "Holder();\n"
 672         java_trait_constr = java_trait_constr + "\t\timpl_holder.held = new " + struct_name.replace("LDK", "") + "(new " + struct_name + "Impl(arg, impl_holder)"
 673         out_java_trait += "\tpublic interface " + struct_name.replace("LDK", "") + "Interface {\n"
 674         out_java += "\tpublic interface " + struct_name + " {\n"
 675         java_meths = []
 676         for fn_line in field_fns:
 677             java_meth_descr = "("
 678             if fn_line.fn_name != "free" and fn_line.fn_name != "cloned":
 679                 fn_name = fn_line.fn_name
 680                 if fn_name == "lock": # reserved symbol
 681                     fn_name = "do_lock"
 682                 out_java += "\t\t" + fn_line.ret_ty_info.java_ty + " " + fn_name + "("
 683                 java_trait_wrapper += "\t\tpublic " + fn_line.ret_ty_info.java_ty + " " + fn_name + "("
 684                 out_java_trait += "\t\t/**\n\t\t * " + fn_line.docs.replace("\n", "\n\t\t * ") + "\n\t\t */\n"
 685                 out_java_trait += "\t\t" + fn_line.ret_ty_info.java_hu_ty + " " + fn_name + "("
 686
 687                 for idx, arg_conv_info in enumerate(fn_line.args_ty):
 688                     if idx >= 1:
 689                         out_java += ", "
 690                         java_trait_wrapper += ", "
 691                         out_java_trait += ", "
 692                     out_java += arg_conv_info.java_ty + " _" + arg_conv_info.arg_name
 693                     out_java_trait += arg_conv_info.java_hu_ty + " _" + arg_conv_info.arg_name
 694                     java_trait_wrapper += arg_conv_info.java_ty + " _" + arg_conv_info.arg_name
 695                     java_meth_descr = java_meth_descr + arg_conv_info.java_fn_ty_arg
 696                 java_meth_descr = java_meth_descr + ")" + fn_line.ret_ty_info.java_fn_ty_arg
 697                 java_meths.append((fn_line.fn_name, java_meth_descr))
 698
 699                 out_java += ");\n"
 700                 out_java_trait += ");\n"
 701                 java_trait_wrapper += ") {\n"
 702
 703                 for arg_info in fn_line.args_ty:
 704                     if arg_info.to_hu_conv is not None:
 705                         java_trait_wrapper += "\t\t\t" + arg_info.to_hu_conv.replace("\n", "\n\t\t\t").replace(arg_info.arg_name, "_" + arg_info.arg_name) + "\n"
 706
 707                 if fn_line.ret_ty_info.java_ty != "void":
 708                     java_trait_wrapper += "\t\t\t" + fn_line.ret_ty_info.java_hu_ty + " ret = arg." + fn_name + "("
 709                 else:
 710                     java_trait_wrapper += "\t\t\targ." + fn_name + "("
 711
 712                 for idx, arg_info in enumerate(fn_line.args_ty):
 713                     if idx != 0:
 714                         java_trait_wrapper += ", "
 715                     if arg_info.to_hu_conv_name is not None:
 716                         java_trait_wrapper += arg_info.to_hu_conv_name.replace(arg_info.arg_name, "_" + arg_info.arg_name)
 717                     else:
 718                         java_trait_wrapper += "_" + arg_info.arg_name
 719
 720                 java_trait_wrapper += ");\n"
 721                 java_trait_wrapper += "\t\t\t\tGC.KeepAlive(arg);\n"
 722                 if fn_line.ret_ty_info.java_ty != "void":
 723                     if fn_line.ret_ty_info.from_hu_conv is not None:
 724                         java_trait_wrapper += "\t\t\t" + fn_line.ret_ty_info.java_ty + " result = " + fn_line.ret_ty_info.from_hu_conv[0] + ";\n"
 725                         if fn_line.ret_ty_info.from_hu_conv[1] != "":
 726                             java_trait_wrapper += "\t\t\t" + fn_line.ret_ty_info.from_hu_conv[1].replace("this", "impl_holder.held") + ";\n"
 727                         java_trait_wrapper += "\t\t\treturn result;\n"
 728                     else:
 729                         java_trait_wrapper += "\t\t\treturn ret;\n"
 730                 java_trait_wrapper += "\t\t}\n"
 731         java_trait_wrapper += "\t}"
 732         for var in field_vars:
 733             if isinstance(var, ConvInfo):
 734                 java_trait_constr = java_trait_constr + ", " + var.arg_name
 735             else:
 736                 java_trait_constr += ", " + var[1] + ".new_impl(" + var[1] + "_impl"
 737                 suptrait_constr = ""
 738                 for suparg in var[2]:
 739                     if isinstance(suparg, ConvInfo):
 740                         suptrait_constr += ", " + suparg.arg_name
 741                     else:
 742                         suptrait_constr += ", " + suparg[1] + "_impl"
 743                 java_trait_constr += suptrait_constr + ").bindings_instance"
 744                 for suparg in var[2]:
 745                     if isinstance(suparg, ConvInfo):
 746                         java_trait_constr += ", " + suparg.arg_name
 747                     else:
 748                         java_trait_constr += ", " + suparg[1] + ".new_impl("
 749                         # Blindly assume that we can just strip the first arg to build the args for the supertrait
 750                         java_trait_constr += suptrait_constr.split(", ", 1)[1]
 751                         java_trait_constr += ").bindings_instance"
 752         out_java_trait += "\t}\n" + java_trait_wrapper + "\n"
 753         out_java_trait += java_trait_constr + ");\n\t\treturn impl_holder.held;\n\t}\n"
 754
 755         out_java += "\t}\n"
 756
 757         out_java += self.native_meth_decl(struct_name + "_new", "long") + "(" + struct_name + " impl"
 758         for var in flattened_field_vars:
 759             if isinstance(var, ConvInfo):
 760                 out_java += ", " + var.java_ty + " " + var.arg_name
 761             else:
 762                 out_java += ", " + var[0] + " " + var[1]
 763         out_java += ");\n"
 764
 765         # Now that we've written out our java code (and created java_meths), generate C
 766         out_c = "typedef struct " + struct_name + "_JCalls {\n"
 767         out_c = out_c + "\tatomic_size_t refcnt;\n"
 768         out_c = out_c + "\tJavaVM *vm;\n"
 769         out_c = out_c + "\tjweak o;\n"
 770         for var in flattened_field_vars:
 771             if isinstance(var, ConvInfo):
 772                 # We're a regular ol' field
 773                 pass
 774             else:
 775                 # We're a supertrait
 776                 out_c = out_c + "\t" + var[0] + "_JCalls* " + var[1] + ";\n"
 777         for fn in field_fns:
 778             if fn.fn_name != "free" and fn.fn_name != "cloned":
 779                 out_c = out_c + "\tjmethodID " + fn.fn_name + "_meth;\n"
 780         out_c = out_c + "} " + struct_name + "_JCalls;\n"
 781
 782         for fn_line in field_fns:
 783             if fn_line.fn_name == "free":
 784                 out_c = out_c + "static void " + struct_name + "_JCalls_free(void* this_arg) {\n"
 785                 out_c = out_c + "\t" + struct_name + "_JCalls *j_calls = (" + struct_name + "_JCalls*) this_arg;\n"
 786                 out_c = out_c + "\tif (atomic_fetch_sub_explicit(&j_calls->refcnt, 1, memory_order_acquire) == 1) {\n"
 787                 out_c += "\t\t" + self.construct_jenv().replace("\n", "\n\t\t").strip() + "\n"
 788                 out_c = out_c + "\t\t(*env)->DeleteWeakGlobalRef(env, j_calls->o);\n"
 789                 out_c += "\t\t" + self.deconstruct_jenv().replace("\n", "\n\t\t").strip() + "\n"
 790                 out_c = out_c + "\t\tFREE(j_calls);\n"
 791                 out_c = out_c + "\t}\n}\n"
 792
 793         for idx, fn_line in enumerate(field_fns):
 794             if fn_line.fn_name != "free" and fn_line.fn_name != "cloned":
 795                 assert fn_line.ret_ty_info.ty_info.get_full_rust_ty()[1] == ""
 796                 out_c = out_c + fn_line.ret_ty_info.ty_info.get_full_rust_ty()[0] + " " + fn_line.fn_name + "_" + struct_name + "_jcall("
 797                 if fn_line.self_is_const:
 798                     out_c = out_c + "const void* this_arg"
 799                 else:
 800                     out_c = out_c + "void* this_arg"
 801
 802                 for idx, arg in enumerate(fn_line.args_ty):
 803                     out_c = out_c + ", " + arg.ty_info.get_full_rust_ty()[0] + " " + arg.arg_name + arg.ty_info.get_full_rust_ty()[1]
 804
 805                 out_c = out_c + ") {\n"
 806                 out_c = out_c + "\t" + struct_name + "_JCalls *j_calls = (" + struct_name + "_JCalls*) this_arg;\n"
 807                 out_c += "\t" + self.construct_jenv().replace("\n", "\n\t").strip() + "\n"
 808
 809                 for arg_info in fn_line.args_ty:
 810                     if arg_info.ret_conv is not None:
 811                         out_c = out_c + "\t" + arg_info.ret_conv[0].replace('\n', '\n\t')
 812                         out_c = out_c + arg_info.arg_name
 813                         out_c = out_c + arg_info.ret_conv[1].replace('\n', '\n\t') + "\n"
 814
 815                 out_c = out_c + "\tjobject obj = (*env)->NewLocalRef(env, j_calls->o);\n\tCHECK(obj != NULL);\n"
 816                 if fn_line.ret_ty_info.c_ty.endswith("Array"):
 817                     out_c = out_c + "\t" + fn_line.ret_ty_info.c_ty + " ret = (*env)->CallObjectMethod(env, obj, j_calls->" + fn_line.fn_name + "_meth"
 818                 elif fn_line.ret_ty_info.c_ty == "void":
 819                     out_c += "\t(*env)->CallVoidMethod(env, obj, j_calls->" + fn_line.fn_name + "_meth"
 820                 elif fn_line.ret_ty_info.java_hu_ty == "string" or "org/ldk/enums" in fn_line.ret_ty_info.java_fn_ty_arg:
 821                     # Manually write out string methods as they're just an Object
 822                     out_c += "\t" + fn_line.ret_ty_info.c_ty + " ret = (*env)->CallObjectMethod(env, obj, j_calls->" + fn_line.fn_name + "_meth"
 823                 elif not fn_line.ret_ty_info.passed_as_ptr:
 824                     out_c += "\t" + fn_line.ret_ty_info.c_ty + " ret = (*env)->Call" + fn_line.ret_ty_info.java_ty.title() + "Method(env, obj, j_calls->" + fn_line.fn_name + "_meth"
 825                 else:
 826                     out_c = out_c + "\tuint64_t ret = (*env)->CallLongMethod(env, obj, j_calls->" + fn_line.fn_name + "_meth"
 827
 828                 for idx, arg_info in enumerate(fn_line.args_ty):
 829                     if arg_info.ret_conv is not None:
 830                         out_c = out_c + ", " + arg_info.ret_conv_name
 831                     else:
 832                         out_c = out_c + ", " + arg_info.arg_name
 833                 out_c = out_c + ");\n"
 834
 835                 out_c += "\tif (UNLIKELY((*env)->ExceptionCheck(env))) {\n"
 836                 out_c += "\t\t(*env)->ExceptionDescribe(env);\n"
 837                 out_c += "\t\t(*env)->FatalError(env, \"A call to " + fn_line.fn_name + " in " + struct_name + " from rust threw an exception.\");\n"
 838                 out_c += "\t}\n"
 839
 840                 if fn_line.ret_ty_info.arg_conv is not None:
 841                     out_c += "\t" + fn_line.ret_ty_info.arg_conv.replace("\n", "\n\t") + "\n"
 842                     out_c += "\t" + self.deconstruct_jenv().replace("\n", "\n\t").strip() + "\n"
 843                     out_c += "\treturn " + fn_line.ret_ty_info.arg_conv_name + ";\n"
 844                 else:
 845                     out_c += "\t" + self.deconstruct_jenv().replace("\n", "\n\t").strip() + "\n"
 846                     if not fn_line.ret_ty_info.passed_as_ptr and fn_line.ret_ty_info.c_ty != "void":
 847                         out_c += "\treturn ret;\n"
 848
 849                 out_c = out_c + "}\n"
 850
 851         # If we can, write out a clone function whether we need one or not, as we use them in moving to rust
 852         can_clone_with_ptr = True
 853         for var in field_vars:
 854             if isinstance(var, ConvInfo):
 855                 can_clone_with_ptr = False
 856         if can_clone_with_ptr:
 857             out_c = out_c + "static void " + struct_name + "_JCalls_cloned(" + struct_name + "* new_obj) {\n"
 858             out_c = out_c + "\t" + struct_name + "_JCalls *j_calls = (" + struct_name + "_JCalls*) new_obj->this_arg;\n"
 859             out_c = out_c + "\tatomic_fetch_add_explicit(&j_calls->refcnt, 1, memory_order_release);\n"
 860             for var in field_vars:
 861                 if not isinstance(var, ConvInfo):
 862                     out_c = out_c + "\tatomic_fetch_add_explicit(&j_calls->" + var[1] + "->refcnt, 1, memory_order_release);\n"
 863             out_c = out_c + "}\n"
 864
 865         out_c = out_c + "static inline " + struct_name + " " + struct_name + "_init (" + self.c_fn_args_pfx + ", jobject o"
 866         for var in flattened_field_vars:
 867             if isinstance(var, ConvInfo):
 868                 out_c = out_c + ", " + var.c_ty + " " + var.arg_name
 869             else:
 870                 out_c = out_c + ", jobject " + var[1]
 871         out_c = out_c + ") {\n"
 872
 873         out_c = out_c + "\tjclass c = (*env)->GetObjectClass(env, o);\n"
 874         out_c = out_c + "\tCHECK(c != NULL);\n"
 875         out_c = out_c + "\t" + struct_name + "_JCalls *calls = MALLOC(sizeof(" + struct_name + "_JCalls), \"" + struct_name + "_JCalls\");\n"
 876         out_c = out_c + "\tatomic_init(&calls->refcnt, 1);\n"
 877         out_c = out_c + "\tDO_ASSERT((*env)->GetJavaVM(env, &calls->vm) == 0);\n"
 878         out_c = out_c + "\tcalls->o = (*env)->NewWeakGlobalRef(env, o);\n"
 879
 880         for (fn_name, java_meth_descr) in java_meths:
 881             if fn_name != "free" and fn_name != "cloned":
 882                 out_c = out_c + "\tcalls->" + fn_name + "_meth = (*env)->GetMethodID(env, c, \"" + fn_name + "\", \"" + java_meth_descr + "\");\n"
 883                 out_c = out_c + "\tCHECK(calls->" + fn_name + "_meth != NULL);\n"
 884
 885         for var in flattened_field_vars:
 886             if isinstance(var, ConvInfo) and var.arg_conv is not None:
 887                 out_c = out_c + "\n\t" + var.arg_conv.replace("\n", "\n\t") +"\n"
 888         out_c = out_c + "\n\t" + struct_name + " ret = {\n"
 889         out_c = out_c + "\t\t.this_arg = (void*) calls,\n"
 890         for fn_line in field_fns:
 891             if fn_line.fn_name != "free" and fn_line.fn_name != "cloned":
 892                 out_c = out_c + "\t\t." + fn_line.fn_name + " = " + fn_line.fn_name + "_" + struct_name + "_jcall,\n"
 893             elif fn_line.fn_name == "free":
 894                 out_c = out_c + "\t\t.free = " + struct_name + "_JCalls_free,\n"
 895             else:
 896                 out_c = out_c + "\t\t.cloned = " + struct_name + "_JCalls_cloned,\n"
 897         for var in field_vars:
 898             if isinstance(var, ConvInfo):
 899                 if var.arg_conv_name is not None:
 900                     out_c = out_c + "\t\t." + var.arg_name + " = " + var.arg_conv_name + ",\n"
 901                     out_c = out_c + "\t\t.set_" + var.arg_name + " = NULL,\n"
 902                 else:
 903                     out_c = out_c + "\t\t." + var.var_name + " = " + var.var_name + ",\n"
 904                     out_c = out_c + "\t\t.set_" + var.var_name + " = NULL,\n"
 905             else:
 906                 out_c += "\t\t." + var[1] + " = " + var[0] + "_init(env, clz, " + var[1]
 907                 for suparg in var[2]:
 908                     if isinstance(suparg, ConvInfo):
 909                         out_c = out_c + ", " + suparg.arg_name
 910                     else:
 911                         out_c = out_c + ", " + suparg[1]
 912                 out_c += "),\n"
 913         out_c = out_c + "\t};\n"
 914         for var in flattened_field_vars:
 915             if not isinstance(var, ConvInfo):
 916                 out_c = out_c + "\tcalls->" + var[1] + " = ret." + var[1] + ".this_arg;\n"
 917         out_c = out_c + "\treturn ret;\n"
 918         out_c = out_c + "}\n"
 919
 920         out_c += "int64_t " + self.c_fn_name_define_pfx(struct_name + "_new", True) + "jobject o"
 921         for var in flattened_field_vars:
 922             if isinstance(var, ConvInfo):
 923                 out_c = out_c + ", " + var.c_ty + " " + var.arg_name
 924             else:
 925                 out_c = out_c + ", jobject " + var[1]
 926         out_c = out_c + ") {\n"
 927         out_c = out_c + "\t" + struct_name + " *res_ptr = MALLOC(sizeof(" + struct_name + "), \"" + struct_name + "\");\n"
 928         out_c = out_c + "\t*res_ptr = " + struct_name + "_init(env, clz, o"
 929         for var in flattened_field_vars:
 930             if isinstance(var, ConvInfo):
 931                 out_c = out_c + ", " + var.arg_name
 932             else:
 933                 out_c = out_c + ", " + var[1]
 934         out_c = out_c + ");\n"
 935         out_c = out_c + "\treturn tag_ptr(res_ptr, true);\n"
 936         out_c = out_c + "}\n"
 937
 938         for var in flattened_field_vars:
 939             if not isinstance(var, ConvInfo):
 940                 out_java_trait += "\n\t/**\n"
 941                 out_java_trait += "\t * Gets the underlying " + var[1] + ".\n"
 942                 out_java_trait += "\t */\n"
 943                 underscore_name = ''.join('_' + c.lower() if c.isupper() else c for c in var[1]).strip('_')
 944                 out_java_trait += "\tpublic " + var[1] + " get_" + underscore_name + "() {\n"
 945                 out_java_trait += "\t\t" + var[1] + " res = new " + var[1] + "(null, bindings." + struct_name + "_get_" + var[1] + "(this.ptr));\n"
 946                 out_java_trait += "\t\tthis.ptrs_to.AddLast(res);\n"
 947                 out_java_trait += "\t\treturn res;\n"
 948                 out_java_trait += "\t}\n"
 949                 out_java_trait += "\n"
 950
 951                 out_java += self.native_meth_decl(struct_name + "_get_" + var[1], "long") + "(long arg);\n"
 952
 953                 out_c += "int64_t " + self.c_fn_name_define_pfx(struct_name + "_get_" + var[1], True) + "int64_t arg) {\n"
 954                 out_c += "\t" + struct_name + " *inp = (" + struct_name + " *)untag_ptr(arg);\n"
 955                 out_c += "\treturn tag_ptr(&inp->" + var[1] + ", false);\n"
 956                 out_c += "}\n"
 957
 958         return (out_java, out_java_trait, out_c)
 959
 960     def trait_struct_inc_refcnt(self, ty_info):
 961         base_conv = "\nif (" + ty_info.var_name + "_conv.free == " + ty_info.rust_obj + "_JCalls_free) {\n"
 962         base_conv = base_conv + "\t// If this_arg is a JCalls struct, then we need to increment the refcnt in it.\n"
 963         base_conv = base_conv + "\t" + ty_info.rust_obj + "_JCalls_cloned(&" + ty_info.var_name + "_conv);\n}"
 964         return base_conv
 965
 966     def map_complex_enum(self, struct_name, variant_list, camel_to_snake, enum_doc_comment):
 967         bindings_type = struct_name.replace("LDK", "")
 968         java_hu_type = struct_name.replace("LDK", "").replace("COption", "Option")
 969
 970         out_java_enum = ""
 971         out_java = ""
 972         out_c = ""
 973
 974         out_java_enum += (self.hu_struct_file_prefix)
 975
 976         java_hu_class = "/**\n * " + enum_doc_comment.replace("\n", "\n * ") + "\n */\n"
 977         java_hu_class += "public class " + java_hu_type + " : CommonBase {\n"
 978         java_hu_class += f"\tprotected {java_hu_type}(object _dummy, long ptr) : base(ptr)" + " { }\n"
 979         java_hu_class += "\t~" + java_hu_type + "() {\n"
 980         java_hu_class += "\t\tif (ptr != 0) { bindings." + bindings_type + "_free(ptr); }\n"
 981         java_hu_class += "\t}\n\n"
 982         java_hu_class += f"\tinternal static {java_hu_type} constr_from_ptr(long ptr) {{\n"
 983         java_hu_class += f"\t\tlong raw_ty = bindings." + struct_name + "_ty_from_ptr(ptr);\n"
 984         out_c += self.c_fn_ty_pfx + "uint32_t" + self.c_fn_name_define_pfx(struct_name + "_ty_from_ptr", True) + self.ptr_c_ty + " ptr) {\n"
 985         out_c += "\t" + struct_name + " *obj = (" + struct_name + "*)untag_ptr(ptr);\n"
 986         out_c += "\tswitch(obj->tag) {\n"
 987         java_hu_class += "\t\tswitch (raw_ty) {\n"
 988         java_hu_subclasses = ""
 989
 990         var_idx = 0
 991         for var in variant_list:
 992             java_hu_subclasses += "\t/** A " + java_hu_type + " of type " + var.var_name + " */\n"
 993             java_hu_subclasses += "\tpublic class " + java_hu_type + "_" + var.var_name + " : " + java_hu_type + " {\n"
 994             java_hu_class += f"\t\t\tcase {var_idx}: "
 995             java_hu_class += "return new " + java_hu_type + "_" + var.var_name + "(ptr);\n"
 996             out_c += f"\t\tcase {struct_name}_{var.var_name}: return {var_idx};\n"
 997             hu_conv_body = ""
 998             for idx, (field_ty, field_docs) in enumerate(var.fields):
 999                 if field_docs is not None:
1000                     java_hu_subclasses += "\t\t/**\n\t\t * " + field_docs.replace("\n", "\n\t\t * ") + "\n\t\t */\n"
1001                 java_hu_subclasses += f"\t\tpublic {field_ty.java_hu_ty} {field_ty.arg_name};\n"
1002                 if field_ty.to_hu_conv is not None:
1003                     hu_conv_body += f"\t\t\t{field_ty.java_ty} {field_ty.arg_name} = bindings.{struct_name}_{var.var_name}_get_{field_ty.arg_name}(ptr);\n"
1004                     hu_conv_body += f"\t\t\t" + field_ty.to_hu_conv.replace("\n", "\n\t\t\t") + "\n"
1005                     hu_conv_body += f"\t\t\tthis." + field_ty.arg_name + " = " + field_ty.to_hu_conv_name + ";\n"
1006                 else:
1007                     hu_conv_body += f"\t\t\tthis.{field_ty.arg_name} = bindings.{struct_name}_{var.var_name}_get_{field_ty.arg_name}(ptr);\n"
1008             java_hu_subclasses += "\t\tinternal " + java_hu_type + "_" + var.var_name + "(long ptr) : base(null, ptr) {\n"
1009             java_hu_subclasses += hu_conv_body
1010             java_hu_subclasses += "\t\t}\n\t}\n"
1011             var_idx += 1
1012         java_hu_class += "\t\t\tdefault:\n\t\t\t\tthrow new ArgumentException(\"Impossible enum variant\");\n\t\t}\n\t}\n\n"
1013         out_java += self.native_meth_decl(struct_name + "_ty_from_ptr", "long") + "(long ptr);\n"
1014         out_c += ("\t\tdefault: abort();\n")
1015         out_c += ("\t}\n}\n")
1016
1017         for var in variant_list:
1018             for idx, (field_map, _) in enumerate(var.fields):
1019                 fn_name = f"{struct_name}_{var.var_name}_get_{field_map.arg_name}"
1020                 out_c += self.c_fn_ty_pfx + field_map.c_ty + self.c_fn_name_define_pfx(fn_name, True) + self.ptr_c_ty + " ptr) {\n"
1021                 out_c += "\t" + struct_name + " *obj = (" + struct_name + "*)untag_ptr(ptr);\n"
1022                 out_c += f"\tassert(obj->tag == {struct_name}_{var.var_name});\n"
1023                 if field_map.ret_conv is not None:
1024                     out_c += ("\t\t\t" + field_map.ret_conv[0].replace("\n", "\n\t\t\t"))
1025                     if var.tuple_variant:
1026                         out_c += "obj->" + camel_to_snake(var.var_name)
1027                     else:
1028                         out_c += "obj->" + camel_to_snake(var.var_name) + "." + field_map.arg_name
1029                     out_c += (field_map.ret_conv[1].replace("\n", "\n\t\t\t") + "\n")
1030                     out_c += "\treturn " + field_map.ret_conv_name + ";\n"
1031                 else:
1032                     if var.tuple_variant:
1033                         out_c += "\treturn " + "obj->" + camel_to_snake(var.var_name) + ";\n"
1034                     else:
1035                         out_c += "\treturn " + "obj->" + camel_to_snake(var.var_name) + "." + field_map.arg_name + ";\n"
1036                 out_c += "}\n"
1037                 out_java += self.native_meth_decl(fn_name, field_map.java_ty) + "(long ptr);\n"
1038         out_java_enum += java_hu_class
1039         out_java_enum += java_hu_subclasses
1040         return (out_java, out_java_enum, out_c)
1041
1042     def map_opaque_struct(self, struct_name, struct_doc_comment):
1043         out_opaque_struct_human = ""
1044         out_opaque_struct_human += self.hu_struct_file_prefix
1045         out_opaque_struct_human += "\n/**\n * " + struct_doc_comment.replace("\n", "\n * ") + "\n */\n"
1046         hu_name = struct_name.replace("LDKC2Tuple", "TwoTuple").replace("LDKC3Tuple", "ThreeTuple").replace("LDK", "")
1047         out_opaque_struct_human += ("public class " + hu_name + " : CommonBase")
1048         if struct_name.startswith("LDKLocked") or struct_name.startswith("LDKReadOnly"):
1049             out_opaque_struct_human += (", IDisposable")
1050         out_opaque_struct_human += (" {\n")
1051         out_opaque_struct_human += ("\tinternal " + hu_name + "(object _dummy, long ptr) : base(ptr) { }\n")
1052         if struct_name.startswith("LDKLocked") or struct_name.startswith("LDKReadOnly"):
1053             out_opaque_struct_human += ("\tpublic void Dispose() {\n")
1054         else:
1055             out_opaque_struct_human += ("\t~" + hu_name + "() {\n")
1056         out_opaque_struct_human += ("\t\tif (ptr != 0) { bindings." + struct_name.replace("LDK","") + "_free(ptr); }\n")
1057         out_opaque_struct_human += ("\t}\n\n")
1058         return out_opaque_struct_human
1059
1060     def map_tuple(self, struct_name):
1061         return self.map_opaque_struct(struct_name, "A Tuple")
1062
1063     def map_result(self, struct_name, res_map, err_map):
1064         human_ty = struct_name.replace("LDKCResult", "Result")
1065         java_hu_struct = ""
1066         java_hu_struct += self.hu_struct_file_prefix
1067         java_hu_struct += "public class " + human_ty + " : CommonBase {\n"
1068         java_hu_struct += "\t" + human_ty + "(object _dummy, long ptr) : base(ptr) { }\n"
1069         java_hu_struct += "\t~" + human_ty + "() {\n"
1070         java_hu_struct += "\t\tif (ptr != 0) { bindings." + struct_name.replace("LDK","") + "_free(ptr); }\n"
1071         java_hu_struct += "\t}\n\n"
1072         java_hu_struct += "\tinternal static " + human_ty + " constr_from_ptr(long ptr) {\n"
1073         java_hu_struct += "\t\tif (bindings." + struct_name.replace("LDK", "") + "_is_ok(ptr)) {\n"
1074         java_hu_struct += "\t\t\treturn new " + human_ty + "_OK(null, ptr);\n"
1075         java_hu_struct += "\t\t} else {\n"
1076         java_hu_struct += "\t\t\treturn new " + human_ty + "_Err(null, ptr);\n"
1077         java_hu_struct += "\t\t}\n"
1078         java_hu_struct += "\t}\n"
1079
1080         java_hu_struct += "\tpublic class " + human_ty + "_OK : " + human_ty + " {\n"
1081
1082         if res_map.java_hu_ty != "void":
1083             java_hu_struct += "\t\tpublic readonly " + res_map.java_hu_ty + " res;\n"
1084         java_hu_struct += "\t\tinternal " + human_ty + "_OK(object _dummy, long ptr) : base(_dummy, ptr) {\n"
1085         if res_map.java_hu_ty == "void":
1086             pass
1087         elif res_map.to_hu_conv is not None:
1088             java_hu_struct += "\t\t\t" + res_map.java_ty + " res = bindings." + struct_name.replace("LDK", "") + "_get_ok(ptr);\n"
1089             java_hu_struct += "\t\t\t" + res_map.to_hu_conv.replace("\n", "\n\t\t\t")
1090             java_hu_struct += "\n\t\t\tthis.res = " + res_map.to_hu_conv_name + ";\n"
1091         else:
1092             java_hu_struct += "\t\t\tthis.res = bindings." + struct_name.replace("LDK", "") + "_get_ok(ptr);\n"
1093         java_hu_struct += "\t\t}\n"
1094         java_hu_struct += "\t}\n\n"
1095
1096         java_hu_struct += "\tpublic class " + human_ty + "_Err : " + human_ty + " {\n"
1097         if err_map.java_hu_ty != "void":
1098             java_hu_struct += "\t\tpublic readonly " + err_map.java_hu_ty + " err;\n"
1099         java_hu_struct += "\t\tinternal " + human_ty + "_Err(object _dummy, long ptr) : base(_dummy, ptr) {\n"
1100         if err_map.java_hu_ty == "void":
1101             pass
1102         elif err_map.to_hu_conv is not None:
1103             java_hu_struct += "\t\t\t" + err_map.java_ty + " err = bindings." + struct_name.replace("LDK", "") + "_get_err(ptr);\n"
1104             java_hu_struct += "\t\t\t" + err_map.to_hu_conv.replace("\n", "\n\t\t\t")
1105             java_hu_struct += "\n\t\t\tthis.err = " + err_map.to_hu_conv_name + ";\n"
1106         else:
1107             java_hu_struct += "\t\t\tthis.err = bindings." + struct_name.replace("LDK", "") + "_get_err(ptr);\n"
1108         java_hu_struct += "\t\t}\n"
1109
1110         java_hu_struct += "\t}\n\n"
1111         return java_hu_struct
1112
1113     def map_function(self, argument_types, c_call_string, method_name, meth_n, return_type_info, struct_meth, default_constructor_args, takes_self, takes_self_as_ref, args_known, type_mapping_generator, doc_comment):
1114         arg_name_repl = lambda s, arg_name: s.replace(arg_name, "_" + arg_name) if arg_name == "lock" or arg_name == "event" or arg_name == "params" else s
1115         out_java = ""
1116         out_c = ""
1117         out_java_struct = None
1118
1119         out_java += self.native_meth_decl(method_name, return_type_info.java_ty) + "("
1120         out_c += (return_type_info.c_ty)
1121         if return_type_info.ret_conv is not None:
1122             ret_conv_pfx, ret_conv_sfx = return_type_info.ret_conv
1123         have_args = len(argument_types) > 1 or (len(argument_types) > 0 and argument_types[0].c_ty != "void")
1124         out_c += (" " + self.c_fn_name_define_pfx(method_name, have_args))
1125
1126         for idx, arg_conv_info in enumerate(argument_types):
1127             if idx != 0:
1128                 out_java += (", ")
1129                 out_c += (", ")
1130             if arg_conv_info.c_ty != "void":
1131                 out_c += (arg_conv_info.c_ty + " " + arg_conv_info.arg_name)
1132                 out_java += (arg_conv_info.java_ty + " _" + arg_conv_info.arg_name) # Add a _ to avoid using reserved words
1133
1134         out_java_struct = ""
1135         extra_java_struct_out = ""
1136         if not args_known:
1137             out_java_struct += ("\t// Skipped " + method_name + "\n")
1138         else:
1139             if doc_comment is not None:
1140                 out_java_struct += "\t/**\n\t * " + doc_comment.replace("\n", "\n\t * ") + "\n\t */\n"
1141             hu_ret_ty = return_type_info.java_hu_ty
1142             if return_type_info.nullable:
1143                 #hu_ret_ty += "?" - apparently mono doesn't support the nullable stuff
1144                 pass
1145             if not takes_self:
1146                 if meth_n == "new":
1147                     out_java_struct += "\tpublic static " + hu_ret_ty + " of("
1148                 elif meth_n == "default":
1149                     out_java_struct += "\tpublic static " + hu_ret_ty + " with_default("
1150                 else:
1151                     out_java_struct += "\tpublic static " + hu_ret_ty + " " + meth_n + "("
1152             elif meth_n == "clone_ptr" or (struct_meth.startswith("LDKCResult") and (meth_n == "get_ok" or meth_n == "get_err")):
1153                 out_java_struct += "\tinternal " + hu_ret_ty + " " + meth_n + "("
1154             else:
1155                 if meth_n == "hash" and return_type_info.java_hu_ty == "long":
1156                     extra_java_struct_out = "\tpublic override int GetHashCode() {\n"
1157                     extra_java_struct_out += "\t\treturn (int)this.hash();\n"
1158                     extra_java_struct_out += "\t}\n"
1159                 elif meth_n == "eq" and return_type_info.java_hu_ty == "bool":
1160                     extra_java_struct_out = "\tpublic override bool Equals(object o) {\n"
1161                     extra_java_struct_out += "\t\tif (!(o is " + struct_meth + ")) return false;\n"
1162                     extra_java_struct_out += "\t\treturn this.eq((" + struct_meth + ")o);\n"
1163                     extra_java_struct_out += "\t}\n"
1164                 if meth_n == "lock":
1165                     out_java_struct += "\tpublic " + hu_ret_ty + " do_lock("
1166                 else:
1167                     out_java_struct += "\tpublic " + hu_ret_ty + " " + meth_n + "("
1168             for idx, arg in enumerate(argument_types):
1169                 if idx != 0:
1170                     if not takes_self or idx > 1:
1171                         out_java_struct += ", "
1172                 elif takes_self:
1173                     continue
1174                 if arg.java_ty != "void":
1175                     if arg.arg_name in default_constructor_args:
1176                         assert not arg.nullable
1177                         for explode_idx, explode_arg in enumerate(default_constructor_args[arg.arg_name]):
1178                             if explode_idx != 0:
1179                                 out_java_struct += (", ")
1180                             out_java_struct += (
1181                                 explode_arg.java_hu_ty + " " + arg.arg_name + "_" + explode_arg.arg_name)
1182                     else:
1183                         ty_string = arg.java_hu_ty
1184                         if arg.nullable:
1185                             #ty_string += "?" - apparently mono doesn't support the nullable stuff
1186                             pass
1187                         ty_string = self.fully_qualified_hu_ty_path(arg)
1188                         out_java_struct += ty_string + " " + arg_name_repl(arg.arg_name, arg.arg_name)
1189         out_java += (");\n")
1190         out_c += (") {\n")
1191         if out_java_struct is not None:
1192             out_java_struct += (") {\n")
1193         for info in argument_types:
1194             if info.arg_conv is not None:
1195                 out_c += ("\t" + info.arg_conv.replace('\n', "\n\t") + "\n")
1196         if return_type_info.ret_conv is not None:
1197             out_c += ("\t" + ret_conv_pfx.replace('\n', '\n\t'))
1198         elif return_type_info.c_ty != "void":
1199             out_c += ("\t" + return_type_info.c_ty + " ret_val = ")
1200         else:
1201             out_c += ("\t")
1202         if c_call_string is None:
1203             out_c += (method_name + "(")
1204         else:
1205             out_c += (c_call_string)
1206         for idx, info in enumerate(argument_types):
1207             if info.arg_conv_name is not None:
1208                 if idx != 0:
1209                     out_c += (", ")
1210                 elif c_call_string is not None:
1211                     continue
1212                 out_c += (info.arg_conv_name)
1213         out_c += (")")
1214         if return_type_info.ret_conv is not None:
1215             out_c += (ret_conv_sfx.replace('\n', '\n\t'))
1216         else:
1217             out_c += (";")
1218         for info in argument_types:
1219             if info.arg_conv_cleanup is not None:
1220                 out_c += ("\n\t" + info.arg_conv_cleanup.replace("\n", "\n\t"))
1221         if return_type_info.ret_conv is not None:
1222             out_c += ("\n\treturn " + return_type_info.ret_conv_name + ";")
1223         elif return_type_info.c_ty != "void":
1224             out_c += ("\n\treturn ret_val;")
1225         out_c += ("\n}\n\n")
1226
1227         if args_known:
1228             out_java_struct += ("\t\t")
1229             if return_type_info.java_ty != "void":
1230                 out_java_struct += (return_type_info.java_ty + " ret = ")
1231             out_java_struct += ("bindings." + method_name + "(")
1232             for idx, info in enumerate(argument_types):
1233                 if idx != 0:
1234                     out_java_struct += (", ")
1235                 if idx == 0 and takes_self:
1236                     out_java_struct += ("this.ptr")
1237                 elif info.arg_name in default_constructor_args:
1238                     out_java_struct += ("bindings." + info.java_hu_ty + "_new(")
1239                     for explode_idx, explode_arg in enumerate(default_constructor_args[info.arg_name]):
1240                         if explode_idx != 0:
1241                             out_java_struct += (", ")
1242                         expl_arg_name = info.arg_name + "_" + explode_arg.arg_name
1243                         if explode_arg.from_hu_conv is not None:
1244                             out_java_struct += (
1245                                 explode_arg.from_hu_conv[0].replace(explode_arg.arg_name, expl_arg_name))
1246                         else:
1247                             out_java_struct += (expl_arg_name)
1248                     out_java_struct += (")")
1249                 elif info.from_hu_conv is not None:
1250                     out_java_struct += arg_name_repl(info.from_hu_conv[0], info.arg_name)
1251                 else:
1252                     out_java_struct += arg_name_repl(info.arg_name, info.arg_name)
1253             out_java_struct += (");\n")
1254
1255             # Like Java, the C# GC is quite aggressive and can finalize an object while a method
1256             # on it is operating. Unlike Java, this behavior appears to be better documented,
1257             # which is nice.
1258             for idx, info in enumerate(argument_types):
1259                 if idx == 0 and takes_self:
1260                     out_java_struct += ("\t\tGC.KeepAlive(this);\n")
1261                 elif info.arg_name in default_constructor_args:
1262                     for explode_idx, explode_arg in enumerate(default_constructor_args[info.arg_name]):
1263                         expl_arg_name = info.arg_name + "_" + explode_arg.arg_name
1264                         out_java_struct += ("\t\tGC.KeepAlive(" + expl_arg_name + ");\n")
1265                 elif info.c_ty != "void":
1266                     out_java_struct += ("\t\tGC.KeepAlive(" + arg_name_repl(info.arg_name, info.arg_name) + ");\n")
1267
1268             if return_type_info.java_ty == "long" and return_type_info.java_hu_ty != "long":
1269                 out_java_struct += "\t\tif (ret >= 0 && ret <= 4096) { return null; }\n"
1270
1271             if return_type_info.to_hu_conv is not None:
1272                 if not takes_self:
1273                     out_java_struct += ("\t\t" + return_type_info.to_hu_conv.replace("\n", "\n\t\t")
1274                         .replace("this", return_type_info.to_hu_conv_name) + "\n")
1275                 else:
1276                     out_java_struct += ("\t\t" + return_type_info.to_hu_conv.replace("\n", "\n\t\t") + "\n")
1277
1278             for idx, info in enumerate(argument_types):
1279                 if idx == 0 and takes_self:
1280                     pass
1281                 elif info.arg_name in default_constructor_args:
1282                     for explode_arg in default_constructor_args[info.arg_name]:
1283                         expl_arg_name = info.arg_name + "_" + explode_arg.arg_name
1284                         if explode_arg.from_hu_conv is not None and return_type_info.to_hu_conv_name:
1285                             out_java_struct += ("\t\t" +
1286                                 arg_name_repl(explode_arg.from_hu_conv[1], info.arg_name)
1287                                 .replace(explode_arg.arg_name, expl_arg_name)
1288                                 .replace("this", return_type_info.to_hu_conv_name) + ";\n")
1289                 elif info.from_hu_conv is not None and info.from_hu_conv[1] != "":
1290                     if not takes_self and return_type_info.to_hu_conv_name is not None:
1291                         out_java_struct += ("\t\t" + arg_name_repl(info.from_hu_conv[1], info.arg_name)
1292                             .replace("this", return_type_info.to_hu_conv_name)
1293                             .replace("\n", "\n\t\t") + ";\n")
1294                     else:
1295                         out_java_struct += ("\t\t" + arg_name_repl(info.from_hu_conv[1], info.arg_name)
1296                             .replace("\n", "\n\t\t") + ";\n")
1297
1298             if takes_self and not takes_self_as_ref:
1299                 out_java_struct += "\t\t" + argument_types[0].from_hu_conv[1].replace("\n", "\n\t\t").replace("this_arg", "this") + ";\n"
1300             if return_type_info.to_hu_conv_name is not None:
1301                 out_java_struct += ("\t\treturn " + return_type_info.to_hu_conv_name + ";\n")
1302             elif return_type_info.java_ty != "void" and return_type_info.rust_obj != "LDK" + struct_meth:
1303                 out_java_struct += ("\t\treturn ret;\n")
1304             out_java_struct += ("\t}\n\n")
1305
1306         return (out_java, out_c, out_java_struct + extra_java_struct_out)
1307
1308     def cleanup(self):
1309         pass