Add Node and C++ exception wrappers

src/genny/languages/cpp.nim

@@ -7,6 +7,7 @@ var
   procs {.compiletime.}: string
   classes {.compiletime.}: string
   members {.compiletime.}: string
+  hasRaisingProcs {.compiletime.}: bool
 
 proc unCapitalize(s: string): string =
   s[0].toLowerAscii() & s[1 .. ^1]
@@ -121,6 +122,31 @@ proc cppReturnValue(returnType: NimNode, call: string): string =
   else:
     call
 
+proc addCppCall(
+  returnType: NimNode,
+  call: string,
+  raises: bool
+) =
+  if not raises:
+    members.add "  "
+    if returnType.kind != nnkEmpty:
+      members.add "return "
+    members.add cppReturnValue(returnType, call)
+    members.add ";\n"
+    return
+
+  hasRaisingProcs = true
+  if returnType.kind == nnkEmpty:
+    members.add &"  {call};\n"
+    members.add "  throwIfError();\n"
+  else:
+    members.add &"  auto result = {call};\n"
+    if returnType.isStringType:
+      members.add "  throwIfError(result);\n"
+    else:
+      members.add "  throwIfError();\n"
+    members.add &"  return {cppReturnValue(returnType, \"result\")};\n"
+
 proc dllProc*(procName: string, args: openarray[string], restype: string) =
   var argStr = ""
   for arg in args:
@@ -160,6 +186,7 @@ proc exportProcCpp*(
     procType = sym.getTypeInst()
     procParams = procType[0][1 .. ^1]
     procReturn = procType[0][0]
+    procRaises = sym.raises()
 
   var apiProcName = ""
   if owner != nil:
@@ -190,17 +217,13 @@ proc exportProcCpp*(
       members.add ", "
     members.removeSuffix ", "
     members.add ") {\n"
-    members.add "  "
-    if procReturn.kind != nnkEmpty:
-      members.add "return "
     var call = &"$lib_{apiProcName}("
     for param in procParams:
       call.add cppArgValue(param[1], param[0].getParamName())
       call.add ", "
     call.removeSuffix ", "
     call.add ")"
-    members.add cppReturnValue(procReturn, call)
-    members.add ";\n"
+    addCppCall(procReturn, call, procRaises)
     members.add "};\n\n"
 
   else:
@@ -240,18 +263,13 @@ proc exportProcCpp*(
     members.removeSuffix ", "
     members.add ") "
     members.add "{\n"
-    if procReturn.kind == nnkEmpty:
-      members.add &"  "
-    else:
-      members.add &"  return "
     var call = &"$lib_{apiProcName}(*this, "
     for param in procParams[1..^1]:
       call.add cppArgValue(param[1], param[0].getParamName())
       call.add ", "
     call.removeSuffix ", "
     call.add ")"
-    members.add cppReturnValue(procReturn, call)
-    members.add ";\n"
+    addCppCall(procReturn, call, procRaises)
     members.add "};\n\n"
 
 proc exportObjectCpp*(
@@ -435,13 +453,17 @@ proc exportRefObjectCpp*(
       members.removeSuffix ", "
       members.add ")"
       members.add " {\n"
-      members.add &"  this->reference = "
+      members.add &"  auto result = "
       members.add  &"{constructorLibProc}("
       for param in constructorParams:
         members.add cppArgValue(param[1], param[0].getParamName())
         members.add ", "
       members.removeSuffix ", "
-      members.add ").reference;\n"
+      members.add ");\n"
+      if constructorRaises:
+        hasRaisingProcs = true
+        members.add "  throwIfError();\n"
+      members.add "  this->reference = result.reference;\n"
       members.add "}\n\n"
 
       var dllParams: seq[(NimNode, NimNode)]
@@ -562,6 +584,7 @@ const header = """
 
 #include <cstddef>
 #include <cstdint>
+#include <stdexcept>
 #include <string>
 
 """
@@ -616,11 +639,36 @@ void GennyBuffer::free() {
 
 """
 
+const errorMembers = """
+struct $LibException : public std::runtime_error {
+  explicit $LibException(const std::string& message) : std::runtime_error(message) {}
+};
+
+static inline void throwIfError() {
+  if ($lib_check_error()) {
+    throw $LibException(gennyBufferToString($lib_take_error()));
+  }
+}
+
+static inline void throwIfError(GennyBuffer buffer) {
+  if ($lib_check_error()) {
+    $lib_genny_buffer_unref(buffer);
+    throw $LibException(gennyBufferToString($lib_take_error()));
+  }
+}
+
+"""
+
 const footer = """
 #endif
 """
 
 proc writeCpp*(dir, lib: string) =
+  let errorBlock =
+    if hasRaisingProcs:
+      errorMembers
+    else:
+      ""
   createDir(dir)
   writeFile(&"{dir}/{toSnakeCase(lib)}.hpp", (
       header &
@@ -632,7 +680,8 @@ proc writeCpp*(dir, lib: string) =
       procs &
       "}\n\n" &
       bufferMembers &
+      errorBlock &
       members &
       footer
-    ).replace("$lib", toSnakeCase(lib)).replace("$LIB", lib.toUpperAscii())
+    ).replace("$Lib", lib).replace("$lib", toSnakeCase(lib)).replace("$LIB", lib.toUpperAscii())
   )

src/genny/languages/node.nim

@@ -116,6 +116,30 @@ proc jsReturnValue(returnType: NimNode, call: string): string =
   else:
     call
 
+proc addNodeCall(
+  returnType: NimNode,
+  call: string,
+  raises: bool
+) =
+  if not raises:
+    types.add "  "
+    if returnType.kind != nnkEmpty:
+      types.add "return "
+    types.add jsReturnValue(returnType, call)
+    types.add ";\n"
+    return
+
+  if returnType.kind == nnkEmpty:
+    types.add &"  {call};\n"
+    types.add "  throwIfError();\n"
+  else:
+    types.add &"  const result = {call};\n"
+    if returnType.isStringType:
+      types.add "  throwIfError(result);\n"
+    else:
+      types.add "  throwIfError();\n"
+    types.add &"  return {jsReturnValue(returnType, \"result\")};\n"
+
 proc convertExportFromNode*(sym: NimNode): string =
   discard
 
@@ -219,9 +243,6 @@ proc exportProcNode*(
       types.add &", "
   types.removeSuffix ", "
   types.add ") {\n"
-  types.add "  "
-  if procReturn.kind != nnkEmpty:
-    types.add "return "
   var call = &"{apiProcName}("
   for i, param in procParams[0 .. ^1]:
     if isRefObject and i == 0:
@@ -232,8 +253,7 @@ proc exportProcNode*(
     call.add &", "
   call.removeSuffix ", "
   call.add ")"
-  types.add jsReturnValue(procReturn, call)
-  types.add ";\n"
+  addNodeCall(procReturn, call, procRaises)
   types.add "}\n\n"
 
 proc exportObjectNode*(
@@ -343,6 +363,7 @@ proc exportRefObjectNode*(
       constructorLibProc = &"$lib_{toSnakeCase(constructor.repr)}"
       constructorType = constructor.getTypeInst()
       constructorParams = constructorType[0][1 .. ^1]
+      constructorRaises = constructor.raises()
 
     # Declare constructor C function
     declareFunc(constructorLibProc, constructorParams, "'uint64'")
@@ -361,6 +382,8 @@ proc exportRefObjectNode*(
       types.add ", "
     types.removeSuffix ", "
     types.add ");\n"
+    if constructorRaises:
+      types.add "  throwIfError();\n"
     types.add &"  return new {objName}(ref);\n"
     types.add "}\n\n"
 
@@ -477,6 +500,17 @@ class $LibException extends Error {
   }
 }
 
+exports.$LibException = $LibException;
+
+function throwIfError(buffer = null) {
+  if (checkError()) {
+    if (buffer !== null && buffer !== 0 && buffer !== 0n) {
+      $lib_genny_buffer_unref(buffer);
+    }
+    throw new $LibException(takeError());
+  }
+}
+
 function runeToInt(value) {
   assert.strictEqual(typeof value, 'string', 'expected rune string');
   const chars = Array.from(value);

tests/generated/internal.nim

@@ -27,6 +27,24 @@ proc test_genny_buffer_unref*(buffer: GennyBuffer) {.raises: [], cdecl, exportc,
 proc test_simple_call*(a: int): int {.raises: [], cdecl, exportc, dynlib.} =
   simpleCall(a)
 
+proc test_check_error*(): bool {.raises: [], cdecl, exportc, dynlib.} =
+  checkError()
+
+proc test_take_error*(): GennyBuffer {.raises: [], cdecl, exportc, dynlib.} =
+  newGennyBuffer(takeError())
+
+proc test_maybe_message*(message: cstring, fail: bool): GennyBuffer {.raises: [], cdecl, exportc, dynlib.} =
+  try:
+    result = newGennyBuffer(maybeMessage(message.`$`, fail))
+  except testError as e:
+    lastError = e
+
+proc test_maybe_number*(value: int, fail: bool): int {.raises: [], cdecl, exportc, dynlib.} =
+  try:
+    result = maybeNumber(value, fail)
+  except testError as e:
+    lastError = e
+
 proc test_simple_obj*(simple_a: int, simple_b: byte, simple_c: bool): SimpleObj {.raises: [], cdecl, exportc, dynlib.} =
   result.simple_a = simple_a
   result.simple_b = simple_b

tests/generated/test.h

@@ -49,6 +49,14 @@ void test_genny_buffer_unref(GennyBuffer buffer);
  */
 intptr_t test_simple_call(intptr_t a);
 
+char test_check_error();
+
+GennyBuffer test_take_error();
+
+GennyBuffer test_maybe_message(const char* message, char fail);
+
+intptr_t test_maybe_number(intptr_t value, char fail);
+
 SimpleObj test_simple_obj(intptr_t simple_a, uint8_t simple_b, char simple_c);
 
 char test_simple_obj_eq(SimpleObj a, SimpleObj b);

tests/generated/test.hpp

@@ -3,6 +3,7 @@
 
 #include <cstddef>
 #include <cstdint>
+#include <stdexcept>
 #include <string>
 
 static constexpr auto SIMPLE_CONST = 123;
@@ -157,6 +158,14 @@ void test_genny_buffer_unref(GennyBuffer buffer);
 
 std::intptr_t test_simple_call(std::intptr_t a);
 
+bool test_check_error();
+
+GennyBuffer test_take_error();
+
+GennyBuffer test_maybe_message(const char* message, bool fail);
+
+std::intptr_t test_maybe_number(std::intptr_t value, bool fail);
+
 SimpleObj test_simple_obj(std::intptr_t simple_a, std::uint8_t simple_b, bool simple_c);
 
 bool test_simple_obj_eq(SimpleObj a, SimpleObj b);
@@ -262,16 +271,54 @@ void GennyBuffer::free() {
   test_genny_buffer_unref(*this);
 }
 
+struct testException : public std::runtime_error {
+  explicit testException(const std::string& message) : std::runtime_error(message) {}
+};
+
+static inline void throwIfError() {
+  if (test_check_error()) {
+    throw testException(gennyBufferToString(test_take_error()));
+  }
+}
+
+static inline void throwIfError(GennyBuffer buffer) {
+  if (test_check_error()) {
+    test_genny_buffer_unref(buffer);
+    throw testException(gennyBufferToString(test_take_error()));
+  }
+}
+
 std::intptr_t simpleCall(std::intptr_t a) {
   return test_simple_call(a);
 };
 
+bool checkError() {
+  return test_check_error();
+};
+
+std::string takeError() {
+  return gennyBufferToString(test_take_error());
+};
+
+std::string maybeMessage(const char* message, bool fail) {
+  auto result = test_maybe_message(message, fail);
+  throwIfError(result);
+  return gennyBufferToString(result);
+};
+
+std::intptr_t maybeNumber(std::intptr_t value, bool fail) {
+  auto result = test_maybe_number(value, fail);
+  throwIfError();
+  return result;
+};
+
 SimpleObj simpleObj(std::intptr_t simpleA, std::uint8_t simpleB, bool simpleC) {
   return test_simple_obj(simpleA, simpleB, simpleC);
 };
 
 SimpleRefObj::SimpleRefObj() {
-  this->reference = test_new_simple_ref_obj().reference;
+  auto result = test_new_simple_ref_obj();
+  this->reference = result.reference;
 }
 
 std::intptr_t SimpleRefObj::getSimpleRefA(){
@@ -335,7 +382,8 @@ void SeqInt::free(){
 }
 
 RefObjWithSeq::RefObjWithSeq() {
-  this->reference = test_new_ref_obj_with_seq().reference;
+  auto result = test_new_ref_obj_with_seq();
+  this->reference = result.reference;
 }
 
 std::intptr_t RefObjWithSeq::dataSize(){