samples/embedder/helpers.h

/*
 * Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
 * for details. All rights reserved. Use of this source code is governed by a
 * BSD-style license that can be found in the LICENSE file.
 */

#ifndef SAMPLES_EMBEDDER_HELPERS_H_
#define SAMPLES_EMBEDDER_HELPERS_H_

#include <functional>
#include <iostream>
#include <string>
#include <string_view>
#include "include/dart_api.h"
#include "include/dart_engine.h"

// Loads kernel/AOT snapshot from path depending on
// whether we use precompiled runtime.
inline DartEngine_SnapshotData AutoSnapshotFromFile(std::string_view path,
                                                    char** error) {
  std::string path_string(path);
  if (Dart_IsPrecompiledRuntime()) {
    return DartEngine_AotSnapshotFromFile(path_string.c_str(), error);
  } else {
    return DartEngine_KernelFromFile(path_string.c_str(), error);
  }
}

inline void CheckError(char* error, std::string_view context = "") {
  if (error != nullptr) {
    std::cerr << "Error " << context << ": " << error << std::endl;
    std::exit(1);
  }
}

inline Dart_Handle CheckError(Dart_Handle handle,
                              std::string_view context = "") {
  if (Dart_IsError(handle)) {
    std::cerr << "Error " << context << ": " << Dart_GetError(handle)
              << std::endl;
    std::exit(1);
  }
  return handle;
}

inline std::string StringFromHandle(Dart_Handle handle) {
  CheckError(handle, "StringFromHandle received an error");

  if (!Dart_IsString(handle)) {
    std::cerr << "StringFromHandle handle is not a string" << std::endl;
    std::exit(1);
  }

  const char* return_value_tmp;
  Dart_Handle to_string_result =
      Dart_StringToCString(handle, &return_value_tmp);
  CheckError(to_string_result, "Dart_StringToCString");

  return std::string(return_value_tmp);
}

inline int64_t IntFromHandle(Dart_Handle handle) {
  CheckError(handle, "IntFromHandle received an error");

  if (!Dart_IsInteger(handle)) {
    std::cerr << "IntFromHandle handle is not an int" << std::endl;
    std::exit(1);
  }

  int64_t result;
  Dart_Handle to_int64_result = Dart_IntegerToInt64(handle, &result);
  CheckError(to_int64_result, "Dart_IntegerToInt64");
  return result;
}

class DartScope {
 public:
  DartScope() { Dart_EnterScope(); }
  virtual ~DartScope() { Dart_ExitScope(); }

 private:
  DartScope(const DartScope&) = delete;
  void operator=(const DartScope&) = delete;
};

class IsolateScope {
 public:
  explicit IsolateScope(Dart_Isolate isolate) {
    DartEngine_AcquireIsolate(isolate);
  }
  virtual ~IsolateScope() { DartEngine_ReleaseIsolate(); }

 private:
  IsolateScope(const IsolateScope&) = delete;
  void operator=(const IsolateScope&) = delete;
};

template <typename T>
inline T WithIsolate(Dart_Isolate isolate, std::function<T()> body) {
  IsolateScope isolate_scope(isolate);
  DartScope dart_scope;

  return body();
}

#endif /* SAMPLES_EMBEDDER_HELPERS_H_ */