v8-snapshot.h

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// Copyright 2021 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#ifndef INCLUDE_V8_SNAPSHOT_H_
#define INCLUDE_V8_SNAPSHOT_H_
 
#include "v8-internal.h"      // NOLINT(build/include_directory)
#include "v8-local-handle.h"  // NOLINT(build/include_directory)
#include "v8config.h"         // NOLINT(build/include_directory)
 
namespace v8 {
 
class Object;
 
class V8_EXPORT StartupData {
 public:
  bool CanBeRehashed() const;
  bool IsValid() const;
 
  const char* data;
  int raw_size;
};
 
struct SerializeInternalFieldsCallback {
  using CallbackFunction = StartupData (*)(Local<Object> holder, int index,
                                           void* data);
  SerializeInternalFieldsCallback(CallbackFunction function = nullptr,
                                  void* data_arg = nullptr)
      : callback(function), data(data_arg) {}
  CallbackFunction callback;
  void* data;
};
// Note that these fields are called "internal fields" in the API and called
// "embedder fields" within V8.
using SerializeEmbedderFieldsCallback = SerializeInternalFieldsCallback;
 
struct DeserializeInternalFieldsCallback {
  using CallbackFunction = void (*)(Local<Object> holder, int index,
                                    StartupData payload, void* data);
  DeserializeInternalFieldsCallback(CallbackFunction function = nullptr,
                                    void* data_arg = nullptr)
      : callback(function), data(data_arg) {}
  void (*callback)(Local<Object> holder, int index, StartupData payload,
                   void* data);
  void* data;
};
 
using DeserializeEmbedderFieldsCallback = DeserializeInternalFieldsCallback;
 
class V8_EXPORT SnapshotCreator {
 public:
  enum class FunctionCodeHandling { kClear, kKeep };
 
  SnapshotCreator(Isolate* isolate,
                  const intptr_t* external_references = nullptr,
                  StartupData* existing_blob = nullptr);
 
  SnapshotCreator(const intptr_t* external_references = nullptr,
                  StartupData* existing_blob = nullptr);
 
  ~SnapshotCreator();
 
  Isolate* GetIsolate();
 
  void SetDefaultContext(Local<Context> context,
                         SerializeInternalFieldsCallback callback =
                             SerializeInternalFieldsCallback());
 
  size_t AddContext(Local<Context> context,
                    SerializeInternalFieldsCallback callback =
                        SerializeInternalFieldsCallback());
 
  template <class T>
  V8_INLINE size_t AddData(Local<Context> context, Local<T> object);
 
  template <class T>
  V8_INLINE size_t AddData(Local<T> object);
 
  StartupData CreateBlob(FunctionCodeHandling function_code_handling);
 
  // Disallow copying and assigning.
  SnapshotCreator(const SnapshotCreator&) = delete;
  void operator=(const SnapshotCreator&) = delete;
 
 private:
  size_t AddData(Local<Context> context, internal::Address object);
  size_t AddData(internal::Address object);
 
  void* data_;
};
 
template <class T>
size_t SnapshotCreator::AddData(Local<Context> context, Local<T> object) {
  T* object_ptr = *object;
  internal::Address* p = reinterpret_cast<internal::Address*>(object_ptr);
  return AddData(context, *p);
}
 
template <class T>
size_t SnapshotCreator::AddData(Local<T> object) {
  T* object_ptr = *object;
  internal::Address* p = reinterpret_cast<internal::Address*>(object_ptr);
  return AddData(*p);
}
 
}  // namespace v8
 
#endif  // INCLUDE_V8_SNAPSHOT_H_