api.h

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// Copyright 2012 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 V8_API_API_H_
#define V8_API_API_H_
 
#include <memory>
 
#include "include/v8-container.h"
#include "include/v8-external.h"
#include "include/v8-function-callback.h"
#include "include/v8-proxy.h"
#include "include/v8-typed-array.h"
#include "include/v8-wasm.h"
#include "src/base/contextual.h"
#include "src/execution/isolate.h"
#include "src/objects/bigint.h"
#include "src/objects/contexts.h"
#include "src/objects/js-array-buffer.h"
#include "src/objects/js-collection.h"
#include "src/objects/js-generator.h"
#include "src/objects/js-promise.h"
#include "src/objects/js-proxy.h"
#include "src/objects/objects.h"
#include "src/objects/shared-function-info.h"
#include "src/objects/source-text-module.h"
#include "src/objects/templates.h"
#include "src/utils/detachable-vector.h"
 
namespace v8 {
 
class DictionaryTemplate;
class Extension;
class Signature;
class Template;
 
namespace internal {
class JSArrayBufferView;
class JSFinalizationRegistry;
}  // namespace internal
 
namespace debug {
class AccessorPair;
class GeneratorObject;
class ScriptSource;
class Script;
class EphemeronTable;
}  // namespace debug
 
template <typename T, internal::ExternalPointerTag tag>
inline T ToCData(i::Isolate* isolate,
                 v8::internal::Tagged<v8::internal::Object> obj);
template <internal::ExternalPointerTag tag>
inline v8::internal::Address ToCData(
    v8::internal::Isolate* isolate,
    v8::internal::Tagged<v8::internal::Object> obj);
 
template <internal::ExternalPointerTag tag, typename T>
inline v8::internal::DirectHandle<
    v8::internal::UnionOf<v8::internal::Smi, v8::internal::Foreign>>
FromCData(v8::internal::Isolate* isolate, T obj);
 
template <internal::ExternalPointerTag tag>
inline v8::internal::DirectHandle<
    v8::internal::UnionOf<v8::internal::Smi, v8::internal::Foreign>>
FromCData(v8::internal::Isolate* isolate, v8::internal::Address obj);
 
class ApiFunction {
 public:
  explicit ApiFunction(v8::internal::Address addr) : addr_(addr) {}
  v8::internal::Address address() { return addr_; }
 
 private:
  v8::internal::Address addr_;
};
 
class RegisteredExtension {
 public:
  static void Register(std::unique_ptr<Extension>);
  static void UnregisterAll();
  Extension* extension() const { return extension_.get(); }
  RegisteredExtension* next() const { return next_; }
  static RegisteredExtension* first_extension() { return first_extension_; }
 
 private:
  explicit RegisteredExtension(Extension*);
  explicit RegisteredExtension(std::unique_ptr<Extension>);
  std::unique_ptr<Extension> extension_;
  RegisteredExtension* next_ = nullptr;
  static RegisteredExtension* first_extension_;
};
 
#define TO_LOCAL_LIST(V)                                                \
  V(ToLocal, AccessorPair, debug::AccessorPair)                         \
  V(ToLocal, NativeContext, Context)                                    \
  V(ToLocal, Object, Value)                                             \
  V(ToLocal, Module, Module)                                            \
  V(ToLocal, Name, Name)                                                \
  V(ToLocal, String, String)                                            \
  V(ToLocal, Symbol, Symbol)                                            \
  V(ToLocal, JSRegExp, RegExp)                                          \
  V(ToLocal, JSReceiver, Object)                                        \
  V(ToLocal, JSObject, Object)                                          \
  V(ToLocal, JSFunction, Function)                                      \
  V(ToLocal, JSArray, Array)                                            \
  V(ToLocal, JSMap, Map)                                                \
  V(ToLocal, JSSet, Set)                                                \
  V(ToLocal, JSProxy, Proxy)                                            \
  V(ToLocal, JSArrayBuffer, ArrayBuffer)                                \
  V(ToLocal, JSArrayBufferView, ArrayBufferView)                        \
  V(ToLocal, JSDataView, DataView)                                      \
  V(ToLocal, JSRabGsabDataView, DataView)                               \
  V(ToLocal, JSTypedArray, TypedArray)                                  \
  V(ToLocalShared, JSArrayBuffer, SharedArrayBuffer)                    \
  V(ToLocal, FunctionTemplateInfo, FunctionTemplate)                    \
  V(ToLocal, ObjectTemplateInfo, ObjectTemplate)                        \
  V(ToLocal, DictionaryTemplateInfo, DictionaryTemplate)                \
  V(SignatureToLocal, FunctionTemplateInfo, Signature)                  \
  V(MessageToLocal, Object, Message)                                    \
  V(PromiseToLocal, JSObject, Promise)                                  \
  V(StackTraceToLocal, StackTraceInfo, StackTrace)                      \
  V(StackFrameToLocal, StackFrameInfo, StackFrame)                      \
  V(NumberToLocal, Object, Number)                                      \
  V(IntegerToLocal, Object, Integer)                                    \
  V(Uint32ToLocal, Object, Uint32)                                      \
  V(ToLocal, BigInt, BigInt)                                            \
  V(ExternalToLocal, JSObject, External)                                \
  V(CallableToLocal, JSReceiver, Function)                              \
  V(ToLocalPrimitive, Object, Primitive)                                \
  V(FixedArrayToLocal, FixedArray, FixedArray)                          \
  V(PrimitiveArrayToLocal, FixedArray, PrimitiveArray)                  \
  V(ToLocal, ScriptOrModule, ScriptOrModule)                            \
  IF_WASM(V, ToLocal, WasmMemoryMapDescriptor, WasmMemoryMapDescriptor) \
  IF_WASM(V, ToLocal, WasmModuleObject, WasmModuleObject)
 
#define TO_LOCAL_NAME_LIST(V) \
  V(ToLocal)                  \
  V(ToLocalShared)            \
  V(SignatureToLocal)         \
  V(MessageToLocal)           \
  V(PromiseToLocal)           \
  V(StackTraceToLocal)        \
  V(StackFrameToLocal)        \
  V(NumberToLocal)            \
  V(IntegerToLocal)           \
  V(Uint32ToLocal)            \
  V(ExternalToLocal)          \
  V(CallableToLocal)          \
  V(ToLocalPrimitive)         \
  V(FixedArrayToLocal)        \
  V(PrimitiveArrayToLocal)
 
#define OPEN_HANDLE_LIST(V)                                    \
  V(Template, TemplateInfoWithProperties)                      \
  V(FunctionTemplate, FunctionTemplateInfo)                    \
  V(ObjectTemplate, ObjectTemplateInfo)                        \
  V(DictionaryTemplate, DictionaryTemplateInfo)                \
  V(Signature, FunctionTemplateInfo)                           \
  V(Data, Object)                                              \
  V(Number, Number)                                            \
  V(RegExp, JSRegExp)                                          \
  V(Object, JSReceiver)                                        \
  V(Array, JSArray)                                            \
  V(Map, JSMap)                                                \
  V(Set, JSSet)                                                \
  V(ArrayBuffer, JSArrayBuffer)                                \
  V(ArrayBufferView, JSArrayBufferView)                        \
  V(TypedArray, JSTypedArray)                                  \
  V(Uint8Array, JSTypedArray)                                  \
  V(Uint8ClampedArray, JSTypedArray)                           \
  V(Int8Array, JSTypedArray)                                   \
  V(Uint16Array, JSTypedArray)                                 \
  V(Int16Array, JSTypedArray)                                  \
  V(Uint32Array, JSTypedArray)                                 \
  V(Int32Array, JSTypedArray)                                  \
  V(Float16Array, JSTypedArray)                                \
  V(Float32Array, JSTypedArray)                                \
  V(Float64Array, JSTypedArray)                                \
  V(DataView, JSDataViewOrRabGsabDataView)                     \
  V(SharedArrayBuffer, JSArrayBuffer)                          \
  V(Name, Name)                                                \
  V(String, String)                                            \
  V(Symbol, Symbol)                                            \
  V(Script, JSFunction)                                        \
  V(UnboundModuleScript, SharedFunctionInfo)                   \
  V(UnboundScript, SharedFunctionInfo)                         \
  V(Module, Module)                                            \
  V(Function, JSReceiver)                                      \
  V(CompileHintsCollector, Script)                             \
  V(Message, JSMessageObject)                                  \
  V(Context, NativeContext)                                    \
  V(External, Object)                                          \
  V(StackTrace, StackTraceInfo)                                \
  V(StackFrame, StackFrameInfo)                                \
  V(Proxy, JSProxy)                                            \
  V(debug::GeneratorObject, JSGeneratorObject)                 \
  V(debug::ScriptSource, HeapObject)                           \
  V(debug::Script, Script)                                     \
  V(debug::EphemeronTable, EphemeronHashTable)                 \
  V(debug::AccessorPair, AccessorPair)                         \
  V(Promise, JSPromise)                                        \
  V(Primitive, Object)                                         \
  V(PrimitiveArray, FixedArray)                                \
  V(BigInt, BigInt)                                            \
  V(ScriptOrModule, ScriptOrModule)                            \
  V(FixedArray, FixedArray)                                    \
  V(ModuleRequest, ModuleRequest)                              \
  IF_WASM(V, WasmMemoryMapDescriptor, WasmMemoryMapDescriptor) \
  IF_WASM(V, WasmMemoryObject, WasmMemoryObject)
 
class Utils {
 public:
  static V8_INLINE bool ApiCheck(bool condition, const char* location,
                                 const char* message) {
    if (V8_UNLIKELY(!condition)) {
      Utils::ReportApiFailure(location, message);
    }
    return condition;
  }
  static void ReportOOMFailure(v8::internal::Isolate* isolate,
                               const char* location, const OOMDetails& details);
 
  // TODO(42203211): It would be nice if we could keep only a version with
  // direct handles. But the implicit conversion from handles to direct handles
  // combined with the heterogeneous copy constructor for direct handles make
  // this ambiguous.
  // TODO(42203211): Use C++20 concepts instead of the enable_if trait, when
  // they are fully supported in V8.
#define DECLARE_TO_LOCAL(Name)                                   \
  template <template <typename> typename HandleType, typename T, \
            typename = std::enable_if_t<std::is_convertible_v<   \
                HandleType<T>, v8::internal::DirectHandle<T>>>>  \
  static inline auto Name(HandleType<T> obj);
 
  TO_LOCAL_NAME_LIST(DECLARE_TO_LOCAL)
 
#define DECLARE_TO_LOCAL_TYPED_ARRAY(Type, typeName, TYPE, ctype) \
  static inline Local<v8::Type##Array> ToLocal##Type##Array(      \
      v8::internal::DirectHandle<v8::internal::JSTypedArray> obj);
 
  TYPED_ARRAYS(DECLARE_TO_LOCAL_TYPED_ARRAY)
 
#define DECLARE_OPEN_HANDLE(From, To)                                          \
  static inline v8::internal::Handle<v8::internal::To> OpenHandle(             \
      const From* that, bool allow_empty_handle = false);                      \
  static inline v8::internal::DirectHandle<v8::internal::To> OpenDirectHandle( \
      const From* that, bool allow_empty_handle = false);                      \
  static inline v8::internal::IndirectHandle<v8::internal::To>                 \
  OpenIndirectHandle(const From* that, bool allow_empty_handle = false);
 
  OPEN_HANDLE_LIST(DECLARE_OPEN_HANDLE)
 
#undef DECLARE_OPEN_HANDLE
#undef DECLARE_TO_LOCAL_TYPED_ARRAY
#undef DECLARE_TO_LOCAL
 
  template <class From, class To>
  static inline Local<To> Convert(v8::internal::DirectHandle<From> obj);
 
  template <class T>
  static inline v8::internal::Handle<v8::internal::Object> OpenPersistent(
      const v8::PersistentBase<T>& persistent) {
    return v8::internal::Handle<v8::internal::Object>(persistent.slot());
  }
 
  template <class T>
  static inline v8::internal::DirectHandle<v8::internal::Object> OpenPersistent(
      v8::Persistent<T>* persistent) {
    return OpenPersistent(*persistent);
  }
 
  template <class From, class To>
  static inline v8::internal::Handle<To> OpenHandle(v8::Local<From> handle) {
    return OpenHandle(*handle);
  }
 
  template <class From, class To>
  static inline v8::internal::DirectHandle<To> OpenDirectHandle(
      v8::Local<From> handle) {
    return OpenDirectHandle(*handle);
  }
 
 private:
  V8_NOINLINE V8_PRESERVE_MOST static void ReportApiFailure(
      const char* location, const char* message);
 
#define DECLARE_TO_LOCAL_PRIVATE(Name, From, To) \
  static inline Local<v8::To> Name##_helper(     \
      v8::internal::DirectHandle<v8::internal::From> obj);
 
  TO_LOCAL_LIST(DECLARE_TO_LOCAL_PRIVATE)
#undef DECLARE_TO_LOCAL_PRIVATE
};
 
template <class T>
inline v8::Local<T> ToApiHandle(
    v8::internal::DirectHandle<v8::internal::Object> obj) {
  return Utils::Convert<v8::internal::Object, T>(obj);
}
 
template <class T>
inline bool ToLocal(v8::internal::MaybeDirectHandle<v8::internal::Object> maybe,
                    Local<T>* local) {
  v8::internal::DirectHandle<v8::internal::Object> handle;
  if (maybe.ToHandle(&handle)) {
    *local = Utils::Convert<v8::internal::Object, T>(handle);
    return true;
  }
  return false;
}
 
namespace internal {
 
class PersistentHandles;
 
// This class is here in order to be able to declare it a friend of
// HandleScope.  Moving these methods to be members of HandleScope would be
// neat in some ways, but it would expose internal implementation details in
// our public header file, which is undesirable.
//
// An isolate has a single instance of this class to hold the current thread's
// data. In multithreaded V8 programs this data is copied in and out of storage
// so that the currently executing thread always has its own copy of this
// data.
class HandleScopeImplementer {
 public:
  class V8_NODISCARD EnteredContextRewindScope {
   public:
    explicit EnteredContextRewindScope(HandleScopeImplementer* hsi)
        : hsi_(hsi), saved_entered_context_count_(hsi->EnteredContextCount()) {}
 
    ~EnteredContextRewindScope() {
      DCHECK_LE(saved_entered_context_count_, hsi_->EnteredContextCount());
      while (saved_entered_context_count_ < hsi_->EnteredContextCount())
        hsi_->LeaveContext();
    }
 
   private:
    HandleScopeImplementer* hsi_;
    size_t saved_entered_context_count_;
  };
 
  explicit HandleScopeImplementer(Isolate* isolate)
      : isolate_(isolate), spare_(nullptr) {}
 
  ~HandleScopeImplementer() { DeleteArray(spare_); }
 
  HandleScopeImplementer(const HandleScopeImplementer&) = delete;
  HandleScopeImplementer& operator=(const HandleScopeImplementer&) = delete;
 
  // Threading support for handle data.
  static int ArchiveSpacePerThread();
  char* RestoreThread(char* from);
  char* ArchiveThread(char* to);
  void FreeThreadResources();
 
  // Garbage collection support.
  V8_EXPORT_PRIVATE void Iterate(v8::internal::RootVisitor* v);
  V8_EXPORT_PRIVATE static char* Iterate(v8::internal::RootVisitor* v,
                                         char* data);
 
  inline internal::Address* GetSpareOrNewBlock();
  inline void DeleteExtensions(internal::Address* prev_limit);
 
  inline void EnterContext(Tagged<NativeContext> context);
  inline void LeaveContext();
  inline bool LastEnteredContextWas(Tagged<NativeContext> context);
  inline size_t EnteredContextCount() const { return entered_contexts_.size(); }
 
  // Returns the last entered context or an empty handle if no
  // contexts have been entered.
  inline DirectHandle<NativeContext> LastEnteredContext();
 
  inline void SaveContext(Tagged<Context> context);
  inline Tagged<Context> RestoreContext();
  inline bool HasSavedContexts();
 
  inline DetachableVector<Address*>* blocks() { return &blocks_; }
  Isolate* isolate() const { return isolate_; }
 
  void ReturnBlock(Address* block) {
    DCHECK_NOT_NULL(block);
    if (spare_ != nullptr) DeleteArray(spare_);
    spare_ = block;
  }
 
  static const size_t kEnteredContextsOffset;
 
 private:
  void ResetAfterArchive() {
    blocks_.detach();
    entered_contexts_.detach();
    saved_contexts_.detach();
    spare_ = nullptr;
    last_handle_before_persistent_block_.reset();
  }
 
  void Free() {
    DCHECK(blocks_.empty());
    DCHECK(entered_contexts_.empty());
    DCHECK(saved_contexts_.empty());
 
    blocks_.free();
    entered_contexts_.free();
    saved_contexts_.free();
    if (spare_ != nullptr) {
      DeleteArray(spare_);
      spare_ = nullptr;
    }
    DCHECK(isolate_->thread_local_top()->CallDepthIsZero());
  }
 
  void BeginPersistentScope() {
    DCHECK(!last_handle_before_persistent_block_.has_value());
    last_handle_before_persistent_block_ = isolate()->handle_scope_data()->next;
  }
  bool HasPersistentScope() const {
    return last_handle_before_persistent_block_.has_value();
  }
  std::unique_ptr<PersistentHandles> DetachPersistent(Address* first_block);
 
  Isolate* isolate_;
  DetachableVector<Address*> blocks_;
 
  // Used as a stack to keep track of entered contexts.
  DetachableVector<Tagged<NativeContext>> entered_contexts_;
 
  // Used as a stack to keep track of saved contexts.
  DetachableVector<Tagged<Context>> saved_contexts_;
  Address* spare_;
  std::optional<Address*> last_handle_before_persistent_block_;
  // This is only used for threading support.
  HandleScopeData handle_scope_data_;
 
  void IterateThis(RootVisitor* v);
  char* RestoreThreadHelper(char* from);
  char* ArchiveThreadHelper(char* to);
 
  friend class HandleScopeImplementerOffsets;
  friend class PersistentHandlesScope;
};
 
const int kHandleBlockSize = v8::internal::KB - 2;  // fit in one page
 
void HandleScopeImplementer::SaveContext(Tagged<Context> context) {
  saved_contexts_.push_back(context);
}
 
Tagged<Context> HandleScopeImplementer::RestoreContext() {
  Tagged<Context> last_context = saved_contexts_.back();
  saved_contexts_.pop_back();
  return last_context;
}
 
bool HandleScopeImplementer::HasSavedContexts() {
  return !saved_contexts_.empty();
}
 
void HandleScopeImplementer::LeaveContext() {
  DCHECK(!entered_contexts_.empty());
  entered_contexts_.pop_back();
}
 
bool HandleScopeImplementer::LastEnteredContextWas(
    Tagged<NativeContext> context) {
  return !entered_contexts_.empty() && entered_contexts_.back() == context;
}
 
// If there's a spare block, use it for growing the current scope.
internal::Address* HandleScopeImplementer::GetSpareOrNewBlock() {
  internal::Address* block =
      (spare_ != nullptr) ? spare_
                          : NewArray<internal::Address>(kHandleBlockSize);
  spare_ = nullptr;
  return block;
}
 
void HandleScopeImplementer::DeleteExtensions(internal::Address* prev_limit) {
  while (!blocks_.empty()) {
    internal::Address* block_start = blocks_.back();
    internal::Address* block_limit = block_start + kHandleBlockSize;
 
    // SealHandleScope may make the prev_limit to point inside the block.
    // Cast possibly-unrelated pointers to plain Address before comparing them
    // to avoid undefined behavior.
    if (reinterpret_cast<Address>(block_start) <
            reinterpret_cast<Address>(prev_limit) &&
        reinterpret_cast<Address>(prev_limit) <=
            reinterpret_cast<Address>(block_limit)) {
#ifdef ENABLE_LOCAL_HANDLE_ZAPPING
      internal::HandleScope::ZapRange(prev_limit, block_limit);
#endif
      break;
    }
 
    blocks_.pop_back();
#ifdef ENABLE_LOCAL_HANDLE_ZAPPING
    internal::HandleScope::ZapRange(block_start, block_limit);
#endif
    if (spare_ != nullptr) {
      DeleteArray(spare_);
    }
    spare_ = block_start;
  }
  DCHECK((blocks_.empty() && prev_limit == nullptr) ||
         (!blocks_.empty() && prev_limit != nullptr));
}
 
// This is a wrapper function called from CallApiGetter builtin when profiling
// or side-effect checking is enabled. It's supposed to set up the runtime
// call stats scope and check if the getter has side-effects in case debugger
// enabled the side-effects checking mode.
// It gets additional argument, the AccessorInfo object, via
// IsolateData::api_callback_thunk_argument slot.
void InvokeAccessorGetterCallback(
    v8::Local<v8::Name> property,
    const v8::PropertyCallbackInfo<v8::Value>& info);
 
// This is a wrapper function called from CallApiCallback builtin when profiling
// or side-effect checking is enabled. It's supposed to set up the runtime
// call stats scope and check if the callback has side-effects in case debugger
// enabled the side-effects checking mode.
// It gets additional argument, the v8::FunctionCallback address, via
// IsolateData::api_callback_thunk_argument slot.
void InvokeFunctionCallbackGeneric(
    const v8::FunctionCallbackInfo<v8::Value>& info);
void InvokeFunctionCallbackOptimized(
    const v8::FunctionCallbackInfo<v8::Value>& info);
 
void InvokeFinalizationRegistryCleanupFromTask(
    DirectHandle<NativeContext> native_context,
    DirectHandle<JSFinalizationRegistry> finalization_registry);
 
template <typename T>
EXPORT_TEMPLATE_DECLARE(V8_EXPORT_PRIVATE)
T ConvertDouble(double d);
 
template <typename T>
EXPORT_TEMPLATE_DECLARE(V8_EXPORT_PRIVATE)
bool ValidateCallbackInfo(const FunctionCallbackInfo<T>& info);
 
template <typename T>
EXPORT_TEMPLATE_DECLARE(V8_EXPORT_PRIVATE)
bool ValidateCallbackInfo(const PropertyCallbackInfo<T>& info);
 
#ifdef ENABLE_SLOW_DCHECKS
DECLARE_CONTEXTUAL_VARIABLE_WITH_DEFAULT(StackAllocatedCheck, const bool, true);
#endif
 
}  // namespace internal
}  // namespace v8
 
#endif  // V8_API_API_H_