src/objects/js-proxy.h

// Copyright 2018 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_OBJECTS_JS_PROXY_H_
#define V8_OBJECTS_JS_PROXY_H_

#include "src/objects/js-objects.h"

// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"

namespace v8 {
namespace internal {

// The JSProxy describes EcmaScript Harmony proxies
class JSProxy : public JSReceiver {
 public:
  V8_WARN_UNUSED_RESULT static MaybeHandle<JSProxy> New(Isolate* isolate,
                                                        Handle<Object>,
                                                        Handle<Object>);

  // [handler]: The handler property.
  DECL_ACCESSORS(handler, Object)
  // [target]: The target property.
  DECL_ACCESSORS(target, Object)

  static MaybeHandle<Context> GetFunctionRealm(Handle<JSProxy> proxy);

  DECL_CAST(JSProxy)

  V8_INLINE bool IsRevoked() const;
  static void Revoke(Handle<JSProxy> proxy);

  // ES6 9.5.1
  static MaybeHandle<Object> GetPrototype(Handle<JSProxy> receiver);

  // ES6 9.5.2
  V8_WARN_UNUSED_RESULT static Maybe<bool> SetPrototype(
      Handle<JSProxy> proxy, Handle<Object> value, bool from_javascript,
      ShouldThrow should_throw);
  // ES6 9.5.3
  V8_WARN_UNUSED_RESULT static Maybe<bool> IsExtensible(Handle<JSProxy> proxy);

  // ES6, #sec-isarray.  NOT to be confused with %_IsArray.
  V8_WARN_UNUSED_RESULT static Maybe<bool> IsArray(Handle<JSProxy> proxy);

  // ES6 9.5.4 (when passed kDontThrow)
  V8_WARN_UNUSED_RESULT static Maybe<bool> PreventExtensions(
      Handle<JSProxy> proxy, ShouldThrow should_throw);

  // ES6 9.5.5
  V8_WARN_UNUSED_RESULT static Maybe<bool> GetOwnPropertyDescriptor(
      Isolate* isolate, Handle<JSProxy> proxy, Handle<Name> name,
      PropertyDescriptor* desc);

  // ES6 9.5.6
  V8_WARN_UNUSED_RESULT static Maybe<bool> DefineOwnProperty(
      Isolate* isolate, Handle<JSProxy> object, Handle<Object> key,
      PropertyDescriptor* desc, ShouldThrow should_throw);

  // ES6 9.5.7
  V8_WARN_UNUSED_RESULT static Maybe<bool> HasProperty(Isolate* isolate,
                                                       Handle<JSProxy> proxy,
                                                       Handle<Name> name);

  // This function never returns false.
  // It returns either true or throws.
  V8_WARN_UNUSED_RESULT static Maybe<bool> CheckHasTrap(
      Isolate* isolate, Handle<Name> name, Handle<JSReceiver> target);

  // ES6 9.5.8
  V8_WARN_UNUSED_RESULT static MaybeHandle<Object> GetProperty(
      Isolate* isolate, Handle<JSProxy> proxy, Handle<Name> name,
      Handle<Object> receiver, bool* was_found);

  enum AccessKind { kGet, kSet };

  static MaybeHandle<Object> CheckGetSetTrapResult(Isolate* isolate,
                                                   Handle<Name> name,
                                                   Handle<JSReceiver> target,
                                                   Handle<Object> trap_result,
                                                   AccessKind access_kind);

  // ES6 9.5.9
  V8_WARN_UNUSED_RESULT static Maybe<bool> SetProperty(
      Handle<JSProxy> proxy, Handle<Name> name, Handle<Object> value,
      Handle<Object> receiver, LanguageMode language_mode);

  // ES6 9.5.10 (when passed LanguageMode::kSloppy)
  V8_WARN_UNUSED_RESULT static Maybe<bool> DeletePropertyOrElement(
      Handle<JSProxy> proxy, Handle<Name> name, LanguageMode language_mode);

  // ES6 9.5.12
  V8_WARN_UNUSED_RESULT static Maybe<bool> OwnPropertyKeys(
      Isolate* isolate, Handle<JSReceiver> receiver, Handle<JSProxy> proxy,
      PropertyFilter filter, KeyAccumulator* accumulator);

  V8_WARN_UNUSED_RESULT static Maybe<PropertyAttributes> GetPropertyAttributes(
      LookupIterator* it);

  // Dispatched behavior.
  DECL_PRINTER(JSProxy)
  DECL_VERIFIER(JSProxy)

  static const int kMaxIterationLimit = 100 * 1024;

  // Layout description.
#define JS_PROXY_FIELDS(V)       \
  V(kTargetOffset, kTaggedSize)  \
  V(kHandlerOffset, kTaggedSize) \
  /* Total size. */              \
  V(kSize, 0)

  DEFINE_FIELD_OFFSET_CONSTANTS(JSReceiver::kHeaderSize, JS_PROXY_FIELDS)
#undef JS_PROXY_FIELDS

  // kTargetOffset aliases with the elements of JSObject. The fact that
  // JSProxy::target is a Javascript value which cannot be confused with an
  // elements backing store is exploited by loading from this offset from an
  // unknown JSReceiver.
  STATIC_ASSERT(static_cast<int>(JSObject::kElementsOffset) ==
                static_cast<int>(JSProxy::kTargetOffset));

  typedef FixedBodyDescriptor<JSReceiver::kPropertiesOrHashOffset, kSize, kSize>
      BodyDescriptor;

  static Maybe<bool> SetPrivateSymbol(Isolate* isolate, Handle<JSProxy> proxy,
                                      Handle<Symbol> private_name,
                                      PropertyDescriptor* desc,
                                      ShouldThrow should_throw);

  OBJECT_CONSTRUCTORS(JSProxy, JSReceiver);
};

// JSProxyRevocableResult is just a JSObject with a specific initial map.
// This initial map adds in-object properties for "proxy" and "revoke".
// See https://tc39.github.io/ecma262/#sec-proxy.revocable
class JSProxyRevocableResult : public JSObject {
 public:
  // Layout description.
#define JS_PROXY_REVOCATABLE_RESULT_FIELDS(V) \
  V(kProxyOffset, kTaggedSize)                \
  V(kRevokeOffset, kTaggedSize)               \
  /* Total size. */                           \
  V(kSize, 0)

  DEFINE_FIELD_OFFSET_CONSTANTS(JSObject::kHeaderSize,
                                JS_PROXY_REVOCATABLE_RESULT_FIELDS)
#undef JS_PROXY_REVOCATABLE_RESULT_FIELDS

  // Indices of in-object properties.
  static const int kProxyIndex = 0;
  static const int kRevokeIndex = 1;

 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(JSProxyRevocableResult);
};

}  // namespace internal
}  // namespace v8

#include "src/objects/object-macros-undef.h"

#endif  // V8_OBJECTS_JS_PROXY_H_