// 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_VALUE_H_

#define INCLUDE_V8_VALUE_H_

#include "v8-data.h"          // NOLINT(build/include_directory)

#include "v8-internal.h"      // NOLINT(build/include_directory)

#include "v8-local-handle.h"  // NOLINT(build/include_directory)

#include "v8-maybe.h"         // NOLINT(build/include_directory)

#include "v8config.h"         // NOLINT(build/include_directory)

/**

 * The v8 JavaScript engine.

 */

namespace v8 {

class Primitive;

class Numeric;

class BigInt;

class Int32;

class Integer;

class Number;

class Object;

class String;

class Uint32;

/**

 * The superclass of all JavaScript values and objects.

 */

class V8_EXPORT Value : public Data {

 public:

  /**

   * Returns true if this value is the undefined value.  See ECMA-262

   * 4.3.10.

   *

   * This is equivalent to `value === undefined` in JS.

   */

  V8_INLINE bool IsUndefined() const;

  /**

   * Returns true if this value is the null value.  See ECMA-262

   * 4.3.11.

   *

   * This is equivalent to `value === null` in JS.

   */

  V8_INLINE bool IsNull() const;

  /**

   * Returns true if this value is either the null or the undefined value.

   * See ECMA-262

   * 4.3.11. and 4.3.12

   *

   * This is equivalent to `value == null` in JS.

   */

  V8_INLINE bool IsNullOrUndefined() const;

  /**

   * Returns true if this value is true.

   *

   * This is not the same as `BooleanValue()`. The latter performs a

   * conversion to boolean, i.e. the result of `Boolean(value)` in JS, whereas

   * this checks `value === true`.

   */

  V8_INLINE bool IsTrue() const;

  /**

   * Returns true if this value is false.

   *

   * This is not the same as `!BooleanValue()`. The latter performs a

   * conversion to boolean, i.e. the result of `!Boolean(value)` in JS, whereas

   * this checks `value === false`.

   */

  V8_INLINE bool IsFalse() const;

  /**

   * Returns true if this value is a symbol or a string.

   *

   * This is equivalent to

   * `typeof value === 'string' || typeof value === 'symbol'` in JS.

   */

  bool IsName() const;

  /**

   * Returns true if this value is an instance of the String type.

   * See ECMA-262 8.4.

   *

   * This is equivalent to `typeof value === 'string'` in JS.

   */

  V8_INLINE bool IsString() const;

  /**

   * Returns true if this value is a symbol.

   *

   * This is equivalent to `typeof value === 'symbol'` in JS.

   */

  bool IsSymbol() const;

  /**

   * Returns true if this value is a function.

   *

   * This is equivalent to `typeof value === 'function'` in JS.

   */

  bool IsFunction() const;

  /**

   * Returns true if this value is an array. Note that it will return false for

   * an Proxy for an array.

   */

  bool IsArray() const;

  /**

   * Returns true if this value is an object.

   */

  bool IsObject() const;

  /**

   * Returns true if this value is a bigint.

   *

   * This is equivalent to `typeof value === 'bigint'` in JS.

   */

  bool IsBigInt() const;

  /**

   * Returns true if this value is boolean.

   *

   * This is equivalent to `typeof value === 'boolean'` in JS.

   */

  bool IsBoolean() const;

  /**

   * Returns true if this value is a number.

   *

   * This is equivalent to `typeof value === 'number'` in JS.

   */

  bool IsNumber() const;

  /**

   * Returns true if this value is an `External` object.

   */

  bool IsExternal() const;

  /**

   * Returns true if this value is a 32-bit signed integer.

   */

  bool IsInt32() const;

  /**

   * Returns true if this value is a 32-bit unsigned integer.

   */

  bool IsUint32() const;

  /**

   * Returns true if this value is a Date.

   */

  bool IsDate() const;

  /**

   * Returns true if this value is an Arguments object.

   */

  bool IsArgumentsObject() const;

  /**

   * Returns true if this value is a BigInt object.

   */

  bool IsBigIntObject() const;

  /**

   * Returns true if this value is a Boolean object.

   */

  bool IsBooleanObject() const;

  /**

   * Returns true if this value is a Number object.

   */

  bool IsNumberObject() const;

  /**

   * Returns true if this value is a String object.

   */

  bool IsStringObject() const;

  /**

   * Returns true if this value is a Symbol object.

   */

  bool IsSymbolObject() const;

  /**

   * Returns true if this value is a NativeError.

   */

  bool IsNativeError() const;

  /**

   * Returns true if this value is a RegExp.

   */

  bool IsRegExp() const;

  /**

   * Returns true if this value is an async function.

   */

  bool IsAsyncFunction() const;

  /**

   * Returns true if this value is a Generator function.

   */

  bool IsGeneratorFunction() const;

  /**

   * Returns true if this value is a Generator object (iterator).

   */

  bool IsGeneratorObject() const;

  /**

   * Returns true if this value is a Promise.

   */

  bool IsPromise() const;

  /**

   * Returns true if this value is a Map.

   */

  bool IsMap() const;

  /**

   * Returns true if this value is a Set.

   */

  bool IsSet() const;

  /**

   * Returns true if this value is a Map Iterator.

   */

  bool IsMapIterator() const;

  /**

   * Returns true if this value is a Set Iterator.

   */

  bool IsSetIterator() const;

  /**

   * Returns true if this value is a WeakMap.

   */

  bool IsWeakMap() const;

  /**

   * Returns true if this value is a WeakSet.

   */

  bool IsWeakSet() const;

  /**

   * Returns true if this value is a WeakRef.

   */

  bool IsWeakRef() const;

  /**

   * Returns true if this value is an ArrayBuffer.

   */

  bool IsArrayBuffer() const;

  /**

   * Returns true if this value is an ArrayBufferView.

   */

  bool IsArrayBufferView() const;

  /**

   * Returns true if this value is one of TypedArrays.

   */

  bool IsTypedArray() const;

  /**

   * Returns true if this value is an Uint8Array.

   */

  bool IsUint8Array() const;

  /**

   * Returns true if this value is an Uint8ClampedArray.

   */

  bool IsUint8ClampedArray() const;

  /**

   * Returns true if this value is an Int8Array.

   */

  bool IsInt8Array() const;

  /**

   * Returns true if this value is an Uint16Array.

   */

  bool IsUint16Array() const;

  /**

   * Returns true if this value is an Int16Array.

   */

  bool IsInt16Array() const;

  /**

   * Returns true if this value is an Uint32Array.

   */

  bool IsUint32Array() const;

  /**

   * Returns true if this value is an Int32Array.

   */

  bool IsInt32Array() const;

  /**

   * Returns true if this value is a Float16Array.

   */

  bool IsFloat16Array() const;

  /**

   * Returns true if this value is a Float32Array.

   */

  bool IsFloat32Array() const;

  /**

   * Returns true if this value is a Float64Array.

   */

  bool IsFloat64Array() const;

  /**

   * Returns true if this value is a BigInt64Array.

   */

  bool IsBigInt64Array() const;

  /**

   * Returns true if this value is a BigUint64Array.

   */

  bool IsBigUint64Array() const;

  /**

   * Returns true if this value is a DataView.

   */

  bool IsDataView() const;

  /**

   * Returns true if this value is a SharedArrayBuffer.

   */

  bool IsSharedArrayBuffer() const;

  /**

   * Returns true if this value is a JavaScript Proxy.

   */

  bool IsProxy() const;

  /**

   * Returns true if this value is a WasmMemoryObject.

   */

  bool IsWasmMemoryObject() const;

  /**

   * Returns true if this value is a WasmMemoryMapDescriptor.

   */

  bool IsWasmMemoryMapDescriptor() const;

  /**

   * Returns true if this value is a WasmModuleObject.

   */

  bool IsWasmModuleObject() const;

  /**

   * Returns true if this value is the WasmNull object.

   */

  bool IsWasmNull() const;

  /**

   * Returns true if the value is a Module Namespace Object.

   */

  bool IsModuleNamespaceObject() const;

  /**

   * Returns true if the value is a primitive.

   */

  bool IsPrimitive() const;

  /**

   * Perform `ToPrimitive(value)` as specified in:

   * https://tc39.es/ecma262/#sec-toprimitive.

   */

  V8_WARN_UNUSED_RESULT MaybeLocal<Primitive> ToPrimitive(

      Local<Context> context) const;

  /**

   * Perform `ToNumeric(value)` as specified in:

   * https://tc39.es/ecma262/#sec-tonumeric.

   */

  V8_WARN_UNUSED_RESULT MaybeLocal<Numeric> ToNumeric(

      Local<Context> context) const;

  /**

   * Perform the equivalent of `BigInt(value)` in JS.

   */

  V8_WARN_UNUSED_RESULT MaybeLocal<BigInt> ToBigInt(

      Local<Context> context) const;

  /**

   * Perform the equivalent of `Number(value)` in JS.

   */

  V8_WARN_UNUSED_RESULT MaybeLocal<Number> ToNumber(

      Local<Context> context) const;

  /**

   * Perform the equivalent of `String(value)` in JS.

   */

  V8_WARN_UNUSED_RESULT MaybeLocal<String> ToString(

      Local<Context> context) const;

  /**

   * Provide a string representation of this value usable for debugging.

   * This operation has no observable side effects and will succeed

   * unless e.g. execution is being terminated.

   */

  V8_WARN_UNUSED_RESULT MaybeLocal<String> ToDetailString(

      Local<Context> context) const;

  /**

   * Perform the equivalent of `Tagged<Object>(value)` in JS.

   */

  V8_WARN_UNUSED_RESULT MaybeLocal<Object> ToObject(

      Local<Context> context) const;

  /**

   * Perform the equivalent of `Number(value)` in JS and convert the result

   * to an integer. Negative values are rounded up, positive values are rounded

   * down. NaN is converted to 0. Infinite values yield undefined results.

   */

  V8_WARN_UNUSED_RESULT MaybeLocal<Integer> ToInteger(

      Local<Context> context) const;

  /**

   * Perform the equivalent of `Number(value)` in JS and convert the result

   * to an unsigned 32-bit integer by performing the steps in

   * https://tc39.es/ecma262/#sec-touint32.

   */

  V8_WARN_UNUSED_RESULT MaybeLocal<Uint32> ToUint32(

      Local<Context> context) const;

  /**

   * Perform the equivalent of `Number(value)` in JS and convert the result

   * to a signed 32-bit integer by performing the steps in

   * https://tc39.es/ecma262/#sec-toint32.

   */

  V8_WARN_UNUSED_RESULT MaybeLocal<Int32> ToInt32(Local<Context> context) const;

  /**

   * Perform the equivalent of `Boolean(value)` in JS. This can never fail.

   */

  Local<Boolean> ToBoolean(Isolate* isolate) const;

  /**

   * Attempts to convert a string to an array index.

   * Returns an empty handle if the conversion fails.

   */

  V8_WARN_UNUSED_RESULT MaybeLocal<Uint32> ToArrayIndex(

      Local<Context> context) const;

  /** Returns the equivalent of `ToBoolean()->Value()`. */

  bool BooleanValue(Isolate* isolate) const;

  /** Returns the equivalent of `ToNumber()->Value()`. */

  V8_WARN_UNUSED_RESULT Maybe<double> NumberValue(Local<Context> context) const;

  /** Returns the equivalent of `ToInteger()->Value()`. */

  V8_WARN_UNUSED_RESULT Maybe<int64_t> IntegerValue(

      Local<Context> context) const;

  /** Returns the equivalent of `ToUint32()->Value()`. */

  V8_WARN_UNUSED_RESULT Maybe<uint32_t> Uint32Value(

      Local<Context> context) const;

  /** Returns the equivalent of `ToInt32()->Value()`. */

  V8_WARN_UNUSED_RESULT Maybe<int32_t> Int32Value(Local<Context> context) const;

  /** JS == */

  V8_WARN_UNUSED_RESULT Maybe<bool> Equals(Local<Context> context,

                                           Local<Value> that) const;

  bool StrictEquals(Local<Value> that) const;

  bool SameValue(Local<Value> that) const;

  template <class T>

  V8_INLINE static Value* Cast(T* value) {

    return static_cast<Value*>(value);

  }

  Local<String> TypeOf(Isolate*);

  Maybe<bool> InstanceOf(Local<Context> context, Local<Object> object);

  /**

   * Get the hash of this value. The hash is not guaranteed to be

   * unique. For |Object| and |Name| instances the result is equal to

   * |GetIdentityHash|. Hashes are not guaranteed to be stable across

   * different isolates or processes.

   */

  uint32_t GetHash();

 private:

  V8_INLINE bool QuickIsUndefined() const;

  V8_INLINE bool QuickIsNull() const;

  V8_INLINE bool QuickIsNullOrUndefined() const;

#if V8_STATIC_ROOTS_BOOL

  V8_INLINE bool QuickIsTrue() const;

  V8_INLINE bool QuickIsFalse() const;

#endif  // V8_STATIC_ROOTS_BOOL

  V8_INLINE bool QuickIsString() const;

  bool FullIsUndefined() const;

  bool FullIsNull() const;

  bool FullIsTrue() const;

  bool FullIsFalse() const;

  bool FullIsString() const;

  static void CheckCast(Data* that);

};

/**

 * Can be used to avoid repeated expensive type checks for groups of objects

 * that are expected to be similar (e.g. when Blink converts a bunch of

 * JavaScript objects to "ScriptWrappable" after a "HasInstance" check) by

 * making use of V8-internal "hidden classes". An object that has passed the

 * full check can be remembered via {Update}; further objects can be queried

 * using {Matches}.

 * Note that the answer will be conservative/"best-effort": when {Matches}

 * returns true, then the {candidate} can be relied upon to have the same

 * shape/constructor/prototype/etc. as the {baseline}. Otherwise, no reliable

 * statement can be made (the objects might still have indistinguishable shapes

 * for all intents and purposes, but this mechanism, being optimized for speed,

 * couldn't determine that quickly).

 */

class V8_EXPORT TypecheckWitness {

 public:

  explicit TypecheckWitness(Isolate* isolate);

  /**

   * Checks whether {candidate} can cheaply be identified as being "similar"

   * to the {baseline} that was passed to {Update} earlier.

   * It's safe to call this on an uninitialized {TypecheckWitness} instance:

   * it will then return {false} for any input.

   */

  V8_INLINE bool Matches(Local<Value> candidate) const;

  /**

   * Remembers a new baseline for future {Matches} queries.

   */

  void Update(Local<Value> baseline);

 private:

  Local<Data> cached_map_;

};

template <>

V8_INLINE Value* Value::Cast(Data* value) {

#ifdef V8_ENABLE_CHECKS

  CheckCast(value);

#endif

  return static_cast<Value*>(value);

}

bool Value::IsUndefined() const {

#ifdef V8_ENABLE_CHECKS

  return FullIsUndefined();

#else

  return QuickIsUndefined();

#endif

}

bool Value::QuickIsUndefined() const {

  using A = internal::Address;

  using I = internal::Internals;

  A obj = internal::ValueHelper::ValueAsAddress(this);

#if V8_STATIC_ROOTS_BOOL

  return I::is_identical(obj, I::StaticReadOnlyRoot::kUndefinedValue);

#else

  if (!I::HasHeapObjectTag(obj)) return false;

  if (I::GetInstanceType(obj) != I::kOddballType) return false;

  return (I::GetOddballKind(obj) == I::kUndefinedOddballKind);

#endif  // V8_STATIC_ROOTS_BOOL

}

bool Value::IsNull() const {

#ifdef V8_ENABLE_CHECKS

  return FullIsNull();

#else

  return QuickIsNull();

#endif

}

bool Value::QuickIsNull() const {

  using A = internal::Address;

  using I = internal::Internals;

  A obj = internal::ValueHelper::ValueAsAddress(this);

#if V8_STATIC_ROOTS_BOOL

  return I::is_identical(obj, I::StaticReadOnlyRoot::kNullValue);

#else

  if (!I::HasHeapObjectTag(obj)) return false;

  if (I::GetInstanceType(obj) != I::kOddballType) return false;

  return (I::GetOddballKind(obj) == I::kNullOddballKind);

#endif  // V8_STATIC_ROOTS_BOOL

}

bool Value::IsNullOrUndefined() const {

#ifdef V8_ENABLE_CHECKS

  return FullIsNull() || FullIsUndefined();

#else

  return QuickIsNullOrUndefined();

#endif

}

bool Value::QuickIsNullOrUndefined() const {

#if V8_STATIC_ROOTS_BOOL

  return QuickIsNull() || QuickIsUndefined();

#else

  using A = internal::Address;

  using I = internal::Internals;

  A obj = internal::ValueHelper::ValueAsAddress(this);

  if (!I::HasHeapObjectTag(obj)) return false;

  if (I::GetInstanceType(obj) != I::kOddballType) return false;

  int kind = I::GetOddballKind(obj);

  return kind == I::kNullOddballKind || kind == I::kUndefinedOddballKind;

#endif  // V8_STATIC_ROOTS_BOOL

}

bool Value::IsTrue() const {

#if V8_STATIC_ROOTS_BOOL && !defined(V8_ENABLE_CHECKS)

  return QuickIsTrue();

#else

  return FullIsTrue();

#endif

}

#if V8_STATIC_ROOTS_BOOL

bool Value::QuickIsTrue() const {

  using A = internal::Address;

  using I = internal::Internals;

  A obj = internal::ValueHelper::ValueAsAddress(this);

  return I::is_identical(obj, I::StaticReadOnlyRoot::kTrueValue);

}

#endif  // V8_STATIC_ROOTS_BOOL

bool Value::IsFalse() const {

#if V8_STATIC_ROOTS_BOOL && !defined(V8_ENABLE_CHECKS)

  return QuickIsFalse();

#else

  return FullIsFalse();

#endif

}

#if V8_STATIC_ROOTS_BOOL

bool Value::QuickIsFalse() const {

  using A = internal::Address;

  using I = internal::Internals;

  A obj = internal::ValueHelper::ValueAsAddress(this);

  return I::is_identical(obj, I::StaticReadOnlyRoot::kFalseValue);

}

#endif  // V8_STATIC_ROOTS_BOOL

bool Value::IsString() const {

#ifdef V8_ENABLE_CHECKS

  return FullIsString();

#else

  return QuickIsString();

#endif

}

bool Value::QuickIsString() const {

  using A = internal::Address;

  using I = internal::Internals;

  A obj = internal::ValueHelper::ValueAsAddress(this);

  if (!I::HasHeapObjectTag(obj)) return false;

#if V8_STATIC_ROOTS_BOOL && !V8_MAP_PACKING

  return I::CheckInstanceMapRange(obj,

                                  I::StaticReadOnlyRoot::kStringMapLowerBound,

                                  I::StaticReadOnlyRoot::kStringMapUpperBound);

#else

  return (I::GetInstanceType(obj) < I::kFirstNonstringType);

#endif  // V8_STATIC_ROOTS_BOOL

}

bool TypecheckWitness::Matches(Local<Value> candidate) const {

  internal::Address obj = internal::ValueHelper::ValueAsAddress(*candidate);

  internal::Address obj_map = internal::Internals::LoadMap(obj);

  internal::Address cached =

      internal::ValueHelper::ValueAsAddress(*cached_map_);

  return obj_map == cached;

}

}  // namespace v8

#endif  // INCLUDE_V8_VALUE_H_