ErrorObject.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef vm_ErrorObject_h_
#define vm_ErrorObject_h_

#include "mozilla/ArrayUtils.h"

#include "js/UniquePtr.h"
#include "vm/NativeObject.h"
#include "vm/SavedStacks.h"
#include "vm/Shape.h"

namespace js {

/*
 * Initialize the exception constructor/prototype hierarchy.
 */
extern JSObject* InitExceptionClasses(JSContext* cx, HandleObject obj);

class ErrorObject : public NativeObject {
  static JSObject* createProto(JSContext* cx, JSProtoKey key);

  static JSObject* createConstructor(JSContext* cx, JSProtoKey key);

  /* For access to createProto. */
  friend JSObject* js::InitExceptionClasses(JSContext* cx, HandleObject global);

  static bool init(JSContext* cx, Handle<ErrorObject*> obj, JSExnType type,
                   UniquePtr<JSErrorReport> errorReport, HandleString fileName,
                   HandleObject stack, uint32_t lineNumber,
                   uint32_t columnNumber, HandleString message);

  static const ClassSpec classSpecs[JSEXN_ERROR_LIMIT];
  static const Class protoClasses[JSEXN_ERROR_LIMIT];

 protected:
  static const uint32_t EXNTYPE_SLOT = 0;
  static const uint32_t STACK_SLOT = EXNTYPE_SLOT + 1;
  static const uint32_t ERROR_REPORT_SLOT = STACK_SLOT + 1;
  static const uint32_t FILENAME_SLOT = ERROR_REPORT_SLOT + 1;
  static const uint32_t LINENUMBER_SLOT = FILENAME_SLOT + 1;
  static const uint32_t COLUMNNUMBER_SLOT = LINENUMBER_SLOT + 1;
  static const uint32_t MESSAGE_SLOT = COLUMNNUMBER_SLOT + 1;
  static const uint32_t TIME_WARP_SLOT = MESSAGE_SLOT + 1;

  static const uint32_t RESERVED_SLOTS = TIME_WARP_SLOT + 1;

 public:
  static const Class classes[JSEXN_ERROR_LIMIT];

  static const Class* classForType(JSExnType type) {
    MOZ_ASSERT(type < JSEXN_WARN);
    return &classes[type];
  }

  static bool isErrorClass(const Class* clasp) {
    return &classes[0] <= clasp &&
           clasp < &classes[0] + mozilla::ArrayLength(classes);
  }

  // Create an error of the given type corresponding to the provided location
  // info.  If |message| is non-null, then the error will have a .message
  // property with that value; otherwise the error will have no .message
  // property.
  static ErrorObject* create(JSContext* cx, JSExnType type, HandleObject stack,
                             HandleString fileName, uint32_t lineNumber,
                             uint32_t columnNumber,
                             UniquePtr<JSErrorReport> report,
                             HandleString message,
                             HandleObject proto = nullptr);

  /*
   * Assign the initial error shape to the empty object.  (This shape does
   * *not* include .message, which must be added separately if needed; see
   * ErrorObject::init.)
   */
  static Shape* assignInitialShape(JSContext* cx, Handle<ErrorObject*> obj);

  JSExnType type() const {
    return JSExnType(getReservedSlot(EXNTYPE_SLOT).toInt32());
  }

  JSErrorReport* getErrorReport() const {
    const Value& slot = getReservedSlot(ERROR_REPORT_SLOT);
    if (slot.isUndefined()) {
      return nullptr;
    }
    return static_cast<JSErrorReport*>(slot.toPrivate());
  }

  JSErrorReport* getOrCreateErrorReport(JSContext* cx);

  inline JSString* fileName(JSContext* cx) const;
  inline uint32_t lineNumber() const;
  inline uint32_t columnNumber() const;
  inline JSObject* stack() const;
  inline uint64_t timeWarpTarget() const;

  JSString* getMessage() const {
    const HeapSlot& slot = getReservedSlotRef(MESSAGE_SLOT);
    return slot.isString() ? slot.toString() : nullptr;
  }

  // Getter and setter for the Error.prototype.stack accessor.
  static bool getStack(JSContext* cx, unsigned argc, Value* vp);
  static bool getStack_impl(JSContext* cx, const CallArgs& args);
  static bool setStack(JSContext* cx, unsigned argc, Value* vp);
  static bool setStack_impl(JSContext* cx, const CallArgs& args);
};

}  // namespace js

template <>
inline bool JSObject::is<js::ErrorObject>() const {
  return js::ErrorObject::isErrorClass(getClass());
}

#endif  // vm_ErrorObject_h_