/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 AddonManagerStartup_inlines_h
#define AddonManagerStartup_inlines_h

#include <utility>

#include "js/Array.h"  // JS::GetArrayLength, JS::IsArrayObject
#include "js/Exception.h"
#include "js/PropertyAndElement.h"  // JS_Enumerate, JS_GetElement, JS_GetProperty, JS_GetPropertyById
#include "jsapi.h"
#include "mozilla/Maybe.h"
#include "nsJSUtils.h"

namespace mozilla {

class ArrayIterElem;
class PropertyIterElem;

/*****************************************************************************
 * Object iterator base classes
 *****************************************************************************/

template <class T, class PropertyType>
class MOZ_STACK_CLASS BaseIter {
 public:
  typedef T SelfType;

  PropertyType begin() const { return PropertyType(Self()); }

  PropertyType end() const {
    PropertyType elem(Self());
    return elem.End();
  }

  void* Context() const { return mContext; }

 protected:
  BaseIter(JSContext* cx, JS::Handle<JSObject*> object, void* context = nullptr)
      : mCx(cx), mObject(object), mContext(context) {}

  const SelfType& Self() const { return *static_cast<const SelfType*>(this); }
  SelfType& Self() { return *static_cast<SelfType*>(this); }

  JSContext* mCx;

  JS::Handle<JSObject*> mObject;

  void* mContext;
};

template <class T, class IterType>
class MOZ_STACK_CLASS BaseIterElem {
 public:
  typedef T SelfType;

  explicit BaseIterElem(const IterType& iter, uint32_t index = 0)
      : mIter(iter), mIndex(index) {}

  uint32_t Length() const { return mIter.Length(); }

  JS::Value Value() {
    JS::Rooted<JS::Value> value(mIter.mCx, JS::UndefinedValue());

    auto& self = Self();
    if (!self.GetValue(&value)) {
      JS_ClearPendingException(mIter.mCx);
    }

    return value;
  }

  SelfType& operator*() { return Self(); }

  SelfType& operator++() {
    MOZ_ASSERT(mIndex < Length());
    mIndex++;
    return Self();
  }

  bool operator!=(const SelfType& other) const {
    return &mIter != &other.mIter || mIndex != other.mIndex;
  }

  SelfType End() const {
    SelfType end(mIter);
    end.mIndex = Length();
    return end;
  }

  void* Context() const { return mIter.Context(); }

 protected:
  const SelfType& Self() const { return *static_cast<const SelfType*>(this); }
  SelfType& Self() { return *static_cast<SelfType*>(this); }

  const IterType& mIter;

  uint32_t mIndex;
};

/*****************************************************************************
 * Property iteration
 *****************************************************************************/

class MOZ_STACK_CLASS PropertyIter
    : public BaseIter<PropertyIter, PropertyIterElem> {
  friend class PropertyIterElem;
  friend class BaseIterElem<PropertyIterElem, PropertyIter>;

 public:
  PropertyIter(JSContext* cx, JS::Handle<JSObject*> object,
               void* context = nullptr)
      : BaseIter(cx, object, context), mIds(cx, JS::IdVector(cx)) {
    if (!JS_Enumerate(cx, object, &mIds)) {
      JS_ClearPendingException(cx);
    }
  }

  PropertyIter(const PropertyIter& other)
      : PropertyIter(other.mCx, other.mObject, other.mContext) {}

  PropertyIter& operator=(const PropertyIter& other) {
    MOZ_ASSERT(other.mObject == mObject);
    mCx = other.mCx;
    mContext = other.mContext;

    mIds.clear();
    if (!JS_Enumerate(mCx, mObject, &mIds)) {
      JS_ClearPendingException(mCx);
    }
    return *this;
  }

  int32_t Length() const { return mIds.length(); }

 protected:
  JS::Rooted<JS::IdVector> mIds;
};

class MOZ_STACK_CLASS PropertyIterElem
    : public BaseIterElem<PropertyIterElem, PropertyIter> {
  friend class BaseIterElem<PropertyIterElem, PropertyIter>;

 public:
  using BaseIterElem::BaseIterElem;

  PropertyIterElem(const PropertyIterElem& other)
      : BaseIterElem(other.mIter, other.mIndex) {}

  jsid Id() {
    MOZ_ASSERT(mIndex < mIter.mIds.length());

    return mIter.mIds[mIndex];
  }

  const nsAString& Name() {
    if (mName.isNothing()) {
      mName.emplace();
      mName.ref().init(mIter.mCx, Id());
    }
    return mName.ref();
  }

  JSContext* Cx() { return mIter.mCx; }

 protected:
  bool GetValue(JS::MutableHandle<JS::Value> value) {
    MOZ_ASSERT(mIndex < Length());
    JS::Rooted<jsid> id(mIter.mCx, Id());

    return JS_GetPropertyById(mIter.mCx, mIter.mObject, id, value);
  }

 private:
  Maybe<nsAutoJSString> mName;
};

/*****************************************************************************
 * Array iteration
 *****************************************************************************/

class MOZ_STACK_CLASS ArrayIter : public BaseIter<ArrayIter, ArrayIterElem> {
  friend class ArrayIterElem;
  friend class BaseIterElem<ArrayIterElem, ArrayIter>;

 public:
  ArrayIter(JSContext* cx, JS::Handle<JSObject*> object)
      : BaseIter(cx, object), mLength(0) {
    bool isArray;
    if (!JS::IsArrayObject(cx, object, &isArray) || !isArray) {
      JS_ClearPendingException(cx);
      return;
    }

    if (!JS::GetArrayLength(cx, object, &mLength)) {
      JS_ClearPendingException(cx);
    }
  }

  uint32_t Length() const { return mLength; }

 private:
  uint32_t mLength;
};

class MOZ_STACK_CLASS ArrayIterElem
    : public BaseIterElem<ArrayIterElem, ArrayIter> {
  friend class BaseIterElem<ArrayIterElem, ArrayIter>;

 public:
  using BaseIterElem::BaseIterElem;

  ArrayIterElem(const ArrayIterElem& other)
      : BaseIterElem(other.mIter, other.mIndex) {}

 protected:
  bool GetValue(JS::MutableHandle<JS::Value> value) {
    MOZ_ASSERT(mIndex < Length());
    return JS_GetElement(mIter.mCx, mIter.mObject, mIndex, value);
  }
};

}  // namespace mozilla

#endif  // AddonManagerStartup_inlines_h
