/* -*- 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/. */

#include "nsStringEnumerator.h"
#include "nsISimpleEnumerator.h"
#include "nsSupportsPrimitives.h"
#include "mozilla/Attributes.h"
#include "nsTArray.h"

//
// nsStringEnumerator
//

class nsStringEnumerator final : public nsIStringEnumerator,
                                 public nsIUTF8StringEnumerator,
                                 public nsISimpleEnumerator {
 public:
  nsStringEnumerator(const nsTArray<nsString>* aArray, bool aOwnsArray)
      : mArray(aArray), mIndex(0), mOwnsArray(aOwnsArray), mIsUnicode(true) {}

  nsStringEnumerator(const nsTArray<nsCString>* aArray, bool aOwnsArray)
      : mCArray(aArray), mIndex(0), mOwnsArray(aOwnsArray), mIsUnicode(false) {}

  nsStringEnumerator(const nsTArray<nsString>* aArray, nsISupports* aOwner)
      : mArray(aArray),
        mIndex(0),
        mOwner(aOwner),
        mOwnsArray(false),
        mIsUnicode(true) {}

  nsStringEnumerator(const nsTArray<nsCString>* aArray, nsISupports* aOwner)
      : mCArray(aArray),
        mIndex(0),
        mOwner(aOwner),
        mOwnsArray(false),
        mIsUnicode(false) {}

  NS_DECL_ISUPPORTS
  NS_DECL_NSIUTF8STRINGENUMERATOR

  // have to declare nsIStringEnumerator manually, because of
  // overlapping method names
  NS_IMETHOD GetNext(nsAString& aResult) override;
  NS_DECL_NSISIMPLEENUMERATOR

 private:
  ~nsStringEnumerator() {
    if (mOwnsArray) {
      // const-casting is safe here, because the NS_New*
      // constructors make sure mOwnsArray is consistent with
      // the constness of the objects
      if (mIsUnicode) {
        delete const_cast<nsTArray<nsString>*>(mArray);
      } else {
        delete const_cast<nsTArray<nsCString>*>(mCArray);
      }
    }
  }

  union {
    const nsTArray<nsString>* mArray;
    const nsTArray<nsCString>* mCArray;
  };

  inline uint32_t Count() {
    return mIsUnicode ? mArray->Length() : mCArray->Length();
  }

  uint32_t mIndex;

  // the owner allows us to hold a strong reference to the object
  // that owns the array. Having a non-null value in mOwner implies
  // that mOwnsArray is false, because we rely on the real owner
  // to release the array
  nsCOMPtr<nsISupports> mOwner;
  bool mOwnsArray;
  bool mIsUnicode;
};

NS_IMPL_ISUPPORTS(nsStringEnumerator, nsIStringEnumerator,
                  nsIUTF8StringEnumerator, nsISimpleEnumerator)

NS_IMETHODIMP
nsStringEnumerator::HasMore(bool* aResult) {
  *aResult = mIndex < Count();
  return NS_OK;
}

NS_IMETHODIMP
nsStringEnumerator::HasMoreElements(bool* aResult) { return HasMore(aResult); }

NS_IMETHODIMP
nsStringEnumerator::GetNext(nsISupports** aResult) {
  if (mIsUnicode) {
    nsSupportsString* stringImpl = new nsSupportsString();
    if (!stringImpl) {
      return NS_ERROR_OUT_OF_MEMORY;
    }

    stringImpl->SetData(mArray->ElementAt(mIndex++));
    *aResult = stringImpl;
  } else {
    nsSupportsCString* cstringImpl = new nsSupportsCString();
    if (!cstringImpl) {
      return NS_ERROR_OUT_OF_MEMORY;
    }

    cstringImpl->SetData(mCArray->ElementAt(mIndex++));
    *aResult = cstringImpl;
  }
  NS_ADDREF(*aResult);
  return NS_OK;
}

NS_IMETHODIMP
nsStringEnumerator::GetNext(nsAString& aResult) {
  if (NS_WARN_IF(mIndex >= Count())) {
    return NS_ERROR_UNEXPECTED;
  }

  if (mIsUnicode) {
    aResult = mArray->ElementAt(mIndex++);
  } else {
    CopyUTF8toUTF16(mCArray->ElementAt(mIndex++), aResult);
  }

  return NS_OK;
}

NS_IMETHODIMP
nsStringEnumerator::GetNext(nsACString& aResult) {
  if (NS_WARN_IF(mIndex >= Count())) {
    return NS_ERROR_UNEXPECTED;
  }

  if (mIsUnicode) {
    CopyUTF16toUTF8(mArray->ElementAt(mIndex++), aResult);
  } else {
    aResult = mCArray->ElementAt(mIndex++);
  }

  return NS_OK;
}

template <class T>
static inline nsresult StringEnumeratorTail(T** aResult) {
  if (!*aResult) {
    return NS_ERROR_OUT_OF_MEMORY;
  }
  NS_ADDREF(*aResult);
  return NS_OK;
}

//
// constructors
//

nsresult NS_NewStringEnumerator(nsIStringEnumerator** aResult,
                                const nsTArray<nsString>* aArray,
                                nsISupports* aOwner) {
  if (NS_WARN_IF(!aResult) || NS_WARN_IF(!aArray)) {
    return NS_ERROR_INVALID_ARG;
  }

  *aResult = new nsStringEnumerator(aArray, aOwner);
  return StringEnumeratorTail(aResult);
}

nsresult NS_NewUTF8StringEnumerator(nsIUTF8StringEnumerator** aResult,
                                    const nsTArray<nsCString>* aArray,
                                    nsISupports* aOwner) {
  if (NS_WARN_IF(!aResult) || NS_WARN_IF(!aArray)) {
    return NS_ERROR_INVALID_ARG;
  }

  *aResult = new nsStringEnumerator(aArray, aOwner);
  return StringEnumeratorTail(aResult);
}

nsresult NS_NewAdoptingStringEnumerator(nsIStringEnumerator** aResult,
                                        nsTArray<nsString>* aArray) {
  if (NS_WARN_IF(!aResult) || NS_WARN_IF(!aArray)) {
    return NS_ERROR_INVALID_ARG;
  }

  *aResult = new nsStringEnumerator(aArray, true);
  return StringEnumeratorTail(aResult);
}

nsresult NS_NewAdoptingUTF8StringEnumerator(nsIUTF8StringEnumerator** aResult,
                                            nsTArray<nsCString>* aArray) {
  if (NS_WARN_IF(!aResult) || NS_WARN_IF(!aArray)) {
    return NS_ERROR_INVALID_ARG;
  }

  *aResult = new nsStringEnumerator(aArray, true);
  return StringEnumeratorTail(aResult);
}

// const ones internally just forward to the non-const equivalents
nsresult NS_NewStringEnumerator(nsIStringEnumerator** aResult,
                                const nsTArray<nsString>* aArray) {
  if (NS_WARN_IF(!aResult) || NS_WARN_IF(!aArray)) {
    return NS_ERROR_INVALID_ARG;
  }

  *aResult = new nsStringEnumerator(aArray, false);
  return StringEnumeratorTail(aResult);
}

nsresult NS_NewUTF8StringEnumerator(nsIUTF8StringEnumerator** aResult,
                                    const nsTArray<nsCString>* aArray) {
  if (NS_WARN_IF(!aResult) || NS_WARN_IF(!aArray)) {
    return NS_ERROR_INVALID_ARG;
  }

  *aResult = new nsStringEnumerator(aArray, false);
  return StringEnumeratorTail(aResult);
}