nsStringEnumerator.h

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/* -*- 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 nsStringEnumerator_h

#define nsStringEnumerator_h

#include "nsIStringEnumerator.h"

#include "nsStringFwd.h"

#include "nsTArrayForwardDeclare.h"

class nsStringEnumeratorBase : public nsIStringEnumerator,

                               public nsIUTF8StringEnumerator {

 public:

  NS_DECL_NSISTRINGENUMERATORBASE

  NS_IMETHOD GetNext(nsAString&) override;

  using nsIUTF8StringEnumerator::GetNext;

 protected:

  virtual ~nsStringEnumeratorBase() = default;

};

// nsIStringEnumerator/nsIUTF8StringEnumerator implementations

//

// Currently all implementations support both interfaces. The

// constructors below provide the most common interface for the given

// type (i.e. nsIStringEnumerator for char16_t* strings, and so

// forth) but any resulting enumerators can be queried to the other

// type. Internally, the enumerators will hold onto the type that was

// passed in and do conversion if GetNext() for the other type of

// string is called.

// There are a few different types of enumerators:

//

// These enumerators hold a pointer to the array. Be careful

// because modifying the array may confuse the iterator, especially if

// you insert or remove elements in the middle of the array.

//

// The non-adopting enumerator requires that the array sticks around

// at least as long as the enumerator does. These are for constant

// string arrays that the enumerator does not own, this could be used

// in VERY specialized cases such as when the provider KNOWS that the

// string enumerator will be consumed immediately, or will at least

// outlast the array.

// For example:

//

// nsTArray<nsCString> array;

// array.AppendCString("abc");

// array.AppendCString("def");

// NS_NewStringEnumerator(&enumerator, &array, true);

//

// // call some internal method which iterates the enumerator

// InternalMethod(enumerator);

// NS_RELEASE(enumerator);

//

[[nodiscard]] nsresult NS_NewStringEnumerator(nsIStringEnumerator** aResult,

                                              const nsTArray<nsString>* aArray,

                                              nsISupports* aOwner);

[[nodiscard]] nsresult NS_NewUTF8StringEnumerator(

    nsIUTF8StringEnumerator** aResult, const nsTArray<nsCString>* aArray);

[[nodiscard]] nsresult NS_NewStringEnumerator(nsIStringEnumerator** aResult,

                                              const nsTArray<nsString>* aArray);

// Adopting string enumerators assume ownership of the array and will

// call |operator delete| on the array when the enumerator is destroyed

// this is useful when the provider creates an array solely for the

// purpose of creating the enumerator.

// For example:

//

// nsTArray<nsCString>* array = new nsTArray<nsCString>;

// array->AppendString("abcd");

// NS_NewAdoptingStringEnumerator(&result, array);

[[nodiscard]] nsresult NS_NewAdoptingStringEnumerator(

    nsIStringEnumerator** aResult, nsTArray<nsString>* aArray);

[[nodiscard]] nsresult NS_NewAdoptingUTF8StringEnumerator(

    nsIUTF8StringEnumerator** aResult, nsTArray<nsCString>* aArray);

// these versions take a refcounted "owner" which will be addreffed

// when the enumerator is created, and destroyed when the enumerator

// is released. This allows providers to give non-owning pointers to

// ns*StringArray member variables without worrying about lifetime

// issues

// For example:

//

// nsresult MyClass::Enumerate(nsIUTF8StringEnumerator** aResult) {

//     mCategoryList->AppendString("abcd");

//     return NS_NewStringEnumerator(aResult, mCategoryList, this);

// }

//

[[nodiscard]] nsresult NS_NewUTF8StringEnumerator(

    nsIUTF8StringEnumerator** aResult, const nsTArray<nsCString>* aArray,

    nsISupports* aOwner);

#endif  // defined nsStringEnumerator_h