gecko-dev/xpcom/ds/ArrayAlgorithm.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 ArrayAlgorithm_h___
#define ArrayAlgorithm_h___
#include "nsTArray.h"
#include "mozilla/Algorithm.h"
#include "mozilla/ResultExtensions.h"
namespace mozilla {
// An algorithm similar to TransformAbortOnErr, which creates a new nsTArray
// rather than inserting into an output iterator. The capacity of the result
// array is set to the number of elements that will be inserted if all
// transformations are successful. This variant is fallible, i.e. if setting the
// capacity fails, NS_ERROR_OUT_OF_MEMORY is returned as an error value. This
// variant only works with nsresult errors.
template <
typename SrcIter, typename Transform,
typename = std::enable_if_t<std::is_same_v<
typename detail::TransformTraits<Transform, SrcIter>::result_err_type,
nsresult>>>
Result<nsTArray<typename detail::TransformTraits<Transform,
SrcIter>::result_ok_type>,
nsresult>
TransformIntoNewArrayAbortOnErr(SrcIter aIter, SrcIter aEnd,
Transform aTransform, fallible_t) {
nsTArray<typename detail::TransformTraits<Transform, SrcIter>::result_ok_type>
res;
if (!res.SetCapacity(std::distance(aIter, aEnd), fallible)) {
return Err(NS_ERROR_OUT_OF_MEMORY);
}
auto transformRes = TransformAbortOnErr(aIter, aEnd, MakeBackInserter(res),
std::move(aTransform));
if (NS_WARN_IF(transformRes.isErr())) {
return Err(transformRes.unwrapErr());
}
return res;
}
template <typename SrcRange, typename Transform>
auto TransformIntoNewArrayAbortOnErr(SrcRange& aRange, Transform aTransform,
fallible_t) {
using std::begin;
using std::end;
return TransformIntoNewArrayAbortOnErr(begin(aRange), end(aRange), aTransform,
fallible);
}
// An algorithm similar to std::transform, which creates a new nsTArray
// rather than inserting into an output iterator. The capacity of the result
// array is set to the number of elements that will be inserted. This variant is
// fallible, i.e. if setting the capacity fails, NS_ERROR_OUT_OF_MEMORY is
// returned as an error value. This variant only works with nsresult errors.
template <typename SrcIter, typename Transform>
Result<nsTArray<detail::ArrayElementTransformType<Transform, SrcIter>>,
nsresult>
TransformIntoNewArray(SrcIter aIter, SrcIter aEnd, Transform aTransform,
fallible_t) {
nsTArray<detail::ArrayElementTransformType<Transform, SrcIter>> res;
if (!res.SetCapacity(std::distance(aIter, aEnd), fallible)) {
return Err(NS_ERROR_OUT_OF_MEMORY);
}
std::transform(aIter, aEnd, MakeBackInserter(res), std::move(aTransform));
return res;
}
template <typename SrcRange, typename Transform>
auto TransformIntoNewArray(SrcRange& aRange, Transform aTransform, fallible_t) {
using std::begin;
using std::end;
return TransformIntoNewArray(begin(aRange), end(aRange), aTransform,
fallible);
}
// An algorithm similar to std::transform, which creates a new nsTArray
// rather than inserting into an output iterator. The capacity of the result
// array is set to the number of elements that will be inserted. This variant is
// infallible, i.e. if setting the capacity fails, the process is aborted.
template <typename SrcIter, typename Transform>
nsTArray<detail::ArrayElementTransformType<Transform, SrcIter>>
TransformIntoNewArray(SrcIter aIter, SrcIter aEnd, Transform aTransform) {
nsTArray<detail::ArrayElementTransformType<Transform, SrcIter>> res;
res.SetCapacity(std::distance(aIter, aEnd));
std::transform(aIter, aEnd, MakeBackInserter(res), std::move(aTransform));
return res;
}
template <typename SrcRange, typename Transform>
auto TransformIntoNewArray(SrcRange& aRange, Transform aTransform) {
using std::begin;
using std::end;
return TransformIntoNewArray(begin(aRange), end(aRange), aTransform);
}
} // namespace mozilla
#endif // !defined(ArrayAlgorithm_h___)