gecko-dev/dom/file/BlobImpl.cpp

77 строки
2.0 KiB
C++
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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/. */
#include "BlobImpl.h"
#include "File.h"
#include "mozilla/CheckedInt.h"
namespace mozilla {
namespace dom {
// Makes sure that aStart and aEnd is less then or equal to aSize and greater
// than 0
static void
ParseSize(int64_t aSize, int64_t& aStart, int64_t& aEnd)
{
CheckedInt64 newStartOffset = aStart;
if (aStart < -aSize) {
newStartOffset = 0;
}
else if (aStart < 0) {
newStartOffset += aSize;
}
else if (aStart > aSize) {
newStartOffset = aSize;
}
CheckedInt64 newEndOffset = aEnd;
if (aEnd < -aSize) {
newEndOffset = 0;
}
else if (aEnd < 0) {
newEndOffset += aSize;
}
else if (aEnd > aSize) {
newEndOffset = aSize;
}
if (!newStartOffset.isValid() || !newEndOffset.isValid() ||
newStartOffset.value() >= newEndOffset.value()) {
aStart = aEnd = 0;
}
else {
aStart = newStartOffset.value();
aEnd = newEndOffset.value();
}
}
already_AddRefed<BlobImpl>
BlobImpl::Slice(const Optional<int64_t>& aStart,
const Optional<int64_t>& aEnd,
const nsAString& aContentType,
ErrorResult& aRv)
{
// Truncate aStart and aEnd so that we stay within this file.
uint64_t thisLength = GetSize(aRv);
if (NS_WARN_IF(aRv.Failed())) {
return nullptr;
}
int64_t start = aStart.WasPassed() ? aStart.Value() : 0;
int64_t end = aEnd.WasPassed() ? aEnd.Value() : (int64_t)thisLength;
ParseSize((int64_t)thisLength, start, end);
nsAutoString type(aContentType);
Blob::MakeValidBlobType(type);
return CreateSlice((uint64_t)start, (uint64_t)(end - start), type, aRv);
}
NS_IMPL_ISUPPORTS(BlobImpl, BlobImpl)
} // namespace dom
} // namespace mozilla