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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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 "SlicedInputStream.h"
#include "nsISeekableStream.h"
#include "nsStreamUtils.h"
NS_IMPL_ISUPPORTS(SlicedInputStream, nsIInputStream,
nsICloneableInputStream, nsIAsyncInputStream)
SlicedInputStream::SlicedInputStream(nsIInputStream* aInputStream,
uint64_t aStart, uint64_t aLength)
: mInputStream(aInputStream)
, mStart(aStart)
, mLength(aLength)
, mCurPos(0)
, mClosed(false)
{
MOZ_ASSERT(aInputStream);
}
SlicedInputStream::~SlicedInputStream()
{}
NS_IMETHODIMP
SlicedInputStream::Close()
{
mClosed = true;
return NS_OK;
}
// nsIInputStream interface
NS_IMETHODIMP
SlicedInputStream::Available(uint64_t* aLength)
{
if (mClosed) {
return NS_BASE_STREAM_CLOSED;
}
nsresult rv = mInputStream->Available(aLength);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
// Let's remove extra length from the end.
if (*aLength + mCurPos > mStart + mLength) {
*aLength -= XPCOM_MIN(*aLength, (*aLength + mCurPos) - (mStart + mLength));
}
// Let's remove extra length from the begin.
if (mCurPos < mStart) {
*aLength -= XPCOM_MIN(*aLength, mStart - mCurPos);
}
return NS_OK;
}
NS_IMETHODIMP
SlicedInputStream::Read(char* aBuffer, uint32_t aCount, uint32_t* aReadCount)
{
return ReadSegments(NS_CopySegmentToBuffer, aBuffer, aCount, aReadCount);
}
NS_IMETHODIMP
SlicedInputStream::ReadSegments(nsWriteSegmentFun aWriter, void* aClosure,
uint32_t aCount, uint32_t *aResult)
{
uint32_t result;
if (!aResult) {
aResult = &result;
}
*aResult = 0;
if (mClosed) {
return NS_BASE_STREAM_CLOSED;
}
if (mCurPos < mStart) {
nsCOMPtr<nsISeekableStream> seekableStream =
do_QueryInterface(mInputStream);
if (seekableStream) {
nsresult rv = seekableStream->Seek(nsISeekableStream::NS_SEEK_SET,
mStart);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
mCurPos = mStart;
} else {
char buf[4096];
while (mCurPos < mStart) {
uint32_t bytesRead;
uint64_t bufCount = XPCOM_MIN(mStart - mCurPos, (uint64_t)sizeof(buf));
nsresult rv = mInputStream->Read(buf, bufCount, &bytesRead);
if (NS_WARN_IF(NS_FAILED(rv)) || bytesRead == 0) {
return rv;
}
mCurPos += bytesRead;
}
}
}
// Let's reduce aCount in case it's too big.
if (mCurPos + aCount > mStart + mLength) {
aCount = mStart + mLength - mCurPos;
}
char buf[4096];
while (mCurPos < mStart + mLength && *aResult < aCount) {
uint32_t bytesRead;
uint64_t bufCount = XPCOM_MIN(aCount - *aResult, (uint32_t)sizeof(buf));
nsresult rv = mInputStream->Read(buf, bufCount, &bytesRead);
if (NS_WARN_IF(NS_FAILED(rv)) || bytesRead == 0) {
return rv;
}
mCurPos += bytesRead;
uint32_t bytesWritten = 0;
while (bytesWritten < bytesRead) {
uint32_t writerCount = 0;
rv = aWriter(this, aClosure, buf + bytesWritten, *aResult,
bytesRead - bytesWritten, &writerCount);
if (NS_FAILED(rv) || writerCount == 0) {
return NS_OK;
}
MOZ_ASSERT(writerCount <= bytesRead - bytesWritten);
bytesWritten += writerCount;
*aResult += writerCount;
}
}
return NS_OK;
}
NS_IMETHODIMP
SlicedInputStream::IsNonBlocking(bool* aNonBlocking)
{
return mInputStream->IsNonBlocking(aNonBlocking);
}
// nsICloneableInputStream interface
NS_IMETHODIMP
SlicedInputStream::GetCloneable(bool* aCloneable)
{
*aCloneable = true;
return NS_OK;
}
NS_IMETHODIMP
SlicedInputStream::Clone(nsIInputStream** aResult)
{
nsCOMPtr<nsIInputStream> clonedStream;
nsCOMPtr<nsIInputStream> replacementStream;
nsresult rv = NS_CloneInputStream(mInputStream, getter_AddRefs(clonedStream),
getter_AddRefs(replacementStream));
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
if (replacementStream) {
mInputStream = replacementStream.forget();
}
nsCOMPtr<nsIInputStream> sis =
new SlicedInputStream(clonedStream, mStart, mLength);
sis.forget(aResult);
return NS_OK;
}
// nsIAsyncInputStream interface
NS_IMETHODIMP
SlicedInputStream::CloseWithStatus(nsresult aStatus)
{
nsCOMPtr<nsIAsyncInputStream> asyncStream =
do_QueryInterface(mInputStream);
if (!asyncStream) {
return NS_ERROR_FAILURE;
}
return asyncStream->CloseWithStatus(aStatus);
}
NS_IMETHODIMP
SlicedInputStream::AsyncWait(nsIInputStreamCallback* aCallback,
uint32_t aFlags,
uint32_t aRequestedCount,
nsIEventTarget* aEventTarget)
{
nsCOMPtr<nsIAsyncInputStream> asyncStream =
do_QueryInterface(mInputStream);
if (!asyncStream) {
return NS_ERROR_FAILURE;
}
return asyncStream->AsyncWait(aCallback, aFlags, aRequestedCount,
aEventTarget);
}
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